WorldWideScience

Sample records for forming biodegradable chitosan-hyaluronic

  1. [Preparation and physicochemical property of carboxymethyl-chitosan/hyaluronic acid poly(vinyl alcohol) blend membrane].

    Science.gov (United States)

    Liu, Wen; Li, Shuning; Chang, Jing; Han, Baoqin; Liu, Wanshun

    2009-08-01

    To prepare carboxymethyl-chitosan/hyaluronic acid/poly(vinyl alcohol) (CHP) blend membrane, evaluate its physicochemical properties and intraocular biocompatibility and to investigate its feasibility to be applied to glaucoma filtering surgery. CHP blend membrane was prepared using solution casting method after blending carboxymethyl-chitosan, HA and poly(vinyl alcohol) in a proportion of 5 : 4 : 1 (M/M). Its water absorption rate, swelling rate, permeability, and mechanical properties were detected. Subconjunctival fibroblasts separated from subconjunctival tissue of New Zealand white rabbits were cultured, and the cells at passage 4 were cultured on cell culture plate with or without the CHP blend membrane, serving as the experimental group and the control group, respectively. Effect of the CHP blend membrane on the subconjunctival fibroblasts was tested by MTT method 24, 48, and 72 hours after culture. Six New Zealand white rabbits were randomly divided into two groups (n = 3 rabbits per group), and the CHP blend membrane and SK gel were implanted into the rabbits' subconjunctival space and anterior chamber in the experimental group and the control group, respectively. Slit lamp observation and binocular reaction record were conducted 1, 3, 5, 9, 11, 20, 30, 45, and 60 days after operation. Corneal tissue harvested from the experimental group was observed using scanning electron microscope 15 days after operation to study ophthalmic biocompatibility and biodegradability. The water absorption rate and the swelling rate of the CHP blend membrane was 83.8% +/- 1.3% and 3.59 +/- 0.50, respectively. The tensile strength of the dry and the wet CHP blend membrane was (20.59 +/- 1.73) and (0.51 +/- 0.13) MPa, respectively. The breaking elongation rate of the dry and the wet CHP blend membrane was 10.69% +/- 1.16% and 53.15% +/- 2.46%, respectively. The CHP blend membrane had good permeability to NaCl and L-tyrosine. Absorbance (A) value of the experimental group 24, 48

  2. Chitosan/Hyaluronic Acid Nanoparticles: Rational Design Revisited for RNA Delivery.

    Science.gov (United States)

    Lallana, Enrique; Rios de la Rosa, Julio M; Tirella, Annalisa; Pelliccia, Maria; Gennari, Arianna; Stratford, Ian J; Puri, Sanyogitta; Ashford, Marianne; Tirelli, Nicola

    2017-07-03

    Chitosan/hyaluronic acid (HA) nanoparticles can be used to deliver an RNA/DNA cargo to cells overexpressing HA receptors such as CD44. For these systems, unequivocal links have not been established yet between chitosan macromolecular (molecular weight; degree of deacetylation, i.e., charge density) and nanoparticle variables (complexation strength, i.e., stability; nucleic acid protection; internalization rate) on one hand, and transfection efficiency on the other hand. Here, we have focused on the role of avidity on transfection efficiency in the CD44-expressing HCT-116 as a cellular model; we have employed two differently sized payloads (a large luciferase-encoding mRNA and a much smaller anti-Luc siRNA), and a small library of chitosans (variable molecular weight and degree of deactylation). The RNA avidity for chitosan showed-as expected-an inverse relationship: higher avidity-higher polyplex stability-lower transfection efficiency. The avidity of chitosan for RNA appears to lead to opposite effects: higher avidity-higher polyplex stability but also higher transfection efficiency. Surprisingly, the best transfecting particles were those with the lowest propensity for RNA release, although this might be a misleading relationship: for example, the same macromolecular parameters that increase avidity can also boost chitosan's endosomolytic activity, with a strong enhancement in transfection. The performance of these nonviral vectors appears therefore difficult to predict simply on the basis of carrier- or payload-related variables, and a more holistic consideration of the journey of the nanoparticle, from cell uptake to cytosolic bioavailability of payload, is needed. It is also noteworthy that the nanoparticles used in this study showed optimal performance under slightly acidic conditions (pH 6.4), which is promising for applications in a tumoral extracellular environment. It is also worth pointing out that under these conditions we have for the first time

  3. Enhanced antiadhesive properties of chitosan/hyaluronic acid polyelectrolyte multilayers driven by thermal annealing: Low adherence for mammalian cells and selective decrease in adhesion for Gram-positive bacteria.

    Science.gov (United States)

    Muzzio, Nicolás E; Pasquale, Miguel A; Diamanti, Eleftheria; Gregurec, Danijela; Moro, Marta Martinez; Azzaroni, Omar; Moya, Sergio E

    2017-11-01

    The development of antifouling coatings with restricted cell and bacteria adherence is fundamental for many biomedical applications. A strategy for the fabrication of antifouling coatings based on the layer-by-layer assembly and thermal annealing is presented. Polyelectrolyte multilayers (PEMs) assembled from chitosan and hyaluronic acid were thermally annealed in an oven at 37°C for 72h. The effect of annealing on the PEM properties and topography was studied by atomic force microscopy, ζ-potential, circular dichroism and contact angle measurements. Cell adherence on PEMs before and after annealing was evaluated by measuring the cell spreading area and aspect ratio for the A549 epithelial, BHK kidney fibroblast, C2C12 myoblast and MC-3T3-E1 osteoblast cell lines. Chitosan/hyaluronic acid PEMs show a low cell adherence that decreases with the thermal annealing, as observed from the reduction in the average cell spreading area and more rounded cell morphology. The adhesion of S. aureus (Gram-positive) and E. coli (Gram-negative) bacteria strains was quantified by optical microscopy, counting the number of colony-forming units and measuring the light scattering of bacteria suspension after detachment from the PEM surface. A 20% decrease in bacteria adhesion was selectively observed in the S. aureus strain after annealing. The changes in mammalian cell and bacteria adhesion correlate with the changes in topography of the chitosan/hyaluronic PEMs from a rough fibrillar 3D structure to a smoother and planar surface after thermal annealing. Copyright © 2017. Published by Elsevier B.V.

  4. A surface-mediated siRNA delivery system developed with chitosan/hyaluronic acid-siRNA multilayer films through layer-by-layer self-assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Lijuan [Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062 (China); Suzhou Novovita Bio-products Co., Ltd., Suzhou 215300 (China); Wu, Changlin, E-mail: Ph.Dclwu1314@sina.cn [Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062 (China); Suzhou Novovita Bio-products Co., Ltd., Suzhou 215300 (China); Liu, Guangwan [Suzhou Novovita Bio-products Co., Ltd., Suzhou 215300 (China); Liao, Nannan [Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062 (China); Suzhou Novovita Bio-products Co., Ltd., Suzhou 215300 (China); Zhao, Fang; Yang, Xuxia; Qu, Hongyuan [Suzhou Novovita Bio-products Co., Ltd., Suzhou 215300 (China); Peng, Bo [Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062 (China); Chen, Li [Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062 (China); Suzhou Novovita Bio-products Co., Ltd., Suzhou 215300 (China); Yang, Guang [Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062 (China)

    2016-12-15

    Highlights: • We prepared Chitosan/Hyaluronic acid-siRNA multilayer as carrier to effectively load and protect siRNAs. • The stability and integrity of the siRNA was verified in the siRNA-loaded films. • The siRNA-loaded films showed good cells adhesion and gene silencing effect in eGFP-HEK 293T cells. • This is a new type of surface-mediated non-viral multilayer films. - Abstract: siRNA delivery remains highly challenging because of its hydrophilic and anionic nature and its sensitivity to nuclease degradation. Effective siRNA loading and improved transfection efficiency into cells represents a key problem. In our study, we prepared Chitosan/Hyaluronic acid-siRNA multilayer films through layer-by-layer self-assembly, in which siRNAs can be effectively loaded and protected. The construction process was characterized by FTIR, {sup 13}C NMR (CP/MAS), UV–vis spectroscopy, and atomic force microscopy (AFM). We presented the controlled-release performance of the films during incubation in 1 M NaCl solution for several days through UV–vis spectroscopy and polyacrylamide gel electrophoresis (PAGE). Additionally, we verified the stability and integrity of the siRNA loaded on multilayer films. Finally, the biological efficacy of the siRNA delivery system was evaluated via cells adhesion and gene silencing analyses in eGFP-HEK 293T cells. This new type of surface-mediated non-viral multilayer films may have considerable potential in the localized and controlled-release delivery of siRNA in mucosal tissues, and tissue engineering application.

  5. Biodegradation testing of TMI-2 EPICOR-II waste forms

    International Nuclear Information System (INIS)

    Rogers, R.D.; McConnell, J.W. Jr.

    1988-06-01

    ASTM biodegradation tests were conducted on waste forms containing high specific activity ion exchange resins from EPICOR-II prefilters. Those tests were part of a program to test waste forms in accordance with the NRC Branch Technical Position on Waste Form. Small waste forms were manufactured using two different solidification agents, Portland Type I-II cement and vinyl ester-styrene (VES). Ion exchange material was taken from two EPICOR-II prefilters; PF-7, which contained all organic material, and PF-20, which contained organic resins and a layer of inorganic zeolites. Test results showed that the VES waste forms supported microbial growth, while cement waste forms did not support that growth. Growth was also observed adjacent to some VES waste forms. Radiation levels found in the ion exchange resins used in this study were not found to inhibit microbial growth. The extent of degradation of the waste forms could not be determined using the ASTM tests specified by the NRC Branch Technical Position on Waste Form. As a result of this work, a different testing methodology is recommended, which would provide direct verification of waste form capabilities. That methodology would evaluate solidification materials without using the ASTM procedures or subsequent compression testing. The proposed tests would provide exposure to a wide range of microbial species, use appropriately sized specimens, provide for possible use of alternate carbon sources, and extend the test length. Degradation would be determined directly by measuring metabolic activity or specimen weight loss. 16 refs., 15 figs., 3 tabs

  6. Hematopoietic stem cell capture and directional differentiation into vascular endothelial cells for metal stent-coated chitosan/hyaluronic acid loading CD133 antibody.

    Science.gov (United States)

    Zhang, Shixuan; Zhang, Fan; Feng, Bo; Fan, Qingyu; Yang, Feng; Shang, Debin; Sui, Jinghan; Zhao, Hong

    2015-03-01

    A series of metal stents coated with chitosan/hyaluronic acid (CS/HA) loading antibodies by electrostatic self-assembled method were prepared, and the types of cells captured by antibodies and their differentiation in vascular endothelial cells (ECs) evaluated by molecular biology and scanning electron microscope. The results showed that CD133 stent can selectively capture hematopoietic stem cells (HSC),which directionally differentiate into vascular ECs in peripheral blood by (CS/HA) induction, and simultaneously inhibit migration and proliferation of immune cells and vascular smooth muscle cells (MCs). CD34 stent can capture HSC, hematopoietic progenitor cells that differentiate into vascular ECs and immune cells, promoting smooth MCs growth, leading to thrombosis, inflammation, and rejection. CD133 stent can be implanted into miniature pig heart coronary and can repair vascular damage by capturing own HSC, thus contributing to the rapid natural vascular repair, avoiding inflammation and rejection, thrombosis and restenosis. These studies demonstrated that CD133 stent of HSC capture will be an ideal coated metal stent providing a new therapeutic approach for cardiovascular and cerebrovascular disease.

  7. 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

  8. Clay Nanoparticles Elicit Long-Term Immune Responses by Forming Biodegradable Depots for Sustained Antigen Stimulation.

    Science.gov (United States)

    Chen, Weiyu; Zuo, Huali; Li, Bei; Duan, Chengcheng; Rolfe, Barbara; Zhang, Bing; Mahony, Timothy J; Xu, Zhi Ping

    2018-05-01

    Nanomaterials have been widely tested as new generation vaccine adjuvants, but few evoke efficient immunoreactions. Clay nanoparticles, for example, layered double hydroxide (LDH) and hectorite (HEC) nanoparticles, have shown their potent adjuvanticity in generating effective and durable immune responses. However, the mechanism by which clay nanoadjuvants stimulate the immune system is not well understood. Here, it is demonstrated that LDH and HEC-antigen complexes form loose agglomerates in culture medium/serum. They also form nodules with loose structures in tissue after subcutaneous injection, where they act as a depot for up to 35 d. More importantly, clay nanoparticles actively and continuously recruit immune cells into the depot for up to one month, and stimulate stronger immune responses than FDA-approved adjuvants, Alum and QuilA. Sustained antigen release is also observed in clay nanoparticle depots, with 50-60% antigen released after 35 d. In contrast, Alum-antigen complexes show minimal antigen release from the depot. Importantly, LDH and HEC are more effective than QuilA and Alum in promoting memory T-cell proliferation. These findings suggest that both clay nanoadjuvants can serve as active vaccine platforms for sustained and potent immune responses. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Bioactivity of freeze-dried platelet-rich plasma in an adsorbed form on a biodegradable polymer material.

    Science.gov (United States)

    Nakajima, Yu; Kawase, Tomoyuki; Kobayashi, Mito; Okuda, Kazuhiro; Wolff, Larry F; Yoshie, Hiromasa

    2012-01-01

    Owing to the necessity for the immediate preparation from patients' blood, autologous platelet-rich plasma (PRP) limits its clinical applicability. To address this concern and respond to emergency care and other unpredictable uses, we have developed a freeze-dried PRP in an adsorbed form on a biodegradable polymer material (Polyglactin 910). On the polymer filaments of PRP mesh, which was prepared by coating the polymer mesh with human fresh PRP and subsequent freeze-drying, platelets were incorporated, and related growth factors were preserved at high levels. This new PRP mesh preparation significantly and reproducibly stimulated the proliferation of human periodontal ligament cells in vitro and neovascularization in a chorioallantoic membrane assay. A full-thickness skin defect model in a diabetic mouse demonstrated the PRP mesh, although prepared from human blood, substantially facilitated angiogenesis, granulation tissue formation, and re-epithelialization without inducing severe inflammation in vivo. These data demonstrate that our new PRP mesh preparation functions as a bioactive material to facilitate tissue repair/regeneration. Therefore, we suggest that this bioactive material, composed of allogeneic PRP, could be clinically used as a promising alternative in emergency care or at times when autologous PRP is not prepared immediately before application.

  10. 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. ...

  11. 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

  12. Oil biodegradation

    NARCIS (Netherlands)

    Rahsepar, Shokouhalsadat; Langenhoff, Alette A.M.; Smit, Martijn P.J.; Eenennaam, van Justine S.; Murk, Tinka; Rijnaarts, Huub H.M.

    2017-01-01

    During the Deepwater Horizon (DwH) oil spill, interactions between oil, clay particles and marine snow lead to the formation of aggregates. Interactions between these components play an important, but yet not well understood, role in biodegradation of oil in the ocean water. The aim of this study

  13. Biodegradable Polydepsipeptides

    Directory of Open Access Journals (Sweden)

    Jintang Guo

    2009-02-01

    Full Text Available This paper reviews the synthesis, characterization, biodegradation and usage of bioresorbable polymers based on polydepsipeptides. The ring-opening polymerization of morpholine-2,5-dione derivatives using organic Sn and enzyme lipase is discussed. The dependence of the macroscopic properties of the block copolymers on their structure is also presented. Bioresorbable polymers based on polydepsipeptides could be used as biomaterials in drug controlled release, tissue engineering scaffolding and shape-memory materials.

  14. 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...

  15. 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...

  16. 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.

  17. 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.

  18. Acute toxicity evaluation of in situ gel-forming controlled drug delivery system based on biodegradable poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) copolymer

    International Nuclear Information System (INIS)

    Fang Fang; Gong Changyang; Dong Pengwei; Fu Shaozhi; Gu Yingchun; Guo Gang; Zhao Xia; Wei Yuquan; Qian Zhiyong

    2009-01-01

    In this paper, biodegradable poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL) triblock copolymer was synthesized, and was characterized by FTIR, 1 H-NMR and GPC. The PCL-PEG-PCL/dimethyl sulfoxide (DMSO) solution displayed in situ gelling behavior when subcutaneously injected into the body. Toxicity tests and a histopathological study were performed in BALB/c mice. We focused mainly on acute organ toxicity of BALB/c mice by subcutaneous injection. In the acute toxicity test, the dose of subcutaneous injection was 5 g/kg body weight (b.w.), and the mice were observed continuously for 14 days. For the histopathological study, samples including heart, lung, liver, kidneys, spleen, stomach and intestine were histochemically prepared and stained with hematoxylin-eosin for histopathological examination. No mortality or significant signs of toxicity were observed during the whole observation period, and there is no significant lesion to be shown in histopathological study of major organs in the mice. Therefore, the maximal tolerance dose of dimethyl sulfoxide (DMSO) solution of PCL-PEG-PCL copolymer by subcutaneous injection was calculated to be higher than 5 g/kg b.w. Therefore, the PCL-PEG-PCL/DMSO system was thought to be non-toxic after subcutaneous injection, and it might be a candidate for an in situ gelling controlled drug delivery system.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Rheological and structural characterisation of film-forming solutions and biodegradable edible film made from kefiran as affected by various plasticizer types.

    Science.gov (United States)

    Ghasemlou, Mehran; Khodaiyan, Faramarz; Oromiehie, Abdulrasoul

    2011-11-01

    The rheological properties of kefiran film-forming solutions, as well as the structural characterisation of the resulting films, were investigated as a function of various plasticizer types. The behaviours of the storage (G') and loss (G″) moduli as a function of frequency were typical of gel-like material, with the G' higher than the G″. Kefiran-based films, which may find application as edible films, were prepared by a casting and solvent-evaporation method. Possible interaction between the adjacent chains in the kefiran polymer and various plasticizers was proven by Fourier-transform infrared spectroscopy (FT-IR). The crystallinity of plasticized kefiran film was also analysed using X-ray diffraction (XRD); this revealed an amorphous-crystalline structure. These results were explained by the film's microstructure, which was analysed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The present study has helped determine possible interactions of kefiran, plasticizer and water molecules in determining film properties. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. 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

  6. 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

  7. 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....

  8. 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

  9. 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

  10. 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...

  11. 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.

  12. 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.

  13. Grey water biodegradability

    NARCIS (Netherlands)

    Abu Ghunmi, L.; Zeeman, G.; Fayyad, M.; Van Lier, J.B.

    2010-01-01

    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

  14. Grey water biodegradability

    NARCIS (Netherlands)

    Abu Ghunmi, L.; Zeeman, G.; Fayyad, M.; Lier, van J.B.

    2011-01-01

    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

  15. 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.

  16. Safe biodegradable fluorescent particles

    Science.gov (United States)

    Martin, Sue I [Berkeley, CA; Fergenson, David P [Alamo, CA; Srivastava, Abneesh [Santa Clara, CA; Bogan, Michael J [Dublin, CA; Riot, Vincent J [Oakland, CA; Frank, Matthias [Oakland, CA

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  17. 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.

  18. Coatings and Biodegradable and Bioasorbable Films

    Science.gov (United States)

    2006-12-28

    Dielectric Spectroscopy ," Polymers for Biomedical Applications Symposium, ACS Fall 2006 Meeting, San Francisco, CA. 25 Novel Biodegradable Films Based on...groups upon cross-linking with HDI. The Figl2. Positron annihilation assessment hydroxyl groups are known to form fairly strong of free volume behavior of...1.26 e volume is accumulated upon cooling. Probing free- "A volume with positron life time spectroscopy 1.25 (PALS) showed that indeed, cross-linked

  19. Silica in situ enhanced PVA/chitosan biodegradable films for food packages.

    Science.gov (United States)

    Yu, Zhen; Li, Baoqiang; Chu, Jiayu; Zhang, Peifeng

    2018-03-15

    Non-degradable plastic food packages threaten the security of environment. The cost-effective and biodegradable polymer films with good mechanical properties and low permeability are very important for food packages. Among of biodegradable polymers, PVA/chitosan (CS) biodegradable films have attracted considerable attention because of feasible film forming ability. However, PVA/CS biodegradable films suffered from poor mechanical properties. To improve mechanical properties of PVA/CS biodegradable films, we developed SiO 2 in situ to enhance PVA/CS biodegradable films via hydrolysis of sodium metasilicate in presence of PVA and chitosan solution. The tensile strength of PVA/CS biodegradable films was improved 45% when 0.6 wt.% SiO 2 was incorporated into the films. Weight loss of PVA/CS biodegradable films was 60% after 30 days in the soil. The permeability of oxygen and moisture of PVA/CS biodegradable films was reduced by 25.6% and 10.2%, respectively. SiO 2 in situ enhanced PVA/CS biodegradable films possessed not only excellent mechanical properties, but also barrier of oxygen and water for food packages to extend the perseveration time. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Biodegradation of Polypropylene Nonwovens

    Science.gov (United States)

    Keene, Brandi Nechelle

    The primary aim of the current research is to document the biodegradation of polypropylene nonwovens and filament under composting environments. To accelerate the biodegradat ion, pre-treatments and additives were incorporated into polypropylene filaments and nonwovens. The initial phase (Chapter 2) of the project studied the biodegradation of untreated polypropylene with/without pro-oxidants in two types of composting systems. Normal composting, which involved incubation of samples in food waste, had little effect on the mechanical properties of additive-free spunbond nonwovens in to comparison prooxidant containing spunbond nonwovens which were affected significantly. Modified composting which includes the burial of samples with food and compressed air, the polypropylene spunbond nonwovens with/without pro-oxidants displayed an extreme loss in mechanical properties and cracking on the surface cracking. Because the untreated spunbond nonwovens did not completely decompose, the next phase of the project examined the pre-treatment of gamma-irradiation or thermal aging prior to composting. After exposure to gamma-irradiation and thermal aging, polypropylene is subjected to oxidative degradation in the presence of air and during storage after irradiat ion. Similar to photo-oxidation, the mechanism of gamma radiation and thermal oxidative degradation is fundamentally free radical in nature. In Chapter 3, the compostability of thermal aged spunbond polypropylene nonwovens with/without pro-oxidant additives. The FTIR spectrum confirmed oxidat ion of the polypropylene nonwovens with/without additives. Cracking on both the pro-oxidant and control spunbond nonwovens was showed by SEM imaging. Spunbond polypropylene nonwovens with/without pro-oxidants were also preirradiated by gamma rays followed by composting. Nonwovens with/without pro-oxidants were severely degraded by gamma-irradiation after up to 20 kGy exposure as explained in Chapter 4. Furthermore (Chapter 5), gamma

  1. Nanomembranes and Nanofibers from Biodegradable Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Jordi Puiggalí

    2013-09-01

    Full Text Available This review provides a current status report of the field concerning preparation of fibrous mats based on biodegradable (e.g., aliphatic polyesters such as polylactide or polycaprolactone and conducting polymers (e.g., polyaniline, polypirrole or polythiophenes. These materials have potential biomedical applications (e.g., tissue engineering or drug delivery systems and can be combined to get free-standing nanomembranes and nanofibers that retain the better properties of their corresponding individual components. Systems based on biodegradable and conducting polymers constitute nowadays one of the most promising solutions to develop advanced materials enable to cover aspects like local stimulation of desired tissue, time controlled drug release and stimulation of either the proliferation or differentiation of various cell types. The first sections of the review are focused on a general overview of conducting and biodegradable polymers most usually employed and the explanation of the most suitable techniques for preparing nanofibers and nanomembranes (i.e., electrospinning and spin coating. Following sections are organized according to the base conducting polymer (e.g., Sections 4–6 describe hybrid systems having aniline, pyrrole and thiophene units, respectively. Each one of these sections includes specific subsections dealing with applications in a nanofiber or nanomembrane form. Finally, miscellaneous systems and concluding remarks are given in the two last sections.

