compounds biodegradation processes: Topics by WorldWideScience.org

Sample records for compounds biodegradation processes

Biodegradation of creosote compounds: Comparison of experiments at different scales

DEFF Research Database (Denmark)

Broholm, K.; Arvin, Erik

2001-01-01

of the pyrroles on the biodegradation of benzene, and the biodegradation of benzothiophene occurs only in the presence of a primary substrate. The experiments show that some biodegradation processes of organic compounds may be common to different microorganisms.......This paper compares the results of biodegradation experiments with creosote compounds performed at different scales. The experiments include field observations, field experiments, large-scale intact laboratory column experiments, model fracture experiments, and batch experiments. Most...... of the experiments were conducted with till or ground water from the field site at Ringe on the island of Funen. Although the experiments were conducted on different scales, they revealed that some phenomena-e.g., an extensive biodegradation potential of several of the creosote compounds, the inhibitory influence...
Biodegradation tests of mercaptocarboxylic acids, their esters, related divalent sulfur compounds and mercaptans.

Science.gov (United States)

Rücker, Christoph; Mahmoud, Waleed M M; Schwartz, Dirk; Kümmerer, Klaus

2018-04-17

Mercaptocarboxylic acids and their esters, a class of difunctional compounds bearing both a mercapto and a carboxylic acid or ester functional group, are industrial chemicals of potential environmental concern. Biodegradation of such compounds was systematically investigated here, both by literature search and by experiments (Closed Bottle Test OECD 301D and Manometric Respirometry Test OECD 301F). These compounds were found either readily biodegradable or at least biodegradable to a significant extent. Some related compounds of divalent sulfur were tested for comparison (mercaptans, sulfides, disulfides). For the two relevant monofunctional compound classes, carboxylic acids/esters and mercaptans, literature data were compiled, and by comparison with structurally similar compounds without these functional groups, the influence of COOH/COOR' and SH groups on biodegradability was evaluated. Thereby, an existing rule of thumb for biodegradation of carboxylic acids/esters was supported by experimental data, and a rule of thumb could be formulated for mercaptans. Concurrent to biodegradation, abiotic processes were observed in the experiments, rapid oxidative formation of disulfides (dimerisation of monomercaptans and cyclisation of dimercaptans) and hydrolysis of esters. Some problems that compromise the reproducibility of biodegradation test results were discussed.
Biodegradable compounds: Rheological, mechanical and thermal properties

Science.gov (United States)

Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

2015-12-01

Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.
Aerobic biodegradation of organotin compounds in activated sludge batch reactors

Energy Technology Data Exchange (ETDEWEB)

Stasinakis, Athanasios S. [Department of Environmental Studies, Water and Air Quality Laboratory, University of the Aegean, University Hill, Mytilene 81 100 (Greece)]. E-mail: astas@env.aegean.gr; Thomaidis, Nikolaos S. [Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Zografou, Athens 157 71 (Greece); Nikolaou, Anastasia [Department of Environmental Studies, Water and Air Quality Laboratory, University of the Aegean, University Hill, Mytilene 81 100 (Greece); Kantifes, Andreas [Department of Environmental Studies, Water and Air Quality Laboratory, University of the Aegean, University Hill, Mytilene 81 100 (Greece)

2005-04-01

The biodegradation behavior of four organotin (OT) compounds, namely tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT) and triphenyltin (TPhT), was studied in lab-scale activated sludge batch reactors. The activated sludge was spiked with the OT compounds at a level of 100 {mu}g l{sup -1} as Sn. Determination of the OT compounds by GC-FPD after ethylation in the dissolved and particulate phase revealed that 24 h after the start of the experiments, almost the total of OT compounds has been removed from the dissolved phase and is associated with the suspended solids. Calculation of mass balance in batch reactors showed that OT compounds biodegradation was performed via a sequential dealkylation process. Removals due to biodegradation were differentiated according to the parent compound. In experiments with non-acclimatized biomass, a percentage of 27.1, 8.3, 73.8 and 51.3 was still present as TBT, DBT, MBT and TPhT, respectively, at the end of the experiment (18th day). Half-lives (t{sub 1/2}) of 10.2 and 5.1 days were calculated for TBT and DBT, respectively, whereas apparent t{sub 1/2} values could not be determined for MBT and TPhT (t{sub 1/2} > 18 days). The capacity of activated sludge to biodegrade OT compounds in the absence of supplemental substrate indicated that these compounds can be metabolized as single sources of carbon and energy in activated sludge systems. Excluding TBT, the presence of low concentrations of supplemental substrate did not affect the biodegradation potential of activated sludge. The acclimatization of biomass on OT compounds enhanced significantly biodegradation, resulting in significant decreases of half-lives of OT compounds. As a result in the presence of acclimatized biomass, half-lives of 1.4, 3.6, 9.8 and 5.0 days were calculated for TBT, DBT, MBT and TPhT, respectively. - The fate of organotins is assessed in activated sludge systems.
Aerobic biodegradation of organotin compounds in activated sludge batch reactors

International Nuclear Information System (INIS)

Stasinakis, Athanasios S.; Thomaidis, Nikolaos S.; Nikolaou, Anastasia; Kantifes, Andreas

2005-01-01

The biodegradation behavior of four organotin (OT) compounds, namely tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT) and triphenyltin (TPhT), was studied in lab-scale activated sludge batch reactors. The activated sludge was spiked with the OT compounds at a level of 100 μg l -1 as Sn. Determination of the OT compounds by GC-FPD after ethylation in the dissolved and particulate phase revealed that 24 h after the start of the experiments, almost the total of OT compounds has been removed from the dissolved phase and is associated with the suspended solids. Calculation of mass balance in batch reactors showed that OT compounds biodegradation was performed via a sequential dealkylation process. Removals due to biodegradation were differentiated according to the parent compound. In experiments with non-acclimatized biomass, a percentage of 27.1, 8.3, 73.8 and 51.3 was still present as TBT, DBT, MBT and TPhT, respectively, at the end of the experiment (18th day). Half-lives (t 1/2 ) of 10.2 and 5.1 days were calculated for TBT and DBT, respectively, whereas apparent t 1/2 values could not be determined for MBT and TPhT (t 1/2 > 18 days). The capacity of activated sludge to biodegrade OT compounds in the absence of supplemental substrate indicated that these compounds can be metabolized as single sources of carbon and energy in activated sludge systems. Excluding TBT, the presence of low concentrations of supplemental substrate did not affect the biodegradation potential of activated sludge. The acclimatization of biomass on OT compounds enhanced significantly biodegradation, resulting in significant decreases of half-lives of OT compounds. As a result in the presence of acclimatized biomass, half-lives of 1.4, 3.6, 9.8 and 5.0 days were calculated for TBT, DBT, MBT and TPhT, respectively. - The fate of organotins is assessed in activated sludge systems
Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part B--Nitrogen-, Sulfur-, and Oxygen-Containing Heterocyclic Aromatic Compounds.

Science.gov (United States)

Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

2015-07-01

Present study focused on the biodegradation of various heterocyclic nitrogen, sulfur, and oxygen (NSO) compounds using naphthalene-enriched culture. Target compounds in the study were pyridine, quinoline, benzothiophene, and benzofuran. Screening studies were carried out using different microbial consortia enriched with specific polycyclic aromatic hydrocarbon (PAH) and NSO compounds. Among different microbial consortia, naphthalene-enriched culture was the most efficient consortium based on high substrate degradation rate. Substrate degradation rate with naphthalene-enriched culture followed the order pyridine > quinoline > benzofuran > benzothiophene. Benzothiophene and benzofuran were found to be highly recalcitrant pollutants. Benzothiophene could not be biodegraded when concentration was above 50 mg/l. It was observed that 2-(1H)-quinolinone, benzothiophene-2-one, and benzofuran-2,3-dione were formed as metabolic intermediates during biodegradation of quinoline, benzothiophene, and benzofuran, respectively. Quinoline-N and pyridine-N were transformed into free ammonium ions during the biodegradation process. Biodegradation pathways for various NSO compounds are proposed. Monod inhibition model was able to simulate single substrate biodegradation kinetics satisfactorily. Benzothiophene and benzofuran biodegradation kinetics, in presence of acetone, was simulated using a generalized multi-substrate model.
Molecular basis of biodegradation of chloroaromatic compounds

Energy Technology Data Exchange (ETDEWEB)

Sangodkar, U M.X.; Aldrich, T L; Haugland, R A; Johnson, J; Rothmel, R K; Chakrabarty, A M [Illinois Univ., Chicago (USA). Coll. of Medicine; Chapman, P J [Environmental Protection Agency, Gulf Breeze, FL (USA). Microbial Ecology and Biotechnology

1989-01-01

Chlorinated aromatic hydrocarbons are widely used in industry and agriculture, and comprise the bulk of environmental pollutants. Although simple aromatic compounds are biodegradable by a variety of degradative pathways, their halogenated counterparts are more resistant to bacterial attack and often necessitate evolution of novel pathways. An understanding of such evolutionary processes is essential for developing genetically improved strains capable of mineralizing highly chlorinated compounds. This article provides an overview of the genetic aspects of dissimilation of chloroaromatic compounds and discusses the potential of gene manipulation to promote enhanced evolution of the degradation pathways. (orig.).
Compounds interaction on biodegradation of toluene and methyl ...

African Journals Online (AJOL)

MEK) mixtures in a composite bead biofilter was investigated. The biodegradation rate of two compounds in the exponential growth phase and stationary phase for the single compound and two compounds mixing systems was determined.
Advances in Biodegradation of Multiple Volatile Organic Compounds

Science.gov (United States)

Zhang, M.; Yoshikawa, M.

2017-12-01

Bioremediation of soil and groundwater containing multiple contaminants remains a challenge in environmental science and engineering because complete biodegradation of all components is necessary but very difficult to accomplish in practice. This presentation provides a brief overview on advances in biodegradation of multiple volatile organic compounds (VOCs) including chlorinated ethylenes, benzene, toluene and dichloromethane (DCM). Case studies on aerobic biodegradation of benzene, toluene and DCM, and integrated anaerobic-aerobic biodegradation of 7 contaminants, specifically, tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), vinyl chloride (VC), DCM, benzene and toluene will be provided. Recent findings based on systematic laboratory experiments indicated that aerobic toluene degradation can be enhanced by co-existence of benzene. Propioniferax, not a known benzene, toluene and DCM degrader can be a key microorganism that involves in biodegradation when the three contaminants co-exist. Integrated anaerobic-aerobic biodegradation is capable of completely degrading the seven VOCs with initial concentrations less than 30 mg/L. Dehalococcoides sp., generally considered sensitive to oxygen, can survive aerobic conditions for at least 28 days, and can be activated during the subsequent anaerobic biodegradation. This presentation may provide a systematic information about biodegradation of multiple VOCs, and a scientific basis for the complete bioremediation of multiple contaminants in situ.
Improvement of landfill leachate biodegradability with ultrasonic process.

Directory of Open Access Journals (Sweden)

Amir Hossein Mahvi

Full Text Available Landfills leachates are known to contain recalcitrant and/or non-biodegradable organic substances and biological processes are not efficient in these cases. A promising alternative to complete oxidation of biorecalcitrant leachate is the use of ultrasonic process as pre-treatment to convert initially biorecalcitrant compounds to more readily biodegradable intermediates. The objectives of this study are to investigate the effect of ultrasonic process on biodegradability improvement. After the optimization by factorial design, the ultrasonic were applied in the treatment of raw leachates using a batch wise mode. For this, different scenarios were tested with regard to power intensities of 70 and 110 W, frequencies of 30, 45 and 60 KHz, reaction times of 30, 60, 90 and 120 minutes and pH of 3, 7 and 10. For determining the effects of catalysts on sonication efficiencies, 5 mg/l of TiO(2 and ZnO have been also used. Results showed that when applied as relatively brief pre-treatment systems, the sonocatalysis processes induce several modifications of the matrix, which results in significant enhancement of its biodegradability. For this reason, the integrated chemical-biological systems proposed here represent a suitable solution for the treatment of landfill leachate samples.
Biodegradation of Volatile Organic Compounds and Their Effects on Biodegradability under Co-Existing Conditions.

Science.gov (United States)

Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

2017-09-27

Volatile organic compounds (VOCs) are major pollutants that are found in contaminated sites, particularly in developed countries such as Japan. Various microorganisms that degrade individual VOCs have been reported, and genomic information related to their phylogenetic classification and VOC-degrading enzymes is available. However, the biodegradation of multiple VOCs remains a challenging issue. Practical sites, such as chemical factories, research facilities, and illegal dumping sites, are often contaminated with multiple VOCs. In order to investigate the potential of biodegrading multiple VOCs, we initially reviewed the biodegradation of individual VOCs. VOCs include chlorinated ethenes (tetrachloroethene, trichloroethene, dichloroethene, and vinyl chloride), BTEX (benzene, toluene, ethylbenzene, and xylene), and chlorinated methanes (carbon tetrachloride, chloroform, and dichloromethane). We also summarized essential information on the biodegradation of each kind of VOC under aerobic and anaerobic conditions, together with the microorganisms that are involved in VOC-degrading pathways. Interactions among multiple VOCs were then discussed based on concrete examples. Under conditions in which multiple VOCs co-exist, the biodegradation of a VOC may be constrained, enhanced, and/or unaffected by other compounds. Co-metabolism may enhance the degradation of other VOCs. In contrast, constraints are imposed by the toxicity of co-existing VOCs and their by-products, catabolite repression, or competition between VOC-degrading enzymes. This review provides fundamental, but systematic information for designing strategies for the bioremediation of multiple VOCs, as well as information on the role of key microorganisms that degrade VOCs.
Biodegradation of Volatile Organic Compounds and Their Effects on Biodegradability under Co-Existing Conditions

Science.gov (United States)

Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

2017-01-01

Volatile organic compounds (VOCs) are major pollutants that are found in contaminated sites, particularly in developed countries such as Japan. Various microorganisms that degrade individual VOCs have been reported, and genomic information related to their phylogenetic classification and VOC-degrading enzymes is available. However, the biodegradation of multiple VOCs remains a challenging issue. Practical sites, such as chemical factories, research facilities, and illegal dumping sites, are often contaminated with multiple VOCs. In order to investigate the potential of biodegrading multiple VOCs, we initially reviewed the biodegradation of individual VOCs. VOCs include chlorinated ethenes (tetrachloroethene, trichloroethene, dichloroethene, and vinyl chloride), BTEX (benzene, toluene, ethylbenzene, and xylene), and chlorinated methanes (carbon tetrachloride, chloroform, and dichloromethane). We also summarized essential information on the biodegradation of each kind of VOC under aerobic and anaerobic conditions, together with the microorganisms that are involved in VOC-degrading pathways. Interactions among multiple VOCs were then discussed based on concrete examples. Under conditions in which multiple VOCs co-exist, the biodegradation of a VOC may be constrained, enhanced, and/or unaffected by other compounds. Co-metabolism may enhance the degradation of other VOCs. In contrast, constraints are imposed by the toxicity of co-existing VOCs and their by-products, catabolite repression, or competition between VOC-degrading enzymes. This review provides fundamental, but systematic information for designing strategies for the bioremediation of multiple VOCs, as well as information on the role of key microorganisms that degrade VOCs. PMID:28904262
Removal of cyanide compounds from coking wastewater by ferrous sulfate: Improvement of biodegradability.

Science.gov (United States)

Yu, Xubiao; Xu, Ronghua; Wei, Chaohai; Wu, Haizhen

2016-01-25

The effect of ferrous sulfate (FeSO4) treatment on the removal of cyanide compounds and the improvement of biodegradability of coking wastewater were investigated by varying Fe:TCN molar ratios. Results suggested that the reaction between FeSO4 and coking wastewater was a two-step process. At the first step, i.e., 0≤Fe:TCN≤1.0, the reaction mechanisms were dominated by the precipitation of FeS, the complexation of CN(-), and the coagulation of organic compounds. The COD of coking wastewater decreased from 3748.1 mg/L to 3450.2 mg/L, but BOD5:COD (B/C) was improved from 0.30 to 0.51. At the second step, i.e., 1.0cyanide compounds by ferrous ions was the dominating mechanism. The COD showed a continuous increase to 3542.2 mg/L (Fe:TCN=3.2) due to the accumulated ferrous ions in coking wastewater. Moreover, B/C decreased progressively to 0.35, which was attributed to the negative effects of excess ferrous ions on biodegradability. To improve coking wastewater's biodegradability, a minimum ferrous dosage is required to complete the first step reaction. However, the optimum ferrous dosage should be determined to control a safe residual TCN in coking wastewater for the further biological treatment. Copyright © 2015 Elsevier B.V. All rights reserved.
In silico identification and construction of microbial gene clusters associated with biodegradation of xenobiotic compounds.

Science.gov (United States)

Awasthi, Garima; Kumari, Anjani; Pant, Aditya Bhushan; Srivastava, Prachi

2018-01-01

Chemical substances not showing any importance in existence of biological systems and causing serious health hazards may be designated as Xenobiotic compound. Elimination or degradation of these unwanted substances is a major issue of concern for current time research. Process of biodegradation is a very important aspect of current research as discussed in current manuscript. Current study focuses on the detailed mining of data for the construction of microbial consortia for wide range of xenobiotics compounds. Intensive literature search was done for the construction of this library. Desired data was retrieved from NCBI in fasta format. Data was analysed through homology approaches by using BLAST. This homology based searched enriched with a great vision that not only bacterial population but many other cheap and potential sources are available for different xenobiotic degradation. Though it was focused that bacterial population covers a major part of biodegradation which is near about 90.6% but algae and fungi are also showing promising future in degradation of some important xenobiotic compounds. Analysis of data reveals that Pseudomonas putida has potential for degrading maximum compounds. Establishment of correlation through cluster analysis signifies that Pseudomonas putida, Aspergillus niger and Skeletonema costatum can have combined traits that can be used in finding out actual evolutionary relationship between these species. These findings may also givea new outcome in terms of much cheaper and eco-friendly source in the area of biodegradation of specified xenobiotic compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.
Granular activated carbon for simultaneous adsorption and biodegradation of toxic oil sands process-affected water organic compounds.

Science.gov (United States)

Islam, Md Shahinoor; Zhang, Yanyan; McPhedran, Kerry N; Liu, Yang; Gamal El-Din, Mohamed

2015-04-01

Naphthenic acids (NAs) released into oil sands process-affected water (OSPW) during bitumen processing in Northern Alberta are problematic for oil sands industries due to their toxicity in the environment and resistance to degradation during conventional wastewater treatment processes. Granular activated carbon (GAC) has shown to be an effective media in removing biopersistent organics from wastewater using a combination of adsorption and biodegradation removal mechanisms. A simultaneous GAC (0.4 g GAC/L) adsorption and biodegradation (combined treatment) study was used for the treatment of raw and ozonated OSPW. After 28 days of batch treatment, classical and oxidized NAs removals for raw OSPW were 93.3% and 73.7%, and for ozonated OSPW were 96.2% and 77.1%, respectively. Synergetic effects of the combined treatment process were observed in removals of COD, the acid extractable fraction, and oxidized NAs, which indicated enhanced biodegradation and bioregeneration in GAC biofilms. A bacteria copy number >10(8) copies/g GAC on GAC surfaces was found using quantitative real time polymerase chain reaction after treatment for both raw and ozonated OSPW. A Microtox(®) acute toxicity test (Vibrio fischeri) showed effective toxicity removal (>95.3%) for the combined treatments. Therefore, the simultaneous GAC adsorption and biodegradation treatment process is a promising technology for the elimination of toxic OSPW NAs. Copyright © 2015 Elsevier Ltd. All rights reserved.
Improve the biodegradability of post-hydrothermal liquefaction wastewater with ozone: conversion of phenols and N-heterocyclic compounds.

Science.gov (United States)

Yang, Libin; Si, Buchun; Martins, Marcio Arêdes; Watson, Jamison; Chu, Huaqiang; Zhang, Yuanhui; Tan, Xiaobo; Zhou, Xuefei; Zhang, Yalei

2017-04-01

Hydrothermal liquefaction is a promising technology to convert wet biomass into bio-oil. However, post-hydrothermal liquefaction wastewater (PHWW) is also produced during the process. This wastewater contains a high concentration of organic compounds, including phenols and N-heterocyclic compounds which are two main inhibitors for biological treatment. Thus, proper treatment is required. In this work, ozone was used to convert phenols and N-heterocyclic compounds with a dosage range of 0-4.64 mg O 3 /mL PHWW. After ozone treatment, the phenols were fully converted, and acids were produced. However, N-heterocyclic compounds were found to have a low conversion rate (21.7%). The kinetic analysis for the degradation of phenols and N-heterocyclic compounds showed that the substitute played an important role in determining the priority of ozone reactions. The OH moiety in the ring compounds (phenols and pyridinol) may form hydroxyl radical, which lead to an efficient reaction. A substantial improved biodegradability of PHWW was observed after ozone treatment. The ratio of BOD 5 /COD was increased by about 32.36%, and reached a maximum of 0.41. The improved biodegradability of PHWW was justified by the conversion of phenols and N-heterocyclic compounds.
Slowly biodegradable organic compounds impact the biostability of non-chlorinated drinking water produced from surface water.

Science.gov (United States)

Hijnen, W A M; Schurer, R; Bahlman, J A; Ketelaars, H A M; Italiaander, R; van der Wal, A; van der Wielen, P W J J

2018-02-01

It is possible to distribute drinking water without a disinfectant residual when the treated water is biologically stable. The objective of this study was to determine the impact of easily and slowly biodegradable compounds on the biostability of the drinking water at three full-scale production plants which use the same surface water, and on the regrowth conditions in the related distribution systems. Easily biodegradable compounds in the drinking water were determined with AOC-P17/Nox during 2012-2015. Slowly biodegradable organic compounds measured as particulate and/or high-molecular organic carbon (PHMOC), were monitored at the inlet and after the different treatment stages of the three treatments during the same period. The results show that PHMOC (300-470 μg C L -1 ) was approximately 10% of the TOC in the surface water and was removed to 50-100 μg C L -1 . The PHMOC in the water consisted of 40-60% of carbohydrates and 10% of proteins. A significant and strong positive correlation was observed for PHMOC concentrations and two recently introduced bioassay methods for slowly biodegradable compounds (AOC-A3 and biomass production potential, BPC 14 ). Moreover, these three parameters in the biological active carbon effluent (BACF) of the three plants showed a positive correlation with regrowth in the drinking water distribution system, which was assessed with Aeromonas, heterotrophic plate counts, coliforms and large invertebrates. In contrast, the AOC-P17/Nox concentrations did not correlate with these regrowth parameters. We therefore conclude that slowly biodegradable compounds in the treated water from these treatment plants seem to have a greater impact on regrowth in the distribution system than easily biodegradable compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.
Influence of Biodegradation on the Organic Compounds Composition of Peat.

Science.gov (United States)

Serebrennikova, Olga; Svarovskaya, Lidiya; Duchko, Maria; Strelnikova, Evgeniya; Russkikh, Irina

2016-06-01

Largest wetland systems are situated on the territory of the Tomsk region. They are characterized by the high content of organic matter (OM), which undergoes transformation as a result of physical, chemical and biological processes. The composition of peat OM is determined by the nature of initial peat-forming plants, their transformation products and bacteria. An experiment in stimulated microbial impact was carried out for estimating the influence of biodegradation on the composition of peat lipids. The composition of the functional groups in the bacterial biomass, initial peat and peat after biodegradation was determined by IR-spectroscopy using the spectrometer NICOLET 5700. The IR spectra of peat and bacteria organic matter are characterized by the presence of absorption bands in ranges: 3400-3200 cm-1, which refers to the stretching vibrations of OH-group of carboxylic acids and various types of hydrogen bonds; 1738-1671 cm-1 - characteristic stretching vibrations of the C = O group of carboxylic acids and ketones; 1262 cm-1 - stretching vibrations of C-O of carboxylic acids. Group and individual composition of organic compounds in studied samples was determined by gas chromatography-mass-spectrometry.
Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part A-Monocyclic and Polycyclic Aromatic Hydrocarbons.

Science.gov (United States)

Oberoi, Akashdeep Singh; Philip, Ligy; Bhallamudi, S Murty

2015-08-01

Present study focused on the screening of bacterial consortium for biodegradation of monocyclic aromatic hydrocarbon (MAH) and polycyclic aromatic hydrocarbons (PAHs). Target compounds in the present study were naphthalene, acenaphthene, phenanthrene (PAHs), and benzene (MAH). Microbial consortia enriched with the above target compounds were used in screening experiments. Naphthalene-enriched consortium was found to be the most efficient consortium, based on its substrate degradation rate and its ability to degrade other aromatic pollutants with significantly high efficiency. Substrate degradation rate with naphthalene-enriched culture followed the order benzene > naphthalene > acenaphthene > phenanthrene. Chryseobacterium and Rhodobacter were discerned as the predominant species in naphthalene-enriched culture. They are closely associated to the type strain Chryseobacterium arthrosphaerae and Rhodobacter maris, respectively. Single substrate biodegradation studies with naphthalene (PAH) and benzene (MAH) were carried out using naphthalene-enriched microbial consortium (NAPH). Phenol and 2-hydroxybenzaldehyde were identified as the predominant intermediates during benzene and naphthalene degradation, respectively. Biodegradation of toluene, ethyl benzene, xylene, phenol, and indole by NAPH was also investigated. Monod inhibition model was able to simulate biodegradation kinetics for benzene, whereas multiple substrate biodegradation model was able to simulate biodegradation kinetics for naphthalene.
Biodegradability enhancement of textile wastewater by electron beam irradiation

International Nuclear Information System (INIS)

Kim, Tak-Hyun; Lee, Jae-Kwang; Lee, Myun-Joo

2007-01-01

Textile wastewater generally contains various pollutants, which can cause problems during biological treatment. Electron beam radiation technology was applied to enhance the biodegradability of textile wastewater for an activated sludge process. The biodegradability (BOD 5 /COD) increased at a 1.0 kGy dose. The biorefractory organic compounds were converted into more easily biodegradable compounds such as organic acids having lower molecular weights. In spite of the short hydraulic retention time (HRT) of the activated sludge process, not only high organic removal efficiencies, but also high microbial activities were achieved. In conclusion, textile wastewater was effectively treated by the combined process of electron beam radiation and an activated sludge process

Processing and characterization of biodegradable soy plastics: Effects of crosslinking with glyoxal and thermal treatment

NARCIS (Netherlands)

Vaz, C.M.; Doeveren, van P.F.N.M.; Yilmaz, G.; Graaf, de L.A.; Reis, R.L.; Cunha, A.M.

2005-01-01

Processing and modification routes to produce and to improve properties of biodegradable plastics from soy isolate were studied. Soy isolate, acid-treated and crosslinked soy were subsequently compounded, extruded, and injection molded. Acetic acid and glyoxal were examined concerning their
PENGARUH PENAMBAHAN MAGNESIUM STEARAT DAN JENIS PROTEIN PADA PEMBUATAN BIODEGRADABLE FOAM DENGAN METODE BAKING PROCESS

Directory of Open Access Journals (Sweden)

Nanik hendrawati

2015-12-01

Full Text Available Biodegradable foam with cassava starch, protein and chitosan as the basic ingredients can be produced by using baking process method. Variation on magnesium stearate amount and protein types gave different effect on the biodegradable foam quality. The amount of magnesium stearate was varied as 1; 1.6; 2.2; 2.8; 3.4 and 4 % w/w and the sources of protein used in this research were taken from soy bean, peanut and egg white. The foam produced in this research was then tested for its mechanical properties, water resistance and biodegradability. It was found that addition of magnesium stearate as much as 4% w/w reduced water adsorption and biodegradability of foam. Magnesium stearate affected the ability of absorption of water and foam degradation, but did not influence on tensile strength. Different types of protein also gave influence on water absorption, biodegradability and tensile strength. The best improvement of tensile strenght among the compounds tested was shown by soy bean based foam.
Synthesis and toxicity evaluation of hydrophobic ionic liquids for volatile organic compounds biodegradation in a two-phase partitioning bioreactor

International Nuclear Information System (INIS)

Rodriguez Castillo, Alfredo Santiago; Guihéneuf, Solène; Le Guével, Rémy; Biard, Pierre-François

2016-01-01

Highlights: • Description of a VOC depollution system suitable with industrial processes, TPPB. • Novel association of TPPB and hydrophobic ionic liquids. • Synthesis of several hydrophobic ionic liquids designed to fit desired properties. • Toxicity evaluation of these ILs towards cells, animals and bacteria. - Abstract: Synthesis of several hydrophobic ionic liquids (ILs), which might be selected as good candidates for degradation of hydrophobic volatile organic compounds in a two-phase partitioning bioreactor (TPPB), were carried out. Several bioassays were also realized, such as toxicity evaluation on activated sludge and zebrafish, cytotoxicity, fluoride release in aqueous phase and biodegradability in order to verify their possible effects in case of discharge in the aquatic environment and/or human contact during industrial manipulation. The synthesized compounds consist of alkylimidazoliums, functionalized imidazoliums, isoqinoliniums, triazoliums, sulfoniums, pyrrolidiniums and morpholiniums and various counter-ions such as: PF_6"−, NTf_2"− and NfO"−. Toxicity evaluation on activated sludge of each compound (5% v/v of IL) was assessed by using a glucose uptake inhibition test. Toxicity against zebrafish and cytotoxicity were evaluated by the ImPACCell platform of Rennes (France). Fluoride release in water was estimated by regular measurements using ion chromatography equipment. IL biodegradability was determined by measuring BOD_2_8 of aqueous samples (compound concentration,1 mM). All ILs tested were not biodegradable; while some of them were toxic toward activated sludge. Isoquinolinium ILs were toxic to human cancerous cell lines. Nevertheless no toxicity was found against zebrafish Danio rerio. Only one IL released fluoride after long-time agitation.
Systemic approaches to biodegradation.

Science.gov (United States)

Trigo, Almudena; Valencia, Alfonso; Cases, Ildefonso

2009-01-01

Biodegradation, the ability of microorganisms to remove complex chemicals from the environment, is a multifaceted process in which many biotic and abiotic factors are implicated. The recent accumulation of knowledge about the biochemistry and genetics of the biodegradation process, and its categorization and formalization in structured databases, has recently opened the door to systems biology approaches, where the interactions of the involved parts are the main subject of study, and the system is analysed as a whole. The global analysis of the biodegradation metabolic network is beginning to produce knowledge about its structure, behaviour and evolution, such as its free-scale structure or its intrinsic robustness. Moreover, these approaches are also developing into useful tools such as predictors for compounds' degradability or the assisted design of artificial pathways. However, it is the environmental application of high-throughput technologies from the genomics, metagenomics, proteomics and metabolomics that harbours the most promising opportunities to understand the biodegradation process, and at the same time poses tremendous challenges from the data management and data mining point of view.
Biodegradation of phenolic compounds with oxidases from sorghum and non-defined mixed bacterium media

International Nuclear Information System (INIS)

Obame, C. E. L.; Savadogo, P. W.; Mamoudou, D. H.; Dembele, R. H.; Traore, A. S.

2009-01-01

The biodegradation of the phenolic compounds is performed using oxidative enzymes, e. g. polyphenol oxidases (PPOs) and peroxidases (POXs). These oxidases displaying a wide spectrum for the oxidation of phenolic compounds were isolated either from sorghum or mixed bacteria. Spectrophotometric methods were used to assess the monophenolase and diphenolase activities of PPOs as well as the hydrogen-dependant oxidation of POXs. (Author)
Biodegradation of phenolic compounds with oxidases from sorghum and non-defined mixed bacterium media

Energy Technology Data Exchange (ETDEWEB)

Obame, C. E. L.; Savadogo, P. W.; Mamoudou, D. H.; Dembele, R. H.; Traore, A. S.

2009-07-01

The biodegradation of the phenolic compounds is performed using oxidative enzymes, e. g. polyphenol oxidases (PPOs) and peroxidases (POXs). These oxidases displaying a wide spectrum for the oxidation of phenolic compounds were isolated either from sorghum or mixed bacteria. Spectrophotometric methods were used to assess the monophenolase and diphenolase activities of PPOs as well as the hydrogen-dependant oxidation of POXs. (Author)
Biodegradation of gasoline compounds (BTEX) in a water works sand filter

DEFF Research Database (Denmark)

Arvin, Erik; Engelsen, P.; Sebber, U.

2004-01-01

Various chemical compounds including aromatic gasoline compounds frequently contaminate drinking water wells in urban areas. Because ground water treatment is simple, usually consisting of aeration/stripping and sand-filtration, it is of significant interest to know the ability of the conventional...... treatment to remove the chemical contaminants. The removal of gasoline compounds was investigated in a two-stage pilot scale sand filter, each with a filter depth of 0.8-1 m and with a filtration rate of 7.6 m/h. The concentrations of aromatic compounds were in the range 7-15 mu g/L, which are realistically...... sand grains). Influent iron concentrations in the range 0-4 mg/L and backwashing did not adversely affect the biodegradation of hydrocarbons. This study has shown that a conventional biological active sand filter can act as an efficient barrier against gasoline compounds, thereby saving the consumer...
Biodegradation of chloroethene compounds in groundwater at Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, 1999-2010

Science.gov (United States)

Dinicola, R.S.; Huffman, R.L.

2012-01-01

The U.S. Geological Survey evaluated the biodegradation of chloroethene compounds in groundwater beneath the former landfill at Operable Unit 1 (OU 1) of the U.S. Naval Undersea Warfare Center (NUWC), Division Keyport. The predominant contaminants in groundwater are the chloroethene compounds trichloroethene, cis-1,2-dichloroethene, and vinyl chloride. The remedy selected for groundwater contamination at OU 1 includes phytoremediation and natural attenuation. In 1999, the U.S. Navy planted two hybrid poplar plantations, referred to as the northern and southern plantations, over the most contaminated parts of the landfill. The U.S. Navy monitors tree health, groundwater levels, and contaminant concentrations to assess the effectiveness of phytoremediation. The U.S. Geological Survey began a cooperative effort with the U.S. Navy in 1995 to monitor the effectiveness of natural attenuation processes for removing and controlling the migration of chloroethenes and chloroethanes. Field and laboratory studies from 1996 through 2000 demonstrated that biodegradation of chloroethenes and chloroethanes in shallow groundwater at OU 1 was substantial. The U.S. Geological Survey monitored geochemical and contaminant concentrations in groundwater annually from 2001 through 2010. This report presents groundwater geochemical and contaminant data collected by the U.S. Geological Survey during June 2010 and evaluates evidence for continued biodegradation of chloroethenes in groundwater.
Synthesis and toxicity evaluation of hydrophobic ionic liquids for volatile organic compounds biodegradation in a two-phase partitioning bioreactor

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Castillo, Alfredo Santiago [Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France); Université européenne de Bretagne (France); Guihéneuf, Solène, E-mail: solene.guiheneuf@wanadoo.fr [Université européenne de Bretagne, Université de Rennes 1, Sciences Chimiques de Rennes, UMR, CNRS 6226, Groupe Ingénierie Chimique & Molécules Pour le Vivant (ICMV), Bât. 10A, Campus de Beaulieu, Avenue du Général Leclerc, CS 74205, 35042 Rennes cedex (France); Le Guével, Rémy [Plate-forme ImPACcell Structure Fédérative de Recherche BIOSIT Université de Rennes 1, Bat. 8, Campus de Villejean, 2 Avenue du Pr. Leon Bernard, CS 34317, 35043 Rennes Cedex (France); Biard, Pierre-François [Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France); Université européenne de Bretagne (France); and others

2016-04-15

Highlights: • Description of a VOC depollution system suitable with industrial processes, TPPB. • Novel association of TPPB and hydrophobic ionic liquids. • Synthesis of several hydrophobic ionic liquids designed to fit desired properties. • Toxicity evaluation of these ILs towards cells, animals and bacteria. - Abstract: Synthesis of several hydrophobic ionic liquids (ILs), which might be selected as good candidates for degradation of hydrophobic volatile organic compounds in a two-phase partitioning bioreactor (TPPB), were carried out. Several bioassays were also realized, such as toxicity evaluation on activated sludge and zebrafish, cytotoxicity, fluoride release in aqueous phase and biodegradability in order to verify their possible effects in case of discharge in the aquatic environment and/or human contact during industrial manipulation. The synthesized compounds consist of alkylimidazoliums, functionalized imidazoliums, isoqinoliniums, triazoliums, sulfoniums, pyrrolidiniums and morpholiniums and various counter-ions such as: PF{sub 6}{sup −}, NTf{sub 2}{sup −} and NfO{sup −}. Toxicity evaluation on activated sludge of each compound (5% v/v of IL) was assessed by using a glucose uptake inhibition test. Toxicity against zebrafish and cytotoxicity were evaluated by the ImPACCell platform of Rennes (France). Fluoride release in water was estimated by regular measurements using ion chromatography equipment. IL biodegradability was determined by measuring BOD{sub 28} of aqueous samples (compound concentration,1 mM). All ILs tested were not biodegradable; while some of them were toxic toward activated sludge. Isoquinolinium ILs were toxic to human cancerous cell lines. Nevertheless no toxicity was found against zebrafish Danio rerio. Only one IL released fluoride after long-time agitation.
Processing biodegradable waste by applying aerobic digester EWA

Directory of Open Access Journals (Sweden)

Đokić Dragoslav

2014-01-01

Full Text Available The paper presents research results obtained in the process of processing biodegradable wastes, resulting from agricultural production as well as municipal waste. Aerobic fermenter EWA (stationed within the Institute for Forage Crops Globoder- Kruševac was using for this purpose, during the one month testing. Biodegradable material with different ratios of components was used for filling aerobic digester. EWA fermenter is certified device that is used to stabilize and hygienic disposal of biodegradable waste, including sewage sludge and animal products produced in accordance with European Union regulations. Fermenter is intended to be used for combustion in boilers for solid fuels with humidity of biomaterials below 30%.
Processing biodegradable waste by applying aerobic digester EWA

OpenAIRE

Đokić, Dragoslav; Lugić, Zoran; Terzić, Dragan; Jevtić, Goran; Milenković, Jasmina; Húrka, Miroslav; Stanisavljević, Rade

2014-01-01

The paper presents research results obtained in the process of processing biodegradable wastes, resulting from agricultural production as well as municipal waste. Aerobic fermenter EWA (stationed within the Institute for Forage Crops Globoder- Kruševac) was using for this purpose, during the one month testing. Biodegradable material with different ratios of components was used for filling aerobic digester. EWA fermenter is certified device that is used to stabilize and hygienic disposal of bi...
Lignin biodegradation by the ascomycete Chrysonilia sitophila.

Science.gov (United States)

Rodríguez, J; Ferraz, A; Nogueira, R F; Ferrer, I; Esposito, E; Durán, N

1997-01-01

The lignin biodegradation process has an important role in the carbon cycle of the biosphere. The study of this natural process has developed mainly with the use of basidiomycetes in laboratory investigations. This has been a logical approach since most of the microorganisms involved in lignocellulosic degradation belong to this class of fungi. However, other microorganisms such as ascomycetes and also some bacteria, are involved in the lignin decaying process. This work focuses on lignin biodegradation by a microorganism belonging to the ascomycete class, Chrysonilia sitophila. Lignin peroxidase production and characterization, mechanisms of lignin degradation (lignin model compounds and lignin in wood matrix) and biosynthesis of veratryl alcohol are outstanding. Applications of C. sitophila for effluent treatment, wood biodegradation and single-cell protein production are also discussed.
Biodegradation of resorcinol byPseudomonas sp.

Institute of Scientific and Technical Information of China (English)

Nader Hajizadeh; Najibeh Shirzad; Ali Farzi; Mojtaba Salouti; Azra Momeni

2016-01-01

ABSTRACT Objective:To investigate the ability ofPseudomonas sp. isolated from East Azarbaijan, Iran in bioremediation of resorcinol. Methods: Resorcinol biodegradation was evaluated using spectrophotometry and confirmed by gas chromatography-mass spectroscopy. Results:This isolate was able to remove up to 37.12% of resorcinol from contaminated water. Reusability experiments had confirmed the biodegradation process which produced seven intermediate compounds. These intermediates were characterized by gas chromatography-mass spectroscopy technique. The products of resorcinol biodegradation were apparently 1, 4-cyclohexadiene, nonadecene, 2-heptadecanone, 1-isopropyl-2-methoxy-4-methylbenzene, hexadecanoic acid, 9-octadecenoic acid, phenol and 5-methyl-2-(1-methylethyl). Conclusions: The findings revealed thatPseudomonas sp. is able to degrade resorcinol. Because of being an indigenous organism, this isolate is more compatible with the climate of the northwest region of Iran and possibly will be used for degradation of other similar aromatic compounds.
Cyanide removal by combined adsorption and biodegradation process

Directory of Open Access Journals (Sweden)

R. Roshan Dash, Ch. Balomajumder, A. Kumar

2006-04-01

Full Text Available Investigation of the effectiveness of simultaneous adsorption and biodegradation (SAB process over individual processes by using microbes Rhizopus oryzae and Stemphylium loti with granular activated carbon (GAC as adsorbent was carried out. The maximum removal efficiency of cyanide had been achieved by biodegradation alone was 83% by R. oryzae, while it was 90% by S. loti at initial pH of 5.6 and 7.2 respectively and at initial CN- concentration of 150 mg/L. In the combined process efficiency of R. oryzae closer to S. loti (95.3% and 98.6% respectively
New insights into polyurethane biodegradation and realistic prospects for the development of a sustainable waste recycling process.

Science.gov (United States)

Cregut, Mickael; Bedas, M; Durand, M-J; Thouand, G

2013-12-01

Polyurethanes are polymeric plastics that were first used as substitutes for traditional polymers suspected to release volatile organic hazardous substances. The limitless conformations and formulations of polyurethanes enabled their use in a wide variety of applications. Because approximately 10 Mt of polyurethanes is produced each year, environmental concern over their considerable contribution to landfill waste accumulation appeared in the 1990s. To date, no recycling processes allow for the efficient reuse of polyurethane waste due to their high resistance to (a)biotic disturbances. To find alternatives to systematic accumulation or incineration of polyurethanes, a bibliographic analysis was performed on major scientific advances in the polyurethane (bio)degradation field to identify opportunities for the development of new technologies to recondition this material. Until polymers exhibiting oxo- or hydro-biodegradative traits are generated, conventional polyurethanes that are known to be only slightly biodegradable are of great concern. The research focused on polyurethane biodegradation highlights recent attempts to reprocess conventional industrial polyurethanes via microbial or enzymatic degradation. This review describes several wonderful opportunities for the establishment of new processes for polyurethane recycling. Meeting these new challenges could lead to the development of sustainable management processes involving polymer recycling or reuse as environmentally safe options for industries. The ability to upgrade polyurethane wastes to chemical compounds with a higher added value would be especially attractive. © 2013.
An assessment of biodegradability of quaternary carbon-containing fragrance compounds: comparison of experimental OECD screening test results and in silico prediction data.

Science.gov (United States)

Seyfried, Markus; Boschung, Alain

2014-05-01

An assessment of biodegradability was carried out for fragrance substances containing quaternary carbons by using data obtained from Organisation for Economic Co-operation and Development (OECD) 301F screening tests for ready biodegradation and from Biowin and Catalogic prediction models. Despite an expected challenging profile, a relatively high percentage of common-use fragrance substances showed significant biodegradation under the stringent conditions applied in the OECD 301F test. Among 27 test compounds, 37% met the pass level criteria after 28 d, while another 26% indicated partial breakdown (≥20% biodegradation). For several compounds for which structural analogs were available, the authors found that structures that were rendered less water soluble by either the presence of an acetate ester or the absence of oxygen tended to degrade to a lesser extent compared to the primary alcohols or oxygenated counterparts under the test conditions applied. Difficulties were encountered when attempting to correlate experimental with in silico data. Whereas the Biowin model combinations currently recommended by regulatory agencies did not allow for a reliable discrimination between readily and nonbiodegradable compounds, only a comparably small proportion of the chemicals studied (30% and 63% depending on the model) fell within the applicability domain of Catalogic, a factor that critically reduced its predictive power. According to these results, currently neither Biowin nor Catalogic accurately reflects the potential for biodegradation of fragrance compounds containing quaternary carbons. © 2014 SETAC.
Kinetics of Petroleum-Contaminated Soil Biodegraded by An Indigenous Bacteria Bacillus megaterium

Directory of Open Access Journals (Sweden)

BAMBANG YUDONO

2010-12-01

Full Text Available Bioremediation of petroleum sludge was conducted by using land-farming method in micro scale and by applying an indigenous bacteria Bacillus megaterium The samples were from PT. Pertamina Musi Banyuasin district of South Sumatra. The research aim was to evaluate the performance of the bacteria in degrading petroleum sludge. The rate of the biodegradation process was determined by using differential method and the data analyses show that the reaction order is 0.74. Then, the rate of biodegradation constant was determined by using an integral method assuming that the biodegradation process was a first reaction order. From the calculation, it was revealed that the biodegradation reaction constant was 0.0204/day. The bioremediation-kinetics model is y = −0.0204X + 2.0365, and by using this model the bioremediation process could be ended after 99.83 days. The qualitative analysis was carried out by using GC-MS to investigate the components of compounds changed during the bioremediation process. The results show that the B. megaterium could degrade 99.32% of alkane compounds.
Biodegradation of vapor-phase toluene in unsaturated porous media: Column experiments

International Nuclear Information System (INIS)

Khan, Ali M.; Wick, Lukas Y.; Harms, Hauke; Thullner, Martin

2016-01-01

Biodegradation of organic chemicals in the vapor phase of soils and vertical flow filters has gained attention as promising approach to clean up volatile organic compounds (VOC). The drivers of VOC biodegradation in unsaturated systems however still remain poorly understood. Here, we analyzed the processes controlling aerobic VOC biodegradation in a laboratory setup mimicking the unsaturated zone above a shallow aquifer. The setup allowed for diffusive vapor-phase transport and biodegradation of three VOC: non-deuterated and deuterated toluene as two compounds of highly differing biodegradability but (nearly) identical physical and chemical properties, and MTBE as (at the applied experimental conditions) non-biodegradable tracer and internal control. Our results showed for toluene an effective microbial degradation within centimeter VOC transport distances despite high gas-phase diffusivity. Degradation rates were controlled by the reactivity of the compounds while oxic conditions were found everywhere in the system. This confirms hypotheses that vadose zone biodegradation rates can be extremely high and are able to prevent the outgassing of VOC to the atmosphere within a centimeter range if compound properties and site conditions allow for sufficiently high degradation rates. - Highlights: • The column setup allows resolving vapor-phase VOC concentration gradients at cm scale resolution. • Vapor-phase and liquid-phase concentrations are measured simultaneously. • Isotopically labelled VOC was used as reference species of low biodegradability. • Biodegradation rates in the unsaturated zone can be very high and act at a cm scale. • Unsaturated material can be an effective bio-barrier avoiding biodegradable VOC emissions. - Microbial degradation activity can be sufficient to remove VOC from unsaturated porous media after a few centimeter of vapor-phase diffusive transport and mayeffectively avoid atmospheric emissions.
Anaerobic biodegradation of fluoranthene under methanogenic conditions in presence of surface-active compounds

DEFF Research Database (Denmark)

Fuchedzhieva, Nadezhda; Karakashev, Dimitar Borisov; Angelidaki, Irini

2008-01-01

for the study were linear alkyl benzene sulphonates (LAS) and rhamnolipid-biosurfactant complex from Pseudomonas sp. PS-17. Biodegradation of fluoranthene was monitored by GC/MS for a period up to 12th day. No change in the fluoranthene concentration was registered after 7th day. The presence of LAS enhanced...... biodegradation was most likely as a result of the increased fluoranthene solubility. The results indicate that LAS can be considered as a promising agent for facilitation of the process of anaerobic polycyclic aromatic hydrocarbons (PAH) biodegradation under methanogenic conditions....
BTEX biodegradation by bacteria from effluents of petroleum refinery.

Science.gov (United States)

Mazzeo, Dânia Elisa Christofoletti; Levy, Carlos Emílio; de Angelis, Dejanira de Franceschi; Marin-Morales, Maria Aparecida

2010-09-15

Groundwater contamination with benzene, toluene, ethylbenzene and xylene (BTEX) has been increasing, thus requiring an urgent development of methodologies that are able to remove or minimize the damages these compounds can cause to the environment. The biodegradation process using microorganisms has been regarded as an efficient technology to treat places contaminated with hydrocarbons, since they are able to biotransform and/or biodegrade target pollutants. To prove the efficiency of this process, besides chemical analysis, the use of biological assessments has been indicated. This work identified and selected BTEX-biodegrading microorganisms present in effluents from petroleum refinery, and evaluated the efficiency of microorganism biodegradation process for reducing genotoxic and mutagenic BTEX damage through two test-systems: Allium cepa and hepatoma tissue culture (HTC) cells. Five different non-biodegraded BTEX concentrations were evaluated in relation to biodegraded concentrations. The biodegradation process was performed in a BOD Trak Apparatus (HACH) for 20 days, using microorganisms pre-selected through enrichment. Although the biodegradation usually occurs by a consortium of different microorganisms, the consortium in this study was composed exclusively of five bacteria species and the bacteria Pseudomonas putida was held responsible for the BTEX biodegradation. The chemical analyses showed that BTEX was reduced in the biodegraded concentrations. The results obtained with genotoxicity assays, carried out with both A. cepa and HTC cells, showed that the biodegradation process was able to decrease the genotoxic damages of BTEX. By mutagenic tests, we observed a decrease in damage only to the A. cepa organism. Although no decrease in mutagenicity was observed for HTC cells, no increase of this effect after the biodegradation process was observed either. The application of pre-selected bacteria in biodegradation processes can represent a reliable and

Enhancement of in situ biodegradation of organic compounds in groundwater by targeted pump and treat intervention

International Nuclear Information System (INIS)

Thornton, S.F.; Baker, K.M.; Bottrell, S.H.; Rolfe, S.A.; McNamee, P.; Forrest, F.; Duffield, P.; Wilson, R.D.; Fairburn, A.W.; Cieslak, L.A.

2014-01-01

Highlights: • Pumping reduces contaminant toxicity below levels which stimulate in situ biodegradation. • Pumping increases the mixing of background oxidants into the plume for anaerobic respiration. • Bacterial sulphate reduction is very sensitive to contaminant concentrations. • Stable isotope analysis confirms the contribution of different biodegradation processes. • Targeted pump and treatment can enhance the natural attenuation of complex plumes. - Abstract: This study demonstrates the value of targeted pump and treatment (PAT) to enhance the in situ biodegradation of organic contaminants in groundwater for improved restoration. The approach is illustrated for a plume of phenolic compounds in a sandstone aquifer, where PAT is used for hydraulic containment and removal of dissolved phase contaminants from specific depth intervals. Time-series analysis of the plume hydrochemistry and stable isotope composition of dissolved species (δ 34 S-SO 4 , δ 13 C-CH 4 , δ 13 C-TDIC (TDIC = Total Dissolved Inorganic Carbon)) in groundwater samples from high-resolution multilevel samplers were used to deduce changes in the relative significance of biodegradation processes and microbial activity in the plume, induced by the PAT system over 3 years. The PAT system has reduced the maximum contaminant concentrations (up to 6800 mg L −1 total phenols) in the plume by 50% to ∼70% at different locations. This intervention has (i) stimulated in situ biodegradation in general, with an approximate doubling of contaminant turnover based on TDIC concentration, which has increased from <200 mg L −1 to >350 mg L −1 , (ii) enhanced the activity of SO 4 -reducing microorganisms (marked by a declining SO 4 concentration with corresponding increase in SO 4 -δ 34 S to values >7–14‰ V-CDT relative to background values of 1.9–6.5‰ V-CDT ), and (iii) where the TDIC increase is greatest, has changed TDIC-δ 13 C from values of −10 to −15‰ V-PDB to ∼−20‰ V
Depletion of compounds from thin oil films in seawater

International Nuclear Information System (INIS)

Brakstad, O.G.; Faksness, L.G.; Melbye, A.G.

2002-01-01

When oil is spilled on water, the oil compounds distribute between droplets and water-soluble phases in the water column. Some small organic acids, phenols, BTEX, and aromatic compounds will dissolve completely, but larger polycyclic aromatic hydrocarbons (PAH) and alkanes will remain in the droplet fraction. The biodegradation of droplets occurs at the oil-water interface. A method for immobilizing the oil films onto hydrophobic surfaces was developed in order to obtain a stable oil surface during the biodegradation period. A test system was also established to determine the depletion of oil compounds from the oil phase, including both abiotic and biotic processes. Three North Sea oils were used in the study. Two were paraffinic oils rich in n-alkanes and aromatic compounds, and one was asphalthenic which was richer in branched alkanes and PAH. The biodegradation period was 2 months at 13 degrees C. Samples from the water and thin film on the fabric was analyzed for carbon 10 and carbon 36 by gas chromatography-flame ionization detection. Semi-volatile organic compounds were analyzed using gas chromatography-mass spectrometry. Results indicated that the depletion process for alkanes was completely caused by biodegradation, while aromatic compounds were depleted by abiotic dissolution as well as by biodegradation. The system has potential for determining oil depletion processes under controlled surface-to-volume conditions, such as thin oil films and dispersed oil droplets. In addition, the system can be used to determine the depletion process in flow-through systems. 13 refs., 3 tabs., 9 figs
Titanate nanotube coatings on biodegradable photopolymer scaffolds

Energy Technology Data Exchange (ETDEWEB)

Beke, S., E-mail: szabolcs.beke@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632, Pécs (Hungary); Scarpellini, A. [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Anjum, F.; Brandi, F. [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy)

2013-05-01

Rigid, biodegradable photopolymer scaffolds were coated with titanate nanotubes (TNTs) by using a spin-coating method. TNTs were synthesized by a hydrothermal process at 150 °C under 4.7 bar ambient pressure. The biodegradable photopolymer scaffolds were produced by mask-assisted excimer laser photocuring at 308 nm. For scaffold coating, a stable ethanolic TNT sol was prepared by a simple colloid chemical route without the use of any binding compounds or additives. Scanning electron microscopy along with elemental analysis revealed that the scaffolds were homogenously coated by TNTs. The developed TNT coating can further improve the surface geometry of fabricated scaffolds, and therefore it can further increase the cell adhesion. Highlights: ► Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. ► Titanate nanotube deposition was carried out without binding compounds or additives. ► The titanate nanotube coating can further improve the surface geometry of scaffolds. ► These reproducible platforms will be of high importance for biological applications.
Biochemical interpretation of quantitative structure-activity relationships (QSAR) for biodegradation of N-heterocycles: a complementary approach to predict biodegradability.

Science.gov (United States)

Philipp, Bodo; Hoff, Malte; Germa, Florence; Schink, Bernhard; Beimborn, Dieter; Mersch-Sundermann, Volker

2007-02-15

Prediction of the biodegradability of organic compounds is an ecologically desirable and economically feasible tool for estimating the environmental fate of chemicals. We combined quantitative structure-activity relationships (QSAR) with the systematic collection of biochemical knowledge to establish rules for the prediction of aerobic biodegradation of N-heterocycles. Validated biodegradation data of 194 N-heterocyclic compounds were analyzed using the MULTICASE-method which delivered two QSAR models based on 17 activating (OSAR 1) and on 16 inactivating molecular fragments (GSAR 2), which were statistically significantly linked to efficient or poor biodegradability, respectively. The percentages of correct classifications were over 99% for both models, and cross-validation resulted in 67.9% (GSAR 1) and 70.4% (OSAR 2) correct predictions. Biochemical interpretation of the activating and inactivating characteristics of the molecular fragments delivered plausible mechanistic interpretations and enabled us to establish the following biodegradation rules: (1) Target sites for amidohydrolases and for cytochrome P450 monooxygenases enhance biodegradation of nonaromatic N-heterocycles. (2) Target sites for molybdenum hydroxylases enhance biodegradation of aromatic N-heterocycles. (3) Target sites for hydratation by an urocanase-like mechanism enhance biodegradation of imidazoles. Our complementary approach represents a feasible strategy for generating concrete rules for the prediction of biodegradability of organic compounds.
Biodegradation and attenuation of steroidal hormones and alkylphenols by stream biofilms and sediments

Science.gov (United States)

Writer, Jeffrey; Barber, Larry B.; Ryan, Joseph N.; Bradley, Paul M.

2011-01-01

Biodegradation of select endocrine-disrupting compounds (17β-estradiol, estrone, 17α-ethynylestradiol, 4-nonylphenol, 4-nonylphenolmonoexthoylate, and 4-nonylphenoldiethoxylate) was evaluated in stream biofilm, sediment, and water matrices collected from locations upstream and downstream from a wastewater treatment plant effluent discharge. Both biologically mediated transformation to intermediate metabolites and biologically mediated mineralization were evaluated in separate time interval experiments. Initial time intervals (0–7 d) evaluated biodegradation by the microbial community dominant at the time of sampling. Later time intervals (70 and 185 d) evaluated the biodegradation potential as the microbial community adapted to the absence of outside energy sources. The sediment matrix was more effective than the biofilm and water matrices at biodegrading 4-nonylphenol and 17β-estradiol. Biodegradation by the sediment matrix of 17α-ethynylestradiol occurred at later time intervals (70 and 185 d) and was not observed in the biofilm or water matrices. Stream biofilms play an important role in the attenuation of endocrine-disrupting compounds in surface waters due to both biodegradation and sorption processes. Because sorption to stream biofilms and bed sediments occurs on a faster temporal scale (185 d), these compounds can accumulate in stream biofilms and sediments.
Slowly biodegradable organic compounds impact the biostability of non-chlorinated drinking water produced from surface water

NARCIS (Netherlands)

Hijnen, W.A.M.; Schurer, R.; Bahlman, J.A.; Ketelaars, H.A.M.; Italiaander, R.; Wal, van der A.; Wielen, van der P.W.J.J.

2018-01-01

It is possible to distribute drinking water without a disinfectant residual when the treated water is biologically stable. The objective of this study was to determine the impact of easily and slowly biodegradable compounds on the biostability of the drinking water at three full-scale production
Biodegradation of selected offshore chemicals

OpenAIRE

Wennberg, Aina C.; Petersen, Karina

2017-01-01

A review of biodegradation data for specific oil field chemicals and chemical groups were performed in order to evaluate if the current categorisation of these were appropriate based on the biodegradation properties. Data were compiled from databases like ECHA and MITI and from the literature. For compounds with limited or inconclusive test data, biodegradation was also estimated by the BIOWIN models, and the EAWAG-BBD pathway prediction system was used to predict plausible biodegradation pat...
Biodegradable Orthopedic Magnesium-Calcium (MgCa Alloys, Processing, and Corrosion Performance

Directory of Open Access Journals (Sweden)

Yuebin Guo

2012-01-01

Full Text Available Magnesium-Calcium (Mg-Ca alloy has received considerable attention as an emerging biodegradable implant material in orthopedic fixation applications. The biodegradable Mg-Ca alloys avoid stress shielding and secondary surgery inherent with permanent metallic implant materials. They also provide sufficient mechanical strength in load carrying applications as opposed to biopolymers. However, the key issue facing a biodegradable Mg-Ca implant is the fast corrosion in the human body environment. The ability to adjust degradation rate of Mg-Ca alloys is critical for the successful development of biodegradable orthopedic implants. This paper focuses on the functions and requirements of bone implants and critical issues of current implant biomaterials. Microstructures and mechanical properties of Mg-Ca alloys, and the unique properties of novel magnesium-calcium implant materials have been reviewed. Various manufacturing techniques to process Mg-Ca based alloys have been analyzed regarding their impacts on implant performance. Corrosion performance of Mg-Ca alloys processed by different manufacturing techniques was compared. In addition, the societal and economical impacts of developing biodegradable orthopedic implants have been emphasized.
INFLUENCE OF INORGANIC COMPOUNDS ON THE PROCESS OF PHOTOCATALYSIS OF BIOLOGICALLY ACTIVE COMPOUNDS

Directory of Open Access Journals (Sweden)

Edyta Kudlek

2017-07-01

Full Text Available Constant increase in concentration of organic micropollutants in the water environment influences the development of methods for their effective elimination from various matrices released into aquatic ecosystems. One of widely described in literature processes for the decomposition of hardly-biodegradable pollutants is the process of heterogeneous photocatalysis. The paper presents the influence of inorganic substances on the decomposition of polycyclic aromatic hydrocarbons (anthracene and benzo[a]pyrene, industrial admixtures - octylphenol and pharmaceutical compounds - diclofenac in the photocatalysis process conducted in the presence of TiO2. It has been shown that the presence of Cl- ions did not affect the photochemical reaction of the micropollutant decomposition. Whereas, the presence of CO3(2-, SO4(2- and HPO4(2- ions inhibited the decolonization of octylphenol and diclofenac, while the degradation efficiency of anthracene and benzo[a]pyrene was reduced only by the presence of CO3(2- and HCO3- anions. The photooxidation of micropollutants in solutions containing Al(3+ oraz Fe(3+ cations proceeded with a much lower efficiency than that for solution without inorganic compounds. The analysis of the kinetics of the photocatalytic decomposition of selected micropollutants show a decrease in the reaction rate constant and an increase in their half-life due to the blocking of theactive semiconductor centers by inorganic compounds. In addition,the toxicological analysis inducated the generation of micropollutant oxidation by-products, which aggravate the quality of treated aqueous solutions.
Toxicological evaluation of vegetable oils and biodiesel in soil during the biodegradation process

Directory of Open Access Journals (Sweden)

Ivo S. Tamada

2012-12-01

Full Text Available Vegetable oils and their derivatives, like biodiesel, are used extensively throughout the world, thus posing an environmental risk when disposed. Toxicity testing using test organisms shows how these residues affect ecosystems. Toxicity tests using earthworms (Eisenia foetida. are widespread because they are a practical resource for analyzing terrestrial organisms. For phytotoxicological analysis, we used seeds of arugula (Eruca sativa and lettuce (Lactuca sativa. to analyze the germination of seeds in contaminated soil samples. The toxicological experiment was conducted with four different periods of biodegradation in soil: zero days, 60 days, 120 days and 180 days. The studied contaminants were soybean oil (new and used and biodiesel (B100. An evaluation of the germination of both seeds showed an increased toxicity for all contaminants as the biodegradation occurred, biodiesel being the most toxic among the contaminants. On the other hand, for the tests using earthworms, the biodiesel was the only contaminant that proved to be toxic. Therefore, the higher toxicity of the sample containing these hydrocarbons over time can be attributed to the secondary compounds formed by microbial action. Thus, we conclude that the biodegradation in soil of the studied compounds requires longer periods for the sample toxicity to be decreased with the action of microorganisms.
Biodegradable alternative for removing toxic compounds from sugarcane bagasse hemicellulosic hydrolysates for valorization in biorefineries.

Science.gov (United States)

Silva-Fernandes, T; Santos, J C; Hasmann, F; Rodrigues, R C L B; Izario Filho, H J; Felipe, M G A

2017-11-01

Among the major challenges for hemicellulosic hydrolysate application in fermentative processes, there is the presence of toxic compounds generated during the pretreatment of the biomass, which can inhibit microbial growth. Therefore, the development of efficient, biodegradable and cost-effective detoxification methods for lignocellulosic hydrolysates is crucial. In this work, two tannin-based biopolymers (called A and B) were tested in the detoxification of sugarcane bagasse hydrolysate for subsequent fermentation by Candida guilliermondii. The effects of biopolymer concentration, pH, temperature, and contact time were studied using a 2 4 experimental design for both biopolymers. Results revealed that the biopolymer concentration and the pH were the most significant factors in the detoxification step. Biopolymer A removed phenolics, 5-hydroxymethylfurfural, and nickel from the hydrolysate more efficiently than biopolymer B, while biopolymer B was efficient to remove chromium at 15% (v/v). Detoxification enhanced the fermentation of sugarcane bagasse hydrolysate, and the biopolymers showed different influences on the process. Copyright © 2017 Elsevier Ltd. All rights reserved.
Processing and Properties of PCL/Cotton Linter Compounds

OpenAIRE

Bezerra,Elieber Barros; França,Danyelle Campos; Morais,Dayanne Diniz de Souza; Rosa,Morsyleide de Freitas; Morais,João Paulo Saraiva; Araújo,Edcleide Maria; Wellen,Renate Maria Ramos

2017-01-01

Biodegradable compounds of poly(ε-caprolactone) (PCL)/ cotton linter were melting mixed with filling content ranging from 1% to 5% w/w. Cotton linter is an important byproduct of textile industry; in this work it was used in raw state and after acid hydrolysis. According to the results of torque rheometry no decaying of viscosity took place during compounding, evidencing absence of breaking down in molecular weight. The thermal stability increased by 20% as observed in HDT for PCL/cotton...
Reinterpreting the importance of oxygen-based biodegradation in chloroethene-contaminated groundwater

Science.gov (United States)

Bradley, Paul M.

2011-01-01

Chlororespiration is common in shallow aquifer systems under conditions nominally identified as anoxic. Consequently, chlororespiration is a key component of remediation at many chloroethene-contaminated sites. In some instances, limited accumulation of reductive dechlorination daughter products is interpreted as evidence that natural attenuation is not adequate for site remediation. This conclusion is justified when evidence for parent compound (tetrachloroethene, PCE, or trichloroethene, TCE) degradation is lacking. For many chloroethene-contaminated shallow aquifer systems, however, nonconservative losses of the parent compounds are clear but the mass balance between parent compound attenuation and accumulation of reductive dechlorination daughter products is incomplete. Incomplete mass balance indicates a failure to account for important contaminant attenuation mechanisms and is consistent with contaminant degradation to nondiagnostic mineralization products like CO2. While anoxic mineralization of chloroethene compounds has been proposed previously, recent results suggest that oxygen-based mineralization of chloroethenes also can be significant at dissolved oxygen concentrations below the currently accepted field standard for nominally anoxic conditions. Thus, reassessment of the role and potential importance of low concentrations of oxygen in chloroethene biodegradation are needed, because mischaracterization of operant biodegradation processes can lead to expensive and ineffective remedial actions. A modified interpretive framework is provided for assessing the potential for chloroethene biodegradation under different redox conditions and the probable role of oxygen in chloroethene biodegradation.
Characterization of phenols biodegradation by compound specific stable isotope analysis

Science.gov (United States)

Wei, Xi; Gilevska, Tetyana; Wenzig, Felix; Hans, Richnow; Vogt, Carsten

2015-04-01

Biodegradation of phenol and alkylphenols has been described under both oxic and anoxic conditions. In the absence of molecular oxygen, the degradation of phenolic compounds is initiated by microorganisms through carboxylation, fumarate addition to the methyl moiety or anoxic hydroxylation of the methyl moiety. Comparatively, under aerobic condition, the initiation mechanisms are revealed to be monoxygenation or dihydroxylation for phenol and ring hydroxylation or methyl group oxidation for cresols. While several studies biochemically characterized the enzymes and reaction mechanisms in the relevant degradation pathways, isotope fractionation patterns were rarely reported possibly due to constraints in current analytical methods. In this study, the carbon isotope fractionation patterns upon the degradation of phenol and cresols by several strains were analyzed by using isotope ratio mass spectrometry connected with liquid chromatography (LC-IRMS). The corresponding enrichment factors for carbon (ƐC) have been obtained. Cresols degradation by various strains showed generally moderate carbon isotope fractionation patterns with notable differences. For p-cresol degradation, five strains were examined. The aerobic strain Acinetobacter calcoaceticus NCIMB8250 exploits ring hydroxylation by molecular oxygen as initial reaction, and a ƐC value of -1.4±0.2‰ was obtained. Pseudomonas pseudoalcaligenes NCIMB 9867, an aerobic strain initiating cresols degradation via oxygen-dependent side chain hydroxylation, yielded a ƐC value of -2.3±0.2‰. Under nitrate-reducing conditions, Geobacter metallireducens DSM 7210 and Azoarcus buckelii DSM 14744 attacks p-cresol at the side chain by monohydroxylation using water as oxygen source; the two strains produced ƐC values of -3.6±0.4‰ and -2±0.1‰, accordingly. The sulfate-reducing Desulfosarcina cetonica DSM 7267 activating cresols by fumarate addition to the methyl moiety yielded ƐC values of -1.9±0.2‰ for p
Oxidant reduction and biodegradability improvement of paper mill effluent by irradiation

International Nuclear Information System (INIS)

Tiezheng Wang; Waite, T.D.; Kurucz, C.

1994-01-01

Paper mill bleach processing wastewaters represent a large input of hazardous compounds to the environment and these compounds are usually non-biodegradable. A preliminary study using a 5000 Ci 60 Co gamma radiation source as a surrogate for electron beam irradiation, potentially an emerging technology for wastewater treatment, to treat a paper mill bleach effluent showed that for an absorbed dose of 800 krads, chemical oxygen demand (COD) was reduced by 13.5% and 5 day biochemical oxygen demand (BOD 5 ) was increased 58.6%. These changes altered the value of COD/BOD 5 from 14 to 5. For the same dose, the absorbable organic halogen (AOX) was reduced 76.2%. These results suggested the possibility of using the electron beam process to detoxify paper mill effluent thereby generating a more biodegradable wastewater. (author)
Bioavailability of Heavy Metals in Soil: Impact on Microbial Biodegradation of Organic Compounds and Possible Improvement Strategies

Science.gov (United States)

Olaniran, Ademola O.; Balgobind, Adhika; Pillay, Balakrishna

2013-01-01

Co-contamination of the environment with toxic chlorinated organic and heavy metal pollutants is one of the major problems facing industrialized nations today. Heavy metals may inhibit biodegradation of chlorinated organics by interacting with enzymes directly involved in biodegradation or those involved in general metabolism. Predictions of metal toxicity effects on organic pollutant biodegradation in co-contaminated soil and water environments is difficult since heavy metals may be present in a variety of chemical and physical forms. Recent advances in bioremediation of co-contaminated environments have focussed on the use of metal-resistant bacteria (cell and gene bioaugmentation), treatment amendments, clay minerals and chelating agents to reduce bioavailable heavy metal concentrations. Phytoremediation has also shown promise as an emerging alternative clean-up technology for co-contaminated environments. However, despite various investigations, in both aerobic and anaerobic systems, demonstrating that metal toxicity hampers the biodegradation of the organic component, a paucity of information exists in this area of research. Therefore, in this review, we discuss the problems associated with the degradation of chlorinated organics in co-contaminated environments, owing to metal toxicity and shed light on possible improvement strategies for effective bioremediation of sites co-contaminated with chlorinated organic compounds and heavy metals. PMID:23676353
Bioavailability of Heavy Metals in Soil: Impact on Microbial Biodegradation of Organic Compounds and Possible Improvement Strategies

Directory of Open Access Journals (Sweden)

Balakrishna Pillay

2013-05-01

Full Text Available Co-contamination of the environment with toxic chlorinated organic and heavy metal pollutants is one of the major problems facing industrialized nations today. Heavy metals may inhibit biodegradation of chlorinated organics by interacting with enzymes directly involved in biodegradation or those involved in general metabolism. Predictions of metal toxicity effects on organic pollutant biodegradation in co-contaminated soil and water environments is difficult since heavy metals may be present in a variety of chemical and physical forms. Recent advances in bioremediation of co-contaminated environments have focussed on the use of metal-resistant bacteria (cell and gene bioaugmentation, treatment amendments, clay minerals and chelating agents to reduce bioavailable heavy metal concentrations. Phytoremediation has also shown promise as an emerging alternative clean-up technology for co-contaminated environments. However, despite various investigations, in both aerobic and anaerobic systems, demonstrating that metal toxicity hampers the biodegradation of the organic component, a paucity of information exists in this area of research. Therefore, in this review, we discuss the problems associated with the degradation of chlorinated organics in co-contaminated environments, owing to metal toxicity and shed light on possible improvement strategies for effective bioremediation of sites co-contaminated with chlorinated organic compounds and heavy metals.
Field demonstration of natural biodegradation of BTEX compounds

International Nuclear Information System (INIS)

Borden, R.C.; Davis, C.W.; LeBrun, L.E. IV

1993-01-01

An extensive field study is being conducted at an underground storage tank (UST) release in Sampson Co., NC to aid in understanding the physical, chemical and biological processes controlling the rate and extent of natural bioremediation. Uncontaminated groundwater at the site contains roughly 5 mg/l dissolved oxygen and 15 mg/l nitrate as N. Although the USTs and some soil were removed, much of the NAPL contaminated soil could not be excavated and remains behind as a continuing source of dissolved BTEX. The NAPL gasoline in the subsurface has been naturally biodegrading for several years. Because of the low ground water velocity and high levels of contamination, bioremediation is not yet complete but the effects of oxygen and nitrates enhanced bioremediation are evident. Toluene, ethylbenzene, m + p-xylene and to a lesser extent o-xylene are rapidly removed in a zone less than 125 ft (40 m) wide immediately downgradient from the NAPL source area. A long narrow plume of dissolved benzene and MTBE persists and is migrating downgradient towards a small creek. Biodegradation of the benzene plume appears to be limited by diffusion of oxygen into the anoxic plume. In aerobic microcosms, all BTEX components were rapidly removed to below detection. Toluene and ethylbenzene were removed to below 10 ug/l in the denitrifying microcosms after an extended lag period
Two-dimensional flow-through microcosms - Versatile test systems to study biodegradation processes in porous aquifers

Science.gov (United States)

Bauer, Robert D.; Rolle, Massimo; Kürzinger, Petra; Grathwohl, Peter; Meckenstock, Rainer U.; Griebler, Christian

2009-05-01

SummaryA fundamental prerequisite of any remedial activity is a sound knowledge of both the biotic and abiotic processes involved in transport and degradation of contaminants. Investigations of these aspects in situ often seem infeasible due to the complexity of interacting processes. A simplified portrayal of nature can be facilitated in laboratory-based two-dimensional (2D) sediment flow-through microcosms. This paper describes the versatility of such simple aquifer model systems with respect to biodegradation of aromatic hydrocarbons, i.e. toluene and ethylbenzene, under various environmental conditions. Initially constructed to study non-reactive and bioreactive transport of organic contaminants in homogeneous porous media under steady state hydraulic conditions, experimental setups developed towards more realistic heterogeneous sediment packing and transient hydraulic conditions. High-resolution spatial and temporal sampling allowed to obtain new insights on the distribution of bioactivities in contaminant plumes and associated controlling and limiting factors. Major biodegradation activities in saturated porous sediments are located at the fringes of contaminant plumes and are driven by dispersive mixing. These hot-spots of contaminant biotransformation are characterized by steep physical-chemical gradients in the millimeter to centimeter range. Sediment heterogeneity, i.e. high-conductivity zones, was shown to significantly enhance transverse mixing and subsequently biodegradation. On the contrary, transient hydraulic conditions may generate intermediate disturbances to biodegrader populations and thus may interfere with optimized contaminant conversion. However, a bacterial strain aerobically degrading toluene, i.e. Pseudomonas putida F1, was shown to adapt to vertically moving contaminant plumes, in the way that it regained full biodegradation potential two-times faster in areas with a mid-term (days to weeks) contamination history than in areas not
Monitoring biodegradation of diesel fuel in bioventing processes using in situ respiration rate.

Science.gov (United States)

Lee, T H; Byun, I G; Kim, Y O; Hwang, I S; Park, T J

2006-01-01

An in situ measuring system of respiration rate was applied for monitoring biodegradation of diesel fuel in a bioventing process for bioremediation of diesel contaminated soil. Two laboratory-scale soil columns were packed with 5 kg of soil that was artificially contaminated by diesel fuel as final TPH (total petroleum hydrocarbon) concentration of 8,000 mg/kg soil. Nutrient was added to make a relative concentration of C:N:P = 100:10:1. One soil column was operated with continuous venting mode, and the other one with intermittent (6 h venting/6 h rest) venting mode. On-line O2 and CO2 gas measuring system was applied to measure O2 utilisation and CO2 production during biodegradation of diesel for 5 months. Biodegradation rate of TPH was calculated from respiration rate measured by the on-line gas measuring system. There were no apparent differences between calculated biodegradation rates from two columns with different venting modes. The variation of biodegradation rates corresponded well with trend of the remaining TPH concentrations comparing other biodegradation indicators, such as C17/pristane and C18/phytane ratio, dehydrogenase activity, and the ratio of hydrocarbon utilising bacteria to total heterotrophic bacteria. These results suggested that the on-line measuring system of respiration rate would be applied to monitoring biodegradation rate and to determine the potential applicability of bioventing process for bioremediation of oil contaminated soil.

Anaerobic biodegradation of halogenated and nonhalogenated N-, s-, and o-heterocyclic compounds in aquifer slurries

Science.gov (United States)

Adrian, Neal R.; Suflita, Joseph M.

1994-01-01

The fate of several halogenated and nonhalogenated heterocyclic compounds in anoxic aquifer slurries was investigated Substrate depletion and methane formation were monitored in serum bottle incubations by HPLC and GC, respectively Pyridine, pyrimidine, thiophene, and furan were not mineralized following an 11-month incubation, but the corresponding carboxylated or oxygenated compounds were That is, >74% of the theoretically expected amount of methane was recovered from nicotinic acid, uracil, or 2-furoic acid Chlorinated derivatives, like 2 chloro- or 6-chloronicotinic acid, as well as 4 chloro- and 5-chlorouracil resisted mineralization However, 5-bromouracil was reductively dehalogenated to stoichiometric amounts of uracil, whereas 2-chloropyrimidine was metabolized to a more polar unidentified compound that resisted further anaerobic biodegradation Microorganisms acclimated to 5-bromouracil were unable to transform 4 chloro or 5 chlorouracil These findings illustrate how the structure of heterocyclic contaminants influences their susceptibility to anaerobic decay
Biodegrader metabolic expansion during polyaromatic hydrocarbons rhizoremediation

Energy Technology Data Exchange (ETDEWEB)

Rugh, C.L.; Susilawati, E.; Kravchenko, A.N. [Dept. of Crop and Soil Sciences, Michigan State Univ., East Lansing, MI (United States); Thomas, J.C. [Dept. of Natural Sciences, Univ. of Michigan-Dearborn, Dearborn, MI (United States)

2005-04-01

Root-microbe interactions are considered to be the primary process of polyaromatic hydrocarbon (PAH) phytoremediation, since bacterial degradation has been shown to be the dominant pathway for environmental PAH dissipation. However, the precise mechanisms driving PAH rhizostimulation symbiosis remain largely unresolved. In this study, we assessed PAH degrading bacterial abundance in contaminated soils planted with 18 different native Michigan plant species. Phenanthrene metabolism assays suggested that each plant species differentially influenced the relative abundance of PAH biodegraders, though they generally were observed to increase heterotrophic and biodegradative cell numbers relative to unplanted soils. Further study of > 1800 phenanthrene degrading isolates indicated that most of the tested plant species stimulated biodegradation of a broader range of PAH compounds relative to the unplanted soil bacterial consortia. These observations suggest that a principal contribution of planted systems for PAH bioremediation may be via expanded metabolic range of the rhizosphere bacterial community. (orig.)
Biodegradation of naphthalene from nonaqueous-phase liquids

International Nuclear Information System (INIS)

Ghoshal, S.; Luthy, R.G.; Ramaswami, A.

1995-01-01

Dissolution of polycyclic aromatic hydrocarbons (PAHs) from a non-aqueous-phase liquid (NAPL) to the aqueous phase renders these compounds bioavailable to microorganisms. Subsequent biodegradation of organic phase PAH then results in a depletion of PAH from the NAPL. This study focuses on identifying the rate-controlling processes affecting naphthalene biomineralization from a complex multicomponent NAPL, coal tar, and a simple two-component NAPL. A simplified dissolution degradation model is presented to identify quantitative criteria to assess whether mass transfer or biokinetic limitations control the overall rate of biotransformation of PAH compounds. Results show that the rate of mass transfer may control the overall rate of biotransformation in certain systems. Mass transfer does not limit biodegradation in slurry systems when coal tar is distributed in the micropores of a large number of small microporous silica particles. The end points of naphthalene degradation from the NAPLs have been evaluated, and results suggest that depletion of a significant mass of naphthalene from the NAPL phase is possible
Effects of iron type in Fenton reaction on mineralization and biodegradability enhancement of hazardous organic compounds.

Science.gov (United States)

Khan, Eakalak; Wirojanagud, Wanpen; Sermsai, Nawarat

2009-01-30

The mineralization and biodegradability increase and their combination of two traditional and two relatively new organic contaminants by Fenton reagents with three different types of iron, Fe(2+), Fe(3+), and Fe(0) were investigated. The traditional contaminants examined were trichloroethene (TCE) and 2,4-dichlorophenol (2,4-DCP) while 1,4-dioxane (1,4-D) and 1,2,3-trichloropropane (TCP) were studied for the relatively new contaminants. The mineralization and biodegradability were represented by dissolved organic carbon (DOC) reduction and the ratio of biodegradable dissolved organic carbon and DOC, respectively. For all four contaminants, Fenton reagent using Fe(2+) was more effective in the DOC reduction than Fenton reagents using Fe(3+) and Fe(0) in most cases. The types of Fe that provided maximum biodegradability increase were not the same for all four compounds, Fe(3+) for TCE, Fe(0) for 2,4-DCP, Fe(2+) for 1,4-D, and Fe(3+) for TCP. When the combination of DOC elimination and biodegradability increase (least refractory fraction) was considered, Fe(2+) was the best choice except for 2,4-DCP which was susceptible to Fe(0) catalyzed Fenton reagent the most. The least refractory fractions remaining after 120 min of reaction were 20-25% for TCE, 2,4-DCP, and TCP and 30-40% for 1,4-D. The iron type in Fenton reaction also affected the type of mineralization kinetics of TCE, 2,4-DCP, and TCP as well as the types of degradation by-products of these contaminants. Some of the by-products found, such as isopropanol and propionic aldehyde, which were produced from Fe(0) catalyzed Fenton degradation of TCP, have not been previously reported.
Saponification of fatty slaughterhouse wastes for enhancing anaerobic biodegradability.

Science.gov (United States)

Battimelli, Audrey; Carrère, Hélène; Delgenès, Jean-Philippe

2009-08-01

The thermochemical pretreatment by saponification of two kinds of fatty slaughterhouse waste--aeroflotation fats and flesh fats from animal carcasses--was studied in order to improve the waste's anaerobic degradation. The effect of an easily biodegradable compound, ethanol, on raw waste biodegradation was also examined. The aims of the study were to enhance the methanisation of fatty waste and also to show a link between biodegradability and bio-availability. The anaerobic digestion of raw waste, saponified waste and waste with a co-substrate was carried out in batch mode under mesophilic and thermophilic conditions. The results showed little increase in the total volume of biogas, indicating a good biodegradability of the raw wastes. Mean biogas volume reached 1200 mL/g VS which represented more than 90% of the maximal theoretical biogas potential. Raw fatty wastes were slowly biodegraded whereas pretreated wastes showed improved initial reaction kinetics, indicating a better initial bio-availability, particularly for mesophilic runs. The effects observed for raw wastes with ethanol as co-substrate depended on the process temperature: in mesophilic conditions, an initial improvement was observed whereas in thermophilic conditions a significant decrease in biodegradability was observed.
Aerobic biodegradation of a nonylphenol polyethoxylate and toxicity of the biodegradation metabolites.

Science.gov (United States)

Jurado, Encarnación; Fernández-Serrano, Mercedes; Núñez-Olea, Josefa; Lechuga, Manuela

2009-09-01

In this paper a study was made of the biodegradation of a non-ionic surfactant, a nonylphenol polyethoxylate, in biodegradability tests by monitoring the residual surfactant matter. The influence of the concentration on the extent of primary biodegradation, the toxicity of biodegradation metabolites, and the kinetics of degradation were also determined. The primary biodegradation was studied at different initial concentrations: 5, 25 and 50 mg/L, (at sub-and supra-critical micelle concentration). The NPEO used in this study can be considered biodegradable since the primary biodegradation had already taken place (a biodegradation greater than 80% was found for the different initial concentration tested). The initial concentration affected the shape of the resulting curve, the mean biodegradation rate and the percentage of biodegradation reached (99% in less than 8 days at 5 mg/L, 98% in less than 13 days at 25 mg/L and 95% in 14 days at 50 mg/L). The kinetic model of Quiroga and Sales (1991) was applied to predict the biodegradation of the NPEO. The toxicity value was measured as EC(20) and EC(50). In addition, during the biodegradation process of the surfactant a toxicity analysis was made of the evolution of metabolites generated, confirming that the subproducts of the biodegradation process were more toxic than the original.
Water quality - Evaluation of the aerobic biodegradability of organic compounds at low concentrations. Part 1: Shake-flask batch test with surface water or suface water/sediment suspensions. ISO 14592-1

DEFF Research Database (Denmark)

Nyholm, Niels; Pagga, U.

ISO 14592-1:2002 specifies a test method for evaluating the biodegradability of organic test compounds by aerobic microorganisms in surface waters by means of a shake-flask batch test with suspended biomass. It is applicable to natural surface water, free from coarse particles to simulate a pelagic...... compounds present in lower concentrations (normally below 100 micrograms per litre) than those of natural carbon substrates also present in the system. Under these conditions, the test compounds serve as a secondary substrate and the kinetics for biodegradation would be expected to be first order (non......-growth kinetics). This test method is not recommended for use as proof of ultimate biodegradation which is better assessed using other standardized tests. It is also not applicable to studies on metabolite formation and accumulation which require higher test concentrations....
Intimately coupling of photolysis accelerates nitrobenzene biodegradation, but sequential coupling slows biodegradation

Energy Technology Data Exchange (ETDEWEB)

Yang, Lihui [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Zhang, Yongming, E-mail: zhym@shnu.edu.cn [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Bai, Qi; Yan, Ning; Xu, Hua [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Rittmann, Bruce E. [Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, Tempe, AZ 85287-5701 (United States)

2015-04-28

Highlights: • Intimately coupled UV photolysis accelerated nitrobenzene biodegradation. • NB biodegradation was slowed by accumulation of nitrophenol. • Oxalic acid was a key product of UV photolysis. • Oxalic acid accelerated biodegradation of nitrobenzene and nitrophenol by a co-substrate effect. • Intimate coupling of UV and biodegradation accentuated the benefits of oxalic acid. - Abstract: Photo(cata)lysis coupled with biodegradation is superior to photo(cata)lysis or biodegradation alone for removal of recalcitrant organic compounds. The two steps can be carried out sequentially or simultaneously via intimate coupling. We studied nitrobenzene (NB) removal and mineralization to evaluate why intimate coupling of photolysis with biodegradation was superior to sequential coupling. Employing an internal circulation baffled biofilm reactor, we compared direct biodegradation (B), biodegradation after photolysis (P + B), simultaneous photolysis and biodegradation (P&B), and biodegradation with nitrophenol (NP) and oxalic acid (OA) added individually and simultaneously (B + NP, B + OA, and B + NP + OA); NP and OA were NB’s main UV-photolysis products. Compared with B, the biodegradation rate P + B was lower by 13–29%, but intimately coupling (P&B) had a removal rate that was 10–13% higher; mineralization showed similar trends. B + OA gave results similar to P&B, B + NP gave results similar to P + B, and B + OA + NP gave results between P + B and P&B, depending on the amount of OA and NP added. The photolysis product OA accelerated NB biodegradation through a co-substrate effect, but NP was inhibitory. Although decreasing the UV photolysis time could minimize the inhibition impact of NP in P + B, P&B gave the fastest removal of NB by accentuating the co-substrate effect of OA.
Intimately coupling of photolysis accelerates nitrobenzene biodegradation, but sequential coupling slows biodegradation

International Nuclear Information System (INIS)

Yang, Lihui; Zhang, Yongming; Bai, Qi; Yan, Ning; Xu, Hua; Rittmann, Bruce E.

2015-01-01

Highlights: • Intimately coupled UV photolysis accelerated nitrobenzene biodegradation. • NB biodegradation was slowed by accumulation of nitrophenol. • Oxalic acid was a key product of UV photolysis. • Oxalic acid accelerated biodegradation of nitrobenzene and nitrophenol by a co-substrate effect. • Intimate coupling of UV and biodegradation accentuated the benefits of oxalic acid. - Abstract: Photo(cata)lysis coupled with biodegradation is superior to photo(cata)lysis or biodegradation alone for removal of recalcitrant organic compounds. The two steps can be carried out sequentially or simultaneously via intimate coupling. We studied nitrobenzene (NB) removal and mineralization to evaluate why intimate coupling of photolysis with biodegradation was superior to sequential coupling. Employing an internal circulation baffled biofilm reactor, we compared direct biodegradation (B), biodegradation after photolysis (P + B), simultaneous photolysis and biodegradation (P&B), and biodegradation with nitrophenol (NP) and oxalic acid (OA) added individually and simultaneously (B + NP, B + OA, and B + NP + OA); NP and OA were NB’s main UV-photolysis products. Compared with B, the biodegradation rate P + B was lower by 13–29%, but intimately coupling (P&B) had a removal rate that was 10–13% higher; mineralization showed similar trends. B + OA gave results similar to P&B, B + NP gave results similar to P + B, and B + OA + NP gave results between P + B and P&B, depending on the amount of OA and NP added. The photolysis product OA accelerated NB biodegradation through a co-substrate effect, but NP was inhibitory. Although decreasing the UV photolysis time could minimize the inhibition impact of NP in P + B, P&B gave the fastest removal of NB by accentuating the co-substrate effect of OA
A critical comparison of respirometric biodegradation tests based on OECD 301 and related test methods.

Science.gov (United States)

Reuschenbach, Peter; Pagga, Udo; Strotmann, Uwe

2003-04-01

Biodegradation studies of organic compounds in the aquatic environment gain important information for the final fate of chemicals in the environment. A decisive role play tests for ready biodegradability (OECD 301) and in this context, the respirometric test (OECD 301F). Two different respirometric systems (Oxitop and Sapromat) were compared and in two of ten cases (diethylene glycol and 2-ethylhexylacrylate) differences were observed indicating that the test systems are not always equivalent. For 2-ethylhexylacrylate and cyclohexanone we could not state differences in the extent of biodegradation with a municipal and industrial inoculum whereas for cyclohexanone the degradation rate was faster with a municipal inoculum. Allylthiourea (ATU) proved to be an effective inhibitor of nitrification processes and did not affect the heterotrophic biodegradation activity. Modelling of biodegradation processes could be successfully performed with a first-order and a modified logistic plot. Copyright 2002 Elsevier Science Ltd.
Process for in-situ biodegradation of hydrocarbon contaminated soil

International Nuclear Information System (INIS)

Ely, D.L.; Heffner, D.A.

1991-01-01

This patent describes an in situ process for biodegrading hydrocarbons by drawing oxygen into an undisturbed hydrocarbon contaminated zone in a fluid permeable soil. It comprises: establishing a borehole extending from the earth's surface through a hydrocarbon contaminated zone having hydrocarbon degrading microbes therein; lining the borehole with a fluid impermeable liner coaxially spaced and sealingly connected to the inside surface of the borehole and extending from the earth's surface to the hydrocarbon-contaminated zone; the liner including a fluid permeable portion extending from the lower end thereof and through at least a portion of the hydrocarbon contaminated zone, fluidly connecting a source of negative pressure to the fluid impermeable line; evacuating gas from the borehole through the fluid permeable portion of the liner at a rate sufficient to draw air from the earth's surface into the hydrocarbon containing zone; and adjusting the flow rate of the evacuated gas so that the amount of hydrocarbon biodegradation therein is within 50% of the maximum hydrocarbon biodegradation rate as detected by the volume of carbon dioxide in the evacuated gas
FINASOL OSR 51 biodegradation by the biological activators BIOLEN IG 30 and BIOLEN IC 10

Energy Technology Data Exchange (ETDEWEB)

Bergueiro, J.R.; Dominguez, F.; Guzman, E. [Balearic Island Univ., Palma de Mallorca, Islas Baleares (Spain); Morales, N. [Alfonso X El Sabio Univ., Madrid (Spain); Perez-Navarro, A. [LAESA, Zaragoza (Spain)

1998-09-01

Results of experimental work to study the biodegradation of the total ionic and anionic dispersants in FINASOL OSR 51 for the biological activators BIOLEN IG 30 and IC 10 were described. BIOLEN IG 30 and IC 10 are mixtures of bacteria chosen for their ability to degrade a wide range of chemical compounds. Biodegradation experiments were conducted in a non-isothermal container at room temperature (between 16.9 and 30.8 degrees C) to simulate the biodegradation process in a natural environment where the temperature cannot be controlled. Additional experiments were conducted at a controlled temperature value of 20 degrees C. Eight different reactor tests were performed with FINASOL OSR 51 dispersed in distilled and sterilized water. The influence of the accelerator INIPOL EAP 22 on the degradation process was also examined. Results from the degradation of the different compounds were presented and their kinetic coefficients were calculated. Biological Oxygen Demand at five days and at the end of the degradation was also determined. This made it possible to calculate the biodegradation constant and the biochemical stabilization constant. 11 refs., 13 tabs., 8 figs.
Biodegradability of plastics.

Science.gov (United States)

Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

2009-08-26

Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.
Reactive transport modeling of processes controlling the distribution and natural attenuation of phenolic compounds in a deep sandstone aquifer

Science.gov (United States)

Mayer, K. U.; Benner, S. G.; Frind, E. O.; Thornton, S. F.; Lerner, D. N.

2001-12-01

Reactive solute transport modeling was utilized to evaluate the potential for natural attenuation of a contaminant plume containing phenolic compounds at a chemical producer in the West Midlands, UK. The reactive transport simulations consider microbially mediated biodegradation of the phenolic compounds (phenols, cresols, and xylenols) by multiple electron acceptors. Inorganic reactions including hydrolysis, aqueous complexation, dissolution of primary minerals, formation of secondary mineral phases, and ion exchange are considered. One-dimensional (1D) and three-dimensional (3D) simulations were conducted. Mass balance calculations indicate that biodegradation in the saturated zone has degraded approximately 1-5% of the organic contaminant plume over a time period of 47 years. Simulations indicate that denitrification is the most significant degradation process, accounting for approximately 50% of the organic contaminant removal, followed by sulfate reduction and fermentation reactions, each contributing 15-20%. Aerobic respiration accounts for less than 10% of the observed contaminant removal in the saturated zone. Although concentrations of Fe(III) and Mn(IV) mineral phases are high in the aquifer sediment, reductive dissolution is limited, producing only 5% of the observed mass loss. Mass balance calculations suggest that no more than 20-25% of the observed total inorganic carbon (TIC) was generated from biodegradation reactions in the saturated zone. Simulations indicate that aerobic biodegradation in the unsaturated zone, before the contaminant entered the aquifer, may have produced the majority of the TIC observed in the plume. Because long-term degradation is limited to processes within the saturated zone, use of observed TIC concentrations to predict the future natural attenuation may overestimate contaminant degradation by a factor of 4-5.
Evaluation of ethyl tert-butyl ether biodegradation in a contaminated aquifer by compound-specific isotope analysis and in situ microcosms

Energy Technology Data Exchange (ETDEWEB)

Bombach, Petra, E-mail: petra.bombach@ufz.de [UFZ – Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig (Germany); Isodetect GmbH Leipzig, Deutscher Platz 5b, D-04103 Leipzig (Germany); Nägele, Norbert [Kuvier the Biotech Company S.L., Ctra. N-I, p.k. 234–P.E. INBISA 23" a, E-09001 Burgos (Spain); Rosell, Mònica [UFZ – Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig (Germany); Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristallografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), C/Martí i Franquès s/n, 08028 Barcelona (Spain); Richnow, Hans H. [UFZ – Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstrasse 15, D-04318 Leipzig (Germany); Fischer, Anko [Isodetect GmbH Leipzig, Deutscher Platz 5b, D-04103 Leipzig (Germany)

2015-04-09

Highlights: • In situ biodegradation of ETBE was investigated in a fuel contaminated aquifer. • Degradation was studied by CSIA and in situ microcosms in combination with TLFA-SIP. • ETBE was degraded when ETBE was the main groundwater contaminant. • ETBE was also degraded in the presence of BTEX and MTBE. • Hydrochemical analysis indicated aerobic and anaerobic ETBE biodegradation. - Abstract: Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental fate has been less investigated, thus far. In the present study, we investigated the in situ biodegradation of ETBE in a fuel-contaminated aquifer using compound-specific stable isotope analysis (CSIA), and in situ microcosms in combination with total lipid fatty acid (TLFA)-stable isotope probing (SIP). In a first field investigation, CSIA revealed insignificant carbon isotope fractionation, but low hydrogen isotope fractionation of up to +14‰ along the prevailing anoxic ETBE plume suggesting biodegradation of ETBE. Ten months later, oxygen injection was conducted to enhance the biodegradation of petroleum hydrocarbons (PH) at the field site. Within the framework of this remediation measure, in situ microcosms loaded with [{sup 13}C{sub 6}]-ETBE (BACTRAP{sup ®}s) were exposed for 119 days in selected groundwater wells to assess the biodegradation of ETBE by TLFA-SIP under the following conditions: (i) ETBE as main contaminant; (ii) ETBE as main contaminant subjected to oxygen injection; (iii) ETBE plus other PH; (iv) ETBE plus other PH subjected to oxygen injection. Under all conditions investigated, significant {sup 13}C-incorporation into microbial total lipid fatty acids extracted from the in situ microcosms was found, providing clear evidence of ETBE biodegradation.
Evaluation of ethyl tert-butyl ether biodegradation in a contaminated aquifer by compound-specific isotope analysis and in situ microcosms

International Nuclear Information System (INIS)

Bombach, Petra; a, E-09001 Burgos (Spain))" data-affiliation=" (Kuvier the Biotech Company S.L., Ctra. N-I, p.k. 234–P.E. INBISA 23a, E-09001 Burgos (Spain))" >Nägele, Norbert; Rosell, Mònica; Richnow, Hans H.; Fischer, Anko

2015-01-01

Highlights: • In situ biodegradation of ETBE was investigated in a fuel contaminated aquifer. • Degradation was studied by CSIA and in situ microcosms in combination with TLFA-SIP. • ETBE was degraded when ETBE was the main groundwater contaminant. • ETBE was also degraded in the presence of BTEX and MTBE. • Hydrochemical analysis indicated aerobic and anaerobic ETBE biodegradation. - Abstract: Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental fate has been less investigated, thus far. In the present study, we investigated the in situ biodegradation of ETBE in a fuel-contaminated aquifer using compound-specific stable isotope analysis (CSIA), and in situ microcosms in combination with total lipid fatty acid (TLFA)-stable isotope probing (SIP). In a first field investigation, CSIA revealed insignificant carbon isotope fractionation, but low hydrogen isotope fractionation of up to +14‰ along the prevailing anoxic ETBE plume suggesting biodegradation of ETBE. Ten months later, oxygen injection was conducted to enhance the biodegradation of petroleum hydrocarbons (PH) at the field site. Within the framework of this remediation measure, in situ microcosms loaded with [ 13 C 6 ]-ETBE (BACTRAP ® s) were exposed for 119 days in selected groundwater wells to assess the biodegradation of ETBE by TLFA-SIP under the following conditions: (i) ETBE as main contaminant; (ii) ETBE as main contaminant subjected to oxygen injection; (iii) ETBE plus other PH; (iv) ETBE plus other PH subjected to oxygen injection. Under all conditions investigated, significant 13 C-incorporation into microbial total lipid fatty acids extracted from the in situ microcosms was found, providing clear evidence of ETBE biodegradation
Proceedings of biodegradation

International Nuclear Information System (INIS)

Anon.

1990-01-01

This book contains the proceedings of Biodegradation. Topics include:biodegradation using the tools of biotechnology, basic science aspects of biodegradation, the physiological characteristics of microorganisms, the use of selective techniques that enhance the process of microbial evolution of biodegradative genes in nature, the genetic characteristics of microorganisms allowing them to biodegrade both natural and synthetic toxic chemicals, the molecular techniques that allow selective assembly of genetic segments form a variety of bacterial strains to a single strain, and methods needed to advance biodegradation research as well as the high-priority chemical problems important to the Department of Defense or to the chemical industry
Biodegradation of organ chlorine pesticides in contaminated soil collected from Yen Tap, Cam Khe, Phu Tho

International Nuclear Information System (INIS)

Nguyen Thuy Binh; Nguyen Van Toan; Pham Thi Thai; Dinh Thi Thu Hang

2007-01-01

Biodegradation of POPs contaminant in soil collected from Phu Tho province and Nghe An province had carried out. The process comprises treating soil, which contains anaerobic and aerobic microbes capable of transforming lindane and DDT into harmless material and being under anaerobic and aerobic steps. Significant biodegradation of POPs contaminants occurred in there tests. But some of toxic organic compounds remained. (author)
Preparation and Characteristics of Biodegradable Polyurethane/Clay Nanocomposite Films

Energy Technology Data Exchange (ETDEWEB)

Kim, Seong Woo [Kyonggi University, Suwon (Korea, Republic of)

2013-06-15

Biodegradable polyurethane (PU)/clay nanocomposite films were prepared via extrusion compounding process followed by casting film process. Organically modified montmorillonite (denoted as C30B) with a large amount of hydroxyl groups on its surface was used for the formation of strong bonding with PU resin. From both XRD analysis and TEM observations, the intercalated and exfoliated structure, and dispersion state of silicate platelets in the compounded nanocomposite films were confirmed. In addition, the rheological and tensile properties, optical transparency, oxygen permeability of the prepared nanocomposites were investigated as a function of added nanoclay content, and moreover based on these results, the correlation between the morphology and the resulting properties of the nanocomposites could be presented. The inclusion of nanoclays at appropriate content resulted in remarkable improvement in the nanocomposite performance including tensile modulus, elongation, transparency, and oxygen barrier property, however at excess amount of nanoclays, reduction or very slight increase was observed due to poor dispersion. The biodegradability of the prepared nanocomposite film was evaluated by examining the deterioration in the barrier and tensile properties during degradation period under compost.
Biodegradation of penicillin-G wastewater using Phanerochate ...

African Journals Online (AJOL)

SERVER

2007-06-18

Jun 18, 2007 ... emission of toxic substances and formation of sludge. In recent years, a white rot fungus, ... sporium as a potential microorganism for the biodegrade- tion of polychlorinated ... 1990), paper mill bleach plant effluent (Fukui, 1992) and spentwash (Fahy et al., ..... Studies on biodegradation of toxic compounds.

Complementing approaches to demonstrate chlorinated solvent biodegradation in a complex pollution plume: Mass balance, PCR and compound-specific stable isotope analysis

Science.gov (United States)

Courbet, Christelle; Rivière, Agnès; Jeannottat, Simon; Rinaldi, Sandro; Hunkeler, Daniel; Bendjoudi, Hocine; de Marsily, Ghislain

2011-11-01

This work describes the use of different complementing methods (mass balance, polymerase chain reaction assays and compound-specific stable isotope analysis) to demonstrate the existence and effectiveness of biodegradation of chlorinated solvents in an alluvial aquifer. The solvent-contaminated site is an old chemical factory located in an alluvial plain in France. As most of the chlorinated contaminants currently found in the groundwater at this site were produced by local industries at various times in the past, it is not enough to analyze chlorinated solvent concentrations along a flow path to convincingly demonstrate biodegradation. Moreover, only a few data were initially available to characterize the geochemical conditions at this site, which were apparently complex at the source zone due to (i) the presence of a steady oxygen supply to the groundwater by irrigation canal losses and river infiltration and (ii) an alkaline pH higher than 10 due to former underground lime disposal. A demonstration of the existence of biodegradation processes was however required by the regulatory authority within a timeframe that did not allow a full geochemical characterization of such a complex site. Thus a combination of different fast methods was used to obtain a proof of the biodegradation occurrence. First, a mass balance analysis was performed which revealed the existence of a strong natural attenuation process (biodegradation, volatilization or dilution), despite the huge uncertainty on these calculations. Second, a good agreement was found between carbon isotopic measurements and PCR assays (based on 16S RNA gene sequences and functional genes), which clearly indicated reductive dechlorination of different hydrocarbons (Tetrachloroethene—PCE-, Trichloroethene—TCE-, 1,2- cisDichloroethene— cis-1,2-DCE-, 1,2- transDichloroethene— trans-1,2-DCE-, 1,1-Dichloroethene—1,1-DCE-, and Vinyl Chloride—VC) to ethene. According to these carbon isotope measurements
Biodegradability of Plastics

Directory of Open Access Journals (Sweden)

Yutaka Tokiwa

2009-08-01

Full Text Available Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.. In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.
Cementation of biodegraded radioactive oils and organic waste

International Nuclear Information System (INIS)

Gorbunova, O.; Safonov, A.; Tregubova, V.; German, K.

2015-01-01

The possibility of the microbiological pre-treatment of the oil-containing organic liquid radioactive waste (LRW) before solidification in the cement matrix has been studied. It is experimentally proved that the oil containing cement compounds during long-term storage are subject to microbiological degradation due to the reaction of biogenic organic acids with the minerals of the cement matrix. We recommend to biodegrade the LRW components before their solidification, which reduces the volume of LRW and prevent the destruction of the inorganic cement matrix during the long term storage. The biodegradation of the oil containing LRW is possible by using the radioresistant microflora which oxidize the organic components of the oil to carbon dioxide and water. Simultaneously there is the bio-sorption of the radionuclides by bacteria and emulsification of oil in cement slurry due to biogenic surface-active substances of glycolipid nature. It was experimentally established that after 7 days of biodegradation of oil-containing liquid radioactive waste the volume of LRW is reduced by the factor from 2 to 10 due to the biodegradation of the organic phase to the non-radioactive gases (CH 4 , H 2 O, CO 2 , N 2 ), which are excluded from the volume of the liquid radioactive waste. At the same time, the microorganisms are able to extract from the LRW up to 80-90% of alpha-radionuclides, up to 50% of 90 Sr, up to 20% of 137 Cs due to sorption processes at the cellular structures. The radioactive biomass is subject to dehydration and solidification in the matrix. The report presents the following experimental data: type of bacterial flora, the parameters of biodegradation, the cementing parameters, the properties of the final cement compound with oil-containing liquid radioactive waste
Bioenergetic Strategy for the Biodegradation of p-Cresol by the Unicellular Green Alga Scenedesmus obliquus

Science.gov (United States)

Papazi, Aikaterini; Assimakopoulos, Konstantinos; Kotzabasis, Kiriakos

2012-01-01

Cultures from the unicellular green alga Scenedesmus obliquus biodegrade the toxic p-cresol (4-methylphenol) and use it as alternative carbon/energy source. The biodegradation procedure of p-cresol seems to be a two-step process. HPLC analyses indicate that the split of the methyl group (first step) that is possibly converted to methanol (increased methanol concentration in the growth medium), leading, according to our previous work, to changes in the molecular structure and function of the photosynthetic apparatus and therefore to microalgal biomass increase. The second step is the fission of the intermediately produced phenol. A higher p-cresol concentration results in a higher p-cresol biodegradation rate and a lower total p-cresol biodegradability. The first biodegradation step seems to be the most decisive for the effectiveness of the process, because methanol offers energy for the further biodegradation reactions. The absence of LHCII from the Scenedesmus mutant wt-lhc stopped the methanol effect and significantly reduced the p-cresol biodegradation (only 9%). The present contribution deals with an energy distribution between microalgal growth and p-cresol biodegradation, activated by p-cresol concentration. The simultaneous biomass increase with the detoxification of a toxic phenolic compound (p-cresol) could be a significant biotechnological aspect for further applications. PMID:23251641
Critical evaluation of biodegradable polymers used in nanodrugs

Science.gov (United States)

Marin, Edgar; Briceño, Maria Isabel; Caballero-George, Catherina

2013-01-01

Use of biodegradable polymers for biomedical applications has increased in recent decades due to their biocompatibility, biodegradability, flexibility, and minimal side effects. Applications of these materials include creation of skin, blood vessels, cartilage scaffolds, and nanosystems for drug delivery. These biodegradable polymeric nanoparticles enhance properties such as bioavailability and stability, and provide controlled release of bioactive compounds. This review evaluates the classification, synthesis, degradation mechanisms, and biological applications of the biodegradable polymers currently being studied as drug delivery carriers. In addition, the use of nanosystems to solve current drug delivery problems are reviewed. PMID:23990720
Biodegradation of hydrocarbon compounds in Agbabu natural bitumen

African Journals Online (AJOL)

Infrared spectral changes and gravimetric analysis from the preliminary biodegradability study carried out on Agbabu Natural Bitumen showed the vulnerability of the bitumen to some bacteria: Pseudomonas putrefaciens, Pseudomonas nigrificans, Bacillus licheniformis, Pseudomonas fragi and Achromobacter aerogenes.
Biodegradable films of starch/PVOH/alginate in packaging systems for minimally processed lettuce (Lactuca sativa L.

Directory of Open Access Journals (Sweden)

Renata Paula Herrera Brandelero

Full Text Available ABSTRACT Biodegradable packaging may replace non-biodegradable materials when the shelf life of the packaged product is relatively short, as in minimally processed foods. The objective of this work was to evaluate the efficiency of biodegradable films comprising starch/polyvinyl alcohol (PVOH/alginate with the addition of 0 or 0.5% of essential oil of copaiba (EOCP or lemongrass (EOLM compared to poly-vinyl chloride (PVC films in the storage of minimally processed lettuce. Lettuce samples cut into 1-cm strips were placed in polypropylene trays wrapped with biodegradable films and stored at 6 ± 2 °C for 8 days. PVC films were used as controls. The biofilms presented 11.43-8.11 MPa resistance and 11.3-13.22% elongation, with water vapor permeability (WVP of 0.5-4.04 x 10-12 g. s-1.Pa-1.m-1; thus, the films' properties were considered suitable for the application. The lettuce stored in PVC presented minor total soluble solids (TSS, less luminosity (L, higher intensity of yellow color (b, and eight times less mass loss than that stored in biodegradable films. Multivariate analysis showed that the lettuce lost quality after 2 days of storage in PVC films, representing a different result from the other treatments. Lettuce stored in biodegradable films for 2 and 4 days showed a greater similarity with newly harvested lettuce (time zero. The films with or without the addition of essential oil showed similar characteristics. Biodegradable films were considered viable for the storage of minimally processed lettuce.
Comparison of the efficacy of biodegradable and non-biodegradable scintillation liquids on the counting of tritium- and [14C]-labeled compounds

Directory of Open Access Journals (Sweden)

Medeiros R.B.

2003-01-01

Full Text Available The widespread use of ³H and 14C in research has generated a large volume of waste mixed with scintillation liquid, requiring an effective control and appropriate storage of liquid radioactive waste. In the present study, we compared the efficacy of three commercially available scintillation liquids, Optiphase HiSafe 3, Ultima-Gold(TM AB (biodegradable and Insta-Gel-XF (non-biodegradable, in terms of [14C]-glucose and [³H]-thymidine counting efficiency. We also analyzed the effect of the relative amount of water (1.6 to 50%, radioisotope concentration (0.1 to 100 nCi/ml, pH (2 to 10 and color of the solutions (samples containing 0.1 to 1.0 mg/ml of Trypan blue on the counting efficiency in the presence of these scintillation liquids. There were few significant differences in the efficiency of 14C and ³H counting obtained with biodegradable or non-biodegradable scintillation liquids. However, there was an 83 and 94% reduction in the efficiency of 14C and ³H counting, respectively, in samples colored with 1 mg/ml Trypan blue, but not with 0.1 mg/ml, independent of the scintillation liquid used. Considering the low cost of biodegradable scintillation cocktails and their efficacy, these results show that traditional hazardous scintillation fluids may be replaced with the new safe biodegradable fluids without impairment of ³H and 14C counting efficiency. The use of biodegradable scintillation cocktails minimizes both human and environmental exposure to hazardous solvents. In addition, some biodegradable scintillation liquids can be 40% less expensive than the traditional hazardous cocktails.
Biodegradability of pharmaceutical compounds in agricultural soils irrigated with treated wastewater

International Nuclear Information System (INIS)

Grossberger, Amnon; Hadar, Yitzhak; Borch, Thomas; Chefetz, Benny

2014-01-01

Pharmaceutical compounds (PCs) are introduced into agricultural soils via irrigation with treated wastewater (TWW). Our data show that carbamazepine, lamotrigine, caffeine, metoprolol, sulfamethoxazole and sildenafil are persistent in soils when introduced via TWW. However, other PCs, namely diclofenac, ibuprofen, bezafibrate, gemfibrozil and naproxen were not detected in soils when introduced via TWW. This is likely due to rapid degradation as confirmed in our microcosm studies where they exhibited half-lives (t 1/2 ) between 0.2–9.5 days when soils were spiked at 50 ng/g soil and between 3 and 68 days when soils were spiked at 5000 ng/g soil. The degradation rate and extent of PCs observed in microcosm studies were similar in soils that had been previously irrigated with TWW or fresh water. This suggests that pre-exposure of the soils to PCs via irrigation with TWW does not enhance their biodegradation. This suggests that PCs are probably degraded in soils via co-metabolism. Highlights: • Some pharmaceuticals are highly persistent in arable soils. • Weak acid pharmaceuticals are readily degradable in agricultural soils. • Irrigation with treated wastewater does not enhance degradation of pharmaceuticals. • Degradation of pharmaceuticals in soil is probably occurred via co-metabolism. -- Some pharmaceutical compounds are persistent in arable soils when introduced via irrigation with treated wastewater
Biodegradation of Mexel 432 By Bacteria From the Seine River

International Nuclear Information System (INIS)

Allonier, A.S.; Khalanski, M.

1996-01-01

This report deals with a study of the biodegradation of a filmogenic organic product (Mexel 432) usable in the fight against corrosion, scale and fouling, presenting a certain interest in the research of processes enabling a functional and environmental efficiency for the cooling systems of thermal power stations. The study of the degradation of this product is followed by a global colorimetric method. It shows that the product is stable on the long-term in demineralized water. On the other hand, its rate of disappearance in river waters is significant (50 % in 2 or 3 days). In this phenomenon of disappearance, biodegradation seems to play a part. Some bacteria from the natural environment (river Seine) have been isolated. Two of them seem to play a significant part, since they can degrade the product in three weeks. During the degradation, the amines with long chains (more than six carbons) of the Mexel, measured by the colorimetric method, disappear. The other compounds generated by the biodegradation process are not identified. (authors)
Natural attenuation of petroleum hydrocarbons-a study of biodegradation effects in groundwater (Vitanovac, Serbia).

Science.gov (United States)

Marić, Nenad; Matić, Ivan; Papić, Petar; Beškoski, Vladimir P; Ilić, Mila; Gojgić-Cvijović, Gordana; Miletić, Srđan; Nikić, Zoran; Vrvić, Miroslav M

2018-01-20

The role of natural attenuation processes in groundwater contamination by petroleum hydrocarbons is of intense scientific and practical interest. This study provides insight into the biodegradation effects in groundwater at a site contaminated by kerosene (jet fuel) in 1993 (Vitanovac, Serbia). Total petroleum hydrocarbons (TPH), hydrochemical indicators (O 2 , NO 3 - , Mn, Fe, SO 4 2- , HCO 3 - ), δ 13 C of dissolved inorganic carbon (DIC), and other parameters were measured to demonstrate biodegradation effects in groundwater at the contaminated site. Due to different biodegradation mechanisms, the zone of the lowest concentrations of electron acceptors and the zone of the highest concentrations of metabolic products of biodegradation overlap. Based on the analysis of redox-sensitive compounds in groundwater samples, redox processes ranged from strictly anoxic (methanogenesis) to oxic (oxygen reduction) within a short distance. The dependence of groundwater redox conditions on the distance from the source of contamination was observed. δ 13 C values of DIC ranged from - 15.83 to - 2.75‰, and the most positive values correspond to the zone under anaerobic and methanogenic conditions. Overall, results obtained provide clear evidence on the effects of natural attenuation processes-the activity of biodegradation mechanisms in field conditions.
Combined biodegradation and ozonation for removal of tannins and dyes for the reduction of pollution loads.

Science.gov (United States)

Kanagaraj, James; Mandal, Asit Baran

2012-01-01

Tannins and dyes pose major threat to the environment by generating huge pollution problem. Biodegradation of wattle extract, chrome tannin and dye compounds using suitable fungal culture namely Aspergillus niger, Penicillium sp. were carried out. In addition to these, ozone treatment was carried out to get higher degradation rate. The results were monitored by carrying out chemical oxygen demand (COD), total organic carbon (TOC), and UV-Vis analysis. The results showed that wattle extract (vegetable tannin) gave better biodegradation rate than dye and chromium compounds. Biodegradation plus ozone showed degradation rates of 92-95%, 94-95%, and 85-87% for the wattle extract, dyes, chromium compounds, respectively. UV-Vis showed that there were no peaks observed for biodegraded samples indicating better degradation rates as compared to the control samples. FT-IR spectra analysis suggested that the formation of flavanoid derivatives, chromic oxide and NH(2) compounds during degradation of wattle extract, chromium and dye compounds, respectively, at the peaks of 1,601-1,629 cm(-1), 1,647 cm(-1), and 1,610-1,680 cm(-1). The present investigation shows that combination of biodegradation with ozone is the effective method for the removal of dyes and tannins. The biodegradation of the said compounds in combination with ozonation showed better rate of degradation than by chemical methods. The combination of biodegradation with ozone helps to reduce pollution problems in terms of COD, TOC, total dissolved solids and total suspended solids.
Evaluation of oil biodegradation using time warping and PCA

Energy Technology Data Exchange (ETDEWEB)

Christensen, J.H. [Royal Veterinary and Agricultural Univ., Thorvaldsensvej (Denmark). Dept. of Natural Sciences; Hansen, A.B. [National Environmental Research Inst., Roskilde (Denmark). Dept. of Environmental Chemistry and Microbiology; Andersen, O. [Roskilde Univ., Roskilde (Denmark). Dept. of Life Sciences and Chemistry

2005-07-01

The effects of biodegradation on the composition of stranded oil after the Baltic Carrier oil spill in March 2001 was evaluated using a newly developed multivariate statistical methodology. Gas chromatography and mass spectrometry provided data on the oil compounds and oil biodegradation was determined by applying weighted least square principal component analysis to the preprocessed chromatograms of methylphenanthrenes and methyldibenzothiophenes. One principal component explained 46 per cent of the variation in the complete data set. Samples collected immediately after the spill and 2.5 months after the spill did not exhibit changes in isomer composition. However, the isomer patterns changed in samples collected between 6.5 and 16.5 months after the spill. Samples collected after 8.5 months were the most greatly affected. An evaluation of the degradation patterns suggest that time warping and multivariate statistical methods can successfully identify links between spill samples and can determine how chemical composition will respond to biodegradation processes. 27 refs., 1 tab., 3 figs.
Evaluation of oil biodegradation using time warping and PCA

International Nuclear Information System (INIS)

Christensen, J.H.; Hansen, A.B.; Andersen, O.

2005-01-01

The effects of biodegradation on the composition of stranded oil after the Baltic Carrier oil spill in March 2001 was evaluated using a newly developed multivariate statistical methodology. Gas chromatography and mass spectrometry provided data on the oil compounds and oil biodegradation was determined by applying weighted least square principal component analysis to the preprocessed chromatograms of methylphenanthrenes and methyldibenzothiophenes. One principal component explained 46 per cent of the variation in the complete data set. Samples collected immediately after the spill and 2.5 months after the spill did not exhibit changes in isomer composition. However, the isomer patterns changed in samples collected between 6.5 and 16.5 months after the spill. Samples collected after 8.5 months were the most greatly affected. An evaluation of the degradation patterns suggest that time warping and multivariate statistical methods can successfully identify links between spill samples and can determine how chemical composition will respond to biodegradation processes. 27 refs., 1 tab., 3 figs
Processing and properties of PCL/cotton linter compounds

Energy Technology Data Exchange (ETDEWEB)

Bezerra, Elieber Barros; Franca, Danyelle Campos; Morais, Dayanne Diniz de Souza; Araujo, Edcleide Maria [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais; Rosa, Morsyleide de Freitas; Morais, Joao Paulo Saraiva [Embrapa Tropical Agroindustia, Fortaleza, CE (Brazil); Wellen, Renate Maria Ramos, E-mail: wellen.renate@gmail.com [Universidade Federal da Paraiaba (UFPB), Joao Pessoa, PB (Brazil)

2017-03-15

Biodegradable compounds of poly(ε-caprolactone) (PCL)/ cotton linter were melting mixed with filling content ranging from 1% to 5% w/w. Cotton linter is an important byproduct of textile industry; in this work it was used in raw state and after acid hydrolysis. According to the results of torque rheometry no decaying of viscosity took place during compounding, evidencing absence of breaking down in molecular weight. The thermal stability increased by 20% as observed in HDT for PCL/cotton nanolinter compounds. Adding cotton linter to PCL did not change its crystalline character as showed by XRD; however an increase in degree of crystallinity was observed by means of DSC. From mechanical tests in tension was observed an increase in ductility of PCL, and from mechanical tests in flexion an increase in elastic modulus upon addition of cotton linter, whereas impact strength presented lower values for PCL/cotton linter and PCL/cotton nanolinter compounds. SEM images showed that PCL presents plastic fracture and cotton linter has an interlacing fibril structure with high L/D ratio, which are in agreement with matrix/fibril morphology observed for PCL/cotton linter compounds. PCL/cotton linter compounds made in this work cost less than neat PCL matrix and presented improved properties making feasible its commercial use. (author)
Environmental recovery by destruction of toxic organic compounds using electron beam accelerator

International Nuclear Information System (INIS)

Duarte, C.L; Sampa, M.H.O.; Rela, P.R.; Oikawa, H.

2001-01-01

The oxidation process has attracted many researchers because of the capacity to mineralise organic compounds. The most efficient oxidation is the use of OH radicals. There are various methods to generate OH radicals as the use of ozone, hydrogen peroxide and ultra-violet (AOP - Advanced Oxidation Process). The most simple and efficient method for generating OH radicals in situ is the interaction of ionizing radiation with water. The reactive species formed by the water irradiation are the reducing radical's solvated electron and H atoms and the oxidising radical hydroxyl OH. The reactive species will react with organic compounds in the water inducing their decomposition. The use of ionizing radiation has great ecological and technologies advantages, especially when compared to physical-chemical and biological methods. It degrades organic compounds, generating substances that are easily biodegraded without the necessity of adding chemical compounds. The purpose of the radiation treatment is the conversion of these substances to biodegradable compounds; sometimes the complete decomposition is not necessary for this conversion
Biodegradation of bituminous products from processing liquid radioactive wastes

International Nuclear Information System (INIS)

Tibensky, L.; Krejci, F.; Hladky, E.; Halama, D.

1988-01-01

One of the possible ways of disturbing the stability of bituminous products from liquid radioactive waste processing, is biodegradation caused by common microorganisms. Pseudomonas bacteria and a Bacillus cereus culture were selected for experimental study of cultivation of microorganisms. Experiments with mixed cultures were also performed. Pitches, ajatin and imidazoline were used as inhibitors. The thin layer and the emulsion methods were used in assessing biological corrosion. The results of the experiments are discussed with respect to the dependence of bacterial growth on bitumen biodegradation, the effect of pH on bitumen degradation and the effect of inhibitors on bitumen biodegradation. The salts contained in bituminous products were not found to significantly affect the rate of destruction. The degree of degradation was found to mainly depend on the bitumen, its chemical composition, and on the conditions of storage. It was also found that inhibitor additions in some cases modified the properties of the matrix such that it became more liquid. The coefficient of extractibility thus increased of matrix salts. The recultivation of bacteria on a full-value medium resulted in the loss of the inhibitory effect. In some cases, the inhibitor even stimulated the growth of microorganisms. The use of inhibitors in an effort to achieve biostability of bituminous products thus did not solve the problem. (Z.M.). 2 tabs., 9 refs
In-situ treatment of PCP contaminated soil by electrokinetics-Fenton-biodegradation process

Energy Technology Data Exchange (ETDEWEB)

Yang, G.C.C.; Chen Jenteh [Inst. of Environmental Engineering, National Sun Yat-Sen Univ., Kaohsiung (Taiwan)

2001-07-01

This laboratory investigation was conducted to evaluate the treatment efficiency of a process combining electrokinetic remediation (EK), Fenton process, and biodegradation for treating a pentachlorophenol (PCP) contaminated soil. For EK-Fenton experiments, the results have indicated that an increase of treatment time (e.g., from 10 to 15 days) would substantially increase the overall treatment (i.e., removal and destruction) efficiency of PCP. Only a limited increase of the treatment efficiency would be found if the concentration of FeSO{sub 4} was increased from 0.0196M to 0.098M. When scrap iron power was employed as the catalyst, the residual PCP concentration for soil near the anode end was found to be lower than that of 0.0196M FeSO{sub 4}. But its overall treatment efficiency was only 56.58%, which is lower than 68.34% obtained by using 0.0196M FeSO{sub 4} and 0.35% H{sub 2}O{sub 2}. When H{sub 2}O{sub 2} concentration was further increased to 3.5%, an overall treatment efficiency of 79.77% would be obtained when 0.0196M FeSO{sub 4} was used. When treated by EK-biodegradation process with phenol enrichment bacteria, the overall treatment efficiency of PCP was as low as 25.67%. If PCP contaminated soil was pre-treated by EK-Fenton process and followed by EK-biodegradation, an overall treatment efficiency of 100% was found to be achievable. (orig.)
Synthesis of biodegradable plastic from tapioca with N-Isopropylacrylamid and chitosan using glycerol as plasticizer

Science.gov (United States)

Syaubari; Safwani, S.; Riza, M.

2018-04-01

One of natural polymers that can be used as raw material in the manufacture of biodegradable plastic is tapioca and chitosan. The addition of other compounds such as glycerol as plasticizer is to improve the characteristics of the plastic that already produced. N- Isopropylacrylamid (NIPAm) is an organic compound that can be synthesized into a polymer or polymer grafting which also biodegradable too. This research aims tostudy the synthesis of biodegradable plastics from tapioca with the addition of chitosan, NIPAm, poly(NIPAm) and analyze the characteristics of biodegradable plastics that already produced. This research was done in three stages, there are (1) polymerization NIPAm, (2) the grafting of chitosan-poly NIPAm and (3) the synthesis of biodegradable plastics from starch mixture with variation of addition chitosan, NIPAm, poly(NIPAm), chitosan-graft-poly(NIPAm) and also variations of glycerol as plasticizer. The results of this research is a thin sheet of plastic which is will get analyzed for the characteristics of functional groups, mechanical, morphological and its biodegradability. FTIR spectra showed the grafting process with the new group formation of CO single-bond at 850 cm-1. Plastic with the addition of NIPAm and 1 ml glycerol has the highest tensile strength value about 31.1 MPa. Plastic with poly(NIPAm) and 4 ml glycerol produces the highest elongation value about 153.72%. Plastic with Chitosan-graft-poly(NIPAm) with 1 ml glycerol has the longest biodegradation because of the small mass-loss for six weeks which is about 6.6%.
Impact of heavy metals on the oil products biodegradation process.

Science.gov (United States)

Zukauskaite, Audrone; Jakubauskaite, Viktorija; Belous, Olga; Ambrazaitiene, Dalia; Stasiskiene, Zaneta

2008-12-01

Oil products continue to be used as a principal source of energy. Wide-scale production, transport, global use and disposal of petroleum have made them major contaminants in prevalence and quantity in the environment. In accidental spills, actions are taken to remove or remediate or recover the contaminants immediately, especially if they occur in environmentally sensitive areas, for example, in coastal zones. Traditional methods to cope with oil spills are confined to physical containment. Biological methods can have an advantage over the physical-chemical treatment regimes in removing spills in situ as they offer biodegradation of oil fractions by the micro-organisms. Recently, biological methods have been known to play a significant role in bioremediation of oil-polluted coastal areas. Such systems are likely to be of significance in the effective management of sensitive coastal ecosystems chronically subjected to oil spillage. For this reason the aim of this paper is to present an impact of Mn, Cu, Co and Mo quantities on oil biodegradation effectiveness in coastal soil and to determine the relationship between metal concentrations and degradation of two oil products (black oil and diesel fuel). Soil was collected in the Baltic Sea coastal zone oil products degradation area (Klaipeda, Lithuania). The experiment consisted of two parts: study on the influence of micro-elements on the oil product biodegradation process; and analysis of the influence of metal concentration on the number of HDMs. The analysis performed and results obtained address the following areas: impact of metal on a population of hydrocarbon degrading micro-organisms, impact of metals on residual concentrations of oil products, influence of metals on the growth of micro-organisms, inter-relation of metal concentrations with degradation rates. Statistical analysis was made using ;Statgraphics plus' software. The influence of metals on the growth of micro-organisms, the biodegradation process

Fate of sulfonamide antibiotics in contact with activated sludge--sorption and biodegradation.

Science.gov (United States)

Yang, Sheng-Fu; Lin, Cheng-Fang; Wu, Chien-Ju; Ng, Kok-Kwang; Lin, Angela Yu-Chen; Hong, Pui-Kwan Andy

2012-03-15

The sorption and biodegradation of three sulfonamide antibiotics, namely sulfamethoxazole (SMX), sulfadimethoxine (SDM), and sulfamonomethoxine (SMM), in an activated sludge system were investigated. Experiments were carried out by contacting 100 μg/L of each sulfonamide compound individually with 2.56 g/L of MLSS at 25±0.5 °C, pH 7.0, and dissolved oxygen of 3.0±0.1 mg/L in a batch reactor over different periods of 2 d and 14 d. All sulfonamides were removed completely over 11-13 d. Sorptive equilibrium was established well within the first few hours, followed by a lag period of 1-3 days before biodegradation was to deplete the antibiotic compounds linearly in the ensuing 10 days. Apparent zeroth-order rate constants were obtained by regression analysis of measured aqueous concentration vs. time profiles to a kinetic model accounting for sorption and biodegradation; they were 8.1, 7.9, and 7.7 μg/L/d for SDM, SMX, and SMM, respectively, at activated sludge concentration of 2.56 g/L. The measured kinetics implied that with typical hydraulic retention time (e.g. 6 h) provided by WWTP the removal of sulfonamide compounds from the wastewater during the activated sludge process would approximate 2 μg/L. Copyright © 2011 Elsevier Ltd. All rights reserved.
Azoarcus sp. CIB, an anaerobic biodegrader of aromatic compounds shows an endophytic lifestyle.

Directory of Open Access Journals (Sweden)

Helga Fernández

Full Text Available BACKGROUND: Endophytic bacteria that have plant growth promoting traits are of great interest in green biotechnology. The previous thought that the Azoarcus genus comprises bacteria that fit into one of two major eco-physiological groups, either free-living anaerobic biodegraders of aromatic compounds or obligate endophytes unable to degrade aromatics under anaerobic conditions, is revisited here. METHODOLOGY/PRINCIPAL FINDINGS: Light, confocal and electron microscopy reveal that Azoarcus sp. CIB, a facultative anaerobe β-proteobacterium able to degrade aromatic hydrocarbons under anoxic conditions, is also able to colonize the intercellular spaces of the rice roots. In addition, the strain CIB displays plant growth promoting traits such nitrogen fixation, uptake of insoluble phosphorus and production of indoleacetic acid. Therefore, this work demonstrates by the first time that a free-living bacterium able to degrade aromatic compounds under aerobic and anoxic conditions can share also an endophytic lifestyle. The phylogenetic analyses based on the 16S rDNA and nifH genes confirmed that obligate endophytes of the Azoarcus genus and facultative endophytes, such as Azoarcus sp. CIB, locate into different evolutionary branches. CONCLUSIONS/SIGNIFICANCE: This is the first report of a bacterium, Azoarcus sp. CIB, able to degrade anaerobically a significant number of aromatic compounds, some of them of great environmental concern, and to colonize the rice as a facultative endophyte. Thus, Azoarcus sp. CIB becomes a suitable candidate for a more sustainable agricultural practice and phytoremediation technology.
Biodegradability of poly(butylene succinate-co-butylene adipate) (PBSA) controlled by temperature during the dried-gel process

Science.gov (United States)

Yamazaki, Hana; Maeda, Tomoki; Hotta, Atsushi

Currently there is a growing interest in biodegradable plastics that can be readily degraded into H2O and CO2. Among them, poly(butylene succinate-co-butylene adipate)(PBSA) is one of the mechanically attractive materials that can be biodegraded by surrounding water molecules and microorganisms after the disposal of the plastics. In order to expand the use of PBSA, the proper and effective control of the biodegradability of PBSA should be realized. In this work, the dried-gel process of the PBSA was carefully studied considering the temperature of the process. Three different types of dried PBSA gels were prepared at three different gel-process temperatures. From the biodegradability testing by immersing the PBSA samples in NaOH aq., it was found that the percentage of the weight loss of the PBSA was increased, indicating that the biodegradability was enhanced as the gel preparation temperature became lower. In fact, smaller spherocrystals were observed in PBSA dried at cooler temperature, studied by the scanning electron microscopy (SEM). It was therefore concluded that the microstructures of PBSA could be well controlled by changing the gel preparation temperatures for the precise control of the biodegradability of PBSA. This work was supported by a Grant-in-Aid for Scientific Research (A) (No. 15H02298 to A.H.) and a Grant-in-Aid for Research Activity Start-up (No.15H06586 to T.M.) from JSPS: KAKENHI\\x9D.
Role of Dehalogenases in Aerobic Bacterial Degradation of Chlorinated Aromatic Compounds

Directory of Open Access Journals (Sweden)

Pankaj Kumar Arora

2014-01-01

Full Text Available This review was conducted to provide an overview of dehalogenases involved in aerobic biodegradation of chlorinated aromatic compounds. Additionally, biochemical and molecular characterization of hydrolytic, reductive, and oxygenolytic dehalogenases was reviewed. This review will increase our understanding of the process of dehalogenation of chlorinated aromatic compounds.
Biodegradation of organic compounds in vadose zone and aquifer sediments

International Nuclear Information System (INIS)

Konopka, A.; Turco, R.

1991-01-01

The microbial processes that occur in the subsurface under a typical Midwest agricultural soil were studied. A 26-m bore was installed in November of 1988 at a site of the Purdue University Agronomy Research Center. Aseptic collections of soil materials were made at 17 different depths. Physical analysis indicated that the site contained up to 14 different strata. The site materials were primarily glacial tills with a high carbonate content. The N,P, and organic C contents of sediments tended to decrease with depth. Ambient water content was generally less than the water content, which corresponds to a -0.3-bar equivalent. No pesticides were detected in slurry incubations of up to 128 days. The sorption of atrazine and metolachlor was correlated with the clay content of the sediments. Microbial biomass (determined by direct microscopic count, viable count, and phospholipid assay) in the tills was lower than in either the surface materials or the aquifer located at 25 m. The biodegradation of glucose and phenol occurred rapidly and without a lag in samples from the aquifer capillary fringe, saturated zone, and surface soils. In contrast, lag periods and smaller biodegradation rates were found in the till samples. Subsurface sediments are rich in microbial numbers and activity. The most active strata appear to be transmissive layers in the saturated zone. This implies that the availability of water may limit activity in the profile
Enhancement of olive mill wastewater biodegradation by homogeneous and heterogeneous photocatalytic oxidation

Energy Technology Data Exchange (ETDEWEB)

Badawy, M.I.; Gohary, F.El. [Water Pollution Research Department, National Research Centre (NRC), Dokki, Cairo 11312 (Egypt); Ghaly, M.Y., E-mail: ghalynrc@yahoo.com [Chemical Engineering and Pilot Plant Department, National Research Centre (NRC), Dokki, Cairo (Egypt); Ali, M.E.M. [Water Pollution Research Department, National Research Centre (NRC), Dokki, Cairo 11312 (Egypt)

2009-09-30

Olive mills wastewater (OMW) is characterized by its high organic content and refractory compounds. In this study, an advanced technology for the treatment of the recalcitrant contaminants of OMW has been investigated. The technique used was either photo-Fenton as homogeneous photocatalytic oxidation or UV/semi-conductor catalyst (such as TiO{sub 2}, ZrO{sub 2} and FAZA) as heterogeneous photocatalytic oxidation for treatment of OMW. For both the processes, the effect of irradiation time, amounts of photocatalysts and semi-conductors, and initial concentration of hydrogen peroxide has been studied. At the optimum conditions, photo-Fenton process achieved COD, TOC, lignin (total phenolic compounds) and total suspended solids (TSSs) removal values of 87%, 84%, 97.44% and 98.31%, respectively. The corresponding values for UV/TiO{sub 2} were 68.8%, 67.3%, 40.19% and 48.9%, respectively, after 80 min irradiation time. The biodegradability expressed by BOD{sub 5}/COD ratio for treated wastewater was ranged from 0.66 to 0.8 compared to 0.19 for raw wastewater indicating enhancement of biodegradation.
Biodegradation of ciprofloxacin in water and soil and its effects on the microbial communities

International Nuclear Information System (INIS)

Girardi, Cristobal; Greve, Josephine; Lamshöft, Marc; Fetzer, Ingo; Miltner, Anja; Schäffer, Andreas; Kästner, Matthias

2011-01-01

Highlights: ► Mineralisation of toxic pollutants can be higher in soil than in water. ► Ciprofloxacin affects the microbial communities and activities in soil. ► Toxicity of ciprofloxacin is reduced in soil due to sorption processes. ► Despite the buffering capacity of soil, ciprofloxacin remains active. ► Ciprofloxacin resistance can develop in soils contaminated with this antibiotic. - Abstract: While antibiotics are frequently found in the environment, their biodegradability and ecotoxicological effects are not well understood. Ciprofloxacin inhibits active and growing microorganisms and therefore can represent an important risk for the environment, especially for soil microbial ecology and microbial ecosystem services. We investigated the biodegradation of 14 C-ciprofloxacin in water and soil following OECD tests (301B, 307) to compare its fate in both systems. Ciprofloxacin is recalcitrant to biodegradation and transformation in the aqueous system. However, some mineralisation was observed in soil. The lower bioavailability of ciprofloxacin seems to reduce the compound's toxicity against microorganisms and allows its biodegradation. Moreover, ciprofloxacin strongly inhibits the microbial activities in both systems. Higher inhibition was observed in water than in soil and although its antimicrobial potency is reduced by sorption and aging in soil, ciprofloxacin remains biologically active over time. Therefore sorption does not completely eliminate the effects of this compound.
Comparison of ready biodegradation estimation methods for fragrance materials.

Science.gov (United States)

Boethling, Robert

2014-11-01

Biodegradability is fundamental to the assessment of environmental exposure and risk from organic chemicals. Predictive models can be used to pursue both regulatory and chemical design (green chemistry) objectives, which are most effectively met when models are easy to use and available free of charge. The objective of this work was to evaluate no-cost estimation programs with respect to prediction of ready biodegradability. Fragrance materials, which are structurally diverse and have significant exposure potential, were used for this purpose. Using a database of 222 fragrance compounds with measured ready biodegradability, 10 models were compared on the basis of overall accuracy, sensitivity, specificity, and Matthews correlation coefficient (MCC), a measure of quality for binary classification. The 10 models were VEGA© Non-Interactive Client, START (Toxtree©), Biowin©1-6, and two models based on inductive machine learning. Applicability domain (AD) was also considered. Overall accuracy was ca. 70% and varied little over all models, but sensitivity, specificity and MCC showed wider variation. Based on MCC, the best models for fragrance compounds were Biowin6, VEGA and Biowin3. VEGA performance was slightly better for the 0.8). However, removing compounds with one and only one quaternary carbon yielded similar improvement in predictivity for VEGA, START, and Biowin3/6, with a smaller penalty in reduced coverage. Of the nine compounds for which the eight models (VEGA, START, Biowin1-6) all disagreed with the measured value, measured analog data were available for seven, and all supported the predicted value. VEGA, Biowin3 and Biowin6 are judged suitable for ready biodegradability screening of fragrance compounds. Published by Elsevier B.V.
Linear and nonlinear relationships between biodegradation potential and molecular descriptors/fragments for organic pollutants and a theoretical interpretation

International Nuclear Information System (INIS)

He, Jia; Qin, Weichao; Zhang, Xujia; Wen, Yang; Su, Limin; Zhao, Yuanhui

2013-01-01

Prediction of the biodegradability of organic pollutants is an ecologically desirable and economically feasible tool for estimating the environmental fate of chemicals. In this paper, linear and nonlinear relationships between biological oxygen demand (BOD) and molecular descriptors/fragments have been investigated for 1130 organic chemicals. Significant relationships have been observed between the simple molecular descriptors and %BOD for some homologous compounds, but not for the whole set of compounds. Electronic parameters, such as E HOMO and E LUMO , are the dominant factors affecting the biodegradability for some homologous chemicals. However, other descriptors, such as molecular weight, acid dissociation constant and polarity still have a significant impact on the biodegradation. The best global model for %BOD prediction is that developed from a chain-based fragmentation scheme. At the same time, the theoretical relationship between %BOD and molecular descriptors/fragments has been investigated, based on a first-order kinetic process. The %BOD is nonlinearly, rather than linearly, related to the descriptors. The coefficients of determination can be significantly improved by using nonlinear models for the homologous compounds and the whole data set. After analysing 1130 ready and not ready biodegradable compounds using 23 simple descriptors and various fragmentation schemes, it was revealed that biodegradation could be well predicted from a chain-based fragmentation scheme, a decision tree and a %BOD model. The models were capable of separating NRB and RB with an overall accuracy of 87.2%, 83.0% and 82.5%, respectively. The best classification model developed was a chain-based model but it used 155 fragments. The simplest model was a decision tree which only used 10 structural fragments. The effect of structures on the biodegradation has been analysed and the biodegradation pathway and mechanisms have been discussed based on activating and inactivating
Anoxic denitrification of BTEX: Biodegradation kinetics and pollutant interactions.

Science.gov (United States)

Carvajal, Andrea; Akmirza, Ilker; Navia, Daniel; Pérez, Rebeca; Muñoz, Raúl; Lebrero, Raquel

2018-05-15

Anoxic mineralization of BTEX represents a promising alternative for their abatement from O 2 -deprived emissions. However, the kinetics of anoxic BTEX biodegradation and the interactions underlying the treatment of BTEX mixtures are still unknown. An activated sludge inoculum was used for the anoxic abatement of single, dual and quaternary BTEX mixtures, being acclimated prior performing the biodegradation kinetic tests. The Monod model and a Modified Gompertz model were then used for the estimation of the biodegradation kinetic parameters. Results showed that both toluene and ethylbenzene are readily biodegradable under anoxic conditions, whereas the accumulation of toxic metabolites resulted in partial xylene and benzene degradation when present both as single components or in mixtures. Moreover, the supplementation of an additional pollutant always resulted in an inhibitory competition, with xylene inducing the highest degree of inhibition. The Modified Gompertz model provided an accurate fitting for the experimental data for single and dual substrate experiments, satisfactorily representing the antagonistic pollutant interactions. Finally, microbial analysis suggested that the degradation of the most biodegradable compounds required a lower microbial specialization and diversity, while the presence of the recalcitrant compounds resulted in the selection of a specific group of microorganisms. Copyright © 2018 Elsevier Ltd. All rights reserved.
Blendas PHB/copoliésteres biodegradáveis : biodegradação em solo Biodegradable PHB/copolyester blends : biodegradation in soil

Directory of Open Access Journals (Sweden)

Suzan A. Casarin

2013-01-01

Full Text Available Este trabalho apresenta os resultados do comportamento de blendas do polímero biodegradável PHB poli(hidroxibutirato com os copoliésteres também biodegradáveis EastarBio® e Ecoflex®, na composição de 75% de PHB e 25% dos copoliésteres, em contato com solo composto simulado. Foi também avaliada a influência da adição de pó de serra ou farinha de madeira, na proporção de 70% da blenda e 30% de pó de serra (p.d.s.. A biodegradação foi avaliada para amostras após 30, 60 e 90 dias em contato com solo, através de análises gravimétricas, morfológicas e mecânicas. A preparação inicial dos grânulos dos compostos poliméricos foi feita por extrusão, utilizando uma extrusora dupla-rosca e a moldagem dos corpos de prova foi realizada através da moldagem por injeção. Os materiais estudados biodegradam nas condições testadas. A blenda PHB/EastarBio® (75/25 + 30% p.d.s. apresentou maior redução de massa, 29% após 90 dias. Notou-se que a biodegradação se inicia pela superfície do material e que 90 dias são insuficientes para observar alterações internas.This paper reports on blends made with the biodegradable polymers poly(hydroxybutyrate (PHB and Eastar Bio® or Ecoflex® copolyesters, in contact with simulated compound soil. The blends had 75% of PHB and 25% of copolyesters. We also analyzed the influence from adding 30% of powder-wood or wood flour (WPC to 70% of the blend. Biodegradation was analyzed for samples after 30, 60 and 90 days in contact with soil, through thermogravimetric, morphological and mechanical analyses. The initial preparation of the granules of polymeric compounds was made by extrusion, using a twin-screw extruder and the molding of the specimens was performed by injection molding. The analysis indicated material biodegradation under the conditions tested. The PHB/Eastar Bio® blend (75/25 + 30% WPC exhibited the highest degradation with 29% of mass loss at the end of 90 days. Biodegradation
Biodegradation of bacterial polysaccharides adsorbed on montmorillonite

International Nuclear Information System (INIS)

Guckert, A.; Tok, H.H.; Jacquin, F.

1977-01-01

In this research, by means of a model, a study was made of the biodegradation of microbial organic compounds adsorbed on clays, with a parallel experiment on Fontainebleau sand serving as the control. During incubation the three classes of organic matter ( 14 C-labelled glucose, 14 C-labelled polysaccharides and 14 C-labelled microbial cells) mineralize more actively in the presence of sand than in the presence of clay, since the latter provides protection against biodegradation. Mineralization of the adsorbed organic compounds, however, is marked by clear-cut differences after three weeks - glucose (55%)>polysaccharides (43%)>microbial organisms (7.3%). After incubation, chemical extraction of the organo-mineral complexes by alkaline solvents shows only water-soluble and alkali-soluble products in the case of sand; conversely, in that of montmorillonite the bulk of the 14 C was found in the non-extractable fraction or humin (18.1% of the initial 14 C for glucose, 27.3% for the polysaccharides, and 67.6% for the microbial organisms). A second incubation carried out after a phase in which there was drying and remoistening of the organo-mineral complexes, brings to light the important part played by climatic alternations during the biodegradation process. A new mineralization phase is observed, affecting more the bacterial organisms (14.1%) than the polysaccharides (6.3%), with the glucose-base complexes occupying an intermediate position (11.2%). The chemical fractioning of the organo-mineral complexes following re-incubation shows the stability of 14 C in humin very clearly, especially in the case of polysaccharides, where the mineralization phase relates primarily to the products extractable with alkalis. (author)
Chloroethene Biodegradation Potential, ADOT/PF Peger Road Maintenance Facility, Fairbanks, Alaska

Science.gov (United States)

Bradley, Paul M.; Chapelle, Frances H.

2004-01-01

A series of 14C-radiotracer-based microcosm experiments were conducted to assess: 1) the extent, rate and products of microbial dechlorination of trichloroethene (TCE), cis-dichloroethene (cis-DCE) and vinyl chloride (VC) in sediments at the Peger Road site; 2) the effect of three electron donor amendments (molasses, shrimp and crab chitin, and 'Hydrogen Release Compound' (HRC)) on microbial degradation of TCE in three Peger Road sediments; and 3) the potential significance at the site of chloroethene biodegradation processes other than reductive dechlorination. In these experiments, TCE biodegradation yielded the reduced products, DCE and VC, and the oxidation product CO 2. Biodegradation of DCE and VC involved stoichiometric oxidation to CO 2. Both laboratory microcosm study and field redox assessment results indicated that the predominant terminal electron accepting process in Peger Road plume sediments under anoxic conditions was Mn/Fe-reduction. The rates of chloroethene biodegradation observed in Peger Road sediment microcosms under low temperature conditions (4?C) were within the range of those observed in sediments from temperate (20?C) aquifer systems. This result confirmed that biodegradation can be a significant mechanism for in situ contaminant remediation even in cold temperature aquifers. The fact that CO2 was the sole product of cis-DCE and VC biodegradation detected in Peger Road sediments indicated that a natural attenuation assessment based on reduced daughter product accumulation may significantly underestimate the potential for DCE and VC biodegradation at the Peger Road. Neither HRC nor molasses addition stimulated TCE reductive dechlorination. The fact that molasses and HRC amendment did stimulate Mn/Fe-reduction suggests that addition of these electron donors favored microbial Mn/Fe-reduction to the detriment of microbial TCE dechlorinating activity. In contrast, amendment of sediment microcosms with shrimp and crab chitin resulted in the
Biodegradation of ciprofloxacin in water and soil and its effects on the microbial communities

Energy Technology Data Exchange (ETDEWEB)

Girardi, Cristobal, E-mail: cristobal.girardi-lavin@ufz.de [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstrasse 15, 04318 Leipzig (Germany); Greve, Josephine [Minnesota State University, Mankato, MN 56001 8400 (United States); Lamshoeft, Marc [Institute of Environmental Research (INFU), TU Dortmund University, Otto-Hahn-Str. 6, NRW 44221 Dortmund (Germany); Fetzer, Ingo [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig (Germany); Miltner, Anja [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstrasse 15, 04318 Leipzig (Germany); Schaeffer, Andreas [Department of Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Kaestner, Matthias [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstrasse 15, 04318 Leipzig (Germany)

2011-12-30

Highlights: Black-Right-Pointing-Pointer Mineralisation of toxic pollutants can be higher in soil than in water. Black-Right-Pointing-Pointer Ciprofloxacin affects the microbial communities and activities in soil. Black-Right-Pointing-Pointer Toxicity of ciprofloxacin is reduced in soil due to sorption processes. Black-Right-Pointing-Pointer Despite the buffering capacity of soil, ciprofloxacin remains active. Black-Right-Pointing-Pointer Ciprofloxacin resistance can develop in soils contaminated with this antibiotic. - Abstract: While antibiotics are frequently found in the environment, their biodegradability and ecotoxicological effects are not well understood. Ciprofloxacin inhibits active and growing microorganisms and therefore can represent an important risk for the environment, especially for soil microbial ecology and microbial ecosystem services. We investigated the biodegradation of {sup 14}C-ciprofloxacin in water and soil following OECD tests (301B, 307) to compare its fate in both systems. Ciprofloxacin is recalcitrant to biodegradation and transformation in the aqueous system. However, some mineralisation was observed in soil. The lower bioavailability of ciprofloxacin seems to reduce the compound's toxicity against microorganisms and allows its biodegradation. Moreover, ciprofloxacin strongly inhibits the microbial activities in both systems. Higher inhibition was observed in water than in soil and although its antimicrobial potency is reduced by sorption and aging in soil, ciprofloxacin remains biologically active over time. Therefore sorption does not completely eliminate the effects of this compound.
Rubber compounding and processing

CSIR Research Space (South Africa)

John, MJ

2014-06-01

Full Text Available This chapter presents an overview on the compounding and processing techniques of natural rubber compounds. The introductory portion deals with different types of rubbers and principles of rubber compounding. The primary and secondary fillers used...
Role of biodegradation in the removal of pharmaceutically active compounds with different bulk organic matter characteristics through managed aquifer recharge: Batch and column studies

KAUST Repository

Maeng, Sungkyu; Sharma, Saroj K.; Abel, Chol D T; Magic-Knezev, Aleksandra; Amy, Gary L.

2011-01-01

Natural water treatment systems such as bank filtration have been recognized as providing effective barriers in the multi-barrier approach for attenuation of organic micropollutants for safe drinking water supply. In this study, the role of biodegradation in the removal of selected pharmaceutically active compounds (PhACs) during soil passage was investigated. Batch studies were conducted to investigate the removal of 13 selected PhACs from different water sources with respect to different sources of biodegradable organic matter. Neutral PhACs (phenacetine, paracetamol, and caffeine) and acidic PhACs (ibuprofen, fenoprofen, bezafibrate, and naproxen) were removed with efficiencies greater than 88% from different organic matter water matrices during batch studies (hydraulic retention time (HRT): 60 days). Column experiments were then performed to differentiate between biodegradation and sorption with regard to the removal of selected PhACs. In column studies, removal efficiencies of acidic PhACs (e.g., analgesics) decreased under conditions of limited biodegradable carbon. The removal efficiencies of acidic PhACs were found to be less than 21% under abiotic conditions. These observations were attributed to sorption under abiotic conditions established by a biocide (20 mM sodium azide), which suppresses microbial activity/biodegradation. However, under biotic conditions, the removal efficiencies of these acidic PhACs were found to be greater than 59%. This is mainly attributed to biodegradation. Moreover, the average removal efficiencies of hydrophilic (polar) neutral PhACs (paracetamol, pentoxifylline, and caffeine) with low octanol/water partition coefficients (log K ow less than 1) were low (11%) under abiotic conditions. However, under biotic conditions, removal efficiencies of the neutral PhACs were greater than 98%. In contrast, carbamazepine persisted and was not easily removed under either biotic or abiotic conditions. This study indicates that biodegradation
Role of biodegradation in the removal of pharmaceutically active compounds with different bulk organic matter characteristics through managed aquifer recharge: Batch and column studies

KAUST Repository

Maeng, Sungkyu

2011-10-01

Natural water treatment systems such as bank filtration have been recognized as providing effective barriers in the multi-barrier approach for attenuation of organic micropollutants for safe drinking water supply. In this study, the role of biodegradation in the removal of selected pharmaceutically active compounds (PhACs) during soil passage was investigated. Batch studies were conducted to investigate the removal of 13 selected PhACs from different water sources with respect to different sources of biodegradable organic matter. Neutral PhACs (phenacetine, paracetamol, and caffeine) and acidic PhACs (ibuprofen, fenoprofen, bezafibrate, and naproxen) were removed with efficiencies greater than 88% from different organic matter water matrices during batch studies (hydraulic retention time (HRT): 60 days). Column experiments were then performed to differentiate between biodegradation and sorption with regard to the removal of selected PhACs. In column studies, removal efficiencies of acidic PhACs (e.g., analgesics) decreased under conditions of limited biodegradable carbon. The removal efficiencies of acidic PhACs were found to be less than 21% under abiotic conditions. These observations were attributed to sorption under abiotic conditions established by a biocide (20 mM sodium azide), which suppresses microbial activity/biodegradation. However, under biotic conditions, the removal efficiencies of these acidic PhACs were found to be greater than 59%. This is mainly attributed to biodegradation. Moreover, the average removal efficiencies of hydrophilic (polar) neutral PhACs (paracetamol, pentoxifylline, and caffeine) with low octanol/water partition coefficients (log K ow less than 1) were low (11%) under abiotic conditions. However, under biotic conditions, removal efficiencies of the neutral PhACs were greater than 98%. In contrast, carbamazepine persisted and was not easily removed under either biotic or abiotic conditions. This study indicates that biodegradation
Role of biodegradation in the removal of pharmaceutically active compounds with different bulk organic matter characteristics through managed aquifer recharge: batch and column studies.