  2. Biodegradation of biodiesel fuels

    International Nuclear Information System (INIS)

    Zhang, X.; Haws, R.; Wright, B.; Reese, D.; Moeller, G.; Peterson, C.

    1995-01-01

    Biodiesel fuel test substances Rape Ethyl Ester (REE), Rape Methyl Ester (RME), Neat Rape Oil (NR), Say Methyl Ester (SME), Soy Ethyl Ester (SEE), Neat Soy Oil (NS), and proportionate combinations of RME/diesel and REE/diesel were studied to test the biodegradability of the test substances in an aerobic aquatic environment using the EPA 560/6-82-003 Shake Flask Test Method. A concurrent analysis of Phillips D-2 Reference Diesel was also performed for comparison with a conventional fuel. The highest rates of percent CO 2 evolution were seen in the esterified fuels, although no significant difference was noted between them. Ranges of percent CO 2 evolution for esterified fuels were from 77% to 91%. The neat rape and neat soy oils exhibited 70% to 78% CO 2 evolution. These rates were all significantly higher than those of the Phillips D-2 reference fuel which evolved from 7% to 26% of the organic carbon to CO 2 . The test substances were examined for BOD 5 and COD values as a relative measure of biodegradability. Water Accommodated Fraction (WAF) was experimentally derived and BOD 5 and COD analyses were carried out with a diluted concentration at or below the WAF. The results of analysis at WAF were then converted to pure substance values. The pure substance BOD 5 and COD values for test substances were then compared to a control substance, Phillips D-2 Reference fuel. No significant difference was noted for COD values between test substances and the control fuel. (p > 0.20). The D-2 control substance was significantly lower than all test substances for BCD, values at p 5 value

  3. Synthesis of biodegradable styrene copolymers

    OpenAIRE

    Gevers, Dries; Kobben, Stephan; Junkers, Tanja; Copinet, Alain; Buntinx, Mieke; Peeters, Roos

    2017-01-01

    Polystyrene (PS), a versatile polymer with many applications (e.g. packaging) representing about 10% of the total annual polymer consumption, shows practically no biodegradability. In this study a styrene (ST) based copolymer is synthesized and examined regarding its ability to degrade in a composting test. As second monomer, to introduce biodegradable ester groups, 5,6-benzo-2-metylene-dioxepane (BMDO) has been used in radical copolymerization reactions performed in inert and stirred 10 m...

  4. Progress of biodegradable metals

    Directory of Open Access Journals (Sweden)

    Huafang Li

    2014-10-01

    Full Text Available Biodegradable metals (BMs are metals and alloys expected to corrode gradually in vivo, with an appropriate host response elicited by released corrosion products, then dissolve completely upon fulfilling the mission to assist with tissue healing with no implant residues. In the present review article, three classes of BMs have been systematically reviewed, including Mg-based, Fe-based and Zn-based BMs. Among the three BM systems, Mg-based BMs, which now have several systems reported the successful of clinical trial results, are considered the vanguards and main force. Fe-based BMs, with pure iron and Fe–Mn based alloys as the most promising, are still on the animal test stage. Zn-based BMs, supposed to have the degradation rate between the fast Mg-based BMs and the slow Fe-based BMs, are a rising star with only several reports and need much further research. The future research and development direction for the BMs are proposed, based on the clinical requirements on controllable degradation rate, prolonged mechanical stability and excellent biocompatibility, by optimization of alloy composition design, regulation on microstructure and mechanical properties, and following surface modification.

  5. Treatment of biodegradable material

    Energy Technology Data Exchange (ETDEWEB)

    Pannell, S D; Greenshields, R N

    1981-05-13

    Biodegradable effluents, e.g. containing carbohydrates and/or proteins, were treated by passing up a tower fermenter tapered at the top and with an aspect ratio of greater than or equal to 3:1. A flocculant microorganism aerobically digested the effluent in the tower and the mixture of treated medium, gas, and surplus microorganism was discharged through an inverted-U-shaped outlet at the top. After separation of the biomass, which could be used as an animal feed, the purified effluent could be discharged. A milk-processing effluent (2.5 g solids/l, of which 65% was sucrose and 35% milk solids) was treated in a fermentation tower (aspect ratio 10:1). Aspergillus niger in the tower readily digested sucrose and at least some lactose as air and NH/sub 4/NO/sub 3/ were added. At least 90% of the casein was trapped by the microorganisms and discharged with them from the tower. The microrganisms were separated with a vibrating sieve giving a final discharged liquid containing 0.2 g solids/l.

  6. 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)

  7. 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.

  8. User’s Guide for Biodegradation Reactions in TMVOCBio

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yoojin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Battistelli, Alfredo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-08-31

    TMVOCBio is an extended version of the TMVOC numerical reservoir simulator, with the capability of simulating multiple biodegradation reactions mediated by different microbial populations or based on different redox reactions, thus involving different electron acceptors. This modeling feature is implemented within the existing TMVOC module in iTOUGH2. TMVOCBio, originally developed by Battistelli (2003; 2004), uses a general modified form of the Monod kinetic rate equation to simulate biodegradation reactions, which effectively simulates the uptake of a substrate while accounting for various limiting factors (i.e., the limitation by substrate, electron acceptor, or nutrients). Two approaches are included: 1) a multiple Monod kinetic rate equation, which assumes all the limiting factors simultaneously affect the substrate uptake rate, and 2) a minimum Monod model, which assumes that the substrate uptake rate is controlled by the most limiting factor among those acting for the specific substrate. As the limiting factors, biomass growth inhibition, toxicity effects, as well as competitive and non-competitive inhibition effects are included. The temperature and moisture dependence of biodegradation reactions is also considered. This report provides mathematical formulations and assumptions used for modeling the biodegradation reactions, and describes additional modeling capabilities. Detailed description of input format for biodegradation reactions is presented along with sample problems.

  9. 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.

  10. Biodegradation testing of solidified low-level waste streams

    International Nuclear Information System (INIS)

    Piciulo, P.L.; Shea, C.E.; Barletta, R.E.

    1985-05-01

    The NRC Technical Position on Waste Form (TP) specifies that waste should be resistant to biodegradation. The methods recommended in the TP for testing resistance to fungi, ASTM G21, and for testing resistance to bacteria, ASTM G22, were carried out on several types of solidified simulated wastes, and the effect of microbial activity on the mechanical strength of the materials tested was examined. The tests are believed to be sufficient for distinguishing between materials that are susceptible to biodegradation and those that are not. It is concluded that failure of these tests should not be regarded of itself as an indication that the waste form will biodegrade to an extent that the form does not meet the stability requirements of 10 CFR Part 61. In the case of failure of ASTM G21 or ASTM G22 or both, it is recommended that additional data be supplied by the waste generator to demonstrate the resistance of the waste form to microbial degradation. To produce a data base on the applicability of the biodegradation tests, the following simulated laboratory-scale waste forms were prepared and tested: boric acid and sodium sulfate evaporator bottoms, mixed-bed bead resins and powdered resins each solidified in asphalt, cement, and vinyl ester-styrene. Cement solidified wastes supported neither fungal nor bacterial growth. Of the asphalt solidified wastes, only the forms of boric acid evaporator bottoms did not support fungal growth. Bacteria grew on all of the asphalt solidified wastes. Cleaning the surface of these waste forms did not affect bacterial growth and had a limited effect on the fungal growth. Only vinyl esterstyrene solidified sodium sulfate evaporator bottoms showed viable fungi cultures, but surface cleaning with solvents eliminated fungal growth in subsequent testing. Some forms of all the waste streams solidified in vinyl ester-styrene showed viable bacteria cultures. 13 refs., 12 tabs

  11. 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

  12. Biodegradable poly(lactic acid)

    Indian Academy of Sciences (India)

    The fabrication of biodegradable poly(lactic acid) (PLA) microspheres containing total alkaloids of Caulis sinomenii was investigated. The formation, diameter, morphology and properties of the microspheres were characterized using Fourier transform infrared spectroscopy (FT–IR), laser particle size analyser and scanning ...

  13. 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.

  14. Biodegradable polymeric prodrugs of naltrexone

    NARCIS (Netherlands)

    Bennet, D.B.; Li, X.; Adams, N.W.; Kim, S.W.; Hoes, C.J.T.; Hoes, C.J.T.; Feijen, Jan

    1991-01-01

    The development of a biodegradable polymeric drug delivery system for the narcotic antagonist naltrexone may improve patient compliance in the treatment of opiate addiction. Random copolymers consisting of the ¿-amino acids N5-(3-hydroxypropyl--glutamine and -leucine were synthesized with equimolar

  15. 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

  16. Effect of stiffness of chitosan-hyaluronic acid dialdehyde hydrogels on the viability and growth of encapsulated chondrocytes.

    Science.gov (United States)

    V Thomas, Lynda; Vg, Rahul; D Nair, Prabha

    2017-11-01

    Substrate elasticity or stiffness can influence the phenotypic and functional characteristics of chondrocytes. This work aimed to study the effect of varying stiffness compositions of a two-component injectable hydrogel based on chitosan (CH) and oxidized hyaluronic acid (HDA) on the growth and functionality of encapsulated chondrocytes. Three different ratios of the gel were prepared (10:1,10:3 and 10:5 CH-HDA) and characterized. The stiffness of the gels was evaluated from the force displacement curves using force spectroscopy AFM analysis. Rabbit articular chondrocytes were harvested and the cells from Passage 2 to 4 were used for the encapsulation study. The viability and ECM production of encapsulated chondrocytes were assessed at 7day, 14day and 28day post culture. The results of the study show that as the ratio of hyaluronic acid dialdehyde component was increased, the stiffness of the gels increased from 130.78±19.83kPa to 181.47±19.77kPa which was also evidenced from the decrease in gelling time. Although there was an increase in the percentage of viable encapsulated cells which also maintained the spherical phenotype in the less stiff gels, decreased expression of ECM markers- Collagen type II and Glycosaminoglycans was observed compared to the stiffer gels. These findings indicate that gel stiffness strongly impacts the chondrocyte microenvironment both in maintenance of phenotypic integrity and ECM production. Copyright © 2017. Published by Elsevier B.V.

  17. Corrosion mechanism applicable to biodegradable magnesium implants

    Energy Technology Data Exchange (ETDEWEB)

    Atrens, Andrej, E-mail: Andrejs.Atrens@uq.edu.au [University of Queensland, Division of Materials, Brisbane, Qld 4072 (Australia); Liu Ming; Zainal Abidin, Nor Ishida [University of Queensland, Division of Materials, Brisbane, Qld 4072 (Australia)

    2011-12-15

    Much of our understanding of the Mg corrosion mechanism is based on research using aggressive chloride based solutions like 3% NaCl, which are appropriate for understand the corrosion for applications such as auto construction. The chloride ions tend to cause break down of the partly protective surface film on the Mg alloy surface. The corrosion rate increases with exposure time until steady state is reached, which may take several weeks. An overview is provided of the aspects which determine the corrosion of Mg alloys: (i) measurement details; (ii) impurity elements Fe, Ni, Cu and Co; (iii) second phases; (iv) surface films and surface condition and (v) stress corrosion cracking (SCC). This understanding is used to help understand Mg corrosion for Mg as a biodegradable implant for medical applications. Solutions that elucidate these applications tend to form surface films and the corrosion rate tends to decrease with immersion time.

  18. 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.

  19. 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.

  20. 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

  1. 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)

  2. 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.

  3. 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.

  4. 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.

  5. High-performance green flexible electronics based on biodegradable cellulose nanofibril paper.

    Science.gov (United States)

    Jung, Yei Hwan; Chang, Tzu-Hsuan; Zhang, Huilong; Yao, Chunhua; Zheng, Qifeng; Yang, Vina W; Mi, Hongyi; Kim, Munho; Cho, Sang June; Park, Dong-Wook; Jiang, Hao; Lee, Juhwan; Qiu, Yijie; Zhou, Weidong; Cai, Zhiyong; Gong, Shaoqin; Ma, Zhenqiang

    2015-05-26

    Today's consumer electronics, such as cell phones, tablets and other portable electronic devices, are typically made of non-renewable, non-biodegradable, and sometimes potentially toxic (for example, gallium arsenide) materials. These consumer electronics are frequently upgraded or discarded, leading to serious environmental contamination. Thus, electronic systems consisting of renewable and biodegradable materials and minimal amount of potentially toxic materials are desirable. Here we report high-performance flexible microwave and digital electronics that consume the smallest amount of potentially toxic materials on biobased, biodegradable and flexible cellulose nanofibril papers. Furthermore, we demonstrate gallium arsenide microwave devices, the consumer wireless workhorse, in a transferrable thin-film form. Successful fabrication of key electrical components on the flexible cellulose nanofibril paper with comparable performance to their rigid counterparts and clear demonstration of fungal biodegradation of the cellulose-nanofibril-based electronics suggest that it is feasible to fabricate high-performance flexible electronics using ecofriendly materials.

  6. CLASSIFICATION OF BIODEGRADABLE POLYMERS

    Directory of Open Access Journals (Sweden)

    I. I. Karpunin

    2015-01-01

    Full Text Available The executed investigations have made it possible to ascertain that a morphological structure of starch granules mainly determine technological peculiarities of starch isolation from raw material, its modification and its later use. Morphological structure of starch granules primarily depends on type of plant starch-containing raw material which has been used for its isolation. Class of raw material exerts a strong impact on the shape and size of the granules. Linear “light” amylose chains and “heavy” amylopectin branch chains form a starch granule ultrastructure. X-ray research has proved that starch granules are characterized by presence of interlacing amorphous and crystalline regions. In this case polymer orientation using stretching of the obtained end product influences on its physical and mechanical  indices which are increasing due to polymer orientation. For the purpose of packaging orientation of polymer films can solve such important problems as significant improvement of operational properties, creation of  thermosetting film materials, improvement of qualitative indices of the recycled film.Results of the conducted research have proved the fact that it is necessary to make changes in technology in order to increase biological degradability of the recycled packaging made from polymers and improve physical and mechanical indices. In this regard film production technology presupposes usage of such substances as stark and others which are characterized by rather large presence of branch chains of molecules and interlacing amorphous and crystalline regions. Such approach makes it possible to obtain after-use package which is strong and quickly degradable by micro-organisms.

  7. Biodegradable Materials and Metallic Implants-A Review.

    Science.gov (United States)

    Prakasam, Mythili; Locs, Janis; Salma-Ancane, Kristine; Loca, Dagnija; Largeteau, Alain; Berzina-Cimdina, Liga

    2017-09-26

    Recent progress made in biomaterials and their clinical applications is well known. In the last five decades, great advances have been made in the field of biomaterials, including ceramics, glasses, polymers, composites, glass-ceramics and metal alloys. A variety of bioimplants are currently used in either one of the aforesaid forms. Some of these materials are designed to degrade or to be resorbed inside the body rather than removing the implant after its function is served. Many properties such as mechanical properties, non-toxicity, surface modification, degradation rate, biocompatibility, and corrosion rate and scaffold design are taken into consideration. The current review focuses on state-of-the-art biodegradable bioceramics, polymers, metal alloys and a few implants that employ bioresorbable/biodegradable materials. The essential functions, properties and their critical factors are discussed in detail, in addition to their challenges to be overcome.

  8. Biodegradable Materials and Metallic Implants—A Review

    Science.gov (United States)

    Prakasam, Mythili; Locs, Janis; Salma-Ancane, Kristine; Loca, Dagnija; Largeteau, Alain; Berzina-Cimdina, Liga

    2017-01-01

    Recent progress made in biomaterials and their clinical applications is well known. In the last five decades, great advances have been made in the field of biomaterials, including ceramics, glasses, polymers, composites, glass-ceramics and metal alloys. A variety of bioimplants are currently used in either one of the aforesaid forms. Some of these materials are designed to degrade or to be resorbed inside the body rather than removing the implant after its function is served. Many properties such as mechanical properties, non-toxicity, surface modification, degradation rate, biocompatibility, and corrosion rate and scaffold design are taken into consideration. The current review focuses on state-of-the-art biodegradable bioceramics, polymers, metal alloys and a few implants that employ bioresorbable/biodegradable materials. The essential functions, properties and their critical factors are discussed in detail, in addition to their challenges to be overcome. PMID:28954399

  9. 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.

  10. Primary biodegradation of petroleum hydrocarbons in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Comber, M.I.H.; Den Haan, K.H.; Djemel, N.; Eadsforth, C.V.; King, D.; Paumen, M.L.; Parkerton, T.; Dmytrasz, B.

    2012-12-15

    This report describes primary biodegradation experiments performed to determine the persistence of higher molecular weight petroleum hydrocarbons in seawater. Results from the biodegradation experiments show that the majority of tested petroleum hydrocarbons have half-lives in seawater less than 60 days.

  11. Simultaneous adsorption and biodegradation of synthetic melanoidin

    African Journals Online (AJOL)

    Being an antioxidant, melanoidin removal through purely biodegradation has been inadequate. Consequently, in the current study, simultaneous adsorption and biodegradation (SAB) was employed in a stirred tank system to remove melanoidin from synthetic wastewater. Mixed microbial consortium was immobilized onto ...

  12. Engineering and functional properties of biodegradable pellets developed from various agro-industrial wastes using extrusion technology.

    Science.gov (United States)

    Jan, Kulsum; Riar, C S; Saxena, D C

    2015-12-01

    Different agro-industrial wastes were mixed with different plasticizers and extruded to form the pellets to be used further for development of biodegradable molded pots. Bulk density and macro-porosity are the important engineering properties used to determine the functional characteristics of the biodegradable pellets viz., expansion volume, water solubility, product colour, flowability and compactness. Significant differences in the functional properties of pellets with varying bulk densities (loose and tapped) and macro-porosities (loose, tapped) were observed. The observed mean bulk density of biodegradable pellets made from different formulations ranged between 0.213 and 0.560 g/ml for loose fill conditions and 0.248 to 0.604 g/ml for tapped fill conditions. Biodegradable pellets bear a good compaction for both loose and tapped fill methods. The mean macro-porosity of biodegradable pellets ranged between 1.19 and 54.48 % for loose fill condition and 0.29 to 53.35 % for tapped fill condition. Hausner ratio (HR) for biodegradable pellets varied from 1.026 to 1.328, indicating a good flowability of biodegradable pellets. Pearson's correlation between engineering properties and functional properties of biodegradable pellets revealed that from engineering properties functional properties can be predicted.

  13. 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.

  14. 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.

  15. Biogeochemistry of anaerobic crude oil biodegradation

    Science.gov (United States)

    Head, Ian; Gray, Neil; Aitken, Caroline; Sherry, Angela; Jones, Martin; Larter, Stephen

    2010-05-01

    Anaerobic degradation of crude oil and petroleum hydrocarbons is widely recognized as a globally significant process both in the formation of the world's vast heavy oil deposits and for the dissipation of hydrocarbon pollution in anoxic contaminated environments. Comparative analysis of crude oil biodegradation under methanogenic and sulfate-reducing conditions has revealed differences not only in the patterns of compound class removal but also in the microbial communities responsible. Under methanogenic conditions syntrophic associations dominated by bacteria from the Syntropheaceae are prevalent and these are likely key players in the initial anaerobic degradation of crude oil alkanes to intermediates such as hydrogen and acetate. Syntrophic acetate oxidation plays an important role in these systems and often results in methanogenesis dominated by CO2 reduction by members of the Methanomicrobiales. By contrast the bacterial communities from sulfate-reducing crude oil-degrading systems were more diverse and no single taxon dominated the oil-degrading sulfate-reducing systems. All five proteobacterial subdivisions were represented with Delta- and Gammaproteobacteria being detected most consistently. In sediments which were pasteurized hydrocarbon degradation continued at a relatively low rate. Nevertheless, alkylsuccinates characteristic of anaerobic hydrocarbon degradation accumulated to high concentrations. This suggested that the sediments harbour heat resistant, possibly spore-forming alkane degrading sulfate-reducers. This is particularly interesting since it has been proposed recently, that spore-forming sulfate-reducing bacteria found in cold arctic sediments may have originated from seepage of geofluids from deep subsurface hydrocarbon reservoirs.

  16. 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

  17. 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.)

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. Biodegradation of PuEDTA and Impacts on Pu Mobility

    International Nuclear Information System (INIS)

    Bolton, H. Jr.; Rai, D.; Xun, L.