Science.gov (United States)

Maeng, Sung Kyu; Sharma, Saroj K; Abel, Chol D T; Magic-Knezev, Aleksandra; Amy, Gary L

2011-10-15

Natural water treatment systems such as bank filtration have been recognized as providing effective barriers in the multi-barrier approach for attenuation of organic micropollutants for safe drinking water supply. In this study, the role of biodegradation in the removal of selected pharmaceutically active compounds (PhACs) during soil passage was investigated. Batch studies were conducted to investigate the removal of 13 selected PhACs from different water sources with respect to different sources of biodegradable organic matter. Neutral PhACs (phenacetine, paracetamol, and caffeine) and acidic PhACs (ibuprofen, fenoprofen, bezafibrate, and naproxen) were removed with efficiencies greater than 88% from different organic matter water matrices during batch studies (hydraulic retention time (HRT): 60 days). Column experiments were then performed to differentiate between biodegradation and sorption with regard to the removal of selected PhACs. In column studies, removal efficiencies of acidic PhACs (e.g., analgesics) decreased under conditions of limited biodegradable carbon. The removal efficiencies of acidic PhACs were found to be less than 21% under abiotic conditions. These observations were attributed to sorption under abiotic conditions established by a biocide (20 mM sodium azide), which suppresses microbial activity/biodegradation. However, under biotic conditions, the removal efficiencies of these acidic PhACs were found to be greater than 59%. This is mainly attributed to biodegradation. Moreover, the average removal efficiencies of hydrophilic (polar) neutral PhACs (paracetamol, pentoxifylline, and caffeine) with low octanol/water partition coefficients (log Kow less than 1) were low (11%) under abiotic conditions. However, under biotic conditions, removal efficiencies of the neutral PhACs were greater than 98%. In contrast, carbamazepine persisted and was not easily removed under either biotic or abiotic conditions. This study indicates that biodegradation
Non-biodegradable landfill leachate treatment by combined process of agitation, coagulation, SBR and filtration

Energy Technology Data Exchange (ETDEWEB)

Abood, Alkhafaji R. [State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074 (China); Thi Qar University, Nasiriyah (Iraq); Bao, Jianguo, E-mail: bjianguo888@126.com [State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074 (China); Du, Jiangkun; Zheng, Dan; Luo, Ye [State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074 (China)

2014-02-15

Highlights: • A novel method of stripping (agitation) was investigated for NH{sub 3}-N removal. • PFS coagulation followed agitation process enhanced the leachate biodegradation. • Nitrification–denitrification achieved by changing operation process in SBR treatment. • A dual filter of carbon-sand is suitable as a polishing treatment of leachate. • Combined treatment success for the complete treatment of non-biodegradable leachate. - Abstract: This study describes the complete treatment of non-biodegradable landfill leachate by combined treatment processes. The processes consist of agitation as a novel stripping method used to overcome the ammonia toxicity regarding aerobic microorganisms. The NH{sub 3}-N removal ratio was 93.9% obtained at pH 11.5 and a gradient velocity (G) 150 s{sup −1} within a five-hour agitation time. By poly ferric sulphate (PFS) coagulation followed the agitation process; chemical oxygen demand (COD) and biological oxygen demand (BOD{sub 5}) were removed at 70.6% and 49.4%, respectively at an optimum dose of 1200 mg L{sup −1} at pH 5.0. The biodegradable ratio BOD{sub 5}/COD was improved from 0.18 to 0.31 during pretreatment step by agitation and PFS coagulation. Thereafter, the effluent was diluted with sewage at a different ratio before it was subjected to sequencing batch reactor (SBR) treatment. Up to 93.3% BOD{sub 5}, 95.5% COD and 98.1% NH{sub 3}-N removal were achieved by SBR operated under anoxic–aerobic–anoxic conditions. The filtration process was carried out using sand and carbon as a dual filter media as polishing process. The final effluent concentration of COD, BOD{sub 5}, suspended solid (SS), NH{sub 3}-N and total organic carbon (TOC) were 72.4 mg L{sup −1}, 22.8 mg L{sup −1}, 24.2 mg L{sup −1}, 18.4 mg L{sup −1} and 50.8 mg L{sup −1} respectively, which met the discharge standard. The results indicated that a combined process of agitation-coagulation-SBR and filtration effectively eliminated
Carbon and hydrogen isotope fractionation during aerobic biodegradation of quinoline and 3-methylquinoline.

Science.gov (United States)

Cui, Mingchao; Zhang, Wenbing; Fang, Jun; Liang, Qianqiong; Liu, Dongxuan

2017-08-01

Compound-specific isotope analysis has been used extensively to investigate the biodegradation of various organic pollutants. To date, little isotope fractionation information is available for the biodegradation of quinolinic compounds. In this study, we report on the carbon and hydrogen isotope fractionation during quinoline and 3-methylquinoline aerobic microbial degradation by a Comamonas sp. strain Q10. Degradation of quinoline and 3-methylquinoline was accompanied by isotope fractionation. Large hydrogen and small carbon isotope fractionation was observed for quinoline while minor carbon and hydrogen isotope fractionation effects occurred for 3-methylquinoline. Bulk carbon and hydrogen enrichment factors (ε bulk ) for quinoline biodegradation were -1.2 ± 0.1 and -38 ± 1‰, respectively, while -0.7 ± 0.1 and -5 ± 1‰ for 3-methylquinoline, respectively. This reveals a potential advantage for employing quinoline as the model compound and hydrogen isotope analysis for assessing aerobic biodegradation of quinolinic compounds. The apparent kinetic isotope effects (AKIE C ) values of carbon were 1.008 ± 0.0005 for quinoline and 1.0048 ± 0.0005 for 3-methylquinoline while AKIE H values of hydrogen of 1.264 ± 0.011 for quinoline and 1.0356 ± 0.0103 for 3-methylquinoline were obtained. The combined evaluation of carbon and hydrogen isotope fractionation yields Λ values (Λ = Δδ 2 H/Δδ 13 C ≈ εH bulk /εC bulk ) of 29 ± 2 for quinoline and 8 ± 2 for 3-methylquinoline. The results indicate that the substrate specificity may have a significant influence on the isotope fractionation for the biodegradation of quinolinic compounds. The substrate-specific isotope enrichment factors would be important for assessing the behavior and fate of quinolinic compounds in the environment.

Complementing approaches to demonstrate chlorinated solvent biodegradation in a complex pollution plume: mass balance, PCR and compound-specific stable isotope analysis.

OpenAIRE

Courbet Christelle; Rivière Agnès; Jeannottat Simon; Rinaldi Sandro; Hunkeler Daniel; Bendjoudi Hocine; De Marsily Ghislain

2011-01-01

This work describes the use of different complementing methods (mass balance polymerase chain reaction assays and compound specific stable isotope analysis) to demonstrate the existence and effectiveness of biodegradation of chlorinated solvents in an alluvial aquifer. The solvent contaminated site is an old chemical factory located in an alluvial plain in France. As most of the chlorinated contaminants currently found in the groundwater at this site were produced by local industries at vario...
Processing and characterization of solid and microcellular biobased and biodegradable PHBV-based polymer blends and composites

Science.gov (United States)

Javadi, Alireza

Petroleum-based polymers have made a significant contribution to human society due to their extraordinary adaptability and processability. However, due to the wide-spread application of plastics over the past few decades, there are growing concerns over depleting fossil resources and the undesirable environmental impact of plastics. Most of the petroleum-based plastics are non-biodegradable and thus will be disposed in landfills. Inappropriate disposal of plastics may also become a potential threat to the environment. Many approaches, such as efficient plastics waste management and replacing petroleum-based plastics with biodegradable materials obtained from renewable resources, have been put forth to overcome these problems. Plastics waste management is at its beginning stages of development which is also more expensive than expected. Thus, there is a growing interest in developing sustainable biobased and biodegradable materials produced from renewable resources such as plants and crops, which can offer comparable performance with additional advantages, such as biodegradability, biocompatibility, and reducing the carbon footprint. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is one of the most promising biobased and biodegradable polymers, In fact many petroleum based polymers such as poly(propylene) (PP) can be potentially replaced by PHBV because of the similarity in their properties. Despite PHBV's attractive properties, there are many drawbacks such as high cost, brittleness, and thermal instability, which hamper the widespread usage of this specific polymer. The goals of this study are to investigate various strategies to address these drawbacks, including blending with other biodegradable polymers such as poly (butylene adipate-coterephthalate) (PBAT) or fillers (e.g., coir fiber, recycled wood fiber, and nanofillers) and use of novel processing technologies such as microcellular injection molding technique. Microcellular injection molding technique
Modified hydrotalcite-like compounds as active fillers of biodegradable polymers for drug release and food packaging applications.

Science.gov (United States)

Costantino, Umberto; Nocchetti, Morena; Tammaro, Loredana; Vittoria, Vittoria

2012-11-01

This review treats the recent patents and related literature, mainly from the Authors laboratories, on biomedical and food packaging applications of nano-composites constituted of biodegradable polymers filled with micro or nano crystals of organically modified Layered Double Hydroxides of Hydrotalcite type. After a brief outline of the chemical and structural aspects of Hydrotalcite-like compounds (HTlc) and of their manipulation via intercalation of functional molecular anions to obtain materials for numerous, sometime unexpected applications, the review approaches the theme in three separated parts. Part 1 deals with the synthetic method used to prepare the pristine Mg-Al and Zn-Al HTlc and with the procedures of their functionalization with anti-inflammatory (diclofenac), antibacterial (chloramphenicol hemisuccinate), antifibrinolytic (tranexamic acid) drugs and with benzoates with antimicrobial activity. Procedures used to form (nano) composites of polycaprolactone, used as an example of biodegradable polymer, and functionalized HTlc are also reported. Part 2 discusses a patent and related papers on the preparation and biomedical use of a controlled delivery system of the above mentioned pharmacologically active substances. After an introduction dealing with the recent progress in the field of local drug delivery systems, the chemical and structural aspects of the patented system constituted of a biodegradable polymer and HTlc loaded with the active substances will be presented together with an extensive discussion of the drug release in physiological medium. Part 3 deals with a recent patent and related papers on chemical, structural and release property of antimicrobial species of polymeric films containing antimicrobial loaded HTlc able to act as active packaging for food products prolonging their shelf life.
Effect of starch types on properties of biodegradable polymer based on thermoplastic starch process by injection molding technique

Directory of Open Access Journals (Sweden)

Yossathorn Tanetrungroj

2015-04-01

Full Text Available In this study effects of different starch types on the properties of biodegradable polymer based on thermoplastic starch (TPS were investigated. Different types of starch containing different contents of amylose and amylopectin were used, i.e. cassava starch, mungbean starch, and arrowroot starch. The TPS polymers were compounded and shaped using an internal mixer and an injection molding machine, respectively. It was found that the amount of amylose and amylopectin contents on native starch influence the properties of the TPS polymer. A high amylose starch of TPMS led to higher strength, hardness, degree of crystallization than the high amylopectin starch of TPCS. In addition, function group analysis by Fourier transforms infrared spectrophotometer, water absorption, and biodegradation by soil burial test were also examined.
Preparation and Characterization of PLA-Starch Biodegradable Composites Via Radiation Processing

Energy Technology Data Exchange (ETDEWEB)

Hemvichian, K.; Suwanmala, P. [Thailand Institute of Nuclear Technology (TINT) (Thailand); Kungsumrith, W. [Department of Industrial Engineering, Faculty of Engineering, Thammasat University (TU) (Thailand); Pongprayoon, T. [Department of Chemical Engineering, Faculty of Engineering, King Mongkut’s University of Technology North Bangkok (KMUTNB), Bangkok (Thailand)

2011-07-01

This research project aims to apply the use of radiation processing to prepare biodegradable composites from poly(lactic acid) or polylactide (PLA) and cassava starch. Cassava starch, a natural polymer that is inexpensive and abundant, especially in Thailand, will be used as starting material. Functional group of cassava starch will be modified first in order to render starch more compatible with PLA. The monomer with desired functional groups will be grafted onto the backbone of starch via radiation-induced grafting polymerization. Different parameters will be examined to determine the optimum conditions for the grafting polymerization. The modified starch will subsequently be blended with PLA, with and without clay, to form biodegradable composites. In order to further improve the thermal properties, the blends and their composites will be subjected to radiation to induce crosslinking between the molecules of PLA and starch derivatives. (author)
Preparation and Characterization of PLA-Starch Biodegradable Composites Via Radiation Processing

International Nuclear Information System (INIS)

Hemvichian, K.; Suwanmala, P.; Kungsumrith, W.; Pongprayoon, T.

2011-01-01

This research project aims to apply the use of radiation processing to prepare biodegradable composites from poly(lactic acid) or polylactide (PLA) and cassava starch. Cassava starch, a natural polymer that is inexpensive and abundant, especially in Thailand, will be used as starting material. Functional group of cassava starch will be modified first in order to render starch more compatible with PLA. The monomer with desired functional groups will be grafted onto the backbone of starch via radiation-induced grafting polymerization. Different parameters will be examined to determine the optimum conditions for the grafting polymerization. The modified starch will subsequently be blended with PLA, with and without clay, to form biodegradable composites. In order to further improve the thermal properties, the blends and their composites will be subjected to radiation to induce crosslinking between the molecules of PLA and starch derivatives. (author)
Toluene biodegradation and biofilm growth in an aerobic fixed-film reactor

DEFF Research Database (Denmark)

Arcangeli, Jean-Pierre; Arvin, Erik

1992-01-01

Aerobic biodegradation of toluene in a biofilm system was investigated. Toluene is easily biodegradable, like several other aromatic compounds. The degradation was first order at bulk concentrations lower than 0.14 mg/l and zero order above 6–8 mg/l. An average yield coefficient of 1 mg biomass...
Incorporation of in silico biodegradability screening in early drug development--a feasible approach?

Science.gov (United States)

Steger-Hartmann, Thomas; Länge, Reinhard; Heuck, Klaus

2011-05-01

The concentration of a pharmaceutical found in the environment is determined by the amount used by the patient, the excretion and metabolism pattern, and eventually by its persistence. Biological degradation or persistence of a pharmaceutical is experimentally tested rather late in the development of a pharmaceutical, often shortly before submission of the dossier to regulatory authorities. To investigate whether the aspect of persistence of a compound could be assessed early during drug development, we investigated whether biodegradation of pharmaceuticals could be predicted with the help of in silico tools. To assess the value of in silico prediction, we collected results for the OECD 301 degradation test ("ready biodegradability") of 42 drugs or drug synthesis intermediates and compared them to the prediction of the in silico tool BIOWIN. Of these compounds, 38 were predictable with BIOWIN, which is a module of the Estimation Programs Interface (EPI) Suite™ provided by the US EPA. The program failed to predict the two drugs which proved to be readily biodegradable in the degradation tests. On the other hand, BIOWIN predicted two compounds to be readily biodegradable which, however, proved to be persistent in the test setting. The comparison of experimental data with the predicted one resulted in a specificity of 94% and a sensitivity of 0%. The results of this study do not indicate that application of the biodegradation prediction tool BIOWIN is a feasible approach to assess the ready biodegradability during early drug development.
Characterization of a biosurfactant produced by Pseudomonas cepacia CCT6659 in the presence of industrial wastes and its application in the biodegradation of hydrophobic compounds in soil.

Science.gov (United States)

Silva, Elias J; Rocha e Silva, Nathália Maria P; Rufino, Raquel D; Luna, Juliana M; Silva, Ricardo O; Sarubbo, Leonie A

2014-05-01

The bacterium Pseudomonas cepacia CCT6659 cultivated with 2% soybean waste frying oil and 2% corn steep liquor as substrates produced a biosurfactant with potential application in the bioremediation of soils. The biosurfactant was classified as an anionic biomolecule composed of 75% lipids and 25% carbohydrates. Characterization by proton nuclear magnetic resonance ((1)H and (13)C NMR) revealed the presence of carbonyl, olefinic and aliphatic groups, with typical spectra of lipids. Four sets of biodegradation experiments were carried out with soil contaminated by hydrophobic organic compounds amended with molasses in the presence of an indigenous consortium, as follows: Set 1-soil+bacterial cells; Set 2-soil+biosurfactant; Set 3-soil+bacterial cells+biosurfactant; and Set 4-soil without bacterial cells or biosurfactant (control). Significant oil biodegradation activity (83%) occurred in the first 10 days of the experiments when the biosurfactant and bacterial cells were used together (Set 3), while maximum degradation of the organic compounds (above 95%) was found in Sets 1-3 between 35 and 60 days. It is evident from the results that the biosurfactant alone and its producer species are both capable of promoting biodegradation to a large extent. Copyright © 2014 Elsevier B.V. All rights reserved.
Biodegradation of radioactive organic liquid waste from spent fuel reprocessing

International Nuclear Information System (INIS)

Ferreira, Rafael Vicente de Padua

2008-01-01

The research and development program in reprocessing of low burn-up spent fuel elements began in Brazil in 70's, originating the lab-scale hot cell, known as Celeste located at Nuclear and Energy Research Institute, IPEN - CNEN/SP. The program was ended at the beginning of 90's, and the laboratory was closed down. Part of the radioactive waste generated mainly from the analytical laboratories is stored waiting for treatment at the Waste Management Laboratory, and it is constituted by mixture of aqueous and organic phases. The most widely used technique for the treatment of radioactive liquid wastes is the solidification in cement matrix, due to the low processing costs and compatibility with a wide variety of wastes. However, organics are generally incompatible with cement, interfering with the hydration and setting processes, and requiring pre -treatment with special additives to stabilize or destroy them. The objective of this work can be divided in three parts: organic compounds characterization in the radioactive liquid waste; the occurrence of bacterial consortia from Pocos de Caldas uranium mine soil and Sao Sebastiao estuary sediments that are able to degrade organic compounds; and the development of a methodology to biodegrade organic compounds from the radioactive liquid waste aiming the cementation. From the characterization analysis, TBP and ethyl acetate were chosen to be degraded. The results showed that selected bacterial consortia were efficient for the organic liquid wastes degradation. At the end of the experiments the biodegradation level were 66% for ethyl acetate and 70% for the TBP. (author)
Potential for biodegradation of polycyclic aromatic hydrocarbons by ...

African Journals Online (AJOL)

WiTT

2012-05-08

May 8, 2012 ... Full Length Research Paper. Biodegradation of ... organic compounds, including some organometallic ... is a major source of toxic PAHs that contributes signi- ficantly to ... microorganisms for bioremediation of hydrocarbon-.
Biodegradation aspects of Polycyclic Aromatic Hydrocarbons (PAHs): A review

Energy Technology Data Exchange (ETDEWEB)

Haritash, A.K., E-mail: akharitash@gmail.com [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar, Haryana (India); Kaushik, C.P. [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar, Haryana (India)

2009-09-30

PAHs are aromatic hydrocarbons with two or more fused benzene rings with natural as well as anthropogenic sources. They are widely distributed environmental contaminants that have detrimental biological effects, toxicity, mutagenecity and carcinogenicity. Due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, the PAHs have gathered significant environmental concern. Although PAH may undergo adsorption, volatilization, photolysis, and chemical degradation, microbial degradation is the major degradation process. PAH degradation depends on the environmental conditions, number and type of the microorganisms, nature and chemical structure of the chemical compound being degraded. They are biodegraded/biotransformed into less complex metabolites, and through mineralization into inorganic minerals, H{sub 2}O, CO{sub 2} (aerobic) or CH{sub 4} (anaerobic) and rate of biodegradation depends on pH, temperature, oxygen, microbial population, degree of acclimation, accessibility of nutrients, chemical structure of the compound, cellular transport properties, and chemical partitioning in growth medium. A number of bacterial species are known to degrade PAHs and most of them are isolated from contaminated soil or sediments. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Lignolytic fungi too have the property of PAH degradation. Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus are the common PAH-degrading fungi. Enzymes involved in the degradation of PAHs are oxygenase, dehydrogenase and lignolytic enzymes. Fungal lignolytic enzymes are lignin peroxidase, laccase, and manganese peroxidase. They are extracellular and catalyze radical formation by oxidation to destabilize bonds in a molecule. The biodegradation of PAHs has been observed under both aerobic and anaerobic conditions
Biodegradation aspects of Polycyclic Aromatic Hydrocarbons (PAHs): A review

International Nuclear Information System (INIS)

Haritash, A.K.; Kaushik, C.P.

2009-01-01

PAHs are aromatic hydrocarbons with two or more fused benzene rings with natural as well as anthropogenic sources. They are widely distributed environmental contaminants that have detrimental biological effects, toxicity, mutagenecity and carcinogenicity. Due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, the PAHs have gathered significant environmental concern. Although PAH may undergo adsorption, volatilization, photolysis, and chemical degradation, microbial degradation is the major degradation process. PAH degradation depends on the environmental conditions, number and type of the microorganisms, nature and chemical structure of the chemical compound being degraded. They are biodegraded/biotransformed into less complex metabolites, and through mineralization into inorganic minerals, H 2 O, CO 2 (aerobic) or CH 4 (anaerobic) and rate of biodegradation depends on pH, temperature, oxygen, microbial population, degree of acclimation, accessibility of nutrients, chemical structure of the compound, cellular transport properties, and chemical partitioning in growth medium. A number of bacterial species are known to degrade PAHs and most of them are isolated from contaminated soil or sediments. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Lignolytic fungi too have the property of PAH degradation. Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus are the common PAH-degrading fungi. Enzymes involved in the degradation of PAHs are oxygenase, dehydrogenase and lignolytic enzymes. Fungal lignolytic enzymes are lignin peroxidase, laccase, and manganese peroxidase. They are extracellular and catalyze radical formation by oxidation to destabilize bonds in a molecule. The biodegradation of PAHs has been observed under both aerobic and anaerobic conditions and the rate can
ANAEROBIC BIODEGRADATION OF A BIODEGRADABLE MATERIAL UNDER ANAEROBIC - THERMOPHILIC DIGESTION

Directory of Open Access Journals (Sweden)

RICARDO CAMACHO-MUÑOZ

2014-12-01

Full Text Available This paper dertermined the anaerobic biodegradation of a polymer obtained by extrusion process of native cassava starch, polylactic acid and polycaprolactone. Initially a thermophilic - methanogenic inoculum was prepared from urban solid waste. The gas final methane concentration and medium’s pH reached values of 59,6% and 7,89 respectively. The assay assembly was carried out according ASTM D5511 standard. The biodegradation percent of used materials after 15 day of digestion were: 77,49%, 61,27%, 0,31% for cellulose, sample and polyethylene respectively. Due cellulose showed biodegradation levels higher than 70% it’s deduced that the inoculum conditions were appropriate. A biodegradation level of 61,27%, 59,35% of methane concentration in sample’s evolved gas and a medium’s finale pH of 7,71 in sample’s vessels, reveal the extruded polymer´s capacity to be anaerobically degraded under thermophilic- high solid concentration conditions.
Biodegradation of benzotriazoles and hydroxy-benzothiazole in wastewater by activated sludge and moving bed biofilm reactor systems

DEFF Research Database (Denmark)

Mazioti, Aikaterini A.; Stasinakis, Athanasios S.; Pantazi, Ypapanti

2015-01-01

Two laboratory scale fully aerated continuous flow wastewater treatment systems were used to compare the removal of five benzotriazoles and one benzothiazole by suspended and attached growth biomass. The Activated Sludge system was operated under low organic loading conditions. The Moving Bed...... in significantly lower biodegradation for 4 out of 6 examined compounds. Calculation of specific removal rates (normalised to biomass) revealed that attached biomass had higher biodegradation potential for target compounds comparing to suspended biomass. Clear differences in the biodegradation ability of attached...... biomass grown in different bioreactors of MBBR systems were also observed. Batch experiments showed that micropollutants biodegradation by both types of biomass is co-metabolic....
Biodegradation of clofibric acid and identification of its metabolites

International Nuclear Information System (INIS)

Salgado, R.; Oehmen, A.; Carvalho, G.; Noronha, J.P.; Reis, M.A.M.

2012-01-01

Graphical abstract: Metabolites produced during clofibric acid biodegradation. Highlights: ► Clofibric acid is biodegradable. ► Mainly heterotrophic bacteria degraded the clofibric acid. ► Metabolites of clofibric acid biodegradation were identified. ► The metabolic pathway of clofibric acid biodegradation is proposed. - Abstract: Clofibric acid (CLF) is the pharmaceutically active metabolite of lipid regulators clofibrate, etofibrate and etofyllinclofibrate, and it is considered both environmentally persistent and refractory. This work studied the biotransformation of CLF in aerobic sequencing batch reactors (SBRs) with mixed microbial cultures, monitoring the efficiency of biotransformation of CLF and the production of metabolites. The maximum removal achieved was 51% biodegradation (initial CLF concentration = 2 mg L −1 ), where adsorption and abiotic removal mechanisms were shown to be negligible, showing that CLF is indeed biodegradable. Tests showed that the observed CLF biodegradation was mainly carried out by heterotrophic bacteria. Three main metabolites were identified, including α-hydroxyisobutyric acid, lactic acid and 4-chlorophenol. The latter is known to exhibit higher toxicity than the parent compound, but it did not accumulate in the SBRs. α-Hydroxyisobutyric acid and lactic acid accumulated for a period, where nitrite accumulation may have been responsible for inhibiting their degradation. A metabolic pathway for the biodegradation of CLF is proposed in this study.
Biodegradation of Para Amino Acetanilide by Halomonas sp. TBZ3.

Science.gov (United States)

Hajizadeh, Nader; Sefidi Heris, Youssof; Zununi Vahed, Sepideh; Vallipour, Javad; Hejazi, Mohammad Amin; Golabi, Sayyed Mahdi; Asadpour-Zeynali, Karim; Hejazi, Mohammad Saeid

2015-09-01

Aromatic compounds are known as a group of highly persistent environmental pollutants. Halomonas sp. TBZ3 was isolated from the highly salty Urmia Lake of Iran. In this study, characterization of a new Halomonas isolate called Halomonas sp. TBZ3 and its employment for biodegradation of para-amino acetanilide (PAA), as an aromatic environmental pollutant, is described. This study aimed to characterize the TBZ3 isolate and to elucidate its ability as a biodegradative agent that decomposes PAA. Primarily, DNA-DNA hybridization between TBZ3, Halomonas denitrificans DSM18045T and Halomonas saccharevitans LMG 23976T was carried out. Para-amino acetanilide biodegradation was assessed using spectrophotometry and confirmed by gas chromatography-mass spectroscopy (GC-MS). Parameters effective on biodegradation of PAA were optimized by the Response Surface Methodology (RSM). The DNA-DNA hybridization experiments between isolate TBZ3, H. denitrificans and H. saccharevitans revealed relatedness levels of 57% and 65%, respectively. According to GC-MS results, TBZ3 degrades PAA to benzene, hexyl butanoate, 3-methyl-1-heptanol and hexyl hexanoate. Temperature 32.92°C, pH 6.76, and salinity 14% are the optimum conditions for biodegradation with a confidence level of 95% (at level α = 0.05). According to our results, Halomonas sp. TBZ3 could be considered as a biological agent for bioremediation of PAA and possibly other similar aromatic compounds.
Simulation of DEHP biodegradation and sorption during the anaerobic digestion of secondary sludge

DEFF Research Database (Denmark)

Fountoulakis, M.S.; Stamatelatou, K.; Batstone, Damien J.

2006-01-01

-limiting for the compound biodegradation. In this study, the anaerobic biodegradation of DEHP was investigated through batch kinetic experiments and dynamic transitions of a continuous stirred tank reactor (CSTR) fed with secondary sludge contaminated with DEHP. A widely accepted model (ADM1) was used to fit the anaerobic......" against biodegradation. The model, fitted to the batch experimental data, was able to predict DEHP removal in the CSTR operated at various HRTs....
Enzymes of Candida tropicalis yeast biodegrading phenol

OpenAIRE

Koubková, Zuzana

2011-01-01

Effluents of industrial wastewaters from oil refineries, paper mills, dyes, ceramic factories, resins, textiles and plastic contain high concentrations of aromatic compounds, which are toxic to organisms. Degradation of these compounds to tolerant limits before releasing them into the environment is an urgent requirement. Candida tropicalis yeast is an important representative of eucaryotic microorganisms that are able to utilize phenol. During the first phase of phenol biodegradation, cytopl...
Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

Science.gov (United States)

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

2013-01-01

Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

Directory of Open Access Journals (Sweden)

José Maria Rodrigues da Luz

Full Text Available Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.
Degradation of Oxo-Biodegradable Plastic by Pleurotus ostreatus

Science.gov (United States)

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

2013-01-01

Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate. PMID:23967057
Preparation and performance of Ecobras/bentonite biodegrading films

International Nuclear Information System (INIS)

Costa, Ana Nery M.; Melo, Nadja M.C.; Canedo, Eduardo L.; Carvalho, Laura H.; Araujo, Arthur R.A.

2011-01-01

Compounds based on the biodegradable polymer Ecobras and bentonite clay in its pristine, sonicated, and organically modified with a quaternary ammonium salt forms were prepared as flat films. Clays and compounds were characterized by x-ray diffraction and scanning electron microscopy. Mechanical properties of the films were determined according to pertinent ASTM standards. Reasonable properties, higher than those of the matrix, were obtained with compounds prepared with purified clays and organoclays, particularly for low clay loading. (author)
Biodegradation Rates of Aromatic Contaminants in Biofilm Reactors

DEFF Research Database (Denmark)

Arcangeli, Jean-Pierre; Arvin, Erik

1995-01-01

This study has shown that microorganisms can adapt to degrade mixtures of aromatic pollutants at relatively high rates in the μg/l concentration range. The biodegradation rates of the following compounds were investigated in biofilm systems: aromatic hydrocarbons, phenol, methylphenols......-reducing conditions, toluene was easily biodegraded. The xylenes and ethylbenzene were degraded cometabolically if toluene was used as a primary carbon source; their removal was influenced by competitive inhibition with toluene. These interaction phenomena are discussed in this paper and a kinetic model taking...
WWTP respirometric application. Toxicity and biodegradability studies

International Nuclear Information System (INIS)

Aguilar Sanchis, M. I.; Llorens Pascual del Riquelme, M.; Meseguer Zapata, V. F.; Ortuno Sandoval, J.; Perez martin, A. B.; Saez Mercader, J.

2009-01-01

Respirometry is the measurements of the oxygen consumption of microorganisms present in activated sludge, which can be related to both biomass growth and substrate consumption to obtain energy. Yh parameter (biomass/substrate yield), denominated heterotrophic biomass yield coefficient, express the portion of substrate transformed to biomass. eight municipal wastewater treatment plants (WWTP) with different activated sludge biological treatment were selected to study wastewater biodegradability by measuring respiration rate in dynamic mode. The selection of the WWTP was based on the aeration system operating in the biological reactor. Besides, the effect of heavy metals and some organic compounds on biological process has been studied. (Author) 12 refs.
Combined thermophilic aerobic process and conventional anaerobic digestion: effect on sludge biodegradation and methane production.

Science.gov (United States)

Dumas, C; Perez, S; Paul, E; Lefebvre, X

2010-04-01

The efficiency of hyper-thermophilic (65 degrees Celsius) aerobic process coupled with a mesophilic (35 degrees Celsius) digester was evaluated for the activated sludge degradation and was compared to a conventional mesophilic digester. For two Sludge Retention Time (SRT), 21 and 42 days, the Chemical Oxygen Demand (COD) solubilisation and biodegradation processes, the methanisation yield and the aerobic oxidation were investigated during 180 days. The best results were obtained at SRT of 44 days; the COD removal yield was 30% higher with the Mesophilic Anaerobic Digestion/Thermophilic Aerobic Reactor (MAD-TAR) co-treatment. An increase of the sludge intrinsic biodegradability is also observed (20-40%), showing that the unbiodegradable COD in mesophilic conditions becomes bioavailable. However, the methanisation yield was quite similar for both processes at a same SRT. Finally, such a process enables to divide by two the volume of digester with an equivalent efficiency. Copyright 2009 Elsevier Ltd. All rights reserved.
Biodegradation of clofibric acid and identification of its metabolites

Energy Technology Data Exchange (ETDEWEB)

Salgado, R. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); ESTS-IPS, Escola Superior de Tecnologia de Setubal do Instituto Politecnico de Setubal, Rua Vale de Chaves, Campus do IPS, Estefanilha, 2910-761 Setubal (Portugal); Oehmen, A. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Carvalho, G. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Instituto de Biologia Experimental e Tecnologica (IBET), Av. da Republica (EAN), 2784-505 Oeiras (Portugal); Noronha, J.P. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Reis, M.A.M., E-mail: amr@fct.unl.pt [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

2012-11-30

Graphical abstract: Metabolites produced during clofibric acid biodegradation. Highlights: Black-Right-Pointing-Pointer Clofibric acid is biodegradable. Black-Right-Pointing-Pointer Mainly heterotrophic bacteria degraded the clofibric acid. Black-Right-Pointing-Pointer Metabolites of clofibric acid biodegradation were identified. Black-Right-Pointing-Pointer The metabolic pathway of clofibric acid biodegradation is proposed. - Abstract: Clofibric acid (CLF) is the pharmaceutically active metabolite of lipid regulators clofibrate, etofibrate and etofyllinclofibrate, and it is considered both environmentally persistent and refractory. This work studied the biotransformation of CLF in aerobic sequencing batch reactors (SBRs) with mixed microbial cultures, monitoring the efficiency of biotransformation of CLF and the production of metabolites. The maximum removal achieved was 51% biodegradation (initial CLF concentration = 2 mg L{sup -1}), where adsorption and abiotic removal mechanisms were shown to be negligible, showing that CLF is indeed biodegradable. Tests showed that the observed CLF biodegradation was mainly carried out by heterotrophic bacteria. Three main metabolites were identified, including {alpha}-hydroxyisobutyric acid, lactic acid and 4-chlorophenol. The latter is known to exhibit higher toxicity than the parent compound, but it did not accumulate in the SBRs. {alpha}-Hydroxyisobutyric acid and lactic acid accumulated for a period, where nitrite accumulation may have been responsible for inhibiting their degradation. A metabolic pathway for the biodegradation of CLF is proposed in this study.
Nanocomposites Based on Biodegradable Polymers

Directory of Open Access Journals (Sweden)

Ilaria Armentano

2018-05-01

Full Text Available In the present review paper, our main results on nanocomposites based on biodegradable polymers (on a time scale from 2010 to 2018 are reported. We mainly focused our attention on commercial biodegradable polymers, which we mixed with different nanofillers and/or additives with the final aim of developing new materials with tunable specific properties. A wide list of nanofillers have been considered according to their shape, properties, and functionalization routes, and the results have been discussed looking at their roles on the basis of different adopted processing routes (solvent-based or melt-mixing processes. Two main application fields of nanocomposite based on biodegradable polymers have been considered: the specific interaction with stem cells in the regenerative medicine applications or as antimicrobial materials and the active role of selected nanofillers in food packaging applications have been critically revised, with the main aim of providing an overview of the authors’ contribution to the state of the art in the field of biodegradable polymeric nanocomposites.
Biodegradation studies of selected priority acidic pesticides and diclofenac in different bioreactors

International Nuclear Information System (INIS)

Gonzalez, Susana; Mueller, Jutta; Petrovic, Mira; Barcelo, Damia; Knepper, Thomas P.

2006-01-01

The biodegradation of selected priority acidic pesticides MCPP, MCPA, 2,4-D, 2,4-DP and bentazone and the acidic pharmaceutical diclofenac was investigated using a membrane bioreactor (MBR) and a fixed-bed bioreactor (FBBR). A pilot plant MBR was fed with raw water spiked with the selected compounds. The experiment was repeated every week during four weeks to enhance the adaptation of microorganisms. In order to further study the biodegradability of these compounds, degradation studies in a FBBR were carried out. All the samples were analysed by solid phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS). The results indicate that in the MBR compounds except for bentazone were eliminated within the first day of the experiment at rates ranging from 44% to 85%. Comparing these results with the degradation rates in the FBBR showed that in the latter only MCPP, MCPA 2,4-D and 2,4-DP were degraded after a much longer adaptation phase of microorganisms. - Biodegradation rate of selected acidic pesticides and pharmaceuticals depends on adaptation
Petroleum biodegradation and oil spill bioremediation

International Nuclear Information System (INIS)

Atlas, R.M.

1995-01-01

Hydrocarbon-utilizing microorganisms are ubiquitously distributed in the marine environment following oil spills. These microorganisms naturally biodegrade numerous contaminating petroleum hydrocarbons, thereby cleansing the oceans of oil pullutants. Bioremediation, which is accomplished by adding exogenous microbial populations or stimulating indigenous ones, attempts to raise the rates of degradation found naturally to significantly higher rates. Seeding with oil degraders has not been demonstrated to be effective, but addition of nitrogenous fertilizers has been shown to increase rates of petroleum biodegradation. In the case of the Exxon Valdez spill, the largest and most thoroughly studied application of bioremediation, the application of fertilizer (slow release or oleophilic) increased rates of biodegradation 3-5 times. Because of the patchiness of oil, an internally conserved compound, hopane, was critical for demonstrating the efficacy of bioremediation. Multiple regression models showed that the effectiveness of bioremediation depended upon the amount of nitrogen delivered, the concentration of oil, and time. (author)
Occurrence and fate of antibiotic, analgesic/anti-inflammatory, and antifungal compounds in five wastewater treatment processes.

Science.gov (United States)

Guerra, P; Kim, M; Shah, A; Alaee, M; Smyth, S A

2014-03-01

The presence of pharmaceuticals and personal care products (PPCPs) in the aquatic environment as a result of wastewater effluent discharge is a concern in many countries. In order to expand our understanding on the occurrence and fate of PPCPs during wastewater treatment processes, 62 antibiotic, analgesic/anti-inflammatory, and antifungal compounds were analyzed in 72 liquid and 24 biosolid samples from six wastewater treatment plants (WWTPs) during the summer and winter seasons of 2010-2012. This is the first scientific study to compare five different wastewater treatment processes: facultative and aerated lagoons, chemically-enhanced primary treatment, secondary activated sludge, and advanced biological nutrient removal. PPCPs were detected in all WWTP influents at median concentrations of 1.5 to 92,000 ng/L, with no seasonal differences. PPCPs were also found in all final effluents at median levels ranging from 3.6 to 4,200 ng/L with higher values during winter (pRemoval efficiencies ranged between -450% and 120%, depending on the compound, WWTP type, and season. Mass balance showed that the fate of analgesic/anti-inflammatory compounds was predominantly biodegradation during biological treatment, while antibiotics and antifungal compounds were more likely to sorb to sludge. However, some PPCPs remained soluble and were detected in effluent samples. Overall, this study highlighted the occurrence and behavior of a large set of PPCPs and determined how their removal is affected by environmental/operational factors in different WWTPs. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.
Laboratory evidence of MTBE biodegradation in Borden aquifer material

Science.gov (United States)

Schirmer, Mario; Butler, Barbara J.; Church, Clinton D.; Barker, James F.; Nadarajah, Nalina

2003-02-01

Mainly due to intrinsic biodegradation, monitored natural attenuation can be an effective and inexpensive remediation strategy at petroleum release sites. However, gasoline additives such as methyl tert-butyl ether (MTBE) can jeopardize this strategy because these compounds often degrade, if at all, at a slower rate than the collectively benzene, toluene, ethylbenzene and the xylene (BTEX) compounds. Investigation of whether a compound degrades under certain conditions, and at what rate, is therefore important to the assessment of the intrinsic remediation potential of aquifers. A natural gradient experiment with dissolved MTBE-containing gasoline in the shallow, aerobic sand aquifer at Canadian Forces Base (CFB) Borden (Ontario, Canada) from 1988 to 1996 suggested that biodegradation was the main cause of attenuation for MTBE within the aquifer. This laboratory study demonstrates biologically catalyzed MTBE degradation in Borden aquifer-like environments, and so supports the idea that attenuation due to biodegradation may have occurred in the natural gradient experiment. In an experiment with batch microcosms of aquifer material, three of the microcosms ultimately degraded MTBE to below detection, although this required more than 189 days (or >300 days in one case). Failure to detect the daughter product tert-butyl alcohol (TBA) in the field and the batch experiments could be because TBA was more readily degradable than MTBE under Borden conditions.
Characterization and biodegradation of polycyclic aromatic hydrocarbons in radioactive wastewater

International Nuclear Information System (INIS)

Tikilili, Phumza V.; Nkhalambayausi-Chirwa, Evans M.

2011-01-01

Highlights: → Biodegradation of recalcitrant toxic organics under radioactive conditions. → Biodegradation of PAHs of varying size and complexity in mixed waste streams. → Validation of radiation-tolerance and performance of the isolated organisms. - Abstract: PAH degrading Pseudomonad and Alcaligenes species were isolated from landfill soil and mine drainage in South Africa. The isolated organisms were mildly radiation tolerant and were able to degrade PAHs in simulated nuclear wastewater. The radiation in the simulated wastewater, at 0.677 Bq/μL, was compatible to measured values in wastewater from a local radioisotope manufacturing facility, and was enough to inhibit metabolic activity of known PAH degraders from soil such as Pseudomonas putida GMP-1. The organic constituents in the original radioactive waste stream consisted of the full range of PAHs except fluoranthene. Among the observed PAHs in the nuclear wastewater from the radioisotope manufacturing facility, acenaphthene and chrysene predominated-measured at 25.1 and 14.2 mg/L, respectively. Up to sixteen U.S.EPA priority PAHs were detected at levels higher than allowable limits in drinking water. The biodegradation of the PAHs was limited by the solubility of the compounds. This contributed to the observed faster degradation rates in low molecular weight (LMW) compounds than in high molecular weight compounds.
Performance Evaluation of AOP/Biological Hybrid System for Treatment of Recalcitrant Organic Compounds

Directory of Open Access Journals (Sweden)

Stanford S. Makgato

2010-01-01

Full Text Available Process water from nuclear fuel recovery unit operations contains a variety of toxic organic compounds. The use of decontamination reagents such as CCl4 together with phenolic tar results in wastewater with a high content of chlorophenols. In this study, the extent of dehalogenation of toxic aromatic compounds was evaluated using a photolytic advanced oxidation process (AOP followed by biodegradation in the second stage. A hard-to-degrade toxic pollutant, 4-chlorophenol (4-CP, was used to represent a variety of recalcitrant aromatic pollutants in effluent from the nuclear industry. A UV-assisted AOP/bioreactor system demonstrated a great potential in treatment of nuclear process wastewater and this was indicated by high removal efficiency (>98% under various 4-CP concentrations. Adding hydrogen peroxide (H2O2 as a liquid catalyst further improved biodegradation rate but the effect was limited by the scavenging of OH• radicals under high concentrations of H2O2.
Application of H2O and UV/H2O2 processes for enhancing the biodegradability of reactive black 5 dye.

Science.gov (United States)

Kalpana, S Divya; Kalyanaraman, Chitra; Gandhi, N Nagendra

2011-07-01

Leather processing is a traditional activity in India during which many organic and inorganic chemicals are added while part of it is absorbed by the leather, the remaining chemicals are discharged along with the effluent. The effluent contains both easily biodegradable and not easily biodegradable synthetic organics like dyes, syntans. Easily biodegradable organics are removed in the existing biological treatment units whereas synthetic organics present in the wastewater are mostly adsorbed over the microbes. As the tannery effluent contains complex chemicals, it is difficult to ascertain the degradation of specific pollutants. To determine the increase in the biodegradability, one of the complex and synthetic organic chemical like dye used in the tanning operation was selected for Advanced Oxidation Process (AOPs) treatment for cleaving complex organics and its subsequent treatment in aerobic process. In the present study, Reactive Black 5 Dye used in the tanning operation was selected for Hydrogen Peroxide (H2O2) and UV/H2O2 pre-treatment for different operating conditions like pH, contact time and different volume of H2O2. A comparison was made between the untreated, Hydrogen Peroxide (H2O2) and UV/H2O2 treated effluent in order to ascertain the influence of AOP on the improvement of biodegradability of effluent. An increase in the BOD5/COD ratio from 0.21 to 0.435 was achieved in the UV/H2O2 pre-treatment process. This pre-treated effluent was further subjected to aerobic process. Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) removal efficiency of the UV/H2O2 pre-treated dye solution in the aerobic process was found to be 86.39% and 77.82% when compared to 52.43% of BOD5 and 51.55% of COD removal efficiency without any pre-treatment. Hence from these results, to increase the biodegradability of Reactive Black 5 dye pre-treatment methods like H2O2 and UV/H2O2 can be used prior to biological treatment process.
Anaerobic biodegradation of dissolved ethanol in a pilot-scale sand aquifer: Variability in plume (redox) biogeochemistry

Science.gov (United States)

McLeod, Heather C.; Roy, James W.; Slater, Gregory F.; Smith, James E.

2018-01-01

The use of ethanol in alternative fuels has led to contamination of groundwater with high concentrations of this easily biodegradable organic compound. Previous laboratory and field studies have shown vigorous biodegradation of ethanol plumes, with prevalence of reducing conditions and methanogenesis. The objective of this study was to further our understanding of the dynamic biogeochemistry processes, especially dissolved gas production, that may occur in developing and aging plume cores at sites with ethanol or other organic contamination of groundwater. The experiment performed involved highly-detailed spatial and temporal monitoring of ethanol biodegradation in a 2-dimensional (175 cm high × 525 cm long) sand aquifer tank for 330 days, with a vertical shift in plume position and increased nutrient inputs occurring at Day 100. Rapid onset of fermentation, denitrification, sulphate-reduction and iron(III)-reduction occurred following dissolved ethanol addition, with the eventual widespread development of methanogenesis. The detailed observations also demonstrate a redox zonation that supports the plume fringe concept, secondary reactions resulting from a changing/moving plume, and time lags for the various biodegradation processes. Additional highlights include: i) the highest dissolved H2 concentrations yet reported for groundwater, possibly linked to vigorous fermentation in the absence of common terminal electron-acceptors (i.e., dissolved oxygen, nitrate, and sulphate, and iron(III)-minerals) and methanogenesis; ii) evidence of phosphorus nutrient limitation, which stalled ethanol biodegradation and perhaps delayed the onset of methanogenesis; and iii) the occurrence of dissimilatory nitrate reduction to ammonium, which has not been reported for ethanol biodegradation to date.
Biodegradation of ibuprofen, diclofenac and carbamazepine in nitrifying activated sludge under 12 °C temperature conditions

Energy Technology Data Exchange (ETDEWEB)

Kruglova, Antonina; Ahlgren, Pia; Korhonen, Nasti; Rantanen, Pirjo; Mikola, Anna; Vahala, Riku

2014-11-15

Pharmaceuticals constitute a well-known group of emerging contaminants with an increasing significance in water pollution. This study focuses on three pharmaceuticals extensively used in Finland and which can be found in environmental waters: ibuprofen, diclofenac and carbamazepine. Biodegradation experiments were conducted in a full-scale Wastewater Treatment Plant (WWTP) and in laboratory-scale Sequencing Batch Reactors (SBRs). The SBRs were operated at 12 °C, with a sludge retention time (SRT) 10–12 d and organic loading rates (OLRs) of 0.17, 0.27 and 0.33 kg BOD{sub 7} m{sup -3}d{sup -1}. Ibuprofen was found to biodegrade up to 99%. The biodegradation rate constants (k{sub biol}) for ibuprofen were calculated for full-scale and laboratory processes as well as under different laboratory conditions and found to differ from 0.9 up to 5.0 l g{sub SS}{sup −1} d{sup −1}. Diclofenac demonstrated an unexpected immediate drop of concentration in three SBRs and partial recovery of the initial concentration in one of the reactors. High fluctuating in diclofenac concentration was presumably caused by removal of this compound under different concentrations of nitrites during development of nitrifying activated sludge. Carbamazepine showed no biodegradation in all the experiments. - Highlights: • The biodegradation of three pharmaceuticals examined under 12 °C conditions. • k{sub biol} constants for ibuprofen proposed for full-scale and laboratory-scale processes. • Influence of OLR on ibuprofen biodegradation was studied. • Removal followed by recovery of diclofenac detected in nitrifying activated sludge.
Biodegradation of ibuprofen, diclofenac and carbamazepine in nitrifying activated sludge under 12 °C temperature conditions

International Nuclear Information System (INIS)

Kruglova, Antonina; Ahlgren, Pia; Korhonen, Nasti; Rantanen, Pirjo; Mikola, Anna; Vahala, Riku

2014-01-01

Pharmaceuticals constitute a well-known group of emerging contaminants with an increasing significance in water pollution. This study focuses on three pharmaceuticals extensively used in Finland and which can be found in environmental waters: ibuprofen, diclofenac and carbamazepine. Biodegradation experiments were conducted in a full-scale Wastewater Treatment Plant (WWTP) and in laboratory-scale Sequencing Batch Reactors (SBRs). The SBRs were operated at 12 °C, with a sludge retention time (SRT) 10–12 d and organic loading rates (OLRs) of 0.17, 0.27 and 0.33 kg BOD 7 m -3 d -1 . Ibuprofen was found to biodegrade up to 99%. The biodegradation rate constants (k biol ) for ibuprofen were calculated for full-scale and laboratory processes as well as under different laboratory conditions and found to differ from 0.9 up to 5.0 l g SS −1 d −1 . Diclofenac demonstrated an unexpected immediate drop of concentration in three SBRs and partial recovery of the initial concentration in one of the reactors. High fluctuating in diclofenac concentration was presumably caused by removal of this compound under different concentrations of nitrites during development of nitrifying activated sludge. Carbamazepine showed no biodegradation in all the experiments. - Highlights: • The biodegradation of three pharmaceuticals examined under 12 °C conditions. • k biol constants for ibuprofen proposed for full-scale and laboratory-scale processes. • Influence of OLR on ibuprofen biodegradation was studied. • Removal followed by recovery of diclofenac detected in nitrifying activated sludge
Monitoring biodegradation of hydrocarbons by stable isotope fractionation

Science.gov (United States)

Dorer, Conrad; Fischer, Anko; Herrmann, Steffi; Richnow, Hans-Hermann; Vogt, Carsten

2010-05-01

In the last decade, several studies have demonstrated that stable isotope tools are highly applicable for monitoring anaerobic biodegradation processes. An important methodological approach is to characterize distinct degradation pathways with respect to the specific mechanism of C-H-bond cleavage and to quantify the extent of biodegradation by compound specific isotope analysis (CSIA). Here, enrichment factors (ɛbulk) needed for a CSIA field site approach must be determined in laboratory reference experiments. Recent research results from different laboratories have shown that single ɛbulk values for similar degradation pathways can be highly variable; thus, the use of two-dimensional compound specific isotope analysis (2D-CSIA) has been encouraged for characterizing biodegradation pathways more precisely. 2D-CSIA for hydrocarbons can be expressed by the slope of the linear regression for hydrogen versus carbon discrimination known as lambda ≈ ɛHbulk/ɛCbulk. We determined the carbon and hydrogen isotope fractionation for the biodegradation of benzene, toluene and xylenes by various reference cultures. Specific enzymatic reactions initiating different biodegradation pathways could be distinguished by 2D-CSIA. For the aerobic di- and monohydroxylation of the benzene ring, lambda values always lower than 9 were observed. Enrichment cultures degrading benzene anaerobically produced significant different values: lambda values between 8-19 were oberved for nitrate-reducing consortia, whereas sulfate-reducing and methanogenic consortia showed always lambda values greater than 20 [1,2]. The observed variations suggest that (i) aerobic benzene biodegradation can be distinguished from anaerobic biodegradation, and (ii) that more than a single mechanism seems to exist for the activation of benzene under anoxic conditions. lambda values for anaerobic toluene degradation initiated by the enzyme benzylsuccinate synthase (BSS) ranged from 4 to 41, tested with strains using
Biodegradation of polycyclic aromatic hydrocarbons, selection and dynamics of bacterial populations in the rhizosphere in relation with the distance to roots; Biodegradation des Hydrocarbures Aromatiques Polycycliques, selection et dynamique des populations bacteriennes dans la rhizosphere en fonction de la distance aux racines

Energy Technology Data Exchange (ETDEWEB)

Corgie, St.

2004-03-01

The biodegradation of Polycyclic Aromatic Hydrocarbons (PAH) is mainly performed by microorganisms that can use these compounds as sole source of carbon and energy. Such capacity has been amply studied to use and optimise microbial activity for remediation of contaminated soils. The use of plants has been suggested to increase and accelerate biodegradation rate by improving microbial activity. However, biodegradation mechanisms still remain poorly described as the interactions between plant, pollutant and rhizosphere microflora are often complex. A simplified compartmented device was developed to study rhizospheric processes, especially biodegradation of PAH, as a function of distance to roots, where root exudates and/or PAH were the only carbon sources for microbial growth. The development and use of bio-molecular techniques (nucleic acid isolation, PCR, RT-PCR, TGGE, hybridization with a degradation gene specific probe) permitted to follow the structure of bacterial communities. Gradients of phenanthrene biodegradation were observed as a function of distance to roots, in parallel to spatial and temporal variations in bacterial community structure. These bacterial communities, as well as PAH biodegradation rate, also depended on the aromaticity of PAH and were modified by the symbiosis between plant and an arbuscular mycorrhizal fungus. (author)

The effectiveness of the biodegradation of raw and processed polystyrene by mealworms

Science.gov (United States)

Leluk, Karol; Hanus-Lorenz, Beata; Rybak, Justyna; Bożek, Magdalena

2017-11-01

In our studies biodegradation of four variants of polystyrene was performed. We tested: raw material (PS), processed polystyrene (PSr), building insulation material (EPS) and food packaging boxes (PSp). Materials were characterized by means melt flow ratio (MFR), shore hardness and gloss. The biochemical assessment of macromolecules (proteins, lipids and sugars) in the mealworms organisms fed with tested forms of polystyrene allowed us to set how efficient and beneficial the biodegradation of types of polystyrene is. We also evaluated the variability of bacterial community in larval guts by the use of denaturing gradient gel electrophoresis (DGGE) on the bacterial DNA of 16S rRNA genes amplified in polymerase chain reaction (PCR). The results suggest that EPS and PSp polystyrene are the most digestible for T. molitor larvae. The metabolic degradation of polystyrene is probably strictly connected with the changes in biodiversity of gut bacteria.
The effectiveness of the biodegradation of raw and processed polystyrene by mealworms

Directory of Open Access Journals (Sweden)

Leluk Karol

2017-01-01

Full Text Available In our studies biodegradation of four variants of polystyrene was performed. We tested: raw material (PS, processed polystyrene (PSr, building insulation material (EPS and food packaging boxes (PSp. Materials were characterized by means melt flow ratio (MFR, shore hardness and gloss. The biochemical assessment of macromolecules (proteins, lipids and sugars in the mealworms organisms fed with tested forms of polystyrene allowed us to set how efficient and beneficial the biodegradation of types of polystyrene is. We also evaluated the variability of bacterial community in larval guts by the use of denaturing gradient gel electrophoresis (DGGE on the bacterial DNA of 16S rRNA genes amplified in polymerase chain reaction (PCR. The results suggest that EPS and PSp polystyrene are the most digestible for T. molitor larvae. The metabolic degradation of polystyrene is probably strictly connected with the changes in biodiversity of gut bacteria.
Biotransformation of natural gas and oil compounds associated with marine oil discharges.

Science.gov (United States)

Brakstad, Odd Gunnar; Almås, Inger K; Krause, Daniel Franklin

2017-09-01

Field data from the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico (GoM) suggested that oxidation of gas compounds stimulated biodegradation of oil compounds in the deep sea plume. We performed experiments with local seawater from a Norwegian fjord to examine if the presence of dissolved gas compounds (methane, ethane and propane) affected biodegradation of volatile oil compounds, and if oil compounds likewise affected gas compound oxidation. The results from the experiment showed comparable oil compound biotransformation rates in seawater at 5 °C between seawater with and without soluble gases. Gas oxidation was not affected by the presence of volatile oil compounds. Contrary to DWH deep sea plume data, propane oxidation was not faster than methane oxidation. These data may reflect variations between biodegradation of oil and gas in seawater environments with different history of oil and gas exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.
Concept of Compound Retention Time for Organic Micro Pollutants in Anaerobic Membrane Bioreactor with Nanofiltration

KAUST Repository

Pan, Jiangjiang

2011-01-01

to control OMPs wastage. An innovative hybrid process, anaerobic membrane bioreactor with nanofiltration (AnMBR-NF), in which enhanced OMPs removal is possible based on the concept of compound retention time (CRT) through coupling anaerobic biodegradation
Improvement of biodegradability of industrial wastewaters by radiation treatment

International Nuclear Information System (INIS)

Jo, H.J.; Kim, H.J.; Kim, J.G.; Jung, J.; Choi, J.S.; Park, Y.K.

2006-01-01

In order to evaluate the use of gamma-ray treatment as a pretreatment to conventional biological methods, the effects of gamma-irradiation on biodegradability (BOD 5 /COD) of textile and pulp wastewaters were investigated. For all wastewaters studied in this work, the efficiency of treatment based on TOC removal was insignificant even at an absorbed dose of 20 kGy. However, the change of biodegradability was noticeable and largely dependent on the chemical property of wastewaters and the absorbed dose of gamma-rays. For textile wastewaters, gamma-ray treatment increased the biodegradability of desizing effluent due to degradation of polymeric sizing agents such as polyvinyl alcohol. Interestingly, the weight-loss showed the highest value of 0.97 at a relatively low dose of 1 kGy. This may be caused by the degradation of less biodegradable ethylene glycol prior to terephthalic acid decomposition. For pulp wastewater, the gamma-ray treatment did not improve the biodegradability of cooking and bleaching of C/D effluents. However, the biodegradability of bleaching E1 and final effluents was abruptly increased up to 5 kGy then slowly decreased as the absorbed dose was increased. The initial increase of biodegradability may be induced by the decomposition of refractory organic compounds such as chlorophenols, which are known to be the main components of bleaching C/D and final effluents. (author)
Biodegradability of bacterial surfactants.

Science.gov (United States)

Lima, Tânia M S; Procópio, Lorena C; Brandão, Felipe D; Carvalho, André M X; Tótola, Marcos R; Borges, Arnaldo C

2011-06-01

This work aimed at evaluating the biodegradability of different bacterial surfactants in liquid medium and in soil microcosms. The biodegradability of biosurfactants by pure and mixed bacterial cultures was evaluated through CO(2) evolution. Three bacterial strains, Acinetobacter baumanni LBBMA ES11, Acinetobacter haemolyticus LBBMA 53 and Pseudomonas sp. LBBMA 101B, used the biosurfactants produced by Bacillus sp. LBBMA 111A (mixed lipopeptide), Bacillus subtilis LBBMA 155 (lipopeptide), Flavobacterium sp. LBBMA 168 (mixture of flavolipids), Dietzia Maris LBBMA 191(glycolipid) and Arthrobacter oxydans LBBMA 201(lipopeptide) as carbon sources in minimal medium. The synthetic surfactant sodium dodecyl sulfate (SDS) was also mineralized by these microorganisms, but at a lower rate. CO(2) emitted by a mixed bacterial culture in soil microcosms with biosurfactants was higher than in the microcosm containing SDS. Biosurfactant mineralization in soil was confirmed by the increase in surface tension of the soil aqueous extracts after incubation with the mixed bacterial culture. It can be concluded that, in terms of biodegradability and environmental security, these compounds are more suitable for applications in remediation technologies in comparison to synthetic surfactants. However, more information is needed on structure of biosurfactants, their interaction with soil and contaminants and scale up and cost for biosurfactant production.
A novel bio-safe phase separation process for preparing open-pore biodegradable polycaprolactone microparticles.

Science.gov (United States)

Salerno, Aurelio; Domingo, Concepción

2014-09-01

Open-pore biodegradable microparticles are object of considerable interest for biomedical applications, particularly as cell and drug delivery carriers in tissue engineering and health care treatments. Furthermore, the engineering of microparticles with well definite size distribution and pore architecture by bio-safe fabrication routes is crucial to avoid the use of toxic compounds potentially harmful to cells and biological tissues. To achieve this important issue, in the present study a straightforward and bio-safe approach for fabricating porous biodegradable microparticles with controlled morphological and structural features down to the nanometer scale is developed. In particular, ethyl lactate is used as a non-toxic solvent for polycaprolactone particles fabrication via a thermal induced phase separation technique. The used approach allows achieving open-pore particles with mean particle size in the 150-250 μm range and a 3.5-7.9 m(2)/g specific surface area. Finally, the combination of thermal induced phase separation and porogen leaching techniques is employed for the first time to obtain multi-scaled porous microparticles with large external and internal pore sizes and potential improved characteristics for cell culture and tissue engineering. Samples were characterized to assess their thermal properties, morphology and crystalline structure features and textural properties. Copyright © 2014 Elsevier B.V. All rights reserved.
Study on the (biodegradation Process of Bioplastic Materials under Industrial Composting Conditions

Directory of Open Access Journals (Sweden)

Dana Adamcová

2017-01-01

Full Text Available The objective of this study was to determine the biodegradability of bioplastic materials – sponge cloths – available on the European market. They are labeled as 100 % biodegradable but not certified as compostable. The test was carried out in real composting environment. The project duration was 12 weeks. The emphasis was put on discovering whether the sponge cloths are biodegradable or not. Based on the results, it can be concluded that sponge cloths have decomposed completely (sample C and sample D. Samples A have decomposed but exhibited slower degradation rate. Samples B exhibited the higher degradation rate. The main conclusion from this study is that biodegradation of bioplastics materials strongly depends on both, the environment where they are placed and the chemical nature of the material.
Advanced oxidation process-biological system for wastewater containing a recalcitrant pollutant.

Science.gov (United States)

Oller, I; Malato, S; Sánchez-Pérez, J A; Maldonado, M I; Gernjak, W; Pérez-Estrada, L A

2007-01-01

Two advanced oxidation processes (AOPs), ozonation and photo-Fenton, combined with a pilot aerobic biological reactor at field scale were employed for the treatment of industrial non-biodegradable saline wastewater (TOC around 200 mgL(-1)) containing a biorecalcitrant compound, alpha-methylphenylglycine (MPG), at a concentration of 500 mgL(-1). Ozonation experiments were performed in a 50-L reactor with constant inlet ozone of 21.9 g m(-3). Solar photo-Fenton tests were carried out in a 75-L pilot plant made up of four compound parabolic collector (CPC) units. The catalyst concentration employed in this system was 20 mgL(-1) of Fe2+ and the H2O2 concentration was kept in the range of 200-500mgL(-1). Complete degradation of MPG was attained after 1,020 min of ozone treatment, while only 195 min were required for photo-Fenton. Samples from different stages of both AOPs were taken for Zahn-Wellens biocompatibility tests. Biodegradability enhancement of the industrial saline wastewater was confirmed (>70% biodegradability). Biodegradable compounds generated during the preliminary oxidative processes were biologically mineralised in a 170-L aerobic immobilised biomass reactor (IBR). The global efficiency of both AOP/biological combined systems was 90% removal of an initial TOC of over 500 mgL(-1).
Application of hydrodynamic cavitation to improve the biodegradability of mature landfill leachate.

Science.gov (United States)

Bis, M; Montusiewicz, A; Ozonek, J; Pasieczna-Patkowska, S

2015-09-01

In this study, the application of hydrodynamic cavitation to improve the biodegradability of mature landfill leachate was investigated. Three configurations of cavitation device were examined and operational parameters of the process were selected. The study indicated that the orifice plate with a 3/10mm diameter conical concentric hole, characterized by the cavitation number of 0.033, is a reasonable choice to ensure the enhanced biodegradability of mature leachate. Using such a configuration and maintaining 30 recirculation passes through the cavitation zone at inlet pressure of 7 bar, the highest increase of biodegradability index (BI) of approximately 22% occurred, i.e., from the value of 0.046 to 0.056. The FT-IR/PAS analysis confirmed a degradation of refractory compounds that typically prevail in mature leachate. An evaluation of energy efficiency was made in terms of the actual consumed energy measured by using the Kyoritsu KEW6310 Power Quality Tester. A cavitational yield of 9.8 mg COD kJ(-1) was obtained for the optimum configuration and 30 recirculation passes. Regarding energy efficiency, the application of 10 cavitation cycles appeared to be the most profitable. This was due to an almost threefold higher cavitational yield of 27.5 mg COD kJ(-1). However, the preferable option should be selected by considering a satisfactory effect in the biodegradability enhancement. Copyright © 2015 Elsevier B.V. All rights reserved.
Reuse of recalcitrant-rich anaerobic effluent as dilution water after enhancement of biodegradability by Fenton processes.

Science.gov (United States)

Arimi, Milton M; Zhang, Yongjun; Namango, Saul S; Geißen, Sven-Uwe

2016-03-01

Anaerobic digestion is used to treat effluents with a lot of organics, such as molasses distillery wastewater (MDW) which is the effluent of bioethanol production from molasses. The raw MDW requires a lot of dilution water before biodigestion, while the digested MDW has high level of recalcitrants which are problematic for its discharge. This study investigated ferric coagulation, Fenton, Fenton-like (with ferric ions as catalyst) processes and their combinations on the biodegradability of digested MDW. The Fenton and Fenton-like processes after coagulation increased the MDW biodegradability defined by (BOD5/COD) from 0.07 to (0.4-0.6) and saved 50% of H2O2 consumed in the classic Fenton process. The effluent from coagulation coupled to a Fenton-like process was used as dilution water for the raw MDW before the anaerobic digestion. The process was stable with volumetric loading of approx. 2.7 g COD/L/d. It resulted in increased overall biogas recovery and significantly decreased the demand for the dilution water. Copyright © 2015 Elsevier Ltd. All rights reserved.
Determination of biodegradation process of benzene, toluene, ethylbenzene and xylenes in seabed sediment by purge and trap gas chromatography

Energy Technology Data Exchange (ETDEWEB)

Han, Dongqiang [Key Lab. for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua Univ., Beijing (China). Dept. of Physics; China Pharmaceutical Univ., Nanjing (China). Physics Teaching and Research Section, Dept. of Basic Sciences; Ma, Wanyun; Chen, Dieyan [Key Lab. for Atomic and Molecular Nanosciences of Education Ministry, Tsinghua Univ., Beijing (China). Dept. of Physics

2007-12-15

Benzene, toluene, ethylbenzene, and xylenes (BTEX) are commonly found in crude oil and are used in geochemical investigations as direct indicators of the presence of oil and gas. BTEX are easily volatile and can be degraded by microorganisms, which affect their precise measurement seriously. A method for determining the biodegradation process of BTEX in seabed sediment using dynamic headspace (purge and trap) gas chromatography with a photoionization detector (PID) was developed, which had a detection limit of 7.3-13.2 ng L{sup -1} and a recovery rate of 91.6-95.0%. The decrease in the concentration of BTEX components was monitored in seabed sediment samples, which was caused by microorganism biodegradation. The results of BTEX biodegradation process were of great significance in the collection, transportation, preservation, and measurement of seabed sediment samples in the geochemical investigations of oil and gas. (orig.)
Effect of Gamma Irradiation on the Biodegradation Process of some Organic Pollutants

International Nuclear Information System (INIS)

El-Shahawy, M.R.

2014-01-01

Water samples were collected from Ras Gemsa on western coast of Suez Gulf, then microbiologically and chemically analyzed. The total petroleum hydrocarbons (TPH) was at concentration of 357 ppm and exceeded the known permissible limits ranged from 5 to 100 ppm according to the receiving water bulk. On the other hand the biodegrading bacterial counts ( CFU ) clearly reflected the great adaptation of endogenous bacteria to use hydrocarbons as a sole source of carbon. The ratio of biodegrading bacteria to heterotrophic ones was about 3.3%. Five hydrocarbon degrading bacteria were isolated from Suez Gulf Consortia. One isolate HD1 were selected to be promising due to its capacity of hydrocarbon degradation, this promising isolate was characterized and identified by API system as Bacillus subtilis. The biodegradation kinetics of radiated polluted water samples by B. subtilis and the Suez Gulf consortium was monitored gravimetrically. The results showed that The Suez Gulf consortium had more biodegradation capacity than the single isolate B. subtilis overall radiation doses applied and non-radiated polluted water sample. The data showed a significant increase of the biodegradability with increase of radiation doses used
Biodegradability of fuel-ethers in environment; Biodegradabilite des ethers-carburants dans l'environnement

Energy Technology Data Exchange (ETDEWEB)

Fayolle-Guichard, F

2005-04-01

Fuel ethers (methyl tert-butyl ether or MTBE, ethyl tert-butyl ether or ETBE and tert-amyl methyl ether or TAME have been used as gasoline additives since about twenty years in order to meet the requirements for the octane index and to limit the polluting emission in exhaust pipe gas (unburnt hydrocarbons and carbon monoxide). The high water solubility and the poor biodegradability of these compounds make them pollutants frequently encountered in aquifers. The present manuscript summarizes the knowledge concerning the biodegradability of fuel ethers obtained both at IFP and during collaborations with the Pasteur Institute (Paris), the Biotechnology Research Institute (Montreal, Canada) and the Center for Environmental Biotechnology (University of Tennessee, USA). Rhodococcus ruber IFP 2001 and Mycobacterium austroafricanum IFP 2012, two microorganisms isolated at IFP for their ability to grow, respectively, on ETBE and MTBE, were studied in order to determine the intermediates produced during MTBE and ETBE biodegradation and the enzymes required for each biodegradation step, thus allowing us to propose MTBE and ETBE catabolic pathways. A proteomic approach, from the protein induced during the degradation of ETBE or MTBE to the genes encoding these different enzymes, was carried out. The isolation of such genes is required:1) to use them for help in determining the bio-remediation capacities in polluted aquifers (DNA micro-arrays), 2) to monitor the microorganisms isolated for their degradative capacities during bio-remediation processes (fluorescent in situ hybridization or FISH) and 3) to create new tools for the detection and the quantification of ETBE or MTBE in contaminated aquifers (bio-sensor). The manuscript also describes the different ways for the adaptation of microorganisms to the presence of a xenobiotic compound. (author)
FINASOL OSR 52 active components biodegradation by using the biologic activator Biolen IG 30

Energy Technology Data Exchange (ETDEWEB)

Bergueiro, J. R.; Luengo, M. C.; Socias, S.; Perez, F.; Laseca, D. [Universidad de las Islas Baleares, Palma de Mallorca (Spain); Perez-Navarro, A.; Morales, N. [Universidad Alfonso X El Sabio, Madrid (Spain)

1997-10-01

Degradation of the active ingredients in the FINASOL OSR 52, a commonly used dispersant in the treatment of marine oil spills, was studied. BIOLEN IG 30, comprising a mixture of bacteria, specially selected for their ability to degrade a wide range of chemical compounds, was used as the biodegrading agent. The kinetic coefficients of the degradation process were determined at different conditions, at ambient temperature, and at controlled 20 degrees C. BIOLEN IC 10 biologic activator was found to be adequate for total ionic and anionic dispersant degradation of the FINASOL OSR 52 at room temperature and at controlled 20 degrees C. Weekly addition of one gram of BIOLEN IG 30 was observed to improve biodegradation percentages for both ionic and anionic dispersants at controlled 20 degrees C. 12 refs., 5 tabs., 4 figs.
FINASOL OSR 52 active components biodegradation by using the biologic activator Biolen IG 30

International Nuclear Information System (INIS)

Bergueiro, J. R.; Luengo, M. C.; Socias, S.; Perez, F.; Laseca, D.; Perez-Navarro, A.; Morales, N.

1997-01-01

Degradation of the active ingredients in the FINASOL OSR 52, a commonly used dispersant in the treatment of marine oil spills, was studied. BIOLEN IG 30, comprising a mixture of bacteria, specially selected for their ability to degrade a wide range of chemical compounds, was used as the biodegrading agent. The kinetic coefficients of the degradation process were determined at different conditions, at ambient temperature, and at controlled 20 degrees C. BIOLEN IC 10 biologic activator was found to be adequate for total ionic and anionic dispersant degradation of the FINASOL OSR 52 at room temperature and at controlled 20 degrees C. Weekly addition of one gram of BIOLEN IG 30 was observed to improve biodegradation percentages for both ionic and anionic dispersants at controlled 20 degrees C. 12 refs., 5 tabs., 4 figs
In situ stimulation vs. bioaugmentation: Can microbial inoculation of plant roots enhance biodegradation of organic compounds?

Energy Technology Data Exchange (ETDEWEB)

Kingsley, M.T.; Metting, F.B. Jr.; Fredrickson, J.K. [Pacific Northwest Lab., Richland, WA (United States); Seidler, R.J. [Environmental Protection Agency, Corvallis, OR (United States). Environmental Research Lab.

1993-06-01

The use of plant roots and their associated rhizosphere bacteria for biocontainment and biorestoration offers several advantages for treating soil-dispersed contaminants and for application to large land areas. Plant roots function as effective delivery systems, since root growth transports bacteria vertically and laterally along the root in the soil column (see [ 1,2]). Movement of microbes along roots and downward in the soil column can be enhanced via irrigation [1-4]. For example, Ciafardini et al. [3] increased the nodulation and the final yield of soybeans during pod filling by including Bradyrhizobium japonicum in the irrigation water. Using rhizosphere microorganisms is advantageous for biodegradation of compounds that are degraded mainly by cometabolic processes, e.g., trichloroethylene (TCE). The energy source for bacterial growth and metabolism is supplied by the plant in the form of root exudates and other sloughed organic material. Plants are inexpensive, and by careful choice of species that possess either tap or fibrous root growth patterns, they can be used to influence mass transport of soil contaminants to the root surface via the transpiration stream [5]. Cropping of plants to remove heavy metals from contaminated soils has been proposed as a viable, low-cost, low-input treatment option [6]. The interest in use of plants as a remediation strategy has even reached the popular press [7], where the use of ragweed for the reclamation of sites contaminated with tetraethyl lead and other heavy metals was discussed.
In silico models for predicting ready biodegradability under REACH: a comparative study.

Science.gov (United States)

Pizzo, Fabiola; Lombardo, Anna; Manganaro, Alberto; Benfenati, Emilio

2013-10-01

REACH (Registration Evaluation Authorization and restriction of Chemicals) legislation is a new European law which aims to raise the human protection level and environmental health. Under REACH all chemicals manufactured or imported for more than one ton per year must be evaluated for their ready biodegradability. Ready biodegradability is also used as a screening test for persistent, bioaccumulative and toxic (PBT) substances. REACH encourages the use of non-testing methods such as QSAR (quantitative structure-activity relationship) models in order to save money and time and to reduce the number of animals used for scientific purposes. Some QSAR models are available for predicting ready biodegradability. We used a dataset of 722 compounds to test four models: VEGA, TOPKAT, BIOWIN 5 and 6 and START and compared their performance on the basis of the following parameters: accuracy, sensitivity, specificity and Matthew's correlation coefficient (MCC). Performance was analyzed from different points of view. The first calculation was done on the whole dataset and VEGA and TOPKAT gave the best accuracy (88% and 87% respectively). Then we considered the compounds inside and outside the training set: BIOWIN 6 and 5 gave the best results for accuracy (81%) outside training set. Another analysis examined the applicability domain (AD). VEGA had the highest value for compounds inside the AD for all the parameters taken into account. Finally, compounds outside the training set and in the AD of the models were considered to assess predictive ability. VEGA gave the best accuracy results (99%) for this group of chemicals. Generally, START model gave poor results. Since BIOWIN, TOPKAT and VEGA models performed well, they may be used to predict ready biodegradability. Copyright © 2013 Elsevier B.V. All rights reserved.
Biodegradation of phenol by a newly isolated marine bacterial strain ...

African Journals Online (AJOL)

ajl yemi

2011-12-26

Dec 26, 2011 ... Full Length Research Paper. Biodegradation of phenol ... screen bacteria with potential for phenol degradation from sea water, mud and sand. .... poisonous compound media, such as phenol (Santos et al., 2001). For instance ...
Bioaccessible Porosity in Soil Aggregates and Implications for Biodegradation of High Molecular Weight Petroleum Compounds.

Science.gov (United States)

Akbari, Ali; Ghoshal, Subhasis

2015-12-15

We evaluated the role of soil aggregate pore size on biodegradation of essentially insoluble petroleum hydrocarbons that are biodegraded primarily at the oil-water interface. The size and spatial distribution of pores in aggregates sampled from biodegradation experiments of a clayey, aggregated, hydrocarbon-contaminated soil with relatively high bioremediation end point were characterized by image analyses of X-ray micro-CT scans and N2 adsorption. To determine the bioaccessible pore sizes, we performed separate experiments to assess the ability of hydrocarbon degrading bacteria isolated from the soil to pass through membranes with specific sized pores and to access hexadecane (model insoluble hydrocarbon). Hexadecane biodegradation occurred only when pores were 5 μm or larger, and did not occur when pores were 3 μm and smaller. In clayey aggregates, ∼ 25% of the aggregate volume was attributed to pores larger than 4 μm, which was comparable to that in aggregates from a sandy, hydrocarbon-contaminated soil (~23%) scanned for comparison. The ratio of volumes of inaccessible pores (4 μm) in the clayey aggregates was 0.32, whereas in the sandy aggregates it was approximately 10 times lower. The role of soil microstructure on attainable bioremediation end points could be qualitatively assessed in various soils by the aggregate characterization approach outlined herein.

Biodegradation of sulfamethoxazole photo-transformation products in a water/sediment test.

Science.gov (United States)

Su, Tong; Deng, Huiping; Benskin, Jonathan P; Radke, Michael

2016-04-01

Occurrence of the antibiotic sulfamethoxazole (SMX) in the aquatic environment is of concern due to its potential to induce antibiotic resistance in pathogenic bacteria. While degradation of SMX can occur by numerous processes, the environmental fate of its transformation products (TPs) remains poorly understood. In the present work, biodegradation of SMX photo-TPs was investigated in a water/sediment system. Photo-TPs were produced by exposing SMX to artificial sunlight for 48 h. The resulting mixture of 8 photo-TPs was characterized using a combination of ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry and tandem mass spectrometry, and then used in biodegradation experiments. Significant differences in transformation among SMX photo-TPs were observed in the water/sediment system, with four photo-TPs displaying evidence of biodegradation (dissipation half-lives [DT50] of 39.7 d for 3-amino-5-methylisoxazole, 12.7 d for 4-nitro-sulfamethxoazole, 7.6 d for an SMX isomer and 2.4 d for [C10H13N3O4S]), two displaying primarily abiotic degradation (DT50 of 31 d for sulfanilic acid and 74.9 d for 5-methylisoxazol-3-yl-sulfamate), and two photo-TPs behaving largely recalcitrantly. Remarkably, TPs previously reported to be photo-stable also were persistent in biodegradation experiments. The most surprising observation was an increase in SMX concentrations when the irradiated solution was incubated, which we attribute to back-transformation of certain photo-TPs by sediment bacteria (85% from 4-nitro-sulfamethoxazole). This process could contribute to exposure to SMX in the aquatic environment that is higher than one would expect based on the fate of SMX alone. The results highlight the importance of considering TPs along with their parent compounds when characterizing environmental risks of emerging contaminants. Copyright © 2016 Elsevier Ltd. All rights reserved.
Biodegradation of clofibric acid and identification of its metabolites.

Science.gov (United States)

Salgado, R; Oehmen, A; Carvalho, G; Noronha, J P; Reis, M A M

2012-11-30

Clofibric acid (CLF) is the pharmaceutically active metabolite of lipid regulators clofibrate, etofibrate and etofyllinclofibrate, and it is considered both environmentally persistent and refractory. This work studied the biotransformation of CLF in aerobic sequencing batch reactors (SBRs) with mixed microbial cultures, monitoring the efficiency of biotransformation of CLF and the production of metabolites. The maximum removal achieved was 51% biodegradation (initial CLF concentration=2 mg L(-1)), where adsorption and abiotic removal mechanisms were shown to be negligible, showing that CLF is indeed biodegradable. Tests showed that the observed CLF biodegradation was mainly carried out by heterotrophic bacteria. Three main metabolites were identified, including α-hydroxyisobutyric acid, lactic acid and 4-chlorophenol. The latter is known to exhibit higher toxicity than the parent compound, but it did not accumulate in the SBRs. α-Hydroxyisobutyric acid and lactic acid accumulated for a period, where nitrite accumulation may have been responsible for inhibiting their degradation. A metabolic pathway for the biodegradation of CLF is proposed in this study. Copyright © 2012 Elsevier B.V. All rights reserved.
Biodegradation of oil refinery wastes under OPA and CERCLA

International Nuclear Information System (INIS)

Banipal, B.S.; Myers, J.M.; Fisher, C.W.

1995-01-01

Land treatment of oil refinery wastes has been used as a disposal method for decades. More recently, numerous laboratory studies have been performed attempting to quantify degradation rates of more toxic polycyclic aromatic hydrocarbon compounds (PAHs). This paper discusses the results of the full-scale aerobic biodegradation operations using land treatment at the Macmillan Ring-Free Oil refining facility. The tiered feasibility approach in the evaluation of using biodegradation as a treatment method to achieve site-specific clean-up including pilot scale biodegradation operations is included in an earlier paper. Analytical results of biodegradation indicate that degradation rates observed in the laboratory can be met and exceeded under field conditions and that the site-specific cleanup criteria can be attained within a proposed project time. Also presented are degradation rates and half-lives for PAHs for which cleanup criteria has been established. PAH degradation rates and half-life values are determined and compared with the laboratory degradation rates and half-life values which used similar oil refinery wastes by other investigators (API 1987)
Biodegradation of oil refinery wastes under OPA and CERCLA

Energy Technology Data Exchange (ETDEWEB)

Gamblin, W.W.; Banipal, B.S.; Myers, J.M. [Ecology and Environment, Inc., Dallas, TX (United States)] [and others

1995-12-31

Land treatment of oil refinery wastes has been used as a disposal method for decades. More recently, numerous laboratory studies have been performed attempting to quantify degradation rates of more toxic polycyclic aromatic hydrocarbon compounds (PAHs). This paper discusses the results of the fullscale aerobic biodegradation operations using land treatment at the Macmillan Ring-Free Oil refining facility. The tiered feasibility approach of evaluating biodegradation as a treatment method to achieve site-specific cleanup criteria, including pilot biodegradation operations, is discussed in an earlier paper. Analytical results of biodegradation indicate that degradation rates observed in the laboratory can be met and exceeded under field conditions and that site-specific cleanup criteria can be attained within a proposed project time. Also prevented are degradation rates and half-lives for PAHs for which cleanup criteria have been established. PAH degradation rates and half-life values are determined and compared with the laboratory degradation rates and half-life values which used similar oil refinery wastes by other in investigators (API 1987).
Biodegradability of fuel-ethers in environment; Biodegradabilite des ethers-carburants dans l'environnement

Energy Technology Data Exchange (ETDEWEB)

Fayolle-Guichard, F.

2005-04-01

Fuel ethers (methyl tert-butyl ether or MTBE, ethyl tert-butyl ether or ETBE and tert-amyl methyl ether or TAME have been used as gasoline additives since about twenty years in order to meet the requirements for the octane index and to limit the polluting emission in exhaust pipe gas (unburnt hydrocarbons and carbon monoxide). The high water solubility and the poor biodegradability of these compounds make them pollutants frequently encountered in aquifers. The present manuscript summarizes the knowledge concerning the biodegradability of fuel ethers obtained both at IFP and during collaborations with the Pasteur Institute (Paris), the Biotechnology Research Institute (Montreal, Canada) and the Center for Environmental Biotechnology (University of Tennessee, USA). Rhodococcus ruber IFP 2001 and Mycobacterium austroafricanum IFP 2012, two microorganisms isolated at IFP for their ability to grow, respectively, on ETBE and MTBE, were studied in order to determine the intermediates produced during MTBE and ETBE biodegradation and the enzymes required for each biodegradation step, thus allowing us to propose MTBE and ETBE catabolic pathways. A proteomic approach, from the protein induced during the degradation of ETBE or MTBE to the genes encoding these different enzymes, was carried out. The isolation of such genes is required:1) to use them for help in determining the bio-remediation capacities in polluted aquifers (DNA micro-arrays), 2) to monitor the microorganisms isolated for their degradative capacities during bio-remediation processes (fluorescent in situ hybridization or FISH) and 3) to create new tools for the detection and the quantification of ETBE or MTBE in contaminated aquifers (bio-sensor). The manuscript also describes the different ways for the adaptation of microorganisms to the presence of a xenobiotic compound. (author)
Biodegradation of NSO-compounds under different redox-conditions

DEFF Research Database (Denmark)

Dyreborg, S.; Arvin, E.; Broholm, K.

1997-01-01

Laboratory experiments were carried out to investigate the potential of groundwater microorganisms to degrade selected heterocyclic aromatic compounds containing nitrogen, sulphur, or oxygen (NSO-compounds) under four redox-conditions over a period of 846 days. Eight compounds (pyrrole, 1...... anaerobic conditions, even though the microorganisms present in the anaerobic microcosms were active throughout the incubation period. A high variability in the lag period among the NSO-compounds was observed under aerobic conditions. While quinoline, indole, and carbazole were degraded with a lag period...
Additional Equipment for Soil Biodegradation

Science.gov (United States)

Vondráčková, Terezie; Kraus, Michal; Šál, Jiří

2017-12-01

Intensification of industrial production, increasing citizens’ living standards, expanding the consumer assortment mean in the production - consumption cycle a constantly increasing occurrence of waste material, which by its very nature must be considered as a source of useful raw materials in all branches of human activity. In addition to strict legislative requirements, a number of circumstances characterize waste management. It is mainly extensive transport associated with the handling and storage of large volumes of substances with a large assortment of materials (substances of all possible physical and chemical properties) and high demands on reliability and time coordination of follow-up processes. Considerable differences in transport distances, a large number of sources, processors and customers, and not least seasonal fluctuations in waste and strong price pressures cannot be overlooked. This highlights the importance of logistics in waste management. Soils that are contaminated with oil and petroleum products are hazardous industrial waste. Methods of industrial waste disposal are landfilling, biological processes, thermal processes and physical and chemical methods. The paper focuses on the possibilities of degradation of oil pollution, in particular biodegradation by bacteria, which is relatively low-cost among technologies. It is necessary to win the fight with time so that no ground water is contaminated. We have developed two additional devices to help reduce oil accident of smaller ranges. In the case of such an oil accident, it is necessary to carry out the permeability test of contaminated soil in time and, on this basis, to choose the technology appropriate to the accident - either in-sit biodegradation - at the site of the accident, or on-sit - to remove the soil and biodegrade it on the designated deposits. A special injection drill was developed for in-sit biodegradation, tossing and aeration equipment of the extracted soil was developed for
A sacrificial process for fabrication of biodegradable polymer membranes with submicron thickness.

Science.gov (United States)

Beardslee, Luke A; Stolwijk, Judith; Khaladj, Dimitrius A; Trebak, Mohamed; Halman, Justin; Torrejon, Karen Y; Niamsiri, Nuttawee; Bergkvist, Magnus

2016-08-01

A new sacrificial molding process using a single mask has been developed to fabricate ultrathin 2-dimensional membranes from several biocompatible polymeric materials. The fabrication process is similar to a sacrificial microelectromechanical systems (MEMS) process flow, where a mold is created from a material that can be coated with a biodegradable polymer and subsequently etched away, leaving behind a very thin polymer membrane. In this work, two different sacrificial mold materials, silicon dioxide (SiO2 ) and Liftoff Resist (LOR) were used. Three different biodegradable materials; polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and polyglycidyl methacrylate (PGMA), were chosen as model polymers. We demonstrate that this process is capable of fabricating 200-500 nm thin, through-hole polymer membranes with various geometries, pore-sizes and spatial features approaching 2.5 µm using a mold fabricated via a single contact photolithography exposure. In addition, the membranes can be mounted to support rings made from either SU8 or PCL for easy handling after release. Cell culture compatibility of the fabricated membranes was evaluated with human dermal microvascular endothelial cells (HDMECs) seeded onto the ultrathin porous membranes, where the cells grew and formed confluent layers with well-established cell-cell contacts. Furthermore, human trabecular meshwork cells (HTMCs) cultured on these scaffolds showed similar proliferation as on flat PCL substrates, further validating its compatibility. All together, these results demonstrated the feasibility of our sacrificial fabrication process to produce biocompatible, ultra-thin membranes with defined microstructures (i.e., pores) with the potential to be used as substrates for tissue engineering applications. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1192-1201, 2016. © 2015 Wiley Periodicals, Inc.
Acetate biodegradation by anaerobic microorganisms at high pH and high calcium concentration

International Nuclear Information System (INIS)

Yoshida, Takahiro

2011-01-01

Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic 14 C compounds in cementitious repositories. Tamagawa river sediment or Teganuma pond sediment was anaerobically cultured with 5 mM acetate and 10 mM nitrate at pH 9.5-12 at 30 o C. After 20 and 90 days, the acetate concentration of the culture medium was analyzed and found to have decreased below 5 mM at pH ≤ 11. On the other hand, it did not decrease when either sediment was incubated in the absence of nitrate. These results suggest that nitrate-reducing bacteria can biodegrade acetate under more alkaline conditions than the reported pH range in which nitrate-reducing bacteria can exhibit activity. Acetate biodegradation was also examined at a high calcium concentration. Sediments were anaerobically cultured at pH 9.5 with 5 mM acetate and 10 mM nitrate in solution, equilibrated with ordinary Portland cement hydrate, in which the Ca concentration was 14.6 mM. No decrease in acetate concentration after incubation of the sediments was observed, nor was it lower than in the absence of cementitious composition, suggesting that kinetics of acetate biodegradation by anaerobic microorganisms is lowered by a high Ca concentration. - Research highlights: → Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic 14 C compounds in cementitious repositories. → Nitrate-reducing bacteria can biodegrade acetate at pH ≤ 11. → Kinetics of acetate biodegradation by anaerobic microorganisms might be lowered by a high Ca concentration.
Biodegradation of polyether algal toxins–Isolation of potential marine bacteria

Science.gov (United States)

SHETTY, KATEEL G.; HUNTZICKER, JACQUELINE V.; REIN, KATHLEEN S.; JAYACHANDRAN, KRISH

2012-01-01

Marine algal toxins such as brevetoxins, okadaic acid, yessotoxin, and ciguatoxin are polyether compounds. The fate of polyether toxins in the aqueous phase, particularly bacterial biotransformation of the toxins, is poorly understood. An inexpensive and easily available polyether structural analog salinomycin was used for enrichment and isolation of potential polyether toxin degrading aquatic marine bacteria from Florida bay area, and from red tide endemic sites in the South Florida Gulf coast. Bacterial growth on salinomycin was observed in most of the enrichment cultures from both regions with colony forming units ranging from 0 to 6 × 107 per mL. The salinomycin biodegradation efficiency of bacterial isolates determined using LC-MS ranged from 22% to 94%. Selected bacterial isolates were grown in media with brevetoxin as the sole carbon source to screen for brevetoxin biodegradation capability using ELISA. Out of the two efficient salinomycin biodegrading isolates MB-2 and MB-4, maximum brevetoxin biodegradation efficiency of 45% was observed with MB-4, while MB-2 was unable to biodegrade brevetoxin. Based on 16S rRNA sequence similarity MB-4 was found have a match with Chromohalobacter sp. PMID:20954040
Biodegradation of polyether algal toxins--isolation of potential marine bacteria.

Science.gov (United States)

Shetty, Kateel G; Huntzicker, Jacqueline V; Rein, Kathleen S; Jayachandran, Krish

2010-12-01

Marine algal toxins such as brevetoxins, okadaic acid, yessotoxin, and ciguatoxin are polyether compounds. The fate of polyether toxins in the aqueous phase, particularly bacterial biotransformation of the toxins, is poorly understood. An inexpensive and easily available polyether structural analog salinomycin was used for enrichment and isolation of potential polyether toxin degrading aquatic marine bacteria from Florida bay area, and from red tide endemic sites in the South Florida Gulf coast. Bacterial growth on salinomycin was observed in most of the enrichment cultures from both regions with colony forming units ranging from 0 to 6×10(7) per mL. The salinomycin biodegradation efficiency of bacterial isolates determined using LC-MS ranged from 22% to 94%. Selected bacterial isolates were grown in media with brevetoxin as the sole carbon source to screen for brevetoxin biodegradation capability using ELISA. Out of the two efficient salinomycin biodegrading isolates MB-2 and MB-4, maximum brevetoxin biodegradation efficiency of 45% was observed with MB-4, while MB-2 was unable to biodegrade brevetoxin. Based on 16S rRNA sequence similarity MB-4 was found have a match with Chromohalobacter sp.
The effect of mechanical loads on the degradation of aliphatic biodegradable polyesters.

Science.gov (United States)

Li, Ying; Chu, Zhaowei; Li, Xiaoming; Ding, Xili; Guo, Meng; Zhao, Haoran; Yao, Jie; Wang, Lizhen; Cai, Qiang; Fan, Yubo

2017-06-01

Aliphatic biodegradable polyesters have been the most widely used synthetic polymers for developing biodegradable devices as alternatives for the currently used permanent medical devices. The performances during biodegradation process play crucial roles for final realization of their functions. Because physiological and biochemical environment in vivo significantly affects biodegradation process, large numbers of studies on effects of mechanical loads on the degradation of aliphatic biodegradable polyesters have been launched during last decades. In this review article, we discussed the mechanism of biodegradation and several different mechanical loads that have been reported to affect the biodegradation process. Other physiological and biochemical factors related to mechanical loads were also discussed. The mechanical load could change the conformational strain energy and morphology to weaken the stability of the polymer. Besides, the load and pattern could accelerate the loss of intrinsic mechanical properties of polymers. This indicated that investigations into effects of mechanical loads on the degradation should be indispensable. More combination condition of mechanical loads and multiple factors should be considered in order to keep the degradation rate controllable and evaluate the degradation process in vivo accurately. Only then can the degradable devise achieve the desired effects and further expand the special applications of aliphatic biodegradable polyesters.
Molecular processes in the biodegradation of crude oils and crude oil products in the natural reservoir and in laboratory experiments

International Nuclear Information System (INIS)

Schalenbach, S.S.

1993-10-01

Two ains were pursued in the present study; first, to find positive indicators of the onset of biodegradation of reservoir oil wherever other parameters fail to give a clear picture; second, to establish a basic understanding of the molecular processes underlying the biodegradation of hydrocarbons and thus create a starting point for finding better criteria for valuating biological restoration methods for crude oil contaminated soils. (orig./HS) [de
Biodegradation performance of environmentally-friendly insulating oil

Science.gov (United States)

Yang, Jun; He, Yan; Cai, Shengwei; Chen, Cheng; Wen, Gang; Wang, Feipeng; Fan, Fan; Wan, Chunxiang; Wu, Liya; Liu, Ruitong

2018-02-01

In this paper, biodegradation performance of rapeseed insulating oil (RDB) and FR3 insulating oil (FR3) was studied by means of ready biodegradation method which was performed with Organization for Economic Co-operation and Development (OECD) 301B. For comparison, the biodegradation behaviour of 25# mineral insulating oil was also characterized with the same method. The testing results shown that the biodegradation degree of rapeseed insulating oil, FR3 insulating oil and 25# mineral insulating oil was 95.8%, 98.9% and 38.4% respectively. Following the “new chemical risk assessment guidelines” (HJ/T 154 - 2004), which illustrates the methods used to identify and assess the process safety hazards inherent. The guidelines can draw that the two vegetable insulating oils, i.e. rapeseed insulating oil and FR3 insulating oil are easily biodegradable. Therefore, the both can be classified as environmentally-friendly insulating oil. As expected, 25# mineral insulating oil is hardly biodegradable. The main reason is that 25# mineral insulating oil consists of isoalkanes, cyclanes and a few arenes, which has few unsaturated bonds. Biodegradation of rapeseed insulating oil and FR3 insulating oil also remain some difference. Biodegradation mechanism of vegetable insulating oil was revealed from the perspective of hydrolysis kinetics.
Bacterial Degradation of Aromatic Compounds

Directory of Open Access Journals (Sweden)

Qing X. Li

2009-01-01

Full Text Available Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.
Electrospun biodegradable polymers loaded with bactericide agents

Directory of Open Access Journals (Sweden)

Ramaz Katsarava

2016-03-01

Full Text Available Development of materials with an antimicrobial activity is fundamental for different sectors, including medicine and health care, water and air treatment, and food packaging. Electrospinning is a versatile and economic technique that allows the incorporation of different natural, industrial, and clinical agents into a wide variety of polymers and blends in the form of micro/nanofibers. Furthermore, the technique is versatile since different constructs (e.g. those derived from single electrospinning, co-electrospinning, coaxial electrospinning, and miniemulsion electrospinning can be obtained to influence the ability to load agents with different characteristics and stability and to modify the release behaviour. Furthermore, antimicrobial agents can be loaded during the electrospinning process or by a subsequent coating process. In order to the mitigate burst release effect, it is possible to encapsulate the selected drug into inorganic nanotubes and nanoparticles, as well as in organic cyclodextrine polysaccharides. In the same way, processes that involve covalent linkage of bactericide agents during surface treatment of electrospun samples may also be considered. The present review is focused on more recent works concerning the electrospinning of antimicrobial polymers. These include chitosan and common biodegradable polymers with activity caused by the specific load of agents such as metal and metal oxide particles, quaternary ammonium compounds, hydantoin compounds, antibiotics, common organic bactericides, and bacteriophages.
Biodegradability and biodegradation rate of poly(caprolactone)-starch blend and poly(butylene succinate) biodegradable polymer under aerobic and anaerobic environment.

Science.gov (United States)

Cho, H S; Moon, H S; Kim, M; Nam, K; Kim, J Y

2011-03-01

The biodegradability and the biodegradation rate of two kinds biodegradable polymers; poly(caprolactone) (PCL)-starch blend and poly(butylene succinate) (PBS), were investigated under both aerobic and anaerobic conditions. PCL-starch blend was easily degraded, with 88% biodegradability in 44 days under aerobic conditions, and showed a biodegradation rate of 0.07 day(-1), whereas the biodegradability of PBS was only 31% in 80 days under the same conditions, with a biodegradation rate of 0.01 day(-1). Anaerobic bacteria degraded well PCL-starch blend (i.e., 83% biodegradability for 139 days); however, its biodegradation rate was relatively slow (6.1 mL CH(4)/g-VS day) compared to that of cellulose (13.5 mL CH(4)/g-VS day), which was used as a reference material. The PBS was barely degraded under anaerobic conditions, with only 2% biodegradability in 100 days. These results were consistent with the visual changes and FE-SEM images of the two biodegradable polymers after the landfill burial test, showing that only PCL-starch blend had various sized pinholes on the surface due to attack by microorganisms. This result may be use in deciding suitable final disposal approaches of different types of biodegradable polymers in the future. Copyright © 2010 Elsevier Ltd. All rights reserved.
Synthesis, spectral characterization thermal stability, antimicrobial studies and biodegradation of starch–thiourea based biodegradable polymeric ligand and its coordination complexes with [Mn(II, Co(II, Ni(II, Cu(II, and Zn(II] metals

Directory of Open Access Journals (Sweden)

Nahid Nishat

2016-09-01

Full Text Available A biodegradable polymer was synthesized by the modification reaction of polymeric starch with thiourea which is further modified by transition metals, Mn(II, Co(II, Ni(II, Cu(II and Zn(II. All the polymeric compounds were characterized by (FT-IR spectroscopy, 1H NMR spectroscopy, 13C NMR spectroscopy, UV–visible spectra, magnetic moment measurements, thermogravimetric analysis (TGA and antibacterial activities. Polymer complexes of Mn(II, Co(II and Ni(II show octahedral geometry, while polymer complexes of Cu(II and Zn(II show square planar and tetrahedral geometry, respectively. The TGA revealed that all the polymer metal complexes are more thermally stable than their parental ligand. In addition, biodegradable studies of all the polymeric compounds were also carried out through ASTM-D-5338-93 standards of biodegradable polymers by CO2 evolution method which says that coordination decreases biodegradability. The antibacterial activity was screened with the agar well diffusion method against some selected microorganisms. Among all the complexes, the antibacterial activity of the Cu(II polymer–metal complex showed the highest zone of inhibition because of its higher stability constant.
A new biodegradation prediction model specific to petroleum hydrocarbons.

Science.gov (United States)

Howard, Philip; Meylan, William; Aronson, Dallas; Stiteler, William; Tunkel, Jay; Comber, Michael; Parkerton, Thomas F

2005-08-01

A new predictive model for determining quantitative primary biodegradation half-lives of individual petroleum hydrocarbons has been developed. This model uses a fragment-based approach similar to that of several other biodegradation models, such as those within the Biodegradation Probability Program (BIOWIN) estimation program. In the present study, a half-life in days is estimated using multiple linear regression against counts of 31 distinct molecular fragments. The model was developed using a data set consisting of 175 compounds with environmentally relevant experimental data that was divided into training and validation sets. The original fragments from the Ministry of International Trade and Industry BIOWIN model were used initially as structural descriptors and additional fragments were then added to better describe the ring systems found in petroleum hydrocarbons and to adjust for nonlinearity within the experimental data. The training and validation sets had r2 values of 0.91 and 0.81, respectively.
Microneedles array with biodegradable tips for transdermal drug delivery

Science.gov (United States)

Iliescu, Ciprian; Chen, Bangtao; Wei, Jiashen; Tay, Francis E. H.

2008-12-01

The paper presented an enhancement solution for transdermal drug delivery using microneedles array with biodegradable tips. The microneedles array was fabricated by using deep reactive ion etching (DRIE) and the biodegradable tips were made to be porous by electrochemical etching process. The porous silicon microneedle tips can greatly enhance the transdermal drug delivery in a minimum invasion, painless, and convenient manner, at the same time; they are breakable and biodegradable. Basically, the main problem of the silicon microneedles consists of broken microneedles tips during the insertion. The solution proposed is to fabricate the microneedle tip from a biodegradable material - porous silicon. The silicon microneedles are fabricated using DRIE notching effect of reflected charges on mask. The process overcomes the difficulty in the undercut control of the tips during the classical isotropic silicon etching process. When the silicon tips were formed, the porous tips were then generated using a classical electrochemical anodization process in MeCN/HF/H2O solution. The paper presents the experimental results of in vitro release of calcein and BSA with animal skins using a microneedle array with biodegradable tips. Compared to the transdermal drug delivery without any enhancer, the microneedle array had presented significant enhancement of drug release.

Heat treatment of organics for increasing anaerobic biodegradability. Quarterly progress report, July 1, 1979-September 30, 1979

Energy Technology Data Exchange (ETDEWEB)

Stuckey, D.; Colberg, P.J.; Baugh, K.; Young, L.Y.; McCarty, P.L.

1979-01-01

The objective of this study is to evaluate thermochemical pretreatment as a method for increasing the anaerobic biodegradability of organic materials so that they can be more completely fermented to methane gas, a potential source of fuel. The current study has four specific phases: (1) biological conversion of lignocellulose to methane, (2) biodegradation of lignin and lignin fractions, (3) pretreatment of nitrogenous organics for increasing biodegradability, (4) biodegradation of lignin aromatic compounds, and (5) biochemical methane potential and toxicity testing. Results are reported for phases one, two, and three. No new information is available for phases four and five at this time.
Biodegradation of oils in uranium deposits

International Nuclear Information System (INIS)

Landais, P.

1989-01-01

The biodegradation of free hydrocarbons that have migrated in reservoir facies has often been observed in the field of petroleum exploration. This alteration is characterized by the progressive removal by bacteria of the different types of hydrocarbons: n-alkanes, branched alkanes, aromatics, cycloalkanes, etc. One of the most important consequences of biodegradation is the biogenic reduction of sulphate, which has been noticed in several Pb-Zn deposits. Biodegradation of oils spatially associated with uranium mineralizations has been observed in Temple Mountain, Utah, and the Grand Canyon, Arizona, in the United States of America, and in Lodeve in France. It leads to the transformation of fluid oils into solid bitumens. Emphasis is placed on the relationships between the effects of biodegradation on organic matter (oxidation of aromatization) and the nature of aqueous fluids analysed in fluid inclusions trapped in authigenic minerals. Different mechanisms are proposed to explain the transformations of organic matter during biodegradation and their possible links with the ore forming process. (author). 40 refs, 13 figs, 1 tab
Monitoring biodegradation of ethene and bioremediation of chlorinated ethenes at a contaminated site using compound-specific isotope analysis (CSIA).

Science.gov (United States)

Mundle, Scott O C; Johnson, Tiffany; Lacrampe-Couloume, Georges; Pérez-de-Mora, Alfredo; Duhamel, Melanie; Edwards, Elizabeth A; McMaster, Michaye L; Cox, Evan; Révész, Kinga; Sherwood Lollar, Barbara

2012-02-07

Chlorinated ethenes are commonly found in contaminated groundwater. Remediation strategies focus on transformation processes that will ultimately lead to nontoxic products. A major concern with these strategies is the possibility of incomplete dechlorination and accumulation of toxic daughter products (cis-1,2-dichloroethene (cDCE), vinyl chloride (VC)). Ethene mass balance can be used as a direct indicator to assess the effectiveness of dechlorination. However, the microbial processes that affect ethene are not well characterized and poor mass balance may reflect biotransformation of ethene rather than incomplete dechlorination. Microbial degradation of ethene is commonly observed in aerobic systems but fewer cases have been reported in anaerobic systems. Limited information is available on the isotope enrichment factors associated with these processes. Using compound-specific isotope analysis (CSIA) we determined the enrichment factors associated with microbial degradation of ethene in anaerobic microcosms (ε = -6.7‰ ± 0.4‰, and -4.0‰ ± 0.8‰) from cultures collected from the Twin Lakes wetland area at the Savannah River site in Georgia (United States), and in aerobic microcosms (ε = -3.0‰ ± 0.3‰) from Mycobacterium sp. strain JS60. Under anaerobic and aerobic conditions, CSIA can be used to determine whether biotransformation of ethene is occurring in addition to biodegradation of the chlorinated ethenes. Using δ(13)C values determined for ethene and for chlorinated ethenes at a contaminated field site undergoing bioremediation, this study demonstrates how CSIA of ethene can be used to reduce uncertainty and risk at a site by distinguishing between actual mass balance deficits during reductive dechlorination and apparent lack of mass balance that is related to biotransformation of ethene.
Bioestimulation process during the biodegradation of TPH in oil contaminated soil

Directory of Open Access Journals (Sweden)

Victoria Vallejo

2005-07-01

Full Text Available The present study evaluated the effect of the nutrients addition (N and P by using the amendment of inorganic simple fertilizer (SIS and inorganic compound fertilizers (FIC in the biodegradation of total hydrocarbon petroleum (TPH. Mesocosmos were used with contaminated soil (20,000 mgTPH/kgdw, abiotic control and a control without nutrient (n=3 were used to evaluate the effect of nutrient amendment. The study was conducted during 125 days with 5 sampling events (EM. During the study two analytical methods for the determination of total petroleum hydrocarbons (TPHs: Method D-5831 (ASTM and the modified extraction by mechanical agitation and gravimetric determination method (EAMG (EPA, 1994; Schawab et al., 1999 were evaluated and compared. To monitor the bioremediation physic-chemical (pH, % moisture, and nutrients and microbiological (heterotrophic and hydrocarbon degrader microorganisms parameters were evaluated. The highest TPH degradation rates were observed during the first 28 days in the SIS and FIC treatments (278 and 235 mgTPHs/kgdw/d, respectively compared to the controls (110 mgTPHs/kgdw/d. The abiotic control indicated that the intrinsic bioremediation was the main process during the TPH degradation. Although, there was not significant differences between treatments and the control without nutrients, SIS showed the highest TPH degradation (39% and 41% by D-5831 and EAMG methods, respectively. The low pH (4,1 at the end of the study and the low degraders numbers (1x103 NMP/gdw in the treatments could be the limiting factors to achieve higher degradations rates. Stenotrophomonas maltophilia was the predominant microorganism during the study (34%. Key words: biodegration, bioestimulation, TPHs, petroleum, nutrients.
Controlling the biodegradability of poly(butylene succinate-co-butylene adipate) (PBSA) by solvents used in the dried-gel process

Science.gov (United States)

Yamazaki, Hana; Kamitabira, Saya; Maeda, Tomoki; Hotta, Atsushi

Considering an environmentally friendly material, poly(butylene succinate-co-butylene adipate)(PBSA) is one of the attractive biodegradable plastics that can be eventually degraded into H2O and CO2 by neighboring water molecules and microorganisms after the disposal. In order to expand the application of PBSA, the precise control of the biodegradability of PBSA is necessary. In this study, the dried-gel process was introduced to control the biodegradability of PBSA. The dried PBSA gels were prepared by using three different solvents (toluene, cyclohexanone, and o-dichlorobenzene). The scanning electron microscopy (SEM) micrographs revealed that the PBSA prepared by toluene had smaller spherocrystals than the other PBSA dried-gels prepared by cyclohexanone or o-dichlorobenzene. The biodegradability testing by immersing the three types of PBSA in NaOH aq. showed that the percentage of the weight loss of the PBSA produced by toluene was the highest. The results indicated that the microstructures of PBSA could be controlled by changing solvents during the gel preparations, and that the biodegradability of PBSA could therefore be efficiently modified by changing solvents. This work was supported by a Grant-in-Aid for Scientific Research (A) (No. 15H02298 to A.H.) and a Grant-in-Aid for Research Activity Start-up (No.15H06586 to T.M.) from JSPS: KAKENHI\\x9D.
Improving the biodegradative capacity of subsurface bacteria

International Nuclear Information System (INIS)

Romine, M.F.; Brockman, F.J.

1993-04-01

The continual release of large volumes of synthetic materials into the environment by agricultural and industrial sources over the last few decades has resulted in pollution of the subsurface environment. Cleanup has been difficult because of the relative inaccessibility of the contaminants caused by their wide dispersal in the deep subsurface, often at low concentrations and in large volumes. As a possible solution for these problems, interest in the introduction of biodegradative bacteria for in situ remediation of these sites has increased greatly in recent years (Timmis et al. 1988). Selection of biodegradative microbes to apply in such cleanup is limited to those strains that can survive among the native bacterial and predator community members at the particular pH, temperature, and moisture status of the site (Alexander, 1984). The use of microorganisms isolated from subsurface environments would be advantageous because the organisms are already adapted to the subsurface conditions. The options are further narrowed to strains that are able to degrade the contaminant rapidly, even in the presence of highly recalcitrant anthropogenic waste mixtures, and in conditions that do not require addition of further toxic compounds for the expression of the biodegradative capacity (Sayler et al. 1990). These obstacles can be overcome by placing the genes of well-characterized biodegradative enzymes under the control of promoters that can be regulated by inexpensive and nontoxic external factors and then moving the new genetic constructs into diverse groups of subsurface microbes. ne objective of this research is to test this hypothesis by comparing expression of two different toluene biodegradative enzymatic pathways from two different regulatable promoters in a variety of subsurface isolates
Computational analysis for biodegradation of exogenously depolymerizable polymer

Science.gov (United States)

Watanabe, M.; Kawai, F.

2018-03-01

This study shows that microbial growth and decay in a biodegradation process of exogenously depolymerizable polymer are controlled by consumption of monomer units. Experimental outcomes for residual polymer were incorporated in inverse analysis for a degradation rate. The Gauss-Newton method was applied to an inverse problem for two parameter values associated with the microbial population. A biodegradation process of polyethylene glycol was analyzed numerically, and numerical outcomes were obtained.
Phonological Processes in Complex and Compound Words

Directory of Open Access Journals (Sweden)

Alieh Kord Zaferanlu Kambuziya

2016-02-01

Full Text Available Abstract This research at making a comparison between phonological processes in complex and compound Persian words. Data are gathered from a 40,000-word Persian dictionary. To catch some results, 4,034 complex words and 1,464 compound ones are chosen. To count the data, "excel" software is used. Some results of the research are: 1- "Insertion" is the usual phonological process in complex words. More than half of different insertions belongs to the consonant /g/. Then /y/ and // are in the second and the third order. The consonant /v/ has the least percentage of all. The most percentage of vowel insertion belongs to /e/. The vowels /a/ and /o/ are in the second and third order. Deletion in complex words can only be seen in consonant /t/ and vowel /e/. 2- The most frequent phonological processes in compounds is consonant deletion. In this process, seven different consonants including /t/, //, /m/, /r/, / ǰ/, /d, and /c/. The only deleted vowel is /e/. In both groups of complex and compound, /t/ deletion can be observed. A sequence of three consonants paves the way for the deletion of one of the consonants, if one of the sequences is a sonorant one like /n/, the deletion process rarely happens. 3- In complex words, consonant deletion causes a lighter syllable weight, whereas vowel deletion causes a heavier syllable weight. So, both of the processes lead to bi-moraic weight. 4- The production of bi-moraic syllable in Persian is preferable to Syllable Contact Law. So, Specific Rules have precedence to Universals. 5- Vowel insertion can be seen in both groups of complex and compound words. In complex words, /e/ insertion has the most fundamental part. The vowels /a/ and /o/ are in the second and third place. Whenever there are two sequences of ultra-heavy syllables. By vowel insertion, the first syllable is broken into two light syllables. The compounds that are influenced by vowel insertion, can be and are pronounced without any insertion
Radiation degradation and biodegradation in laundry wastes by γ irradiation

International Nuclear Information System (INIS)

Kuo, P.C.; Chou, T.S.

1984-01-01

The interaction of water and organic compounds by γ radiation leads to radiolysis effect. Three main results are obtained from the nonbiodegradable alkyl benzene sulfonate (ABS) irradiated with γ ray. Firstly, about 27.6% of ABS is destroyed at dosage of 1.9 x 10 4 rad and ABS is almost completely destroyed at 1.2 x 10 6 rad. Maximum decomposition of ABS occurs at pH = 6. Secondly, some low molecular weight compounds formed in ABS by radiation are volatilized and high molecular weight compounds formed in ABS are gels. At a dosage of 10 4 rad the weight percentage reduction of carbon, hydrogen, and sulfur in ABS reads 2.68, 1.15, and 3.15 respectively, while at 10 8 rad the same reduction reads 20.6, 18.5, and 22.0. Reduction of BOD in the waste water occurs at high dose. Thirdly, in biodegradation it is found that the bacteria propagation depends on the total radiation dose; the excess radiation dose produces macropolymers which may be more resistant to biodegradation than the parent. 8 references, 20 figures, 4 tables
Oil bioremediation processes in Brazilian marine environments : laboratory simulations

International Nuclear Information System (INIS)

Souza, E.S.; Triguis, J.A.

2003-01-01

Bioremediation methods have been used in Brazil to remediate contaminated soils from refinery residues. In particular, bioremediation is a process that can reduce the amount of oil that reaches shorelines, by enhancing natural biodegradation. This presentation presents the results of a laboratory study in which seawater contaminated with light crude oil was bioremediated in a period of 28 days using NPK fertilizer. Whole oil gas chromatography and gas chromatography-mass spectrometry analyses of the hydrocarbon fractions were used to determine the extent of oil biodegradation. It was determined that natural degradation occurred in the first 4 days, and mostly through the evaporation of light end n-alkanes. Biodegradation of n-alkanes was found to be most effective after 7 days, and no changes were observed in the relative abundance of steranes and triterpanes. It appears that the addition of NPK nutrient reduces the biodegradation potential of polyaromatic compounds. Seawater samples were also measured to determine the efficiency of bioremediation. The use of NPK fertilizer resulted in higher toxicity after 14 days probably due to the creation of metabolites as polyaromatic compounds biodegrade. Non toxic levels were found to be reestablished after 28 days of bioremediation. 16 refs., 4 tabs., 6 figs
Non-biodegradable landfill leachate treatment by combined process of agitation, coagulation, SBR and filtration.

Science.gov (United States)

Abood, Alkhafaji R; Bao, Jianguo; Du, Jiangkun; Zheng, Dan; Luo, Ye

2014-02-01

This study describes the complete treatment of non-biodegradable landfill leachate by combined treatment processes. The processes consist of agitation as a novel stripping method used to overcome the ammonia toxicity regarding aerobic microorganisms. The NH3-N removal ratio was 93.9% obtained at pH 11.5 and a gradient velocity (G) 150 s(-1) within a five-hour agitation time. By poly ferric sulphate (PFS) coagulation followed the agitation process; chemical oxygen demand (COD) and biological oxygen demand (BOD5) were removed at 70.6% and 49.4%, respectively at an optimum dose of 1200 mg L(-1) at pH 5.0. The biodegradable ratio BOD5/COD was improved from 0.18 to 0.31 during pretreatment step by agitation and PFS coagulation. Thereafter, the effluent was diluted with sewage at a different ratio before it was subjected to sequencing batch reactor (SBR) treatment. Up to 93.3% BOD5, 95.5% COD and 98.1% NH3-N removal were achieved by SBR operated under anoxic-aerobic-anoxic conditions. The filtration process was carried out using sand and carbon as a dual filter media as polishing process. The final effluent concentration of COD, BOD5, suspended solid (SS), NH3-N and total organic carbon (TOC) were 72.4 mg L(-1), 22.8 mg L(-1), 24.2 mg L(-1), 18.4 mg L(-1) and 50.8 mg L(-1) respectively, which met the discharge standard. The results indicated that a combined process of agitation-coagulation-SBR and filtration effectively eliminated pollutant loading from landfill leachate. Copyright © 2013 Elsevier Ltd. All rights reserved.
Analysis of anaerobic BTX biodegradation in a subarctic aquifer using isotopes and benzylsuccinates.

Science.gov (United States)

McKelvie, Jennifer R; Lindstrom, Jon E; Beller, Harry R; Richmond, Sharon A; Sherwood Lollar, Barbara

2005-12-01

In situ biodegradation of benzene, toluene, and xylenes in a petroleum hydrocarbon contaminated aquifer near Fairbanks, Alaska was assessed using carbon and hydrogen compound specific isotope analysis (CSIA) of benzene and toluene and analysis of signature metabolites for toluene (benzylsuccinate) and xylenes (methylbenzylsuccinates). Carbon and hydrogen isotope ratios of benzene were between -25.9 per thousand and -26.8 per thousand for delta13C and -119 per thousand and -136 per thousand for delta2H, suggesting that biodegradation of benzene is unlikely at this site. However, biodegradation of both xylenes and toluene were documented in this subarctic aquifer. Biodegradation of xylenes was indicated by the presence of methylbenzylsuccinates with concentrations of 17-50 microg/L in three wells. Anaerobic toluene biodegradation was also indicated by benzylsuccinate concentrations of 10-49 microg/L in the three wells with the highest toluene concentrations (1500-5000 microg/L toluene). Since benzylsuccinate typically accounts for a very small fraction of the toluene present in groundwater (generally data is particularly valuable given the challenge of verifying biodegradation in subarctic environments where degradation rates are typically much slower than in temperate environments.
Effect of activated carbon on biodegradation of organic micropollutants in water; Suichu biryo yuki busshitsu no biseibutsu bunkai ni oyobosu kasseitan no koka

Energy Technology Data Exchange (ETDEWEB)

Fukuhara, T.; Nakano, S. [Osaka Municipal Technical Research Institute, Osaka (Japan)

1997-01-10

The effect of activated carbon (AC) on biodegradation of organic micropollutants in water was investigated, using fenitrothion, phenol and aniline as the model compounds, activated sludges cultured in a mixed solution of glucose, peptone and aniline, and Rhodotorula glutinis isolated as the phenol-degradation bacterium. The following conclusions are obtained by analyzing the corrected degradation curves derived from the adsorption equilibrium relationships, oxygen consumption characteristics and observed degradation curves. Biodegradation of each compound is accelerated in the presence of AC. Non-biological degradation of fenitrothion is also accelerated in the presence of AC, its effect being more noted in biodegradation and increasing as AC quantity increases. Phenol is biodegraded by different mechanisms, depending on its initial concentration. The maximum oxygen consumption rate during the biodegradation of phenol increases in the presence of AC, conceivably resulting from enhanced bacterial activities. 5 refs., 6 figs., 4 tabs.
Contribution of microorganisms to non-extractable residue formation during biodegradation of ibuprofen in soil.

Science.gov (United States)

Nowak, Karolina M; Girardi, Cristobal; Miltner, Anja; Gehre, Matthias; Schäffer, Andreas; Kästner, Matthias

2013-02-15

Non-extractable residues (NER) formed during biodegradation of organic contaminants in soil are considered to be mainly composed of parent compounds or their primary metabolites with hazardous potential. However, in the case of biodegradable organic compounds, the soil NER may also contain microbial biomass components, for example fatty acids (FA) and amino acids (AA). After cell death, these biomolecules are subsequently incorporated into non-living soil organic matter (SOM) and are stabilised ultimately forming hardly extractable residues of biogenic origin. We investigated biodegradation of (13)C(6)-ibuprofen, in particular the metabolic incorporation of the (13)C-label into FA and AA and their fate in soil over 90 days. (13)C-FA and (13)C-AA amounts in the living microbial biomass fraction initially increased, then decreased over time and were continuously incorporated into the non-living SOM pool. The (13)C-FA in the non-living SOM remained stable from day 59 whereas the contents of (13)C-AA slightly increased until the end. After 90 days, nearly all NER were biogenic as they were made up almost completely by natural biomass compounds. The presented data demonstrated that the potential environmental risks related to the ibuprofen-derived NER are overestimated. Copyright © 2012 Elsevier B.V. All rights reserved.
Biodegradable Polymers

OpenAIRE

Vroman, Isabelle; Tighzert, Lan

2009-01-01

Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...
Biodegradation of phenol using an anaerobic EGSB reactors

International Nuclear Information System (INIS)

Eguia, A.; Olvera, M. E.; Cerezo, R.; Kuppusamy, I.

2009-01-01

Phenol is a compound found naturally in domestic and industrial waste waters and should be removed since in high concentrations it proves to be fatal. The present investigation was undertaken to evaluate the anaerobic biodegradability of the phenol in the wastewaters supplementing sulphates in the form of CaSO 4 2 , to increment the COD t otal removal value. (Author)
Estudo comparativo da caracterização de filmes biodegradáveis de amido de mandioca contendo polpas de manga e de acerola

Directory of Open Access Journals (Sweden)

Carolina Oliveira de Souza

2012-01-01

Full Text Available Most compounds reinforcements have been used to improve thermals, mechanical and barrier properties of biopolymers films, whose performance is usually poor when compared to those of synthetic polymers. Biodegradables films have been developed by adding mango and acerola pulps in different concentrations (0-17,1% w/w as antioxidants active compounds to cassava starch based biodegradable films. The effect of pulps was studied in terms of tensile properties, water vapor permeability, DSC, among other analysis of the films. The study demonstrated that the properties of cassava starch biodegradable films can be significantly altered through of incorporation mango and acerola pulps.
Monitoring of the aerobe biodegradation of chlorinated organic solvents by stable isotope analysis

Science.gov (United States)

Horváth, Anikó; Futó, István; Palcsu, László

2014-05-01

Our chemical-biological basic research aims to eliminate chlorinated environmental contaminants from aquifers around industrial areas in the frame of research program supported by the European Social Fund (TÁMOP-4.2.2.A-11/1/KONV-2012-0043). The most careful and simplest way includes the in situ biodegradation with the help of cultured and compound specific strains. Numerous members of Pseudomonas bacteria are famous about function of bioremediation. They can metabolism the environmental hazardous chemicals like gas oils, dyes, and organic solvents. Our research based on the Pseudomonas putida F1 strain, because its ability to degrade halogenated hydrocarbons such as trichloroethylene. Several methods were investigated to estimate the rate of biodegradation, such as the measurement of the concentration of the pollutant along the contamination pathway, the microcosm's studies or the compound specific stable isotope analysis. In this area in the Transcarpathian basin we are pioneers in the stable isotope monitoring of biodegradation. The main goal is to find stable isotope fractionation factors by stable isotope analysis, which can help us to estimate the rate and effectiveness of the biodegradation. The subsequent research period includes the investigation of the method, testing its feasibility and adaptation in the environment. Last but not least, the research gives an opportunity to identify the producer of the contaminant based on the stable isotope composition of the contaminant.
Bio-remediation of acephate-Pb(II) compound contaminants by Bacillus subtilis FZUL-33.

Science.gov (United States)

Lin, Wenting; Huang, Zhen; Li, Xuezhen; Liu, Minghua; Cheng, Yangjian

2016-07-01

Removal of Pb(2+) and biodegradation of organophosphorus have been both widely investigated respectively. However, bio-remediation of both Pb(2+) and organophosphorus still remains largely unexplored. Bacillus subtilis FZUL-33, which was isolated from the sediment of a lake, possesses the capability for both biomineralization of Pb(2+) and biodegradation of acephate. In the present study, both Pb(2+) and acephate were simultaneously removed via biodegradation and biomineralization in aqueous solutions. Batch experiments were conducted to study the influence of pH, interaction time and Pb(2+) concentration on the process of removal of Pb(2+). At the temperature of 25°C, the maximum removal of Pb(2+) by B.subtilis FZUL-33 was 381.31±11.46mg/g under the conditions of pH5.5, initial Pb(2+) concentration of 1300mg/L, and contact time of 10min. Batch experiments were conducted to study the influence of acephate on removal of Pb(2+) and the influence of Pb(2+) on biodegradation of acephate by B.subtilis FZUL-33. In the mixed system of acephate-Pb(2+), the results show that biodegradation of acephate by B.subtilis FZUL-33 released PO4(3+), which promotes mineralization of Pb(2+). The process of biodegradation of acephate was affected slightly when the concentration of Pb(2+) was below 100mg/L. Based on the results, it can be inferred that the B.subtilis FZUL-33 plays a significant role in bio-remediation of organophosphorus-heavy metal compound contamination. Copyright © 2016. Published by Elsevier B.V.
State-of-the-art of biodegradable composite materials

International Nuclear Information System (INIS)

Baley, Ch.; Grohens, Y.; Pillin, I.

2004-01-01

Nowadays, the market demand for environment friendly materials is in strong growth. The biodegradable composites (biodegradable fibres and polymers) mainly extracted from renewable resources will be a major contributor to the production of new industrial high performance products partially solving the problem of waste management. At the end of the lifetime, a structural bio-composite could be be crushed and recycled through a controlled industrial composting process. This the state-of-the-art report focuses on the biopolymers the vegetable fibres properties, the mechanisms of biodegradation and the examples of biodegradable composites. Eco-design of new products requires these new materials for which a life cycle analysis is nevertheless necessary to validate their environmental benefits. (authors)

Synthetic biodegradable functional polymers for tissue engineering: a brief review

OpenAIRE

BaoLin, GUO; MA, Peter X.

2014-01-01

Scaffolds play a crucial role in tissue engineering. Biodegradable polymers with great processing flexibility are the predominant scaffolding materials. Synthetic biodegradable polymers with well-defined structure and without immunological concerns associated with naturally derived polymers are widely used in tissue engineering. The synthetic biodegradable polymers that are widely used in tissue engineering, including polyesters, polyanhydrides, polyphosphazenes, polyurethane, and poly (glyce...
Biodegradation and Bioremediation of Petroleum Pollutants in Soil

Energy Technology Data Exchange (ETDEWEB)

Huesemann, Michael H.

2004-08-02

During bioremediation, petroleum hydrocarbons are converted by naturally occurring or indigenous soil microorganisms to carbon dioxide, water, bacterial cells (biomass), and humic materials. Numerous factors are known to affect both the rate and the extent of hydrocarbon biodegradation in contaminated soils. These include soil properties such as moisture content, aeration, nutrient status, pH, and temperature as well as waste characteristics such as the concentration and molecular structure of hydrocarbon compounds or classes, the presence of inhibitors and cometabolic substrates, and the degree of contaminant sequestration which often leads to serious bioavailability limitations, particularly in aged soils. It is the objective of this chapter to outline a strategy for optimizing the hydrocarbon bioremediation process by adjusting the various operational parameters so that none of them become a limiting factor during treatment.
Influence of Processing Techniques on Microstructure and Mechanical Properties of a Biodegradable Mg-3Zn-2Ca Alloy

Czech Academy of Sciences Publication Activity Database

Doležal, P.; Zapletal, J.; Fintová, Stanislava; Trojanová, Z.; Greger, M.; Roupcová, Pavla; Podrábský, T.

2016-01-01

Roč. 9, č. 11 (2016), s. 1-15, č. článku 880. ISSN 1996-1944 Institutional support: RVO:68081723 Keywords : biodegradable magnesium alloy * Mg-Zn-Ca * squeeze casting * ECAP processing * microstructure * mechanical properties Subject RIV: JP - Industrial Processing Impact factor: 2.654, year: 2016 http://www.mdpi.com/1996-1944/9/11/880
Processing method for drained water containing ethanol amine

International Nuclear Information System (INIS)

Wakuta, Kuniharu; Ogawa, Naoki; Sagawa, Hiroshi; Kamiyoshi, Hideki; Fukunaga, Kazuo; Iwamoto, Ken; Miki, Tsuyoshi; Hirata, Toshio

1998-01-01

Drained water containing ethanol amine is processed with microorganisms such as hydrazine resistant denitrification bacteria in a biodegrading vessel (A) in the coexistence of nitrous ions and/or nitric ions under an anaerobic condition, and then it is processed with microorganisms such as nitrification bacteria in another biotic oxidation vessel (B) under an aerobic condition to generate the coexistent nitrate ion and/or nitric ion, and returned to the biodegrading vessel (A). Further, they are exposed to air or incorporated with an oxidant and optionally a copper compound such as copper sulfate as a catalyst is added in a step of removing hydrazine. (T.M.)
Grey water biodegradability.

Science.gov (United States)

Ghunmi, Lina Abu; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

2011-02-01

Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different conditions in the biodegradation test. The maximum aerobic and anaerobic biodegradability and conversion rate for the different COD fractions is determined. The results show that, on average, dormitory grey water COD fractions are 28% suspended, 32% colloidal and 40% dissolved. The studied factors incubation time, inoculum addition and temperature are influencing the determined biodegradability. The maximum biodegradability and biodegradation rate differ between different COD fractions, viz. COD(ss), COD(col) and COD(diss). The dissolved COD fraction is characterised by the lowest degradation rate, both for anaerobic and aerobic conditions. The maximum biodegradability for aerobic and anaerobic conditions is 86 and 70% respectively, whereas the first order conversion rate constant, k₂₀, is 0.119 and 0.005 day⁻¹, respectively. The anaerobic and aerobic conversion rates in relation to temperature can be described by the Arrhenius relation, with temperature coefficients of 1.069 and 1.099, respectively.
Effect of growth conditions on the biodegradation kinetics of toluene by P. putida 54G in a vapor phase bioreactor

International Nuclear Information System (INIS)

Mirpuri, R.; Jones, W.; Krieger, E.; McFeters, G.

1994-01-01

Biodegradation of volatile organic compounds such as petroleum hydrocarbons and xenobiotic agents in the vapor phase is a promising new concept in well-head and end-of-pipe treatment which may have wide application where in-situ approaches are not feasible. The microbial degradation of the volatile organics can be carried out in vapor phase bioreactors which contain inert packing materials. Scale-up of these reactors from a bench scale to a pilot plant can best be achieved by the use of a predictive model, the success of which depends on accurate estimates of parameters defined in the model such as biodegradation kinetic and stoichiometric coefficients. The phenomena of hydrocarbon stress and injury may also affect performance of a vapor phase bioreactor. Batch kinetic studies on the biodegradation of toluene by P. Putida 54G will be compared to those obtained from continuous culture studies for both suspended and biofilm cultures of the same microorganism. These results will be compared to the activity of the P. putida 54G biofilm in a vapor phase bioreactor to evaluate the impact of hydrocarbon stress and injury on biodegradative processes
Biodegradation of hexachlorocyclohexane (HCH) by microorganisms.

Science.gov (United States)

Phillips, Theresa M; Seech, Alan G; Lee, Hung; Trevors, Jack T

2005-08-01

The organochlorine pesticide Lindane is the gamma-isomer of hexachlorocyclohexane (HCH). Technical grade Lindane contains a mixture of HCH isomers which include not only gamma-HCH, but also large amounts of predominantly alpha-, beta- and delta-HCH. The physical properties and persistence of each isomer differ because of the different chlorine atom orientations on each molecule (axial or equatorial). However, all four isomers are considered toxic and recalcitrant worldwide pollutants. Biodegradation of HCH has been studied in soil, slurry and culture media but very little information exists on in situ bioremediation of the different isomers including Lindane itself, at full scale. Several soil microorganisms capable of degrading, and utilizing HCH as a carbon source, have been reported. In selected bacterial strains, the genes encoding the enzymes involved in the initial degradation of Lindane have been cloned, sequenced, expressed and the gene products characterized. HCH is biodegradable under both oxic and anoxic conditions, although mineralization is generally observed only in oxic systems. As is found for most organic compounds, HCH degradation in soil occurs at moderate temperatures and at near neutral pH. HCH biodegradation in soil has been reported at both low and high (saturated) moisture contents. Soil texture and organic matter appear to influence degradation presumably by sorption mechanisms and impact on moisture retention, bacterial growth and pH. Most studies report on the biodegradation of relatively low (< 500 mg/kg) concentrations of HCH in soil. Information on the effects of inorganic nutrients, organic carbon sources or other soil amendments is scattered and inconclusive. More in-depth assessments of amendment effects and evaluation of bioremediation protocols, on a large scale, using soil with high HCH concentrations, are needed.
Biodegradation of PuEDTA and Impacts on Pu Mobility

International Nuclear Information System (INIS)

Xun, Luying; Bolton, Jr. Harvey

2001-01-01

Ethylenediaminetetraacetate (EDTA) and nitrilotriacetate (NTA) are synthetic chelating agents, which can form strong water-soluble complexes with radionuclides and metals and has been used to decontaminate and process nuclear materials. Synthetic chelating agents were co-disposed with radionuclides (e.g., 60Co, Pu) and heavy metals enhancing their transport in the subsurface. An understanding of EDTA biodegradation is essential to help mitigate enhanced radionuclide transport by EDTA. The objective of this research is to develop fundamental data on factors that govern the biodegradation of radionuclide-EDTA. These factors include the dominant EDTA aqueous species, the biodegradation of various metal-EDTA complexes, the uptake of various metal-EDTA complexes into the cell, the distribution and mobility of the radionuclide during and after EDTA biodegradation, and the enzymology and genetics of EDTA biodegradation
Biodegradation: Updating the Concepts of Control for Microbial Cleanup in Contaminated Aquifers

DEFF Research Database (Denmark)

Meckenstock, Rainer U.; Elsner, Martin; Griebler, Christian

2015-01-01

Biodegradation is one of the most favored and sustainable means of removing organic pollutants from contaminated aquifers but the major steering factors are still surprisingly poorly understood. Growing evidence questions some of the established concepts for control of biodegradation. Here, we...... on the controls of biodegradation in contaminant plumes. These include the plume fringe concept, transport limitations, and transient conditions as currently underestimated processes affecting biodegradation....
CHARACTERISTICS OF MUNICIPAL WASTE BIODEGRADABLE FRACTION AND EVALUATION OF ITS PROCESSING

Directory of Open Access Journals (Sweden)

Edward Meller

2015-11-01

Full Text Available A growing interest in Renewable Energy Sources initiated the use of biogas as an energy generating material. Biodegradable waste coming from different streams is an important resource for biogas production. The studies were conducted on 20–80 mm fraction of municipal waste separated by rotary screen in the technological process of The Waste Recovery and Storage Plant in Leśno Górne. Morphological composition of the examined waste and their parameters determining their usefulness for composting and fermentation were analysed. On the basis of organic carbon content, the amount of biogas that may be produced from 1 kg of waste was estimated. An approximate amount of biogas which can be obtained in the process of methane fermentation from energy piles, formed from 10 000 Mg of waste was also calculated. Depending on the temperature it was from. 2.8 to 3.8 mln m3.
Effects of Substitutions on the Biodegradation Potential of Benzotriazole Derivatives

Science.gov (United States)

Abu-Dalo, M. A.; O'Brien, I.; Hernandez, M. T.

2018-02-01

Fourteen benzotriazole derivatives were subjected to microcosm tests to study the influence of substitutions on their biodegradation potential. Methylated, nitrated, carboxylated, and propionated bezotriazoles, a heterocyclic triazole, as well as methylated benzimidazoles, were introduced to activated sludge and soil enrichment cultures as the only carbon source. Some of the enrichment cultures were derived from airport soils that had been previously contaminated with aircraft deicing fluids and subsequently enriched with the commercially significant corrosion inhibitor methylbenzotriazole. The 5-methylbenzotriazole and only the carboxylated derivatives were degraded by soil or activated sludge biomass regardless of acclimation conditions. Radiotracer studies of [U-14C] 5-methylbenzotriazole, and [U-14C] 5-carboxybenzotriazole confirmed that relatively high concentrations (25mg L-1) of these derivatives can be completely mineralized in relatively short time frames by microbial consortia regardless of prior exposure. Observations suggested that the growth yield on these compounds is likely low. Biodegradation patterns suggested that carboxylated benzotriazole derivatives are more readily biodegradable than their more popular methylated counterparts.
Kinetics of monomer biodegradation in soil.

Science.gov (United States)

Siotto, Michela; Sezenna, Elena; Saponaro, Sabrina; Innocenti, Francesco Degli; Tosin, Maurizio; Bonomo, Luca; Mezzanotte, Valeria

2012-01-01

In modern intensive agriculture, plastics are used in several applications (i.e. mulch films, drip irrigation tubes, string, clips, pots, etc.). Interest towards applying biodegradable plastics to replace the conventional plastics is promising. Ten monomers, which can be applied in the synthesis of potentially biodegradable polyesters, were tested according to ASTM 5988-96 (standard respirometric test to evaluate aerobic biodegradation in soil by measuring the carbon dioxide evolution): adipic acid, azelaic acid, 1,4-butanediol, 1,2-ethanediol, 1,6-hexanediol, lactic acid, glucose, sebacic acid, succinic acid and terephthalic acid. Eight replicates were carried out for each monomer for 27-45 days. The numerical code AQUASIM was applied to process the CO₂ experimental data in order to estimate values for the parameters describing the different mechanisms occurring to the monomers in soil: i) the first order solubilization kinetic constant, K(sol) (d⁻¹); ii) the first order biodegradation kinetic constant, K(b) (d⁻¹); iii) the lag time in biodegradation, t(lag) (d); and iv) the carbon fraction biodegraded but not transformed into CO₂, Y (-). The following range of values were obtained: [0.006 d⁻¹, 6.9 d⁻¹] for K(sol), [0.1 d⁻¹, 1.2 d⁻¹] for K(b), and [0.32-0.58] for Y; t(lag) was observed for azelaic acid, 1,2-ethanediol, and terephthalic acid, with estimated values between 3.0 e 4.9 d. Copyright © 2011 Elsevier Ltd. All rights reserved.
Polar Organic Pollutants in Groundwater: Experimental Approaches to Biodegradation During Subsoil Passage

Directory of Open Access Journals (Sweden)

T.P. Knepper

2002-01-01

Full Text Available A selection of polar organic compounds was investigated for their biodegradation on a laboratory scale fixed-bed bioreactor and the decline of the parent compounds besides the formation of metabolites was monitored. Of particular interest was the investigation into the degradation of pesticides, especially isoproturon (IPU, surfactants and industrial by-products of chemical synthesis. The results from the laboratory degradation experiments are compared to findings in groundwater.
Some functional limit theorems for compound Cox processes

Energy Technology Data Exchange (ETDEWEB)

Korolev, Victor Yu. [Faculty of Computational Mathematics and Cybernetics, Moscow State University, Moscow (Russian Federation); Institute of Informatics Problems FRC CSC RAS (Russian Federation); Chertok, A. V. [Faculty of Computational Mathematics and Cybernetics, Moscow State University, Moscow (Russian Federation); Euphoria Group LLC (Russian Federation); Korchagin, A. Yu. [Faculty of Computational Mathematics and Cybernetics, Moscow State University, Moscow (Russian Federation); Kossova, E. V. [Higher School of Economics National Research University, Moscow (Russian Federation); Zeifman, Alexander I. [Vologda State University, S.Orlova, 6, Vologda (Russian Federation); Institute of Informatics Problems FRC CSC RAS, ISEDT RAS (Russian Federation)

2016-06-08

An improved version of the functional limit theorem is proved establishing weak convergence of random walks generated by compound doubly stochastic Poisson processes (compound Cox processes) to Lévy processes in the Skorokhod space under more realistic moment conditions. As corollaries, theorems are proved on convergence of random walks with jumps having finite variances to Lévy processes with variance-mean mixed normal distributions, in particular, to stable Lévy processes.
Some functional limit theorems for compound Cox processes

International Nuclear Information System (INIS)

Korolev, Victor Yu.; Chertok, A. V.; Korchagin, A. Yu.; Kossova, E. V.; Zeifman, Alexander I.

2016-01-01

An improved version of the functional limit theorem is proved establishing weak convergence of random walks generated by compound doubly stochastic Poisson processes (compound Cox processes) to Lévy processes in the Skorokhod space under more realistic moment conditions. As corollaries, theorems are proved on convergence of random walks with jumps having finite variances to Lévy processes with variance-mean mixed normal distributions, in particular, to stable Lévy processes.
Process for compound transformation

KAUST Repository

Basset, Jean-Marie

2016-12-29

Embodiments of the present disclosure provide for methods of using a catalytic system to chemically transform a compound (e.g., a hydrocarbon). In an embodiment, the method does not employ grafting the catalyst prior to catalysis. In particular, embodiments of the present disclosure provide for a process of hydrocarbon (e.g., C1 to C20 hydrocarbon) metathesis (e.g., alkane, olefin, or alkyne metathesis) transformation, where the process can be conducted without employing grafting prior to catalysis.
Ageing processes and soil microbial community effects on the biodegradation of soil 13C-2,4-D nonextractable residues

International Nuclear Information System (INIS)

Lerch, T.Z.; Dignac, M.-F.; Nunan, N.; Barriuso, E.; Mariotti, A.

2009-01-01

The biodegradation of nonextractable residues (NER) of pesticides in soil is still poorly understood. The aim of this study was to evaluate the influence of NER ageing and fresh soil addition on the microbial communities responsible for their mineralisation. Soil containing either 15 or 90-day-old NER of 13 C-2,4-D (NER15 and NER90, respectively) was incubated for 90 days with or without fresh soil. The addition of fresh soil had no effect on the mineralisation of NER90 or of SOM, but increased the extent and rate of NER15 mineralisation. The analyses of 13 C-enriched FAME (fatty acids methyl esters) profiles showed that the fresh soil amendment only influenced the amount and structure of microbial populations responsible for the biodegradation of NER15. By coupling biological and chemical analyses, we gained some insight into the nature and the biodegradability of pesticide NER. - Ageing processes influence the NER mineralisation rate and the microbial population involved.
Hydrocarbons biodegradation in unsaturated porous medium; Biodegradation des hydrocarbures en milieu poreux insature

Energy Technology Data Exchange (ETDEWEB)

Gautier, C

2007-12-15

Biological processes are expected to play an important role in the degradation of petroleum hydrocarbons in contaminated soils. However, factors influencing the kinetics of biodegradation are still not well known, especially in the unsaturated zone. To address these biodegradation questions in the unsaturated zone an innovative experimental set up based on a physical column model was developed. This experimental set up appeared to be an excellent tool for elaboration of a structured porous medium, with well defined porous network and adjusted water/oil saturations. Homogeneous repartition of both liquid phases (i.e., aqueous and non aqueous) in the soil pores, which also contain air, was achieved using ceramic membranes placed at the bottom of the soil column. Reproducible interfaces (and connectivity) are developed between gas, and both non mobile water and NAPL phases, depending on the above-defined characteristics of the porous media and on the partial saturations of these three phases (NAPL, water and gas). A respirometric apparatus was coupled to the column. Such experimental set up have been validated with hexadecane in dilution in an HMN phase. This approach allowed detailed information concerning n-hexadecane biodegradation, in aerobic condition, through the profile of the oxygen consumption rate. We have taken benefit of this technique, varying experimental conditions, to determine the main parameters influencing the biodegradation kinetics and compositional evolution of hydrocarbons, under steady state unsaturated conditions and with respect to aerobic metabolism. Impacts of the nitrogen quantity and of three different grain sizes have been examined. Biodegradation of petroleum cut, as diesel cut and middle distillate without aromatic fraction, were, also studied. (author)
Phyllosphere yeasts rapidly break down biodegradable plastics

OpenAIRE

Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

2011-01-01

The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily ...
Aerobic biodegradation potential of endocrine disrupting chemicals in surface-water sediment at Rocky Mountains National Park, USA

Science.gov (United States)

Bradley, Paul M.; Battaglin, William A.; Iwanowicz, Luke R.; Clark, Jimmy M.; Journey, Celeste A.

2016-01-01

Endocrine disrupting chemicals (EDC) in surface water and bed sediment threaten the structure and function of aquatic ecosystems. In natural, remote, and protected surface-water environments where contaminant releases are sporadic, contaminant biodegradation is a fundamental driver of exposure concentration, timing, duration, and, thus, EDC ecological risk. Anthropogenic contaminants, including known and suspected EDC, were detected in surface water and sediment collected from 2 streams and 2 lakes in Rocky Mountains National Park (ROMO). The potential for aerobic EDC biodegradation was assessed in collected sediments using 6 14C-radiolabeled model compounds. Aerobic microbial mineralization of natural (estrone and 17β-estradiol) and synthetic (17α-ethinylestradiol) estrogen was significant at all sites. ROMO bed sediment microbial communities also effectively degraded the xenoestrogens, bisphenol-A and 4-nonylphenol. The same sediment samples exhibited little potential for aerobic biodegradation of triclocarban, however, illustrating the need to assess a wider range of contaminant compounds. The current results support recent concerns over the widespread environmental occurrence of carbanalide antibacterials, like triclocarban and triclosan, and suggest that backcountry use of products containing these compounds should be discouraged.

Improved cell activity on biodegradable photopolymer scaffolds using titanate nanotube coatings

Energy Technology Data Exchange (ETDEWEB)

Beke, S., E-mail: szabolcs.beke@iit.it [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Barenghi, R. [IEIIT, National Research Council (CNR), Via De Marini 6, 16149 Genova (Italy); Farkas, B.; Romano, I. [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632 Pécs (Hungary); Scaglione, S. [IEIIT, National Research Council (CNR), Via De Marini 6, 16149 Genova (Italy); Brandi, F. [Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, 56124-Pisa (Italy)

2014-11-01

The development of bioactive materials is in the premise of tissue engineering. For several years, surface functionalization of scaffolds has been one of the most promising approaches to stimulate cellular activity and finally improve implant success. Herein, we describe the development of a bioactive composite scaffold composed of a biodegradable photopolymer scaffold and titanate nanotubes (TNTs). The biodegradable photopolymer scaffolds were fabricated by applying mask-projection excimer laser photocuring at 308 nm. TNTs were synthesized and then spin-coated on the porous scaffolds. Upon culturing fibroblast cells on scaffolds, we found that nanotubes coating affects cell viability and proliferation demonstrating that TNT coatings enhance cell growth on the scaffolds by further improving their surface topography. - Highlights: • Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. • Titanate nanotube deposition was carried out without binding compounds or additives. • Titanate nanotube coatings enhanced cell viability and proliferation.
Characterization of selected municipal solid waste components to estimate their biodegradability.

Science.gov (United States)

Bayard, R; Benbelkacem, H; Gourdon, R; Buffière, P

2018-06-15

Biological treatments of Residual Municipal Solid Waste (RMSW) allow to divert biodegradable materials from landfilling and recover valuable alternative resources. The biodegradability of the waste components needs however to be assessed in order to design the bioprocesses properly. The present study investigated complementary approaches to aerobic and anaerobic biotests for a more rapid evaluation. A representative sample of residual MSW was collected from a Mechanical Biological Treatment (MBT) plant and sorted out into 13 fractions according to the French standard procedure MODECOM™. The different fractions were analyzed for organic matter content, leaching behavior, contents in biochemical constituents (determined by Van Soest's acid detergent fiber method), Biochemical Oxygen Demand (BOD) and Bio-Methane Potential (BMP). Experimental data were statistically treated by Principal Components Analysis (PCA). Cumulative oxygen consumption from BOD tests and cumulative methane production from BMP tests were found to be positively correlated in all waste fractions. No correlation was observed between the results from BOD or BMP bioassays and the contents in cellulose-like, hemicelluloses-like or labile organic compounds. No correlation was observed either with the results from leaching tests (Soluble COD). The contents in lignin-like compounds, evaluated as the non-extracted RES fraction in Van Soest's method, was found however to impact negatively the biodegradability assessed by BOD or BMP tests. Since cellulose, hemicelluloses and lignin are the polymers responsible for the structuration of lignocellulosic complexes, it was concluded that the structural organization of the organic matter in the different waste fractions was more determinant on biodegradability than the respective contents in individual biopolymers. Copyright © 2017 Elsevier Ltd. All rights reserved.
Environmental persistence of pesticides and their ecotoxicity: A review of natural degradation processes

International Nuclear Information System (INIS)

Narvaez Valderrama, Jhon Fredy; Palacio Baena, Jaime Alberto; Molina Perez, Francisco Jose

2012-01-01

Pesticides are allochthonous pollutants discharged in natural environments. Once in the environment, natural factors such as biodegradation, photodegradation and chemical hydrolysis trigger partial or total pesticide transformation and reduce their environmental persistence. However, some degraded compounds have a greater ecotoxicological effect on the biota that the parent compounds and the change in the physicochemical properties increase the bioaccumulation, toxicity and transference processes. Therefore, knowledge about degradation processes in the environment is crucial in studies related to the dynamics and behavior of these substances in the environment and the impact on aquatic and terrestrial ecosystems. This review aims to show the influence of natural degradation processes on the persistence of pesticides, their ecotoxicity and dynamics. Also discuss the application of the degradation processes in water treatment and pesticides removal. While biodegradation processes have been improved by using genetically engineered microorganisms, in the photodegradation has been applied advanced oxidation technologies (TAOS) in the treatment of water contaminated with pesticides.
Application of Transforms in a Compound Demands Process

Directory of Open Access Journals (Sweden)

Ou Tang

2012-10-01

Full Text Available The compound distribution is of interest for the study of inventoryproblem, since it provides a more flexible description ofthe stochastic properties of the system compared to many otherapproaches such as renewal processes. However, due to the difficultiesof obtaining analytical results for the compound distribution,such a type of study is usually limited to searching for agood approximation for replacing the complex model. This paperinvestigates the possibility to extend a previous stochastic inventorymodel to cover a compound demand process. Transformmethods again play an imp01tant role in the analysis forcapturing the stochastic prope1ties of the compound distribution.
Radiation effects on biodegradable polyesters

International Nuclear Information System (INIS)

Hiroshi Mitomo; Darmawan Darwis; Fumio Yoshii; Keizo Makuuchi

1999-01-01

Poly(3-hydroxybutyrate) [P(3HB)] and its copolymer poly(3-hydroxybutyrate-co-3hydroxyvalerate) [P(3HB-co-3HV)] are microbial biodegradable polyesters produced by many types of bacteria. Poly(butylene succinate) (PBS) and poly(E-caprolactone) (PCL) are also biodegradable synthetic polyesters which have been commercialized. These thermoplastics are expected for wide usage in environmental protection and blocompatible applications. Radiation grafting of hydrophilic monomers onto many polymers, e.g., polyethylene and polypropylene has been studied mainly for biomedical applications. In the present study, radiation-induced graft polymerization of vinyl monomers onto PHB and P(3HB-co-3HV) was carried out and improvement of their properties was studied. Changes in the properties and biodegradability were compared with the degree of grafting. Radiation-induced crosslinking of PBS and PCL which relatively show thermal and irradiation stability was also carried out to improve their thermal stability or processability. Irradiation to PBS and PCL mainly resulted in crosslinking and characterization of these crosslinked polyesters was investigated
Stable carbon isotope fractionation during the biodegradation of lambda-cyhalothrin

Energy Technology Data Exchange (ETDEWEB)

Shen, Xiaoli [MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Department of Environmental Engineering, Quzhou University, Quzhou 324000 (China); Xu, Zemin [MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Zhang, Xichang [Laboratory for Teaching in Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Yang, Fangxing, E-mail: fxyang@zju.edu.cn [MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Department of Effect-Directed Analysis, Helmholtz Centre for Environmental Research — UFZ, Leipzig 04318 (Germany)

2015-11-01

In this study, the microbial degradation of lambda-cyhalothrin in soil was investigated using compound-specific stable isotope analysis. The results revealed that lambda-cyhalothrin was biodegraded in soil under laboratory conditions. The half-lives of lambda-cyhalothrin were determined to be 49 and 161 days in non-sterile and sterile soils spiked with 2 mg/kg lambda-cyhalothrin and 84 and 154 days in non-sterile and sterile soils spiked with 10 mg/kg lambda-cyhalothrin, respectively. The biodegradation of lambda-cyhalothrin resulted in carbon isotope fractionation, which shifted from − 29.0‰ to − 26.5‰ in soil spiked with 2 mg/kg lambda-cyhalothrin, and to − 27.5‰ with 10 mg/kg lambda-cyhalothrin. A relationship was established between the stable carbon isotope fraction and the residual concentrations of lambda-cyhalothrin by the Rayleigh equation in which the carbon isotope enrichment factor ε of the microbial degradation of lambda-cyhalothrin in the soil was calculated as − 2.53‰. This study provides an approach to quantitatively evaluate the biodegradation of lambda-cyhalothrin in soil in field studies. - Highlights: • Abiotic and biotic degradation of lambda-cyhalothrin were observed in soil. • Biodegradation of lambda-cyhalothrin was evaluated by CSIA. • Biodegradation of lambda-cyhalothrin leads to carbon isotope fractionation. • An enrichment factor ε of lambda-cyhalothrin was determined as − 2.53‰.
Stable carbon isotope fractionation during the biodegradation of lambda-cyhalothrin

International Nuclear Information System (INIS)

Shen, Xiaoli; Xu, Zemin; Zhang, Xichang; Yang, Fangxing

2015-01-01

In this study, the microbial degradation of lambda-cyhalothrin in soil was investigated using compound-specific stable isotope analysis. The results revealed that lambda-cyhalothrin was biodegraded in soil under laboratory conditions. The half-lives of lambda-cyhalothrin were determined to be 49 and 161 days in non-sterile and sterile soils spiked with 2 mg/kg lambda-cyhalothrin and 84 and 154 days in non-sterile and sterile soils spiked with 10 mg/kg lambda-cyhalothrin, respectively. The biodegradation of lambda-cyhalothrin resulted in carbon isotope fractionation, which shifted from − 29.0‰ to − 26.5‰ in soil spiked with 2 mg/kg lambda-cyhalothrin, and to − 27.5‰ with 10 mg/kg lambda-cyhalothrin. A relationship was established between the stable carbon isotope fraction and the residual concentrations of lambda-cyhalothrin by the Rayleigh equation in which the carbon isotope enrichment factor ε of the microbial degradation of lambda-cyhalothrin in the soil was calculated as − 2.53‰. This study provides an approach to quantitatively evaluate the biodegradation of lambda-cyhalothrin in soil in field studies. - Highlights: • Abiotic and biotic degradation of lambda-cyhalothrin were observed in soil. • Biodegradation of lambda-cyhalothrin was evaluated by CSIA. • Biodegradation of lambda-cyhalothrin leads to carbon isotope fractionation. • An enrichment factor ε of lambda-cyhalothrin was determined as − 2.53‰
Biodegradation of endocrine-disrupting compounds and suppresion of estrogenic activity by ligninolytic fungi

Czech Academy of Sciences Publication Activity Database

Cajthaml, Tomáš; Křesinová, Zdena; Svobodová, Kateřina; Moeder, M.