    2004-01-01

    The contamination of many DOE sites by Pu presents a long-term problem because of its long half-life (240,000 yrs) and the low drinking water standard ( -12 M). EDTA was co-disposed with radionuclides (e.g., Pu, 60 Co), formed strong complexes, and enhanced radionuclide transport at several DOE sites. Biodegradation of EDTA should decrease Pu mobility. One objective of this project was to determine the biodegradation of EDTA in the presence of PuEDTA complexes. The aqueous system investigated at pH 7 (10 -4 M EDTA and 10 -6 M Pu) contained predominantly Pu(OH) 2 EDTA 2- . The EDTA was degraded at a faster rate in the presence of Pu. As the total concentration of both EDTA and PuEDTA decreased (i.e., 10 -5 M EDTA and 10 -7 M PuEDTA), the presence of Pu decreased the biodegradation rate of the EDTA. It is currently unclear why the concentration of Pu directly affects the increase/decrease in rate of EDTA biodegradation. The soluble Pu concentration decreased, in agreement with thermodynamic predictions, as the EDTA was biodegraded, indicating that biodegradation of EDTA will decrease Pu mobility when the Pu is initially present as Pu(IV)EDTA. A second objective was to investigate how the presence of competing metals, commonly encountered in geologic media, will influence the speciation and biodegradation of Pu(IV)-EDTA. Studies on the solubilities of Fe(OH) 3 (s) and of Fe(OH) 3 (s) plus PuO 2 (am) in the presence of EDTA and as a function of pH showed that Fe(III) out competes the Pu(IV) for the EDTA complex, thereby showing that Pu(IV) will not form stable complexes with EDTA for enhanced transport of Pu in Fe(III) dominated subsurface systems. A third objective is to investigate the genes and enzymes involved in EDTA biodegradation. BNC1 can use EDTA and another synthetic chelating agent nitrilotriacetate (NTA) as sole carbon and nitrogen sources. The same catabolic enzymes are responsible for both EDTA and NTA degradation except that additional enzymes are

  3. 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.

  4. Surface characterization and cytotoxicity response of biodegradable magnesium alloys

    International Nuclear Information System (INIS)

    Pompa, Luis; Rahman, Zia Ur; Munoz, Edgar; Haider, Waseem

    2015-01-01

    Magnesium alloys have raised an immense amount of interest to many researchers because of their evolution as a new kind of third generation materials. Due to their biocompatibility, density, and mechanical properties, magnesium alloys are frequently reported as prospective biodegradable implant materials. Moreover, magnesium alloys experience a natural phenomenon to biodegrade in aqueous solutions due to its corrosion activity, which is excellent for orthopedic and cardiovascular applications. However, a major concern with such alloys is fast and non-uniform corrosion degradation. Controlling the degradation rate in the physiological environment determines the success of biodegradable implants. In this investigation, three different grades of magnesium alloys: AZ31B, AZ91E and ZK60A were studied for their corrosion resistance and biocompatibility. Scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and contact angle meter are used to study surface morphology, chemistry, roughness and wettability, respectively. Additionally, the cytotoxicity of the leached metal ions was evaluated by using a tetrazolium based bio-assay, MTS. - Highlights: • Micro-textured features formed after the anodization of magnesium alloys. • Contact angle increased and surface free energy decreased by anodization. • Corrosion rate increased for anodized surfaces compared to untreated samples. • Cell viability was greater than 75% implying the cytocompatibility of Mg alloys

  5. Surface characterization and cytotoxicity response of biodegradable magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pompa, Luis; Rahman, Zia Ur; Munoz, Edgar; Haider, Waseem, E-mail: haiderw@utpa.edu

    2015-04-01

    Magnesium alloys have raised an immense amount of interest to many researchers because of their evolution as a new kind of third generation materials. Due to their biocompatibility, density, and mechanical properties, magnesium alloys are frequently reported as prospective biodegradable implant materials. Moreover, magnesium alloys experience a natural phenomenon to biodegrade in aqueous solutions due to its corrosion activity, which is excellent for orthopedic and cardiovascular applications. However, a major concern with such alloys is fast and non-uniform corrosion degradation. Controlling the degradation rate in the physiological environment determines the success of biodegradable implants. In this investigation, three different grades of magnesium alloys: AZ31B, AZ91E and ZK60A were studied for their corrosion resistance and biocompatibility. Scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy and contact angle meter are used to study surface morphology, chemistry, roughness and wettability, respectively. Additionally, the cytotoxicity of the leached metal ions was evaluated by using a tetrazolium based bio-assay, MTS. - Highlights: • Micro-textured features formed after the anodization of magnesium alloys. • Contact angle increased and surface free energy decreased by anodization. • Corrosion rate increased for anodized surfaces compared to untreated samples. • Cell viability was greater than 75% implying the cytocompatibility of Mg alloys.

  6. 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

  7. 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.

  8. New perspectives in plastic biodegradation.

    Science.gov (United States)

    Sivan, Alex

    2011-06-01

    During the past 50 years new plastic materials, in various applications, have gradually replaced the traditional metal, wood, leather materials. Ironically, the most preferred property of plastics--durability--exerts also the major environmental threat. Recycling has practically failed to provide a safe solution for disposal of plastic waste (only 5% out of 1 trillion plastic bags, annually produced in the US alone, are being recycled). Since the most utilized plastic is polyethylene (PE; ca. 140 million tons/year), any reduction in the accumulation of PE waste alone would have a major impact on the overall reduction of the plastic waste in the environment. Since PE is considered to be practically inert, efforts were made to isolate unique microorganisms capable of utilizing synthetic polymers. Recent data showed that biodegradation of plastic waste with selected microbial strains became a viable solution. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Engineered biosynthesis of biodegradable polymers.

    Science.gov (United States)

    Jambunathan, Pooja; Zhang, Kechun

    2016-08-01

    Advances in science and technology have resulted in the rapid development of biobased plastics and the major drivers for this expansion are rising environmental concerns of plastic pollution and the depletion of fossil-fuels. This paper presents a broad view on the recent developments of three promising biobased plastics, polylactic acid (PLA), polyhydroxyalkanoate (PHA) and polybutylene succinate (PBS), well known for their biodegradability. The article discusses the natural and recombinant host organisms used for fermentative production of monomers, alternative carbon feedstocks that have been used to lower production cost, different metabolic engineering strategies used to improve product titers, various fermentation technologies employed to increase productivities and finally, the different downstream processes used for recovery and purification of the monomers and polymers.

  10. Biodegradation of surfactant bearing wastes

    International Nuclear Information System (INIS)

    Chitra, S.; Chandran, S.; Sasidhar, P.; Lal, K.B.; Amalraj, R.V.

    1991-01-01

    In nuclear industry, during decontamination of protective wears and contaminated materials, detergents are employed to bring down the level of radioactive contamination within safe limits. However, the surfactant present in these wastes interferes in the chemical treatment process, reducing the decontamination factor. Biodegradation is an efficient and ecologically safe method for surfactant removal. A surfactant degrading culture was isolated and inoculated separately into simulated effluents containing 1% yeast extract and 5-100 ppm sodium lauryl sulphate (SLS) and 1% yeast extract and 5-100 ppm of commercial detergent respectively. The growth of the bacterial culture and the degradation characteristics of the surfactant in the above effluents were monitored under both dynamic and static conditions. (author). 6 refs., 6 figs., 1 tab

  11. 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.

  12. 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.

  13. 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.

  14. 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.)

  15. Formulation and Characterization of Biodegradable Medicated ...

    African Journals Online (AJOL)

    PEG)-600, tributyl citrate, PEG-200, PEG-300, PEG-400, PEG-4000, triethyl citrate and castor oil. The gum formulations were characterized for the following parameters: texture profile analysis (TPA), biodegradation, in vitro drug release using a ...

  16. Engineering and functional properties of biodegradable pellets developed from various agro-industrial wastes using extrusion technology

    OpenAIRE

    Jan, Kulsum; Riar, C. S.; Saxena, D. C.

    2015-01-01

    Different agro-industrial wastes were mixed with different plasticizers and extruded to form the pellets to be used further for development of biodegradable molded pots. Bulk density and macro-porosity are the important engineering properties used to determine the functional characteristics of the biodegradable pellets viz., expansion volume, water solubility, product colour, flowability and compactness. Significant differences in the functional properties of pellets with varying bulk densiti...

  17. Teaching Form as Form

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2012-01-01

    understanding of form per se, or, to use an expression from this text, of form as form. This challenge can be reduced to one question: how can design teaching support students in achieving not only the ability to recognize and describe different form-related concepts in existing design (i.e. analytical...

  18. 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 ...

  19. Biodegradability of polyurethane/polysaccharide blends

    International Nuclear Information System (INIS)

    Mothe, Cheila G.; Leite, Selma G.

    2001-01-01

    Biodegradable polymers for use in environmental waste-management has been the subject of much discussion over the last few years. Polyurethane mixtures with polysaccharide (80/20 and 90/10 w/w ) have been prepared and films obtained. These films were inoculated, according to ASTM G22-76 rule and analysed by thermogravimetry and scanning electronic microscopy (SEM). The results are discussed in terms of thermal degradation and biodegradability. (author)

  20. 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.

  1. 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.

  2. Transformation and biodegradation of 1,2,3-trichloropropane (TCP)

    OpenAIRE

    Samin, Ghufrana; Janssen, Dick B.

    2012-01-01

    Purpose 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 pap...

  3. Evaluation of Biodegradability of Waste Before and After Aerobic Treatment

    Science.gov (United States)

    Suchowska-Kisielewicz, Monika; Jędrczak, Andrzej; Sadecka, Zofia

    2014-12-01

    An important advantage of use of an aerobic biostabilization of waste prior to its disposal is that it intensifies the decomposition of the organic fraction of waste into the form which is easily assimilable for methanogenic microorganisms involved in anaerobic decomposition of waste in the landfill. In this article it is presented the influence of aerobic pre-treatment of waste as well as leachate recirculation on susceptibility to biodegradation of waste in anaerobic laboratory reactors. The research has shown that in the reactor with aerobically treated waste stabilized with recilculation conversion of the organic carbon into the methane is about 45% higher than in the reactor with untreated waste stabilized without recirculation.

  4. Exploration of biodegradation mechanisms of black carbon-bound nonylphenol in black carbon-amended sediment

    International Nuclear Information System (INIS)

    Cheng, Guanghuan; Sun, Mingyang; Ge, Xinlei; Xu, Xinhua; Lin, Qi; Lou, Liping

    2017-01-01

    The present study aimed to investigate biodegradation mechanisms of black carbon (BC)-bound contaminants in BC-amended sediment when BC was applied to control organic pollution. The single-point Tenax desorption technique was applied to track the species changes of nonylphenol (NP) during biodegradation process in the rice straw carbon (RC)-amended sediment. And the correlation between the biodegradation and desorption of NP was analyzed. Results showed that microorganisms firstly degraded the rapid-desorbing NP (6 h Tenax desorption) in RC-amended sediment. The biodegradation facilitated the desorption of slow-desorbing NP, which was subsequently degraded as well (192 h Tenax desorption). Notably, the final amount of NP degradation was greater than that of NP desorption, indicating that absorbed NP by RC amendment can be degraded by microorganisms. Finally, the residual NP amount in RC-amended sediment was decided by RC content and its physicochemical property. Moreover, the presence of the biofilm was observed by the confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) so that microorganisms were able to overcome the mass transfer resistance and directly utilized the absorbed NP. Therefore, single-point Tenax desorption alone may not be an adequate basis for the prediction of the bioaccessibility of contaminants to microorganisms or bioremediation potential in BC-amended sediment. - Highlights: • Biodegradation mechanism of RC-bound NP in sediment was examined. • The microbe prioritized the degradation of NP in desorption fraction. • The microbe formed the biofilm to directly degrade part of non-desorbable NP. • Residual NP amount was decided by RC content and physicochemical property. • Quantifying biodegradation by bioavailability will underestimate the actual outcomes. - The microbes directly degrade the non-desorbable NP bound to amended RC, so quantifying the biodegradation only by desorption will underestimate the

  5. Stimulation of Diesel Fuel Biodegradation by Indigenous Nitrogen Fixing Bacterial Consortia.

    Science.gov (United States)

    Piehler; Swistak; Pinckney; Paerl

    1999-07-01

    > Abstract Successful stimulation of N2 fixation and petroleum hydrocarbon degradation in indigenous microbial consortia may decrease exogenous N requirements and reduce environmental impacts of bioremediation following petroleum pollution. This study explored the biodegradation of petroleum pollution by indigenous N2 fixing marine microbial consortia. Particulate organic carbon (POC) in the form of ground, sterile corn-slash (post-harvest leaves and stems) was added to diesel fuel amended coastal water samples to stimulate biodegradation of petroleum hydrocarbons by native microorganisms capable of supplying a portion of their own N. It was hypothesized that addition of POC to petroleum amended water samples from N-limited coastal waters would promote the growth of N2 fixing consortia and enhance biodegradation of petroleum. Manipulative experiments were conducted using samples from coastal waters (marinas and less polluted control site) to determine the effects of POC amendment on biodegradation of petroleum pollution by native microbial consortia. Structure and function of the microbial consortia were determined by measurement of N2 fixation (acetylene reduction), hydrocarbon biodegradation (14C hexadecane mineralization), bacterial biomass (AODC), number of hydrocarbon degrading bacteria (MPN), and bacterial productivity (3H-thymidine incorporation). Throughout this study there was a consistent enhancement of petroleum hydrocarbon degradation in response to the addition of POC. Stimulation of diesel fuel biodegradation following the addition of POC was likely attributable to increases in bacterial N2 fixation, diesel fuel bioavailability, bacterial biomass, and metabolic activity. Toxicity of the bulk phase water did not appear to be a factor affecting biodegradation of diesel fuel following POC addition. These results indicate that the addition of POC to diesel-fuel-polluted systems stimulated indigenous N2 fixing microbial consortia to degrade petroleum

  6. 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.

  7. 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.

  8. 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.

  9. Recent advances in glyphosate biodegradation.

    Science.gov (United States)

    Zhan, Hui; Feng, Yanmei; Fan, Xinghui; Chen, Shaohua

    2018-06-01

    Glyphosate has emerged as the most widespread herbicide to control annual and perennial weeds. Massive use of glyphosate for decades has resulted in its ubiquitous presence in the environment, and poses a threat to humans and ecosystem. Different approaches such as adsorption, photocatalytic degradation, and microbial degradation have been studied to break down glyphosate in the environment. Among these, microbial degradation is the most effective and eco-friendly method. During its degradation, various microorganisms can use glyphosate as a sole source of phosphorus, carbon, and nitrogen. Major glyphosate degradation pathways and its metabolites have been frequently investigated, but the related enzymes and genes have been rarely studied. There are many reviews about the toxicity and fate of glyphosate and its major metabolite, aminomethylphosphonic acid. However, there is lack of reviews on biodegradation and bioremediation of glyphosate. The aims of this review are to summarize the microbial degradation of glyphosate and discuss the potential of glyphosate-degrading microorganisms to bioremediate glyphosate-contaminated environments. This review will provide an instructive direction to apply glyphosate-degrading microorganisms in the environment for bioremediation.

  10. Syntrophic biodegradation of hydrocarbon contaminants.

    Science.gov (United States)

    Gieg, Lisa M; Fowler, S Jane; Berdugo-Clavijo, Carolina

    2014-06-01

    Anaerobic environments are crucial to global carbon cycling wherein the microbial metabolism of organic matter occurs under a variety of redox conditions. In many anaerobic ecosystems, syntrophy plays a key role wherein microbial species must cooperate, essentially as a single catalytic unit, to metabolize substrates in a mutually beneficial manner. Hydrocarbon-contaminated environments such as groundwater aquifers are typically anaerobic, and often methanogenic. Syntrophic processes are needed to biodegrade hydrocarbons to methane, and recent studies suggest that syntrophic hydrocarbon metabolism can also occur in the presence of electron acceptors. The elucidation of key features of syntrophic processes in defined co-cultures has benefited greatly from advances in 'omics' based tools. Such tools, along with approaches like stable isotope probing, are now being used to monitor carbon flow within an increasing number of hydrocarbon-degrading consortia to pinpoint the key microbial players involved in the degradative pathways. The metagenomic sequencing of hydrocarbon-utilizing consortia should help to further identify key syntrophic features and define microbial interactions in these complex communities. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. The effect of humic acids on biodegradation of polycyclic aromatic hydrocarbons depends on the exposure regime

    International Nuclear Information System (INIS)

    Tejeda-Agredano, Maria-Carmen; Mayer, Philipp; Ortega-Calvo, Jose-Julio

    2014-01-01

    Binding of polycyclic aromatic hydrocarbons (PAHs) to dissolved organic matter (DOM) can reduce the freely dissolved concentration, increase apparent solubility or enhance diffusive mass transfer. To study the effects of DOM on biodegradation, we used phenanthrene and pyrene as model PAHs, soil humic acids as model DOM and a soil Mycobacterium strain as a representative degrader organism. Humic acids enhanced the biodegradation of pyrene when present as solid crystals but not when initially dissolved or provided by partitioning from a polymer. Synchronous fluorescence spectrophotometry, scintillation counting and a microscale diffusion technique were applied in order to determine the kinetics of dissolution and diffusive mass transfer of pyrene. We suggest that humic acids can enhance or inhibit biodegradation as a result of the balance of two opposite effects, namely, solubilization of the chemicals on the one hand and inhibition of cell adhesion to the pollutant source on the other. Highlights: • Humic acids can enhance the biodegradation of PAHs. • The enhancement depends on how the bacteria are exposed to PAHs. • Humic acids stimulate if PAHs are provided by dissolution form crystals. • An inhibition occurs if PAHs are provided by partitioning from a silicone. • The balance between enhanced dissolution and decreased adhesion is the cause. -- Humic acids cause opposite effects on biodegradation of PAHs depending on the exposure regime

  12. 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

  13. 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

  14. 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.

  15. Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

    Energy Technology Data Exchange (ETDEWEB)

    McCarty, P. L.; Spormann, Alfred M.; Criddle, Craig, S.

    2003-12-11

    Chlorinated solvents are among the most widespread groundwater contaminants in the country, contamination which is also among the most difficult and expensive for remediation. These solvents are biodegradable in the absence of oxygen, but this biodegradation requires both a food source for the organisms (electron donor) and the presence of chlorinated solvent biodegrading organisms. These two requirements are present naturally at some contamination sites, leading to natural attenuation of the solvents. If one or both requirements are absent, then engineered bioremediation either through addition of an external electron donor or through bioaugmentation with appropriate microorganisms, or both, may be used for site remediation. The most difficult case for cleanup is when a large residual of undissolved chlorinated solvents are present, residing as dense -non-aqueous-phase- liquid ( DNAPL). A major focus of this study was on the potential for biodegradation of the solvents when pre sent as DNAPL where concentrations are very high and potential for toxicity to microorganisms exist. Another focus was on a better understanding of the biological mechanisms involved in chlorinated solvent biodegradation . These studies were directed towards the chlorinated solvents, trichloroethene (TCE), tetrachloroethene or perchloroethene (PCE), and carbon tetrachloride (CT). The potential for biodegradation of TCE and PCE DNAPL was clearly demonstrated in this research. From column soil studies and batch studies we found there to be a clear advantage in focusing efforts at bioremediation near the DNAPL. Here, chlorinated solvent concentrations are the highest, both because of more favorable reaction kinetics and because such high solvent concentrations are toxic to microorganisms, such as methanogens, which compete with dehalogenators for the electron donor. Additionally, biodegradation near a PCE DNAPL results in an enhanced dissolution rate for the chlorinated solvent, by factors of

  16. Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

    International Nuclear Information System (INIS)

    McCarty, P. L.; Spormann, Alfred M.; Criddle, Craig S.

    2003-01-01

    Chlorinated solvents are among the most widespread groundwater contaminants in the country, contamination which is also among the most difficult and expensive for remediation. These solvents are biodegradable in the absence of oxygen, but this biodegradation requires both a food source for the organisms (electron donor) and the presence of chlorinated solvent biodegrading organisms. These two requirements are present naturally at some contamination sites, leading to natural attenuation of the solvents. If one or both requirements are absent, then engineered bioremediation either through addition of an external electron donor or through bioaugmentation with appropriate microorganisms, or both, may be used for site remediation. The most difficult case for cleanup is when a large residual of undissolved chlorinated solvents are present, residing as dense -non-aqueous-phase- liquid ( DNAPL). A major focus of this study was on the potential for biodegradation of the solvents when pre sent as DNAPL where concentrations are very high and potential for toxicity to microorganisms exist. Another focus was on a better understanding of the biological mechanisms involved in chlorinated solvent biodegradation . These studies were directed towards the chlorinated solvents, trichloroethene (TCE), tetrachloroethene or perchloroethene (PCE), and carbon tetrachloride (CT). The potential for biodegradation of TCE and PCE DNAPL was clearly demonstrated in this research. From column soil studies and batch studies we found there to be a clear advantage in focusing efforts at bioremediation near the DNAPL. Here, chlorinated solvent concentrations are the highest, both because of more favorable reaction kinetics and because such high solvent concentrations are toxic to microorganisms, such as methanogens, which compete with dehalogenators for the electron donor. Additionally, biodegradation near a PCE DNAPL results in an enhanced dissolution rate for the chlorinated solvent, by factors of

  17. Elucidating the impact of micro-scale heterogeneous bacterial distribution on biodegradation

    Science.gov (United States)

    Schmidt, Susanne I.; Kreft, Jan-Ulrich; Mackay, Rae; Picioreanu, Cristian; Thullner, Martin

    2018-06-01

    Groundwater microorganisms hardly ever cover the solid matrix uniformly-instead they form micro-scale colonies. To which extent such colony formation limits the bioavailability and biodegradation of a substrate is poorly understood. We used a high-resolution numerical model of a single pore channel inhabited by bacterial colonies to simulate the transport and biodegradation of organic substrates. These high-resolution 2D simulation results were compared to 1D simulations that were based on effective rate laws for bioavailability-limited biodegradation. We (i) quantified the observed bioavailability limitations and (ii) evaluated the applicability of previously established effective rate concepts if microorganisms are heterogeneously distributed. Effective bioavailability reductions of up to more than one order of magnitude were observed, showing that the micro-scale aggregation of bacterial cells into colonies can severely restrict the bioavailability of a substrate and reduce in situ degradation rates. Effective rate laws proved applicable for upscaling when using the introduced effective colony sizes.