2009-01-01

Roč. 75, č. 6 (2009), s. 745-750 ISSN 0045-6535 R&D Projects: GA MŠk LC06066; GA MŠk 2B06156; GA AV ČR KJB600200613 Institutional research plan: CEZ:AV0Z50200510 Keywords : Biodegradation * Endocrine disrupters * White rot fungi Subject RIV: EE - Microbiology, Virology Impact factor: 3.253, year: 2009
Characterization of biodegradation intermediates of nonionic surfactants by MALDI-MS. 2. Oxidative biodegradation profiles of uniform octylphenol polyethoxylate in 18O-labeled water.

Science.gov (United States)

Sato, Hiroaki; Shibata, Atsushi; Wang, Yang; Yoshikawa, Hiromichi; Tamura, Hiroto

2003-01-01

This paper reports the characterization of the biodegradation intermediates of octylphenol octaethoxylate (OP(8)EO) by means of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The biodegradation test study was carried out in a pure culture (Pseudomonas putida S-5) under aerobic conditions using OP(8)EO as the sole carbon source and (18)O-labeled water as an incubation medium. In the MALDI-MS spectra of biodegraded samples, a series of OP(n)EO molecules with n = 2-8 EO units and their corresponding carboxylic acid products (OP(n)EC) were observed. The use of purified OP(8)EO enabled one to distinguish the shortened OPEO molecules as biodegradation intermediates. Furthermore, the formation of OP(8)EC (the oxidized product of OP(8)EO) supported the notion that terminal oxidation is a step in the biodegradation process. When biodegradation study was carried out in (18)O-labeled water, incorporation of (18)O atoms into the carboxyl group was observed for OPEC, while no incorporation was observed for the shortened OPEO products. These results could provide some rationale to the biodegradation mechanism of alkylphenol polyethoxylates.
Phyllosphere yeasts rapidly break down biodegradable plastics.

Science.gov (United States)

Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-Hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

2011-11-29

The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands.
Phyllosphere yeasts rapidly break down biodegradable plastics

Science.gov (United States)

2011-01-01

The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands. PMID:22126328
Enhancement of biodegradability of real textile and dyeing wastewater by electron beam irradiation

International Nuclear Information System (INIS)

He, Shijun; Sun, Weihua; Wang, Jianlong; Chen, Lvjun; Zhang, Youxue; Yu, Jiang

2016-01-01

A textile and dyeing wastewater treatment plant is going to be upgraded due to the stringent discharge standards in Jiangsu province, China, and electron beam irradiation is considering to be used. In order to determine the suitable location of the electron accelerator in the process of wastewater treatment plant, the effects of electron beam (EB) irradiation on the biodegradability of various real wastewater samples collecting from the different stages of the wastewater treatment plant, the values of chemical oxygen demand (COD), biochemical oxygen demand (BOD 5 ), and the ratio of BOD 5 and COD (BOD 5 /COD), were compared before and after EB irradiation. During EB irradiation process, color indices and absorbance at 254 nm wavelength (UV 254 ) of wastewater were also determined. The results showed that EB irradiation pre-treatment cannot improve the biodegradability of raw textile and dyeing wastewater, which contains a large amount of biodegradable organic matters. In contrast, as to the final effluent of biological treatment process, EB irradiation can enhance the biodegradability to 224%. Therefore, the promising way is to apply EB irradiation as a post-treatment of the conventional biological process. - Highlights: • Irradiation pre-treatment did not improve the raw textile wastewater biodegradability. • Irradiation can highly enhance the biodegradability of biological treated effluent. • EB irradiation can be used as a post-treatment after biological process.
Biodegradation of chlorinated ethenes by a methane-utilizing mixed culture

International Nuclear Information System (INIS)

Fogel, M.M.; Taddeo, A.R.; Fogel, S.

1986-01-01

Chlorinated ethenes are toxic substances which are widely distributed groundwater contaminants and are persistent in the subsurface environment. Reports on the biodegradation of these compounds under anaerobic conditions which might occur naturally in groundwater show that these substances degrade very slowly, if at all. Previous attempts to degrade chlorinated ethenes aerobically have produced conflicting results. A mixed culture containing methane-utilizing bacteria was obtained by methane enrichment of a sediment sample. Biodegradation experiments carried out in sealed culture bottles with radioactively labeled trichloroethylene (TCE) showed that approximately half of the radioactive carbon had been converted to 14 CO 2 and bacterial biomass. In addition to TCE, vinyl chloride and vinylidene chloride could be degraded to products which are not volatile chlorinated substances and are therefore likely to be further degraded to CO 2 . Two other chlorinated ethenes, cis and trans-1,2-dichloroethylene, were shown to degrade to chlorinated products, which appeared to degrade further. A sixth chlorinated ethene, tetrachloroethylene, was not degraded by the methane-utilizing culture under these conditions. The biodegradation of TCE was inhibited by acetylene, a specific inhibitor of methane oxidation by methanotrophs. This observation supported the hypothesis that a methanotroph is responsible for the observed biodegradations
Bioavailability of hydrocarbons to bacterial consortia during Triton X-100 mediated biodegradation in aqueous media.

Science.gov (United States)

Pęziak, Daria; Piotrowska, Aleksandra; Marecik, Roman; Lisiecki, Piotr; Woźniak, Marta; Szulc, Alicja; Ławniczak, Łukasz; Chrzanowski, Łukasz

2013-01-01

The aim of our study was to investigate the effect of Triton X-100 on the biodegradation efficiency of hexadecane and phenanthrene carried out by two bacterial consortia. It was established that the tested consortia were not able to directly uptake compounds closed in micelles. It was observed that in micellar systems the nonionic synthetic surfactant was preferentially degraded (the degradation efficiency of Triton X-100 after 21 days was 70% of the initial concentration - 500 mg/l), followed by a lesser decomposition of hydrocarbon released from the micelles (30% for hexadecane and 20% for phenanthrene). However, when hydrocarbons were used as the sole carbon source, 70% of hexadecane and 30% of phenanthrene were degraded. The degradation of the surfactant did not contribute to notable shifts in bacterial community dynamics, as determined by Real-Time PCR. The obtained results suggest that if surfactant-supplementation is to be used as an integral part of a bioremediation process, then possible bioavailability decrease due to entrapment of the contaminant into surfactant micelles should also be taken into consideration, as this phenomenon may have a negative impact on the biodegradation efficiency. Surfactant-induced mobilization of otherwise recalcitrant hydrocarbons may contribute to the spreading of contaminants in the environment and prevent their biodegradation.
Comparative study of biodegradability prediction of chemicals using decision trees, functional trees, and logistic regression.

Science.gov (United States)

Chen, Guangchao; Li, Xuehua; Chen, Jingwen; Zhang, Ya-Nan; Peijnenburg, Willie J G M

2014-12-01

Biodegradation is the principal environmental dissipation process of chemicals. As such, it is a dominant factor determining the persistence and fate of organic chemicals in the environment, and is therefore of critical importance to chemical management and regulation. In the present study, the authors developed in silico methods assessing biodegradability based on a large heterogeneous set of 825 organic compounds, using the techniques of the C4.5 decision tree, the functional inner regression tree, and logistic regression. External validation was subsequently carried out by 2 independent test sets of 777 and 27 chemicals. As a result, the functional inner regression tree exhibited the best predictability with predictive accuracies of 81.5% and 81.0%, respectively, on the training set (825 chemicals) and test set I (777 chemicals). Performance of the developed models on the 2 test sets was subsequently compared with that of the Estimation Program Interface (EPI) Suite Biowin 5 and Biowin 6 models, which also showed a better predictability of the functional inner regression tree model. The model built in the present study exhibits a reasonable predictability compared with existing models while possessing a transparent algorithm. Interpretation of the mechanisms of biodegradation was also carried out based on the models developed. © 2014 SETAC.
Compound-Specific Isotope Analyses to Assess TCE Biodegradation in a Fractured Dolomitic Aquifer.

Science.gov (United States)

Clark, Justin A; Stotler, Randy L; Frape, Shaun K; Illman, Walter A

2017-01-01

The potential for trichloroethene (TCE) biodegradation in a fractured dolomite aquifer at a former chemical disposal site in Smithville, Ontario, Canada, is assessed using chemical analysis and TCE and cis-DCE compound-specific isotope analysis of carbon and chlorine collected over a 16-month period. Groundwater redox conditions change from suboxic to much more reducing environments within and around the plume, indicating that oxidation of organic contaminants and degradation products is occurring at the study site. TCE and cis-DCE were observed in 13 of 14 wells sampled. VC, ethene, and/or ethane were also observed in ten wells, indicating that partial/full dechlorination has occurred. Chlorine isotopic values (δ 37 Cl) range between 1.39 to 4.69‰ SMOC for TCE, and 3.57 to 13.86‰ SMOC for cis-DCE. Carbon isotopic values range between -28.9 and -20.7‰ VPDB for TCE, and -26.5 and -11.8‰ VPDB for cis-DCE. In most wells, isotopic values remained steady over the 15-month study. Isotopic enrichment from TCE to cis-DCE varied between 0 and 13‰ for carbon and 1 and 4‰ for chlorine. Calculated chlorine-carbon isotopic enrichment ratios (ϵ Cl /ϵ C ) were 0.18 for TCE and 0.69 for cis-DCE. Combined, isotopic and chemical data indicate very little dechlorination is occurring near the source zone, but suggest bacterially mediated degradation is occurring closer to the edges of the plume. © 2016, National Ground Water Association.
Effect of agroforestry residues partially biodegraded by pleurotus ostreatus (pleurotaceae) on tomato seedlings development

International Nuclear Information System (INIS)

Luna Fontalvo, Jorge Alberto; Cordoba Lopez, Laura Sofia; Gil Pertuz, Karina Isabel; Romero Borja, Isaac Manuel

2013-01-01

It was evaluated the development of tomato seedlings (plant bioindicator of toxicity) in soils with sawdust and rice husk partially biodegraded by Pleurotus ostreatus in greenhouse conditions. Both organic compounds (carbon, cellulose, lignin, extractives, and organic matter), and inorganic compounds (nitrogen, phosphorus and pH) were determined, before and after fungus inoculation on sawdust and rice husk. Mixtures were held of each substrate with a nutrient poor soil in equal proportions (1:1) and the moisture content was determined. The experiment consisted of a completely randomized, with two groups of six treatments for each substrate, and 30 days later, parameters of growth and development were identified. biodegraded substrates presented low C, N and P. bsa + sf treatment (biodegraded sawdust + fertilized soil) presented the best results in the number of leaves (12.9), plant height (25.94 cm), root length (5.92 cm), dry weight (0.138 g), and fresh weight (1.012 g). bsa + sf substrate can work as favorable substrate for growing tomato seedlings, bsa + sf substrate can work as favorable substrate for growing of tomato seedlings, since it provides the nutrients necessary for a good growth. Plants in rice bran did not grow adequately for transplanting.
Process for production of a borohydride compound

Science.gov (United States)

Allen, Nathan Tait; Butterick, III, Robert; Chin, Arthur Achhing; Millar, Dean Michael; Molzahn, David Craig

2014-08-19

A process for production of a borohydride compound M(BH.sub.4).sub.y. The process has three steps. The first step combines a compound of formula (R.sup.1O).sub.yM with aluminum, hydrogen and a metallic catalyst containing at least one metal selected from the group consisting of titanium, zirconium, hafnium, niobium, vanadium, tantalum and iron to produce a compound of formula M(AlH.sub.3OR.sup.1).sub.y, wherein R.sup.1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group; M is an alkali metal, Be or Mg; and y is one or two; wherein the catalyst is present at a level of at least 200 ppm based on weight of aluminum. The second step combines the compound of formula M(AlH.sub.3OR.sup.1).sub.y with a borate, boroxine or borazine compound to produce M(BH.sub.4).sub.y and a byproduct mixture containing alkali metal and aluminum aryloxides. The third step separates M(BH.sub.4).sub.y from the byproduct mixture.
Detailed Modelling of Kinetic Biodegradation Processes in a Laboratory Mmicrocosm

Science.gov (United States)

Watson, I.; Oswald, S.; Banwart, S.; Mayer, U.

2003-04-01

Biodegradation of organic contaminants in soil and groundwater usually takes places via different redox processes happening sequentially as well as simultaneously. We used numerical modelling of a long-term lab microcosm experiment to simulate the dynamic behaviour of fermentation and respiration in the aqueous phase in contact with the sandstone material, and to develop a conceptual model describing these processes. Aqueous speciation, surface complexation, mineral dissolution and precipitation were taken into account also. Fermentation can be the first step of the degradation process producing intermediate species, which are subsequently consumed by TEAPs. Microbial growth and substrate utilisation kinetics are coupled via a formulation that also includes aqueous speciation and other geochemical reactions including surface complexation, mineral dissolution and precipitation. Competitive exclusion between TEAPs is integral to the conceptual model of the simulation, and the results indicate that exclusion is not complete, but some overlap is found between TEAPs. The model was used to test approaches like the partial equilibrium approach that currently make use of hydrogen levels to diagnose prevalent TEAPs in groundwater. The observed pattern of hydrogen and acetate concentrations were reproduced well by the simulations, and the results show the relevance of kinetics, lag times and inhibition, and especially that intermediate products play a key role.
Anaerobic biodegradability of macropollutants

DEFF Research Database (Denmark)

Angelidaki, Irini

2002-01-01

A variety of test procedures for determination of anaerobic biodegradability has been reported. This paper reviews the methods developed for determination of anaerobic biodegradability of macro-pollutants. Anaerobic biodegradability of micro-pollutants is not included. Furthermore, factors...

Biodegradação de alcoóis, ftalatos e adipatos em um solo tropical contaminado Biodegradation of alcohol, phthalates and adipates in a tropical soil

Directory of Open Access Journals (Sweden)

Ieda Domingues Ferreira

2010-01-01

Full Text Available The adipic and phthalic acid esters are plasticizers, have low water solubility, high partition octanol/water coefficients (Kow and accumulate in soil and sediments. These compounds are considered teratogenic, carcinogenic and endocrine disruptors chemicals. This study evaluated the bioremediation of tropical soil contaminated with plasticizers process wastes, in aerobic conditions, with and without introduction of acclimated bacteria. It was selected 200 kg of contaminated tropical soil for the biodegradation study. The plasticizers concentrations in soil ranged between 153 mgDOA/kg up to 15552 mgDIDP/kg and after 90 days of biodegradation, the lower removal efficiencies were 72% with a 1-2 log simultaneous bacterial growth.
Biodegradation and bioremediation

DEFF Research Database (Denmark)

Albrechtsen, H.-J.

1996-01-01

Anmeldelse af Alexander,M.: Biodegradation and bioremediation. Academic Press, Sandiego, USA, 1994......Anmeldelse af Alexander,M.: Biodegradation and bioremediation. Academic Press, Sandiego, USA, 1994...
Kinetics of the biodegradation of green table olive wastewaters by aerobic and anaerobic treatments

International Nuclear Information System (INIS)

Beltran, J.; Gonzalez, T.; Garcia, J.

2008-01-01

The biodegradation of the organic pollutant matter present in green table olive wastewater (GTOW) is studied in batch reactors by an aerobic biodegradation and by an anaerobic digestion. In the aerobic biodegradation, the evolution of the substrate (in terms of chemical and biochemical oxygen demand), biomass, and total polyphenolic compounds present in the wastewater are followed during the process, and a kinetic study is performed using Contois' model, which when applied to the experimental results provides the kinetic parameter of this model, resulting in a modified Contois' equation (q = 3.3S/(0.31S 0 X + X), gCOD/gVSS d -1 ). Other kinetic parameters were determined: the cellular yield coefficient (Y X/S = 5.7 x 10 -2 gVSS/gCOD) and the kinetic constant of cellular death phase (k d = 0.16 d -1 ). Similarly, in the anaerobic digestion, the evolution of the substrate digested and the methane produced are followed, and the kinetic study is conducted using a modified Monod model combined with the Levenspiel model, due to the presence of inhibition effects. This model leads to the determination of the kinetic parameters: kinetic constant when no inhibitory substance is present (k M0 = 8.4 x 10 -2 h -1 ), critical substrate concentration of inhibition (TP* = 0.34 g/L) and inhibitory parameter (n = 2.25)
Bacterial production of the biodegradable plastics polyhydroxyalkanoates.

Science.gov (United States)

Urtuvia, Viviana; Villegas, Pamela; González, Myriam; Seeger, Michael

2014-09-01

Petroleum-based plastics constitute a major environmental problem due to their low biodegradability and accumulation in various environments. Therefore, searching for novel biodegradable plastics is of increasing interest. Microbial polyesters known as polyhydroxyalkanoates (PHAs) are biodegradable plastics. Life cycle assessment indicates that PHB is more beneficial than petroleum-based plastics. In this report, bacterial production of PHAs and their industrial applications are reviewed and the synthesis of PHAs in Burkholderia xenovorans LB400 is described. PHAs are synthesized by a large number of microorganisms during unbalanced nutritional conditions. These polymers are accumulated as carbon and energy reserve in discrete granules in the bacterial cytoplasm. 3-hydroxybutyrate and 3-hydroxyvalerate are two main PHA units among 150 monomers that have been reported. B. xenovorans LB400 is a model bacterium for the degradation of polychlorobiphenyls and a wide range of aromatic compounds. A bioinformatic analysis of LB400 genome indicated the presence of pha genes encoding enzymes of pathways for PHA synthesis. This study showed that B. xenovorans LB400 synthesize PHAs under nutrient limitation. Staining with Sudan Black B indicated the production of PHAs by B. xenovorans LB400 colonies. The PHAs produced were characterized by GC-MS. Diverse substrates for the production of PHAs in strain LB400 were analyzed. Copyright © 2014 Elsevier B.V. All rights reserved.
Biodegradation of Crystal Violet by Agrobacterium radiobacter

DEFF Research Database (Denmark)

Parshetti, G.K.; Parshetti, S.G.; Telke, A.A.

2011-01-01

Violet (100 mg/L) was studied, maximum decolorization was observed with 15% inoculum concentration. A significant increase in the activities of laccase (184%) and aminopyrine Af-demethylase (300%) in cells obtained after decolorization indicated the involvement of these enzymes in decolorization process...... and phenol. We proposed the hypothetical metabolic pathway of Crystal Violet biodegradation by A. radiobacter. Phytotoxicity and microbial toxicity study showed that Crystal Violet biodegradation metabolites were less toxic to bacteria (A. radiobacter, P. aurugenosa and A. vinelandii) contributing to soil...
Benzene biodegradation using an anaerobic column coupled to Mn(IV) reduction

Energy Technology Data Exchange (ETDEWEB)

Villatoro-Monzon, W.R.; Velasquez-Mejia, E.K.; Morales-Ibarria, M.G.; Razo-Flores, E. [Instituto Mexicano del Petroleo (Mexico). Programo de Biotenologia del Petroleo

2004-07-01

Benzene, toluene, and o, m, p-xylene compounds make up a large proportion of gasoline. Due to spills and leaks from underground tanks, these compounds frequently contaminate groundwater and sediment. In particular the high solubility of benzene makes it very mobile and an extra danger to groundwater. Moreover, there are strong links between benzene and cancer and thus benzene is considered a serious pollutant. Contaminated sites usually become anaerobic due to microbe action. In this study, benzene biodegradation was done in a glass column inoculated with anaerobic Rhine River sediment and using Mn(IV) as the final electron acceptor. Under steady state operation, benzene biodegradation efficiency was as high as 95 per cent. Carbon dioxide and Mn(II) recovery rates were 81 and 77 per cent respectively. Reactor sediment was withdrawn on day 104 and subject to DGGE profiling. This sediment showed different band patterns than the original sediment that was not exposed to benzene. The authors conclude that the species associated with the degradation of benzene are of the genus Propionibacterium and Actinomyces. 17 refs., 2 figs.
Anaerobic digestion of amine-oxide-based surfactants: biodegradation kinetics and inhibitory effects.

Science.gov (United States)

Ríos, Francisco; Lechuga, Manuela; Fernández-Arteaga, Alejandro; Jurado, Encarnación; Fernández-Serrano, Mercedes

2017-08-01

Recently, anaerobic degradation has become a prevalent alternative for the treatment of wastewater and activated sludge. Consequently, the anaerobic biodegradability of recalcitrant compounds such as some surfactants require a thorough study to avoid their presence in the environment. In this work, the anaerobic biodegradation of amine-oxide-based surfactants, which are toxic to several organisms, was studied by measuring of the biogas production in digested sludge. Three amine-oxide-based surfactants with structural differences in their hydrophobic alkyl chain were tested: Lauramine oxide (AO-R 12 ), Myristamine oxide (AO-R 14 ) and Cocamidopropylamine oxide (AO-cocoamido). Results show that AO-R 12 and AO-R 14 inhibit biogas production, inhibition percentages were around 90%. AO-cocoamido did not cause inhibition and it was biodegraded until reaching a percentage of 60.8%. Otherwise, we fitted the production of biogas to two kinetic models, to a pseudo first-order model and to a logistic model. Production of biogas during the anaerobic biodegradation of AO-cocoamido was pretty good adjusted to the logistics model. Kinetic parameters were also determined. This modelling is useful to predict their behaviour in wastewater treatment plants and under anaerobic conditions in the environment.
Potential of the aquatic fern Azolla filiculoides in biodegradation of an azo dye: modeling of experimental results by artificial neural networks.

Science.gov (United States)

Khataee, A R; Movafeghi, A; Vafaei, F; Lisar, S Y Salehi; Zarei, M

2013-01-01

The potential of an aquatic fern, Azolla filiculoides, in phytoremediation of a mono azo dye solution, C.I. Acid Blue 92 (AB92), was studied. The effects of operational parameters such as reaction time, initial dye concentration, fern fresh weight, pH, temperature and reusability of the fern on biodegradation efficiency were investigated. The intermediate compounds produced by biodegradation process were analyzed using GC-MS analysis. An artificial neural network (ANN) model was developed to predict the biodegradation efficiency. The findings indicated that ANN provides reasonable predictive performance (R2 = 0.961). The effects of AB92 solutions (10 and 20 mg L(-1)) on growth, chlorophylls and carotenoids content, activity of antioxidant enzymes such as superoxide dismutase, peroxidase and catalase and formation of malondialdehyde were analyzed. AB92 generally showed inhibitory effects on the growth. Moreover, photosynthetic pigments in the fronds significantly decreased in the treatments. An increase was detected for lipid peroxidation and antioxidant enzymes activity, suggesting that AB92 caused reactive oxygen species production in Azolla fronds, which were scavenged by induced activities of antioxidant enzymes.
Optimizing BTEX biodegradation under denitrifying conditions

International Nuclear Information System (INIS)

Hutchins, S.R.

1991-01-01

Leaking underground storage tanks are a major source of ground water contamination by petroleum hydrocarbons. Gasoline and other fuels contain benzene, toluene, ethylbenzene, and xylenes (collectively known as BTEX), which are hazardous compounds, regulated by the U.S. Environmental Protection Agency (EPA). Laboratory tests were conducted to determine optimum conditions for benzene, toluene, ethylbenzene, and xylene (collectively known as BTEX) biodegradation by aquifer microorganisms under denitrifying conditions. Microcosms, constructed with aquifer samples from Traverse City, Michigan, were amended with selected concentrations of nutrients and one or more hydrocarbons. Toluene, ethylbenzene, m-xylene, and p-xylene, were degraded to below 5 micrograms/L when present as sole source substrates; stoichiometric calculations indicated that nitrate removal was sufficient to account for 70 to 80% of the compounds being mineralized. o-Xylene was recalcitrant when present as a sole source substrate, but was slowly degraded in the presence of the other hydrocarbons. Benzene was not degraded within one year, regardless of whether it was available as a sole source substrate or in combination with toluene, phenol, or catechol. Pre-exposure to low levels of BTEX and nutrients had variable effects, as did the addition of different concentrations of ammonia and phosphate. Nitrate concentrations as high as 500 mg/L NO3-N were slightly inhibitory. These data indicate that nitrate-mediated biodegradation of BTEX at Traverse City can occur under a variety of environmental conditions with rates relatively independent of nutrient concentrations. However, the data reaffirm that benzene is recalcitrant under strictly anaerobic conditions in these samples
Biodegradable Piezoelectric Force Sensor.

Science.gov (United States)

Curry, Eli J; Ke, Kai; Chorsi, Meysam T; Wrobel, Kinga S; Miller, Albert N; Patel, Avi; Kim, Insoo; Feng, Jianlin; Yue, Lixia; Wu, Qian; Kuo, Chia-Ling; Lo, Kevin W-H; Laurencin, Cato T; Ilies, Horea; Purohit, Prashant K; Nguyen, Thanh D

2018-01-30

Measuring vital physiological pressures is important for monitoring health status, preventing the buildup of dangerous internal forces in impaired organs, and enabling novel approaches of using mechanical stimulation for tissue regeneration. Pressure sensors are often required to be implanted and directly integrated with native soft biological systems. Therefore, the devices should be flexible and at the same time biodegradable to avoid invasive removal surgery that can damage directly interfaced tissues. Despite recent achievements in degradable electronic devices, there is still a tremendous need to develop a force sensor which only relies on safe medical materials and requires no complex fabrication process to provide accurate information on important biophysiological forces. Here, we present a strategy for material processing, electromechanical analysis, device fabrication, and assessment of a piezoelectric Poly-l-lactide (PLLA) polymer to create a biodegradable, biocompatible piezoelectric force sensor, which only employs medical materials used commonly in Food and Drug Administration-approved implants, for the monitoring of biological forces. We show the sensor can precisely measure pressures in a wide range of 0-18 kPa and sustain a reliable performance for a period of 4 d in an aqueous environment. We also demonstrate this PLLA piezoelectric sensor can be implanted inside the abdominal cavity of a mouse to monitor the pressure of diaphragmatic contraction. This piezoelectric sensor offers an appealing alternative to present biodegradable electronic devices for the monitoring of intraorgan pressures. The sensor can be integrated with tissues and organs, forming self-sensing bionic systems to enable many exciting applications in regenerative medicine, drug delivery, and medical devices.
Evaluation of the biodegradation of Alaska North Slope oil in microcosms using the biodegradation model BIOB

Directory of Open Access Journals (Sweden)

Jagadish eTorlapati

2014-05-01

Full Text Available We present the details of a numerical model, BIOB that is capable of simulating the biodegradation of oil entrapped in the sediment. The model uses Monod kinetics to simulate the growth of bacteria in the presence of nutrients and the subsequent consumption of hydrocarbons. The model was used to simulate experimental results of Exxon Valdez oil biodegradation in laboratory columns (Venosa et al. (2010. In that study, samples were collected from three different islands: Eleanor Island (EL107, Knight Island (KN114A, and Smith Island (SM006B, and placed in laboratory microcosms for a duration of 168 days to investigate oil bioremediation through natural attenuation and nutrient amendment. The kinetic parameters of the BIOB model were estimated by fitting to the experimental data using a parameter estimation tool based on Genetic Algorithms (GA. The parameter values of EL107 and KN114A were similar whereas those of SM006B were different from the two other sites; in particular biomass growth at SM006B was four times slower than at the other two islands. Grain size analysis from each site revealed that the specific surface area per unit mass of sediment was considerably lower at SM006B, which suggest that the surface area of sediments is a key control parameter for microbial growth in sediments. Comparison of the BIOB results with exponential decay curves fitted to the data indicated that BIOB provided better fit for KN114A and SM006B in nutrient amended treatments, and for EL107 and KN114A in natural attenuation. In particular, BIOB was able to capture the initial slow biodegradation due to the lag phase in microbial growth. Sensitivity analyses revealed that oil biodegradation at all three locations were sensitive to nutrient concentration whereas SM006B was sensitive to initial biomass concentration due to its slow growth rate. Analyses were also performed to compare the half-lives of individual compounds with the decay rate of the overall PAH.
Degradation of cyclophosphamide and 5-fluorouracil by UV and simulated sunlight treatments: Assessment of the enhancement of the biodegradability and toxicity

International Nuclear Information System (INIS)

Lutterbeck, Carlos Alexandre; Wilde, Marcelo Luís; Baginska, Ewelina; Leder, Christoph; Machado, Ênio Leandro

2016-01-01

The presence of pharmaceuticals in the environment has triggered concern among the general population and received considerable attention from the scientific community in recent years. However, only a few publications have focused on anticancer drugs, a class of pharmaceuticals that can exhibit cytotoxic, genotoxic, mutagenic, carcinogenic and teratogenic effects. The present study investigated the photodegradation, biodegradation, bacterial toxicity, mutagenicity and genotoxicity of cyclophosphamide (CP) and 5-fluorouracil (5-FU). The photodegradation experiments were performed at a neutral to slight pH range (7–7.8) using two different lamps (medium-pressure mercury lamp and a xenon lamp). The primary elimination of the parent compounds was monitored by means of liquid chromatography tandem mass spectrometry (LC-IT-MS/MS). NPOC (non-purgeable organic carbon) analyses were carried out in order to assess mineralization rates. The Closed Bottle Test (CBT) was used to assess ready biodegradability. A new method using Vibrio fischeri was adopted to evaluate toxicity. CP was not degraded by any lamp, whereas 5-FU was completely eliminated by irradiation with the mercury lamp but only partially by the Xe lamp. No mineralization was observed for the experiments performed with the Xe lamp, and a NPOC removal of only 18% was registered for 5-FU after 256 min using the UV lamp. Not one of the parent compounds was readily biodegradable in the CBT. Photo transformation products (PTPs) resulting from photolysis were neither better biodegradable nor less toxic than the parent compound 5-FU. In contrast, the results of the tests carried out with the UV lamp indicated that more biodegradable and non-toxic PTPs of 5-FU were generated. Three PTPs were formed during the photodegradation experiments and were identified. The results of the in silico QSAR predictions showed positive mutagenic and genotoxic alerts for 5-FU, whereas only one of the formed PTPs presented positive
Biodegradable congress 2012; Bioschmierstoff-Kongress 2012

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-11-01

Within the Guelzower expert discussions at 5th and 6th June, 2012 in Oberhausen (Federal Republic of Germany) the following lectures were held: (1) Promotion of biodegradable lubricants by means of research and development as well as public relations (Steffen Daebeler); (2) Biodegradable lubricants - An overview of the advantages and disadvantages of the engaged product groups (Hubertus Murrenhoff); (3) Standardization of biodegradable lubricants - CEN/DIN standard committees - state of the art (Rolf Luther); (4) Market research for the utilization of biodegradable lubricants and means of proof of sustainability (Norbert Schmitz); (5) Fields of application for high performance lubricants and requirements upon the products (Gunther Kraft); (6) Investigations of biodegradable lubricants in rolling bearings and gears (Christoph Hentschke); (7) Biodegradable lubricants in central lubrication systems Development of gears and bearings of offshore wind power installations (Reiner Wagner); (8) Investigations towards environmental compatibility of biodegradable lubricants used in offshore wind power installations (Tolf Schneider); (9) Development of glycerine based lubricants for the industrial metalworking (Harald Draeger); (10) Investigations and utilization of biodegradable oils as electroinsulation oils in transformers (Stefan Tenbohlen); (11) Operational behaviour of lubricant oils in vegetable oil operation and Biodiesel operation (Horst Hamdorf); (12) Lubrication effect of lubricating oil of the third generation (Stefan Heitzig); (13) Actual market development from the view of a producer of biodegradable lubricants (Frank Lewen); (14) Utilization of biodegradable lubricants in forestry harvesters (Guenther Weise); (15) New biodegradable lubricants based on high oleic sunflower oil (Otto Botz); (16) Integrated fluid concept - optimized technology and service package for users of biodegradable lubricants (Juergen Baer); (17) Utilization of a bio oil sensor to control
Deciphering biodegradation effects on light hydrocarbons in crude oils using their stable carbon isotopic composition: a case study from the Gullfaks oil field, offshore Norway

OpenAIRE

Andrea Vieth-Hillebrand [Vieth; Heinz Wilkes

2006-01-01

Compound-specific isotope analysis has become an important tool in environmental studies and is an especially powerful way to evaluate biodegradation of hydrocarbons. Here, carbon isotope ratios of light hydrocarbons were used to characterise in-reservoir biodegradation in the Gullfaks oil field, offshore Norway. Increasing biodegradation, as characterised, for example, by increasing concentration ratios of Pr/n-C17 and Ph/n-C18, and decreasing concentrations of individual light hydrocarbons ...
Biodegradability of wheat gluten based bioplastics.

Science.gov (United States)

Domenek, Sandra; Feuilloley, Pierre; Gratraud, Jean; Morel, Marie-Hélène; Guilbert, Stéphane

2004-01-01

A large variety of wheat gluten based bioplastics, which were plasticized with glycerol, were subjected to biodegradation. The materials covered the total range available for the biochemical control parameter Fi, which expresses the percentage of aggregated proteins. This quantity can be related to the density of covalent crosslinks in the wheat gluten network, which are induced by technological treatments. The biodegradability tests were performed in liquid medium (modified Sturm test) and in farmland soil. All gluten materials were fully degraded after 36 days in aerobic fermentation and within 50 days in farmland soil. No significant differences were observed between the samples. The mineralization half-life time of 3.8 days in the modified Sturm test situated gluten materials among fast degrading polymers. The tests of microbial inhibition experiments revealed no toxic effects of the modified gluten or of its metabolites. Thus, the protein bulk of wheat gluten materials is non-toxic and fully biodegradable, whatever the technological process applied.
Biodegradation of sulfamethoxazole by individual and mixed bacteria.

Science.gov (United States)

Larcher, Simone; Yargeau, Viviane

2011-07-01

Antibiotic compounds, like sulfamethoxazole (SMX), have become a concern in the aquatic environment due to the potential development of antibacterial resistances. Due to excretion and disposal, SMX has been frequently detected in wastewaters and surface waters. SMX removal in conventional wastewater treatment plants (WWTPs) ranges from 0% to 90%, and there are opposing results regarding its biodegradability at lab scale. The objective of this research was to determine the ability of pure cultures of individual and mixed consortia of bacteria (Bacillus subtilis, Pseudomonas aeruginosa, Pseudomonas putida, Rhodococcus equi, Rhodococcus erythropolis, Rhodococcus rhodocrous, and Rhodococcus zopfii) known to exist in WWTP activated sludge to remove SMX. Results showed that R. equi alone had the greatest ability to remove SMX leading to 29% removal (with glucose) and the formation of a metabolite. Degradation pathways and metabolite structures have been proposed based on the potential enzymes produced by R. equi. When R. equi was mixed with other microorganisms, a positive synergistic effect was not observed and the maximum SMX removal achieved was 5%. This indicates that pure culture results cannot be extrapolated to mixed culture conditions, and the methodology developed here to study the biodegradability of compounds under controlled mixed culture conditions offers an alternative to conventional studies using pure bacterial cultures or inocula from activated sludge sources consisting of unknown and variable microbial populations.
Contribution of microorganisms to non-extractable residue formation during biodegradation of ibuprofen in soil

Energy Technology Data Exchange (ETDEWEB)

Nowak, Karolina M., E-mail: karolina.nowak@ufz.de [UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany); Department of Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Girardi, Cristobal; Miltner, Anja [UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany); Gehre, Matthias [UFZ, Helmholtz Centre for Environmental Research, Department of Isotope Biogeochemistry, Permoserstraße 15, 04318 Leipzig (Germany); Schäffer, Andreas [Department of Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Kästner, Matthias [UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig (Germany)

2013-02-15

Non-extractable residues (NER) formed during biodegradation of organic contaminants in soil are considered to be mainly composed of parent compounds or their primary metabolites with hazardous potential. However, in the case of biodegradable organic compounds, the soil NER may also contain microbial biomass components, for example fatty acids (FA) and amino acids (AA). After cell death, these biomolecules are subsequently incorporated into non-living soil organic matter (SOM) and are stabilised ultimately forming hardly extractable residues of biogenic origin. We investigated biodegradation of {sup 13}C{sub 6}-ibuprofen, in particular the metabolic incorporation of the {sup 13}C-label into FA and AA and their fate in soil over 90 days. {sup 13}C-FA and {sup 13}C-AA amounts in the living microbial biomass fraction initially increased, then decreased over time and were continuously incorporated into the non-living SOM pool. The {sup 13}C-FA in the non-living SOM remained stable from day 59 whereas the contents of {sup 13}C-AA slightly increased until the end. After 90 days, nearly all NER were biogenic as they were made up almost completely by natural biomass compounds. The presented data demonstrated that the potential environmental risks related to the ibuprofen-derived NER are overestimated. - Highlights: ► Biogenic residue formation during microbial degradation of ibuprofen was studied. ► Nearly all non-extractable residues derived from ibuprofen were biogenic. ► Fatty acids and amino acids formed biogenic non-extractable residues and were stabilised in soil. ► Environmental risks of ibuprofen-derived non-extractable residues are overestimated.
Contribution of microorganisms to non-extractable residue formation during biodegradation of ibuprofen in soil

International Nuclear Information System (INIS)

Nowak, Karolina M.; Girardi, Cristobal; Miltner, Anja; Gehre, Matthias; Schäffer, Andreas; Kästner, Matthias

2013-01-01

Non-extractable residues (NER) formed during biodegradation of organic contaminants in soil are considered to be mainly composed of parent compounds or their primary metabolites with hazardous potential. However, in the case of biodegradable organic compounds, the soil NER may also contain microbial biomass components, for example fatty acids (FA) and amino acids (AA). After cell death, these biomolecules are subsequently incorporated into non-living soil organic matter (SOM) and are stabilised ultimately forming hardly extractable residues of biogenic origin. We investigated biodegradation of 13 C 6 -ibuprofen, in particular the metabolic incorporation of the 13 C-label into FA and AA and their fate in soil over 90 days. 13 C-FA and 13 C-AA amounts in the living microbial biomass fraction initially increased, then decreased over time and were continuously incorporated into the non-living SOM pool. The 13 C-FA in the non-living SOM remained stable from day 59 whereas the contents of 13 C-AA slightly increased until the end. After 90 days, nearly all NER were biogenic as they were made up almost completely by natural biomass compounds. The presented data demonstrated that the potential environmental risks related to the ibuprofen-derived NER are overestimated. - Highlights: ► Biogenic residue formation during microbial degradation of ibuprofen was studied. ► Nearly all non-extractable residues derived from ibuprofen were biogenic. ► Fatty acids and amino acids formed biogenic non-extractable residues and were stabilised in soil. ► Environmental risks of ibuprofen-derived non-extractable residues are overestimated
Biodegradation of pharmaceuticals from hospital wastewater in staged Moving Bed Biofilm Reactors (MBBR)

DEFF Research Database (Denmark)

Escola, Monica; Kumar Chhetri, Ravi; Ooi, Gordon

2015-01-01

on biofilms that are grown on plastic-chips which are suspended and aerated in a treatment tank. Such biofilm systems have shown a clear (but slow) biodegradation of some compounds that are recalcitrant in activated sludge. This study investigated the performance of a pilot MBBR-plant for the removal...
Biodegradation of tetrabromobisphenol A in the sewage sludge process.

Science.gov (United States)

Peng, Xingxing; Wang, Zhangna; Wei, Dongyang; Huang, Qiyuan; Jia, Xiaoshan

2017-11-01

Anaerobic sewage sludge capable of rapidly degrading tetrabromobisphenol A (TBBPA) was successfully acclimated in an anaerobic reactor over 280days. During the period from 0 to 280days, the TBBPA degradation rate (DR), utilization of glucose, and VSS were monitored continuously. After 280days of acclimation, the TBBPA DR of active sludge reached 96.0% after 20days of treatment in batch experiments. Based on scanning electron microscopy (SEM) observations and denaturing gradient gel electrophoresis (DGGE) determinations, the diversity of the microorganisms after 0 and 280days in the acclimated anaerobic sewage sludge was compared. Furthermore, eleven metabolites, including 2-bromophenol, 3-bromophenol, 2,4-dibromophenol, 2,6-dibromophenol, tribromophenol and bisphenol A, were identified by gas chromatography-mass spectrometry (GC-MS). Moreover, the six primary intermediary metabolites were also well-degraded by the acclimated anaerobic sewage sludge to varying degrees. Among the six target metabolites, tribromophenol was the most preferred substrate for biodegradation via debromination. These metabolites degraded more rapidly than monobromide and bisphenol A. The biodegradation data of the intermediary metabolites exhibited a good fit to a pseudo-first-order model. Finally, based on the metabolites, metabolic pathways were proposed. In conclusion, the acclimated microbial consortia degraded TBBPA and its metabolites well under anaerobic conditions. Copyright © 2017. Published by Elsevier B.V.

Identifying model pollutants to investigate biodegradation of hazardous XOCs in WWTPs

Energy Technology Data Exchange (ETDEWEB)

Press-Kristensen, Kaare; Ledin, Anna; Schmidt, Jens Ejbye; Henze, Mogens [Department of Environment and Resources, Technical University of Denmark Building 115, 2800 Lyngby (Denmark)

2007-02-01

Xenobiotic organic compounds (XOCs) in wastewater treatment plant (WWTP) effluents might cause toxic effects in ecosystems. Several investigations have emphasized biodegradation as an important removal mechanism to reduce pollution with XOCs from WWTP effluents. The aim of the study was to design a screening tool to identify and select hazardous model pollutants for the further investigation of biodegradation in WWTPs. The screening tool consists of three criteria: The XOC is present in WWTP effluents, the XOC constitutes an intolerable risk in drinking water or the environment, and the XOC is expected to be biodegradable in WWTPs. The screening tool was tested on bisphenol A (BPA), carbamazepine (CBZ), di(2ethylhexyl)-phthalate (DEHP), 17{beta}-estradiol (E2), estrone (E1), 17{alpha}-ethinyloetradiol (EE2), ibuprofen, naproxen, nonylphenol (NP), and octylphenol (OP). BPA, DEHP, E2, E1, EE2, and NP passed all criteria in the screening tool and were selected as model pollutants. OP did not pass the filter and was rejected as model pollutant. CBZ, ibuprofen, and naproxen were not finally evaluated due to insufficient data. (author)
Best conditions for biodegradation of diesel oil by chemometric tools

Directory of Open Access Journals (Sweden)

Ewa Kaczorek

2014-01-01

Full Text Available Diesel oil biodegradation by different bacteria-yeast-rhamnolipids consortia was tested. Chromatographic analysis of post-biodegradation residue was completed with chemometric tools (ANOVA, and a novel ranking procedure based on the sum of ranking differences. These tools were used in the selection of the most effective systems. The best results of aliphatic fractions of diesel oil biodegradation were observed for a yeast consortia with Aeromonas hydrophila KR4. For these systems the positive effect of rhamnolipids on hydrocarbon biodegradation was observed. However, rhamnolipids addition did not always have a positive influence on the biodegradation process (e.g. in case of yeast consortia with Stenotrophomonas maltophila KR7. Moreover, particular differences in the degradation pattern were observed for lower and higher alkanes than in the case with C22. Normally, the best conditions for "lower" alkanes are Aeromonas hydrophila KR4 + emulsifier independently from yeasts and e.g. Pseudomonas stutzeri KR7 for C24 alkane.
Best conditions for biodegradation of diesel oil by chemometric tools

Science.gov (United States)

Kaczorek, Ewa; Bielicka-Daszkiewicz, Katarzyna; Héberger, Károly; Kemény, Sándor; Olszanowski, Andrzej; Voelkel, Adam

2014-01-01

Diesel oil biodegradation by different bacteria-yeast-rhamnolipids consortia was tested. Chromatographic analysis of post-biodegradation residue was completed with chemometric tools (ANOVA, and a novel ranking procedure based on the sum of ranking differences). These tools were used in the selection of the most effective systems. The best results of aliphatic fractions of diesel oil biodegradation were observed for a yeast consortia with Aeromonas hydrophila KR4. For these systems the positive effect of rhamnolipids on hydrocarbon biodegradation was observed. However, rhamnolipids addition did not always have a positive influence on the biodegradation process (e.g. in case of yeast consortia with Stenotrophomonas maltophila KR7). Moreover, particular differences in the degradation pattern were observed for lower and higher alkanes than in the case with C22. Normally, the best conditions for “lower” alkanes are Aeromonas hydrophila KR4 + emulsifier independently from yeasts and e.g. Pseudomonas stutzeri KR7 for C24 alkane. PMID:24948922
Microorganisms hydrolyse amide bonds; knowledge enabling read-across of biodegradability of fatty acid amides

NARCIS (Netherlands)

Geerts, R.; Kuijer, P.; Ginkel, van C.G.; Plugge, C.M.

2014-01-01

To get insight in the biodegradation and potential read-across of fatty acid amides, N-[3-(dimethylamino)propyl] cocoamide and N-(1-ethylpiperazine) tall oil amide were used as model compounds. Two bacteria, Pseudomonas aeruginosa PK1 and Pseudomonas putida PK2 were isolated with
External validation of structure-biodegradation relationship (SBR) models for predicting the biodegradability of xenobiotics.

Science.gov (United States)

Devillers, J; Pandard, P; Richard, B

2013-01-01

Biodegradation is an important mechanism for eliminating xenobiotics by biotransforming them into simple organic and inorganic products. Faced with the ever growing number of chemicals available on the market, structure-biodegradation relationship (SBR) and quantitative structure-biodegradation relationship (QSBR) models are increasingly used as surrogates of the biodegradation tests. Such models have great potential for a quick and cheap estimation of the biodegradation potential of chemicals. The Estimation Programs Interface (EPI) Suite™ includes different models for predicting the potential aerobic biodegradability of organic substances. They are based on different endpoints, methodologies and/or statistical approaches. Among them, Biowin 5 and 6 appeared the most robust, being derived from the largest biodegradation database with results obtained only from the Ministry of International Trade and Industry (MITI) test. The aim of this study was to assess the predictive performances of these two models from a set of 356 chemicals extracted from notification dossiers including compatible biodegradation data. Another set of molecules with no more than four carbon atoms and substituted by various heteroatoms and/or functional groups was also embodied in the validation exercise. Comparisons were made with the predictions obtained with START (Structural Alerts for Reactivity in Toxtree). Biowin 5 and Biowin 6 gave satisfactorily prediction results except for the prediction of readily degradable chemicals. A consensus model built with Biowin 1 allowed the diminution of this tendency.
Aerobic biodegradation potential of endocrine-disrupting chemicals in surface-water sediment at Rocky Mountain National Park, USA.

Science.gov (United States)

Bradley, Paul M; Battaglin, William A; Iwanowicz, Luke R; Clark, Jimmy M; Journey, Celeste A

2016-05-01

Endocrine-disrupting chemicals (EDCs) in surface water and bed sediment threaten the structure and function of aquatic ecosystems. In natural, remote, and protected surface-water environments where contaminant releases are sporadic, contaminant biodegradation is a fundamental driver of exposure concentration, timing, duration, and, thus, EDC ecological risk. Anthropogenic contaminants, including known and suspected EDCs, were detected in surface water and sediment collected from 2 streams and 2 lakes in Rocky Mountain National Park (Colorado, USA). The potential for aerobic EDC biodegradation was assessed in collected sediments using 6 (14) C-radiolabeled model compounds. Aerobic microbial mineralization of natural (estrone and 17β-estradiol) and synthetic (17α-ethinylestradiol) estrogen was significant at all sites. Bed sediment microbial communities in Rocky Mountain National Park also effectively degraded the xenoestrogens bisphenol-A and 4-nonylphenol. The same sediment samples exhibited little potential for aerobic biodegradation of triclocarban, however, illustrating the need to assess a wider range of contaminant compounds. The present study's results support recent concerns over the widespread environmental occurrence of carbanalide antibacterials, like triclocarban and triclosan, and suggest that backcountry use of products containing these compounds should be discouraged. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.
Biosorption and biodegradation of a sulfur dye in high-strength dyeing wastewater by Acidithiobacillus thiooxidans.

Science.gov (United States)

Nguyen, Thai Anh; Fu, Chun-Chieh; Juang, Ruey-Shin

2016-11-01

The ability of the bacterial strain Acidithiobacillus thiooxidans to remove sulfur blue 15 (SB15) dye from water samples was examined. This bacterium could not only oxidize sulfur compounds to sulfuric acid but also promote the attachment of the cells to the surface of sulfidic particles, therefore serving as an efficient biosorbent. The biosorption isotherms were better described by the Langmuir equation than by the Freundlich or Dubinin-Radushkevich equation. Also, the biosorption process followed the pseudo-second-order kinetics. At pH 8.3 and SB15 concentrations up to 2000 mg L(-1) in the biomass/mineral salt solution, the dye removal and decolorization were 87.5% and 91.4%, respectively, following the biosorption process. Biodegradation was proposed as a subsequent process for the remaining dye (250-350 mg L(-1)). A central composite design was used to analyze independent variables in the response surface methodology study. Under the optimal conditions (i.e., initial dye concentration of 300 mg L(-1), initial biomass concentration of 1.0 g L(-1), initial pH of 11.7, and yeast extract dose of 60 mg L(-1)), up to 50% of SB15 was removed after 4 days of biodegradation. Copyright © 2016 Elsevier Ltd. All rights reserved.
From organic pollutants to bioplastics: insights into the bioremediation of aromatic compounds by Cupriavidus necator.

Science.gov (United States)

Berezina, Nathalie; Yada, Bopha; Lefebvre, Rodrigue

2015-01-25

Organic pollution by aromatic compounds is of increasing concern to our environment. Therefore, the transformation of aromatic pollutants into valuable aliphatic and biodegradable bioplastics was studied. Since benzoic acid was found to be the key compound for such bioremediation processes, its transformation, and metabolic pathways of digestion, by Cupriavidus necator were specifically analysed. It was found that the degradation of aromatic compounds follows the 2,3-dioxygenase pathway in this strain and that the batch transformations of benzoic acid with either fresh or adapted cells were limited to an initial concentration of 2.5 g/L of pollutant. The repeated fed-batch with partial withdrawal process, however, showed a 17.5-fold improvement, thus allowing the transformation of a total of 43.7 g/L in 12 weeks. Copyright © 2014 Elsevier B.V. All rights reserved.
MICROBIAL DEGRADATION OF NITROGEN, OXYGEN AND SULFUR HETEROCYCLIC COMPOUNDS UNDER ANAEROBIC CONDITIONS: STUDIES WITH AQUIFER SAMPLES

Science.gov (United States)

The potential for anaerobic biodegradation of 12 heterocyclic model compounds was studied. Nine of the model compounds were biotransformed in aquifer slurries under sulfate-reducing or methanogenic conditions. The nitrogen and oxygen heterocyclic compounds were more susceptible t...
Biodegradation of tributyl phosphate, an organosphate triester, by aerobic granular biofilms

Energy Technology Data Exchange (ETDEWEB)

Nancharaiah, Y.V., E-mail: venkatany@gmail.com; Kiran Kumar Reddy, G.; Krishna Mohan, T.V.; Venugopalan, V.P.

2015-02-11

Graphical abstract: - Highlights: • Aerobic granular biomass was cultivated by feeding TBP along with acetate. • Rapid biodegradation of TBP when used as a co-substrate or as the sole carbon source. • Biodegradation of 2 mM TBP in 5 h with degradation rate of 0.4 μmol mL{sup −1} h{sup −1}. • High phosphatase activity was observed in TBP-degrading granular biomass. • n-Butanol, hydrolyzed product of TBP, was rapidly metabolized by aerobic granules. - Abstract: Tributyl phosphate (TBP) is commercially used in large volumes for reprocessing of spent nuclear fuel. TBP is a very stable compound and persistent in natural environments and it is not removed in conventional wastewater treatment plants. In this study, cultivation of aerobic granular biofilms in a sequencing batch reactor was investigated for efficient biodegradation of TBP. Enrichment of TBP-degrading strains resulted in efficient degradation of TBP as sole carbon or along with acetate. Complete biodegradation of 2 mM of TBP was achieved within 5 h with a degradation rate of 0.4 μmol mL{sup −1} h{sup −1}. TBP biodegradation was accompanied by release of inorganic phosphate in stoichiometric amounts. n-Butanol, hydrolysed product of TBP was rapidly biodegraded. But, dibutyl phosphate, a putative intermediate of TBP degradation was only partially degraded pointing to an alternative degradation pathway. Phosphatase activity was 22- and 7.5-fold higher in TBP-degrading biofilms as compared to bioflocs and acetate-fed aerobic granules. Community analysis by terminal restriction length polymorphism revealed presence of 30 different bacterial strains. Seven bacterial stains, including Sphingobium sp. a known TBP degrader were isolated. The results show that aerobic granular biofilms are promising for treatment of TBP-bearing wastes or ex situ bioremediation of TBP-contaminated sites.
Biodegradation of tributyl phosphate, an organosphate triester, by aerobic granular biofilms

International Nuclear Information System (INIS)

Nancharaiah, Y.V.; Kiran Kumar Reddy, G.; Krishna Mohan, T.V.; Venugopalan, V.P.

2015-01-01

Graphical abstract: - Highlights: • Aerobic granular biomass was cultivated by feeding TBP along with acetate. • Rapid biodegradation of TBP when used as a co-substrate or as the sole carbon source. • Biodegradation of 2 mM TBP in 5 h with degradation rate of 0.4 μmol mL −1 h −1 . • High phosphatase activity was observed in TBP-degrading granular biomass. • n-Butanol, hydrolyzed product of TBP, was rapidly metabolized by aerobic granules. - Abstract: Tributyl phosphate (TBP) is commercially used in large volumes for reprocessing of spent nuclear fuel. TBP is a very stable compound and persistent in natural environments and it is not removed in conventional wastewater treatment plants. In this study, cultivation of aerobic granular biofilms in a sequencing batch reactor was investigated for efficient biodegradation of TBP. Enrichment of TBP-degrading strains resulted in efficient degradation of TBP as sole carbon or along with acetate. Complete biodegradation of 2 mM of TBP was achieved within 5 h with a degradation rate of 0.4 μmol mL −1 h −1 . TBP biodegradation was accompanied by release of inorganic phosphate in stoichiometric amounts. n-Butanol, hydrolysed product of TBP was rapidly biodegraded. But, dibutyl phosphate, a putative intermediate of TBP degradation was only partially degraded pointing to an alternative degradation pathway. Phosphatase activity was 22- and 7.5-fold higher in TBP-degrading biofilms as compared to bioflocs and acetate-fed aerobic granules. Community analysis by terminal restriction length polymorphism revealed presence of 30 different bacterial strains. Seven bacterial stains, including Sphingobium sp. a known TBP degrader were isolated. The results show that aerobic granular biofilms are promising for treatment of TBP-bearing wastes or ex situ bioremediation of TBP-contaminated sites
Stable carbon isotope fractionation during the biodegradation of lambda-cyhalothrin.

Science.gov (United States)

Shen, Xiaoli; Xu, Zemin; Zhang, Xichang; Yang, Fangxing

2015-11-01

In this study, the microbial degradation of lambda-cyhalothrin in soil was investigated using compound-specific stable isotope analysis. The results revealed that lambda-cyhalothrin was biodegraded in soil under laboratory conditions. The half-lives of lambda-cyhalothrin were determined to be 49 and 161 days in non-sterile and sterile soils spiked with 2mg/kg lambda-cyhalothrin and 84 and 154 days in non-sterile and sterile soils spiked with 10mg/kg lambda-cyhalothrin, respectively. The biodegradation of lambda-cyhalothrin resulted in carbon isotope fractionation, which shifted from -29.0‰ to -26.5‰ in soil spiked with 2mg/kg lambda-cyhalothrin, and to -27.5‰ with 10mg/kg lambda-cyhalothrin. A relationship was established between the stable carbon isotope fraction and the residual concentrations of lambda-cyhalothrin by the Rayleigh equation in which the carbon isotope enrichment factor ε of the microbial degradation of lambda-cyhalothrin in the soil was calculated as -2.53‰. This study provides an approach to quantitatively evaluate the biodegradation of lambda-cyhalothrin in soil in field studies. Copyright © 2015 Elsevier B.V. All rights reserved.
Current trends in biodegradable polyhydroxyalkanoates.

Science.gov (United States)

Chanprateep, Suchada

2010-12-01

The microbial polyesters known as polyhydroxyalkanoates (PHAs) positively impact global climate change scenarios by reducing the amount of non-degradable plastic used. A wide variety of different monomer compositions of PHAs has been described, as well as their future prospects for applications where high biodegradability or biocompatibility is required. PHAs can be produced from renewable raw materials and are degraded naturally by microorganisms that enable carbon dioxide and organic compound recycling in the ecosystem, providing a buffer to climate change. This review summarizes recent research on PHAs and addresses the opportunities as well as challenges for their place in the global market. Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
Alternative Forms of Compound Fractional Poisson Processes

Directory of Open Access Journals (Sweden)

Luisa Beghin

2012-01-01

Full Text Available We study here different fractional versions of the compound Poisson process. The fractionality is introduced in the counting process representing the number of jumps as well as in the density of the jumps themselves. The corresponding distributions are obtained explicitly and proved to be solution of fractional equations of order less than one. Only in the final case treated in this paper, where the number of jumps is given by the fractional-difference Poisson process defined in Orsingher and Polito (2012, we have a fractional driving equation, with respect to the time argument, with order greater than one. Moreover, in this case, the compound Poisson process is Markovian and this is also true for the corresponding limiting process. All the processes considered here are proved to be compositions of continuous time random walks with stable processes (or inverse stable subordinators. These subordinating relationships hold, not only in the limit, but also in the finite domain. In some cases the densities satisfy master equations which are the fractional analogues of the well-known Kolmogorov one.
Transformation and biodegradation of 1,2,3-trichloropropane (TCP).

Science.gov (United States)

Samin, Ghufrana; Janssen, Dick B

2012-09-01

1,2,3-Trichloropropane (TCP) is a persistent groundwater pollutant and a suspected human carcinogen. It is also is an industrial chemical waste that has been formed in large amounts during epichlorohydrin manufacture. In view of the spread of TCP via groundwater and its toxicity, there is a need for cheap and efficient technologies for the cleanup of TCP-contaminated sites. In situ or on-site bioremediation of TCP is an option if biodegradation can be achieved and stimulated. This paper presents an overview of methods for the remediation of TCP-contaminated water with an emphasis on the possibilities of biodegradation. Although TCP is a xenobiotic chlorinated compound of high chemical stability, a number of abiotic and biotic conversions have been demonstrated, including abiotic oxidative conversion in the presence of a strong oxidant and reductive conversion by zero-valent zinc. Biotransformations that have been observed include reductive dechlorination, monooxygenase-mediated cometabolism, and enzymatic hydrolysis. No natural organisms are known that can use TCP as a carbon source for growth under aerobic conditions, but anaerobically TCP may serve as electron acceptor. The application of biodegradation is hindered by low degradation rates and incomplete mineralization. Protein engineering and genetic modification can be used to obtain microorganisms with enhanced TCP degradation potential.
Anaerobic biodegradability and methanogenic toxicity of key constituents in copper chemical mechanical planarization effluents of the semiconductor industry.

Science.gov (United States)

Hollingsworth, Jeremy; Sierra-Alvarez, Reyes; Zhou, Michael; Ogden, Kimberly L; Field, Jim A

2005-06-01

Copper chemical mechanical planarization (CMP) effluents can account for 30-40% of the water discharge in semiconductor manufacturing. CMP effluents contain high concentrations of soluble copper and a complex mixture of organic constituents. The aim of this study is to perform a preliminary assessment of the treatability of CMP effluents in anaerobic sulfidogenic bioreactors inoculated with anaerobic granular sludge by testing individual compounds expected in the CMP effluents. Of all the compounds tested (copper (II), benzotriazoles, polyethylene glycol (M(n) 300), polyethylene glycol (M(n) 860) monooleate, perfluoro-1-octane sulfonate, citric acid, oxalic acid and isopropanol) only copper was found to be inhibitory to methanogenic activity at the concentrations tested. Most of the organic compounds tested were biodegradable with the exception of perfluoro-1-octane sulfonate and benzotriazoles under sulfate reducing conditions and with the exception of the same compounds as well as Triton X-100 under methanogenic conditions. The susceptibility of key components in CMP effluents to anaerobic biodegradation combined with their low microbial inhibition suggest that CMP effluents should be amenable to biological treatment in sulfate reducing bioreactors.
Comparative study on the biodegradation and biocompatibility of silicate bioceramic coatings on biodegradable magnesium alloy as biodegradable biomaterial

Science.gov (United States)

Razavi, M.; Fathi, M. H.; Savabi, O.; Razavi, S. M.; Hashemibeni, B.; Yazdimamaghani, M.; Vashaee, D.; Tayebi, L.

2014-03-01

Many clinical cases as well as in vivo and in vitro assessments have demonstrated that magnesium alloys possess good biocompatibility. Unfortunately, magnesium and its alloys degrade too quickly in physiological media. In order to improve the biodegradation resistance and biocompatibility of a biodegradable magnesium alloy, we have prepared three types of coating include diopside (CaMgSi2O6), akermanite (Ca2MgSi2O6) and bredigite (Ca7MgSi4O16) coating on AZ91 magnesium alloy through a micro-arc oxidation (MAO) and electrophoretic deposition (EPD) method. In this research, the biodegradation and biocompatibility behavior of samples were evaluated in vitro and in vivo. The in vitro analysis was performed by cytocompatibility and MTT-assay and the in vivo test was conducted on the implantation of samples in the greater trochanter of adult rabbits. The results showed that diopside coating has the best bone regeneration and bredigite has the best biodegradation resistance compared to others.
Use Of Biodegradation Ratios In Monitoring Trend Of Biostimulated Biodegradation In Crude Oil Polluted Soils

Directory of Open Access Journals (Sweden)

Okorondu

2017-03-01

Full Text Available This study deals with biodegradation experiment on soil contaminated with crude oil. The soil sample sets A BC D E F G were amended with inorganic fertilizer to enhance microbial growth and hydrocarbon degradation moisture content of some of the sets were as well varied. Biodegradation ratios nC17Pr nC18Ph and nC17nC18PrPh were used to monitor biodegradation of soil sets A BC D E F G for a period of 180. The soil samples were each contaminated with the same amount of crude oil and exposed to specific substrate treatment regarding the amount of nutrients and water content over the same period of time. The trend in biodegradation of the different soil sample sets shows that biodegradation ratio nC17nC18PrPh was more reflective of and explains the biodegradation trend in all the sample sets throughout the period of the experiment hence a better parameter ratio for monitoring trend of biostimulated biodegradation. The order of preference of the biodegradation ratios is expressed as nC18Ph nC17Pr nC17nC18 PrPh. This can be a relevant support tool when designing bioremediation plan on field.
Sorption and biodegradation characteristics of the selected pharmaceuticals and personal care products onto tropical soil.

Science.gov (United States)

Foolad, Mahsa; Hu, Jiangyong; Tran, Ngoc Han; Ong, Say Leong

2016-01-01

In the present study, the sorption and biodegradation characteristics of five pharmaceutical and personal care products (PPCPs), including acetaminophen (ACT), carbamazepine (CBZ), crotamiton (CTMT), diethyltoluamide (DEET) and salicylic acid (SA), were studied in laboratory-batch experiments. Sorption kinetics experimental data showed that sorption systems under this study were more appropriately described by the pseudo second-order kinetics with a correlation coefficient (R2)>0.98. Sorption equilibrium data of almost all target compounds onto soil could be better described by the Freundlich sorption isotherm model. The adsorption results showed higher soil affinity for SA, following by ACT. Results also indicated a slight effect of pH on PPCP adsorption with lower pH causing lower adsorption of compounds onto the soil except for SA at pH 12. Moreover, adsorption of PPCPs onto the soil was influenced by natural organic matter (NOM) since the higher amount of NOM caused lower adsorption to the soil. Biodegradation studies of selected PPCPs by indigenous microbial community present in soil appeared that the removal rates of ACT, SA and DEET increased with time while no effect had been observed for the rest. This study suggests that the CBZ and CTMT can be considered as suitable chemical sewage indicators based on their low sorption affinity and high resistance to biodegradation.
Multivariate fractional Poisson processes and compound sums

OpenAIRE

Beghin, Luisa; Macci, Claudio

2015-01-01

In this paper we present multivariate space-time fractional Poisson processes by considering common random time-changes of a (finite-dimensional) vector of independent classical (non-fractional) Poisson processes. In some cases we also consider compound processes. We obtain some equations in terms of some suitable fractional derivatives and fractional difference operators, which provides the extension of known equations for the univariate processes.

Biodegradation of radioactive organic liquid waste from spent fuel reprocessing; Biodegradacao de rejeitos radioativos liquidos organicos provenientes do reprocessamento do combustivel nuclear

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Rafael Vicente de Padua

2008-07-01

The research and development program in reprocessing of low burn-up spent fuel elements began in Brazil in 70's, originating the lab-scale hot cell, known as Celeste located at Nuclear and Energy Research Institute, IPEN - CNEN/SP. The program was ended at the beginning of 90's, and the laboratory was closed down. Part of the radioactive waste generated mainly from the analytical laboratories is stored waiting for treatment at the Waste Management Laboratory, and it is constituted by mixture of aqueous and organic phases. The most widely used technique for the treatment of radioactive liquid wastes is the solidification in cement matrix, due to the low processing costs and compatibility with a wide variety of wastes. However, organics are generally incompatible with cement, interfering with the hydration and setting processes, and requiring pre -treatment with special additives to stabilize or destroy them. The objective of this work can be divided in three parts: organic compounds characterization in the radioactive liquid waste; the occurrence of bacterial consortia from Pocos de Caldas uranium mine soil and Sao Sebastiao estuary sediments that are able to degrade organic compounds; and the development of a methodology to biodegrade organic compounds from the radioactive liquid waste aiming the cementation. From the characterization analysis, TBP and ethyl acetate were chosen to be degraded. The results showed that selected bacterial consortia were efficient for the organic liquid wastes degradation. At the end of the experiments the biodegradation level were 66% for ethyl acetate and 70% for the TBP. (author)
Phthalates biodegradation in the environment.

Science.gov (United States)

Liang, Da-Wei; Zhang, Tong; Fang, Herbert H P; He, Jianzhong

2008-08-01

Phthalates are synthesized in massive amounts to produce various plastics and have become widespread in environments following their release as a result of extensive usage and production. This has been of an environmental concern because phthalates are hepatotoxic, teratogenic, and carcinogenic by nature. Numerous studies indicated that phthalates can be degraded by bacteria and fungi under aerobic, anoxic, and anaerobic conditions. This paper gives a review on the biodegradation of phthalates and includes the following aspects: (1) the relationship between the chemical structure of phthalates and their biodegradability, (2) the biodegradation of phthalates by pure/mixed cultures, (3) the biodegradation of phthalates under various environments, and (4) the biodegradation pathways of phthalates.
A review of plastic waste biodegradation.

Science.gov (United States)

Zheng, Ying; Yanful, Ernest K; Bassi, Amarjeet S

2005-01-01

With more and more plastics being employed in human lives and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. This review looks at the technological advancement made in the development of more easily biodegradable plastics and the biodegradation of conventional plastics by microorganisms. Additives, such as pro-oxidants and starch, are applied in synthetic materials to modify and make plastics biodegradable. Recent research has shown that thermoplastics derived from polyolefins, traditionally considered resistant to biodegradation in ambient environment, are biodegraded following photo-degradation and chemical degradation. Thermoset plastics, such as aliphatic polyester and polyester polyurethane, are easily attacked by microorganisms directly because of the potential hydrolytic cleavage of ester or urethane bonds in their structures. Some microorganisms have been isolated to utilize polyurethane as a sole source of carbon and nitrogen source. Aliphatic-aromatic copolyesters have active commercial applications because of their good mechanical properties and biodegradability. Reviewing published and ongoing studies on plastic biodegradation, this paper attempts to make conclusions on potentially viable methods to reduce impacts of plastic waste on the environment.
Effect of bicarbonate on biodegradation behaviour of pure magnesium in a simulated body fluid

International Nuclear Information System (INIS)

Li, Zaichun; Song, Guang-Ling; Song, Shizhe

2014-01-01

The effect of bicarbonate on biodegradation of pure magnesium in a simulated body fluid is investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, polarization curve and electrochemical impedance spectroscopy. The results show that magnesium biodegrades rapidly and non-uniformly during 27 h of immersion in four simulated body fluid solutions containing different concentrations of bicarbonate. The biodegradation rate first decreases and then increases with time. A small amount of bicarbonate in simulated body fluid has an inhibition effect on the Mg dissolution, while an overdose of bicarbonate addition activates the magnesium surface in the simulated body fluid. The interesting phenomena can be interpreted by a surface film model involving precipitation of calcium carbonate and further ionization of bicarbonate in the simulated body fluids, incorporation of calcium, carbonate and phosphate compounds in the surface film, and development of chloride-induced pitting corrosion damage on the magnesium with time
Lipase biocatalysis for useful biodegradable products

Energy Technology Data Exchange (ETDEWEB)

Linko, Y Y; Wang, Zhuo Lin; Uosukainen, E; Seppaelae, J [Helsinki Univ. of Technology, Espoo (Finland); Laemsae, M [Raisio Group Oil Milling Industry, Raisio (Finland)

1997-12-31

It was shown that lipases can be used as biocatalysts in the production of useful biodegradable compounds such as 1-butyl oleate by direct esterification of butanol and oleic acid to decrease viscosity of biodiesel in winter use. By enzymic transesterification, a mixture of 2-ethyl-1-hexyl esters from rapeseed oil fatty acids can be obtained in good yields for use as a solvent, and of trimethylolpropane esters for use as a lubricant. Finally, it was demonstrated that polyesters with a mass average molar mass in excess of 75,000 g mol{sup -}1 can be obtained by esterification or transesterification by using lipase as biocatalyst. (author) (3 refs.)
Lipase biocatalysis for useful biodegradable products

Energy Technology Data Exchange (ETDEWEB)

Linko, Y.Y.; Wang, Zhuo Lin; Uosukainen, E.; Seppaelae, J. [Helsinki Univ. of Technology, Espoo (Finland); Laemsae, M. [Raisio Group Oil Milling Industry, Raisio (Finland)

1996-12-31

It was shown that lipases can be used as biocatalysts in the production of useful biodegradable compounds such as 1-butyl oleate by direct esterification of butanol and oleic acid to decrease viscosity of biodiesel in winter use. By enzymic transesterification, a mixture of 2-ethyl-1-hexyl esters from rapeseed oil fatty acids can be obtained in good yields for use as a solvent, and of trimethylolpropane esters for use as a lubricant. Finally, it was demonstrated that polyesters with a mass average molar mass in excess of 75,000 g mol{sup -}1 can be obtained by esterification or transesterification by using lipase as biocatalyst. (author) (3 refs.)
Biodegradation of uranium-contaminated waste oil

International Nuclear Information System (INIS)

Hary, L.F.

1983-01-01

The Portsmouth Gaseous Diffusion Plant routinely generates quantities of uranium-contaminated waste oil. The current generation rate of waste oil is approximately 2000 gallons per year. The waste is presently biodegraded by landfarming on open field soil plots. However, due to the environmental concerns associated with this treatment process, studies were conducted to determine the optimum biodegradation conditions required for the destruction of this waste. Tests using respirometric flasks were conducted to determine the biodegradation rate for various types of Portsmouth waste oil. These tests were performed at three different loading rates, and on unfertilized and fertilized soil. Additional studies were conducted to evaluate the effectiveness of open field landfarming versus treatment at a greenhouse-like enclosure for the purpose of maintaining soil temperatures above ambient conditions. The respirometric tests concluded that the optimum waste oil loading rate is 10% weight of oil-carbon/weight of soil (30,600 gallons of uranium-contaminated waste oil/acre) on soils with adjusted carbon:nitrogen and carbon:phosphorus ratios of 60:1 and 800:1, respectively. Also, calculational results indicated that greenhouse technology does not provide a significant increase in biodegradation efficiency. Based on these study results, a 6300 ft. 2 abandoned anaerobic digester sludge drying bed is being modified into a permanent waste oil biodegradation facility. The advantage of using this area is that uranium contamination will be contained by the bed's existing leachate collection system. This modified facility will be capable of handling approximately 4500 gallons of waste oil per year; accordingly current waste generation quantities will be satisfactorily treated. 15 refs., 14 figs., 4 tabs
Hydrocarbons biodegradation in unsaturated porous medium

International Nuclear Information System (INIS)

Gautier, C.

2007-12-01

Biological processes are expected to play an important role in the degradation of petroleum hydrocarbons in contaminated soils. However, factors influencing the kinetics of biodegradation are still not well known, especially in the unsaturated zone. To address these biodegradation questions in the unsaturated zone an innovative experimental set up based on a physical column model was developed. This experimental set up appeared to be an excellent tool for elaboration of a structured porous medium, with well defined porous network and adjusted water/oil saturations. Homogeneous repartition of both liquid phases (i.e., aqueous and non aqueous) in the soil pores, which also contain air, was achieved using ceramic membranes placed at the bottom of the soil column. Reproducible interfaces (and connectivity) are developed between gas, and both non mobile water and NAPL phases, depending on the above-defined characteristics of the porous media and on the partial saturations of these three phases (NAPL, water and gas). A respirometric apparatus was coupled to the column. Such experimental set up have been validated with hexadecane in dilution in an HMN phase. This approach allowed detailed information concerning n-hexadecane biodegradation, in aerobic condition, through the profile of the oxygen consumption rate. We have taken benefit of this technique, varying experimental conditions, to determine the main parameters influencing the biodegradation kinetics and compositional evolution of hydrocarbons, under steady state unsaturated conditions and with respect to aerobic metabolism. Impacts of the nitrogen quantity and of three different grain sizes have been examined. Biodegradation of petroleum cut, as diesel cut and middle distillate without aromatic fraction, were, also studied. (author)
Biodegradative Activities of Selected Environmental Fungi on a Polyester Polyurethane Varnish and Polyether Polyurethane Foams.

Science.gov (United States)

Álvarez-Barragán, Joyce; Domínguez-Malfavón, Lilianha; Vargas-Suárez, Martín; González-Hernández, Ricardo; Aguilar-Osorio, Guillermo; Loza-Tavera, Herminia

2016-09-01

Polyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it is slowly degraded, there are limited recycling processes, and its destruction may generate toxic compounds. In this work, we isolated fungal strains able to grow in mineral medium with a polyester PU (PS-PU; Impranil DLN) or a polyether PU (PE-PU; Poly Lack) varnish as the only carbon source. Of the eight best Impranil-degrading strains, the six best degraders belonged to the Cladosporium cladosporioides complex, including the species C. pseudocladosporioides, C. tenuissimum, C. asperulatum, and C. montecillanum, and the two others were identified as Aspergillus fumigatus and Penicillium chrysogenum The best Impranil degrader, C. pseudocladosporioides strain T1.PL.1, degraded up to 87% after 14 days of incubation. Fourier transform infrared (FTIR) spectroscopy analysis of Impranil degradation by this strain showed a loss of carbonyl groups (1,729 cm(-1)) and N-H bonds (1,540 and 1,261 cm(-1)), and gas chromatography-mass spectrometry (GC-MS) analysis showed a decrease in ester compounds and increase in alcohols and hexane diisocyanate, indicating the hydrolysis of ester and urethane bonds. Extracellular esterase and low urease, but not protease activities were detected at 7 and 14 days of culture in Impranil. The best eight Impranil-degrading fungi were also able to degrade solid foams of the highly recalcitrant PE-PU type to different extents, with the highest levels generating up to 65% of dry-weight losses not previously reported. Scanning electron microscopy (SEM) analysis of fungus-treated foams showed melted and thinner cell wall structures than the non-fungus-treated ones, demonstrating fungal biodegradative action on PE-PU. Polyurethane waste disposal has become a serious problem. In this work, fungal strains able to efficiently degrade different types of polyurethanes are reported, and
Biodegradation of polycyclic aromatic hydrocarbons: Using microbial bioelectrochemical systems to overcome an impasse.

Science.gov (United States)

Kronenberg, Maria; Trably, Eric; Bernet, Nicolas; Patureau, Dominique

2017-12-01

Polycyclic aromatic hydrocarbons (PAHs) are hardly biodegradable carcinogenic organic compounds. Bioremediation is a commonly used method for treating PAH contaminated environments such as soils, sediment, water bodies and wastewater. However, bioremediation has various drawbacks including the low abundance, diversity and activity of indigenous hydrocarbon degrading bacteria, their slow growth rates and especially a limited bioavailability of PAHs in the aqueous phase. Addition of nutrients, electron acceptors or co-substrates to enhance indigenous microbial activity is costly and added chemicals often diffuse away from the target compound, thus pointing out an impasse for the bioremediation of PAHs. A promising solution is the adoption of bioelectrochemical systems. They guarantee a permanent electron supply and withdrawal for microorganisms, thereby circumventing the traditional shortcomings of bioremediation. These systems combine biological treatment with electrochemical oxidation/reduction by supplying an anode and a cathode that serve as an electron exchange facility for the biocatalyst. Here, recent achievements in polycyclic aromatic hydrocarbon removal using bioelectrochemical systems have been reviewed. This also concerns PAH precursors: total petroleum hydrocarbons and diesel. Removal performances of PAH biodegradation in bioelectrochemical systems are discussed, focussing on configurational parameters such as anode and cathode designs as well as environmental parameters like porosity, salinity, adsorption and conductivity of soil and sediment that affect PAH biodegradation in BESs. The still scarcely available information on microbiological aspects of bioelectrochemical PAH removal is summarised here. This comprehensive review offers a better understanding of the parameters that affect the removal of PAHs within bioelectrochemical systems. In addition, future experimental setups are proposed in order to study syntrophic relationships between PAH
Biodegradation mechanism of linear alkylbenzenesulfonate-14C

International Nuclear Information System (INIS)

Kubodera, Tadayoshi; Muto, Toshio; Yamamoto, Tatsuo

1978-01-01

The biodegradation of linear alkylbenzenesulfonate- 14 C (LAS- 14 C) tagged with 14 C at the linear side chain was studied on activated sludge by tracer method in addition to the methylene blue method which is widely employed in the biodegradation of LAS. It was found that there were three periods of rapid adsorption period, acclimation period, and degradation process. The radiolysis of dodecylbenzenesulfonate was studied on irradiating by 5000 Ci 60 Co source. The decomposition products were identified by GLC and GC-MS spectrometry after desulfonation. 1-Tetralone, 1-indanone, 4-methyl-1-tetralone, naphthalene et al. were found in them. (author)
Modelling as a tool when interpreting biodegradation of micro pollutants in activated sludge systems

DEFF Research Database (Denmark)

Press-Kristensen, Kåre; Lindblom, Erik Ulfson; Henze, Mogens

2007-01-01

The aims of the present work were to improve the biodegradation of the endocrine disrupting micro pollutant, bisphenol A (BPA), used as model compound in an activated sludge system and to underline the importance of modelling the system. Previous results have shown that BPA mainly is degraded under...
Biodegradation of phenol-formaldehyde resins modified with commercial lignins

Energy Technology Data Exchange (ETDEWEB)

Bernard, M.; Nicolau, V. V. [Universidad Tecnologica Nacional (UTN), Cordoba (Argentina); Sponon, M.; Estenoz, D.A. [Instituto de Desarrollo Tecnologico para la Industria Quimica (INTEC/UNL/CONICET), Santa Fe (Argentina)

2014-07-01

Full text: In this work the biodegradation of partially-modified resols with 10% w/w of sodium lignosulfonate and 10 and 20 % w/w of Kraft lignin type is studied. The experimental work involved preliminary studies of biodegradation in Petri dish (clear zones), the degradation of resols by enzymatic attack of Pseudomonas aeruginosa under aerobic conditions for a period of 200 days and the characterization of the polymers before and after biodegradation by FT-IR and RMN spectroscopy, gas chromatography (GC) and scanning electron microscopy (SEM). The number of viable cells showed a significant increase during the process. However, the gravimetric analysis was not sufficient to check the biodegradation. The results indicated that endocellular enzymes could be involved. It was observed that the presence of low concentrations of toxic substances released during degradation of the material may have inhibitory effects. Resoles were synthesized in Centro S. A. San Francisco Cordoba, Argentina. (author)
Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe.

Science.gov (United States)

Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H

2015-12-01

Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp=200...600 μm, porosity ε=0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol)=0 after t=6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest. Copyright © 2015 Elsevier B.V. All rights
Development of a biodegradable bone cement

International Nuclear Information System (INIS)

Yusof Abdullah; Nurhaslinda Ee Abdullah; Wee Pee Chai; Norita Mohd Zain

2002-01-01

Biodegradable bone cement is a newly developed bone repair material, which is able to give immediate support to the implant area, and does not obstruct the bone repairing and regeneration process through appropriate biodegradation rate, which is synchronized with the mechanical load it should bear. The purpose of this study is to locally produce biodegradable bone cement using HA as absorbable filler. The cement is composed of an absorbable filler and unsaturated polyester for 100% degradation. Cross-linking effect is achieved through the action of poly (vinyl pyrrol lidone) (PVP) and an initiator. On the other hand, PPF was synthesized using direct esterification method. Characteristics of the bone cement were studied; these included the curing time, cross-linking effect and curing temperature. The products were characterized using X-Ray diffraction (XRD) to perform phase analysis and Scanning Electrons Microscopes to determine the morphology. The physical and mechanical properties of the bone cement were also investigated. The biocompatibility of the bone cement was tested using simulated body physiological solution. (Author)
C, Cl and H compound-specific isotope analysis to assess natural versus Fe(0) barrier-induced degradation of chlorinated ethenes at a contaminated site

Energy Technology Data Exchange (ETDEWEB)

Audí-Miró, Carme, E-mail: carmeaudi@ub.edu [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), Martí Franquès s/n, 08028, Barcelona (Spain); Cretnik, Stefan [Institute of Groundwater Ecology, Helmholtz Zentrum München-National Research Center for Environmental Health, Ingolstädter Landstrasse 1, D-85764 Neuherberg (Germany); Torrentó, Clara; Rosell, Mònica [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), Martí Franquès s/n, 08028, Barcelona (Spain); Shouakar-Stash, Orfan [Department of Earth & Environmental Sciences, 200 University Ave. W, N2L 3G1 Waterloo, Ontario (Canada); Otero, Neus [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), Martí Franquès s/n, 08028, Barcelona (Spain); Palau, Jordi [Université de Neuchâtel, CHYN - Centre d' Hydrogéologie, Rue Emile-Argand 11, CH-2000 Neuchâtel (Switzerland); and others

2015-12-15

Highlights: • {sup 13}C to evaluate natural chlorinated ethenes biodegradation. • {sup 13}C to evaluate the efficiency of a zero-valent iron-permeable reactive barrier. • {sup 13}C-{sup 37}Cl to discriminate biotic from abiotic degradation of cis-dichloroethene. • {sup 13}C-{sup 37}Cl-{sup 2}H of cis-DCE and TCE to elucidate different contaminant sources. - Abstract: Compound-specific isotopic analysis of multiple elements (C, Cl, H) was tested to better assess the effect of a zero-valent iron-permeable reactive barrier (ZVI-PRB) installation at a site contaminated with tetrachloroethene (PCE) and trichloroethene (TCE). The focus was on (1) using {sup 13}C to evaluate natural chlorinated ethene biodegradation and the ZVI-PRB efficiency; (2) using dual element {sup 13}C-{sup 37}Cl isotopic analysis to distinguish biotic from abiotic degradation of cis-dichloroethene (cis-DCE); and (3) using {sup 13}C-{sup 37}Cl-{sup 2}H isotopic analysis of cis-DCE and TCE to elucidate different contaminant sources. Both biodegradation and degradation by ZVI-PRB were indicated by the metabolites that were detected and the {sup 13}C data, with a quantitative estimate of the ZVI-PRB efficiency of less than 10% for PCE. Dual element {sup 13}C-{sup 37}Cl isotopic plots confirmed that biodegradation was the main process at the site including the ZVI-PRB area. Based on the carbon isotope data, approximately 45% and 71% of PCE and TCE, respectively, were estimated to be removed by biodegradation. {sup 2}H combined with {sup 13}C and {sup 37}Cl seems to have identified two discrete sources contributing to the contaminant plume, indicating the potential of δ{sup 2}H to discriminate whether a compound is of industrial origin, or whether a compound is formed as a daughter product during degradation.
C, Cl and H compound-specific isotope analysis to assess natural versus Fe(0) barrier-induced degradation of chlorinated ethenes at a contaminated site

International Nuclear Information System (INIS)

Audí-Miró, Carme; Cretnik, Stefan; Torrentó, Clara; Rosell, Mònica; Shouakar-Stash, Orfan; Otero, Neus; Palau, Jordi

2015-01-01

Highlights: • 13 C to evaluate natural chlorinated ethenes biodegradation. • 13 C to evaluate the efficiency of a zero-valent iron-permeable reactive barrier. • 13 C- 37 Cl to discriminate biotic from abiotic degradation of cis-dichloroethene. • 13 C- 37 Cl- 2 H of cis-DCE and TCE to elucidate different contaminant sources. - Abstract: Compound-specific isotopic analysis of multiple elements (C, Cl, H) was tested to better assess the effect of a zero-valent iron-permeable reactive barrier (ZVI-PRB) installation at a site contaminated with tetrachloroethene (PCE) and trichloroethene (TCE). The focus was on (1) using 13 C to evaluate natural chlorinated ethene biodegradation and the ZVI-PRB efficiency; (2) using dual element 13 C- 37 Cl isotopic analysis to distinguish biotic from abiotic degradation of cis-dichloroethene (cis-DCE); and (3) using 13 C- 37 Cl- 2 H isotopic analysis of cis-DCE and TCE to elucidate different contaminant sources. Both biodegradation and degradation by ZVI-PRB were indicated by the metabolites that were detected and the 13 C data, with a quantitative estimate of the ZVI-PRB efficiency of less than 10% for PCE. Dual element 13 C- 37 Cl isotopic plots confirmed that biodegradation was the main process at the site including the ZVI-PRB area. Based on the carbon isotope data, approximately 45% and 71% of PCE and TCE, respectively, were estimated to be removed by biodegradation. 2 H combined with 13 C and 37 Cl seems to have identified two discrete sources contributing to the contaminant plume, indicating the potential of δ 2 H to discriminate whether a compound is of industrial origin, or whether a compound is formed as a daughter product during degradation.
Occurrence and removal of pharmaceutically active compounds in sewage treatment plants with different technologies

Science.gov (United States)

Ying, Guang-Guo; Kookana, Rai S.; Kolpin, Dana W.

2009-01-01

Occurrence of eight selected pharmaceutically active compounds (PhACs; caffeine, carbamazepine, triclosan, gemfibrozil, diclofenac, ibuprofen, ketoprofen and naproxen) were investigated in effluents from fifteen sewage treatment plants (STPs) across South Australia. In addition, a detailed investigation into the removal of these compounds was also carried out in four STPs with different technologies (Plant A: conventional activated sludge; plant B: two oxidation ditches; plant C: three bioreactors; and plant D: ten lagoons in series). The concentrations of these compounds in the effluents from the fifteen STPs showed substantial variations among the STPs, with their median concentrations ranging from 26 ng/L for caffeine to 710 ng/L for carbamazepine. Risk assessment based on the "worst case scenario" of the monitoring data from the present study suggested potential toxic risks to aquatic organisms posed by carbamazepine, triclosan and diclofenac associated with such effluent discharge. With the exception of carbamazepine and gemfibrozil, significant concentration decreases between influent and effluent were observed in the four STPs studied in more detail. Biodegradation was found to be the main mechanism for removing concentrations from the liquid waste stream for the PhACs within the four STPs, while adsorption onto sludge appeared to be a minor process for all target PhACs except for triclosan. Some compounds (e.g. gemfibrozil) exhibited variable removal efficiencies within the four STPs. Plant D (10 lagoons in series) was least efficient in the removal of the target PhACs; significant biodegradation of these compounds only occurred from the sixth or seventh lagoon.
Hydroxyapatite-Coated Magnesium-Based Biodegradable Alloy: Cold Spray Deposition and Simulated Body Fluid Studies

Science.gov (United States)

Noorakma, Abdullah C. W.; Zuhailawati, Hussain; Aishvarya, V.; Dhindaw, B. K.

2013-10-01

A simple modified cold spray process in which the substrate of AZ51 alloys were preheated to 400 °C and sprayed with hydroxyapatite (HAP) using high pressure cold air nozzle spray was designed to get biocompatible coatings of the order of 20-30 μm thickness. The coatings had an average modulus of 9 GPa. The biodegradation behavior of HAP-coated samples was tested by studying with simulated body fluid (SBF). The coating was characterized by FESEM microanalysis. ICPOES analysis was carried out for the SBF solution to know the change in ion concentrations. Control samples showed no aluminum corrosion but heavy Mg corrosion. On the HAP-coated alloy samples, HAP coatings started dissolving after 1 day but showed signs of regeneration after 10 days of holding. All through the testing period while the HAP coating got eroded, the surface of the sample got deposited with different apatite-like compounds and the phase changed with course from DCPD to β-TCP and β-TCMP. The HAP-coated samples clearly improved the biodegradability of Mg alloy, attributed to the dissolution and re-precipitation of apatite showed by the coatings as compared to the control samples.
Geochemical indicators of anaerobic biodegradation of BTEX

International Nuclear Information System (INIS)

Wilson, J.T.; Kampbell, D.; Hutchins, S.; Wilson, B.; Kennedy, L.G.

1992-01-01

In the late 1970s, a leaking underground pipeline released petroleum hydrocarbons to a shallow, water-table aquifer in Kansas. Approximately six acres surrounding the release contain hydrocarbons at residual saturation. Parts of the release have acclimated and are carrying out anaerobic biodegradation of benzene, toluene, and the xylenes, Analysis of ground water from monitoring wells in areas that have acclimated reveal high concentrations of methane, less than -.1/liter oxygen, millimolar concentrations of acetate, and strongly reducing redox potentials. There is also a marked shift in the radio of the concentration of individual compounds to the total concentration of petroleum hydrocarbons

External validation of EPIWIN biodegradation models.

Science.gov (United States)

Posthumus, R; Traas, T P; Peijnenburg, W J G M; Hulzebos, E M

2005-01-01

The BIOWIN biodegradation models were evaluated for their suitability for regulatory purposes. BIOWIN includes the linear and non-linear BIODEG and MITI models for estimating the probability of rapid aerobic biodegradation and an expert survey model for primary and ultimate biodegradation estimation. Experimental biodegradation data for 110 newly notified substances were compared with the estimations of the different models. The models were applied separately and in combinations to determine which model(s) showed the best performance. The results of this study were compared with the results of other validation studies and other biodegradation models. The BIOWIN models predict not-readily biodegradable substances with high accuracy in contrast to ready biodegradability. In view of the high environmental concern of persistent chemicals and in view of the large number of not-readily biodegradable chemicals compared to the readily ones, a model is preferred that gives a minimum of false positives without a corresponding high percentage false negatives. A combination of the BIOWIN models (BIOWIN2 or BIOWIN6) showed the highest predictive value for not-readily biodegradability. However, the highest score for overall predictivity with lowest percentage false predictions was achieved by applying BIOWIN3 (pass level 2.75) and BIOWIN6.
Dissolution Coupled Biodegradation of Pce by Inducing In-Situ Biosurfactant Production Under Anaerobic Conditions

Science.gov (United States)

Dominic, J.; Nambi, I. M.

2013-12-01

Biosurfactants have proven to enhance the bioavailability and thereby elevate the rate of degradation of Light Non Aqueous Phase Liquids (LNAPLs) such as crude oil and petroleum derivatives. In spite of their superior characteristics, use of these biomolecules for remediation of Dense Non Aqueous Phase Liquids (DNAPLs) such as chlorinated solvents is still not clearly understood. In this present study, we have investigated the fate of tetrachloroethylene (PCE) by inducing in-situ biosurfactants production, a sustainable option which hypothesizes increase in bioavailability of LNAPLs. In order to understand the effect of biosurfactants on dissolution and biodegradation under the inducement of in-situ biosurfactant production, batch experiments were conducted in pure liquid media. The individual influence of each process such as biosurfactant production, dissolution of PCE and biodegradation of PCE were studied separately for getting insights on the synergistic effect of each process on the fate of PCE. Finally the dissolution coupled biodegradation of non aqueous phase PCE was studied in conditions where biosurfactant production was induced by nitrate limitation. The effect of biosurfactants was differentiated by repeating the same experiments were the biosurfactant production was retarded. The overall effect of in-situ biosurfactant production process was evaluated by use of a mathematical model. The process of microbial growth, biosurfactant production, dissolution and biodegradation of PCE were translated as ordinary differential equations. The modelling exercise was mainly performed to get insight on the combined effects of various processes that determine the concentration of PCE in its aqueous and non-aqueous phases. Model simulated profiles of PCE with the kinetic coefficients evaluated earlier from individual experiments were compared with parameters fitted for observations in experiments with dissolution coupled biodegradation process using optimization
Degradation of 5-FU by means of advanced (photo)oxidation processes: UV/H{sub 2}O{sub 2}, UV/Fe{sup 2+}/H{sub 2}O{sub 2} and UV/TiO{sub 2} — Comparison of transformation products, ready biodegradability and toxicity

Energy Technology Data Exchange (ETDEWEB)

Lutterbeck, Carlos Alexandre, E-mail: lutterbeck@leuphana.de [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Graduate Program in Environmental Technology, Universidade de Santa Cruz do Sul — UNISC, Av. Independência, 2293, CEP 96815-900 Santa Cruz do Sul, Rio Grande do Sul (Brazil); Wilde, Marcelo Luís, E-mail: wilde@leuphana.de [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Baginska, Ewelina, E-mail: ewelina.baginska@leuphana.de [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Leder, Christoph, E-mail: cleder@leuphana.de [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Faculty of Sustainability, Leuphana University of Lüneburg, Scharnhorststraße 1/C13, DE-21335 Lüneburg (Germany); Machado, Ênio Leandro, E-mail: enio@unisc.br [Graduate Program in Environmental Technology, Universidade de Santa Cruz do Sul — UNISC, Av. Independência, 2293, CEP 96815-900 Santa Cruz do Sul, Rio Grande do Sul (Brazil); and others

2015-09-15

The present study investigates the degradation of the antimetabolite 5-fluorouracil (5-FU) by three different advanced photo oxidation processes: UV/H{sub 2}O{sub 2}, UV/Fe{sup 2+}/H{sub 2}O{sub 2} and UV/TiO{sub 2}. Prescreening experiments varying the H{sub 2}O{sub 2} and TiO{sub 2} concentrations were performed in order to set the best catalyst concentrations in the UV/H{sub 2}O{sub 2} and UV/TiO{sub 2} experiments, whereas the UV/Fe{sup 2+}/H{sub 2}O{sub 2} process was optimized varying the pH, Fe{sup 2+} and H{sub 2}O{sub 2} concentrations by means of the Box–Behnken design (BBD). 5-FU was quickly removed in all the irradiation experiments. The UV/Fe{sup 2+}/H{sub 2}O{sub 2} and UV/TiO{sub 2} processes achieved the highest degree of mineralization, whereas the lowest one resulted from the UV/H{sub 2}O{sub 2} treatment. Six transformation products were formed during the advanced (photo)oxidation processes and identified using low and high resolution mass spectrometry. Most of them were formed and further eliminated during the reactions. The parent compound of 5-FU was not biodegraded, whereas the photolytic mixture formed in the UV/H{sub 2}O{sub 2} treatment after 256 min showed a noticeable improvement of the biodegradability in the closed bottle test (CBT) and was nontoxic towards Vibrio fischeri. In silico predictions showed positive alerts for mutagenic and genotoxic effects of 5-FU. In contrast, several of the transformation products (TPs) generated along the processes did not provide indications for mutagenic or genotoxic activity. One exception was TP with m/z 146 with positive alerts in several models of bacterial mutagenicity which could demand further experimental testing. Results demonstrate that advanced treatment can eliminate parent compounds and its toxicity. However, transformation products formed can still be toxic. Therefore toxicity screening after advanced treatment is recommendable. - Highlights: • Full primary elimination of 5-FU was
Biodegradation of crude oil in Arctic subsurface water from the Disko Bay (Greenland) is limited

DEFF Research Database (Denmark)

Scheibye, Katrine; Christensen, Jan H.; Johnsen, Anders R.

2017-01-01

Biological degradation is the main process for oil degradation in a subsurface oil plume. There is, however, little information on the biodegradation potential of Arctic, marine subsurface environments. We therefore investigated oil biodegradation in microcosms at 2 °C containing Arctic subsurfac...... for the C1-naphthalenes. To conclude, the marine subsurface microorganisms from the Disko Bay had the potential for biodegradation of n-alkanes and isoprenoids while the metabolically complex and toxic PACs and their alkylated homologs remained almost unchanged.......Biological degradation is the main process for oil degradation in a subsurface oil plume. There is, however, little information on the biodegradation potential of Arctic, marine subsurface environments. We therefore investigated oil biodegradation in microcosms at 2 °C containing Arctic subsurface...... seawater from the Disko Bay (Greenland) and crude oil at three concentrations of 2.5-10 mg/L. Within 71 days, the total petroleum hydrocarbon concentration decreased only by 18 ± 18% for an initial concentration of 5 mg/L. The saturated alkanes nC13-nC30 and the isoprenoids iC18-iC21 were biodegraded...
On statistical analysis of compound point process

Czech Academy of Sciences Publication Activity Database

Volf, Petr

2006-01-01

Roč. 35, 2-3 (2006), s. 389-396 ISSN 1026-597X R&D Projects: GA ČR(CZ) GA402/04/1294 Institutional research plan: CEZ:AV0Z10750506 Keywords : counting process * compound process * hazard function * Cox -model Subject RIV: BB - Applied Statistics, Operational Research
Biodegradation of lubricant oil

African Journals Online (AJOL)

M

2012-09-25

Sep 25, 2012 ... lubricating oil, showed high biodegradation efficiency for different used lubricating oils. Capability of ..... amount after biodegradation showed no difference in the .... products polluted sites in Elele, Rivers State, Ngeria.
Impact of initial biodegradability on sludge anaerobic digestion enhancement by thermal pretreatment.

Science.gov (United States)

Carrère, Hélène; Bougrier, Claire; Castets, Delphine; Delgenès, Jean Philippe

2008-11-01

Thermal treatments with temperature ranging from 60 to 210 degrees C were applied to 6 waste-activated sludge samples originating from high or medium load, extended aeration wastewater treatment processes that treated different wastewaters (urban, urban and industrial or slaughterhouse). COD sludge solubilisation was linearly correlated with the treatment temperature on the whole temperature range and independently of the sludge samples. Sludge batch mesophilic biodegradability increased with treatment temperature up to 190 degrees C. In this temperature range, biodegradability enhancement or methane production increase by thermal hydrolysis was shown to be a function of sludge COD solubilisation but also of sludge initial biodegradability. The lower the initial biodegradability means the higher efficiency of thermal treatment.
Cascaded processing in written compound word production

Directory of Open Access Journals (Sweden)

Raymond eBertram

2015-04-01

Full Text Available In this study we investigated the intricate interplay between central linguistic processing and peripheral motor processes during typewriting. Participants had to typewrite two-constituent (noun-noun Finnish compounds in response to picture presentation while their typing behavior was registered. As dependent measures we used writing onset time to assess what processes were completed before writing and inter-key intervals to assess what processes were going on during writing. It was found that writing onset time was determined by whole word frequency rather than constituent frequencies, indicating that compound words are retrieved as whole orthographic units before writing is initiated. In addition, we found that the length of the first syllable also affects writing onset time, indicating that the first syllable is fully prepared before writing commences. The inter-key interval results showed that linguistic planning is not fully ready before writing, but cascades into the motor execution phase. More specifically, inter-key intervals were largest at syllable and morpheme boundaries, supporting the view that additional linguistic planning takes place at these boundaries. Bigram and trigram frequency also affected inter-key intervals with shorter intervals corresponding to higher frequencies. This can be explained by stronger memory traces for frequently co-occurring letter sequences in the motor memory for typewriting. These frequency effects were even larger in the second than in the first constituent, indicating that low-level motor memory starts to become more important during the course of writing compound words. We discuss our results in the light of current models of morphological processing and written word production.
Cascaded processing in written compound word production.

Science.gov (United States)

Bertram, Raymond; Tønnessen, Finn Egil; Strömqvist, Sven; Hyönä, Jukka; Niemi, Pekka

2015-01-01

In this study we investigated the intricate interplay between central linguistic processing and peripheral motor processes during typewriting. Participants had to typewrite two-constituent (noun-noun) Finnish compounds in response to picture presentation while their typing behavior was registered. As dependent measures we used writing onset time to assess what processes were completed before writing and inter-key intervals to assess what processes were going on during writing. It was found that writing onset time was determined by whole word frequency rather than constituent frequencies, indicating that compound words are retrieved as whole orthographic units before writing is initiated. In addition, we found that the length of the first syllable also affects writing onset time, indicating that the first syllable is fully prepared before writing commences. The inter-key interval results showed that linguistic planning is not fully ready before writing, but cascades into the motor execution phase. More specifically, inter-key intervals were largest at syllable and morpheme boundaries, supporting the view that additional linguistic planning takes place at these boundaries. Bigram and trigram frequency also affected inter-key intervals with shorter intervals corresponding to higher frequencies. This can be explained by stronger memory traces for frequently co-occurring letter sequences in the motor memory for typewriting. These frequency effects were even larger in the second than in the first constituent, indicating that low-level motor memory starts to become more important during the course of writing compound words. We discuss our results in the light of current models of morphological processing and written word production.
The assessment of the energetic compound 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-Hexaazaisowurtzitane (CL-20) degradability in soil

International Nuclear Information System (INIS)

Strigul, Nikolay; Braida, Washington; Christodoulatos, Christos; Balas, Wendy; Nicolich, Steven

2006-01-01

CL-20 is a relatively new energetic compound with applications in explosive and propellant formulations. Currently, information about the fate of CL-20 in ecological systems is scarce. The aim of this study is to evaluate the biodegradability of CL-20 in soil environments. Four soils were used where initial CL-20 concentrations (above water solubility) ranged from 125 to 1500 mg of CL-20 per kg dry soil (corresponding to the concentrations derived from unexploded ordnance, low order detonation, or manufacturing spills). CL-20 appears to be biodegradable in soil under anaerobic conditions, and additions of organic substrates can substantially accelerate this process. However, CL-20 is not degraded in soil under aerobic conditions kept in the dark at temperatures up to 30 deg. C without organic amendments. Additions of starch or cellulose promote the biodegradation of CL-20 under aerobic conditions. Soil microbial community mediated biodegradation and plant uptake appears to enhance CL-20 biodegradation, the latter suggesting a possible route for CL-20 to entry in the food chain. - Biodegradation and plant uptake suggest possible entry of CL-20 into food chain
Absorbable and biodegradable polymers

CERN Document Server

Shalaby, Shalaby W

2003-01-01

INTRODUCTION NOTES: Absorbable/Biodegradable Polymers: Technology Evolution. DEVELOPMENT AND APPLICATIONOF NEW SYSTEMS: Segmented Copolyesters with Prolonged Strength Retention Profiles. Polyaxial Crystalline Fiber-Forming Copolyester. Polyethylene Glycol-Based Copolyesters. Cyanoacrylate-Based Systems as Tissue Adhesives. Chitosan-Based Systems. Hyaluronic Acid-Based Systems. DEVELOPMENTS IN PREPARATIVE, PROCESSING, AND EVALUATION METHODS: New Approaches to the Synthesis of Crystalline. Fiber-Forming Aliphatic Copolyesters. Advances in Morphological Development to Tailor the Performance of Me
Drug loaded biodegradable load-bearing nanocomposites for damaged bone repair

Science.gov (United States)

Gutmanas, E. Y.; Gotman, I.; Sharipova, A.; Psakhie, S. G.; Swain, S. K.; Unger, R.

2017-09-01

In this paper we present a short review-scientific report on processing and properties, including in vitro degradation, of load bearing biodegradable nanocomposites as well as of macroporous 3D scaffolds for bone ingrowth. Biodegradable implantable devices should slowly degrade over time and disappear with ingrown of natural bone replacing the synthetic graft. Compared to low strength biodegradable polymers, and brittle CaP ceramics, biodegradable CaP-polymer and CaP-metal nanocomposites, mimicking structure of natural bone, as well as strong and ductile metal nanocomposites can provide to implantable devices both strengths and toughness. Nanostructuring of biodegradable β-TCP (tricalcium phosphate)-polymer (PCL and PLA), β-TCP-metal (FeMg and FeAg) and of Fe-Ag composites was achieved employing high energy attrition milling of powder blends. Nanocomposite powders were consolidated to densities close to theoretical by high pressure consolidation at ambient temperature—cold sintering, with retention of nanoscale structure. The strength of developed nanocomposites was significantly higher as compared with microscale composites of the same or similar composition. Heat treatment at moderate temperatures in hydrogen flow resulted in retention of nanoscale structure and higher ductility. Degradation of developed biodegradable β-TCP-polymer, β-TCP-metal and of Fe-Ag nanocomposites was studied in physiological solutions. Immersion tests in Ringer's and saline solution for 4 weeks resulted in 4 to 10% weight loss and less than 50% decrease in compression or bending strength, the remaining strength being significantly higher than the values reported for other biodegradable materials. Nanostructuring of Fe-Ag based materials resulted also in an increase of degradation rate because of creation on galvanic Fe-Ag nanocouples. In cell culture experiments, the developed nanocomposites supported the attachment the human osteoblast cells and exhibited no signs of cytotoxicity
Biodegradability and mechanical properties of starch films from Andean crops.

Science.gov (United States)

Torres, F G; Troncoso, O P; Torres, C; Díaz, D A; Amaya, E

2011-05-01

Different Andean crops were used to obtain starches not previously reported in literature as raw material for the production of biodegradable polymers. The twelve starches obtained were used to prepare biodegradable films by casting. Water and glycerol were used as plasticizers. The mechanical properties of the starch based films were assessed by means of tensile tests. Compost tests and FTIR tests were carried out to assess biodegradability of films. The results show that the mechanical properties (UTS, Young's modulus and elongation at break) of starch based films strongly depend on the starch source used for their production. We found that all the starch films prepared biodegrade following a three stage process and that the weight loss rate of all the starch based films tested was higher than the weight loss rate of the cellulose film used as control. Copyright © 2011 Elsevier B.V. All rights reserved.
Application of compound specific 13C isotope investigations of chlorinated hydrocarbons in contaminated groundwaters

International Nuclear Information System (INIS)

Osenbrueck, K.; Heidinger, M.; Voropaev, A.; Ertl, S.; Eichinger, L.

2002-01-01

Full text: Chlorinated hydrocarbons are one of the most common pollutants found in groundwater. Due to complex contamination situations with overlapping contamination plumes the assessment of the organic contaminants requires the installation of expensive observation wells and high analytical effort. Here the determination of the stable isotope ratio 13 C/ 12 C of the organic compounds offers a promising and efficient tool to investigate the origin and the biodegradation characteristics of the chlorinated hydrocarbons in groundwater. The application of the method is based on characteristic isotope fingerprints, differing in chlorinated solvents. This isotope fingerprint is derived from different production pathways and is not influenced by transport or by retardation processes in the underground. Due to the fact, that two different contaminations can easily be distinguished by isotope ratios, an improved distinction of spatially and temporally different contamination plumes might be possible. In course of biologically mediated degradation processes a shift of the isotope ratios between the precursor and the product can frequently be observed, such as with denitrification or sulfate reduction processes. The isotope fractionation is due to a preferential reaction of the bonds formed by the lighter isotopes and leads to a progressive enrichment of the heavy isotopes in the precursor while the product becomes depleted in the heavy isotopes. Biological degradation of the highly chlorinated hydrocarbons is due to a co-metabolic dechlorinisation. Tetrachloroethene (PCE) for example degrades under anoxic conditions via trichloroethene (TCE) to cis-1,2-dichloroethene (cDCE). Subsequent degradation to vinyl chloride (VC) and ethene may appear under aerobic as well as reducing environments depending on the site specific conditions. In several laboratory studies it has been shown, that biodegradation of the chlorinated hydrocarbons is accompanied by an isotope fractionation of
Biodegradation kinetics for pesticide exposure assessment.

Science.gov (United States)

Wolt, J D; Nelson, H P; Cleveland, C B; van Wesenbeeck, I J

2001-01-01

Understanding pesticide risks requires characterizing pesticide exposure within the environment in a manner that can be broadly generalized across widely varied conditions of use. The coupled processes of sorption and soil degradation are especially important for understanding the potential environmental exposure of pesticides. The data obtained from degradation studies are inherently variable and, when limited in extent, lend uncertainty to exposure characterization and risk assessment. Pesticide decline in soils reflects dynamically coupled processes of sorption and degradation that add complexity to the treatment of soil biodegradation data from a kinetic perspective. Additional complexity arises from study design limitations that may not fully account for the decline in microbial activity of test systems, or that may be inadequate for considerations of all potential dissipation routes for a given pesticide. Accordingly, kinetic treatment of data must accommodate a variety of differing approaches starting with very simple assumptions as to reaction dynamics and extending to more involved treatments if warranted by the available experimental data. Selection of the appropriate kinetic model to describe pesticide degradation should rely on statistical evaluation of the data fit to ensure that the models used are not overparameterized. Recognizing the effects of experimental conditions and methods for kinetic treatment of degradation data is critical for making appropriate comparisons among pesticide biodegradation data sets. Assessment of variability in soil half-life among soils is uncertain because for many pesticides the data on soil degradation rate are limited to one or two soils. Reasonable upper-bound estimates of soil half-life are necessary in risk assessment so that estimated environmental concentrations can be developed from exposure models. Thus, an understanding of the variable and uncertain distribution of soil half-lives in the environment is
[Exposure to metal compounds in occupational galvanic processes].

Science.gov (United States)

Surgiewicz, Jolanta; Domański, Wojciech

2006-01-01

Occupational galvanic processes are provided in more than 600 small and medium enterprises in Poland. Workers who deal with galvanic coating are exposed to heavy metal compounds: tin, silver, copper and zinc. Some of them are carcinogenic, for example, hexavalent chromium compounds, nickel and cadmium compounds. Research covered several tens of workstations involved in chrome, nickel, zinc, tin, silver, copper and cadmium plating. Compounds of metals present in the air were determined: Cr, Ni, Cd, Sn, Ag--by atomic absorption spectrometry with electrothermal atomization (ET-AAS) and Zn--by atomic absorption spectrometry with flame atomization (F-AAS). The biggest metal concentrations--of silver and copper--were found at workstations of copper, brass, cadmium, nickel and chrome plating, conducted at the same time. Significant concentrations of copper were found at workstations of maintenance bathing and neutralizing of sewage. The concentrations of metals did not exceed Polish MAC values. MAC values were not exceeded for carcinogenic chromium(VI), nickel or cadmium, either. In galvanic processes there was no hazard related to single metals or their compounds, even carcinogenic ones. Combined exposure indicators for metals at each workstation did not exceed 1, either. However, if there are even small quantities of carcinogenic agents, health results should always be taken into consideration.
Influence of Concentration and Salinity on the Biodegradability of Organic Additives in Hydraulic Fracturing Fluid

Science.gov (United States)

Mouser, P. J.; Kekacs, D.

2014-12-01

One of the risks associated with the use of hydraulic fracturing technologies for energy development is the potential release of hydraulic fracturing-related fluids into surface waters or shallow aquifers. Many of the organic additives used in hydraulic fracturing fluids are individually biodegradable, but little is know on how they will attenuate within a complex organic fluid in the natural environment. We developed a synthetic hydraulic fracturing fluid based on disclosed recipes used by Marcellus shale operators to evaluate the biodegradation potential of organic additives across a concentration (25 to 200 mg/L DOC) and salinity gradient (0 to 60 g/L) similar to Marcellus shale injected fluids. In aerobic aqueous solutions, microorganisms removed 91% of bulk DOC from low SFF solutions and 57% DOC in solutions having field-used SFF concentrations within 7 days. Under high SFF concentrations, salinity in excess of 20 g/L inhibited organic compound biodegradation for several weeks, after which time the majority (57% to 75%) of DOC remained in solution. After SFF amendment, the initially biodiverse lake or sludge microbial communities were quickly dominated (>79%) by Pseudomonas spp. Approximately 20% of added carbon was converted to biomass while the remainder was respired to CO2 or other metabolites. Two alcohols, isopropanol and octanol, together accounted for 2-4% of the initial DOC, with both compounds decreasing to below detection limits within 7 days. Alcohol degradation was associated with an increase in acetone at mg/L concentrations. These data help to constrain the biodegradation potential of organic additives in hydraulic fracturing fluids and guide our understanding of the microbial communities that may contribute to attenuation in surface waters.
Biodegradable multifunctional oil production chemicals: Thermal polyaspartates

International Nuclear Information System (INIS)

Ross, R.J.; Ravenscroft, P.D.

1996-01-01

The paper deals with biodegradable oil production chemicals. Control of both mineral scale and corrosion with a single, environmentally acceptable material is an ambitious goal. Polyaspartate polymers represent a significant milestone in the attainment of this goal. Thermal polyaspartates (TPA) are polycarboxylate polymers derived via thermal condensation of the naturally occurring amino acid aspartic acid. These protein-like polymers are highly biodegradable and non-toxic, and are produced by an environmentally benign manufacturing process. TPAs exhibit excellent mineral scale inhibition activity and CO 2 corrosion control. Laboratory data on scale inhibition and corrosion control in the North Sea oil field production applications is presented. 8 refs., 2 figs., 6 tabs
Biodegradable multifunctional oil production chemicals: Thermal polyaspartates

Energy Technology Data Exchange (ETDEWEB)

Ross, R J [Donlar Corporation (United States); Ravenscroft, P D [BP Exploration Operating Company, (United Kingdom)

1997-12-31

The paper deals with biodegradable oil production chemicals. Control of both mineral scale and corrosion with a single, environmentally acceptable material is an ambitious goal. Polyaspartate polymers represent a significant milestone in the attainment of this goal. Thermal polyaspartates (TPA) are polycarboxylate polymers derived via thermal condensation of the naturally occurring amino acid aspartic acid. These protein-like polymers are highly biodegradable and non-toxic, and are produced by an environmentally benign manufacturing process. TPAs exhibit excellent mineral scale inhibition activity and CO{sub 2} corrosion control. Laboratory data on scale inhibition and corrosion control in the North Sea oil field production applications is presented. 8 refs., 2 figs., 6 tabs.
Biodegradation of New Polymer Foundry Binders for the Example of the Composition Polyacrylic Acid/Starch

Directory of Open Access Journals (Sweden)

Beata Grabowska

2011-04-01

Full Text Available The investigations on the biodegradation process pathway of the new polymer binders for the example of water soluble compositionpolyacrylic acid/starch are presented in the hereby paper. Degradation was carried out in water environment and in a soil. Thedetermination of the total oxidation biodegradation in water environment was performed under laboratory conditions in accordance with the static water test system (Zahn-Wellens method, in which the mixture undergoing biodecomposition contained inorganic nutrient,activated sludge and the polymer composition, as the only carbon and energy source. The biodecomposition progress of the polymercomposition sample in water environment was estimated on the basis of the chemical oxygen demand (COD measurements and thedetermination the biodegradation degree, Rt, during the test. These investigations indicated that the composition polyacrylic acid/starchconstitutes the fully biodegradable material in water environment. The biodegradation degree Rt determined in the last 29th day of the test duration achieved 65%, which means that the investigated polymer composition can be considered to be fully biodegradable.During the 6 months biodegradation process of the cross-linked sample of the polymer composition in a garden soil several analysis ofsurface and structural changes, resulting from the sample decomposition, were performed. Those were: thermal analyses (TG-DSC,structural analyses (Raman spectroscopy and microscopic analyses (optical microscopy, AFM.

Identification of TCE and PCE sorption and biodegradation parameters in a sandy aquifer for fate and transport modelling: batch and column studies.

Science.gov (United States)

Kret, E; Kiecak, A; Malina, G; Nijenhuis, I; Postawa, A

2015-07-01

The main aim of this study was to determine the sorption and biodegradation parameters of trichloroethene (TCE) and tetrachloroethene (PCE) as input data required for their fate and transport modelling in a Quaternary sandy aquifer. Sorption was determined based on batch and column experiments, while biodegradation was investigated using the compound-specific isotope analysis (CSIA). The aquifer materials medium (soil 1) to fine (soil 2) sands and groundwater samples came from the representative profile of the contaminated site (south-east Poland). The sorption isotherms were approximately linear (TCE, soil 1, K d = 0.0016; PCE, soil 1, K d = 0.0051; PCE, soil 2, K d = 0.0069) except for one case in which the best fitting was for the Langmuir isotherm (TCE, soil 2, K f = 0.6493 and S max = 0.0145). The results indicate low retardation coefficients (R) of TCE and PCE; however, somewhat lower values were obtained in batch compared to column experiments. In the column experiments with the presence of both contaminants, TCE influenced sorption of PCE, so that the R values for both compounds were almost two times higher. Non-significant differences in isotope compositions of TCE and PCE measured in the observation points (δ(13)C values within the range of -23.6 ÷ -24.3‰ and -26.3 ÷-27.7‰, respectively) indicate that biodegradation apparently is not an important process contributing to the natural attenuation of these contaminants in the studied sandy aquifer.
Fungal bio-degradation of 14C-parathion

International Nuclear Information System (INIS)

Mohamed, G. A.; Abo-El Seoud, M. A.

2012-12-01

1 4 'C-parathion (670 Bq) was applied to mineral salt medium (MSM) to examine and evaluate its biodegradation by some fungi. The studied isolates were Alternaria alternate, Fusarium oxysporim and trichoderma viride. The inoculated media were incubated at 30 o C for periods of 2, 4, 6 and 8 days. Ta each interval, mycelia were separated from nutrient solution and extracted for its radioactivity. However, non extractable compounds were liberated by combustion. Quantitative and qualitative analysis were carried out for the radioactive compound in mycelia l extracts and residues as well as the fungal culture filtrate. Balance sheet for total recovered radioactive compounds was concluded 1 4 'C-parathion metabolism was expressed as original compound, polar metabolite, non polar metabolites and non extractable residues and then degradation rate was calculated. araesults indicated that there was continuous penetration for the radioactivity into mycelia tissues and the maximum, accumulation was recorded by Fusarium Oxysporium. The fungi under investigation showed considerable variations regarding their capacity to degrade the radioactive pesticide. Trichoderma viride exhibited the maximum capability to catabolism the the 1 4C -parathion as it exerted the maximum degradation rate. Fusarium and Alternate alter nata showed less degradation rates for the 1 4C - pesticide under investigation. (Author)
Hybrid Moving Bed Biofilm Reactor for the biodegradation of benzotriazoles and hydroxy-benzothiazole in wastewater

DEFF Research Database (Denmark)

Mazioti, Aikaterini A.; Stasinakis, Athanasios S.; Psoma, Aikaterini K.

2017-01-01

and a settling tank. The average removal of target compounds ranged between 41% (4-methyl-1H-benzotriazole; 4TTR) and 88% (2-hydroxybenzothiazole; OHBTH). Except for 4TTR, degradation mainly occurred in the first bioreactor. Calculation of biodegradation constants in batch experiments and application of a model...
Continuous biodegradation of sulfanilic acid in a multi-stage packed bed reactor

International Nuclear Information System (INIS)

Salazar-Huerta, A.; Velazquez-Garcia, A.; Cobos-Vasconcelos, D. de los.; Juarez-Ramirez, C.; Ruiz-Ordaz, N.; Galindez-Mayer, J.

2009-01-01

Sulfanilic acid SA is an aromatic amine derived from the azo-bond cleavage of several textile dyes. Recalcitrance and toxicity of this amine is high, and with frequency it could be found as an aquatic contaminant; thus biodegradation process for its removal are justified. Although the SA molecule contains carbon, nitrogen and sulphur, its C:N:S proportion is unbalanced for microbial growth in a biodegradation process; thus nutrient complementation should be necessary for its complete removal. (Author)
Mineralization and biodegradability enhancement of Methyl Orange dye by an effective advanced oxidation process

International Nuclear Information System (INIS)

Paul Guin, Jhimli; Bhardwaj, Y.K.; Varshney, Lalit

2017-01-01

An effective process for the oxidation of Methyl Orange dye (MO) was determined by comparing the mineralization efficiency between two advanced oxidation processes (AOPs) viz., ozonolysis and gamma radiolysis in presence and absence of an added inorganic salt potassium persulfate (K_2S_2O_8). The effects of various operating parameters such as ozone flow rate and reaction temperature were optimized to achieve the best possible mineralization extent of MO by ozonolysis. The mineralization efficiency of MO was significantly enhanced during gamma radiolysis in presence of K_2S_2O_8 (γ+K_2S_2O_8) compared to in absence of K_2S_2O_8. The presence of methyl group at the amine of phenyl ring assisted the mineralization of dye during γ+K_2S_2O_8. The oxygen-equivalent chemical-oxidation capacities (OCC) of ozonolysis and γ+K_2S_2O_8 for 75% mineralization of the dye solution were calculated as 7.008 and 0.0336 kg equiv. O_2 m"−"3, respectively which signifies that γ+K_2S_2O_8 can be explored as an effective AOP. The non-biodegradable MO dye solution became biodegradable even after the dose of 0.5 kGy during γ+K_2S_2O_8 compared to 1 kGy in absence of K_2S_2O_8. The study concludes that a lower dose γ+K_2S_2O_8 could be one of the efficient pretreatment steps before undergoing biological degradation of dye solution. - Highlights: • Systematic investigation was performed for the treatment of Methyl Orange dye solution. • AOPs investigated were ozonolysis and gamma radiolysis. • The OCC and % mineralizations of the AOPs were compared. • Gamma radiolysis in presence of K_2S_2O_8 was found as most effective AOP.
Challenges and opportunities of biodegradable plastics: A mini review.

Science.gov (United States)

Rujnić-Sokele, Maja; Pilipović, Ana

2017-02-01

The concept of materials coming from nature with environmental advantages of being biodegradable and/or biobased (often referred to as bioplastics) is very attractive to the industry and to the consumers. Bioplastics already play an important role in the fields of packaging, agriculture, gastronomy, consumer electronics and automotive, but still they have a very low share in the total production of plastics (currently about 1% of the about 300 million tonnes of plastic produced annually). Biodegradable plastics are often perceived as the possible solution for the waste problem, but biodegradability is just an additional feature of the material to be exploited at the end of its life in specific terms, in the specific disposal environment and in a specific time, which is often forgotten. They should be used as a favoured choice for the applications that demand a cheap way to dispose of the item after it has fulfilled its job (e.g. for food packaging, agriculture or medical products). The mini-review presents the opportunities and future challenges of biodegradable plastics, regarding processing, properties and waste management options.
Biodegradable Sonobuoy Decelerators

Science.gov (United States)

2015-06-01

of Water Temperature and the Presence of Salt on the Disintegration Time of MonoSol A200 PVOH...polyhydroxyalkanoate (PHA). The proposed film would disintegrate , dissolve, and eventually biodegrade to prevent long-term effects on marine life. Ensuring no...Standard Specification for Non-Floating Biodegradable Plastics in the Marine Environment. Results showed that no PHA grades were toxic to the marine
Biodegradation of petroleum oil by certain bacterial strains

International Nuclear Information System (INIS)

Zakaria, A.E.M.

1998-01-01

Balaeam base oil was chosen as a model oil in the present study through which some abiotic treatments were implemented aiming at attenuating its naphthenic and aromatic contents; such as the adsorptive technique and the gamma-irradiation technique . In an attempt to apply the biodegrading bacteria as oil pollutant bio indicators upon coastal water samples, a correlation between hydrocarbon concentration and the relative enumeration of the bacterial oil degraders was detected for some litter locations along the mediterranean Sea shore west and east Delta, Suez canal. and suez gulf. 24 petroleum utilizing bacterial isolates were isolated from El-Zayteia port (suez) and identified by morphological, physiological and environmental examination . the biodegradation capacity of the isolates towards the chosen model oil and its separate components was studied in comparison with the standard isolate pseudomonas aeruginosa. Further, the role of the bacterial plasmids taking part in the biodegradation process was investigated as well
Biodegradation of benzalkonium chlorides singly and in mixtures by a Pseudomonas sp. isolated from returned activated sludge

International Nuclear Information System (INIS)

Khan, Adnan Hossain; Topp, Edward; Scott, Andrew; Sumarah, Mark; Macfie, Sheila M.; Ray, Madhumita B.

2015-01-01

Highlights: • Pseudomonas sp. degraded two benzalkonium chlorides: BDDA and BDTA. • Although BDTA biodegraded at low concentration, it inhibited the degradation of BDDA. • For BDDA, two transformation products indicate two sites of bacterial activity. • "1"4C-labelled BDDA was mineralized to "1"4CO_2 within 300 h. - Abstract: Bactericidal cationic surfactants such as quaternary ammonium compounds (QACs) are widely detected in the environment, and found at mg kg"−"1 concentrations in biosolids. Although individual QACs are amenable to biodegradation, it is possible that persistence is increased for mixtures of QACs with varying structure. The present study evaluated the biodegradation of benzyl dimethyl dodecyl ammonium chloride (BDDA) singly and in the presence of benzyl dimethyl tetradecyl ammonium chloride (BDTA) using Pseudomonas sp., isolated from returned activated sludge. Growth was evaluated, as was biodegradation using "1"4C and HPLC-MS methods. BDTA was more toxic to growth of Pseudomonas sp. compared to BDDA, and BDTA inhibited BDDA biodegradation. The benzyl ring of [U-"1"4C-benzyl] BDDA was readily and completely mineralized. The detection of the transformation products benzyl methyl amine and dodecyl dimethyl amine in spent culture liquid was consistent with literature. Overall, this study demonstrates the antagonistic effect of interactions on biodegradation of two widely used QACs suggesting further investigation on the degradation of mixture of QACs in wastewater effluents and biosolids.
The effects of LMWOAs on biodegradation of multi-component PAHs in aqueous solution using dual-wavelength fluorimetry

International Nuclear Information System (INIS)

Wei Xingyuan; Sang Lingzi; Chen Jianing; Zhu Yaxian; Zhang Yong

2009-01-01

Biodegradation of dissolved fluorene (Flu), phenanthrene (Ph) and pyrene (Py), three polycyclic aromatic hydrocarbons (PAHs), singly or as a mixture of the three, by two bacterial strains, MEBIC 5140 (Mycobacterium flavescens) and MEBIC 5141 (Mycobacterium scrofulaceum), as well as the effects of low molecular weight organic acids (LMWOAs), e.g. malic acid, citric acid and butyric acid on biodegradation of the three PAHs in mineral salts medium aqueous solution were investigated using a newly established dual-wavelength fluorimetric method. The results showed that biodegradation processes can be monitored simultaneously, quickly and simply by dual-wavelength fluorimetry. Both co-metabolism and inhibitory effects were found during the biodegradation of the three PAHs by MEBIC 5140 and MEBIC 5141. Positive effects of butyric acid and negative effects of citric acid on biodegradation of the three PAHs in a mixture were observed. - Biodegradation processes of dissolved multi-component PAHs in a mixture and effects of LMWOAs were investigated using a dual-wavelength fluorimetry.
Experience with compound words influences their processing: An eye movement investigation with English compound words.

Science.gov (United States)

Juhasz, Barbara J

2016-11-14

Recording eye movements provides information on the time-course of word recognition during reading. Juhasz and Rayner [Juhasz, B. J., & Rayner, K. (2003). Investigating the effects of a set of intercorrelated variables on eye fixation durations in reading. Journal of Experimental Psychology: Learning, Memory and Cognition, 29, 1312-1318] examined the impact of five word recognition variables, including familiarity and age-of-acquisition (AoA), on fixation durations. All variables impacted fixation durations, but the time-course differed. However, the study focused on relatively short, morphologically simple words. Eye movements are also informative for examining the processing of morphologically complex words such as compound words. The present study further examined the time-course of lexical and semantic variables during morphological processing. A total of 120 English compound words that varied in familiarity, AoA, semantic transparency, lexeme meaning dominance, sensory experience rating (SER), and imageability were selected. The impact of these variables on fixation durations was examined when length, word frequency, and lexeme frequencies were controlled in a regression model. The most robust effects were found for familiarity and AoA, indicating that a reader's experience with compound words significantly impacts compound recognition. These results provide insight into semantic processing of morphologically complex words during reading.
Histological evaluation of different biodegradable and non-biodegradable membranes implanted subcutaneously in rats

DEFF Research Database (Denmark)

Zhao, S; Pinholt, E M; Madsen, J E

2000-01-01

Different types of biodegradable membranes have become available for guided tissue regeneration. The purpose of this study was to evaluate histologically three different biodegradable membranes (Bio-Gide, Resolut and Vicryl) and one non-biodegradable membrane (expanded polytetrafluoroethylene/e-PTFE...... that e-PTFE was well tolerated and encapsulated by a fibrous connective tissue capsule. There was capsule formation around Resolut and Vicryl and around Bio-Gide in the early phase there was a wide inflammatory zone already. e-PTFE and Vicryl were stable materials while Resolut and Bio-Gide fragmented...
Rare earth intermetallic compounds produced by a reduction-diffusion process

International Nuclear Information System (INIS)

Cech, R.E.

1975-01-01

A reduction-diffusion process is given for producing novel rare earth intermetallic compounds, such as cobalt--rare earth intermetallic compounds, especially compounds useful in preparing permanent magnets. A particulate mixture of rare earth metal halide, cobalt and calcium hydride is heated to effect reduction of the rare earth metal halide and to diffuse the resulting rare earth metal into the cobalt to form the intermetallic compound
Biodegradable modified Phba systems

International Nuclear Information System (INIS)

Aniscenko, L.; Dzenis, M.; Erkske, D.; Tupureina, V.; Savenkova, L.; Muizniece - Braslava, S.

2004-01-01

Compositions as well as production technology of ecologically sound biodegradable multicomponent polymer systems were developed. Our objective was to design some bio plastic based composites with required mechanical properties and biodegradability intended for use as biodegradable packaging. Significant characteristics required for food packaging such as barrier properties (water and oxygen permeability) and influence of γ-radiation on the structure and changes of main characteristics of some modified PHB matrices was evaluated. It was found that barrier properties were plasticizers chemical nature and sterilization with γ-radiation dependent and were comparable with corresponding values of typical polymeric packaging films. Low γ-radiation levels (25 kGy) can be recommended as an effective sterilization method of PHB based packaging materials. Purposely designed bio plastic packaging may provide an alternative to traditional synthetic packaging materials without reducing the comfort of the end-user due to specific qualities of PHB - biodegradability, Biocompatibility and hydrophobic nature
Enzymatic oxidative biodegradation of nanoparticles: Mechanisms, significance and applications

Energy Technology Data Exchange (ETDEWEB)

Vlasova, Irina I. [Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15219 (United States); Research Institute for Physico-Chemical Medicine, Federal Medico-Biological Agency, Moscow 119453 (Russian Federation); Kapralov, Alexandr A. [Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15219 (United States); Michael, Zachary P.; Burkert, Seth C. [Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Shurin, Michael R. [Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA 15261 (United States); Department of Immunology, University of Pittsburgh Medical Center, Pittsburgh, PA 15261 (United States); Star, Alexander [Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Shvedova, Anna A., E-mail: ats@cdc.gov [Pathology and Physiology Research Branch, Health Effects Laboratory Division (HELD), National Institute for Occupational Safety and Health (NIOSH) and Department of Physiology and Pharmacology, West Virginia University, Morgantown, WV 26505 (United States); Kagan, Valerian E., E-mail: kagan@pitt.edu [Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15219 (United States); Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Departments of Pharmacology and Chemical Biology and Radiation Oncology, University of Pittsburgh, Pittsburgh, PA 15260 (United States)

2016-05-15

Biopersistence of carbon nanotubes, graphene oxide (GO) and several other types of carbonaceous nanomaterials is an essential determinant of their health effects. Successful biodegradation is one of the major factors defining the life span and biological responses to nanoparticles. Here, we review the role and contribution of different oxidative enzymes of inflammatory cells – myeloperoxidase, eosinophil peroxidase, lactoperoxidase, hemoglobin, and xanthine oxidase – to the reactions of nanoparticle biodegradation. We further focus on interactions of nanomaterials with hemoproteins dependent on the specific features of their physico-chemical and structural characteristics. Mechanistically, we highlight the significance of immobilized peroxidase reactive intermediates vs diffusible small molecule oxidants (hypochlorous and hypobromous acids) for the overall oxidative biodegradation process in neutrophils and eosinophils. We also accentuate the importance of peroxynitrite-driven pathways realized in macrophages via the engagement of NADPH oxidase- and NO synthase-triggered oxidative mechanisms. We consider possible involvement of oxidative machinery of other professional phagocytes such as microglial cells, myeloid-derived suppressor cells, in the context of biodegradation relevant to targeted drug delivery. We evaluate the importance of genetic factors and their manipulations for the enzymatic biodegradation in vivo. Finally, we emphasize a novel type of biodegradation realized via the activation of the “dormant” peroxidase activity of hemoproteins by the nano-surface. This is exemplified by the binding of GO to cyt c causing the unfolding and ‘unmasking’ of the peroxidase activity of the latter. We conclude with the strategies leading to safe by design carbonaceous nanoparticles with optimized characteristics for mechanism-based targeted delivery and regulatable life-span of drugs in circulation. - Highlights: • Nanoparticles can be degraded by
Biodegradation of hard keratins by two bacillus strains.

Science.gov (United States)

Laba, Wojciech; Rodziewicz, Anna

2014-02-01

Extensive quantities of keratinic by-products are disposed annually by animal-processing industry, causing a mounting ecological problem due to extreme resilience of these materials to enzymatic breakdown. There is a growing trend to apply cheap and environment-friendly methods to recycle keratinic wastes. Soil bacteria of profound keratinolytic potential, especially spore-forming rods from the genus Bacillus, play a significant role in keratinase-mediated biodegradation of keratins, therefore could be effective in hastening their biodegradation. Keratin hydrolysis in microbial cultures is one of the most promising techniques not only to utilize this protein but also to obtain valuable by products. The study was undertaken to investigate the biodegradation process of various keratinic materials by two Bacillus strains. Two keratinolytic strains, Bacillus cereus and B. polymyxa, were subject to cultures in the presence of several keratinic appendages, like chicken feathers, barbs and rachea of ostrich feathers, pig bristle, lamb wool, human hair and stratum corneum of epidermis, as main nutrient sources. Bacterial ability to decompose these waste materials was evaluated, at the background of keratinase and protease biosynthesis, in brief four-day cultures. Keratinolytic activity was measured on soluble keratin preparation and proteases were assayed on casein. Additionally, amounts of liberated proteins, amino acids and thiols were evaluated. Residual keratin weight was tested afterwards. Both tested strains proved to be more adapted for fast biodegradation of feather β-keratins than hair-type α-keratins. B. cereus revealed its significant proteolytic potential, especially on whole chicken feathers (230 PU) and stratum corneum (180 PU), but also on separated barbs and rachea, which appeared to be moderate protease inducers. Keratinolytic activity of B. cereus was comparable on most substrates and maximum level obtained was 11 KU. B. polymyxa was found to be a
Dual partitioning and attachment effects of rhamnolipid on pyrene biodegradation under bioavailability restrictions

International Nuclear Information System (INIS)

Congiu, Eleonora; Parsons, John R.; Ortega-Calvo, José-Julio

2015-01-01

We investigated the effects of different bioavailability scenarios on the rhamnolipid-enhanced biodegradation of pyrene by the representative polycyclic aromatic hydrocarbon degrader Mycobacterium gilvum VM552. This biosurfactant enhanced biodegradation when pyrene was provided in the form of solid crystals; no effect was observed when the same amount of the chemical was preloaded on polydimethylsiloxane (PDMS). An enhanced effect was observed when pyrene was sorbed into soil but not with the dissolved compound. Synchronous fluorescence spectrophotometry and liquid scintillation were used to determine the phase exchange of pyrene. We also investigated the phase distribution of bacteria. Our results suggest that the rhamnolipid can enhance the biodegradation of pyrene by micellar solubilization and increase diffusive uptake. These mechanisms increase substrate acquisition by bacterial cells at exposure concentrations well above the half-saturation constant for active uptake. The moderate solubilization of pyrene from PDMS by the rhamnolipid and the prevention of cell attachment may explain the lack of enhancement for pyrene-preloaded PDMS. - Highlights: • Rhamnolipid biosurfactant can enhance the biodegradation of pyrene. • The enhancement depends on how the bacteria are exposed to the pollutant. • Rhamnolipid stimulates if pyrene is provided by dissolution from crystals. • No effect is observed if pyrene is provided by partitioning from a silicone polymer. • This lack of effect is due to the balance between enhanced dissolution and decreased cell attachment. - Rhamnolipid-enhanced biodegradation of pyrene may depend on the exposure regime. Moderate solubilization from difficult matrices and prevention of cell attachment may have no effect
Biodegradation of volatile organic compounds by five fungal species

Energy Technology Data Exchange (ETDEWEB)

Qi, B.; Moe, W.M. [Dept. of Civil and Environmental Engineering, Louisiana State Univ., Baton Rouge, LA (United States); Kinney, K.A. [Dept. of Civil Engineering, Univ. of Texas, Austin (United States)

2002-07-01

Five fungal species, Cladosporium resinae (ATCC 34066), Cladosporium sphaerospermum (ATCC 200384), Exophiala lecanii-corni (CBS 102400), Mucor rouxii (ATCC 44260), and Phanerochaete chrysosporium (ATCC 24725), were tested for their ability to degrade nine compounds commonly found in industrial off-gas emissions. Fungal cultures inoculated on ceramic support media were provided with volatile organic compounds (VOCs) via the vapor phase as their sole carbon and energy sources. Compounds tested included aromatic hydrocarbons (benzene, ethylbenzene, toluene, and styrene), ketones (methyl ethyl ketone, methyl isobutyl ketone, and methyl propyl ketone), and organic acids (n-butyl acetate, ethyl 3-ethoxypropionate). Experiments were conducted using three pH values ranging from 3.5 to 6.5. Fungal ability to degrade each VOC was determined by observing the presence or absence of visible growth on the ceramic support medium during a 30-day test period. Results indicate that E. lecanii-corni and C. sphaerospermum can readily utilize each of the nine VOCs as a sole carbon and energy source. P. chrysosporium was able to degrade all VOCs tested except for styrene under the conditions imposed. C. resinae was able to degrade both organic acids, all of the ketones, and some of the aromatic compounds (ethylbenzene and toluene); however, it was not able to grow utilizing benzene or styrene under the conditions tested. With the VOCs tested, M. rouxii produced visible growth only when supplied with n-butyl acetate or ethyl 3-ethoxypropionate. Maximum growth for most fungi was observed at a pH of approximately 5.0. The experimental protocol utilized in these studies is a useful tool for assessing the ability of different fungal species to degrade gas-phase VOCs under conditions expected in a biofilter application. (orig.)
Fixation of zygomatic and mandibular fractures with biodegradable plates.

Science.gov (United States)

Degala, Saikrishna; Shetty, Sujeeth; Ramya, S

2013-01-01

In this prospective study, 13 randomly selected patients underwent treatment for zygomatic-complex fractures (2 site fractures) and mandibular fractures using 1.5 / 2 / 2.5-mm INION CPS biodegradable plates and screws. To assess the fixation of zygomatic-complex and mandibular fractures with biodegradable copolymer osteosynthesis system. In randomly selected 13 patients, zygomatic-complex and mandibular fractures were plated using resorbable plates and screws using Champy's principle. All the cases were evaluated clinically and radiologically for the type of fracture, need for the intermaxillary fixation (IMF) and its duration, duration of surgery, fixation at operation, state of reduction at operation, state of bone union after operation, anatomic reduction, paresthesia, occlusal discrepancies, soft tissue infection, immediate and late inflammatory reactions related to biodegradation process, and any need for the removal of the plates. Descriptives, Frequencies, and Chi-square test were used. In our study, the age group range was 5 to 55 years. Road traffic accidents accounted for the majority of patients six, (46.2%). Postoperative occlusal discrepancies were found in seven patients as mild to moderate, which resolved with IMF for 1-8 weeks. There were minimal complications seen and only as soft tissue infection. Use of biodegradable osteosynthesis system is a reliable alternative method for the fixation of zygomatic-complex and mandibular fractures. The biodegradable system still needs to be refined in material quality and handling to match the stability achieved with metal system. Biodegradable plates and screws is an ideal system for pediatric fractures with favorable outcome.
Modern mass spectrometry in the characterization and degradation of biodegradable polymers

International Nuclear Information System (INIS)

Rizzarelli, Paola; Carroccio, Sabrina

2014-01-01

Graphical abstract: -- Highlights: •Recent trends in the structural characterization of biodegradable polymers by MALDI and ESI MS are discussed. •MALDI MS as a noteworthy tool to follow the synthetic polymerization route of biodegradable materials is evidenced. •Elucidation of degradation mechanisms by modern MS techniques is examined. •ESI MS and HPLC–ESI MS are highlighted as highly suitable methods for structural and quantitative analysis of water-soluble biodegradation products. •Novel MS methods developed ad hoc and new MALDI matrices for biodegradable polymers are reviewed. -- Abstract: In the last decades, the solid-waste management related to the extensively growing production of plastic materials, in concert with their durability, have stimulated increasing interest in biodegradable polymers. At present, a variety of biodegradable polymers has already been introduced onto the market and can now be competitive with non biodegradable thermoplastics in different fields (packaging, biomedical, textile, etc.). However, a significant economical effort is still directed in tailoring structural properties in order to further broaden the range of applications without impairing biodegradation. Improving the performance of biodegradable materials requires a good characterization of both physico-chemical and mechanical parameters. Polymer analysis can involve many different features including detailed characterization of chemical structures and compositions as well as average molecular mass determination. It is of outstanding importance in troubleshooting of a polymer manufacturing process and for quality control, especially in biomedical applications. This review describes recent trends in the structural characterization of biodegradable materials by modern mass spectrometry (MS). It provides an overview of the analytical tools used to evaluate their degradation. Several successful applications of MALDI-TOF MS (matrix assisted laser desorption ionization

Modern mass spectrometry in the characterization and degradation of biodegradable polymers

Energy Technology Data Exchange (ETDEWEB)

Rizzarelli, Paola, E-mail: paola.rizzarelli@cnr.it; Carroccio, Sabrina

2014-01-15

Graphical abstract: -- Highlights: •Recent trends in the structural characterization of biodegradable polymers by MALDI and ESI MS are discussed. •MALDI MS as a noteworthy tool to follow the synthetic polymerization route of biodegradable materials is evidenced. •Elucidation of degradation mechanisms by modern MS techniques is examined. •ESI MS and HPLC–ESI MS are highlighted as highly suitable methods for structural and quantitative analysis of water-soluble biodegradation products. •Novel MS methods developed ad hoc and new MALDI matrices for biodegradable polymers are reviewed. -- Abstract: In the last decades, the solid-waste management related to the extensively growing production of plastic materials, in concert with their durability, have stimulated increasing interest in biodegradable polymers. At present, a variety of biodegradable polymers has already been introduced onto the market and can now be competitive with non biodegradable thermoplastics in different fields (packaging, biomedical, textile, etc.). However, a significant economical effort is still directed in tailoring structural properties in order to further broaden the range of applications without impairing biodegradation. Improving the performance of biodegradable materials requires a good characterization of both physico-chemical and mechanical parameters. Polymer analysis can involve many different features including detailed characterization of chemical structures and compositions as well as average molecular mass determination. It is of outstanding importance in troubleshooting of a polymer manufacturing process and for quality control, especially in biomedical applications. This review describes recent trends in the structural characterization of biodegradable materials by modern mass spectrometry (MS). It provides an overview of the analytical tools used to evaluate their degradation. Several successful applications of MALDI-TOF MS (matrix assisted laser desorption ionization
Biodegradation of petroleum hydrocarbons at low temperatures

International Nuclear Information System (INIS)

Whyte, L. G.; Greer, C W.

1999-01-01

Bioremediation of contaminated Arctic sites has been proposed as the logistically and economically most favorable solution despite the known technical difficulties. The difficulties involve the inhibition of pollutants removal by biodegradation below freezing temperatures and the relative slowness of the process to remove enough hydrocarbon pollutants during the above-freezing summer months. Despite these formidable drawbacks, biodegradation of hydrocarbon contaminants is possible even in below-zero temperatures, especially if indigenous psychrophilic and psychrotropic micro-organism are used. This paper reports results of a study involving several hydrocarbon-degrading psychrotropic bacteria and suggests bioaugmentation with specific cold-adapted organisms and/or biostimulation with commercial fertilizers for enhancing degradation of specific contaminants in soils from northern Canada. An evaluation of the biodegradation potential of hydrocarbon contaminated soils in the high Arctic suggested that the contaminated soils contained sufficient numbers of cold-adapted hydrocarbon-degrading bacteria and that the addition of fertilizer was sufficient to enhance the level of hydrocarbon degradation at low ambient summer temperatures. 9 refs., 2 tabs., 3 figs
Assessment of Fenton's reagent and ozonation as pre-treatments for increasing the biodegradability of aqueous diethanolamine solutions from an oil refinery gas sweetening process.

Science.gov (United States)

Durán-Moreno, A; García-González, S A; Gutiérrez-Lara, M R; Rigas, F; Ramírez-Zamora, R M

2011-02-28

The aim of this work was to evaluate the efficiency of three chemical oxidation processes for increasing the biodegradability of aqueous diethanolamine solutions (aqueous DEA solutions), to be used as pre-treatments before a biological process. The raw aqueous DEA solution, sourced from a sour gas sweetening plant at a Mexican oil refinery, was first characterized by standardized physico-chemical methods. Then experiments were conducted on diluted aqueous DEA solutions to test the effects of Fenton's reagent, ozone and ozone-hydrogen peroxide on the removal of some physicochemical parameters of these solutions. Lastly, biodegradability tests based on Dissolved Organic Carbon Die Away OECD301-A, were carried out on a dilution of the raw aqueous DEA solution and on the treated aqueous DEA solutions, produced by applying the best experimental conditions determined during the aforementioned oxidation tests. Experimental results showed that for aqueous DEA solutions treated with Fenton's reagent, the best degradation rate (70%) was obtained at pH 2.8, with Fe(2+) and H(2)O(2) at doses of 1000 and 10,000 mg/L respectively. In the ozone process, the best degradation (60%) was observed in aqueous DEA solution (100 mg COD/L), using 100 mg O(3)/L at pH 5. In the ozone-hydrogen peroxide process, no COD or DOC removals were observed. The diluted spent diethanolamine solution showed its greatest increase in biodegradability after a reaction period of 28 days when treated with Fenton's reagent, but after only 15 days in the case of ozonation. Copyright © 2011 Elsevier B.V. All rights reserved.
Enhanced micropollutant biodegradation and assessment of nitrous oxide concentration reduction in wastewater treated by acclimatized sludge bioaugmentation.

Science.gov (United States)

Boonnorat, Jarungwit; Techkarnjanaruk, Somkiet; Honda, Ryo; Ghimire, Anish; Angthong, Sivakorn; Rojviroon, Thammasak; Phanwilai, Supaporn

2018-05-11

This research investigated the micropollutant biodegradation and nitrous oxide (N 2 O) concentration reduction in high strength wastewater treated by two-stage activated sludge (AS) systems with (bioaugmented) and without (non-bioaugmented) acclimatized sludge bioaugmentation. The bioaugmented and non-bioaugmented systems were operated in parallel for 228 days, with three levels of concentrations of organics, nitrogen, and micropollutants in the influent: conditions 1 (low), 2 (moderate), and 3 (high). The results showed that, under condition 1, both systems efficiently removed the organic and nitrogen compounds. However, the bioaugmented system was more effective in the micropollutant biodegradation and N 2 O concentration reduction than the non-bioaugmented one. Under condition 2, the nitrogen and micropollutant biodegradation efficiency of the non-bioaugmented system slightly decreased, while the N 2 O concentration declined in the bioaugmented system. Under condition 3, the treatment performance and N 2 O concentration abatement were substantially lowered as the compounds concentration increased. Further analysis also showed that the acclimatized sludge bioaugmentation increased the bacterial diversity in the system. In essence, the acclimatized sludge bioaugmentation strategy was highly effective for the influent with low compounds concentration, achieving the organics and nitrogen removal efficiencies of 92-97%, relative to 71-97% of the non-bioaugmented system. The micropollutant treatment efficiency of the bioaugmented system under condition 1 was 75-92%, indicating significant improvement in the treatment performance (p < 0.05), compared with 60-79% of the non-bioaugmented system. Copyright © 2018 Elsevier B.V. All rights reserved.
Biodegradation of free cyanide and subsequent utilisation of biodegradation by-products by Bacillus consortia: optimisation using response surface methodology.

Science.gov (United States)

Mekuto, Lukhanyo; Ntwampe, Seteno Karabo Obed; Jackson, Vanessa Angela

2015-07-01

A mesophilic alkali-tolerant bacterial consortium belonging to the Bacillus genus was evaluated for its ability to biodegrade high free cyanide (CN(-)) concentration (up to 500 mg CN(-)/L), subsequent to the oxidation of the formed ammonium and nitrates in a continuous bioreactor system solely supplemented with whey waste. Furthermore, an optimisation study for successful cyanide biodegradation by this consortium was evaluated in batch bioreactors (BBs) using response surface methodology (RSM). The input variables, that is, pH, temperature and whey-waste concentration, were optimised using a numerical optimisation technique where the optimum conditions were found to be as follows: pH 9.88, temperature 33.60 °C and whey-waste concentration of 14.27 g/L, under which 206.53 mg CN(-)/L in 96 h can be biodegraded by the microbial species from an initial cyanide concentration of 500 mg CN(-)/L. Furthermore, using the optimised data, cyanide biodegradation in a continuous mode was evaluated in a dual-stage packed-bed bioreactor (PBB) connected in series to a pneumatic bioreactor system (PBS) used for simultaneous nitrification, including aerobic denitrification. The whey-supported Bacillus sp. culture was not inhibited by the free cyanide concentration of up to 500 mg CN(-)/L, with an overall degradation efficiency of ≥ 99 % with subsequent nitrification and aerobic denitrification of the formed ammonium and nitrates over a period of 80 days. This is the first study to report free cyanide biodegradation at concentrations of up to 500 mg CN(-)/L in a continuous system using whey waste as a microbial feedstock. The results showed that the process has the potential for the bioremediation of cyanide-containing wastewaters.
Process for removing halogenated aliphatic and aromatic compounds from petroleum products

Science.gov (United States)

Googin, J.M.; Napier, J.M.; Travaglini, M.A.

1983-09-20

A process is described for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 1 fig.
Biodegradation of Lignocelluloses in Sewage Sludge Composting and Vermicomposting

Directory of Open Access Journals (Sweden)

Hosein Alidadi

2012-08-01

Full Text Available Please cite this article as: Alidadi H, Najafpour AA, Vafaee A, Parvaresh A, Peiravi R. Biodegradation of lignocelluloses in sewage sludge composting and vermicomposting. Arch Hyg Sci 2012;1(1:1-5. Aims of the Study: The aim of this study was to determine the amount of lignin degradation and biodegradation of organic matter and change of biomass under compost and vermicomposting of sewage sludge. Materials & Methods: Sawdust was added to sewage sludge at 1:3 weight bases to Carbon to Nitrogen ratio of 25:1 for composting or vermicomposting. Lignin and volatile solids were determined at different periods, of 0, 10, 30, 40 and 60 days of composting or vermicomposting period to determine the biodegradation of lignocellulose to lignin. Results were expressed as mean of two replicates and the comparisons among means were made using the least significant difference test calculated (p <0.05. Results: After 60 days of experiment period, the initial lignin increased from 3.46% to 4.48% for compost and 3.46% to 5.27% for vermicompost. Biodegradation of lignocellulose was very slow in compost and vermicompost processes. Vermicomposting is a much faster process than compost to convert lignocellulose to lignin (p <0.05. Conclusions: The organic matter losses in sewage sludge composting and vermicomposting are due to the degradation of the lignin fractions. By increasing compost age, the amount of volatile solids will decrease.
Biodegradation of ion-exchange media

International Nuclear Information System (INIS)

Bowerman, B.S.; Clinton, J.H.; Cowdery, S.R.