  18. Biodegradable behaviors of AZ31 magnesium alloy in simulated body fluid

    International Nuclear Information System (INIS)

    Song Yingwei; Shan Dayong; Chen Rongshi; Zhang Fan; Han Enhou

    2009-01-01

    Magnesium alloys have unique advantages to act as biodegradable implants for clinical application. The biodegradable behaviors of AZ31 in simulated body fluid (SBF) for various immersion time intervals were investigated by electrochemical impedance spectroscopy (EIS) tests and scanning electron microscope (SEM) observation, and then the biodegradable mechanisms were discussed. It was found that a protective film layer was formed on the surface of AZ31 in SBF. With increasing of immersion time, the film layer became more compact. If the immersion time was more than 24 h, the film layer began to degenerate and emerge corrosion pits. In the meantime, there was hydroxyapatite particles deposited on the film layer. The hydroxyapatite is the essential component of human bone, which indicates the perfect biocompatibility of AZ31 magnesium alloy.

  19. Synthesis of a novel biodegradable and electroactive polyphosphazene for biomedical application

    International Nuclear Information System (INIS)

    Zhang Qingsong; Yan Yuhua; Li Shipu; Feng Tao

    2009-01-01

    To prepare one electroactive and biodegradable biomaterial for biomedical application, a new synthetic strategy was developed to synthesize a novel electrically conductive biodegradable polyphosphazene polymer containing parent aniline pentamer (PAP) and glycine ethyl ester (GEE) as side chains by a nucleophilic substitution reaction. The electrical conductivity of the polymer is ∼2 x 10 -5 S cm -1 in the semiconducting region upon preliminarily protonic-doped experiment. The degradation and RSC96 Schwann cells experiments in vitro prove that the polymer is biodegradable and beneficial to the cell adhesion and proliferation. The as-synthesized polymer also shows good solubility in common organic solvent and good film-forming properties. This new type of polymer has potential applications as scaffolds for neuronal and cardiovascular tissue engineering or other biomedical devices that require electroactivity.

  20. Biodegradable polymeric foam with food waste; Shokumotsu zansa wo mochiita seibunkai kobunshi hahhotai

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, Kenji; Matsuyama, Kiyoshi; Yamauchi, Satoru; Takarabe, Shin' ichi

    1999-09-01

    A huge amount of food waste such as tea and beer dregs becomes a serious problem because of the lack of industrial waste space in Japan. On the other hand, the new polymeric foam is expected to be developed since the dangerous pollution of endorphin disrupters from industrial polymer foam is pointed out. In this work, we try to develop the biodegradable polymeric foam using the tea and beer dregs as secondary resources. And we examined the degradability of biodegradable polymer in the hydrothermal water for fundamental knowledge of polymeric foam production. We used an extruder equipped with a high pressure device to make the polymeric foam. And we examined the effect of the component ratio on the foam properties, foaming rate, strength, shrinkage rate, water-resistant. As a result, it was found that the amount of polymer is effective of quality of form and the biodegradability can be controlled by the amount of water and temperature. (author)

  1. 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.

  2. Biodegradable plastic bags on the seafloor: A future threat for seagrass meadows?

    Science.gov (United States)

    Balestri, Elena; Menicagli, Virginia; Vallerini, Flavia; Lardicci, Claudio

    2017-12-15

    Marine plastic litter is a global concern. Carrier bags manufactured from non-biodegradable polymers constitute a large component of this litter. Because of their adverse impact on marine life, non-biodegradable bags have recently been replaced by biodegradable ones. However, growing evidence shows that these latter are not readily degradable in marine sediments and can alter benthic assemblages. The potential impact of biodegradable bags on seagrasses inhabiting sandy bottoms, which are the most widespread and productive ecosystems of the coastal zones, has been ignored. Mesocosm experiments were conducted to assess the effect of a commercialized biodegradable bag on a common seagrass species of the Mediterranean, Cymodocea nodosa, both at the level of individual plant (clonal growth) and of plant community (plant-plant relationships), under three culture regimes (plant alone, in combination with a neighbour of the same species or of the co-existing seagrass Zostera noltei) simulating different natural conditions (bare substrate, monospecific meadows or mixed meadows). The bag behaviour in marine sediment and sediment physical/chemical variables were also examined. After six months of sediment exposure, the bag retained considerable mass (85% initial weight) and reduced sediment pore-water oxygen concentration and pH. In the presence of bag, C. nodosa root spread and vegetative recruitment increased compared to controls, both intra- and interspecific interactions shifted from neutral to competitive, and the growth form changed from guerrilla (loosely arranged group of widely spaced ramets) to phalanx form (compact structure of closed spaced ramets) but only with Z. noltei. These findings suggest that biodegradable bags altering sediment geochemistry could promote the spatial segregation of seagrass clones and influence species coexistence. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. 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

  4. A biodegradable vascularizing membrane: a feasibility study.

    Science.gov (United States)

    Kaushiva, Anchal; Turzhitsky, Vladimir M; Darmoc, Marissa; Backman, Vadim; Ameer, Guillermo A

    2007-09-01

    Regenerative medicine and in vivo biosensor applications require the formation of mature vascular networks for long-term success. This study investigated whether biodegradable porous membranes could induce the formation of a vascularized fibrous capsule and, if so, the effect of degradation kinetics on neovascularization. Poly(l-lactic acid) (PLLA) and poly(dl-lactic-co-glycolic) acid (PLGA) membranes were created by a solvent casting/salt leaching method. Specifically, PLLA, PLGA 75:25 and PLGA 50:50 polymers were used to vary degradation kinetics. The membranes were designed to have an average 60mum pore diameter, as this pore size has been shown to be optimal for inducing blood vessel formation around nondegradable polymer materials. Membrane samples were imaged by scanning electron microscopy at several time points during in vitro degradation to assess any changes in pore structure. The in vivo performance of the membranes was assessed in Sprague-Dawley rats by measuring vascularization within the fibrous capsule that forms adjacent to implants. The vascular density within 100microm of the membranes was compared with that seen in normal tissue, and to that surrounding the commercially available vascularizing membrane TheraCyte. The hemoglobin content of tissue containing the membranes was measured by four-dimensional elastic light scattering as a novel method to assess tissue perfusion. Results from this study show that slow-degrading membranes induce greater amounts of neovascularization and a thinner fibrous capsule relative to fast degrading membranes. These results may be due both to an initially increased number of macrophages surrounding the slower degrading membranes and to the maintenance of their initial pore structure.

  5. 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.

  6. 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)

  7. Biodegradable nanoparticles for gene therapy technology

    International Nuclear Information System (INIS)

    Hosseinkhani, Hossein; He, Wen-Jie; Chiang, Chiao-Hsi; Hong, Po-Da; Yu, Dah-Shyong; Domb, Abraham J.; Ou, Keng-Liang

    2013-01-01

    Rapid propagations in materials technology together with biology have initiated great hopes in the possibility of treating many diseases by gene therapy technology. Viral and non-viral gene carriers are currently applied for gene delivery. Non-viral technology is safe and effective for the delivery of genetic materials to cells and tissues. Non-viral systems are based on plasmid expression containing a gene encoding a therapeutic protein and synthetic biodegradable nanoparticles as a safe carrier of gene. Biodegradable nanoparticles have shown great interest in drug and gene delivery systems as they are easy to be synthesized and have no side effect in cells and tissues. This review provides a critical view of applications of biodegradable nanoparticles on gene therapy technology to enhance the localization of in vitro and in vivo and improve the function of administered genes

  8. 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.

  9. Biodegradable Polymers and Stem Cells for Bioprinting

    Directory of Open Access Journals (Sweden)

    Meijuan Lei

    2016-04-01

    Full Text Available It is imperative to develop organ manufacturing technologies based on the high organ failure mortality and serious donor shortage problems. As an emerging and promising technology, bioprinting has attracted more and more attention with its super precision, easy reproduction, fast manipulation and advantages in many hot research areas, such as tissue engineering, organ manufacturing, and drug screening. Basically, bioprinting technology consists of inkjet bioprinting, laser-based bioprinting and extrusion-based bioprinting techniques. Biodegradable polymers and stem cells are common printing inks. In the printed constructs, biodegradable polymers are usually used as support scaffolds, while stem cells can be engaged to differentiate into different cell/tissue types. The integration of biodegradable polymers and stem cells with the bioprinting techniques has provided huge opportunities for modern science and technologies, including tissue repair, organ transplantation and energy metabolism.

  10. Biodegradable Polymers and Stem Cells for Bioprinting.

    Science.gov (United States)

    Lei, Meijuan; Wang, Xiaohong

    2016-04-29

    It is imperative to develop organ manufacturing technologies based on the high organ failure mortality and serious donor shortage problems. As an emerging and promising technology, bioprinting has attracted more and more attention with its super precision, easy reproduction, fast manipulation and advantages in many hot research areas, such as tissue engineering, organ manufacturing, and drug screening. Basically, bioprinting technology consists of inkjet bioprinting, laser-based bioprinting and extrusion-based bioprinting techniques. Biodegradable polymers and stem cells are common printing inks. In the printed constructs, biodegradable polymers are usually used as support scaffolds, while stem cells can be engaged to differentiate into different cell/tissue types. The integration of biodegradable polymers and stem cells with the bioprinting techniques has provided huge opportunities for modern science and technologies, including tissue repair, organ transplantation and energy metabolism.

  11. 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.

  12. 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.)

  13. 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.

  14. 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...

  15. 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...

  16. 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)

  17. 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

  18. Development of Biomarkers for Assessing In Situ RDX Biodegradation Potential

    Science.gov (United States)

    2016-06-10

    the RDX degrading communities in four different soil slurries. The third task examined the microorganisms involved in RDX biodegradation from...RDX biodegradation at two Navy sites. Several key microorganisms were associated with RDX removal in these mixed communities. These phylogenetic and...manuscripts. 1 ABSTRACT Objective The objective was to identify the microorganisms and genes responsible for the biodegradation of RDX (hexahydro

  19. Mass transfer analysis for terephthalic acid biodegradation by ...

    African Journals Online (AJOL)

    Biodegradation of terephthalic acid (TA) by polyvinyl alcohol (PVA)-alginate immobilized Pseudomonas sp. was carried out in a packed-bed reactor. The effect of inlet TA concentration on biodegradation was investigated at 30°C, pH 7 and flow rate of 20 ml/min. The effects of flow rate on mass transfer and biodegradation ...

  20. 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...

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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.

  6. 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".

  7. Biodegradation of norfloxacin by Penicillium frequentans isolated ...

    African Journals Online (AJOL)

    One norfloxacin-degrading fungi was isolated from soil contaminated by norfloxacin and preliminary identified as Penicillium frequentans. Indoor simulative degradation experiments were carried out to investigate the biodegradation kinetics of norfloxacin with or without NFX3 in soil. The results indicate that the ...

  8. Fabrication of Environmentally Biodegradable Lignin Nanoparticles

    NARCIS (Netherlands)

    Frangville, C.; Rutkevicius, M.; Richter, A.P.; Velev, O.D.; Stoyanov, S.D.; Paunov, V.N.

    2012-01-01

    We developed a method for the fabrication of novel biodegradable nanoparticles (NPs) from lignin which are apparently non-toxic for microalgae and yeast. We compare two alternative methods for the synthesis of lignin NPs which result in particles of very different stability upon change of pH. The

  9. Cyclodextrin-enhanced biodegradation of phenanthrene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.-M.; Marlowe, E.M.; Miller-Maier, R.M.; Brusseau, M.L. [University of Arizona, Tuscon, AZ (United States). Dept. of Soil, Water and Environmental Science

    1998-07-01

    The effectiveness of in situ bioremediation in many systems may be constrained by low contaminant bioavailability due to limited aqueous solubility or a large magnitude of sorption. The objective of this research was to evaluate the effect of hydroxypropyl-{beta}-cyclodextrin (HPCD) on phenanthrene solubilization and biodegradation. Results showed that analytical-grade HPCD can significantly increase the apparent solubility of phenanthrene. The increase in apparent solubility had a major impact on the biodegradation rate of phenanthrene. For example, in the presence of 10{sup 5} mg L{sup -1} HPCD, the substrate utilization rate increased from 0.17 mg h{sup -1} to 0.93 mg h{sup -1} while the apparent solubility was increased from 1.3 mg L{sup -1} to 161.3 mg L{sup -1}. As a result, only 0.3% of the phenanthrene remained at the end of a 48 h incubation for the highest concentration of HPCD tested (10{sup 5} mg L{sup -1}). In contrast, 45.2% of the phenanthrene remained in the absence of HPCD. Technical-grade HPCD, which contains the biodegradable impurity propylene glycol, also increased the substrate utilization rate, although to a lesser extent than the analytical-grade HPCD. On the basis of these results, it appears that HPCD can significantly increase the bioavailability, and thereby enhance the biodegradation of phenanthrene. 26 refs., 5 figs.

  10. Formulation and characterization of caffeine biodegradable chewing ...

    African Journals Online (AJOL)

    chewing gum delivery system for alertness using ... texture profile analysis (TPA), and also evaluated for biodegradation, microstructure`, in vitro .... human chewing. .... Data are presented as mean ± standard error mean (n=6) .... No conflict of interest associated with this work. ... d), which permit unrestricted use, distribution,.

  11. Biodegradation of chlorobenzoic acids by ligninolytic fungi

    Czech Academy of Sciences Publication Activity Database

    Muzikář, Milan; Křesinová, Zdena; Svobodová, Kateřina; Filipová, Alena; Čvančarová, Monika; Cajthamlová, Kamila; Cajthaml, Tomáš

    2011-01-01

    Roč. 196, - (2011), s. 386-394 ISSN 0304-3894 R&D Projects: GA MŠk 2B06156; GA ČR GA525/09/1058 Institutional research plan: CEZ:AV0Z50200510 Keywords : Chlorobenzoic acid * Polychlorinated biphenyls * Biodegradation Subject RIV: EE - Microbiology, Virology Impact factor: 4.173, year: 2011

  12. 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.

  13. 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

  14. Preparation of Natural and Synthetic Porous Biodegradable ...

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Preparation of Natural and Synthetic Porous Biodegradable Scaffolds for Infected Wounds. Characterised for their physical properties, pore size and release kinetics. Release kinetics of bioactive molecules (antibiotics) in a controlled fashion. Release pattern of the ...

  15. Biodegradable Shape Memory Polymers in Medicine.

    Science.gov (United States)

    Peterson, Gregory I; Dobrynin, Andrey V; Becker, Matthew L

    2017-11-01

    Shape memory materials have emerged as an important class of materials in medicine due to their ability to change shape in response to a specific stimulus, enabling the simplification of medical procedures, use of minimally invasive techniques, and access to new treatment modalities. Shape memory polymers, in particular, are well suited for such applications given their excellent shape memory performance, tunable materials properties, minimal toxicity, and potential for biodegradation and resorption. This review provides an overview of biodegradable shape memory polymers that have been used in medical applications. The majority of biodegradable shape memory polymers are based on thermally responsive polyesters or polymers that contain hydrolyzable ester linkages. These materials have been targeted for use in applications pertaining to embolization, drug delivery, stents, tissue engineering, and wound closure. The development of biodegradable shape memory polymers with unique properties or responsiveness to novel stimuli has the potential to facilitate the optimization and development of new medical applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Evaluation of biodegradation and biocompatibility of collagen ...

    Indian Academy of Sciences (India)

    ever, its fast biodegradation and low mechanical strength are the foremost issues .... containing 250 ml of simulated body fluids (SBFs) with ion concentrations ( ..... [6] Kong M, Chen X G, Xing K and Park H J 2010 Int. J. Food. Microbiol. 144 51.

  17. Biodegradation of synthetic detergents in wastewater

    African Journals Online (AJOL)

    STORAGESEVER

    2009-03-20

    Mar 20, 2009 ... carrier gas at 37 psi. Hydrogen and air flow rates were 9 and 13 psi ... 24 h, by filtering the content of each set of test tubes using sterile filter paper while ..... environment-friendly, since it is biodegradable and it would enhance ...

  18. Biodegradable polymersomes for targeted ultrasound imaging

    NARCIS (Netherlands)

    Zhou, W.; Hennink, W.E.; Feijen, J.; Meng, Fenghua; Sam, T; Engbers, G.H.M.; Feijen, Jan

    2006-01-01

    Biodegradable polymersomes with a sub-micron size were prepared by using poly(ethylene glycol)–polylactide (PEG–PDLLA) block-copolymers in aqueous media. Air-encapsulated polymersomes could be obtained by a lyophilization/rehydration procedure. Preliminary results showed that these polymersomes were

  19. Polyvinyl alcohol biodegradation under denitrifying conditions

    Czech Academy of Sciences Publication Activity Database

    Marušincová, H.; Husárová, L.; Růžička, J.; Ingr, M.; Navrátil, Václav; Buňková, L.; Koutný, M.

    2013-01-01

    Roč. 84, October (2013), s. 21-28 ISSN 0964-8305 Grant - others:GA ČR(CZ) GAP108/10/0200 Institutional support: RVO:61388963 Keywords : polyvinyl alcohol * biodegradation * denitrification * waste-water treatment * anaerobic * Steroidobacter Subject RIV: EI - Biotechnology ; Bionics Impact factor: 2.235, year: 2013

  20. Biodegradable elastomeric scaffolds for soft tissue engineering

    NARCIS (Netherlands)

    Pêgo, A.P.; Poot, Andreas A.; Grijpma, Dirk W.; Feijen, Jan

    2003-01-01

    Elastomeric copolymers of 1,3-trimethylene carbonate (TMC) and ε-caprolactone (CL) and copolymers of TMC and D,L-lactide (DLLA) have been evaluated as candidate materials for the preparation of biodegradable scaffolds for soft tissue engineering. TMC-DLLA copolymers are amorphous and degrade more

  1. 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.

  2. (Biodegradable Ionomeric Polyurethanes Based on Xanthan: Synthesis, Properties, and Structure

    Directory of Open Access Journals (Sweden)

    T. V. Travinskaya

    2017-01-01

    Full Text Available New (biodegradable environmentally friendly film-forming ionomeric polyurethanes (IPU based on renewable biotechnological polysaccharide xanthan (Xa have been obtained. The influence of the component composition on the colloidal-chemical and physic-mechanical properties of IPU/Xa and based films, as well as the change of their properties under the influence of environmental factors, have been studied. The results of IR-, PMS-, DMA-, and X-ray scattering study indicate that incorporation of Xa into the polyurethane chain initiates the formation of a new polymer structure different from the structure of the pure IPU (matrix: an amorphous polymer-polymer microdomain has occurred as a result of the chemical interaction of Xa and IPU. It predetermines the degradation of the IPU/Xa films as a whole, unlike the mixed polymer systems, and plays a key role in the improvement of material performance. The results of acid, alkaline hydrolysis, and incubation into the soil indicate the increase of the intensity of degradation processes occurring in the IPU/Xa in comparison with the pure IPU. It has been shown that the introduction of Xa not only imparts the biodegradability property to polyurethane, but also improves the mechanical properties.

  3. Biodegradable electroactive materials for tissue engineering applications

    Science.gov (United States)

    Guimard, Nathalie Kathryn

    This dissertation focuses on the development of biomaterials that could be used to enhance the regeneration of severed peripheral nerves. These materials were designed to be electroactive, biodegradable, and biocompatible. To render the materials electroactive the author chose to incorporate conducting polymer (CP) units into the materials. Because CPs are inherently non-degradable, the key challenge was to create a CP-based material that was also biodegradable. Two strategies were explored to generate a biodegradable CP-based material. The first strategy centered around the incorporation of both electroactive and biodegradable subunits into a copolymer system. In the context of this approach, two bis(methoxyquaterthiophene)-co-adipic acid polyester (QAPE) analogues were successfully synthesized, one through polycondensation (giving undoped QAPE) and the second through oxidative polymerization (giving doped QAPE-2). QAPE was found to be electroactive by cyclic voltammetry, bioerodible, and cytocompatible with Schwann cells. QAPE was doped with ferric perchlorate, although only a low doping percentage was realized (˜8%). Oxidative polymerization of a bis(bithiophene) adipate permitted the direct synthesis of doped QAPE-2, which was found to have a higher doping level (˜24%). The second strategy pursued with the goal of generating an electroactive biodegradable material involved covalently immobilizing low molecular weight polythiophene chains onto the surface of crosslinked hyaluronic acid (HA) films. HA films are not only biodegradable and biocompatible, but they also provide mechanical integrity to bilayer systems. Dicyclocarbodiimide coupling of carboxylic acids to HA alcohol groups was used to functionalize HA films. The HA-polythiophene composite is still in the early stages of development. However, to date, thiophene has been successfully immobilized at the surface of HA films with a high degree of substitution. The author has also shown that thiophene

  4. 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.

  5. 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

  6. 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

  7. Predicting ready biodegradability of premanufacture notice chemicals.

    Science.gov (United States)

    Boethling, Robert S; Lynch, David G; Thom, Gary C

    2003-04-01

    Chemical substances other than pesticides, drugs, and food additives are regulated by the U.S. Environmental Protection Agency (U.S. EPA) under the Toxic Substances Control Act (TSCA), but the United States does not require that new substances be tested automatically for such critical properties as biodegradability. The resulting lack of submitted data has fostered the development of estimation methods, and the BioWIN models for predicting biodegradability from chemical structure have played a prominent role in premanufacture notice (PMN) review. Until now, validation efforts have used only the Japanese Ministry of International Trade and Industry (MITI) test data and have not included all models. To assess BioWIN performance with PMN substances, we assembled a database of PMNs for which ready biodegradation data had been submitted over the period 1995 through 2001. The 305 PMN structures are highly varied and pose major challenges to chemical property estimation. Despite the variability of ready biodegradation tests, the use of at least six different test methods, and widely varying quality of submitted data, accuracy of four of six BioWIN models (MITI linear, MITI nonlinear, survey ultimate, survey primary) was in the 80+% range for predicting ready biodegradability. Greater accuracy (>90%) can be achieved by using model estimates only when the four models agree (true for 3/4 of the PMNs). The BioWIN linear and nonlinear probability models did not perform as well even when classification criteria were optimized. The results suggest that the MITI and survey BioWIN models are suitable for use in screening-level applications.

  8. 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)

  9. [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.