1988-08-01

Ion-exchange media, both bead resins and powdered filter media, are used in nuclear power plants to remove radioactivity from process water prior to reuse or environmental discharge. Since the ion- exchange media are made from synthetic hydrocarbon-based polymers, they may be susceptible to damage from biological activity. The purpose of this study was to investigate some of the more basic aspects of biodegradation of ion-exchange media, specifically to evaluate the ability of microorganisms to utilize the ion-exchange media or materials sorbed on them as a food source. The ASTM-G22 test, alone and combined with the Bartha Pramer respirometric method, failed to indicate the biodegradability of the ion-exchange media. The limitation of these methods was that they used a single test organism. In later phases of this study, a mixed microbial culture was grown from resin waste samples obtained from the BNL High Flux Beam Reactor. These microorganisms were used to evaluate the susceptibility of different types of ion-exchange media to biological attack. Qualitative assessments of biodegradability were based on visual observations of culture growths. Greater susceptibility was associated with increased turbidity in solution indicative of bacterial growth, and more luxuriant fungal mycelial growth in solution or directly on the ion-exchange resin beads. 21 refs., 9 figs., 18 tabs
Flexible biodegradable citrate-based polymeric step-index optical fiber.

Science.gov (United States)

Shan, Dingying; Zhang, Chenji; Kalaba, Surge; Mehta, Nikhil; Kim, Gloria B; Liu, Zhiwen; Yang, Jian

2017-10-01

Implanting fiber optical waveguides into tissue or organs for light delivery and collection is among the most effective ways to overcome the issue of tissue turbidity, a long-standing obstacle for biomedical optical technologies. Here, we report a citrate-based material platform with engineerable opto-mechano-biological properties and demonstrate a new type of biodegradable, biocompatible, and low-loss step-index optical fiber for organ-scale light delivery and collection. By leveraging the rich designability and processibility of citrate-based biodegradable polymers, two exemplary biodegradable elastomers with a fine refractive index difference and yet matched mechanical properties and biodegradation profiles were developed. Furthermore, we developed a two-step fabrication method to fabricate flexible and low-loss (0.4 db/cm) optical fibers, and performed systematic characterizations to study optical, spectroscopic, mechanical, and biodegradable properties. In addition, we demonstrated the proof of concept of image transmission through the citrate-based polymeric optical fibers and conducted in vivo deep tissue light delivery and fluorescence sensing in a Sprague-Dawley (SD) rat, laying the groundwork for realizing future implantable devices for long-term implantation where deep-tissue light delivery, sensing and imaging are desired, such as cell, tissue, and scaffold imaging in regenerative medicine and in vivo optogenetic stimulation. Copyright © 2017 Elsevier Ltd. All rights reserved.
Effects of halogenated aromatics/aliphatics and nitrogen(N)-heterocyclic aromatics on estimating the persistence of future pharmaceutical compounds using a modified QSAR model.

Science.gov (United States)

Lim, Seung Joo; Fox, Peter

2014-02-01

The effects of halogenated aromatics/aliphatics and nitrogen(N)-heterocyclic aromatics on estimating the persistence of future pharmaceutical compounds were investigated using a modified half life equation. The potential future pharmaceutical compounds investigated were approximately 2000 pharmaceutical drugs currently undergoing the United States Food and Drug Administration (US FDA) testing. EPI Suite (BIOWIN) model estimates the fates of compounds based on the biodegradability under aerobic conditions. While BIOWIN considered the biodegradability of a compound only, the half life equation used in this study was modified by biodegradability, sorption and cometabolic oxidation. It was possible that the potential future pharmaceutical compounds were more accurately estimated using the modified half life equation. The modified half life equation considered sorption and cometabolic oxidation of halogenated aromatic/aliphatics and nitrogen(N)-heterocyclic aromatics in the sub-surface, while EPI Suite (BIOWIN) did not. Halogenated aliphatics in chemicals were more persistent than halogenated aromatics in the sub-surface. In addition, in the sub-surface environment, the fates of organic chemicals were much more affected by halogenation in chemicals than by nitrogen(N)-heterocyclic aromatics. © 2013.
Biodegradable products by lipase biocatalysis.

Science.gov (United States)

Linko, Y Y; Lämsä, M; Wu, X; Uosukainen, E; Seppälä, J; Linko, P

1998-11-18

The interest in the applications of biocatalysis in organic syntheses has rapidly increased. In this context, lipases have recently become one of the most studied groups of enzymes. We have demonstrated that lipases can be used as biocatalyst in the production of useful biodegradable compounds. A number of examples are given. 1-Butyl oleate was produced by direct esterification of butanol and oleic acid to decrease the viscosity of biodiesel in winter use. Enzymic alcoholysis of vegetable oils without additional organic solvent has been little investigated. We have shown that a mixture of 2-ethyl-1-hexyl esters can be obtained in a good yield by enzymic transesterification from rapeseed oil fatty acids for use as a solvent. Trimethylolpropane esters were also similarly synthesized as lubricants. Finally, the discovery that lipases can also catalyze ester syntheses and transesterification reactions in organic solvent systems has opened up the possibility of enzyme catalyzed production of biodegradable polyesters. In direct polyesterification of 1,4-butanediol and sebacic acid, polyesters with a mass average molar mass of the order of 56,000 g mol-1 or higher, and a maximum molar mass of about 130,000 g mol-1 were also obtained by using lipase as biocatalyst. Finally, we have demonstrated that also aromatic polyesters can be synthesized by lipase biocatalysis, a higher than 50,000 g mol-1 mass average molar mass of poly(1,6-hexanediyl isophthalate) as an example.
Current knowledge on biodegradable microspheres in drug delivery.

Science.gov (United States)

Prajapati, Vipul D; Jani, Girish K; Kapadia, Jinita R

2015-08-01

Biodegradable microspheres have gained popularity for delivering a wide variety of molecules via various routes. These types of products have been prepared using various natural and synthetic biodegradable polymers through suitable techniques for desired delivery of various challenging molecules. Selection of biodegradable polymers and technique play a key role in desired drug delivery. This review describes an overview of the fundamental knowledge and status of biodegradable microspheres in effective delivery of various molecules via desired routes with consideration of outlines of various compendial and non-compendial biodegradable polymers, formulation techniques and release mechanism of microspheres, patents and commercial biodegradable microspheres. There are various advantages of using biodegradable polymers including promise of development with different types of molecules. Biocompatibility, low dosage and reduced side effects are some reasons why usage biodegradable microspheres have gained in popularity. Selection of biodegradable polymers and formulation techniques to create microspheres is the biggest challenge in research. In the near future, biodegradable microspheres will become the eco-friendly product for drug delivery of various genes, hormones, proteins and peptides at specific site of body for desired periods of time.
DEVELOPMENT OF ACTIVE AND BIODEGRADABLES CONTAINERS FOR AGRICULTURAL CROPS

Directory of Open Access Journals (Sweden)

Franco Poggio

2016-06-01

Full Text Available In this paper, the development of biodegradable containers for crops that could be transplanted directly and act as fertilizers is proposed. Bovine gelatin was chosen as the base material, which was processed in a mini-injector mixer with a concentrated urea solution acted as a plasticizer. Rheological and tensile tests were performed in order to evaluate the injection of gelatin based formulations and mechanical properties related to the proposed application. Taking into account that biodegradable materials have a low water resistance, the increment of container stability was proposed using a surface coating. In addition, the influence of moisture content, the soluble matter and swelling were studied and analyzed. It was observed that coated samples were significantly more stable than the control ones, which guarantees the feasibility of the selected system and its potential development of biodegradable containers.
THE USE OF BIOFILTRATION PROCESS TO REMOVE ORGANIC MATTER FROM GROUNDWATER

Directory of Open Access Journals (Sweden)

Dorota Papciak

2016-07-01

Full Text Available The article describes the research on the removal of organic matter from natural underground water using biofiltration process. The study was carried out in semi-technical scale on a model filter composed of activated carbon WD-extra. The development of biological activity in a biosorption bed, as well as observations on the relationship between the processes of sorption and biodegradation was evaluated based on the Eberhardt, Madsen, Sontheimer (EMS test. Leading operation control parameters of biologically active carbon filter BAF included: change of TOC content, dissolved oxygen and permanganate index. To evaluate the colonization of granular carbon determination of ATP value was used. The presence of the biofilm was found by observation using light and scanning microscopes. The organic compounds in the water taken were adsorbed 100% and 70% biodegradable. The combination of sorption process with biodegradation until depletion of activated carbon adsorption capacity allowed in the initial phase of coalbed work for the removal of organic matter in approx. 100% . Formation of biofilm at the right time allowed to extend the filtration cycle and helped lower the TOC by 70%, i.e. from 10 mg C/l to 3-4 mg C/l.
Assessment of current quality of biodegradable municipal waste separated by residents of Kroměříž

Directory of Open Access Journals (Sweden)

Bohdan Stejskal

2010-01-01

Full Text Available In an effort to meet the requirements for maximum material utilization, which is set forth in the Act No. 185/2001 Coll. on Waste and amendments to other Acts, and to achieve the objectives of the Waste Management Plan of the Czech Republic to reduce biodegradable waste going to landfill, a proposal for widespread deployment of separate collection and processing of biodegradable municipal waste in municipalities has become part of the amendment Act prepared by the ministry. In many places of the country pilot projects have been launched to test the technology and logistics of sorting, collecting, processing and utilizing biodegradable municipal waste separated by residents.Separate collection of biodegradable municipal waste in Kroměříž was launched as a pilot project in 1992. Despite all the residents’ education, the management of Biopas is not satisfied with the quality of biodegradable waste separation; problems occur especially in the residential area. Biodegradable waste separated by residents, due to its unacceptable amount of impurities, is transported to the landfill Kuchyňky near the village Zdounky 10 km distant but detailed data on the amount of impurities in separate biodegradable municipal waste were missing.Therefore an analysis of separate biodegradable municipal waste has been carried out. Individual samples were collected within two days of separate waste delivery, without any modifications (scattering, compaction. The sample size was at least 200 kg, the sample was manually sorted according to the Catalogue of Waste into biodegradable waste (200201, other non-biodegradable waste (200203 and biodegradable waste unsuitable for composting (e.g. animal by-products. It was found that the amount of unacceptable impurities in separate biodegradable waste considerably varies from 1 to 9 %wt.It can be concluded that the amount of unacceptable impurities in biowaste is too large to allow composting and compost production (in
Fate of pharmaceutical compounds in hydroponic mesocosms planted with Scirpus validus.

Science.gov (United States)

Zhang, Dong Qing; Gersberg, Richard M; Hua, Tao; Zhu, Junfei; Goyal, Manish Kumar; Ng, Wun Jern; Tan, Soon Keat

2013-10-01

A systematic approach to assess the fate of selected pharmaceuticals (carbamazepine, naproxen, diclofenac, clofibric acid and caffeine) in hydroponic mesocosms is described. The overall objective was to determine the kinetics of depletion (from solution) and plant uptake for these compounds in mesocosms planted with S. validus growing hydroponically. The potential for translocation of these pharmaceuticals from the roots to the shoots was also assessed. After 21 days of incubation, nearly all of the caffeine, naproxen and diclofenac were eliminated from solution, whereas carbamazepine and clofibric acid were recalcitrant to both photodegradation and biodegradation. The fact that the BAFs for roots for carbamazepine and clofibric acid were greater than 5, while the BAFs for naproxen, diclofenac and caffeine were less than 5, implied that the latter two compounds although recalcitrant to biodegradation, still had relatively high potential for plant uptake. Naproxen was sensitive to both photodegradation (30-42%) and biodegradation (>50%), while diclofenac was particularly sensitive (>70%) to photodegradation alone. No significant correlations (p > 0.05) were found between the rate constants of depletion or plant tissue levels of the pharmaceuticals and either log Kow or log Dow. Copyright © 2013 Elsevier Ltd. All rights reserved.
Measuring biodegradation of oil products by means of environmental forensic methods

International Nuclear Information System (INIS)

Gallego, J. R.; Garcia-Mtnez, M. J.; Ortiz, J. E.; Ortega, M.; Torres, T. de; Llamas, J. F.

2009-01-01

Bioremediation technologies are focused to the biodegradation of organic pollutants. This approach is particularly helpful when soils and/or groundwater are affected by oil products spills, given the satisfactory biodegradability of most hydrocarbons. However, during a bio-treatment the decreasing in pollutants concentration may be due to both biotic and biotic processes, whose distinction is very important, albeit difficult, in order to evaluate if bioremediation is being properly applied. (Author)
Hybrid Moving Bed Biofilm Reactor for the biodegradation of benzotriazoles and hydroxy-benzothiazole in wastewater

DEFF Research Database (Denmark)

Mazioti, Aikaterini A.; Stasinakis, Athanasios S.; Psoma, Aikaterini K.

2017-01-01

(CBTR) and 5-methyl-1H-benzotriazole (5TTR). Comparison of the HMBBR system with MBBR or AS systems from literature showed that the HMBBR system was more efficient for the biodegradation of the investigated chemicals. Biotransformation products of target compounds were identified using ultra high......-performance liquid chromatography, coupled with a quadrupole-time-of-flight high-resolution mass spectrometer (UHPLC-QToF-MS). Twenty two biotransformation products were tentatively identified, while retention time denoted the formation of more polar transformation products than the parent compounds....
The Potential of Lignolytic Trichoderma Isolates in LDPE (Low Density Polyethylene) Plastic Biodegradation

Science.gov (United States)

Hikmah, M.; Setyaningsih, R.; Pangastuti, A.

2018-03-01

Plastic is experiencing buildup in the environment. Biodegradation process can be used as an alternative for LDPE plastic degradation because the process is environmentally friendly. Some fungi of the genus Trichoderma are known to have a role in plastic biodegradation. This study aims to find out how the potential of that lignolytic Trichoderma spp. isolates in LDPE biodegradation. Five isolates were screened by growing on MSMB (mineral salt medium broth) emulsified LDPE powder, with 35 days incubation at 30°C and shaking at 80 rpm. TL1, TL4, and TL5 are the three most potential isolates, indicated by the growth marked by increasing colony size on screening media. They were then tested for biodegradability by growing the isolates in MSMA (mineral salt medium agar) which then inoculated by 4 sheets of sterile LDPE 1x3 cm2 above the colony surface, incubated for 5, 15, 25 and 35 days. The degredability assessment is done by measuring the weight loss of LDPE sheets after biodegradation treatment. The obtained degradability percentage of TL1, TL4, and TL5 are 4.87%, 7.12%, and 7,51% respectively. The visual micrograph of LDPE film by SEM showed the appearance of damage and unevenness on the surface of the post-degradation film.
Pengaruh Penambahan Kitosan dalam Pembuatan Biodegradable Foam Berbahan Baku Pati

Directory of Open Access Journals (Sweden)

Nanik Hendrawati

2017-05-01

Full Text Available Biodegradable foam is an alternative packaging to replace the expanded polystyrene foam packaging currently in use. Starch has been used to produce foam because of its low cost, low density, low toxicity, and biodegradability. Chitosan has been added to improve mechanical properties of product . The effect of variation on chitosan amount and starch types was investigated in this study. The amount of chitosan was varied as 0; 5; 10; 15; 20; 25; and 30 % w/w and starch types were used in this research were cassava, Corn and sago starch. Biodegradable foam was produced by using baking process method, all of material (Starch, Chitosan solution, Magnesium Stearate, Carrageenan, Glyserol, Protein Isolates dan polyvinil alcohol (PVOH were mixed with kitchen aid mixer. The mixture was poured into mold and heated in an oven at 125 oC for 1 hour. Then, foam was tested for its mechanical properties, water absorption and biodegradability and morphology (SEM. The results show that foam made from sago starch had lower water absortion than those made from cassava and corn starch. While, foam made from cassava starch was more biodegradable than the other foam. Biodegradable foam based sago starch and 30 % w/w of Chitosan adition gave the best performence in tensile stress that is 20 Mpa

Reactive electrospinning and biodegradation of cross-linked methacrylated polycarbonate nanofibers

Energy Technology Data Exchange (ETDEWEB)

Wu Ruizhi; Zhang Jianfeng; Fan Yuwei; Xu Xiaoming [Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, 1100 Florida Avenue, Box 137, New Orleans, LA 70119 (United States); Stoute, Diana; Lallier, Thomas, E-mail: xxu@lsuhsc.edu [Department of Cell Biology and Anatomy, Louisiana State University Health Science Center, 1100 Florida Avenue, Box 137, New Orleans, LA 70119 (United States)

2011-06-15

The objectives of this study were to fabricate cross-linked biodegradable polycarbonate nanofibers and to investigate their biodegradability by different enzymes. Poly(2,3-dihydroxycarbonate) was synthesized from naturally occurring l-tartaric acid. The hydroxyl groups on the functional polycarbonate were converted to methacrylate groups to enable the polymer to cross-link under UV irradiation. Smooth cross-linked methacrylated polycarbonate nanofibers (300-1800 nm) were fabricated by a reactive electrospinning process with in situ UV radiation from a mixed solution of linear methacrylated polycarbonate (MPC) and poly(ethylene oxide) (PEO) (MPC:PEO = 9:1) in methanol/chloroform (50/50). These cross-linked nanofibers have shown excellent solvent resistance and their solubility decreases with increasing degree of cross-linking. The thermal properties of linear and cross-linked polycarbonate nanofibers were investigated by differential scanning calorimetry and thermogravimetric analysis. The cross-linked polycarbonate nanofibers show no melting point below 200 {sup 0}C and their decomposition temperature increases with increasing cross-linking degree. Their biodegradation products by five different enzymes were analyzed using liquid chromatography-mass spectrometry (LC-MS). The biodegradability of the polycarbonate nanofibers decreases with increasing cross-linking degree. These nanofibers were found to support human fibroblast survival and to promote cell attachment. This study demonstrates that cross-linked biodegradable polycarbonate nanofibers with different chemical properties and biodegradability can be fabricated using the novel reactive electrospinning technology to meet the needs of different biomedical applications.
Modern mass spectrometry in the characterization and degradation of biodegradable polymers.

Science.gov (United States)

Rizzarelli, Paola; Carroccio, Sabrina

2014-01-15

In the last decades, the solid-waste management related to the extensively growing production of plastic materials, in concert with their durability, have stimulated increasing interest in biodegradable polymers. At present, a variety of biodegradable polymers has already been introduced onto the market and can now be competitive with non biodegradable thermoplastics in different fields (packaging, biomedical, textile, etc.). However, a significant economical effort is still directed in tailoring structural properties in order to further broaden the range of applications without impairing biodegradation. Improving the performance of biodegradable materials requires a good characterization of both physico-chemical and mechanical parameters. Polymer analysis can involve many different features including detailed characterization of chemical structures and compositions as well as average molecular mass determination. It is of outstanding importance in troubleshooting of a polymer manufacturing process and for quality control, especially in biomedical applications. This review describes recent trends in the structural characterization of biodegradable materials by modern mass spectrometry (MS). It provides an overview of the analytical tools used to evaluate their degradation. Several successful applications of MALDI-TOF MS (matrix assisted laser desorption ionization time of flight) and ESI MS (electrospray mass spectrometry) for the determination of the structural architecture of biodegradable macromolecules, including their topology, composition, chemical structure of the end groups have been reported. However, MS methodologies have been recently applied to evaluate the biodegradation of polymeric materials. ESI MS represents the most useful technique for characterizing water-soluble polymers possessing different end group structures, with the advantage of being easily interfaced with solution-based separation techniques such as high-performance liquid
Strategy on biological evaluation for biodegradable/absorbable materials and medical devices.

Science.gov (United States)

Liu, Chenghu; Luo, Hongyu; Wan, Min; Hou, Li; Wang, Xin; Shi, Yanping

2018-01-01

During the last two decades, biodegradable/absorbable materials which have many benefits over conventional implants are being sought in clinical practices. However, to date, it still remains obscure for us to perform full physic-chemical characterization and biological risk assessment for these materials and related devices due to their complex design and coherent processing. In this review, based on the art of knowledge for biodegradable/absorbable materials and biological risk assessment, we demonstrated some promising strategies to establish and improve the current biological evaluation systems for these biodegradable/absorbable materials and related medical devices.
The use of chromatographic indexes to study the biodegradation of crude oil in cold/icy seawater

International Nuclear Information System (INIS)

Siron, R.; Pelletier, E.

1993-01-01

A group of five protected mesocosms (3.5 m 3 each) was used to study the biodegradation of dispersed crude oil in cold and icy seawater. A wide range of oil concentrations was tested over four experiments lasting two weeks to six months. Various oil treatments were studied with respect to the natural bacterial degradation: chemically dispersed and untreated crude oil; and oil adsorbed on, and released from, an immersed substrate. The study was concerned with oil accommodated in the water column, accumulated in surface (sheens and emulsions), and collected in sediment traps. The oil biodegradation was assessed by means of the following gas chromatographic indexes: C17/pristane; C18/phytane; n-alkanes/isoprenoids; pristane/phytane; naphthalene/phenanthrene; 2-methyl naphthalene/1-methyl naphthalene; and methylnaphthalenes/total substituted naphthalenes. A combined index of biodegradation defined from the most significant hydrocarbon ratios is proposed to evaluate the overall biodegradation of dissolved compounds and oil droplets, involving both aliphatic and aromatic hydrocarbons. Coupled with mesocosm facilities, this approach appears very convenient to determine the potential degradability of crude oils by natural indigenous microflora. 26 refs., 11 figs., 2 tabs
Effect of cold drawing on mechanical properties of biodegradable fibers.

Science.gov (United States)

La Mantia, Francesco Paolo; Ceraulo, Manuela; Mistretta, Maria Chiara; Morreale, Marco

2017-01-26

Biodegradable polymers are currently gaining importance in several fields, because they allow mitigation of the impact on the environment related to disposal of traditional, nonbiodegradable polymers, as well as reducing the utilization of oil-based sources (when they also come from renewable resources). Fibers made of biodegradable polymers are of particular interest, though, it is not easy to obtain polymer fibers with suitable mechanical properties and to tailor these to the specific application. The main ways to tailor the mechanical properties of a given biodegradable polymer fiber are based on crystallinity and orientation control. However, crystallinity can only marginally be modified during processing, while orientation can be controlled, either during hot drawing or cold stretching. In this paper, a systematic investigation of the influence of cold stretching on the mechanical and thermomechanical properties of fibers prepared from different biodegradable polymer systems was carried out. Rheological and thermal characterization helped in interpreting the orientation mechanisms, also on the basis of the molecular structure of the polymer systems. It was found that cold drawing strongly improved the elastic modulus, tensile strength and thermomechanical resistance of the fibers, in comparison with hot-spun fibers. The elastic modulus showed higher increment rates in the biodegradable systems upon increasing the draw ratio.
Biodegradation of marine oil spill residues using aboriginal bacterial consortium based on Penglai 19-3 oil spill accident, China.

Science.gov (United States)

Wang, Chuanyuan; Liu, Xing; Guo, Jie; Lv, Yingchun; Li, Yuanwei

2018-09-15

Bioremediation, mainly by indigenous bacteria, has been regarded as an effective way to deal with the petroleum pollution after an oil spill accident. The biodegradation of crude oil by microorganisms co-incubated from sediments collected from the Penglai 19-3 oil platform, Bohai Sea, China, was examined. The relative susceptibility of the isomers of alkylnaphthalenes, alkylphenanthrenes and alkyldibenzothiophene to biodegradation was also discussed. The results showed that the relative degradation values of total petroleum hydrocarbon (TPH) are 43.56% and 51.29% for sediments with untreated microcosms (S-BR1) and surfactant-treated microcosms (S-BR2), respectively. TPH biodegradation results showed an obvious decrease in saturates (biodegradation rate: 67.85-77.29%) and a slight decrease in aromatics (biodegradation rate: 47.13-57.21%), while no significant difference of resins and asphaltenes was detected. The biodegradation efficiency of alkylnaphthalenes, alkylphenanthrenes and alkyldibenzothiophene for S-BR1 and S-BR2 samples reaches 1.28-84.43% and 42.56-86.67%, respectively. The efficiency of crude oil degradation in sediment with surfactant-treated microcosms cultures added Tween 20, was higher than that in sediment with untreated microcosms. The biodegradation and selective depletion is not only controlled by thermodynamics but also related to the stereochemical structure of individual isomer compounds. Information on the biodegradation of oil spill residues by the bacterial community revealed in this study will be useful in developing strategies for bioremediation of crude oil dispersed in the marine ecosystem. Copyright © 2018 Elsevier Inc. All rights reserved.
Aerobic Biodegradation Characteristic of Different Water-Soluble Azo Dyes

Directory of Open Access Journals (Sweden)

Shixiong Sheng

2017-12-01

Full Text Available This study investigated the biodegradation performance and characteristics of Sudan I and Acid Orange 7 (AO7 to improve the biological dye removal efficiency in wastewater and optimize the treatment process. The dyes with different water-solubility and similar molecular structure were biologically treated under aerobic condition in parallel continuous-flow mixed stirred reactors. The biophase analysis using microscopic examination suggested that the removal process of the two azo dyes is different. Removal of Sudan I was through biosorption, since it easily assembled and adsorbed on the surface of zoogloea due to its insolubility, while AO7 was biodegraded incompletely and bioconverted, the AO7 molecule was decomposed to benzene series and inorganic ions, since it could reach the interior area of zoogloea due to the low oxidation-reduction potential conditions and corresponding anaerobic microorganisms. The transformation of NH3-N, SO42− together with the presence of tryptophan-like components confirm that AO7 can be decomposed to non-toxic products in an aerobic bioreactor. This study provides a theoretical basis for the use of biosorption or biodegradation mechanisms for the treatment of different azo dyes in wastewater.
Design Considerations for Developing Biodegradable Magnesium Implants

Science.gov (United States)

Brar, Harpreet S.; Keselowsky, Benjamin G.; Sarntinoranont, Malisa; Manuel, Michele V.

The integration of biodegradable and bioabsorbable magnesium implants into the human body is a complex undertaking that faces major challenges. The complexity arises from the fact that biomaterials must meet both engineering and physiological requirements to ensure the desired properties. Historically, efforts have been focused on the behavior of commercial magnesium alloys in biological environments and their resultant effect on cell-mediated processes. Developing causal relationships between alloy chemistry and micro structure, and its effect on cellular behavior can be a difficult and time intensive process. A systems design approach driven by thermodynamics has the power to provide significant contributions in developing the next generation of magnesium alloy implants with controlled degradability, biocompatibility, and optimized mechanical properties, at reduced time and cost. This approach couples experimental research with theory and mechanistic modeling for the accelerated development of materials. The aim of this article is to enumerate this strategy, design considerations and hurdles for developing new magnesium alloys for use as biodegradable implant materials [1].
Biodegradation and chemical characterization of petroleum diesel hydrocarbons in seawater at low temperatures

OpenAIRE

Bausch, Alexandre Renee

2010-01-01

Master's thesis in Environmental engineering Petroleum hydrocarbons are a major source of marine contamination. Biodegradation, which is fundamental for the natural attenuation of these hydrocarbons in nature, involves mineralization or transformation of organic compounds by autochthonous microorganism communities. Various limiting factors characteristic of the petroleum, the external environment, and the microbial community determine the fate of oil (e.g., diesel) in the marine environmen...
Potential Signatures of Semi-volatile Compounds Associated With Nuclear Processing

Energy Technology Data Exchange (ETDEWEB)

Probasco, Kathleen M.; Birnbaum, Jerome C.; Maughan, A. D.

2002-06-01

Semi-volatile chemicals associated with nuclear processes (e.g., the reprocessing of uranium to produce plutonium for nuclear weapons, or the separation of actinides from processing waste streams), can provide sticky residues or signatures that will attach to piping, ducting, soil, water, or other surface media. Volatile compounds, that are more suitable for electro-optical sensing, have been well studied. However, the semi-volatile compounds have not been well documented or studied. A majority of these semi-volatile chemicals are more robust than typical gaseous or liquid chemicals and can have lifetimes of several weeks, months, or years in the environment. However, large data gaps exist concerning these potential signature compounds and more research is needed to fill these data gaps so that important signature information is not overlooked or discarded. This report investigates key semi-volatile compounds associated with nuclear separations, identifies available chemical and physical properties, and discusses the degradation products that would result from hydrolysis, radiolysis and oxidation reactions on these compounds.
Research of the biodegradability of degradable/biodegradable plastic material in various types of environments

Directory of Open Access Journals (Sweden)

Dana Adamcová

2017-04-01

Full Text Available Research was carried out in order to assess biodegradability of degradable/biodegradable materials made of HDPE and mixed with totally degradable plastic additive (TDPA additive or made of polyethylene (PE with the addition of pro-oxidant additive (d2w additive, advertised as 100% degradable or certifi ed as compostable within various types of environments. Research conditions were: (i controlled composting environment – laboratory-scale, (ii real composting conditions – domestic compost bin, (iii real composting conditions – industrial composting plant and (iv landfill conditions. The results demonstrate that the materials made of HDPE and mixed with totally degradable plastic additive (TDPA additive or made of polyethylene (PE with the addition of pro-oxidant additive (d2w additive or advertised as 100% degradable did not biodegrade in any of the above-described conditions and remained completely intact at the end of the tests. Biodegradation of the certified compostable plastic bags proceeded very well in laboratory-scale conditions and in real composting conditions – industrial composting plant, however, these materials did not biodegrade in real composting conditions – domestic compost bin and landfill conditions.
Are bioassays useful tools to assess redox processes and biodegradation?

DEFF Research Database (Denmark)

Albrechtsen, Hans-Jørgen; Pedersen, Philip Grinder; Ludvigsen, L.

2002-01-01

sensitive hydrochemical or geochemical parameters, levels of hydrogen, and redox potential. However, all these approaches have to be evaluated against TEAP-bioassays as the most direct measure. We assessed successfully ongoing microbial-mediated redox processes by TEAP-bioassays in degradation studies...... of aromatic and chlorinated aliphatic compounds in landfill leachate plumes, and of pesticides in aquifers with various redox conditions....
Biodegradation of bioplastics in natural environments.

Science.gov (United States)

Emadian, S Mehdi; Onay, Turgut T; Demirel, Burak

2017-01-01

The extensive production of conventional plastics and their use in different commercial applications poses a significant threat to both the fossil fuels sources and the environment. Alternatives called bioplastics evolved during development of renewable resources. Utilizing renewable resources like agricultural wastes (instead of petroleum sources) and their biodegradability in different environments enabled these polymers to be more easily acceptable than the conventional plastics. The biodegradability of bioplastics is highly affected by their physical and chemical structure. On the other hand, the environment in which they are located, plays a crucial role in their biodegradation. This review highlights the recent findings attributed to the biodegradation of bioplastics in various environments, environmental conditions, degree of biodegradation, including the identified bioplastic-degrading microorganisms from different microbial communities. Copyright © 2016 Elsevier Ltd. All rights reserved.
Biodegradation of benzalkonium chlorides singly and in mixtures by a Pseudomonas sp. isolated from returned activated sludge

Energy Technology Data Exchange (ETDEWEB)

Khan, Adnan Hossain, E-mail: akhan462@uwo.ca [Department of Chemical and Biochemical Engineering, University of Western Ontario, London, ON N6A 5B9 (Canada); Topp, Edward, E-mail: Ed.Topp@AGR.GC.CA [Agriculture and Agri-Food Canada, London, ON N5V 4T3 (Canada); Department of Biology, University of Western Ontario, London, ON N6A 5B7 (Canada); Scott, Andrew, E-mail: Andrew.Scott@AGR.GC.CA [Agriculture and Agri-Food Canada, London, ON N5V 4T3 (Canada); Sumarah, Mark, E-mail: Mark.Sumarah@agr.gc.ca [Agriculture and Agri-Food Canada, London, ON N5V 4T3 (Canada); Macfie, Sheila M., E-mail: smacfie@uwo.ca [Department of Biology, University of Western Ontario, London, ON N6A 5B7 (Canada); Ray, Madhumita B., E-mail: mbhowmic@uwo.ca [Department of Chemical and Biochemical Engineering, University of Western Ontario, London, ON N6A 5B9 (Canada)

2015-12-15

Highlights: • Pseudomonas sp. degraded two benzalkonium chlorides: BDDA and BDTA. • Although BDTA biodegraded at low concentration, it inhibited the degradation of BDDA. • For BDDA, two transformation products indicate two sites of bacterial activity. • {sup 14}C-labelled BDDA was mineralized to {sup 14}CO{sub 2} within 300 h. - Abstract: Bactericidal cationic surfactants such as quaternary ammonium compounds (QACs) are widely detected in the environment, and found at mg kg{sup −1} concentrations in biosolids. Although individual QACs are amenable to biodegradation, it is possible that persistence is increased for mixtures of QACs with varying structure. The present study evaluated the biodegradation of benzyl dimethyl dodecyl ammonium chloride (BDDA) singly and in the presence of benzyl dimethyl tetradecyl ammonium chloride (BDTA) using Pseudomonas sp., isolated from returned activated sludge. Growth was evaluated, as was biodegradation using {sup 14}C and HPLC-MS methods. BDTA was more toxic to growth of Pseudomonas sp. compared to BDDA, and BDTA inhibited BDDA biodegradation. The benzyl ring of [U-{sup 14}C-benzyl] BDDA was readily and completely mineralized. The detection of the transformation products benzyl methyl amine and dodecyl dimethyl amine in spent culture liquid was consistent with literature. Overall, this study demonstrates the antagonistic effect of interactions on biodegradation of two widely used QACs suggesting further investigation on the degradation of mixture of QACs in wastewater effluents and biosolids.
Utilization of Volatile Fatty Acids from Microalgae for the Production of High Added Value Compounds

Directory of Open Access Journals (Sweden)

Angelina Chalima

2017-10-01

Full Text Available Volatile Fatty Acids (VFA are small organic compounds that have attracted much attention lately, due to their use as a carbon source for microorganisms involved in the production of bioactive compounds, biodegradable materials and energy. Low cost production of VFA from different types of waste streams can occur via dark fermentation, offering a promising approach for the production of biofuels and biochemicals with simultaneous reduction of waste volume. VFA can be subsequently utilized in fermentation processes and efficiently transformed into bioactive compounds that can be used in the food and nutraceutical industry for the development of functional foods with scientifically sustained claims. Microalgae are oleaginous microorganisms that are able to grow in heterotrophic cultures supported by VFA as a carbon source and accumulate high amounts of valuable products, such as omega-3 fatty acids and exopolysaccharides. This article reviews the different types of waste streams in concert with their potential to produce VFA, the possible factors that affect the VFA production process and the utilization of the resulting VFA in microalgae fermentation processes. The biology of VFA utilization, the potential products and the downstream processes are discussed in detail.
A new application of passive samplers as indicators of in-situ biodegradation processes.

Science.gov (United States)

Belles, Angel; Alary, Claire; Criquet, Justine; Billon, Gabriel

2016-12-01

In this paper, a method for evaluating the in-situ degradation of nitro polycyclic aromatic hydrocarbons (nitro-PAH) in sediments is presented. The methodology is adapted from the passive sampler technique, which commonly uses the dissipation rate of labeled compounds loaded in passive sampler devices to sense the environmental conditions of exposure. In the present study, polymeric passive samplers (made of polyethylene strips) loaded with a set of labeled polycyclic aromatic hydrocarbons (PAH) and nitro-PAH were immersed in sediments (in field and laboratory conditions) to track the degradation processes. This approach is theoretically based on the fact that a degradation process induces a steeper concentration gradient of the labeled compounds in the surrounding sediment, thereby increasing their compound dissipation rates compared with their dissipation in abiotic conditions. Postulating that the degradation magnitude is the same for the labeled compounds loaded in polyethylene strips and for their native homologs that are potentially present in the sediment, the field degradation of 3 nitro-PAH (2-nitro-fluorene, 1-nitro-pyrene, 6-nitro-chrysene) was semi-quantitatively analyzed using the developed method. Copyright © 2016 Elsevier Ltd. All rights reserved.
Physical, mechanical, and biodegradable properties of meranti wood polymer composites

International Nuclear Information System (INIS)

Enamul Hoque, M.; Aminudin, M.A.M.; Jawaid, M.; Islam, M.S.; Saba, N.; Paridah, M.T.

2014-01-01

Highlights: • In-situ polymerization and solution casting method used to manufacture WPC. • In-situ WPC exhibited better properties compared to pure wood, 5% WPC and 20% WPC. • Lowest water absorption and least biodegradability shown by In-situ wood. - Abstract: In-situ polymerization and solution casting techniques are two effective methods to manufacture wood polymer composites (WPCs). In this study, wood polymer composites (WPCs) were manufactured from meranti sapwood by solution casting and in-situ polymerization process using methyl methacrylate (MMA) and epoxy matrix respectively. Physical, mechanical, and morphological characterizations of fabricated WPCs were then carried out to analyse their properties. Morphological properties of composites samples were analyzed through scanning electron microscopy (SEM). The result reveals that in-situ wood composite exhibited better properties compared to pure wood, 5% WPC and 20% WPC. Moreover, in-situ WPC had lowest water absorption and least biodegraded. Conversely, pure wood shown moderate mechanical strength, high biodegradation and water absorption rate. In term of biodegradation, earth-medium brought more severe effect than water in deteriorating the properties of the specimens
Kinetics of petroleum oil biodegradation by a consortium of three protozoan isolates (Aspidisca sp., Trachelophyllum sp. and Peranema sp.

Directory of Open Access Journals (Sweden)

L. Kachieng’a

2017-09-01

Full Text Available Petroleum oil is a complex mixture of substances, the majority of which are hydrocarbons; the latter represent an extremely important and heterogeneous group of compounds that find their way into water resources by anthropogenic or natural ways. The majority of toxic hydrocarbon components of petroleum are biodegradable, where bioremediation using microbial species has become an integral process for the restoration of oil-polluted areas. In this study, three bioremediation processes, namely natural attenuation, nutrient supplementation by adding glucose and biostimulation by adding Tween® 80, were carried out in various petroleum hydrocarbon concentrations in polluted water media using a consortium of three protozoan isolates (Aspidisca sp., Trachelophyllum sp. and Peranema sp.. A first-order kinetics model was fitted to the biodegradation data to evaluate the biodegradation rate and to determine the corresponding half-life time. First-order kinetics satisfactorily described the biodegradation of the petroleum-based contaminants under abiotic conditions. The results showed an increase in the percentage removal of petroleum oil at the lower petroleum concentrations and a gradual percentage decrease in removing petroleum oil residues occurred when there was an increase in the initial concentrations of the petroleum oil: 39%, 27%, 22%, 12%, 10% for various petroleum oil concentrations of 50, 100, 150, 200, 250 mg/L, respectively. A similar trend was also observed in the glucose-supplemented culture media where the reduction was 45% and 78% for petroleum concentrations of 250 mg/L and 50 mg/L, respectively. Biodegradation of between 33 and 90% was achieved at a Tween® 80 concentration of between 50 mg/L and 250 mg/L. The degradation rate constants for the natural attenuation process ranged between ≥0 to ≤0.50, ≥0 to ≤0.35, ≥0 to ≤0.25, ≥0 to ≤ 0.14 and ≥ 0 to ≤0.11 for petroleum oil concentrations varying from 50, 100, 150
Use of Respirometry To Determine the Effect of Nutrient Enhancement on JP-8 Biodegradability.

Science.gov (United States)

1995-11-27

present, environmental conditions, and certainly indigenous microbial communities present ( Atlas and Bartha , 1993). In general, biodegradation can be...Richard Bartha . Microbial Ecology : Fundementals and Applications. Redwood City, CA: The Benjamin Cummings Publishing Company, Inc, 1993. Autry...products caused by microorganisms or their enzymes ( Atlas and Bartha , 1993). It is greatly influenced by the nature and amount of the target compound
Biodegradation of flax fiber reinforced poly lactic acid

Directory of Open Access Journals (Sweden)

2010-07-01

Full Text Available Woven and nonwoven flax fiber reinforced poly lactic acid (PLA biocomposites were prepared with amphiphilic additives as accelerator for biodegradation. The prepared composites were buried in farmland soil for biodegradability studies. Loss in weight of the biodegraded composite samples was determined at different time intervals. The surface morphology of the biodegraded composites was studied with scanning electron microscope (SEM. Results indicated that in presence of mandelic acid, the composites showed accelerated biodegradation with 20–25% loss in weight after 50–60 days. On the other hand, in presence of dicumyl peroxide (as additive, biodegradation of the composites was relatively slow as confirmed by only 5–10% loss in weight even after 80–90 days. This was further confirmed by surface morphology of the biodegraded composites. We have attempted to show that depending on the end uses, we can add different amphiphilic additives for delayed or accelerated biodegradability. This work gives us the idea of biodegradation of materials from natural fiber reinforced PLA composites when discarded carelessly in the environment instead of proper waste disposal site.

Microbial ecology of methanogenic crude oil biodegradation; from microbial consortia to heavy oil

Energy Technology Data Exchange (ETDEWEB)

Head, Ian M.; Maguire, Michael J.; Sherry, Angela; Grant, Russell; Gray, Neil D.; Aitken, Carolyn M.; Martin Jones, D.; Oldenburg, Thomas B.P.; Larter, Stephen R. [Petroleum Research Group, Geosciences, University of Calgary (Canada)

2011-07-01

This paper presents the microbial ecology of methanogenic crude oil biodegradation. Biodegraded petroleum reservoirs are one of the most dramatic indications of the deep biosphere. It is estimated that heavy oil and oil sands will account for a considerable amount of energy production in the future. Carbon, a major resource for deep subsurface microorganisms, and energy are contained in large quantities in petroleum reservoirs. The aerobic to anaerobic paradigm shift is explained. A key process for in-situ oil biodegradation in petroleum reservoirs is methanogenesis. New paradigms for in-reservoir crude oil biodegradation are discussed. Variations in anaerobic degradation of crude oil hydrocarbons are also discussed. A graph shows the different patterns of crude oil biodegradation under sulfate-reducing and methanogenic conditions. Alternative anaerobic alkane activation mechanisms are also shown. From the study, it can be concluded that methanogenic crude oil degradation is of global importance and led to the establishment of the world's enormous heavy oil deposits.
Characteristics and Biodegradability of Wastewater Organic Matter in Municipal Wastewater Treatment Plants Collecting Domestic Wastewater and Industrial Discharge

Directory of Open Access Journals (Sweden)

Yun-Young Choi

2017-06-01

Full Text Available Municipal wastewater treatment plants (WWTPs in Korea collect and treat not only domestic wastewater, but also discharge from industrial complexes. However, some industrial discharges contain a large amount of non-biodegradable organic matter, which cannot be treated properly in a conventional biological WWTP. This study aimed to investigate the characteristics and biodegradability of the wastewater organic matter contained in the industrial discharges and to examine the fate of the industrial discharges in a biological WWTP. In contrast to most previous studies targeting a specific group of organic compounds or traditional water quality indices, such as biological oxygen demand (BOD and chemical oxygen demand (COD, this study was purposed to quantify and characterize the biodegradable and nonbiodegradable fractions of the wastewater organic matter. Chemical oxygen demand (COD fractionation tests and fluorescence spectroscopy revealed that the industrial discharge from dyeing or pulp mill factories contained more non-biodegradable soluble organic matter than did the domestic wastewater. Statistical analysis on the WWTPs’ monitoring data indicated that the industrial discharge containing non-biodegradable soluble organic matter was not treated effectively in a biological WWTP, but was escaping from the system. Thus, industrial discharge that contained non-biodegradable soluble organic matter was a major factor in the decrease in biodegradability of the discharge, affecting the ultimate fate of wastewater organic matter in a biological WWTP. Further application of COD fractionation and fluorescence spectroscopy to wastewaters, with various industrial discharges, will help scientists and engineers to better design and operate a biological WWTP, by understanding the fate of wastewater organic matter.
Biodegradable micromechanical sensors

DEFF Research Database (Denmark)

Keller, Stephan Sylvest; Greve, Anders; Schmid, Silvan

of mechanical and thermal properties of polymers. For example, measurements of the resonance frequency of cantilevers were used to characterize thin polymer coatings in various environmental conditions [2]. Also, the influence of humidity on the Young’s modulus of SU-8 was evaluated [3]. However, introduction...... (NIL). Second, we used spray-coating to deposit thin biodegradable films on microcantilevers. Both approaches allowed the determination of the Young’s modulus of the biopolymer. Furthermore, biodegradation by enzymes was investigated....
Biodegradation of thermoplastic starch/eggshell powder composites.

Science.gov (United States)

Bootklad, Munlika; Kaewtatip, Kaewta

2013-09-12

Thermoplastic starch (TPS) was prepared using compression molding and chicken eggshell was used as a filler. The effect of the eggshell powder (EP) on the properties of TPS was compared with the effect of commercial calcium carbonate (CC). The organic compound on the surface of the eggshell powder acted as a coupling agent that resulted in a strong adhesion between the eggshell powder and the TPS matrix, as confirmed by SEM micrographs. The biodegradation was determined by the soil burial test. The TPS/EP composites were more rapidly degraded than the TPS/CC composites. In addition, the eggshell powder improved the water resistance and thermal stability of the TPS. Copyright © 2013 Elsevier Ltd. All rights reserved.
PELÍCULAS BIODEGRADABLES BASADAS EN ALMIDÓN COMPOSIÇÃO E TRANSFORMAÇÃO DE FILMES BIODEGRADÁVEIS À BASE DE AMIDO COMPOSITION AND PROCESSING OF STARCH-BASED BIODEGRADABLE FILMS

Directory of Open Access Journals (Sweden)

MARIO ENRÍQUEZ C

2012-06-01

componentes mais comuns utilizados na elaboração de filmes biodegradáveis baseados em amido e os principais métodos de processamento para obtê-los.Starch is a promissory polymer to biodegradable films development for replacement traditional package materials due to it´s cheap, highly available and comes from natural resources. However, films made with starch only has limitations like poor mechanical properties, high vapor water permeability, retrogradation tendency, high rigidity, brittle, and others when compared to traditional synthetic films. To avoid these limitations is necessary to mix and blend starch with other substances with the aim of create filmogenic formulations and films like the synthetic ones. Below is a review made from patents and scientific articles complemented in which are listed more common components used for biodegradable starch-based films manufacturing and main processing methods.
Citrate biodegradation. Mid-year status report, [January 1994--June 1994

International Nuclear Information System (INIS)

Francis, A.J.; Dodge, C.J.; Chatterjee, S.; Landry, M.F.

1994-07-01

The Uranium Soils Integrated Demonstration (USID) Program was established to demonstrate advanced technologies for the remediation of uranium contaminated soils. This program, managed by the Fernald Environmental Restoration Management Corporation (FERMCO), focuses on the development and demonstration of new soil remediation processes which are faster, safer, and more economical for use at the Fernald site and throughout the DOE complex for cleanup of similar contaminants. Brookhaven National Laboratory (BNL) has developed a process which uses citric acid to treat contaminated soils and wastes with the subsequent recovery of toxic metals and uranium. Citric acid, a naturally occurring organic chelating agent, forms multidentate stable complexes with the transition metals and actinides, and has been effectively used to extract uranium and other metals from solid wastes via the formation of soluble metal citrate complexes. Further studies have also shown that several of the metal citrate complexes are readily biodegraded by microorganisms. During this process, the metals form a precipitate or become associated with the biomass and are recovered at the end of the biodegradation. Although uranyl citrate is recalcitrant to biodegradation, upon exposure to visible light it undergoes photochemical degradation resulting in the formation of an insoluble, stable polymeric form of uranium
Description, Properties, and Degradation of Selected Volatile Organic Compounds Detected in Ground Water--A Review of Selected Literature

Science.gov (United States)

Lawrence, Stephen J.

2006-01-01

This report provides abridged information describing the most salient properties and biodegradation of 27 chlorinated volatile organic compounds detected during ground-water studies in the United States. This information is condensed from an extensive list of reports, papers, and literature published by the U.S. Government, various State governments, and peer-reviewed journals. The list includes literature reviews, compilations, and summaries describing volatile organic compounds in ground water. This report cross-references common names and synonyms associated with volatile organic compounds with the naming conventions supported by the International Union of Pure and Applied Chemistry. In addition, the report describes basic physical characteristics of those compounds such as Henry's Law constant, water solubility, density, octanol-water partition (log Kow), and organic carbon partition (log Koc) coefficients. Descriptions and illustrations are provided for natural and laboratory biodegradation rates, chemical by-products, and degradation pathways.
Preparation and performance of Ecobras/bentonite biodegrading films; Preparacao e desempenho de filmes polimericos biodegradaveis a base de Ecobras e bentonita

Energy Technology Data Exchange (ETDEWEB)

Costa, Ana Nery M.; Melo, Nadja M.C.; Canedo, Eduardo L.; Carvalho, Laura H., E-mail: laura@dema.ufcg.edu.br [Unidade Academica de Engenharia de Materiais, Universidade Federal de Campina Grande (UAEMa/UFCG) Campina Grande, PB (Brazil); Araujo, Arthur R.A. [Felinto Industria e Comercio Ltda., Campina Grande, PB (Brazil)

2011-07-01

Compounds based on the biodegradable polymer Ecobras and bentonite clay in its pristine, sonicated, and organically modified with a quaternary ammonium salt forms were prepared as flat films. Clays and compounds were characterized by x-ray diffraction and scanning electron microscopy. Mechanical properties of the films were determined according to pertinent ASTM standards. Reasonable properties, higher than those of the matrix, were obtained with compounds prepared with purified clays and organoclays, particularly for low clay loading. (author)
Aerobic biodegradation potential of subsurface microorganisms from a jet fuel-contaminated aquifer

International Nuclear Information System (INIS)

Aelion, C.M.; Bradley, P.M.

1991-01-01

Current efforts to remediate subsurface contamination have spurred research in the application of in situ bioremediation. In 1975, a leak of 83,000 gallons (314,189 liters) of jet fuel (JP-4) contaminated a shallow water-table aquifer near North Charleston, S.C. Laboratory experiments were conducted with contaminated sediments to assess the aerobic biodegradation potential of the in situ microbial community. Sediments were incubated with 14 C-labeled organic compounds, and the evolution of 14 CO 2 was measured over time. Gas chromatographic analyses were used to monitor CO 2 production and O 2 consumption under aerobic conditions. Results indicated that the microbes from contaminated sediments remained active despite the potentially toxic effects of JP-4. 14 CO 2 was measured from [ 14 C]glucose respiration in unamended and nitrate-amended samples after 1 day of incubation. Total [ 14 C]glucose metabolism was greater in 1 mM nitrate-amended than in unamended samples because of increased cellular incorporation of 14 C label. [ 14 C]benzene and [ 14 C]toluene were not significantly respired after 3 months of incubation. With the addition of 1 mM NO 3 , CO 2 production measured by gas chromatographic analysis increased linearly during 2 months of incubation at a rte of 0.099 μmol g -1 (dry weight) day -1 while oxygen concentration decreased at a rate of 0.124 μmol g -1 (dry weight) day -1 . With no added nitrate, CO 2 production was not different from that in metabolically inhibited control vials. The results suggest that the in situ microbial community is active despite the JP-4 jet fuel contamination and that biodegradation may be compound specific. Also, the community is strongly nitrogen limited, and nitrogen additions may be required to significantly enhance hydrocarbon biodegradation
Containerless automated processing of intermetallic compounds and composites

Science.gov (United States)

Johnson, D. R.; Joslin, S. M.; Reviere, R. D.; Oliver, B. F.; Noebe, R. D.

1993-01-01

An automated containerless processing system has been developed to directionally solidify high temperature materials, intermetallic compounds, and intermetallic/metallic composites. The system incorporates a wide range of ultra-high purity chemical processing conditions. The utilization of image processing for automated control negates the need for temperature measurements for process control. The list of recent systems that have been processed includes Cr, Mo, Mn, Nb, Ni, Ti, V, and Zr containing aluminides. Possible uses of the system, process control approaches, and properties and structures of recently processed intermetallics are reviewed.
Kinetic study of the anaerobic biodegradation of alkyl polyglucosides and the influence of their structural parameters.

Science.gov (United States)

Ríos, Francisco; Fernández-Arteaga, Alejandro; Lechuga, Manuela; Jurado, Encarnación; Fernández-Serrano, Mercedes

2016-05-01

This paper reports a study of the anaerobic biodegradation of non-ionic surfactants alkyl polyglucosides applying the method by measurement of the biogas production in digested sludge. Three alkyl polyglucosides with different length alkyl chain and degree of polymerization of the glucose units were tested. The influence of their structural parameters was evaluated, and the characteristics parameters of the anaerobic biodegradation were determined. Results show that alkyl polyglucosides, at the standard initial concentration of 100 mgC L(-1), are not completely biodegradable in anaerobic conditions because they inhibit the biogas production. The alkyl polyglucoside having the shortest alkyl chain showed the fastest biodegradability and reached the higher percentage of final mineralization. The anaerobic process was well adjusted to a pseudo first-order equation using the carbon produced as gas during the test; also, kinetics parameters and a global rate constant for all the involved metabolic process were determined. This modeling is helpful to evaluate the biodegradation or the persistence of alkyl polyglucosides under anaerobic conditions in the environment and in the wastewater treatment.
Heat treatment of organics for increasing anaerobic biodegradability. Annual progress report, June 1, 1976-May 31, 1977. Civil engineering technical report No. 222

Energy Technology Data Exchange (ETDEWEB)

Healy, J.B. Jr.; Owen, W.F.; Stuckey, D.C.; Young, L.Y.; McCarty, P.L.

1977-06-30

This report represents the results of the first year of study on the heat treatment of organics to increase its biodegradability by anaerobic bacteria for the microbial production of methane. The purpose of this study is to develop a means for increasing the yield and reducing the cost of methane, a useful energy source. The procedures being evaluated are heat treatment at temperatures up to 250/sup 0/C, under pH ranges of 1 to 13. Included in this report are results on: (1) lignocellulose digestion and acclimation to its products from heat treatment; (2) the fate of waste activated sludge and its cellular nitrogenous compounds; and (3) the biodegradability of model compounds likely to be formed during heat treatment.
Calculating in situ degradation rates of hydrocarbon compounds in deep waters of the Gulf of Mexico.

Science.gov (United States)

Thessen, Anne E; North, Elizabeth W

2017-09-15

Biodegradation is an important process for hydrocarbon weathering that influences its fate and transport, yet little is known about in situ biodegradation rates of specific hydrocarbon compounds in the deep ocean. Using data collected in the Gulf of Mexico below 700m during and after the Deepwater Horizon oil spill, we calculated first-order degradation rate constants for 49 hydrocarbons and inferred degradation rate constants for an additional 5 data-deficient hydrocarbons. Resulting calculated (not inferred) half-lives of the hydrocarbons ranged from 0.4 to 36.5days. The fastest degrading hydrocarbons were toluene (k=-1.716), methylcyclohexane (k=-1.538), benzene (k=-1.333), and C1-naphthalene (k=-1.305). The slowest degrading hydrocarbons were the large straight-chain alkanes, C-26 through C-33 (k=-0.0494 through k=-0.007). Ratios of C-18 to phytane supported the hypothesis that the primary means of degradation in the subsurface was microbial biodegradation. These degradation rate constants can be used to improve models describing the fate and transport of hydrocarbons in the event of an accidental deep ocean oil spill. Copyright © 2017 Elsevier Ltd. All rights reserved.
Microbial Enzymatic Degradation of Biodegradable Plastics.

Science.gov (United States)

Roohi; Bano, Kulsoom; Kuddus, Mohammed; Zaheer, Mohammed R; Zia, Qamar; Khan, Mohammed F; Ashraf, Ghulam Md; Gupta, Anamika; Aliev, Gjumrakch

2017-01-01

The renewable feedstock derived biodegradable plastics are important in various industries such as packaging, agricultural, paper coating, garbage bags and biomedical implants. The increasing water and waste pollution due to the available decomposition methods of plastic degradation have led to the emergence of biodegradable plastics and biological degradation with microbial (bacteria and fungi) extracellular enzymes. The microbes utilize biodegradable polymers as the substrate under starvation and in unavailability of microbial nutrients. Microbial enzymatic degradation is suitable from bioremediation point of view as no waste accumulation occurs. It is important to understand the microbial interaction and mechanism involved in the enzymatic degradation of biodegradable plastics under the influence of several environmental factors such as applied pH, thermo-stability, substrate molecular weight and/or complexity. To study the surface erosion of polymer film is another approach for hydrolytic degradation characteristion. The degradation of biopolymer is associated with the production of low molecular weight monomer and generation of carbon dioxide, methane and water molecule. This review reported the degradation study of various existing biodegradable plastics along with the potent degrading microbes (bacteria and fungi). Patents available on plastic biodegradation with biotechnological significance is also summarized in this paper. This paper assesses that new disposal technique should be adopted for the degradation of polymers and further research is required for the economical production of biodegradable plastics along with their enzymatic degradation. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.
Modeling aerobic biodegradation in the capillary fringe.

Science.gov (United States)

Luo, Jian; Kurt, Zohre; Hou, Deyi; Spain, Jim C

2015-02-03

Vapor intrusion from volatile subsurface contaminants can be mitigated by aerobic biodegradation. Laboratory column studies with contaminant sources of chlorobenzene and a mixture of chlorobenzene, 1,2-dichlorobenzene, and 1,4-dichlorobenzene showed that contaminants were rapidly degraded in thin reactive zones with high biomass and low substrate concentrations in the vicinity of the capillary fringe. Such behavior was well characterized by a model that includes oxygen-, substrate-, and biomass-dependent biodegradation kinetics along with diffusive transport processes. An analytical solution was derived to provide theoretical support for the simplification of reaction kinetics and the approximation of reactive zone location and mass flux relationships at steady state. Results demonstrate the potential of aerobic natural attenuation in the capillary fringe for preventing contaminant migration in the unsaturated zone. The solution indicates that increasing contaminant mass flux into the column creates a thinner reactive zone and pushes it toward the oxygen boundary, resulting in a shorter distance to the oxygen source and a larger oxygen mass flux that balances the contaminant mass flux. As a consequence, the aerobic biodegradation can reduce high contaminant concentrations to low levels within the capillary fringe and unsaturated zone. The results are consistent with the observations of thin reactive layers at the interface in unsaturated zones. The model considers biomass while including biodegradation in the capillary fringe and unsaturated zone and clearly demonstrates that microbial communities capable of using the contaminants as electron donors may lead to instantaneous degradation kinetics in the capillary fringe and unsaturated zone.
Biodegradable Implants in Orthopaedics and Traumatology

OpenAIRE

YETKIN, Haluk

2014-01-01

Biodegradable implants are an alternative to metallic implants and have the advantage of not being necessary to remove once the fracture has healed. Twenty-two patients with fractures were treated with biodegradable implants. There were osteolysis in eleven patients; however, no serious complication was encountered. Although biodegradable implants are expensive, a second surgical procedure to remove the implants is not necessary, relieving the patient of the related costs and risks.
Anaerobic biodegradation of hexazinone in four sediments

International Nuclear Information System (INIS)

Wang Huili; Xu Shuxia; Tan Chengxia; Wang Xuedong

2009-01-01

Anaerobic biodegradation of hexazinone was investigated in four sediments (L1, L2, Y1 and Y2). Results showed that the L2 sediment had the highest biodegradation potential among four sediments. However, the Y1 and Y2 sediments had no capacity to biodegrade hexazinone. Sediments with rich total organic carbon, long-term contamination history by hexazinone and neutral pH may have a high biodegradation potential because the former two factors can induce the growth of microorganisms responsible for biodegradation and the third factor can offer suitable conditions for biodegradation. The addition of sulfate or nitrate as electron acceptors enhanced hexazinone degradation. As expected, the addition of electron donors (lactate, acetate or pyruvate) substantially inhibited the degradation. In natural environmental conditions, the effect of intermediate A [3-(4-hydroxycyclohexyl)-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H, 3H)dione] on anaerobic hexazinone degradation was negligible because of its low level.
Radiation processing of indigenous natural polymers. Properties of radiation modified blends from sago-starch for biodegradable composite

International Nuclear Information System (INIS)

Ghazali, Z.; Dahlan, K.Z.; Wongsuban, B.; Idris, S.; Muhammad, K.

2001-01-01

Research and development on biodegradable polymer blends and composites have gained wider interest to offer alternative eco-friendly products. Natural polysaccharide such as sago-starch offers the most promising raw material for the production of biodegradable composites. The potential of sago, which is so abundant in Malaysia, to produce blends for subsequent applications in composite material, was evaluated and explored. Blends with various formulations of sago starch and polyvinyl alcohol (PVA), and polyvinyl pyrrolidone (PVP) polymers were prepared and subjected to radiation modification using electron beam irradiation. The effect of irradiation on the sago and its blends was evaluated and their properties were characterized. The potential of producing composite from sago blends was explored. Foams from these blends were produced using microwave oven while films were produced through casting method. The properties such as mechanical, water absorption, expansion ratio, and biodegradability were characterized and reported in this paper. (author)
Radiation processing of indigenous natural polymers. Properties of radiation modified blends from sago-starch for biodegradable composite

Energy Technology Data Exchange (ETDEWEB)

Ghazali, Z.; Dahlan, K.Z. [Malaysian Institute for Nuclear and Technology Research (MINT), Bangi, Kajang (Malaysia); Wongsuban, B.; Idris, S.; Muhammad, K. [Universiti Putra Malaysia, Faculty of Food Science and Biotechnology, Department of Food Science, Serdang (Malaysia)

2001-03-01

Research and development on biodegradable polymer blends and composites have gained wider interest to offer alternative eco-friendly products. Natural polysaccharide such as sago-starch offers the most promising raw material for the production of biodegradable composites. The potential of sago, which is so abundant in Malaysia, to produce blends for subsequent applications in composite material, was evaluated and explored. Blends with various formulations of sago starch and polyvinyl alcohol (PVA), and polyvinyl pyrrolidone (PVP) polymers were prepared and subjected to radiation modification using electron beam irradiation. The effect of irradiation on the sago and its blends was evaluated and their properties were characterized. The potential of producing composite from sago blends was explored. Foams from these blends were produced using microwave oven while films were produced through casting method. The properties such as mechanical, water absorption, expansion ratio, and biodegradability were characterized and reported in this paper. (author)
The Analysis of a Microbial Community in the UV/O3-Anaerobic/Aerobic Integrated Process for Petrochemical Nanofiltration Concentrate (NFC Treatment by 454-Pyrosequencing.

Directory of Open Access Journals (Sweden)

Chao Wei

Full Text Available In this study, high-throughput pyrosequencing was applied on the analysis of the microbial community of activated sludge and biofilm in a lab-scale UV/O3- anaerobic/aerobic (A/O integrated process for the treatment of petrochemical nanofiltration concentrate (NFC wastewater. NFC is a type of saline wastewater with low biodegradability. From the anaerobic activated sludge (Sample A and aerobic biofilm (Sample O, 59,748 and 51,231 valid sequence reads were obtained, respectively. The dominant phylotypes related to the metabolism of organic compounds, polycyclic aromatic hydrocarbon (PAH biodegradation, assimilation of carbon from benzene, and the biodegradation of nitrogenous organic compounds were detected as genus Clostridium, genera Pseudomonas and Stenotrophomonas, class Betaproteobacteria, and genus Hyphomicrobium. Furthermore, the nitrite-oxidising bacteria Nitrospira, nitrite-reducing and sulphate-oxidising bacteria (NR-SRB Thioalkalivibrio were also detected. In the last twenty operational days, the total Chemical Oxygen Demand (COD and Total Organic Carbon (TOC removal efficiencies on average were 64.93% and 62.06%, respectively. The removal efficiencies of ammonia nitrogen and Total Nitrogen (TN on average were 90.51% and 75.11% during the entire treatment process.

The Analysis of a Microbial Community in the UV/O3-Anaerobic/Aerobic Integrated Process for Petrochemical Nanofiltration Concentrate (NFC) Treatment by 454-Pyrosequencing

Science.gov (United States)

Wei, Chao; He, Wenjie; Wei, Li; Li, Chunying; Ma, Jun

2015-01-01

In this study, high-throughput pyrosequencing was applied on the analysis of the microbial community of activated sludge and biofilm in a lab-scale UV/O3- anaerobic/aerobic (A/O) integrated process for the treatment of petrochemical nanofiltration concentrate (NFC) wastewater. NFC is a type of saline wastewater with low biodegradability. From the anaerobic activated sludge (Sample A) and aerobic biofilm (Sample O), 59,748 and 51,231 valid sequence reads were obtained, respectively. The dominant phylotypes related to the metabolism of organic compounds, polycyclic aromatic hydrocarbon (PAH) biodegradation, assimilation of carbon from benzene, and the biodegradation of nitrogenous organic compounds were detected as genus Clostridium, genera Pseudomonas and Stenotrophomonas, class Betaproteobacteria, and genus Hyphomicrobium. Furthermore, the nitrite-oxidising bacteria Nitrospira, nitrite-reducing and sulphate-oxidising bacteria (NR-SRB) Thioalkalivibrio were also detected. In the last twenty operational days, the total Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal efficiencies on average were 64.93% and 62.06%, respectively. The removal efficiencies of ammonia nitrogen and Total Nitrogen (TN) on average were 90.51% and 75.11% during the entire treatment process. PMID:26461260
Biodegradation of tert-butylphenyl diphenyl phosphate

International Nuclear Information System (INIS)

Heitkamp, M.A.; Freeman, J.P.; Cerniglia, C.E.

1986-01-01

The biodegradation of tert-butylphenyl diphenyl phosphate (BPDP) was examined in microcosms containing sediment and water from five different ecosystems as part of studies to elucidate the environmental fate of phosphate ester flame retardants. Biodegradation of [ 14 C]BPDP was monitored in the environmental microcosms by measuring the evolution of 14 CO 2 . Over 37% of BPDP was mineralized after 8 weeks in microcosms from an ecosystem which had chronic exposure to agricultural chemicals. In contrast, only 1.7% of BPDP was degraded to 14 CO 2 in samples collected from a noncontaminated site. The exposure concentration of BPDP affected the percentage which was degraded to 14 CO 2 in microcosms from the two most active ecosystems. Mineralization was highest at a concentration of 0.1 mg of BPDP and was inhibited with 10- and 100-fold higher concentrations of BPDP. The authors observed adaptive increases in both microbial populations and phosphoesterase enzymes in some sediments acclimated to BPDP. Chemical analyses of the residues in the microcosms indicated undegraded BPDP and minor amounts of phenol, tert-butylphenol, diphenyl phosphate, and triphenyl phosphate as biodegradation products. These data suggest that the microbial degradation of BPDP results from at least three catabolic processes and is highest when low concentrations of BPDP are exposed to sediment microorganisms of eutrophic ecosystems which have high phosphotri- and diesterase activities and previous exposure to anthropogenic chemicals
Biodegradable and compostable alternatives to conventional plastics

Science.gov (United States)

Song, J. H.; Murphy, R. J.; Narayan, R.; Davies, G. B. H.

2009-01-01

Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers. The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all ‘good’ or petrochemical-based products are all ‘bad’. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemical-based counterparts. Specific examples are given from new research on biodegradability in simulated ‘home’ composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted. PMID:19528060
Biodegradable and compostable alternatives to conventional plastics.

Science.gov (United States)

Song, J H; Murphy, R J; Narayan, R; Davies, G B H

2009-07-27

Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers. The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all 'good' or petrochemical-based products are all 'bad'. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemical-based counterparts. Specific examples are given from new research on biodegradability in simulated 'home' composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted.
Elaboration of an experimental method to assess biodegradation agents: Bioremediation trials on oil polluted beach

International Nuclear Information System (INIS)

Merlin, F.X.; Guerroue, P.L.; Quere, C.; Chaumery, C.J.; Oudot, J.

1992-01-01

Trials were conducted on a sheltered beach in Brittany, France, in order to define a methodology to control and assess biotreatment of oil polluted shores. Six test plots of 3 m 2 each were prepared, each enclosed by a wall to protect the plot from extensive wave action. Light crude was applied to each plot at a total concentration of 5 l/m 2 in two consecutive applications. Four different bioremediation processes were evaluated, involving the application of microflora specifically adapted to oil degradation, adapted dehydrated bacteria, nutritive nitrogen and phosphorus, and chalk powder. The evaluation included microbiological analyses, measurements of oil concentration in the sediment, and qualitative analysis of the oil. Under the test conditions, the oil biodegradation in surface sediment took place very slowly and the disappearance of oil was mainly due to tidal and wave action. The main factor limiting biodegradation is the availability of nitrogen. Only the second and third of the above four processes were able to show a slight increase in oil biodegradation. The amount of oil biodegraded by those processes was estimated at about 20%. 9 refs., 11 figs., 5 tabs
Assessing microbial degradation of o-xylene at field-scale from the reduction in mass flow rate combined with compound-specific isotope analyses

Science.gov (United States)

Peter, A.; Steinbach, A.; Liedl, R.; Ptak, T.; Michaelis, W.; Teutsch, G.

2004-07-01

In recent years, natural attenuation (NA) has evolved into a possible remediation alternative, especially in the case of BTEX spills. In order to be approved by the regulators, biodegradation needs to be demonstrated which requires efficient site investigation and monitoring tools. Three methods—the Integral Groundwater Investigation method, the compound-specific isotope analysis (CSIA) and a newly developed combination of both—were used in this work to quantify at field scale the biodegradation of o-xylene at a former gasworks site which is heavily contaminated with BTEX and PAHs. First, the Integral Groundwater Investigation method [Schwarz, R., Ptak, T., Holder, T., Teutsch, G., 1998. Groundwater risk assessment at contaminated sites: a new investigation approach. In: Herbert, M. and Kovar, K. (Editors), GQ'98 Groundwater Quality: Remediation and Protection. IAHS Publication 250, pp. 68-71; COH 4 (2000) 170] was applied, which allows the determination of mass flow rates of o-xylene by integral pumping tests. Concentration time series obtained during pumping at two wells were used to calculate inversely contaminant mass flow rates at the two control planes that are defined by the diameter of the maximum isochrone. A reactive transport model was used within a Monte Carlo approach to identify biodegradation as the dominant process for reduction in the contaminant mass flow rate between the two consecutive control planes. Secondly, compound-specific carbon isotope analyses of o-xylene were performed on the basis of point-scale samples from the same two wells. The Rayleigh equation was used to quantify the degree of biodegradation that occurred between the wells. Thirdly, a combination of the Integral Groundwater Investigation method and the compound-specific isotope analysis was developed and applied. It comprises isotope measurements during the integral pumping tests and the evaluation of δ13C time series by an inversion algorithm to obtain spatially
40 CFR Figure 1 to Subpart G of... - Definitions of Terms Used in Wastewater Equations

Science.gov (United States)

2010-07-01

... Chemical Manufacturing Industry for Process Vents, Storage Vessels, Transfer Operations, and Wastewater Pt...-specific fraction of Table 8 and/or Table 9 compounds biodegraded, unitless. fbio=Site-specific fraction of an individual Table 8 or Table 9 compound biodegraded, unitless. Fm=Compound-specific fraction...
Personal Review: Progress and prospect in electro-Fenton process for wastewater treatment

Institute of Scientific and Technical Information of China (English)

JIANG Cheng-chun; ZHANG Jia-fa

2007-01-01

As a novel advanced oxidation process (AOP), electro-Fenton process is powerful for degrading most organic compounds including toxic and non-biodegradable ones, and so has attracted great attention. This paper reviews this process in detail including the mechanism, electrolytic bath, electrode materials, aerations and operation parameters. The application of electro-Fenton method in wastewater treatment is evaluated and summarized. Future work in this field is suggested, and three main directions of new electrode exploitation, development of assisted technologies and mechanistic study should be strengthened.
Evaluation of biodegradation of bionanocomposites of PHB/PP-g-MA/vermiculite

International Nuclear Information System (INIS)

Mesquita, P.J.P. de; Alves, T.S.; Barbosa, R.; Andrade, D. de L.A.C.S.

2014-01-01

In this work, we evaluated the process of biodegradation of PHB bionanocomposites/PP-g-MA/clay. Films were prepared with compositions of 5% PP-g-MA and 3% clay (BIO5); and 2.5% PP-g-MA and 3% clay (BIO2.5). The biodegradation test was conducted according to ASTM G 160-03 for a period of 86 days. The evaluation of biodegradation was performed by optical microscopy (MO), loss of mass, FTIR and XRD. The bionanocomposites presented change of coloration and appearance of fissures. As for loss in mass in the system presented loss of BIO2,5 22.5% and 25.9% BIO5, for 86 days of simulated soil exposure. We also observed by FTIR sharp reduction in intensity of the band corresponding to the C = O groups, indicating that the microbial attack promoted cleavage of the ester group links. By XRD, reduction in the intensity of the peaks and enlargements of the same with increasing exposure time, proving the biodegradation behavior of bionanocomposites. (author)
A process for producing lignin and volatile compounds from hydrolysis liquor.

Science.gov (United States)

Khazraie, Tooran; Zhang, Yiqian; Tarasov, Dmitry; Gao, Weijue; Price, Jacquelyn; DeMartini, Nikolai; Hupa, Leena; Fatehi, Pedram

2017-01-01

Hot water hydrolysis process is commercially applied for treating wood chips prior to pulping or wood pellet production, while it produces hydrolysis liquor as a by-product. Since the hydrolysis liquor is dilute, the production of value-added materials from it would be challenging. In this study, acidification was proposed as a viable method to extract (1) furfural and acetic acid from hot water hydrolysis liquor and (2) lignin compounds from the liquor. The thermal properties of the precipitates made from the acidification of hydrolysis liquor confirmed the volatile characteristics of precipitates. Membrane dialysis was effective in removing inorganic salts associated with lignin compounds. The purified lignin compounds had a glass transition temperature (Tg) of 180-190 °C, and were thermally stable. The results confirmed that lignin compounds present in hot water hydrolysis liquor had different characteristics. The acidification of hydrolysis liquor primarily removed the volatile compounds from hydrolysis liquor. Based on these results, a process for producing purified lignin and precipitates of volatile compounds was proposed.
Biodegradation of a surrogate naphthenic acid under denitrifying conditions.

Science.gov (United States)

Gunawan, Yetty; Nemati, Mehdi; Dalai, Ajay

2014-03-15

Extraction of bitumen from the shallow oil sands generates extremely large volumes of waters contaminated by naphthenic acid which pose severe environmental and ecological risks. Aerobic biodegradation of NA in properly designed bioreactors has been investigated in our earlier works. In the present work, anoxic biodegradation of trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA) coupled to denitrification was investigated as a potential ex situ approach for the treatment of oil sand process waters in bioreactors whereby excessive aeration cost could be eliminated, or as an in situ alternative for the treatment of these waters in anoxic stabilization ponds amended with nitrate. Using batch and continuous reactors (CSTR and biofilm), effects of NA concentration (100-750mgL(-1)), NA loading rate (up to 2607.9mgL(-1)h(-1)) and temperature (10-35°C) on biodegradation and denitrification processes were evaluated. In the batch system biodegradation of trans-4MCHCA coupled to denitrification occurred even at the highest concentration of 750mgL(-1). Consistent with the patterns reported for aerobic biodegradation, increase in initial concentration of NA led to higher biodegradation and denitrification rates and the optimum temperature was determined as 23-24°C. In the CSTR, NA removal and nitrate reduction rates passed through a maximum due to increases in NA loading rate. NA loading rate of 157.8mgL(-1)h(-1) at which maximum anoxic NA and nitrate removal rates (105.3mgL(-1)h(-1) and 144.5mgL(-1)h(-1), respectively) occurred was much higher than those reported for the aerobic alternative (NA loading and removal rates: 14.2 and 9.6mgL(-1)h(-1), respectively). In the anoxic biofilm reactor removal rates of NA and nitrate were dependent on NA loading rate in a linear fashion for the entire range of applied loading rates. The highest loading and removal rates for NA were 2607.9 and 2028.1mgL(-1)h(-1), respectively which were at least twofold higher than the values
Process for uranium recovery in phosphorus compounds

International Nuclear Information System (INIS)

Demarthe, J.M.; Solar, Serge.

1980-01-01

Process for uranium recovery in phosphorus compounds with an organic phase containing a dialkylphosphoric acid. A solubilizing agent constituted of an heavy alcohol or a phosphoric acid ester or a tertiary phosphine oxide or octanol-2, is added to the organic phase for solubilization of the uranium and ammonium dialkyl pyrophosphate [fr
Improving the Corrosion Resistance of Biodegradable Magnesium Alloys by Diffusion Coating Process

Science.gov (United States)

Levy, Galit Katarivas; Aghion, Eli

Magnesium alloys suffer from accelerated corrosion in physiological environment and hence their use as a structural material for biodegradable implants is limited. The present study focuses on a diffusion coating treatment that amplifies the beneficial effect of Neodymium on the corrosion resistance of magnesium alloys. The diffusion coating layer was obtained by applying 1 µm Nd coating on EW10X04 magnesium alloy using Electron-gun evaporator and PVD process. The coated alloy was heat treated at 350°C for 3 hours in a protective atmosphere of N2+0.2%SF6. The micro structure characteristics were evaluated by SEM, XRD, and XPS; the corrosion resistance was examined by potentiodynamic polarization and EIS analysis. The corrosion resistance of the diffusion coated alloy was significantly improved compared to the uncoated material. This was related to: (i) formation of Nd2O3 in the outer scale, (ii) integration of Nd in the MgO oxide layer, and (iii) formation of secondary phase Mg41Nd5 along the grain boundaries of α-Mg.
Biodegradation of polycyclic aromatic hydrocarbons in rhizosphere soil

Energy Technology Data Exchange (ETDEWEB)

Schwab, A.P.; Banks, M.K.; Arunachalam, M. [Kansas State Univ., Manhattan, KS (United States)

1995-12-31

Increased contaminant biodegradation in soil in the presence of plants has been demonstrated for several classes of organic compounds. Although enhanced dissipation of polycyclic aromatic hydrocarbons (PAHs) was observed previously in the rhizosphere of several plant species, the mechanism of this effect has not been assessed. A laboratory experiment was conducted to test the importance of cometabolism and the presence of common rhizosphere organic acids on the loss of PAHs (pyrene and phenanthrene) from soil. The role of cometabolism in the mineralization of pyrene was tested by observing the impact of adding phenanthrene to soil containing {sup 14}C-pyrene and observing the effects on {sup 14}CO{sub 2} generation. Adding phenanthrene apparently induced cometabolism of pyrene, particularly in the presence of organic acids. In a subsequent experiment, mineralization of pyrene to {sup 14}CO{sub 2} was significantly greater in soil from the rhizospheres of warm-season grasses, sorghum (Sorghum bicolor L.) and bermuda grass (Cynodon dactylon L.), compared to soil from alfalfa (Medicago sativa L.), which did not differ from sterilized control soil. A highly branched, fine root system appears to be more effective in enhancing biodegradation than taproots, and the presence of organic acids increases rates of PAH mineralization.
[Biodegradation of methyl tert-butyl ether by stabilized immobilized Methylibium petroleiphilum PM1 cells and its biodegradation kinetics analysis].

Science.gov (United States)

Cheng, Zhuo-wei; Fu, Ling-xiao; Jiang, Yi-feng; Chen, Jian-meng; Zhang, Rong

2011-05-01

Methylibium petroleiphilum PM1, which is capable of degrading methyl tert-butyl ether (MTBE) , was immobilized in calcium alginate gel beads. Several methods were explored to increase the strength of these gel beads. The central composite design analysis indicated that the introduction of 0.2 mol x L(-1) Ca2+ into the crosslinking solution, 1.38 mmol x L(-1) Ca2+ into the growth medium and 0.1% polyethyleneimine (PEI) as the chemical crosslinking agent could increase the stability of the Ca-alginate gel beads with no loss of biodegradation activity. The stabilized immobilized cells could be used 400 h continuously with no breakage and no bioactivity loss. Examination of scanning electron microscope demonstrated that a membrane surrounding the gel beads was formed and the cells could grow and breed well in the stabilized calcium alginate gel beads. Kinetic analysis of the gel bead-degradation indicated that the rate-limiting step was biochemical process instead of intraparticle diffusion process. The diameter of 3 mm affected the biodegradability less while high concentration of PEI induced much more serious mass transfer restraint.
Numerical study on injection parameters optimization of thin wall and biodegradable polymers parts

Science.gov (United States)

Santos, C.; Mendes, A.; Carreira, P.; Mateus, A.; Malça, C.

2017-07-01

Nowadays, the molds industry searches new markets, with diversified and added value products. The concept associated to the production of thin walled and biodegradable parts mostly manufactured by injection process has assumed a relevant importance due to environmental and economic factors. The growth of a global consciousness about the harmful effects of the conventional polymers in our life quality associated with the legislation imposed, become key factors for the choice of a particular product by the consumer. The target of this work is to provide an integrated solution for the injection of parts with thin walls and manufactured using biodegradable materials. This integrated solution includes the design and manufacture processes of the mold as well as to find the optimum values for the injection parameters in order to become the process effective and competitive. For this, the Moldflow software was used. It was demonstrated that this computational tool provides an effective responsiveness and it can constitute an important tool in supporting the injection molding of thin-walled and biodegradable parts.
Biodegradation of petroleum hydrocarbons in seawater at low temperatures (0-5 degrees C) and bacterial communities associated with degradation.

Science.gov (United States)

Brakstad, Odd G; Bonaunet, Kristin

2006-02-01

In this study biodegradation of hydrocarbons in thin oil films was investigated in seawater at low temperatures, 0 and 5 degrees C. Heterotrophic (HM) or oil-degrading (ODM) microorganisms enriched at the two temperatures showed 16S rRNA sequence similarities to several bacteria of Arctic or Antarctic origin. Biodegradation experiments were conducted with a crude mineral oil immobilized as thin films on hydrophobic Fluortex adsorbents in nutrient-enriched or sterile seawater. Chemical and respirometric analysis of hydrocarbon depletion showed that naphthalene and other small aromatic hydrocarbons (HCs) were primarily biodegraded after dissolution to the water phase, while biodegradation of larger polyaromatic hydrocarbons (PAH) and C(10)-C(36) n-alkanes, including n-hexadecane, was associated primarily with the oil films. Biodegradation of PAH and n-alkanes was significant at both 0 and 5 degrees C, but was decreased for several compounds at the lower temperature. n-Hexadecane biodegradation at the two temperatures was comparable at the end of the experiments, but was delayed at 0 degree C. Investigations of bacterial communities in seawater and on adsorbents by PCR amplification of 16S rRNA gene fragments and DGGE analysis indicated that predominant bacteria in the seawater gradually adhered to the oil-coated adsorbents during biodegradation at both temperatures. Sequence analysis of most DGGE bands aligned to members of the phyla Proteobacteria (Gammaproteobacteria) or Bacteroidetes. Most sequences from experiments at 0 degree C revealed affiliations to members of Arctic or Antarctic consortia, while no such homology was detected for sequences from degradation experiment run at 5 degrees C. In conclusion, marine microbial communities from cold seawater have potentials for oil film HC degradation at temperatures < or =5 degrees C, and psychrotrophic or psychrophilic bacteria may play an important role during oil HC biodegradation in seawater close to freezing
PGDP Trichloroethene Biodegradation Investigation Summary Report: Regional Gravel Aquifer & Northwest Plume

Energy Technology Data Exchange (ETDEWEB)

Hampson, Steve [Univ. of Kentucky, Lexington, KY (United States). Kentucky Research Consortium for Energy and Environment

2008-09-01

The evaluation of biological degradation processes addressed by this report are part of a broad trichloroethene (TCE) Fate and Transport Investigation that includes four (4) topics of phased investigation (Table ES1) relative to degradation and/or attenuation of TCE in the Regional Gravel Aquifer (RGA) underlying the United States Department of Energy Paducah Gaseous Diffusion Plant (PGDP). In order of implementation the project phases are: (1) derivation of a TCE first-order rate constant by normalization of TCE values against technetium-99 (⁹⁹Tc) and chloride. 2) identification of the presence of microbes capable of aerobic co-metabolic TCE biodegradation using enzyme activity probes (this report); 3) Compound-specific isotope analysis (CSIA) to support prevalence of biotic and/or abiotic degradation processes; and 4) evaluation of potential abiotic RGA-TCE attenuation mechanisms including sorption. This report summarizes the Phase II activities related to the identification and evaluation of biological degradation processes that may be actively influencing TCE fate and transport in the RGA contaminant plumes at the United States Department of Energy (DOE) PGDP and its environs (Figure ES1). The goals of these activities were to identify active biological degradation mechanisms in the RGA through multiple lines of evidence and to provide DOE with recommendations for future TCE biological degradation investigations.
Microorganisms hydrolyse amide bonds; knowledge enabling read-across of biodegradability of fatty acid amides.

Science.gov (United States)

Geerts, Roy; Kuijer, Patrick; van Ginkel, Cornelis G; Plugge, Caroline M

2014-07-01

To get insight in the biodegradation and potential read-across of fatty acid amides, N-[3-(dimethylamino)propyl] cocoamide and N-(1-ethylpiperazine) tall oil amide were used as model compounds. Two bacteria, Pseudomonas aeruginosa PK1 and Pseudomonas putida PK2 were isolated with N-[3-(dimethylamino)propyl] cocoamide and its hydrolysis product N,N-dimethyl-1,3-propanediamine, respectively. In mixed culture, both strains accomplished complete mineralization of N-[3-(dimethylamino)propyl] cocoamide. Aeromonas hydrophila PK3 was enriched with N-(1-ethylpiperazine) tall oil amide and subsequently isolated using agar plates containing dodecanoate. N-(2-Aminoethyl)piperazine, the hydrolysis product of N-(1-ethylpiperazine) tall oil amide, was not degraded. The aerobic biodegradation pathway for primary and secondary fatty acid amides of P. aeruginosa and A. hydrophila involved initial hydrolysis of the amide bond producing ammonium, or amines, where the fatty acids formed were immediately metabolized. Complete mineralization of secondary fatty acid amides depended on the biodegradability of the released amine. Tertiary fatty acid amides were not transformed by P. aeruginosa or A. hydrophila. These strains were able to utilize all tested primary and secondary fatty acid amides independent of the amine structure and fatty acid. Read-across of previous reported ready biodegradability results of primary and secondary fatty acid amides is justified based on the broad substrate specificity and the initial hydrolytic attack of the two isolates PK1 and PK3.
Here today, gone tomorrow: biodegradable soft robots

Science.gov (United States)

Rossiter, Jonathan; Winfield, Jonathan; Ieropoulos, Ioannis

2016-04-01

One of the greatest challenges to modern technologies is what to do with them when they go irreparably wrong or come to the end of their productive lives. The convention, since the development of modern civilisation, is to discard a broken item and then procure a new one. In the 20th century enlightened environmentalists campaigned for recycling and reuse (R and R). R and R has continued to be an important part of new technology development, but there is still a huge problem of non-recyclable materials being dumped into landfill and being discarded in the environment. The challenge is even greater for robotics, a field which will impact on all aspects of our lives, where discards include motors, rigid elements and toxic power supplies and batteries. One novel solution is the biodegradable robot, an active physical machine that is composed of biodegradable materials and which degrades to nothing when released into the environment. In this paper we examine the potential and realities of biodegradable robotics, consider novel solutions to core components such as sensors, actuators and energy scavenging, and give examples of biodegradable robotics fabricated from everyday, and not so common, biodegradable electroactive materials. The realisation of truly biodegradable robots also brings entirely new deployment, exploration and bio-remediation capabilities: why track and recover a few large non-biodegradable robots when you could speculatively release millions of biodegradable robots instead? We will consider some of these exciting developments and explore the future of this new field.

Biodegradable Paper Sheeting as Agricultural Covering with Incorporation of Bamboo Pulp Sludge

Directory of Open Access Journals (Sweden)

Chuan-Gui Wang

2014-05-01

Full Text Available This paper reports the manufacturing process for biodegradable paper sheeting with incorporation of bamboo paper sludge, fibers of poplar woods, and viscose fibers by wet-laid nonwoven technology. The best process conditions included a basis weight of 30 g/m2, a bamboo paper sludge content of 10 wt%, and a polyvinyl alcohol concentration of 4 wt%. The burst strength, tearing resistance, tensile properties, resistance to water, and degradation rate were 220.65 kPa, 60.00 N, 46.10 N, 153 Pa, and 56.18%, respectively, under the best process conditions. The biodegradable paper sheeting can satisfy the demand for replacement of agricultural plastic sheeting used for such purposes as moisture retention of soil and promotion of plant growth.
Physicochemical treatments of anionic surfactants wastewater: Effect on aerobic biodegradability.

Science.gov (United States)

Aloui, Fathi; Kchaou, Sonia; Sayadi, Sami

2009-05-15

The effect of different physicochemical treatments on the aerobic biodegradability of an industrial wastewater resulting from a cosmetic industry has been investigated. This industrial wastewater contains 11423 and 3148mgL(-1) of chemical oxygen demand (COD) and anionic surfactants, respectively. The concentration of COD and anionic surfactants were followed throughout the diverse physicochemical treatments and biodegradation experiments. Different pretreatments of this industrial wastewater using chemical flocculation process with lime and aluminium sulphate (alum), and also advanced oxidation process (electro-coagulation (Fe and Al) and electro-Fenton) led to important COD and anionic surfactants removals. The best results were obtained using electro-Fenton process, exceeding 98 and 80% of anionic surfactants and COD removals, respectively. The biological treatment by an isolated strain Citrobacter braakii of the surfactant wastewater, as well as the pretreated wastewater by the various physicochemical processes used in this study showed that the best results were obtained with electro-Fenton pretreated wastewater. The characterization of the treated surfactant wastewater by the integrated process (electro-coagulation or electro-Fenton)-biological showed that it respects Tunisian discharge standards.
Application of passive dosing to study the biotransformation and biodegradation of hydrophobic compounds

DEFF Research Database (Denmark)

Smith, E. C.; Rein, Arno; Trapp, Stefan

2011-01-01

Achieving well-defined and constant dissolved concentrations of hydrophobic compounds is challenging due to volatilization or sorptive losses. With passive dosing, continual partitioning into the test medium of compound(s) loaded in a polymer compensates for losses, and provides defined and const...
Assessment of MTBE biodegradation in contaminated groundwater using 13C and 14C analysis: Field and laboratory microcosm studies

International Nuclear Information System (INIS)

Thornton, Steven F.; Bottrell, Simon H.; Spence, Keith H.; Pickup, Roger; Spence, Michael J.; Shah, Nadeem; Mallinson, Helen E.H.; Richnow, Hans H.

2011-01-01

Highlights: → Carbon isotope fractionation for MTBE varies with dissolved oxygen concentration. → Carbon isotope fractionation can underestimate MTBE biodegradation at plume fringes. → Fractionation factors must be for specific biodegradation mechanisms and conditions. → Specific microbial populations influence carbon isotope fractionation in groundwater. - Abstract: Radiolabelled assays and compound-specific stable isotope analysis (CSIA) were used to assess methyl tert-butyl ether (MTBE) biodegradation in an unleaded fuel plume in a UK chalk aquifer, both in the field and in laboratory microcosm experiments. The 14 C-MTBE radiorespirometry studies demonstrated widespread potential for aerobic and anaerobic MTBE biodegradation in the aquifer. However, δ 13 C compositions of MTBE in groundwater samples from the plume showed no significant 13 C enrichment that would indicate MTBE biodegradation at the field scale. Carbon isotope enrichment during MTBE biodegradation was assessed in the microcosms when dissolved O 2 was not limiting, compared with low in situ concentrations (2 mg/L) in the aquifer, and in the absence of O 2 . The microcosm experiments showed ubiquitous potential for aerobic MTBE biodegradation in the aquifer within hundreds of days. Aerobic MTBE biodegradation in the microcosms produced an enrichment of 7 per mille in the MTBE δ 13 C composition and an isotope enrichment factor (ε) of -1.53 per mille when dissolved O 2 was not limiting. However, for the low dissolved O 2 concentration of up to 2 mg/L that characterizes most of the MTBE plume fringe, aerobic MTBE biodegradation produced an enrichment of 0.5-0.7 per mille, corresponding to an ε value of -0.22 per mille to -0.24 per mille. No anaerobic MTBE biodegradation occurred under these experimental conditions. These results suggest the existence of a complex MTBE-biodegrading community in the aquifer, which may consist of different aerobic species competing for MTBE and dissolved O 2
Influence of gamma irradiation on phenolic compounds of minimally processed baby carrots

Energy Technology Data Exchange (ETDEWEB)

Hirashima, Fabiana K.; Fabbri, Adriana D.T.; Sagretti, Juliana M.A.; Nunes, Thaise C.F.; Sabato, Suzy F., E-mail: fmayumi@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Galvao, Natascha S.; Lanfer-Marquez, Ursula M., E-mail: lanferum@usp.br [Universidade de Sao Paulo (FCF/USP), SP (Brazil). Faculdade de Ciencias Farmaceuticas

2013-07-01

Consumption of fresh fruits and vegetables provide several health benefits including risk reduction of oxidative stress-related diseases. These benefits have been associated with bioactive compounds, mainly phenolic compounds. Minimally processed products are a growing segment in food retail establishments due its practicality and convenience without significantly altering fresh-like characteristics. To extend the shelf life of these products, an application of ionizing radiation is an alternative, based on a physical and non-thermal method of preservation. The effect of irradiation on phenolic compounds of minimally processed baby carrots have not been reported in literature yet. The aim of this study was to evaluate the levels of phenolic compounds in baby carrots after the irradiation process. Samples of minimally processed baby carrots were purchased at a local supermarket and irradiated with doses of 0.5 and 1.0 kGy. Phenolic compounds were extracted from shredded carrots with MeOH and analyzed spectrophotometrically by the Folin Ciocalteau method using a gallic acid standard curve. The results showed that the phenolic contents decreased significantly (p<0.05) with increasing radiation dose. In non-irradiated baby carrots (control), the levels of phenolic compounds were about 330 μg eq. gallic acid/g, while irradiated samples with 0.5 kGy, showed an approximately 10% reduction when compared with the control. An irradiation dose of 1.0 kGy caused a loss of 20%. Although the radiation has affected the phenolic content, the process seems to be interesting by maintaining their fresh-like characteristics. (author)
Influence of gamma irradiation on phenolic compounds of minimally processed baby carrots

International Nuclear Information System (INIS)

Hirashima, Fabiana K.; Fabbri, Adriana D.T.; Sagretti, Juliana M.A.; Nunes, Thaise C.F.; Sabato, Suzy F.; Galvao, Natascha S.; Lanfer-Marquez, Ursula M.

2013-01-01

Consumption of fresh fruits and vegetables provide several health benefits including risk reduction of oxidative stress-related diseases. These benefits have been associated with bioactive compounds, mainly phenolic compounds. Minimally processed products are a growing segment in food retail establishments due its practicality and convenience without significantly altering fresh-like characteristics. To extend the shelf life of these products, an application of ionizing radiation is an alternative, based on a physical and non-thermal method of preservation. The effect of irradiation on phenolic compounds of minimally processed baby carrots have not been reported in literature yet. The aim of this study was to evaluate the levels of phenolic compounds in baby carrots after the irradiation process. Samples of minimally processed baby carrots were purchased at a local supermarket and irradiated with doses of 0.5 and 1.0 kGy. Phenolic compounds were extracted from shredded carrots with MeOH and analyzed spectrophotometrically by the Folin Ciocalteau method using a gallic acid standard curve. The results showed that the phenolic contents decreased significantly (p<0.05) with increasing radiation dose. In non-irradiated baby carrots (control), the levels of phenolic compounds were about 330 μg eq. gallic acid/g, while irradiated samples with 0.5 kGy, showed an approximately 10% reduction when compared with the control. An irradiation dose of 1.0 kGy caused a loss of 20%. Although the radiation has affected the phenolic content, the process seems to be interesting by maintaining their fresh-like characteristics. (author)
Enhanced degradation of phenolic compounds in coal gasification wastewater by a novel integration of micro-electrolysis with biological reactor (MEBR) under the micro-oxygen condition.

Science.gov (United States)

Ma, Weiwei; Han, Yuxing; Xu, Chunyan; Han, Hongjun; Ma, Wencheng; Zhu, Hao; Li, Kun; Wang, Dexin

2018-03-01

The aim of this work was to study an integration of micro-electrolysis with biological reactor (MEBR) for strengthening removal of phenolic compounds in coal gasification wastewater (CGW). The results indicated MEBR achieved high efficiencies in removal of COD and phenolic compounds as well as improvement of biodegradability of CGW under the micro-oxygen condition. The integrated MEBR process was more favorable to improvement of the structural stability of activated sludge and biodiversity of specific functional microbial communities. Especially, Shewanella and Pseudomonas were enriched to accelerate the extracellular electron transfer, finally facilitating the degradation of phenolic compounds. Moreover, MEBR process effectively relieved passivation of Fe-C filler surface and prolonged lifespan of Fe-C filler. Accordingly, the synergetic effect between iron-carbon micro-electrolysis (ICME) and biological action played a significant role in performance of the integrated process. Therefore, the integrated MEBR was a promising practical process for enhancing CGW treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.
Editorial: Biodegradable Materials

Directory of Open Access Journals (Sweden)

Carl Schaschke

2014-11-01

Full Text Available This Special Issue “Biodegradable Materials” features research and review papers concerning recent advances on the development, synthesis, testing and characterisation of biomaterials. These biomaterials, derived from natural and renewable sources, offer a potential alternative to existing non-biodegradable materials with application to the food and biomedical industries amongst many others. In this Special Issue, the work is expanded to include the combined use of fillers that can enhance the properties of biomaterials prepared as films. The future application of these biomaterials could have an impact not only at the economic level, but also for the improvement of the environment.
Quantifying MTBE biodegradation in the Vandenberg Air Force Base ethanol release study using stable carbon isotopes

Science.gov (United States)

McKelvie, Jennifer R.; Mackay, Douglas M.; de Sieyes, Nicholas R.; Lacrampe-Couloume, Georges; Sherwood Lollar, Barbara

2007-12-01

Compound-specific isotope analysis (CSIA) was used to assess biodegradation of MTBE and TBA during an ethanol release study at Vandenberg Air Force Base. Two continuous side-by-side field releases were conducted within a preexisting MTBE plume to form two lanes. The first involved the continuous injection of site groundwater amended with benzene, toluene and o-xylene ("No ethanol lane"), while the other involved the continuous injection of site groundwater amended with benzene, toluene and o-xylene and ethanol ("With ethanol lane"). The δ 13C of MTBE for all wells in the "No ethanol lane" remained constant during the experiment with a mean value of - 31.3 ± 0.5‰ ( n = 40), suggesting the absence of any substantial MTBE biodegradation in this lane. In contrast, substantial enrichment in 13C of MTBE by 40.6‰, was measured in the "With ethanol lane", consistent with the effects of biodegradation. A substantial amount of TBA (up to 1200 μg/L) was produced by the biodegradation of MTBE in the "With ethanol lane". The mean value of δ 13C for TBA in groundwater samples in the "With ethanol lane" was - 26.0 ± 1.0‰ ( n = 32). Uniform δ 13C TBA values through space and time in this lane suggest that substantial anaerobic biodegradation of TBA did not occur during the experiment. Using the reported range in isotopic enrichment factors for MTBE of - 9.2‰ to - 15.6‰, and values of δ 13C of MTBE in groundwater samples, MTBE first-order biodegradation rates in the "With ethanol lane" were 12.0 to 20.3 year - 1 ( n = 18). The isotope-derived rate constants are in good agreement with the previously published rate constant of 16.8 year - 1 calculated using contaminant mass-discharge for the "With ethanol lane".
A phenomenological constitutive model for the nonlinear viscoelastic responses of biodegradable polymers

KAUST Repository

Khan, Kamran

2012-11-09

We formulate a constitutive framework for biodegradable polymers that accounts for nonlinear viscous behavior under regimes with large deformation. The generalized Maxwell model is used to represent the degraded viscoelastic response of a polymer. The large-deformation, time-dependent behavior of viscoelastic solids is described using an Ogden-type hyperviscoelastic model. A deformation-induced degradation mechanism is assumed in which a scalar field depicts the local state of the degradation, which is responsible for the changes in the material\\'s properties. The degradation process introduces another timescale (the intrinsic material clock) and an entropy production mechanism. Examples of the degradation of a polymer under various loading conditions, including creep, relaxation and cyclic loading, are presented. Results from parametric studies to determine the effects of various parameters on the process of degradation are reported. Finally, degradation of an annular cylinder subjected to pressure is also presented to mimic the effects of viscoelastic arterial walls (the outer cylinder) on the degradation response of a biodegradable stent (the inner cylinder). A general contact analysis is performed. As the stiffness of the biodegradable stent decreases, stress reduction in the stented viscoelastic arterial wall is observed. The integration of the proposed constitutive model with finite element software could help a designer to predict the time-dependent response of a biodegradable stent exhibiting finite deformation and under complex mechanical loading conditions. © 2012 Springer-Verlag Wien.
Using the properties of organic compounds to help design a treatment system

International Nuclear Information System (INIS)

Nyer, E.; Boettcher, G.; Morello, B.

1991-01-01

The author provides the physical/chemical and treatability properties of 50 organic compounds. The physical/chemical parameters of the compounds can be used to help evaluate data generated during remedial investigations. The treatability parameters can be used as a basis for the preliminary design of a treatment system that will remove organic compounds from ground water. The main physical/chemical properties that should be evaluated prior to design are solubility, specific gravity, and octanol/water coefficient. Based on this determination, the treatability is determined for carbon adsorption and biodegradability
Definition of a concrete bio-decontamination process in nuclear substructures; Biodegradation de matrices cimentaires en vue de leur decontamination

Energy Technology Data Exchange (ETDEWEB)

Jestin, A

2005-05-15

The decontamination of sub-structural materials represents a stake of high-importance because of the high volume generated. It is agreed then to propose efficient and effective processes. The process of bio-decontamination of the hydraulic binders leans on the mechanisms of biodegradation of concretes, phenomenon characterized in the 40's by an indirect attack of the material by acids stem from the microbial metabolism: sulphuric acid (produced by Thiobacillus), nitric acid (produced by Nitrosomonas and Nitrobacter) and organic acids (produced by fungi). The principle of the bio-decontamination process is to apply those micro-organisms on the surface of the contaminated material, in order to damage its surface and to retrieve the radionuclides. One of the multiple approaches of the process is the use of a bio-gel that makes possible the micro-organisms application. (author)
Biodegradation of starch–graft–polystyrene and starch–graft–poly(methacrylic acid copolymers in model river water

Directory of Open Access Journals (Sweden)

Nikolić Vladimir

2013-01-01

Full Text Available In this paper the biodegradation study of grafted copolymers of polystyrene (PS and corn starch and poly(methacrylic acid and corn starch in model river water is described. These copolymers were obtained in the presence of different amine activators. The synthesized copolymers and products of degradation were characterized by Fourier Transform Infrared Spectroscopy (FTIR and Scanning Electron Microscopy (SEM. Biodegradation was monitored by mass decrease and number of microorganisms by Koch’s method. Biodegradation of both copolymers advanced with time, poly(methacrylic acid-graft-starch copolymers completely degraded after 21 day, and polystyrene-graft-starch partially degraded (45.78-93.09 % of total mass after 27 days. Differences in the degree of biodegradation are consequences of different structure of the samples, and there is a significant negative correlation between the share of polystyrene in copolymer and degree of biodegradation. The grafting degree of PS necessary to prevent biodegradation was 54 %. Based on experimental evidence, mechanisms of both biodegradation processes are proposed, and influence of degree of starch and synthetic component of copolymers on degradation were established. [Projekat Ministarstva nauke Republike Srbije, br. 172001 i br. 172062
Study and optimization of the biodegradation of Polycyclic Aromatic Hydrocarbons (PAHs) and Poly-chloro-biphenyls (PCBs) during the anaerobic and aerobic digestion of long-term contaminated urban sludge; Etude et optimisation de la biodegradation d'hydrocarbures aromatiques polycycliques (HAPs) et de polychlorobiphenyls (PCBs) au cours de la digestion anaerobie et aerobie de boues urbaines contaminees

Energy Technology Data Exchange (ETDEWEB)

Trably, E.

2002-12-15

This study deals with the behavior of PAHs and PCBs during anaerobic and aerobic digestion of long-term contaminated sludge. Initially, an analytical method of 13 PAHs in sludge was developed to PAH-monitoring in laboratory-scaled bioreactors. For this, the method was optimized and validated for its high accuracy and its high reproducibility. In order to estimate precisely the PAH and PCB biological removal performances of each reactor, it was also proposed a method of analysis of the results based on mass balance. Therefore, it was observed for the first time significant PAHs removal under methanogenic conditions. It was also shown that PAH and PCB removals were limited by the mass transfer kinetics and particularly by the reduction of solids. The anaerobic and aerobic processes were then optimized by improving the PAH diffusion with the enhancement of reactor temperature and with the addition of surfactants and solvent, such as methanol. It was highlighted the great fragility of the methanogenic ecosystems and, on the opposite, the strong potential of the aerobic ecosystem for PAHs biodegradation. Indeed, some aerobic processes were successful in decontaminating sludge significantly (at 45 deg. C or in the presence of methanol). Lastly, the PAH biodegradation was characterized partly by the monitoring of {sup 14}C-radiolabelled compounds and by the molecular identification of the methanogenic archaea species. It was suggested that some archaea microorganisms were implied in PAHs biodegradation under strict anaerobic methanogenic conditions. (author)
Time Course-Dependent Methanogenic Crude Oil Biodegradation: Dynamics of Fumarate Addition Metabolites, Biodegradative Genes, and Microbial Community Composition

Directory of Open Access Journals (Sweden)

Courtney R. A. Toth

2018-01-01

Full Text Available Biodegradation of crude oil in subsurface petroleum reservoirs has adversely impacted most of the world's oil, converting this resource to heavier forms that are of lower quality and more challenging to recover. Oil degradation in deep reservoir environments has been attributed to methanogenesis over geological time, yet our understanding of the processes and organisms mediating oil transformation in the absence of electron acceptors remains incomplete. Here, we sought to identify hydrocarbon activation mechanisms and reservoir-associated microorganisms that may have helped shape the formation of biodegraded oil by incubating oilfield produced water in the presence of light (°API = 32 or heavy crude oil (°API = 16. Over the course of 17 months, we conducted routine analytical (GC, GC-MS and molecular (PCR/qPCR of assA and bssA genes, 16S rRNA gene sequencing surveys to assess microbial community composition and activity changes over time. Over the incubation period, we detected the formation of transient hydrocarbon metabolites indicative of alkane and alkylbenzene addition to fumarate, corresponding with increases in methane production and fumarate addition gene abundance. Chemical and gene-based evidence of hydrocarbon biodegradation under methanogenic conditions was supported by the enrichment of hydrocarbon fermenters known to catalyze fumarate addition reactions (e.g., Desulfotomaculum, Smithella, along with syntrophic bacteria (Syntrophus, methanogenic archaea, and several candidate phyla (e.g., “Atribacteria”, “Cloacimonetes”. Our results reveal that fumarate addition is a possible mechanism for catalyzing the methanogenic biodegradation of susceptible saturates and aromatic hydrocarbons in crude oil, and we propose the roles of community members and candidate phyla in our cultures that may be involved in hydrocarbon transformation to methane in crude oil systems.
Biodegradation Behaviour of Thermoplastic Starch Films Derived from Tacca leontopetaloides Starch under Controlled Composting Condition

Science.gov (United States)

Amin, A. M. Mohd; Sauid, S. Mohd; Hamid, K. H. Ku; Musa, M.

2018-05-01

The biodegradation study of thermoplastic starch (TPS) films derived from Tacca leontopetaloides starch; namely TPS/GLY, TPS/ACE and TPS/BCHR were investigated under controlled composting conditions. A manual set-up test rig in laboratory scale was built according to ISO 14855-1: 2012. The biodegradation percentage was determined by measuring the amount of CO2 evolved using titration method and validated by automatic system (Arduino UNO System) that detected the CO2 evolved. After 45 days under controlled composting condition, results indicated that TPS/GLY degraded the fastest, followed by TPS/BCHR and the TPS/ACE had the slowest degradation. The biodegradation process of TPS/GLY, TPS/ACE and TPS/BCHR also exhibited two stages with different degradation speeds. From these results, it indicated that chemical modification of the TPS films by adding acetic acid and rice husk bio-char to the thermoplastic starch can have a major impact on the biodegradation rate and final biodegradation percentage.
Food processing strategies to enhance phenolic compounds bioaccessibility and bioavailability in plant-based foods.

Science.gov (United States)

Ribas-Agustí, Albert; Martín-Belloso, Olga; Soliva-Fortuny, Robert; Elez-Martínez, Pedro

2017-06-13

Phenolic compounds are important constituents of plant-based foods, as their presence is related to protective effects on health. To exert their biological activity, phenolic compounds must be released from the matrix during digestion in an absorbable form (bioaccessible) and finally absorbed and transferred to the bloodstream (bioavailable). Chemical structure and matrix interactions are some food-related factors that hamper phenolic compounds bioaccessibility and bioavailability, and that can be counteracted by food processing. It has been shown that food processing can induce chemical or physical modifications in food that enhance phenolic compounds bioaccessibility and bioavailability. These changes include: (i) chemical modifications into more bioaccessible and bioavailable forms; (ii) cleavage of covalent or hydrogen bonds or hydrophobic forces that attach phenolic compounds to matrix macromolecules; (iii) damaging microstructural barriers such as cell walls that impede the release from the matrix; and (iv) create microstructures that protect phenolic compounds until they are absorbed. Indeed, food processing can produce degradation of phenolic compounds, however, it is possible to counteract it by modulating the operating conditions in favor of increased bioaccessibility and bioavailability. This review compiles the current knowledge on the effects of processing on phenolic compounds bioaccessibility or bioavailability, while suggesting new guidelines in the search of optimal processing conditions as a step forward towards the design of healthier foods.
Fate of pharmaceutical compounds in hydroponic mesocosms planted with Scirpus validus

International Nuclear Information System (INIS)

Zhang, Dong Qing; Gersberg, Richard M.; Hua, Tao; Zhu, Junfei; Goyal, Manish Kumar; Ng, Wun Jern; Tan, Soon Keat

2013-01-01

A systematic approach to assess the fate of selected pharmaceuticals (carbamazepine, naproxen, diclofenac, clofibric acid and caffeine) in hydroponic mesocosms is described. The overall objective was to determine the kinetics of depletion (from solution) and plant uptake for these compounds in mesocosms planted with S. validus growing hydroponically. The potential for translocation of these pharmaceuticals from the roots to the shoots was also assessed. After 21 days of incubation, nearly all of the caffeine, naproxen and diclofenac were eliminated from solution, whereas carbamazepine and clofibric acid were recalcitrant to both photodegradation and biodegradation. The fact that the BAFs for roots for carbamazepine and clofibric acid were greater than 5, while the BAFs for naproxen, diclofenac and caffeine were less than 5, implied that the latter two compounds although recalcitrant to biodegradation, still had relatively high potential for plant uptake. Naproxen was sensitive to both photodegradation (30–42%) and biodegradation (>50%), while diclofenac was particularly sensitive (>70%) to photodegradation alone. No significant correlations (p > 0.05) were found between the rate constants of depletion or plant tissue levels of the pharmaceuticals and either log K ow or log D ow . -- Highlights: •All of pharmaceuticals were removed from solution efficiently after 21 d of incubation. •Effects of photodegradation and biodegradation on pharmaceutical removal were studied. •The pharmaceutical concentrations in the plant tissues were detected. •No correlation was found between pharmaceutical levels in plant tissues and log K ow or log D ow . •Log K ow is the most significant parameter for predicting pharmaceutical levels. -- All the tested pharmaceuticals (carbamazepine, naproxen, diclofenac, clofibric acid and caffeine) were efficiently removed from nutrient solution
Biodegradability and aging study of rubber films obtained by gamma radiation vulcanization processes of latex

International Nuclear Information System (INIS)

Martins, Carlos Felipe Pinto

2005-01-01

The natural rubber latex (NRL) is industrially crosslinked by the conventional process of vulcanization, which uses sulphur and heat. Otherwise, the network can also be done by the alternative process with ionizing radiation. In this work the crosslinking of NRL was studied by the comparison of the conventional vulcanization system and the ionizing radiation process of 60 C source. The products obtained, the irradiated latex, the irradiated latex with approximately 1% of soy lecithin and the sulphur vulcanized latex were tested by accelerated aging with ultraviolet (UV) and outdoor aging with compostage, tensile strength at break, swelling and gel fraction, fungi micro biota, scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and thermogravimetry and differential scanning calorimetry analysis (TG and DSC). The results showed that the aging with microorganisms have a great influence in the physical properties of the samples. The thermal stability order observed showed that the sulphur vulcanized latex is more resistant, what is probably associated to a network more stable under the aging conditions. On the other hand, the irradiated latex showed intense biodegradation aspects, particularly with the presence of the soy lecithin. (author)
Anaerobic biodegradability and treatment of Egyption domestic sewage

NARCIS (Netherlands)

Elmitwally, T.A.; Al-Sarawey, A.; El-Sherbiny, M.F.; Zeeman, G.; Lettinga, G.

2003-01-01

The anaerobic biodegradability of domestic sewage for four Egyptian villages and four Egyptian cities was determined in batch experiments. The results showed that the biodegradability of the Egyptian-villages sewage (73%) was higher than that of the cities (66%). The higher biodegradability of the

Biodegradation of photo-oxidized lignite and characterization of the products

Science.gov (United States)

Li, Jiantao; Liu, Xiangrong; Yue, Zilin; Zhang, Yaowen

2018-01-01

Biodegradation of photo-oxidized Inner Mongolia lignite by pseudomonas aeruginosa was studied and the degradation percentage reached 56.27%, while the corresponding degradation percentage of the strain degrading raw Inner Mongolia lignite is only 23.16%. The degradation products were characterized. Proximate and ultimate analyses show that the higher oxygen content increased by photo-oxidation pretreatment maybe promoted the degradation process. Ultraviolet spectroscopy (UV) analysis of the liquid product reveals that it contains unsaturated structures and aromatic rings are the main structure units. Gas chromatography-mass spectrometry (GC-MS) analysis indicates that the main components of the ethyl acetate extracts are low molecular weight organic compounds, such as ketones, acids, hydrocarbons, esters and alcohols. Infrared spectroscopy (IR) analysis of raw lignite, photo-oxidized lignite and residual lignite demonstrates that the absorption peaks of functional groups in residual lignite disappeared or weakened obviously. Scanning electron microscopy (SEM) analysis manifests that small holes appear in photo-oxidized lignite surface, which may be promote the degradation process and this is only from the physical morphology aspects, so it can be inferred from the tests and analyses results that the more important reason of the high degradation percentage is mostly that the photo-oxidation pretreatment changes the chemical structures of lignite.
Biodegradable films and spray coatings as eco-friendly alternative to petro-chemical derived mulching films

Directory of Open Access Journals (Sweden)

G. Vox

2013-09-01

Full Text Available The use of plastic mulching films in horticulture causes the serious drawback of huge amount of wastes to be disposed of at the end of their lifetime. Several pre-competitive research products based on raw materials coming from renewable sources were recently developed to be used as biodegradable materials for soil mulching. Biodegradable materials are designed in order both to retain their mechanical and physical properties during their using time and to degrade at the end of their lifetime. These materials can be integrated directly in the soil in order to biodegrade because the bacterial flora transforms them in carbon dioxide or methane, water and biomass. The innovative materials can be obtained using natural polymers, such as starch, cellulose, chitosan, alginate and glucomannan. Biodegradable extruded mulching films were performed by means of thermo-plasticizing process. Spray mulch coatings were realized directly in field, by spraying water solutions based on natural polysaccharides, thus covering the cultivated soil with a protective thin geo-membrane. In this paper an overview on the formulation development, processing understanding, field performance, mechanical and radiometric properties of these innovative materials for soil mulching is presented. In field the biodegradable mulching films showed suitable mechanical properties if compared to the low density polyethylene films. The radiometric properties and their effect on the temperature condition and on weed control in the mulched soil were evaluated too. At the end of their lifetime the biodegradable materials were shattered and buried into the soil together with plants.
Biodegradable Metals From Concept to Applications

CERN Document Server

Hermawan, Hendra

2012-01-01

This book in the emerging research field of biomaterials covers biodegradable metals for biomedical applications. The book contains two main parts where each of them consists of three chapters. The first part introduces the readers to the field of metallic biomaterials, exposes the state of the art of biodegradable metals, and reveals its application for cardiovascular implants. It includes some fundamental aspects to give basic understanding on metals for further review on the degradable ones is covered in chapter one. The second chapter introduces the concept of biodegradable metals, it's st
BIODEGRADATION OF SUGARCANE VINASSES BY THE WHITE-ROT FUNGI Pleurotus ostreatus IN A PACKED BED REACTOR

Directory of Open Access Journals (Sweden)

W.A. Tapie

2016-08-01

Full Text Available Sugarcane vinasses are considered a complex effluent because of its organic load, low pH, high temperature, and by the presence of recalcitrant substances such as melanoidins and phenolic compounds. The aim of this work was to evaluate the potential of the fungus Pleurotus ostreatus to carry out the biodegradation of sugarcane vinasses in a fixed-bed bioreactor. The experiments evidence the potential of the fungus Pleurotus ostreatus to carry out the decolorization (83%, the removal of the Chemical Oxygen Demand (COD=87% and the Biochemical Oxygen Demand (BOD5=92%, the reduction of total suspended solids (83% and volatile suspended solids (72% of vinasses. The technical simplicity of the proposed alternative as well as process performance reveals the potential of the fungus Pleurotus ostreatus for the treatment of sugarcane mill effluents.
Biodegradation of acetanilide herbicides acetochlor and butachlor in soil.

Science.gov (United States)

Ye, Chang-ming; Wang, Xing-jun; Zheng, He-hui

2002-10-01

The biodegradation of two acetanilide herbicides, acetochlor and butachlor in soil after other environmental organic matter addition were measured during 35 days laboratory incubations. The herbicides were applied to soil alone, soil-SDBS (sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid) mixtures. Herbicide biodegradation kinetics were compared in the different treatment. Biodegradation products of herbicides in soil alone samples were identified by GC/MS at the end of incubation. Addition of SDBS and HA to soil decreased acetochlor biodegradation, but increased butachlor biodegradation. The biodegradation half-life of acetochlor and butachlor in soil alone, soil-SDBS mixtures and soil-HA mixtures were 4.6 d, 6.1 d and 5.4 d and 5.3 d, 4.9 d and 5.3 d respectively. The biodegradation products were hydroxyacetochlor and 2-methyl-6-ethylaniline for acetochlor, and hydroxybutachlor and 2,6-diethylaniline for butachlor.
The electrochemical reduction processes of solid compounds in high temperature molten salts.

Science.gov (United States)

Xiao, Wei; Wang, Dihua

2014-05-21

Solid electrode processes fall in the central focus of electrochemistry due to their broad-based applications in electrochemical energy storage/conversion devices, sensors and electrochemical preparation. The electrolytic production of metals, alloys, semiconductors and oxides via the electrochemical reduction of solid compounds (especially solid oxides) in high temperature molten salts has been well demonstrated to be an effective and environmentally friendly process for refractory metal extraction, functional materials preparation as well as spent fuel reprocessing. The (electro)chemical reduction of solid compounds under cathodic polarizations generally accompanies a variety of changes at the cathode/melt electrochemical interface which result in diverse electrolytic products with different compositions, morphologies and microstructures. This report summarizes various (electro)chemical reactions taking place at the compound cathode/melt interface during the electrochemical reduction of solid compounds in molten salts, which mainly include: (1) the direct electro-deoxidation of solid oxides; (2) the deposition of the active metal together with the electrochemical reduction of solid oxides; (3) the electro-inclusion of cations from molten salts; (4) the dissolution-electrodeposition process, and (5) the electron hopping process and carbon deposition with the utilization of carbon-based anodes. The implications of the forenamed cathodic reactions on the energy efficiency, chemical compositions and microstructures of the electrolytic products are also discussed. We hope that a comprehensive understanding of the cathodic processes during the electrochemical reduction of solid compounds in molten salts could form a basis for developing a clean, energy efficient and affordable production process for advanced/engineering materials.
Mathematical modeling of the effects of aerobic and anaerobic chelate biodegradation on actinide speciation

International Nuclear Information System (INIS)

Banaszak, J.E.; VanBriesen, J.; Rittmann, B.E.; Reed, D.T.

1998-01-01

Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and, hence, the mobility of actinides in subsurface environments. We combined mathematical modeling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bio-utilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modeling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems
Mathematical modelling of the effects of aerobic and anaerobic chelate biodegradation on actinide speciation

International Nuclear Information System (INIS)

Banaszak, J.E.; VanBriesen, J.M.; Rittmann, B.E.; Reed, D.T.

1998-01-01

Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and hence, the mobility of actinides in subsurface environments. We combined mathematical modelling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bioutilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modelling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems. (orig.)
Microbial transformations of natural organic compounds and radionuclides in subsurface environments

International Nuclear Information System (INIS)

Francis, A.J.

1985-10-01

A major national concern in the subsurface disposal of energy wastes is the contamination of ground and surface waters by waste leachates containing radionuclides, toxic metals, and organic compounds. Microorganisms play an important role in the transformation of organic compounds, radionuclides, and toxic metals present in the waste and affect their mobility in subsurface environments. Microbial processes involved in dissolution, mobilization, and immobilization of toxic metals under aerobic and anaerobic conditions are briefly reviewed. Metal complexing agents and several organic acids produced by microbial action affect mobilization of radionuclides and toxic metals in subsurface environments. Information on the persistence of and biodegradation rates of synthetic as well as microbiologically produced complexing agents is scarce but important in determining the mobility of metal organic complexes in subsoils. Several gaps in knowledge in the area of microbial transformation of naturally occurring organics, radionuclides, and toxic metals have been identified, and further basic research has been suggested. 31 refs., 1 fig., 3 tabs
Abiotic and biotic degradation of oxo-biodegradable plastic bags by Pleurotus ostreatus.

Directory of Open Access Journals (Sweden)

José Maria Rodrigues da Luz

Full Text Available In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2 concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.
Abiotic and biotic degradation of oxo-biodegradable plastic bags by Pleurotus ostreatus.

Science.gov (United States)

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina Megumi

2014-01-01

In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.
Abiotic and Biotic Degradation of Oxo-Biodegradable Plastic Bags by Pleurotus ostreatus

Science.gov (United States)

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Bazzolli, Denise Mara Soares; Tótola, Marcos Rogério; Demuner, Antônio Jacinto; Kasuya, Maria Catarina Megumi

2014-01-01

In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO2) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process. PMID:25419675
Evaluation of the persistence of transformation products from ozonation of trace organic compounds - a critical review.

Science.gov (United States)

Hübner, Uwe; von Gunten, Urs; Jekel, Martin

2015-01-01

Ozonation is an efficient treatment system to reduce the concentration of trace organic compounds (TrOCs) from technical aquatic systems such as drinking water, wastewater and industrial water, etc. Although it is well established that ozonation generally improves the removal of organic matter in biological post-treatment, little is known about the biodegradability of individual transformation products resulting from ozonation of TrOCs. This publication provides a qualified assessment of the persistence of ozone-induced transformation products based on a review of published product studies and an evaluation of the biodegradability of transformation products with the biodegradability probability program (BIOWIN) and the University of Minnesota Pathway Prediction System (UM-PPS). The oxidation of TrOCs containing the four major ozone-reactive sites (olefins, amines, aromatics and sulfur-containing compounds) follows well described reaction pathways leading to characteristic transformation products. Assessment of biodegradability revealed a high sensitivity to the formed products and hence the ozone-reactive site present in the target compound. Based on BIOWIN, efficient removal can be expected for products from cleavage of olefin groups and aromatic rings. In contrast, estimations and literature indicate that hydroxylamines and N-oxides, the major products from ozonation of secondary and tertiary amines are not necessarily better removed in biological post-treatment. According to UM-PPS, degradation of these products might even occur via reformation of the corresponding amine. Some product studies with sulfide-containing TrOCs showed a stoichiometric formation of sulfoxides from oxygen transfer reactions. However, conclusions on the fate of transformation products in biological post-treatment cannot be drawn based on BIOWIN and UM-PPS.
The influence of nonionic surfactant Brij 30 on biodegradation of ...

African Journals Online (AJOL)

ONOS

2010-09-06

Sep 6, 2010 ... polluted air stream using biological process is highly efficient and has low ... Brij 30 was the most biodegradable surfactant among Brij 30, Tween 80 and ... The filter material contained surfactants that would enhance the ...
Mathematical modelling of oil spill fate and transport in the marine environment incorporating biodegradation kinetics of oil droplets

Science.gov (United States)

Spanoudaki, Katerina

2016-04-01

Oil biodegradation by native bacteria is one of the most important natural processes that can attenuate the environmental impacts of marine oil spills. However, very few numerical models of oil spill fate and transport include biodegradation kinetics of spilled oil. Furthermore, in models where biodegradation is included amongst the oil transformation processes simulated, it is mostly represented as a first order decay process neglecting the effect of several important parameters that can limit biodegradation rate, such as oil composition and oil droplets-water interface. To this end, the open source numerical model MEDSKIL-II, which simulates oil spill fate and transport in the marine environment, has been modified to include biodegradation kinetics of oil droplets dispersed in the water column. MEDSLIK-II predicts the transport and weathering of oil spills following a Lagrangian approach for the solution of the advection-diffusion equation. Transport is governed by the 3D sea currents and wave field provided by ocean circulation models. In addition to advective and diffusive displacements, the model simulates several physical and chemical processes that transform the oil (evaporation, emulsification, dispersion in the water column, adhesion to coast). The fate algorithms employed in MEDSLIK-II consider the oil as a uniform substance whose properties change as the slick weathers, an approach that can lead to reduced accuracy, especially in the estimation of oil evaporation and biodegradation. Therefore MEDSLIK-II has been modified by adopting the "pseudo-component" approach for simulating weathering processes. Spilled oil is modelled as a relatively small number of discrete, non-interacting components (pseudo-components). Chemicals in the oil mixture are grouped by physical-chemical properties and the resulting pseudo-component behaves as if it were a single substance with characteristics typical of the chemical group. The fate (evaporation, dispersion
Rapid prototyping of biodegradable microneedle arrays by integrating CO2 laser processing and polymer molding

International Nuclear Information System (INIS)

Tu, K T; Chung, C K

2016-01-01

An integrated technology of CO 2 laser processing and polymer molding has been demonstrated for the rapid prototyping of biodegradable poly-lactic-co-glycolic acid (PLGA) microneedle arrays. Rapid and low-cost CO 2 laser processing was used for the fabrication of a high-aspect-ratio microneedle master mold instead of conventional time-consuming and expensive photolithography and etching processes. It is crucial to use flexible polydimethylsiloxane (PDMS) to detach PLGA. However, the direct CO 2 laser-ablated PDMS could generate poor surfaces with bulges, scorches, re-solidification and shrinkage. Here, we have combined the polymethyl methacrylate (PMMA) ablation and two-step PDMS casting process to form a PDMS female microneedle mold to eliminate the problem of direct ablation. A self-assembled monolayer polyethylene glycol was coated to prevent stiction between the two PDMS layers during the peeling-off step in the PDMS-to-PDMS replication. Then the PLGA microneedle array was successfully released by bending the second-cast PDMS mold with flexibility and hydrophobic property. The depth of the polymer microneedles can range from hundreds of micrometers to millimeters. It is linked to the PMMA pattern profile and can be adjusted by CO 2 laser power and scanning speed. The proposed integration process is maskless, simple and low-cost for rapid prototyping with a reusable mold. (paper)
Rapid prototyping of biodegradable microneedle arrays by integrating CO2 laser processing and polymer molding

Science.gov (United States)

Tu, K. T.; Chung, C. K.

2016-06-01

An integrated technology of CO2 laser processing and polymer molding has been demonstrated for the rapid prototyping of biodegradable poly-lactic-co-glycolic acid (PLGA) microneedle arrays. Rapid and low-cost CO2 laser processing was used for the fabrication of a high-aspect-ratio microneedle master mold instead of conventional time-consuming and expensive photolithography and etching processes. It is crucial to use flexible polydimethylsiloxane (PDMS) to detach PLGA. However, the direct CO2 laser-ablated PDMS could generate poor surfaces with bulges, scorches, re-solidification and shrinkage. Here, we have combined the polymethyl methacrylate (PMMA) ablation and two-step PDMS casting process to form a PDMS female microneedle mold to eliminate the problem of direct ablation. A self-assembled monolayer polyethylene glycol was coated to prevent stiction between the two PDMS layers during the peeling-off step in the PDMS-to-PDMS replication. Then the PLGA microneedle array was successfully released by bending the second-cast PDMS mold with flexibility and hydrophobic property. The depth of the polymer microneedles can range from hundreds of micrometers to millimeters. It is linked to the PMMA pattern profile and can be adjusted by CO2 laser power and scanning speed. The proposed integration process is maskless, simple and low-cost for rapid prototyping with a reusable mold.
Iron-Dependent Enzyme Catalyzes the Initial Step in Biodegradation of N-Nitroglycine by Variovorax sp. Strain JS1663.

Science.gov (United States)

Mahan, Kristina M; Zheng, Hangping; Fida, Tekle T; Parry, Ronald J; Graham, David E; Spain, Jim C

2017-08-01

Nitramines are key constituents of most of the explosives currently in use and consequently contaminate soil and groundwater at many military facilities around the world. Toxicity from nitramine contamination poses a health risk to plants and animals. Thus, understanding how nitramines are biodegraded is critical to environmental remediation. The biodegradation of synthetic nitramine compounds such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has been studied for decades, but little is known about the catabolism of naturally produced nitramine compounds. In this study, we report the isolation of a soil bacterium, Variovorax sp. strain JS1663, that degrades N -nitroglycine (NNG), a naturally produced nitramine, and the key enzyme involved in its catabolism. Variovorax sp. JS1663 is a Gram-negative, non-spore-forming motile bacterium isolated from activated sludge based on its ability to use NNG as a sole growth substrate under aerobic conditions. A single gene ( nnlA ) encodes an iron-dependent enzyme that releases nitrite from NNG through a proposed β-elimination reaction. Bioinformatics analysis of the amino acid sequence of NNG lyase identified a PAS (Per-Arnt-Sim) domain. PAS domains can be associated with heme cofactors and function as signal sensors in signaling proteins. This is the first instance of a PAS domain present in a denitration enzyme. The NNG biodegradation pathway should provide the basis for the identification of other enzymes that cleave the N-N bond and facilitate the development of enzymes to cleave similar bonds in RDX, nitroguanidine, and other nitramine explosives. IMPORTANCE The production of antibiotics and other allelopathic chemicals is a major aspect of chemical ecology. The biodegradation of such chemicals can play an important ecological role in mitigating or eliminating the effects of such compounds. N -Nitroglycine (NNG) is produced by the Gram-positive filamentous soil bacterium Streptomyces noursei This study reports the
Biodegradation of Cosmetics Products: A Computational Study of Cytochrome P450 Metabolism of Phthalates

Directory of Open Access Journals (Sweden)

Fabián G. Cantú Reinhard

2017-11-01

Full Text Available Cytochrome P450s are a broad class of enzymes in the human body with important functions for human health, which include the metabolism and detoxification of compounds in the liver. Thus, in their catalytic cycle, the P450s form a high-valent iron(IV-oxo heme cation radical as the active species (called Compound I that reacts with substrates through oxygen atom transfer. This work discusses the possible degradation mechanisms of phthalates by cytochrome P450s in the liver, through computational modelling, using 2-ethylhexyl-phthalate as a model substrate. Phthalates are a type of compound commonly found in the environment from cosmetics usage, but their biodegradation in the liver may lead to toxic metabolites. Experimental studies revealed a multitude of products and varying product distributions among P450 isozymes. To understand the regio- and chemoselectivity of phthalate activation by P450 isozymes, we focus here on the mechanisms of phthalate activation by Compound I leading to O-dealkylation, aliphatic hydroxylation and aromatic hydroxylation processes. We set up model complexes of Compound I with the substrate and investigated the reaction mechanisms for products using the density functional theory on models and did a molecular mechanics study on enzymatic structures. The work shows that several reaction barriers in the gas-phase are close in energy, leading to a mixture of products. However, when we tried to dock the substrate into a P450 isozyme, some of the channels were inaccessible due to unfavorable substrate positions. Product distributions are discussed under various reaction conditions and rationalized with valence bond and thermodynamic models.
Treating contaminated organic compounds using the DETOX process

International Nuclear Information System (INIS)

Elsberry, K.; Dhooge, P.M.

1993-01-01

Waste matrices containing organic compounds, radionuclides, and metals pose difficult problems in waste treatment and disposal when the organic compounds and/or metals are considered to be hazardous. This paper describes the results of bench-scale studies of DETOX applied to the components of liquid mixed wastes, with the goal of establishing parameters for designing a prototype waste treatment unit. Apparent reaction rate orders for organic compounds and the dependence of apparent reaction rate on solution composition and the contact area were measured for vacuum pump oil, scintillation fluids, and trichloroethylene. Reaction rate was superior in chloride-based solutions and was proportional to the contact area above about 20 g/kg loading of organic material. Oxidations in 4-L volume, mixed bench-top reactor have given destruction efficiencies of 0.999999+ g/g for common organic compounds. Reaction rates achieved in the mixed bench-top reactor were one to two orders of magnitude greater than had been achieved in unmixed reactions; a thoroughly mixed reactor should be capable of oxidizing 10 to 100+ g of organic material per L-hr. Results are also presented on the solvation efficiency of DETOX for mercury, cerium, and neodymium, and for removal/destruction of organic compounds sorbed on vermiculite. The next stage of development will be converting the bench-top unit to continuous processing

Nonparametric Bayesian inference for multidimensional compound Poisson processes

NARCIS (Netherlands)

Gugushvili, S.; van der Meulen, F.; Spreij, P.

2015-01-01

Given a sample from a discretely observed multidimensional compound Poisson process, we study the problem of nonparametric estimation of its jump size density r0 and intensity λ0. We take a nonparametric Bayesian approach to the problem and determine posterior contraction rates in this context,
Precipitate hydrolysis process for the removal of organic compounds from nuclear waste slurries

Science.gov (United States)

Doherty, J.P.; Marek, J.C.

1987-02-25

A process for removing organic compounds from a nuclear waste slurry comprising reacting a mixture of radioactive waste precipitate slurry and an acid in the presence of a catalytically effective amount of a copper(II) catalyst whereby the organic compounds in the precipitate slurry are hydrolyzed to form volatile organic compounds which are separated from the reacting mixture. The resulting waste slurry, containing less than 10 percent of the original organic compounds, is subsequently blended with high level radioactive sludge land transferred to a vitrification facility for processing into borosilicate glass for long-term storage. 2 figs., 3 tabs.
Biodegradable lubricants - ''the solution for future?''

International Nuclear Information System (INIS)

Jahan, A.

1997-01-01

The environmental impact of lubricants use concern the direct effects from spills but also the indirect effects such as their lifetime and the emissions from thermal engines. The biodegradable performances and the toxicity are the environmental criteria that must be taken into account in the development and application of lubricants together with their technical performances. This paper recalls first the definition of biodegradable properties of hydrocarbons and the standardized tests, in particular the CEC and AFNOR tests. Then, the biodegradable performances of basic oils (mineral, vegetal, synthetic esters, synthetic hydrocarbons etc..), finite lubricants (hydraulic fluids..) and engine oils is analyzed according to these tests. Finally, the definition of future standards would take into account all the environmental characteristics of the lubricant: biodegradable performances, energy balance (CO 2 , NOx and Hx emissions and fuel savings), eco-toxicity and technical performances (wearing and cleanliness). (J.S.)
Plant-associated bacterial degradation of toxic organic compounds in soil.

LENUS (Irish Health Repository)

McGuinness, Martina

2009-08-01

A number of toxic synthetic organic compounds can contaminate environmental soil through either local (e.g., industrial) or diffuse (e.g., agricultural) contamination. Increased levels of these toxic organic compounds in the environment have been associated with human health risks including cancer. Plant-associated bacteria, such as endophytic bacteria (non-pathogenic bacteria that occur naturally in plants) and rhizospheric bacteria (bacteria that live on and near the roots of plants), have been shown to contribute to biodegradation of toxic organic compounds in contaminated soil and could have potential for improving phytoremediation. Endophytic and rhizospheric bacterial degradation of toxic organic compounds (either naturally occurring or genetically enhanced) in contaminated soil in the environment could have positive implications for human health worldwide and is the subject of this review.
Biodegradation behaviors of cellulose nanocrystals -PVA nanocomposites

Directory of Open Access Journals (Sweden)

Mahdi Rohani

2014-11-01

Full Text Available In this research, biodegradation behaviors of cellulose nanocrystals-poly vinyl alcohol nanocomposites were investigated. Nanocomposite films with different filler loading levels (3, 6, 9 and 12% by wt were developed by solvent casting method. The effect of cellulose nanocrystals on the biodegradation behaviors of nanocomposite films was studied. Water absorption and water solubility tests were performed by immersing specimens into distilled water. The characteristic parameter of diffusion coefficient and maximum moisture content were determined from the obtained water absorption curves. The water absorption behavior of the nanocomposites was found to follow a Fickian behavior. The maximum water absorption and diffusion coefficients were decreased by increasing the cellulose nanocrystals contents, however the water solubility decrease. The biodegradability of the films was investigated by immersing specimens into cellulase enzymatic solution as well as by burial in soil. The results showed that adding cellulose nanocrystals increase the weight loss of specimens in enzymatic solution but decrease it in soil media. The limited biodegradability of specimens in soil media attributed to development of strong interactions with solid substrates that inhibit the accessibility of functional groups. Specimens with the low degree of hydrolysis underwent extensive biodegradation in both enzymatic and soil media, whilst specimens with the high degree of hydrolysis showed recalcitrance to biodegradation under those conditions.
Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

Science.gov (United States)

Aras, Neny Rasnyanti M.; Arcana, I. Made

2015-09-01

An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm-1 which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese stearate
Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

Energy Technology Data Exchange (ETDEWEB)

Aras, Neny Rasnyanti M., E-mail: neny.rasnyanti@gmail.com; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132 (Indonesia)

2015-09-30

An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm{sup −1} which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese
Synthesis of manganese stearate for high density polyethylene (HDPE) and its biodegradation

International Nuclear Information System (INIS)

Aras, Neny Rasnyanti M.; Arcana, I Made

2015-01-01

An oxidant additive is one type of additive used for oxo-biodegradable polymers. This additive was prepared by reaction multivalent transition metals and fatty acids to accelerate the degradation process of polymers by providing a thermal treatment or irradiation with light. This study focused on the synthesis of manganese stearate as an additive for application in High Density Polyethylene (HDPE), and the influence of manganese stearate on the characteristics of HDPE including their biodegradability. Manganese stearate was synthesized by the reaction of stearic acid with sodium hydroxide, and sodium stearate formed was reacted with manganese chloride tetrahydrate to form manganese stearate with a melting point of 100-110 °C. Based on the FTIR spectrum showed absorption peak at wave number around 1560 cm −1 which is an asymmetric vibration of CO functional group that binds to the manganese. The films of oxo-biodegradable polymer were prepared by blending HDPE and manganese stearate additives at various concentrations with using the polymer melting method, followed heating at a temperature of 50°C and 70°C for 10 days. The characterizations of the oxo-biodegradable polymers were carried out by analysis the functional groups (FTIR and ATR),thermal properties (TGA), surface properties (SEM), as well as analysis of the biodegradability (the biodegradation test by using activated sludge, % weight loss). Based on COi indicate that the additive of manganese stearate is active in oxidizing polymer by heating treatment. Results of biodegradation by microorganisms from activated sludge showed that the percentage weight loss of polymers increase with the increasing incubation time and the concentration of manganese stearate in HDPE. Biodegradability of HDPE with the addition of manganese stearate and followed by heating at a higher temperature was better observed. The highest percentage weight loss was obtained at the polymer with concentration of 0.2% manganese
Use of Silica-Encapsulated Pseudomonas sp. Strain NCIB 9816-4 in Biodegradation of Novel Hydrocarbon Ring Structures Found in Hydraulic Fracturing Waters

Science.gov (United States)

Aukema, Kelly G.; Kasinkas, Lisa; Aksan, Alptekin

2014-01-01

The most problematic hydrocarbons in hydraulic fracturing (fracking) wastewaters consist of fused, isolated, bridged, and spiro ring systems, and ring systems have been poorly studied with respect to biodegradation, prompting the testing here of six major ring structural subclasses using a well-characterized bacterium and a silica encapsulation system previously shown to enhance biodegradation. The direct biological oxygenation of spiro ring compounds was demonstrated here. These and other hydrocarbon ring compounds have previously been shown to be present in flow-back waters and waters produced from hydraulic fracturing operations. Pseudomonas sp. strain NCIB 9816-4, containing naphthalene dioxygenase, was selected for its broad substrate specificity, and it was demonstrated here to oxidize fundamental ring structures that are common in shale-derived waters but not previously investigated with this or related enzymes. Pseudomonas sp. NCIB 9816-4 was tested here in the presence of a silica encasement, a protocol that has previously been shown to protect bacteria against the extremes of salinity present in fracking wastewaters. These studies demonstrate the degradation of highly hydrophobic compounds by a silica-encapsulated model bacterium, demonstrate what it may not degrade, and contribute to knowledge of the full range of hydrocarbon ring compounds that can be oxidized using Pseudomonas sp. NCIB 9816-4. PMID:24907321
Radiation processing of biodegradable polymer hydrogel from cellulose derivatives

International Nuclear Information System (INIS)

Wach, Radoslaw A.; Mitomo, Hiroshi; Yoshii, Fumio; Kume, Tamikazu

2001-01-01

The effects of high-energy radiation on ethers of cellulose: carboxymethyl-, hydroxypropyl- and hydroxyethylcellulose have been investigated. Polymers were irradiated in solid state and aqueous solution at various concentrations. Degree of substitution (DS), the concentration in the solution and irradiation conditions had a significant impact on the obtained products. Irradiation of polymers in solid and in diluted solution resulted in their degradation. A novel hydrogels of such natural polymers were synthesized, without using any additives, by irradiation at high concentration. It was found that high DS of CMC promoted crosslinking and, for all of the ethers, the gel formation occurred easier for more concentrated solutions. Paste-like form of the initial material, when water plasticised the bulk of polymer mass, along with the high dose rate and preventing oxygen accessibility to the sample during irradiation were favorable for hydrogel preparation. Up to 95% of gel fraction was obtained from 50 and 60% CMC solutions irradiated by gamma rays or by a beam of accelerated electrons (EB). The other polymers were more sensitive to the dose rate and formed gels with higher gel fraction while processed by EB. Moreover, polymers (except CMC) treated by gamma rays were susceptible to degradation after application of a dose over 50-100 kGy. The presence of oxygen in the system during irradiation limited a gel content and was prone to easier degradation of already formed gel. Produced hydrogels swelled markedly by absorption when paced in the solvent. Crosslinked polymers showed susceptibility to degradation by cellulase enzyme and by the action of microorganisms in compost or under natural conditions in soil thus could be included into the group of biodegradable materials. (author)
Radiation processing of biodegradable polymer hydrogel from cellulose derivatives

Energy Technology Data Exchange (ETDEWEB)

Wach, Radoslaw A.; Mitomo, Hiroshi [Gunma Univ., Faculty of Engineering, Department of Biological and Chemical Engineering, Kiryu, Gunma (Japan); Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

2001-03-01

The effects of high-energy radiation on ethers of cellulose: carboxymethyl-, hydroxypropyl- and hydroxyethylcellulose have been investigated. Polymers were irradiated in solid state and aqueous solution at various concentrations. Degree of substitution (DS), the concentration in the solution and irradiation conditions had a significant impact on the obtained products. Irradiation of polymers in solid and in diluted solution resulted in their degradation. A novel hydrogels of such natural polymers were synthesized, without using any additives, by irradiation at high concentration. It was found that high DS of CMC promoted crosslinking and, for all of the ethers, the gel formation occurred easier for more concentrated solutions. Paste-like form of the initial material, when water plasticised the bulk of polymer mass, along with the high dose rate and preventing oxygen accessibility to the sample during irradiation were favorable for hydrogel preparation. Up to 95% of gel fraction was obtained from 50 and 60% CMC solutions irradiated by gamma rays or by a beam of accelerated electrons (EB). The other polymers were more sensitive to the dose rate and formed gels with higher gel fraction while processed by EB. Moreover, polymers (except CMC) treated by gamma rays were susceptible to degradation after application of a dose over 50-100 kGy. The presence of oxygen in the system during irradiation limited a gel content and was prone to easier degradation of already formed gel. Produced hydrogels swelled markedly by absorption when paced in the solvent. Crosslinked polymers showed susceptibility to degradation by cellulase enzyme and by the action of microorganisms in compost or under natural conditions in soil thus could be included into the group of biodegradable materials. (author)
Chiral Analysis of Pesticides and Drugs of Environmental Concern: Biodegradation and Enantiomeric Fraction

Directory of Open Access Journals (Sweden)

Alexandra S. Maia

2017-09-01

Full Text Available The importance of stereochemistry for medicinal chemistry and pharmacology is well recognized and the dissimilar behavior of enantiomers is fully documented. Regarding the environment, the significance is equivalent since enantiomers of chiral organic pollutants can also differ in biodegradation processes and fate, as well as in ecotoxicity. This review comprises designed biodegradation studies of several chiral drugs and pesticides followed by enantioselective analytical methodologies to accurately measure the enantiomeric fraction (EF. The enantioselective monitoring of microcosms and laboratory-scale experiments with different environmental matrices is herein reported. Thus, this review focuses on the importance of evaluating the EF variation during biodegradation studies of chiral pharmaceuticals, drugs of abuse, and agrochemicals and has implications for the understanding of the environmental fate of chiral pollutants.
Compound process fuel cycle concept

International Nuclear Information System (INIS)

Ikegami, Tetsuo

2005-01-01

Mass flow of light water reactor spent fuel for a newly proposed nuclear fuel cycle concept 'Compound Process Fuel Cycle' has been studied in order to assess the capacity of the concept for accepting light water reactor spent fuels, taking an example for boiling water reactor mixed oxide spent fuel of 60 GWd/t burn-up and for a fast reactor core of 3 GW thermal output. The acceptable heavy metal of boiling water reactor mixed oxide spent fuel is about 3.7 t/y/reactor while the burn-up of the recycled fuel is about 160 GWd/t and about 1.6 t/y reactor with the recycled fuel burn-up of about 300 GWd/t, in the case of 2 times recycle and 4 times recycle respectively. The compound process fuel cycle concept has such flexibility that it can accept so much light water reactor spent fuels as to suppress the light water reactor spent fuel pile-up if not so high fuel burn-up is expected, and can aim at high fuel burn-up if the light water reactor spent fuel pile-up is not so much. Following distinctive features of the concept have also been revealed. A sort of ideal utilization of boiling water reactor mixed oxide spent fuel might be achieved through this concept, since both plutonium and minor actinide reach equilibrium state beyond 2 times recycle. Changes of the reactivity coefficients during recycles are mild, giving roughly same level of reactivity coefficients as the conventional large scale fast breeder core. Both the radio-activity and the heat generation after 4 year cooling and after 4 times recycle are less than 2.5 times of those of the pre recycle fuel. (author)
Biodegradation of low-density polyethylene (LDPE by mixed culture of Lysinibacillus xylanilyticus and Aspergillus niger in soil.

Directory of Open Access Journals (Sweden)

Atefeh Esmaeili

Full Text Available In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR, x-ray diffraction (XRD and scanning electron microscopy (SEM were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source.
Biodegradation of Low-Density Polyethylene (LDPE) by Mixed Culture of Lysinibacillus xylanilyticus and Aspergillus niger in Soil

Science.gov (United States)

Esmaeili, Atefeh; Pourbabaee, Ahmad Ali; Alikhani, Hossein Ali; Shabani, Farzin; Esmaeili, Ensieh

2013-01-01

In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE) were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR), x-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source. PMID:24086254
Biodegradation studies of diesel-contaminated soils and sediments

International Nuclear Information System (INIS)

Schlauch, M.; Clark, D.

1992-01-01

Radian Corporation is currently remediating the Atchison, Topeka and Sante Fe Railway Superfund site in Clovis, New Mexico. Biodegradation of the petroleum hydrocarbon-contaminated soils and sediments was chosen as the remedial alternative. In order to evaluate the optimum conditions for full-scale bioremediation at this site, Radian designed and implemented various laboratory and field studies. The initial laboratory treatability study was conducted to determine if hydrocarbons in both soils and sediments could be biodegraded using indigenous microorganisms, and determine that the soil were biodegradable, while the sediments were not due to inhibitory factors. To further evaluate the biodegradability6 of the sediments, a laboratory study was initiated which introduced chloride-resistant microbes. The study showed that the sediment bioremediation was possibly by utilizing these microbes; however, the cost was not favorable. Finally, a field plot study was initiated to determine how soil biodegradation would proceed in field conditions, to optimize influencing factors such as moisture and nutrient levels and bioseed addition, and to investigate alternate methods of bioremediating the sediments. Results showed that hydrocarbons in the soils biodegraded much faster in the field than in the lab, and that hydrocarbons in sediments applied to biotreated soils containing acclimated microorganisms were successfully biodegraded
A novel biodegradable nicotinic acid/calcium phosphate composite coating on Mg-3Zn alloy

Energy Technology Data Exchange (ETDEWEB)

Song, Yingwei, E-mail: ywsong@imr.ac.cn; Shan, Dayong; Han, En-Hou

2013-01-01

A novel biodegradable composite coating is prepared to reduce the biodegradation rate of Mg-3Zn alloy. The Mg-3Zn substrate is first immersed into 0.02 mol L{sup -1} nicotinic acid (NA) solution, named as vitamin B{sub 3}, to obtain a pretreatment film, and then the electrodeposition of calcium phosphate coating with ultrasonic agitation is carried out on the NA pretreatment film to obtain a NA/calcium phosphate composite coating. Surface morphology is observed by scanning electron microscopy (SEM). Chemical composition is determined by X-ray diffraction (XRD) and EDX. Protection property of the coatings is evaluated by electrochemical tests. The biodegradable behavior is investigated by immersion tests. The results indicate that a thin but compact bottom layer can be obtained by NA pretreatment. The electrodeposition calcium phosphate coating consists of many flake particles and ultrasonic agitation can greatly improve the compactness of the coating. The composite coating is biodegradable and can reduce the biodegradation rate of Mg alloys in stimulated body fluid (SBF) for twenty times. The biodegradation process of the composite coating can be attributed to the gradual dissolution of the flake particles into chippings. - Highlights: Black-Right-Pointing-Pointer NA/calcium phosphate composite coating is prepared to protect Mg-3Zn alloy implant. Black-Right-Pointing-Pointer Nicotinic acid (vitamin B{sub 3}) is available to obtain a protective bottom film. Black-Right-Pointing-Pointer Ultrasonic agitation greatly improves the compactness of calcium phosphate coating. Black-Right-Pointing-Pointer The composite coating can reduce the biodegradation rate of Mg-3Zn twenty times. Black-Right-Pointing-Pointer The composite coating is biodegraded by the dissolution of flakes into chippings.
A model framework to describe growth-linked biodegradation of trace-level pollutants in the presence of coincidental carbon substrates and microbes.

Science.gov (United States)

Liu, Li; Helbling, Damian E; Kohler, Hans-Peter E; Smets, Barth F

2014-11-18

Pollutants such as pesticides and their degradation products occur ubiquitously in natural aquatic environments at trace concentrations (μg L(-1) and lower). Microbial biodegradation processes have long been known to contribute to the attenuation of pesticides in contaminated environments. However, challenges remain in developing engineered remediation strategies for pesticide-contaminated environments because the fundamental processes that regulate growth-linked biodegradation of pesticides in natural environments remain poorly understood. In this research, we developed a model framework to describe growth-linked biodegradation of pesticides at trace concentrations. We used experimental data reported in the literature or novel simulations to explore three fundamental kinetic processes in isolation. We then combine these kinetic processes into a unified model framework. The three kinetic processes described were: the growth-linked biodegradation of micropollutant at environmentally relevant concentrations; the effect of coincidental assimilable organic carbon substrates; and the effect of coincidental microbes that compete for assimilable organic carbon substrates. We used Monod kinetic models to describe substrate utilization and microbial growth rates for specific pesticide and degrader pairs. We then extended the model to include terms for utilization of assimilable organic carbon substrates by the specific degrader and coincidental microbes, growth on assimilable organic carbon substrates by the specific degrader and coincidental microbes, and endogenous metabolism. The proposed model framework enables interpretation and description of a range of experimental observations on micropollutant biodegradation. The model provides a useful tool to identify environmental conditions with respect to the occurrence of assimilable organic carbon and coincidental microbes that may result in enhanced or reduced micropollutant biodegradation.
Experimental studies of biodegradation of asphalt by microorganisms

International Nuclear Information System (INIS)

Mine, Tatsuya; Mihara, Morihiro; Ooi, Takao; Lin, Kong-hua; Kawakami, Yasushi

2000-04-01

On the geological disposal system of the radioactive wastes, the activities of the microorganisms that could degrade the asphalt might be significant for the assessment of the system performance. As the main effects of the biodegradation of the asphalt, the fluctuation of leaching behavior of the nuclides included in asphalt waste has been indicated. In this study, the asphalt biodegradation test was carried out. The microorganism of which asphalt degradation ability was comparatively higher under aerobic condition and anaerobic condition was used. The asphalt biodegradation rate was calculated and it was evaluated whether the asphalt biodegradation in this system could occur. The results show that the asphalt biodegradation rate under anaerobic and high alkali condition will be 300 times lower than under aerobic and neutral pH. (author)
Radiation processing of polyolefins and compounds

International Nuclear Information System (INIS)

Barlow, A.; Biggs, J.; Maringer, M.

1977-01-01

Many properties of polyethylene and its copolymers are enhanced by crosslinking. This can be accomplished through the use of either peroxides or radiation. Crosslinking with peroxides is performed at elevated temperatures generally under pressure; catalyst residues remain in the product which have an adverse effect on electrical and possibly other properties. Radiation crosslinking, on the other hand, is performed under ambient conditions, is essentially free of pollution and offers lower overall production costs due to increased processing speed. A cost analysis of the two crosslinking processes applied to wire and cable coating is included. The advantages of radiation curing can be negated by processing problems which lead to inadequate product properties. Problems are described which may be encountered in developing a flame retardant, radiation curable compound for wire and cable coating. Of particular concern is the generation of a microporous structure which is accentuated by the presence of flame retardant ingredients and the absence of pressure inherent to the peroxide curing process. The procedures involved in solving these problems are briefly described. (author)

Some links on this page may take you to non-federal websites. Their policies may differ from this site.