  10. 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

  11. Biodegradation of metal citrate complexes and implications for toxic-metal mobility

    International Nuclear Information System (INIS)

    Francis, A.J.; Dodge, C.J.; Gillow, J.B.

    1992-01-01

    The presence of synthetic and naturally occurring chelating agents in nuclear and toxic-metal wastes is a major concern because of their potential to enhance mobilization of metal ions away from the disposal sites. Of particular interest is citric acid, which is present in low-level and transuranic radioactive wastes and in domestic and industrial wastes (as washing fluids, for instance), as well as being found naturally. Citrate ions form multidentate, stable complexes with a variety of toxic metals and radionuclides; but biodegradation of these complexes, precipitating the metal ions as insoluble hydroxides, oxides or other salts, may retard migration. Here we report a study of the biodegradation of citrate complexes of Ca, Fe(II), Fe(III), Cd, Cu, Ni, Pb and U. Several of these complexes were not readily degraded by bacteria, and the biodegradability depended on the chemical nature of the complex, not on the toxicity of the metal to the bacteria. This resistance to biodegradation implies that citrate complexation may play an important part in migration of these hazardous wastes. (author)

  12. Biodegradation and ecotoxicity of soil contaminated by pentachlorophenol applying bioaugmentation and addition of sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Zuzana, S.; Katarina, D.; Livia, T. [Slovak Technical University Bratislava, Bratislava (Slovakia). Dept. of Biochemical Technology

    2009-02-15

    Biodegradation of pentachlorophenol (PCP) in soil by autochthonous microorganisms and in soil bioaugmented by the bacterial strain Comamonas testosteroni CCM 7530 was studied. Subsequent addition of organomineral complex (OMC) or lignite as possible sorbents for PCP immobilization has been investigated as well. The OMC was prepared from humic acids (HAs) isolated from lignite by binding them onto zeolite. Biodegradation of PCP and number of colony forming units (CFUs) were determined in the three types of soil, Chernozem, Fluvisol, and Regosol, freshly spiked with PCP and amended separately with tested sorbents. The enhancing effect of sorbent addition and bioaugmentation on PCP biodegradation depended mainly on the soil type and the initial PCP concentration. Microbial activity resulted in biotransformation of PCP into certain toxic substances, probably lower chlorinated phenols that are more soluble than PCP, and therefore more toxic to present biota. Therefore, it was necessary to monitor soil ecotoxicity during biodegradation. Addition of the OMC resulted in a more significant decrease of soil toxicity in comparison with addition of lignite. Lignite and OMC appear to be good traps for PCP with potential application in remediation technology.

  13. 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.

  14. Biodegradable plastics derived from micro-fibrillated cellulose fiber and chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Nishiyama, M.; Hosokawa, J.; Yoshihara, K.; Kubo, T.; Kabeya, H.; Endo, T. [Shikoku National Industrial Research Inst., Kagawa (Japan)

    1995-12-25

    We have been carrying out studies to develop biodegradable plastics from natural polysaccharides. We have found that a combination of micro-fibrillated cellulose fiber and chitosan produces a useful material that can be used to form biodegradable film and moldings. Cellulose-chitosan composite film demonstrate higher strength than general purpose plastic films, and wet strength peaks when chitosan content is 10-20%. The relatively small amount of chitosan needed is economically convenient because chitosan is more expensive than cellulose. This film biodegrade well in soil, completely dissolving and disappearing in two months. Biodegradability is influenced by the temperature used in thermal treatment the film, the quantity of acid groups in the cellulose, and other factors. These characteristics will be used to control decomposition. Since cellulose-chitosan-plastics are not thermoplastics, we have been working on joint research with companies to produce films, nonwoven fabrics and foams. We discuss here the properties and application of these composite moldings. 4 refs., 3 figs., 3 tabs.

  15. 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.

  16. Biodegradable Polyphosphazene-Based Blends for Regenerative Engineering.

    Science.gov (United States)

    Ogueri, Kenneth S; Escobar Ivirico, Jorge L; Nair, Lakshmi S; Allcock, Harry R; Laurencin, Cato T

    2017-03-01

    The occurrence of musculoskeletal tissue injury or disease and the subsequent functional impairment is at an alarming rate. It continues to be one of the most challenging problems in the human health care. Regenerative engineering offers a promising transdisciplinary strategy for tissues regeneration based on the convergence of tissue engineering, advanced materials science, stem cell science, developmental biology and clinical translation. Biomaterials are emerging as extracellular-mimicking matrices designed to provide instructive cues to control cell behavior and ultimately, be applied as therapies to regenerate damaged tissues. Biodegradable polymers constitute an attractive class of biomaterials for the development of scaffolds due to their flexibility in chemistry and the ability to be excreted or resorbed by the body. Herein, the focus will be on biodegradable polyphosphazene-based blend systems. The synthetic flexibility of polyphosphazene, combined with the unique inorganic backbone, has provided a springboard for more research and subsequent development of numerous novel materials that are capable of forming miscible blends with poly (lactide-co-glycolide) (PLAGA). Laurencin and co-workers has demonstrated the exploitation of the synthetic flexibility of Polyphosphazene that will allow the design of novel polymers, which can form miscible blends with PLAGA for biomedical applications. These novel blends, due to their well-tuned biodegradability, and mechanical and biological properties coupled with the buffering capacity of the degradation products, constitute ideal materials for regeneration of various musculoskeletal tissues. Regenerative engineering aims to regenerate complex tissues to address the clinical challenge of organ damage. Tissue engineering has largely focused on the restoration and repair of individual tissues and organs, but over the past 25 years, scientific, engineering, and medical advances have led to the introduction of this new

  17. Biodegradable Polyphosphazene-Based Blends for Regenerative Engineering

    Science.gov (United States)

    Ogueri, Kenneth S.; Escobar Ivirico, Jorge L.; Nair, Lakshmi S.; Allcock, Harry R.; Laurencin, Cato T.

    2017-01-01

    The occurrence of musculoskeletal tissue injury or disease and the subsequent functional impairment is at an alarming rate. It continues to be one of the most challenging problems in the human health care. Regenerative engineering offers a promising transdisciplinary strategy for tissues regeneration based on the convergence of tissue engineering, advanced materials science, stem cell science, developmental biology and clinical translation. Biomaterials are emerging as extracellular-mimicking matrices designed to provide instructive cues to control cell behavior and ultimately, be applied as therapies to regenerate damaged tissues. Biodegradable polymers constitute an attractive class of biomaterials for the development of scaffolds due to their flexibility in chemistry and the ability to be excreted or resorbed by the body. Herein, the focus will be on biodegradable polyphosphazene-based blend systems. The synthetic flexibility of polyphosphazene, combined with the unique inorganic backbone, has provided a springboard for more research and subsequent development of numerous novel materials that are capable of forming miscible blends with poly (lactide-co-glycolide) (PLAGA). Laurencin and co-workers has demonstrated the exploitation of the synthetic flexibility of Polyphosphazene that will allow the design of novel polymers, which can form miscible blends with PLAGA for biomedical applications. These novel blends, due to their well-tuned biodegradability, and mechanical and biological properties coupled with the buffering capacity of the degradation products, constitute ideal materials for regeneration of various musculoskeletal tissues. Lay Summary Regenerative engineering aims to regenerate complex tissues to address the clinical challenge of organ damage. Tissue engineering has largely focused on the restoration and repair of individual tissues and organs, but over the past 25 years, scientific, engineering, and medical advances have led to the introduction of

  18. Microbial production of four biodegradable siderophores under submerged fermentation.

    Science.gov (United States)

    Fazary, Ahmed E; Al-Shihri, Ayed S; Alfaifi, Mohammad Y; Saleh, Kamel A; Alshehri, Mohammed A; Elbehairi, Serag Eldin I; Ju, Yi-Hsu

    2016-07-01

    Four siderophore analogues were isolated and purified from Escherichia coli, Bacillus spp. ST13, and Streptomyces pilosus microorganisms under some specific submerged fermentation conditions. In order to evaluate the highest production of this siderophore analogues through the growth, a rapid spectrophotometric screening semi-quantitative method was used, in which interestingly the analogues were isolated in its own form not its iron chelate. After chromatographic separation, the chemical structures of the isolated and purified siderophores were illustrated using detailed spectroscopic techniques. The biodegradation studies were done on that four novel isolated and purified siderophores following OECD protocols. In addition, the bioactivities of these siderophores and their iron complexes were examined and evaluated. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Marine biofouling resistance of polyurethane with biodegradation and hydrolyzation.

    Science.gov (United States)

    Xu, Wentao; Ma, Chunfeng; Ma, Jielin; Gan, Tiansheng; Zhang, Guangzhao

    2014-03-26

    We have prepared polyurethane with poly(ε-caprolactone) (PCL) as the segments of the main chain and poly(triisopropylsilyl acrylate) (PTIPSA) as the side chains by a combination of radical polymerization and a condensation reaction. Quartz crystal microbalance with dissipation studies show that polyurethane can degrade in the presence of enzyme and the degradation rate decreases with the PTIPSA content. Our studies also demonstrate that polyurethane is able to hydrolyze in artificial seawater and the hydrolysis rate increases as the PTIPSA content increases. Moreover, hydrolysis leads to a hydrophilic surface that is favorable to reduction of the frictional drag under dynamic conditions. Marine field tests reveal that polyurethane has good antifouling ability because polyurethane with a biodegradable PCL main chain and hydrolyzable PTIPSA side chains can form a self-renewal surface. Polyurethane was also used to carry and release a relatively environmentally friendly antifoulant, and the combined system exhibits a much higher antifouling performance even in a static marine environment.

  20. Biodegradation of magnetic nanoparticles evaluated from Moessbauer and magnetization measurements

    Energy Technology Data Exchange (ETDEWEB)

    Mischenko, I., E-mail: IlyaMischenko@rambler.ru; Chuev, M. [Russian Academy of Sciences, Institute of Physics and Technology (Russian Federation); Cherepanov, V.; Polikarpov, M.; Panchenko, V. [National Research Centre ' Kurchatov Institute' (Russian Federation)

    2013-04-15

    In order to extract a quantitative information about characteristics of the magnetic nanoparticles injected into a living organism it is necessary to define a model of the magnetic dynamics for fitting self-consistently the whole set of the experimental data, specifically, the evolution of Moessbauer spectral shape with temperature and external magnetic field as well as the magnetization curves. We have developed such a model and performed such an analysis of the temperature- and magnetic field-dependent spectra and magnetization curves of nanoparticles injected into mice. This allowed us to reliably evaluate changes in the characteristics of the residual particles and their chemical transformation to paramagnetic ferritin-like forms in different mouse organs as a function of time. Actually, the approach makes it possible to quantitatively characterize biodegradation and biotransformation of magnetic nanoparticles delivered in a body.

  1. Biodegradation of crude oil in different types of marine sediment

    International Nuclear Information System (INIS)

    Hii, Y.S.; Law, A.T.

    1999-01-01

    An active oil-oxidizing bacterium, named Nap C was isolated from the sediment sample of Port Dickson coastal area for this study. Nap C is a gram negative, rod shape marine bacterium. It forms spore when the condition is not favorable. Three different types of treated marine sediment; sand, silt and clay were used in this study. The degradation of Malaysian Tapis A crude oil in the different types of marine sediment were assessed. Silt type of marine sediment was found to sustain highest biodegradation compared to clay type and sand type. 8.6.67% of the Malaysian Tapis A crude oil was degraded in silt type of marine sediment within 10 days of incubation. Where as there were only 60% and 73% of the Malaysian Tapis A crude oil was degraded in sand and clay type of marine sediment respectively. Microbial biomass estimation in the sediment was estimated by indirect phospholipid enumeration technique. (author)

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Modeling ready biodegradability of fragrance materials.

    Science.gov (United States)

    Ceriani, Lidia; Papa, Ester; Kovarich, Simona; Boethling, Robert; Gramatica, Paola

    2015-06-01

    In the present study, quantitative structure activity relationships were developed for predicting ready biodegradability of approximately 200 heterogeneous fragrance materials. Two classification methods, classification and regression tree (CART) and k-nearest neighbors (kNN), were applied to perform the modeling. The models were validated with multiple external prediction sets, and the structural applicability domain was verified by the leverage approach. The best models had good sensitivity (internal ≥80%; external ≥68%), specificity (internal ≥80%; external 73%), and overall accuracy (≥75%). Results from the comparison with BIOWIN global models, based on group contribution method, show that specific models developed in the present study perform better in prediction than BIOWIN6, in particular for the correct classification of not readily biodegradable fragrance materials. © 2015 SETAC.

  7. Nanoparticles from Degradation of Biodegradable Plastic Mulch

    Science.gov (United States)

    Flury, Markus; Sintim, Henry; Bary, Andy; English, Marie; Schaefer, Sean

    2017-04-01

    Plastic mulch films are commonly used in crop production. They provide multiple benefits, including control of weeds and insects, increase of soil and air temperature, reduction of evaporation, and prevention of soil erosion. The use of plastic mulch film in agriculture has great potential to increase food production and security. Plastic mulch films must be retrieved and disposed after usage. Biodegradable plastic mulch films, who can be tilled into the soil after usage offer great benefits as alternative to conventional polyethylene plastic. However, it has to be shown that the degradation of these mulches is complete and no micro- and nanoparticles are released during degradation. We conducted a field experiment with biodegradable mulches and tested mulch degradation. Mulch was removed from the field after the growing season and composted to facilitate degradation. We found that micro- and nanoparticles were released during degradation of the mulch films in compost. This raises concerns about degradation in soils as well.

  8. Biodegradation of polyurethane derived from castor oil

    Directory of Open Access Journals (Sweden)

    José M. Cangemi

    2008-09-01

    Full Text Available The aim of this research was to study the biodegradation of a polymer derived from castor oil, which is a renewable, natural material that is a practical alternative for the replacement of traditional polyurethane foams. Due to its molecular structure, which contains polyester segments derived from vegetable oil, the polymeric surface is susceptible to microorganism attack. This study tested the biological degrading agent that was in contact with the microorganisms resulting from microbiological grease degrading agents, when foam was inoculated. Solid-media agar-plate tests were conducted for their potential to evaluate the biodegradation of polymeric particles by specific strains of microorganisms during 216 hours. The growth rate was defined. This technique provides a way of distinguishing the degradation abilities of microorganisms from the degradability of materials.

  9. 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.

  10. 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.

  11. 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...

  12. 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.

  13. 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

  14. 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.

  15. Corexit 9500 Enhances Oil Biodegradation and Changes ...

    Science.gov (United States)

    While COREXIT 9500 is widely applied after oil spills for its reported dispersing activity, there is still a debate on the effectiveness on enhancing oil biodegradation and its potential toxic effect on microbial communities. To better understand the impact of COREXIT 9500 on the structure and activity levels of hydrocarbon degrading microbial communities, we analyzed next-generation 16S rRNA gene sequencing libraries of hydrocarbon enrichments grown at cryophilic and mesophilic conditions and using both DNA and RNA extracts as sequencing templates. Oil biodegradation patterns in both cryophilic and mesophilic enrichments were consistent with those reported in the literature (i.e., aliphatics were degraded faster than aromatics). A slight increase in biodegradation was observed in the presence of COREXIT at both 25°C and 5°C experiments. Differences in community structure were observed between treatment conditions in the DNA-based libraries. The 25°C consortia was dominated by unclassified members of the Vibrio, Pseudoidiomarina, Marinobacter, Alcanivorax, and Thallassospira species, while the 5°C consortia were dominated by several genera of Flavobacteria, Alcanivorax and Oleispira. With the exception of Vibrio-like species, members of these genera have been linked to hydrocarbon degradation and have been observed after oil spills. Colwellia and Cycloclasticus, known aromatic degraders, was also found in these enrichments. RNA-based sequencing of 25°C

  16. 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

  17. 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)

  18. 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

  19. Biodegradable materials as binders for IVth generation moulding sands

    OpenAIRE

    K. Major-Gabry

    2015-01-01

    This paper focuses on the possibility of using the biodegradable materials as binders (or parts of binders?compositions) for foundry moulding and core sands. Results showed that there is a great possibility of using available biodegradable materials as foundry moulding sand binders. Using biodegradable materials as partial content of new binders, or additives to moulding sands may not only decrease the toxicity and increase reclamation ability of tested moulding sands, but also accelerate the...

  20. "Rational" management of dichlorophenols biodegradation by the microalga Scenedesmus obliquus.

    Science.gov (United States)

    Papazi, Aikaterini; Kotzabasis, Kiriakos

    2013-01-01

    The microalga Scenedesmus obliquus exhibited the ability to biodegrade dichlorophenols (dcps) under specific autotrophic and mixotrophic conditions. According to their biodegradability, the dichlorophenols used can be separated into three distinct groups. Group I (2,4-dcp and 2,6 dcp - no meta-substitution) consisted of quite easily degraded dichlorophenols, since both chloride substituents are in less energetically demanding positions. Group II (2,3-dcp, 2,5-dcp and 3,4-dcp - one meta-chloride) was less susceptible to biodegradation, since one of the two substituents, the meta one, required higher energy for C-Cl-bond cleavage. Group III (3,5-dcp - two meta-chlorides) could not be biodegraded, since both chlorides possessed the most energy demanding positions. In general, when the dcp-toxicity exceeded a certain threshold, the microalga increased the energy offered for biodegradation and decreased the energy invested for biomass production. As a result, the biodegradation per cell volume of group II (higher toxicity) was higher, than group I (lower toxicity) and the biodegradation of dichlorophenols (higher toxicity) was higher than the corresponding monochlorophenols (lower toxicity). The participation of the photosynthetic apparatus and the respiratory mechanism of microalga to biodegrade the group I and the group II, highlighted different bioenergetic strategies for optimal management of the balance between dcp-toxicity, dcp-biodegradability and culture growth. Additionally, we took into consideration the possibility that the intermediates of each dcp-biodegradation pathway could influence differently the whole biodegradation procedures. For this reason, we tested all possible combinations of phenolic intermediates to check cometabolic interactions. The present contribution bring out the possibility of microalgae to operate as "smart" bioenergetic "machines", that have the ability to continuously "calculate" the energy reserves and "use" the most energetically

  1. Biodegradable magnesium-alloy stent:current situation in research

    International Nuclear Information System (INIS)

    Chen Hua; Zhao Xianxian

    2011-01-01

    In recent years, permanent metal stents are employed in the majority of interventional therapies; nevertheless, such kind of stents carries the problems of thrombosis and restenosis. Therefore, the biodegradable magnesium alloy stent has become the focus of attention. Theoretically, it has overcome the problems caused by permanent metal stents, so it is the development direction to use the biodegradable magnesium alloy in future. The authors believe that biodegradable magnesium alloy stents will be widely used in interventional procedures for many diseases. (authors)

  2. A Review on Recent Advances in Stabilizing Peptides/Proteins upon Fabrication in Hydrogels from Biodegradable Polymers

    OpenAIRE

    Faisal Raza; Hajra Zafar; Ying Zhu; Yuan Ren; Aftab -Ullah; Asif Ullah Khan; Xinyi He; Han Han; Md Aquib; Kofi Oti Boakye-Yiadom; Liang Ge

    2018-01-01

    Hydrogels evolved as an outstanding carrier material for local and controlled drug delivery that tend to overcome the shortcomings of old conventional dosage forms for small drugs (NSAIDS) and large peptides and proteins. The aqueous swellable and crosslinked polymeric network structure of hydrogels is composed of various natural, synthetic and semisynthetic biodegradable polymers. Hydrogels have remarkable properties of functionality, reversibility, sterilizability, and biocompatibility. All...

  3. 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

  4. In vitro study of a new biodegradable nanocomposite based on poly propylene fumarate as bone glue

    Energy Technology Data Exchange (ETDEWEB)

    Shahbazi, S.; Moztarzadeh, F. [Department of Medical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Sadeghi, G. Mir Mohamad [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Jafari, Y., E-mail: y.j.arisman@gmail.com [Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan (Iran, Islamic Republic of)

    2016-12-01

    A novel poly propylene fumarate (PPF)-based glue which is reinforced by nanobioactive glass (NBG) particles and promoted by hydroxyethyl methacrylate (HEMA) as crosslinker agent, was developed and investigated for bone-to-bone bonding applications. In-vitro bioactivity, biodegradability, biocompatibility, and bone adhesion were tested and the results have verified that it can be used as bone glue. In an in-vitro condition, the prepared nanocomposite (PPF/HEMA/NBG) showed improved adhesion to wet bone surfaces. The combined tension and shear resistance between two wet bone surfaces was measured, and its maximum value was 9 ± 59 MPa. To investigate the bioactivity and biodegradability of the nanocomposite, it has been immersed in simulated body fluid (SBF). After 14 days exposure to SBF, a hydroxyapatite (HA) layer formed on the surface of the composite confirms the bioactivity of this material. In the XRD pattern of the nanocomposite surface, the HA characteristic diffraction peak at θ = 26 and 31.8 were observed. Also, by monitoring the weight change after 8 weeks immersion in SBF, the mass loss was about 16.46 wt%. It has been confirmed that this nanocomposite is a biodegradable material. Also, bioactivity and biodegradability of nanocomposite have been proved by SEM images. It has been showed that by using NBG particles and HEMA precursor, mechanical properties increased significantly. The ultimate tensile strength (UTS) of nanocomposite which contains 20% NBG and the ratio of 70/30 wt% PPF/HEMA (PHB.732) was approximately 62 MPa, while the UTS in the pure PPF/HEMA was about 32 MPa. High cell viability in this nanocomposite (MTT assays, 85–95%) can be attributed to the NBG nature which contains calcium phosphate and is similar to physiological environment. Furthermore, it possesses biomineralization and biodegradation which significantly affected by impregnation of hydrophilic HEMA in the PPF-based polymeric matrix. The results indicated that the new

  5. 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

  6. Biodegradation of endosulfan by mixed bacteria culture strains of ...

    African Journals Online (AJOL)

    Biodegradation of endosulfan by mixed bacteria culture strains of Pseudomonas aeruginosa and Staphylococcus aureus. Nsidibeabasi Calvin Nwokem, Calvin Onyedika Nwokem, Casmir Emmanuel Gimba, Beatrice Nkiruka Iwuala ...

  7. 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

  8. 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.

  9. Improving the osteogenesis of human bone marrow mesenchymal stem cell sheets by microRNA-21-loaded chitosan/hyaluronic acid nanoparticles via reverse transfection

    Directory of Open Access Journals (Sweden)

    Wang Z

    2016-05-01

    Full Text Available Zhongshan Wang,1 Guangsheng Wu,2,3 Mengying Wei,4 Qian Liu,1 Jian Zhou,1 Tian Qin,1 Xiaoke Feng,1 Huan Liu,1 Zhihong Feng,1 Yimin Zhao1 1State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, 2State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Periodontology, School of Stomatology, The Fourth Military Medical University, Xi’an, 3Qingdao First Sanatorium, Jinan Military Region, Qingdao, Shandong Province, 4Department of Biochemistry and Molecular Biology, The Fourth Military Medical University, Xi’an, People’s Republic of China Abstract: Cell sheet engineering has emerged as a novel approach to effectively deliver seeding cells for tissue regeneration, and developing human bone marrow mesenchymal stem cell (hBMMSC sheets with high osteogenic ability is a constant requirement from clinics for faster and higher-quality bone formation. In this work, we fabricated biocompatible and safe chitosan (CS/hyaluronic acid (HA nanoparticles (NPs to deliver microRNA-21 (miR-21, which has been proved to accelerate osteogenesis in hBMMSCs; then, the CS/HA/miR-21 NPs were cross-linked onto the surfaces of culture plates with 0.2% gel solution to fabricate miR-21-functionalized culture plates for reverse transfection. hBMMSC sheets were induced continuously for 14 days using a vitamin C-rich method on the miR-21-functionalized culture plates. For the characterization of CS/HA/miR-21 NPs, the particle size, zeta potential, surface morphology, and gel retardation were sequentially investigated. Then, the biological effects of hBMMSC sheets on the miR-21-functionalized culture plates were evaluated. The assay results demonstrated that the hBMMSC sheets could be successfully induced via the novel reverse transfection approach, and miR-21 delivery significantly enhanced the in vitro osteogenic differentiation of hBMMSC sheets in terms of upregulating calcification-related gene expression and enhancing alkaline phosphatase production, collagen secretion, and mineralized nodule formation. The enhanced osteogenic activity of hBMMSC sheets might promisingly lead to more rapid and more robust bone regeneration for clinical use. Keywords: human bone marrow MSCs, cell sheets, microRNA, chitosan, nanoparticles, osteogenic differentiation

  10. Microarc-oxidized titanium surfaces functionalized with microRNA-21-loaded chitosan/hyaluronic acid nanoparticles promote the osteogenic differentiation of human bone marrow mesenchymal stem cells.

    Science.gov (United States)

    Wang, Zhongshan; Wu, Guangsheng; Feng, Zhihong; Bai, Shizhu; Dong, Yan; Wu, Guofeng; Zhao, Yimin

    2015-01-01

    Dental implants have been widely used for the replacement of missing teeth in the clinic, but further improvements are needed to meet the clinical demands for faster and tighter osseointegration. In this study, we fabricated safe and biocompatible chitosan (CS)/hyaluronic acid (HA) nanoparticles to deliver microRNA-21 (miR-21) and thereby accelerate osteogenesis in human bone marrow mesenchymal stem cells (hBMMSCs). The CS/HA/miR-21 nanoparticles were cross-linked with 0.2% gel solution onto microarc oxidation (MAO)-treated titanium (Ti) surfaces to fabricate the miR-21-functionalized MAO Ti surface, resulting in the development of a novel coating for reverse transfection. To characterize the CS/HA/miR-21 nanoparticles, their particle size, zeta potential, surface morphology, and gel retardation ability were sequentially investigated. Their biological effects, such as cell viability, cytotoxicity, and expression of osteogenic genes by hBMMSCs on the miR-21-functionalized MAO Ti surfaces, were evaluated. Finally, we explored appropriate CS/HA/miR-21 nanoparticles with a CS/HA ratio of 4:1 and N/P ratio 20:1 for transfection, which presented good spherical morphology, an average diameter of 160.4±10.75 nm, and a positive zeta potential. The miR-21-functionalized MAO Ti surfaces demonstrated cell viability, cytotoxicity, and cell spreading comparable to those exhibited by naked MAO Ti surfaces and led to significantly higher expression of osteogenic genes. This novel miR-21-functionalized Ti implant may be used in the clinic to allow more effective and robust osseointegration.

  11. In vitro and in vivo gene delivery using chitosan/hyaluronic acid nanoparticles: Influences of molecular mass of hyaluronic acid and lyophilization on transfection efficiency.

    Science.gov (United States)

    Sato, Toshinori; Nakata, Mitsuhiro; Yang, Zhihong; Torizuka, Yu; Kishimoto, Satoko; Ishihara, Masayuki

    2017-08-01

    Lyophilization is an effective method for preserving nonviral gene vectors. To improve the stability and transgene expression of lyophilized plasmid DNA (pDNA) complexes, we coated the surfaces of pDNA/chitosan complexes with hyaluronic acid (HA) of varying molecular masses. The transgene expression of pDNA/chitosan/HA ternary complexes was characterized in vitro and in vivo. pDNA complexes were lyophilized overnight and the resultant products with spongy, porous consistencies were stored at -30, 4 or 25°C for 2 weeks. Rehydrated complexes were characterized using gel retardation assays, aiming to confirm complex formation, measure particle size and evaluate zeta potential, as well as conduct luciferase gene reporter assays. The anti-tumor effects of pDNA ternary complexes were evaluated using suicide gene (pTK) coding thymidine kinase in Huh7-implanted mice. Transfection efficiencies of pDNA/chitosan/HA ternary complexes were dependent on the average molecular masses of HA. The coating of pDNA/chitosan complexes with HA maintained the cellular transfection efficiencies of lyophilized pDNA ternary complexes. Furthermore, intratumoral injection of lyophilized, rehydrated pDNA ternary complexes into tumor-bearing mice showed a significant suppression of tumor growth. The coating of pDNA/chitosan complexes with high-molecular-weight HA augmented the stability and cellular transfection ability of the complexes after lyophilization-rehydration. Copyright © 2017 John Wiley & Sons, Ltd.

  12. Microarc-oxidized titanium surfaces functionalized with microRNA-21-loaded chitosan/hyaluronic acid nanoparticles promote the osteogenic differentiation of human bone marrow mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Wang Z

    2015-10-01

    Full Text Available Zhongshan Wang,1,* Guangsheng Wu,2,3,* Zhihong Feng,1 Shizhu Bai,1 Yan Dong,1 Guofeng Wu,1 Yimin Zhao1 1State Key Laboratory of Military Stomatology, Department of Prosthetic Dentistry, 2State Key Laboratory of Military Stomatology, Department of Periodontology, School of Stomatology, The Fourth Military Medical University, Xi’an, People’s Republic of China; 3Qingdao First Sanatorium, Jinan Military Region, Qingdao, Shandong Province, People’s Republic of China *These authors contributed equally to this work Abstract: Dental implants have been widely used for the replacement of missing teeth in the clinic, but further improvements are needed to meet the clinical demands for faster and tighter osseointegration. In this study, we fabricated safe and biocompatible chitosan (CS/hyaluronic acid (HA nanoparticles to deliver microRNA-21 (miR-21 and thereby accelerate osteogenesis in human bone marrow mesenchymal stem cells (hBMMSCs. The CS/HA/miR-21 nanoparticles were cross-linked with 0.2% gel solution onto microarc oxidation (MAO-treated titanium (Ti surfaces to fabricate the miR-21-functionalized MAO Ti surface, resulting in the development of a novel coating for reverse transfection. To characterize the CS/HA/miR-21 nanoparticles, their particle size, zeta potential, surface morphology, and gel retardation ability were sequentially investigated. Their biological effects, such as cell viability, cytotoxicity, and expression of osteogenic genes by hBMMSCs on the miR-21-functionalized MAO Ti surfaces, were evaluated. Finally, we explored appropriate CS/HA/miR-21 nanoparticles with a CS/HA ratio of 4:1 and N/P ratio 20:1 for transfection, which presented good spherical morphology, an average diameter of 160.4±10.75 nm, and a positive zeta potential. The miR-21-functionalized MAO Ti surfaces demonstrated cell viability, cytotoxicity, and cell spreading comparable to those exhibited by naked MAO Ti surfaces and led to significantly higher expression of osteogenic genes. This novel miR-21-functionalized Ti implant may be used in the clinic to allow more effective and robust osseointegration. Keywords: titanium implants, microarc oxidation, human bone marrow MSCs, microRNA, nanoparticles, osteogenic differentiation

  13. The effect of layer-by-layer chitosan-hyaluronic acid coating on graft-to-bone healing of a poly(ethylene terephthalate) artificial ligament.

    Science.gov (United States)

    Li, Hong; Ge, Yunsheng; Zhang, Pengyun; Wu, Lingxiang; Chen, Shiyi

    2012-01-01

    Surface coating with an organic layer-by-layer self-assembled template of chitosan and hyaluronic acid on a poly(ethylene terephthalate) (PET) artificial ligament was designed for the promotion and enhancement of graft-to-bone healing after artificial ligament implantation in a bone tunnel. The results of in vitro culturing of MC3T3-E1 mouse osteoblastic cells supported the hypothesis that the layer-by-layer coating of chitosan and hyaluronic acid could promote the cell compatibility of grafts and could promote osteoblast proliferation. A rabbit extra-articular tendon-to-bone healing model was used to evaluate the effect of this kind of surface-modified stainless artificial ligament in vivo. The final results proved that this organic compound coating could significantly promote and enhance new bone formation at the graft-bone interface histologically and, correspondingly, the experimental group with coating had significantly higher biomechanical properties compared with controls at 8 weeks (P < 0.05).

  14. Culture on 3D Chitosan-Hyaluronic Acid Scaffolds Enhances Stem Cell Marker Expression and Drug Resistance in Human Glioblastoma Cancer Stem Cells.

    Science.gov (United States)

    Wang, Kui; Kievit, Forrest M; Erickson, Ariane E; Silber, John R; Ellenbogen, Richard G; Zhang, Miqin

    2016-12-01

    The lack of in vitro models that support the growth of glioblastoma (GBM) stem cells (GSCs) that underlie clinical aggressiveness hinders developing new, effective therapies for GBM. While orthotopic patient-derived xenograft models of GBM best reflect in vivo tumor behavior, establishing xenografts is a time consuming, costly, and frequently unsuccessful endeavor. To address these limitations, a 3D porous scaffold composed of chitosan and hyaluronic acid (CHA) is synthesized. Growth and expression of the cancer stem cell (CSC) phenotype of the GSC GBM6 taken directly from fresh xenogratfs grown on scaffolds or as adherent monolayers is compared. While 2D adherent cultures grow as monolayers of flat epitheliod cells, GBM6 cells proliferate within pores of CHA scaffolds as clusters of self-adherent ovoid cells. Growth on scaffolds is accompanied by greater expression of genes that mediate epithelial-mesenchymal transition and maintain a primitive, undifferentiated phenotype, hallmarks of CSCs. Scaffold-grown cells also display higher expression of genes that promote resistance to hypoxia-induced oxidative stress. In accord, scaffold-grown cells show markedly greater resistance to clinically utilized alkylating agents compared to adherent cells. These findings suggest that our CHA scaffolds better mimic in vivo biological and clinical behavior and provide insights for developing novel individualized treatments. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Preparation of new biodegradable materials by grafting of polycarprolactone onto starch and their biodegradability studies

    International Nuclear Information System (INIS)

    Najemi, L.; Zerroukhi, A.; Jeanmaire, T.; Raihane, M.; Chamkh, F.; Qatibi, A.; Bennisse, R.

    2009-01-01

    The starch is a natural polymer which has the advantage of being biodegradable, renewable in quantity unlimited at very accessible prices. However its poor mechanical properties, depending on its hydrophobic character, and also its absorption of water restrict is applicability considerable especially for packing. (Author)

  16. 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

  17. 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)

  18. 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.

  19. 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

  20. 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.).

  1. Development of biodegradable fungicide by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Keun; Kim, Dong Sub [KAERI, Daejeon (Korea, Republic of)

    2011-01-15

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by pot experiment and It was promising to prevent pepper, Chinese cabbage and radish from anthrax, phytophthora and root rot

  2. Development of biodegradable fungicide by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngkeun; Kim, Dongsub

    2012-03-15

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by field test and it was promising to prevent Chinese cabbage and radish from phytophthora and root rot.

  3. Biodegradation of petroleum hydrocarbons in hypersaline environments

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Martins

    2012-09-01

    Full Text Available Literature on hydrocarbon degradation in extreme hypersaline media presents studies that point to a negative effect of salinity increase on hydrocarbonoclastic activity, while several others report an opposite tendency. Based on information available in the literature, we present a discussion on the reasons that justify these contrary results. Despite the fact that microbial ability to metabolize hydrocarbons is found in extreme hypersaline media, indeed some factors are critical for the occurrence of hydrocarbon degradation in such environments. How these factors affect hydrocarbon degradation and their implications for the assessment of hydrocarbon biodegradation in hypersaline environments are presented in this review.

  4. Development of biodegradable fungicide by radiation

    International Nuclear Information System (INIS)

    Lee, Young Keun; Kim, Dong Sub

    2011-01-01

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by pot experiment and It was promising to prevent pepper, Chinese cabbage and radish from anthrax, phytophthora and root rot

  5. Biodegradation of the Nitramine Explosive CL-20

    OpenAIRE

    Trott, Sandra; Nishino, Shirley F.; Hawari, Jalal; Spain, Jim C.

    2003-01-01

    The cyclic nitramine explosive CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) was examined in soil microcosms to determine whether it is biodegradable. CL-20 was incubated with a variety of soils. The explosive disappeared in all microcosms except the controls in which microbial activity had been inhibited. CL-20 was degraded most rapidly in garden soil. After 2 days of incubation, about 80% of the initial CL-20 had disappeared. A CL-20-degrading bacterial strain, Agrobact...

  6. 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.)

  7. 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.)

  8. Biodegradation of polyurethanes; Polyurethane no biseibutsu bunkai

    Energy Technology Data Exchange (ETDEWEB)

    Kinpara, N; Ando, M; Ohira, Z [Suzuki Motor Corp., Shizuoka (Japan); Nakajima, T; Nakahara, T [University of Tsukuba, Tsukuba (Japan)

    1997-10-01

    Different types of Polyurethane (PUR) are used for various industrial products and are used in increasing quantities every year. We experimented with biodegradation of PURs to dispose of industrial wastes. 2 strains of fungi and 1 strain of bacteria which were seemed to have the ability to degrade PURs well were isolated from various soils and waste water. These strains could degrade ester-type PUR and PUR made from a mixture of ester and ether. However, these strains could not degrade ether-type PUR. From Scanning Electron Microscopy observation, it is suggested that the microbial degradation proceeded in at least 2 patterns. 4 refs., 8 figs., 2 tabs.

  9. Development of biodegradable fungicide by radiation

    International Nuclear Information System (INIS)

    Lee, Young Jeun; Kim, Dong Sub

    2010-01-01

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Sixteen antifungal microbes were isolated and 4 antifungal activity enhanced mutants were induced by using radiation. P. lentimorbus WJ5a17 had 41% higher antifungal activity than the wild type. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified

  10. Development of biodegradable fungicide by radiation

    International Nuclear Information System (INIS)

    Lee, Youngkeun; Kim, Dongsub

    2012-03-01

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by field test and it was promising to prevent Chinese cabbage and radish from phytophthora and root rot

  11. 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.

  12. 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)

  13. 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.

  14. 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.

  15. 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)

  16. 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)

  17. 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.

  18. Methods for Evaluating the Biodegradability of Environmentally Degradable Polymers

    NARCIS (Netherlands)

    Zee, van der M.

    2014-01-01

    This chapter presents an overview of the current knowledge on experimental methods for monitoring the biodegradability of polymeric materials. The focus is, in particular, on the biodegradation of materials under environmental conditions. Examples of in vivo degradation of polymers used in

  19. Biodegradability of unused lubricating brake fluids in fresh and ...

    African Journals Online (AJOL)

    The biodegradability of four unused lubricating brake fluids (Total brake fluid, Allied brake fluid, Oando brake fluid and Ate brake fluid) was carried out in fresh and marine water obtained from Isiokpo stream and Bonny river of the Niger Delta, South South Nigeria. Biodegradability, of the brake fluids were obtained after a 56 ...

  20. 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.

  1. 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.

  2. 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.

  3. Biodegradable elastomers for biomedical applications and regenerative medicine

    NARCIS (Netherlands)

    Bat, Erhan; Zhang, Zheng; Feijen, Jan; Grijpma, Dirk W.; Poot, Andre A.

    Synthetic biodegradable polymers are of great value for the preparation of implants that are required to reside only temporarily in the body. The use of biodegradable polymers obviates the need for a second surgery to remove the implant, which is the case when a nondegradable implant is used. After

  4. Fungal biodegradation of plantain peel for broiler finisher feeding: In ...

    African Journals Online (AJOL)

    ... protein, cholesterol and glucose were significantly (P<0.05) affected by the treatments. Fungal biodegradation of PPL using A.niger has the potential of enhancing feed intake, nutrient digestibility and the body weight gain of broiler finisher. Keywords: Aspergillus niger, biodegradation, nutrient enhancement and broilers.

  5. Biodegradable hollow fibres for the controlled release of drugs

    NARCIS (Netherlands)

    Schakenraad, J.M.; Oosterbaan, J.A.; Nieuwenhuis, P.; Molenaar, I.; Olijslager, J.; Potman, W.; Eenink, M.J.D.; Feijen, Jan

    1988-01-01

    Biodegradable hollow fibres of poly-l-lactic acid (PLLA) filled with a suspension of the contraceptive hormone levonorgestrel in castor oil were implanted subcutaneously in rats to study the rate of drug release, rate of biodegradation and tissue reaction caused by the implant. The in vivo drug

  6. 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.

  7. 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)

  8. 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...

  9. 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.

  10. 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

  11. Evaluation of Artificial Intelligence Based Models for Chemical Biodegradability Prediction

    Directory of Open Access Journals (Sweden)

    Aleksandar Sabljic

    2004-12-01

    Full Text Available This study presents a review of biodegradability modeling efforts including a detailed assessment of two models developed using an artificial intelligence based methodology. Validation results for these models using an independent, quality reviewed database, demonstrate that the models perform well when compared to another commonly used biodegradability model, against the same data. The ability of models induced by an artificial intelligence methodology to accommodate complex interactions in detailed systems, and the demonstrated reliability of the approach evaluated by this study, indicate that the methodology may have application in broadening the scope of biodegradability models. Given adequate data for biodegradability of chemicals under environmental conditions, this may allow for the development of future models that include such things as surface interface impacts on biodegradability for example.

  12. [Progress on biodegradation of polylactic acid--a review].

    Science.gov (United States)

    Li, Fan; Wang, Sha; Liu, Weifeng; Chen, Guanjun

    2008-02-01

    Polylactic acid is a high molecular-weight polyester made from renewable resources such as corn or starch. It is a promising biodegradable plastic due to its mechanical properties, biocompatibility and biodegradability. To achieve natural recycling of polylactic acid, relative microorganisms and the underlying mechanisms in the biodegradation has become an important issue in biodegradable materials. Up to date, most isolated microbes capable of degrading polylactic acid belong to actinomycetes. Proteases secreted by these microorganisms are responsible for the degradation. However, subtle differences exist between these polylactic acid degrading enzymes and typical proteases with respect to substrate binding and catalysis. Amino acids relative to catalysis are postulated to be highly plastic allowing their catalytic hydrolysis of polylactic acid. In this paper we reviewed current studies on biodegradation of polylactic acid concerning its microbial, enzymatic reactions and the possible mechanisms. We also discussed the probability of biologically recycling PLA by applying highly efficient strains and enzymes.

  13. Biodegradation of nonylphenol in river sediment

    International Nuclear Information System (INIS)

    Yuan, S.Y.; Yu, C.H.; Chang, B.V.

    2004-01-01

    We investigated the biodegradation of nonylphenol monoethoxylate (NP1EO) and nonylphenol (NP) by aerobic microbes in sediment samples collected at four sites along the Erren River in southern Taiwan. Aerobic degradation rate constants (k 1 ) and half-lives (t 1/2 ) for NP (2 μg g -1 ) ranged from 0.007 to 0.051 day -1 and 13.6 to 99.0 days, respectively; for NP1EO (2 μg g -1 ) the ranges were 0.006 to 0.010 day -1 and 69.3 to 115.5 days. Aerobic degradation rates for NP and NP1EO were enhanced by shaking and increased temperature, and delayed by the addition of Pb, Cd, Cu, Zn, phthalic acid esters (PAEs), and NaCl, as well as by reduced levels of ammonium, phosphate, and sulfate. Of the microorganism strains isolated from the sediment samples, we found that strain JC1 (identified as Pseudomonas sp.) expressed the best biodegrading ability. Also noted was the presence of 4'-amino-acetophenone, an intermediate product resulting from the aerobic degradation of NP by Pseudomonas sp. - The effects of manipulating several factors on nonylphenol and nonylphenol monoethoxylate degradation in river sediment were analysed

  14. Fabrication of environmentally biodegradable lignin nanoparticles.

    Science.gov (United States)

    Frangville, Camille; Rutkevičius, Marius; Richter, Alexander P; Velev, Orlin D; Stoyanov, Simeon D; Paunov, Vesselin N

    2012-12-21

    We developed a method for the fabrication of novel biodegradable nanoparticles (NPs) from lignin which are apparently non-toxic for microalgae and yeast. We compare two alternative methods for the synthesis of lignin NPs which result in particles of very different stability upon change of pH. The first method is based on precipitation of low-sulfonated lignin from an ethylene glycol solution by using diluted acidic aqueous solutions, which yields lignin NPs that are stable over a wide range of pH. The second approach is based on the acidic precipitation of lignin from a high-pH aqueous solution which produces NPs stable only at low pH. Our study reveals that lignin NPs from the ethylene glycol-based precipitation contain densely packed lignin domains which explain the stability of the NPs even at high pH. We characterised the properties of the produced lignin NPs and determined their loading capacities with hydrophilic actives. The results suggest that these NPs are highly porous and consist of smaller lignin domains. Tests with microalgae like Chlamydomonas reinhardtii and yeast incubated in lignin NP dispersions indicated that these NPs lack measurable effect on the viability of these microorganisms. Such biodegradable and environmentally compatible NPs can find applications as drug delivery vehicles, stabilisers of cosmetic and pharmaceutical formulations, or in other areas where they may replace more expensive and potentially toxic nanomaterials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Immunological Response to Biodegradable Magnesium Implants

    Science.gov (United States)

    Pichler, Karin; Fischerauer, Stefan; Ferlic, Peter; Martinelli, Elisabeth; Brezinsek, Hans-Peter; Uggowitzer, Peter J.; Löffler, Jörg F.; Weinberg, Annelie-Martina

    2014-04-01

    The use of biodegradable magnesium implants in pediatric trauma surgery would render surgical interventions for implant removal after tissue healing unnecessary, thereby preventing stress to the children and reducing therapy costs. In this study, we report on the immunological response to biodegradable magnesium implants—as an important aspect in evaluating biocompatibility—tested in a growing rat model. The focus of this study was to investigate the response of the innate immune system to either fast or slow degrading magnesium pins, which were implanted into the femoral bones of 5-week-old rats. The main alloying element of the fast-degrading alloy (ZX50) was Zn, while it was Y in the slow-degrading implant (WZ21). Our results demonstrate that degrading magnesium implants beneficially influence the immune system, especially in the first postoperative weeks but also during tissue healing and early bone remodeling. However, rodents with WZ21 pins showed a slightly decreased phagocytic ability during bone remodeling when the degradation rate reached its maximum. This may be due to the high release rate of the rare earth-element yttrium, which is potentially toxic. From our results we conclude that magnesium implants have a beneficial effect on the innate immune system but that there are some concerns regarding the use of yttrium-alloyed magnesium implants, especially in pediatric patients.

  16. Polymeric Biodegradable Stent Insertion in the Esophagus

    Directory of Open Access Journals (Sweden)

    Kai Yang

    2016-04-01

    Full Text Available Esophageal stent insertion has been used as a well-accepted and effective alternative to manage and improve the quality of life for patients diagnosed with esophageal diseases and disorders. Current stents are either permanent or temporary and are fabricated from either metal or plastic. The partially covered self-expanding metal stent (SEMS has a firm anchoring effect and prevent stent migration, however, the hyperplastic tissue reaction cause stent restenosis and make it difficult to remove. A fully covered SEMS and self-expanding plastic stent (SEPS reduced reactive hyperplasia but has a high migration rate. The main advantage that polymeric biodegradable stents (BDSs have over metal or plastic stents is that removal is not require and reduce the need for repeated stent insertion. But the slightly lower radial force of BDS may be its main shortcoming and a post-implant problem. Thus, strengthening support of BDS is a content of the research in the future. BDSs are often temporarily effective in esophageal stricture to relieve dysphagia. In the future, it can be expect that biodegradable drug-eluting stents (DES will be available to treat benign esophageal stricture, perforations or leaks with additional use as palliative modalities for treating malignant esophageal stricture, as the bridge to surgery or to maintain luminal patency during neoadjuvant chemoradiation.

  17. Production of biodegradable plastic from agricultural wastes

    Directory of Open Access Journals (Sweden)

    N.A. Mostafa

    2018-05-01

    Full Text Available Agricultural residues management is considered to be a vital strategy in order to accomplish resource conservation and to maintain the quality of the environment. In recent years, biofibers have attracted increasing interest due to their wide applications in food packaging and in the biomedical sciences. These eco-friendly polymers reduce rapidly and replace the usage of the petroleum-based synthetic polymers due to their safety, low production costs, and biodegradability. This paper reports an efficient method for the production of the cellulose acetate biofiber from flax fibers and cotton linters. The used process satisfied a yield of 81% and 54% for flax fibers and cotton linters respectively (based on the weight of the cellulosic residue used. The structure of the produced bioplastic was confirmed by X-ray diffraction, FT-IR and gel permeation chromatography. Moreover, this new biopolymer is biodegradable and is not affected by acid or salt treatment but is alkali labile. A comparison test showed that the produced cellulose acetate was affected by acids to a lesser extent than polypropylene and polystyrene. Therefore, this new cellulose acetate bioplastics can be applied in both the food industry and medicine. Keywords: Cotton linters, Flax fibers, Cellulose acetate, Preparation, Characterization

  18. A REVIEW ON BIODEGRADABLE STARCH BASED FILM

    Directory of Open Access Journals (Sweden)

    Hooman Molavi

    2015-04-01

    Full Text Available In recent years, biodegradable edible films have become very important in research related to food, due to their compatibility with the environment and their use in the food packaging industry. Various sources can be used in the production of biopolymers as biodegradable films that include polysaccharides, proteins and lipids. Among the various polysaccharides, starch due to its low price and its abundance in nature is of significant importance. Several factors affect the properties of starch films; such as the source which starch is obtained from, as well as the ratio of constituents of the starch. Starch films have advantages such as low thickness, flexibility and transparency though; there are some downsides to mention, such as the poor mechanical properties and water vapor permeability. Thus, using starch alone to produce the film will led to restrictions on its use. To improve the mechanical properties of starch films and also increases resistance against humidity, several methods can be used; including the starch modifying techniques such as cross linking of starch and combining starch with other natural polymers. Other methods such as the use of lipid in formulations of films to increase the resistance to moisture are possible, but lipids are susceptible to oxidation. Therefore, new approaches are based on the integration of different biopolymers in food packaging.

  19. 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].

  20. Hydrocarbon biodegradation in intertidal wetland sediments.

    Science.gov (United States)

    McGenity, Terry J

    2014-06-01

    Intertidal wetlands, primarily salt marsh, mangrove and mudflats, which provide many essential ecosystem services, are under threat on numerous fronts; a situation that is made worse by crude-oil pollution. Microbes are the main vehicle for remediation of such sediments, and new discoveries, such as novel biodegradation pathways, means of accessing oil, multi-species interactions, and community-level responses to oil addition, are helping us to understand, predict and monitor the fate of oil. Despite this, there are many challenges, not least because of the heterogeneity of these ecosystems and the complexity of crude oil. For example, there is growing awareness about the toxicity of the oxygenated products that result from crude-oil weathering, which are difficult to degrade. This review highlights how developments in areas as diverse as systems biology, microbiology, ecology, biogeochemistry and analytical chemistry are enhancing our understanding of hydrocarbon biodegradation and thus bioremediation of oil-polluted intertidal wetlands. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Computer Optimization of Biodegradable Nanoparticles Fabricated by Dispersion Polymerization

    Directory of Open Access Journals (Sweden)

    Emmanuel O. Akala

    2015-12-01

    Full Text Available Quality by design (QbD in the pharmaceutical industry involves designing and developing drug formulations and manufacturing processes which ensure predefined drug product specifications. QbD helps to understand how process and formulation variables affect product characteristics and subsequent optimization of these variables vis-à-vis final specifications. Statistical design of experiments (DoE identifies important parameters in a pharmaceutical dosage form design followed by optimizing the parameters with respect to certain specifications. DoE establishes in mathematical form the relationships between critical process parameters together with critical material attributes and critical quality attributes. We focused on the fabrication of biodegradable nanoparticles by dispersion polymerization. Aided by a statistical software, d-optimal mixture design was used to vary the components (crosslinker, initiator, stabilizer, and macromonomers to obtain twenty nanoparticle formulations (PLLA-based nanoparticles and thirty formulations (poly-ɛ-caprolactone-based nanoparticles. Scheffe polynomial models were generated to predict particle size (nm, zeta potential, and yield (% as functions of the composition of the formulations. Simultaneous optimizations were carried out on the response variables. Solutions were returned from simultaneous optimization of the response variables for component combinations to (1 minimize nanoparticle size; (2 maximize the surface negative zeta potential; and (3 maximize percent yield to make the nanoparticle fabrication an economic proposition.

  2. 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

  3. 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.

  4. 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.

  5. 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)

  6. 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

  7. Biopolymer-based thermoplastic mixture for producing solid biodegradable shaped bodies and its photo degradation stability

    Science.gov (United States)

    Sulong, Nurulsaidatulsyida; Rus, Anika Zafiah M.

    2013-12-01

    In recent years, biopolymers with controllable lifetimes have become increasingly important for many applications in the areas of agriculture, biomedical implants and drug release, forestry, wild life conservation and waste management. Natural oils are considered to be the most important class of renewable sources. They can be obtained from naturally occurring plants, such as sunflower, cotton, linseed and palm oil. In Malaysia, palm oil is an inexpensive and commodity material. Biopolymer produced from palm oil (Bio-VOP) is a naturally occurring biodegradable polymer and readily available from agriculture. For packaging use however, Bio-VOP is not thermoplastic and its granular form is unsuitable for most uses in the plastics industry, mainly due to processing difficulties during extrusion or injection moulding. Thus, research workers have developed several methods to blend Bio-VOP appropriately for industrial uses. In particular, injections moulding processes, graft copolymerisation, and preparation of blends with thermoplastic polymers have been studied to produce solid biodegradable shaped bodies. HDPE was chosen as commercial thermoplastic materials and was added with 10% Bio-VOP for the preparation of solid biodegradable shaped bodies named as HD-VOP. The UV light exposure of HD-VOP at 12 minutes upon gives the highest strength of this material that is 17.6 MPa. The morphological structure of HD-VOP shows dwi structure surface fracture which is brittle and ductile properties.

  8. Observation on the biodegradation and bioremediation potential of methyl t-butyl ether

    International Nuclear Information System (INIS)

    Salanitro, J.; Wisniewski, H.; McAllister, P.

    1995-01-01

    There have been few reports documenting evidence for the biodegradation of the fuel oxygenate alkyl ether, methyl t-butyl ether (MTBE) in groundwater, soils, and biosludges. Partial (or complete) microbial breakdown of MTBE has been observed in an anaerobic subsoil, a river sediment under methanogenic conditions, a cyclohexane-degrading bacterial consortium and a pure culture of the methylotroph, Methylisnus trichosporium OB3b. An aerobic bacterial enrichment (BC-1) isolated from an industrial transient (non-accumulating) metabolic intermediate. The studies suggest that MTBE is cleaved by BC-1 to TBA which is then metabolized via isopropanol and acetone. There is little information on the occurrence of indigenous MTBE-degraders in groundwater, soils and activated sludges. Preliminary evidence has been obtained, however, from a marketing terminal groundwater site that naturally-occurring MTBE-degraders are present in some monitoring wells. Microcosm experiments with groundwater from this aquifer show that MTBE is aerobically degraded (no TBA formed) with a first-order decay rate (0.31/day) similar to BTEX. Also, MTBE did not inhibit the intrinsic biodegradation potential of BTEX in groundwater microcosms. In summary, the data presented indicate that MTBE biodegradation has been observed in some environmental media. Further work is needed to assess the feasibility of using indigenous or derived aerobic and anaerobic MTBE-degrading cultures for treating fuel ethers in groundwaters or wastewater with in-situ or ex-situ bioremediation technologies

  9. Spatially discrete thermal drawing of biodegradable microneedles for vascular drug delivery.

    Science.gov (United States)

    Choi, Chang Kuk; Lee, Kang Ju; Youn, Young Nam; Jang, Eui Hwa; Kim, Woong; Min, Byung-Kwon; Ryu, WonHyoung

    2013-02-01

    Spatially discrete thermal drawing is introduced as a novel method for the fabrication of biodegradable microneedles with ultra-sharp tip ends. This method provides the enhanced control of microneedle shapes by spatially controlling the temperature of drawn polymer as well as drawing steps and speeds. Particular focus is given on the formation of sharp tip ends of microneedles at the end of thermal drawing. Previous works relied on the fracture of polymer neck by fast drawing that often causes uncontrolled shapes of microneedle tips. Instead, this approach utilizes the surface energy of heated polymer to form ultra-sharp tip ends. We have investigated the effect of such temperature control, drawing speed, and drawing steps in thermal drawing process on the final shape of microneedles using biodegradable polymers. XRD analysis was performed to analyze the effect of thermal cycle on the biodegradable polymer. Load-displacement measurement also showed the dependency of mechanical strengths of microneedles on the microneedle shapes. Ex vivo vascular tissue insertion and drug delivery demonstrated microneedle insertion to tunica media layer of canine aorta and drug distribution in the tissue layer. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. In vitro investigations of a novel wound dressing concept based on biodegradable polyurethane

    International Nuclear Information System (INIS)

    Rottmar, Markus; Richter, Michael; Mäder, Xenia; Grieder, Kathrin; Bruinink, Arie; Nuss, Katja; Karol, Agnieszka; Rechenberg, Brigitte von; Zimmermann, Erika; Buser, Stephan; Dobmann, Andreas; Blume, Jessica

    2015-01-01

    Non-healing and partially healing wounds are an important problem not only for the patient but also for the public health care system. Current treatment solutions are far from optimal regarding the chosen material properties as well as price and source. Biodegradable polyurethane (PUR) scaffolds have shown great promise for in vivo tissue engineering approaches, but accomplishment of the goal of scaffold degradation and new tissue formation developing in parallel has not been observed so far in skin wound repair. In this study, the mechanical properties and degradation behavior as well as the biocompatibility of a low-cost synthetic, pathogen-free, biocompatible and biodegradable extracellular matrix mimicking a PUR scaffold was evaluated in vitro. The novel PUR scaffolds were found to meet all the requirements for optimal scaffolds and wound dressings. These three-dimensional scaffolds are soft, highly porous, and form-stable and can be easily cut into any shape desired. All the material formulations investigated were found to be nontoxic. One formulation was able to be defined that supported both good fibroblast cell attachment and cell proliferation to colonize the scaffold. Tunable biodegradation velocity of the materials could be observed, and the results additionally indicated that calcium plays a crucial role in PUR degradation. Our results suggest that the PUR materials evaluated in this study are promising candidates for next-generation wound treatment systems and support the concept of using foam scaffolds for improved in vivo tissue engineering and regeneration. (focus issue paper)

  11. In vitro investigations of a novel wound dressing concept based on biodegradable polyurethane.

    Science.gov (United States)

    Rottmar, Markus; Richter, Michael; Mäder, Xenia; Grieder, Kathrin; Nuss, Katja; Karol, Agnieszka; von Rechenberg, Brigitte; Zimmermann, Erika; Buser, Stephan; Dobmann, Andreas; Blume, Jessica; Bruinink, Arie

    2015-06-01

    Non-healing and partially healing wounds are an important problem not only for the patient but also for the public health care system. Current treatment solutions are far from optimal regarding the chosen material properties as well as price and source. Biodegradable polyurethane (PUR) scaffolds have shown great promise for in vivo tissue engineering approaches, but accomplishment of the goal of scaffold degradation and new tissue formation developing in parallel has not been observed so far in skin wound repair. In this study, the mechanical properties and degradation behavior as well as the biocompatibility of a low-cost synthetic, pathogen-free, biocompatible and biodegradable extracellular matrix mimicking a PUR scaffold was evaluated in vitro . The novel PUR scaffolds were found to meet all the requirements for optimal scaffolds and wound dressings. These three-dimensional scaffolds are soft, highly porous, and form-stable and can be easily cut into any shape desired. All the material formulations investigated were found to be nontoxic. One formulation was able to be defined that supported both good fibroblast cell attachment and cell proliferation to colonize the scaffold. Tunable biodegradation velocity of the materials could be observed, and the results additionally indicated that calcium plays a crucial role in PUR degradation. Our results suggest that the PUR materials evaluated in this study are promising candidates for next-generation wound treatment systems and support the concept of using foam scaffolds for improved in vivo tissue engineering and regeneration.

  12. 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.

  13. Aquatic toxicity and biodegradability of advanced cationic surfactant APA-22 compatible with the aquatic environment.

    Science.gov (United States)

    Yamane, Masayuki; Toyo, Takamasa; Inoue, Katsuhisa; Sakai, Takaya; Kaneko, Youhei; Nishiyama, Naohiro

    2008-01-01

    Cationic surfactant is a chemical substance used in hair conditioner, fabric softener and other household products. By investigating the relationship between the aquatic toxicity and the chemical structures of two types of mono alkyl cationic surfactants, alkyl trimethylammonium salts and alkyl dimethylamine salts, we have found that the C22 alkyl chain length is effective to reduce the toxicity. Besides, we have recognized that the amidopropyl functional group contributes to the enhanced biodegradability by investigating the biodegradation trend of (alkylamidopropyl)dimethylamine salt (alkyl chain length: C18). Based on these findings, we have developed mono alkyl cationic surfactant called APA-22, N-[3-(dimethylamino)propyl]docosanamide salt. APA-22 is formed by the C22 alkyl chain, amidopropyl functional group and di-methyltertiary amine group. We evaluated the aerobic and anaerobic biodegradability of APA-22 by two standard methods (OECD Test Guideline 301B and ECETOC technical document No.28) and found that this substance was degraded rapidly in both conditions. The toxicity to algae, invertebrate and fish of this substance are evaluated by using OECD Test Guideline 201, 202 and 203, respectively. All acute toxicity values are >1 mg/L, which indicates that environmental toxicity of this substance is relatively less toxic to aquatic organism. In addition, we estimated the biodegradation pathway of APA-22 and observed the complete disappearance of APA-22 and its intermediates during the test periods. Based on the environmental data provided above, we concluded that APA22 is more compatible with the aquatic environment compared to other cationic surfactants with mono long alkyl chain.

  14. 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%.

  15. 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

  16. Lignin Biodegradation with Laccase-Mediator Systems

    International Nuclear Information System (INIS)

    Christopher, Lew Paul; Yao, Bin; Ji, Yun

    2014-01-01

    Lignin has a significant and largely unrealized potential as a source for the sustainable production of fuels and bulk high-value chemicals. It can replace fossil-based oil as a renewable feedstock that would bring about socio-economic and environmental benefits in our transition to a biobased economy. The efficient utilization of lignin however requires its depolymerization to low-molecular weight phenolics and aromatics that can then serve as the building blocks for chemical syntheses of high-value products. The ability of laccase to attack and degrade lignin in conjunction with laccase mediators is currently viewed as one of the potential “breakthrough” applications for lignin valorization. Here, we review the recent progress in lignin biodegradation with laccase-mediator systems, and research needs that need to be addressed in this field.

  17. Biodegradation of polyester. Polyester no bunkai sei

    Energy Technology Data Exchange (ETDEWEB)

    Tokiwa, Y. (Agency of Industrial Science and Technology, Tokyo (Japan). Fermentation Research Inst.)

    1991-09-10

    Penicillium sp. 14-3 and penicillium sp. 26-1 can degrade various kinds of polyester. The results of studies made on hydrolysis of polyester by enzyme, hydrolysis of polyester by various kinds of lipase, and degradation of ester type polyurethane by microbes and lipase are introduced. For the improvement of physical properties of aliphatic polyester, aromatic-aliphatic polyester copolymers (CPE) have been synthesized to study the biodegradability. Copolymer in which a number of polyamide (nylon) are alternately introduced (CPAE) to aliphatic polyester has been developed. The result of studies made on the degradability of a blended body of PCL and natural high polymer, and on the collapsibility by lipase of high polymer materials including aliphatic polyamide are introduced. 26 refs., 5 figs., 1 tab.

  18. Lignin Biodegradation with Laccase-Mediator Systems

    Energy Technology Data Exchange (ETDEWEB)

    Christopher, Lew Paul, E-mail: lew.christopher@sdsmt.edu [Center for Bioprocessing Research and Development, South Dakota School of Mines & Technology, Rapid City, SD (United States); Department of Civil and Environmental Engineering, South Dakota School of Mines & Technology, Rapid City, SD (United States); Yao, Bin [Center for Bioprocessing Research and Development, South Dakota School of Mines & Technology, Rapid City, SD (United States); Ji, Yun [Department of Chemical Engineering, University of North Dakota, Grand Forks, ND (United States)

    2014-03-31

    Lignin has a significant and largely unrealized potential as a source for the sustainable production of fuels and bulk high-value chemicals. It can replace fossil-based oil as a renewable feedstock that would bring about socio-economic and environmental benefits in our transition to a biobased economy. The efficient utilization of lignin however requires its depolymerization to low-molecular weight phenolics and aromatics that can then serve as the building blocks for chemical syntheses of high-value products. The ability of laccase to attack and degrade lignin in conjunction with laccase mediators is currently viewed as one of the potential “breakthrough” applications for lignin valorization. Here, we review the recent progress in lignin biodegradation with laccase-mediator systems, and research needs that need to be addressed in this field.

  19. Biodegradability of Poly(hydroxyalkanoate Materials

    Directory of Open Access Journals (Sweden)

    Keiji Numata

    2009-08-01

    Full Text Available Poly(hydroxyalkanoate (PHA, which is produced from renewable carbon resources by many microorganisms, is an environmentally compatible polymeric material and can be processed into films and fibers. Biodegradation of PHA material occurs due to the action of extracellular PHA depolymerase secreted from microorganisms in various natural environments. A key step in determining the overall enzymatic or environmental degradation rate of PHA material is the degradation of PHA lamellar crystals in materials; hence, the degradation mechanism of PHA lamellar crystals has been studied in detail over the last two decades. In this review, the relationship between crystal structure and enzymatic degradation behavior, in particular degradation rates, of films and fibers for PHA is described.

  20. Biodegradable polymeric nanocarriers for pulmonary drug delivery.

    Science.gov (United States)

    Rytting, Erik; Nguyen, Juliane; Wang, Xiaoying; Kissel, Thomas

    2008-06-01

    Pulmonary drug delivery is attractive for both local and systemic drug delivery as a non-invasive route that provides a large surface area, thin epithelial barrier, high blood flow and the avoidance of first-pass metabolism. Nanoparticles can be designed to have several advantages for controlled and targeted drug delivery, including controlled deposition, sustained release, reduced dosing frequency, as well as an appropriate size for avoiding alveolar macrophage clearance or promoting transepithelial transport. This review focuses on the development and application of biodegradable polymers to nanocarrier-based strategies for the delivery of drugs, peptides, proteins, genes, siRNA and vaccines by the pulmonary route. The selection of natural or synthetic materials is important in designing particles or nanoparticle clusters with the desired characteristics, such as biocompatibility, size, charge, drug release and polymer degradation rate.

  1. Biodegradation of concrete intended for their decontamination

    International Nuclear Information System (INIS)

    Jestin, A.

    2005-05-01

    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 microorganisms 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)

  2. 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

  3. Antibacterial biodegradable Mg-Ag alloys

    Directory of Open Access Journals (Sweden)

    D Tie

    2013-06-01

    Full Text Available The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solution (T4 and aging (T6 heat treatment.The metallurgical analysis and phase identification showed that all alloys contained Mg4Ag as the dominant β phase. After heat treatment, the mechanical properties of all Mg-Ag alloys were significantly improved and the corrosion rate was also significantly reduced, due to presence of silver. Mg(OH2 and MgO present the main magnesium corrosion products, while AgCl was found as the corresponding primary silver corrosion product. Immersion tests, under cell culture conditions, demonstrated that the silver content did not significantly shift the pH and magnesium ion release. In vitro tests, with both primary osteoblasts and cell lines (MG63, RAW 264.7, revealed that Mg-Ag alloys show negligible cytotoxicity and sound cytocompatibility. Antibacterial assays, performed in a dynamic bioreactor system, proved that the alloys reduce the viability of two common pathogenic bacteria, Staphylococcus aureus (DSMZ 20231 and Staphylococcus epidermidis (DSMZ 3269, and the results showed that the killing rate of the alloys against tested bacteria exceeded 90%. In summary, biodegradable Mg-Ag alloys are cytocompatible materials with adjustable mechanical and corrosion properties and show promising antibacterial activity, which indicates their potential as antibacterial biodegradable implant materials.

  4. (EOI) Form

    International Development Research Centre (IDRC) Digital Library (Canada)

    Dorine Odongo

    COLLABORATING TECHNICAL AGENCIES: EXPRESSION OF INTEREST FORM. • Please read the information provided about the initiative and the eligibility requirements in the Prospectus before completing this application form. • Ensure all the sections of the form are accurately completed and saved in PDF format.

  5. Modular forms

    NARCIS (Netherlands)

    Edixhoven, B.; van der Geer, G.; Moonen, B.; Edixhoven, B.; van der Geer, G.; Moonen, B.

    2008-01-01

    Modular forms are functions with an enormous amount of symmetry that play a central role in number theory, connecting it with analysis and geometry. They have played a prominent role in mathematics since the 19th century and their study continues to flourish today. Modular forms formed the

  6. 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)

  7. 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)

  8. Effect of chemical pretreatment on the biodegradation of cyanides

    International Nuclear Information System (INIS)

    Aronstein, B.N.; Paterek, J.R.; Rice, L.E.; Srivastava, V.J.

    1995-01-01

    The application of Fenton's reagent (H 2 O 2 ; Fe 2+ ) as a chemical pretreatment for acceleration of biological degradation of cyanides in soil-containing systems has been studied. In slurries of topsoil freshly amended with radiolabeled free cyanide (K 14 CN) at pH 7.2, about 100% of the compound was removed from the system by the combination of chemical oxidation and biodegradation. In slurry of manufactured gas plant (MGP) soil, the extent of combined chemical-biological treatment was 50%. At the same time, approximately 15% of the cyanide was lost from the system by protonation and evolution of formed HCN. In slurries of both topsoil and MGP soil amended with radiolabeled K 4 [Fe(CN) 6 ], less than 20% was degraded. In soils previously equilibrated with free and complex cyanide, the highest extent of degradation resulted from chemical-biological treatment did not exceed 15%. To avoid massive evolution of HCN, the cyanide-amended topsoil was maintained at a pH of 10.0. At this pH, nearly 35% of the cyanides were removed from the system by combined chemical-biological treatment

  9. Optical and thermal properties in ultrafast laser surface nanostructuring on biodegradable polymer

    Science.gov (United States)

    Yada, Shuhei; Terakawa, Mitsuhiro

    2015-03-01

    We investigate the effect of optical and thermal properties in laser-induced periodic surface structures (LIPSS) formation on a poly-L-lactic acid (PLLA), a biodegradable polymer. Surface properties of biomaterials are known to be one of the key factors in tissue engineering. Methods to process biomaterial surfaces have been studied widely to enhance cell adhesive and anisotropic properties. LIPSS formation has advantages in a dry processing which is able to process complex-shaped surfaces without using a toxic chemical component. LIPSS, however, was difficult to be formed on PLLA due to its thermal and optical properties compared to other polymers. To obtain new perspectives in effect of these properties above, LIPSS formation dependences on wavelength, pulse duration and repetition rate have been studied. At 800 nm of incident wavelength, high-spatial frequency LIPSS (HSFL) was formed after applying 10000 femtosecond pulses at 1.0 J/cm2 in laser fluence. At 400 nm of the wavelength, HSFL was formed at fluences higher than 0.20 J/cm2 with more than 3000 pulses. Since LIPSS was less formed with lower repetition rate, certain heat accumulation may be required for LIPSS formation. With the pulse duration of 2.0 ps, higher laser fluence as well as number of pulses compared to the case of 120 fs was necessary. This indicates that multiphoton absorption process is essential for LIPSS formation. Study on biodegradation modification was also performed.

  10. Delivery Device and Method for Forming the Same

    Science.gov (United States)

    Ma, Peter X. (Inventor); Liu, Xiaohua (Inventor); McCauley, Laurie (Inventor)

    2014-01-01

    A delivery device includes a hollow container, and a plurality of biodegradable and/or erodible polymeric layers established in the container. A layer including a predetermined substance is established between each of the plurality of polymeric layers, whereby degradation of the polymeric layer and release of the predetermined substance occur intermittently. Methods for forming the device are also disclosed herein.

  11. Anisotropic biodegradable lipid coated particles for spatially dynamic protein presentation.

    Science.gov (United States)

    Meyer, Randall A; Mathew, Mohit P; Ben-Akiva, Elana; Sunshine, Joel C; Shmueli, Ron B; Ren, Qiuyin; Yarema, Kevin J; Green, Jordan J

    2018-05-01

    There has been growing interest in the use of particles coated with lipids for applications ranging from drug delivery, gene delivery, and diagnostic imaging to immunoengineering. To date, almost all particles with lipid coatings have been spherical despite emerging evidence that non-spherical shapes can provide important advantages including reduced non-specific elimination and increased target-specific binding. We combine control of core particle geometry with control of particle surface functionality by developing anisotropic, biodegradable ellipsoidal particles with lipid coatings. We demonstrate that these lipid coated ellipsoidal particles maintain advantageous properties of lipid polymer hybrid particles, such as the ability for modular protein conjugation to the particle surface using versatile bioorthogonal ligation reactions. In addition, they exhibit biomimetic membrane fluidity and demonstrate lateral diffusive properties characteristic of natural membrane proteins. These ellipsoidal particles simultaneously provide benefits of non-spherical particles in terms of stability and resistance to non-specific phagocytosis by macrophages as well as enhanced targeted binding. These biomaterials provide a novel and flexible platform for numerous biomedical applications. The research reported here documents the ability of non-spherical polymeric particles to be coated with lipids to form anisotropic biomimetic particles. In addition, we demonstrate that these lipid-coated biodegradable polymeric particles can be conjugated to a wide variety of biological molecules in a "click-like" fashion. This is of interest due to the multiple types of cellular mimicry enabled by this biomaterial based technology. These features include mimicry of the highly anisotropic shape exhibited by cells, surface presentation of membrane bound protein mimetics, and lateral diffusivity of membrane bound substrates comparable to that of a plasma membrane. This platform is demonstrated to

  12. Vectorization of copper complexes via biocompatible and biodegradable PLGA nanoparticles.

    Science.gov (United States)

    Courant, T; Roullin, V G; Cadiou, C; Delavoie, F; Molinari, M; Andry, M C; Gafa, V; Chuburu, F

    2010-04-23

    A double emulsion-solvent diffusion approach with fully biocompatible materials was used to encapsulate copper complexes within biodegradable nanoparticles, for which the release kinetics profiles have highlighted their potential use for a prolonged circulating administration.

  13. 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.

  14. Biodegradation Potential of Oil-based Drill Cuttings Encapsulated ...

    African Journals Online (AJOL)

    Michael Horsfall

    significant attention has been turned toward encouraging ... impact indicators for biodegradation of wastes and environmental assessment (Videla, 1996; Godley. 2003; Stein ... Nitrate and sulphate concentration of samples was determined.

  15. Microbial biodegradable potato starch based low density polyethylene

    African Journals Online (AJOL)

    USER

    2010-06-28

    Jun 28, 2010 ... Key words: Low density polyethylene, fungi, biodegradable polymer, Pseudomonas aeruginosa. ... particle such as CO2 or water by microorganism's activities. ... package and production of bags, composites and agricultural.

  16. Biodegradation of waste PET based copolyesters in thermophilic anaerobic sludge

    Czech Academy of Sciences Publication Activity Database

    Hermanová, S.; Šmejkalová, P.; Merna, J.; Zarevúcka, Marie

    2015-01-01

    Roč. 111, Jan (2015), s. 176-184 ISSN 0141-3910 Institutional support: RVO:61388963 Keywords : poly(ethylene terephthalate) * copolymers * sludge * biodegradation * hydrolysis * waste Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.120, year: 2015

  17. 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)

  18. Biodegradation and bioresorption of poly(-caprolactone) nanocomposite scaffolds

    CSIR Research Space (South Africa)

    Mkhabela, V

    2015-08-01

    Full Text Available confirmed the elemental composition of the scaffolds. The phase composition of the scaffolds was shown by XRD, which also indicated a decrease in crystallinity with the introduction of nanoclay. Biodegradability studies which were conducted in simulated...

  19. 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.

  20. 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)

  1. Vectorization of copper complexes via biocompatible and biodegradable PLGA nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Courant, T; Roullin, V G; Andry, M C [Institut de Chimie Moleculaire de Reims, CNRS UMR 6229, UFR Pharmacie Reims, 51 rue Cognacq-Jay, F-51100 Reims (France); Cadiou, C; Chuburu, F [Institut de Chimie Moleculaire de Reims, CNRS UMR 6229, UFR des Sciences Exactes et Naturelles, Batiment 18-Europol' Agro, BP 1039, F-51687 Reims Cedex 2 (France); Delavoie, F [Laboratoire de Microscopie Electronique Analytique, INSERM UMRS 926, 21 rue Clement Ader, F-51685 Reims Cedex 2 (France); Molinari, M [Laboratoire de Microscopies et d' Etudes des Nanostructures, UFR des Sciences, Universite de Reims Champagne-Ardenne, 21 rue Clement Ader, F-51685 Reims Cedex 2 (France); Gafa, V, E-mail: gaelle.roullin@univ-reims.fr, E-mail: francoise.chuburu@univ-reims.fr [EA4303 ' Inflammation et Immunite de l' Epithelium Respiratoire' , IFR53, UFR de Pharmacie, Universite de Reims Champagne-Ardenne, 51 rue Cognacq-Jay, F-51100 Reims (France)

    2010-04-23

    A double emulsion-solvent diffusion approach with fully biocompatible materials was used to encapsulate copper complexes within biodegradable nanoparticles, for which the release kinetics profiles have highlighted their potential use for a prolonged circulating administration.

  2. Mechanical strength and stiffness of biodegradable and titanium osteofixation systems

    NARCIS (Netherlands)

    Buijs, Gerrit J.; van der Houwen, Eduard B.; Bos, Rudulf R. M.; Verkerke, Gijsbertus J.

    Purpose: To present relevant mechanical data to simplify the selection of an osteofixation system for situations requiring immobilization in oral and maxillofacial surgery. Materials and Methods: Seven biodegradable and 2 titanium osteofixation systems were investigated. The plates and screws were

  3. 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.

  4. 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 ...

  5. Base Oils Biodegradability Prediction with Data Mining Techniques

    Directory of Open Access Journals (Sweden)

    Malika Trabelsi

    2010-02-01

    Full Text Available In this paper, we apply various data mining techniques including continuous numeric and discrete classification prediction models of base oils biodegradability, with emphasis on improving prediction accuracy. The results show that highly biodegradable oils can be better predicted through numeric models. In contrast, classification models did not uncover a similar dichotomy. With the exception of Memory Based Reasoning and Decision Trees, tested classification techniques achieved high classification prediction. However, the technique of Decision Trees helped uncover the most significant predictors. A simple classification rule derived based on this predictor resulted in good classification accuracy. The application of this rule enables efficient classification of base oils into either low or high biodegradability classes with high accuracy. For the latter, a higher precision biodegradability prediction can be obtained using continuous modeling techniques.

  6. Fluorene biodegradation potentials of Bacillus strains isolated from ...

    African Journals Online (AJOL)

    Fluorene biodegradation potentials of Bacillus strains isolated from tropical ... Bacillus strains, putatively identified as Bacillus subtilis BM1 and Bacillus amyloliquefaciens BR1 were ... African Journal of Biotechnology, Vol 13(14), 1554-1559 ...

  7. Biodegradation of detergents by aquatic bacterial flora from Otamiri ...

    African Journals Online (AJOL)

    SERVER

    2008-03-18

    Mar 18, 2008 ... Full Length Research Paper. Biodegradation of detergents by ... releases toxins and decreases oxygen in waterways and decrease in the breeding ... of chemicals to microbial degradation and simulation test, which provide ...

  8. 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 ...

  9. 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-.

  10. Vectorization of copper complexes via biocompatible and biodegradable PLGA nanoparticles

    International Nuclear Information System (INIS)

    Courant, T; Roullin, V G; Andry, M C; Cadiou, C; Chuburu, F; Delavoie, F; Molinari, M; Gafa, V

    2010-01-01

    A double emulsion-solvent diffusion approach with fully biocompatible materials was used to encapsulate copper complexes within biodegradable nanoparticles, for which the release kinetics profiles have highlighted their potential use for a prolonged circulating administration.

  11. 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

  12. Enhancement of aerobic biodegradation in an oxygen-limiting environment using a saponin-based microbubble suspension

    International Nuclear Information System (INIS)

    Choi, Yong Ju; Kim, Young-Jin; Nam, Kyoungphile

    2009-01-01

    This study investigated the ability of a saponin-based microbubble suspension to enhance aerobic biodegradation of phenanthrene by subsurface delivery. As the microbubble suspension flowed through a sand column pressure buildup and release was repeatedly observed, which delivered oxygen to the less permeable regions. Burkholderia cepacia RPH1, a phenanthrene-degrading bacterium, was mainly transported in a suspended form in the microbubble suspension. When three pore volumes of the microbubble suspension containing B. cepacia RPH1 was introduced into a column contaminated with phenanthrene (100 mg/kg), the oxygen content declined to 5% from an initial value of 20% within 5 days and correspondingly, 34.4% of initial phenanthrene was removed in 8 days. The addition of two further three pore volumes enhanced the biodegradation efficiency by a factor of 2.2. Our data suggest that a saponin-based microbubble suspension could be a potential carrier for enhancing the aerobic biodegradation under an oxygen-limiting environment. - Microbubble suspension can enhance the phenanthrene biodegradation under an oxygen-limiting condition.

  13. Enhancement of aerobic biodegradation in an oxygen-limiting environment using a saponin-based microbubble suspension

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong Ju; Kim, Young-Jin [Department of Civil and Environmental Engineering, Seoul National University, Shillim-dong, Gwanak-gu, Seoul (Korea, Republic of); Nam, Kyoungphile, E-mail: kpnam@snu.ac.k [Department of Civil and Environmental Engineering, Seoul National University, Shillim-dong, Gwanak-gu, Seoul (Korea, Republic of)

    2009-08-15

    This study investigated the ability of a saponin-based microbubble suspension to enhance aerobic biodegradation of phenanthrene by subsurface delivery. As the microbubble suspension flowed through a sand column pressure buildup and release was repeatedly observed, which delivered oxygen to the less permeable regions. Burkholderia cepacia RPH1, a phenanthrene-degrading bacterium, was mainly transported in a suspended form in the microbubble suspension. When three pore volumes of the microbubble suspension containing B. cepacia RPH1 was introduced into a column contaminated with phenanthrene (100 mg/kg), the oxygen content declined to 5% from an initial value of 20% within 5 days and correspondingly, 34.4% of initial phenanthrene was removed in 8 days. The addition of two further three pore volumes enhanced the biodegradation efficiency by a factor of 2.2. Our data suggest that a saponin-based microbubble suspension could be a potential carrier for enhancing the aerobic biodegradation under an oxygen-limiting environment. - Microbubble suspension can enhance the phenanthrene biodegradation under an oxygen-limiting condition.

  14. 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.

  15. The prospects of biodegradable magnesium-based alloys in osteosynthesis

    Directory of Open Access Journals (Sweden)

    V. N. Chorny

    2013-12-01

    Full Text Available In the analytical review of the literature the main stages of development of biodegradable magnesium alloys in surgery and traumatology were discussed. The analysis revealed the main problems: there is no way to control the speed of the biological resorption alloys, the effects of products of magnesium degradation on the tissues and the organism in general are not studied, there is no information on the characteristics of the regeneration of bone tissue when implanted magnesium implanted magnesium alloys Materials for osteosynthesis with metal clamps made of steel X18H9T are used in 25,0-52,2% of cases, the corrosion of fasteners reaches 18-21%. Corrosion of the metal clips leads to the increase of the concentration of iron, chromium, nickel and titanium in the surrounding tissue. Electrochemical processes in metallic implants occurs due to their structural and chemical inhomogeneous. The microstructure of stainless steel is presented by differently oriented grains. Therefore, the question remains relevant to finding biodegradable materials suitable for implants for osteosynthesis, which could be completely metabolized by the organism, without causing of the pathological effects on the surrounding tissue and the body. The property of magnesium metal dissolved in the tissues of a living organism is known since the 19th century. Payr suggested the use of magnesium metal needles for the treatment of angiomas, in order to achieve thrombosis surrounding the tumor. In 1937 Lambotte made a post in the French Surgical Academy on the application of the osteosynthesis of the shin bone clamps with alloy Dow-metal (magnesium - 92% Aluminum - 8% + traces of manganese, made in the form of loops and screws. In 1938, Earl D. Mc.Braid and published their positive experience with plates and screws made of material similar in composition to the Dow-metal for osteosynthesis of fractures of the arm and forearm bones. Magnesium alloys may be used as a material for

  16. Fixation of zygomatic and mandibular fractures with biodegradable plates

    OpenAIRE

    Degala, Saikrishna; Shetty, Sujeeth; Ramya, S

    2013-01-01

    Context: 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. Aims: To assess the fixation of zygomatic-complex and mandibular fractures with biodegradable copolymer osteosynthesis system. Materials and Methods: In randomly selected 13 patients, zygomatic-complex and mandibular fractures were plated using resorbable plates and sc...

  17. 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...

  18. Evaluation of Biosolids for Use in Biodegradable Transplant Containers

    OpenAIRE

    Stone, Peyton Franklin

    2017-01-01

    Sustainability practices are leading to the development and use of alternative products in the floriculture and wastewater industries, such as the use of biodegradable containers instead of plastic containers. The objective of this research was to evaluate the efficacy of using digested biosolids from a regional wastewater treatment plant as an ingredient in creating a biodegradable transplant biocontainer. The biosolids were tested for metals limits as specified by the U.S. EPA Part 503 Rule...

  19. 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.

  20. Biodegradation of the High Explosive Hexanitrohexaazaiso-wurtzitane (CL-20)

    OpenAIRE

    Karakaya, Pelin; Christodoulatos, Christos; Koutsospyros, Agamemnon; Balas, Wendy; Nicolich, Steve; Sidhoum, Mohammed

    2009-01-01

    The aerobic biodegradability of the high explosive CL-20 by activated sludge and the white rot fungus Phanerochaete chrysosporium has been investigated. Although activated sludge is not effective in degrading CL-20 directly, it can mineralize the alkaline hydrolysis products. Phanerochaete chrysosporium degrades CL-20 in the presence of supplementary carbon and nitrogen sources. Biodegradation studies were conducted using various nutrient media under diverse conditions. Variables included the...

  1. Removal of Textile Dyestufes From Wastewater by Adsorptive Biodegradation

    OpenAIRE

    KAPDAN, İlgi KARAPINAR; KARGI, Fikret

    2000-01-01

    Removal of dyestuffs from a synthetic wastewater by adsorptive biodegradation was investigated in this study. The dyestuff adsorption capacities of granular, powdered activated carbon (GAC and PAC) and low-cost adsorbents such as zeolite, wood chips and wood ash were evaluated in order to obtain a low-cost adsorbent for use in an activated sludge unit. Then various activated sludge cultures were tested for biodegradation of a selected dyestuff. An activated sludge unit with the selected activ...

  2. Fully Biodegradable Biocomposites with High Chicken Feather Content

    OpenAIRE

    Aranberri, Ibon; Montes, Sarah; Azcune, Itxaso; Rekondo, Alaitz; Grande, Hans-Jürgen

    2017-01-01

    The aim of this work was to develop new biodegradable polymeric materials with high loadings of chicken feather (CF). In this study, the effect of CF concentration and the type of biodegradable matrix on the physical, mechanical and thermal properties of the biocomposites was investigated. The selected biopolymers were polylactic acid (PLA), polybutyrate adipate terephthalate (PBAT) and a PLA/thermoplastic copolyester blend. The studied biocomposites were manufactured with a to...

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. Using Biowin, Bayes, and batteries to predict ready biodegradability.

    Science.gov (United States)

    Boethling, Robert S; Lynch, David G; Jaworska, Joanna S; Tunkel, Jay L; Thom, Gary C; Webb, Simon

    2004-04-01

    Whether or not a given chemical substance is readily biodegradable is an important piece of information in risk screening for both new and existing chemicals. Despite the relatively low cost of Organization for Economic Cooperation and Development tests, data are often unavailable and biodegradability must be estimated. In this paper, we focus on the predictive value of selected Biowin models and model batteries using Bayesian analysis. Posterior probabilities, calculated based on performance with the model training sets using Bayes' theorem, were closely matched by actual performance with an expanded set of 374 premanufacture notice (PMN) substances. Further analysis suggested that a simple battery consisting of Biowin3 (survey ultimate biodegradation model) and Biowin5 (Ministry of International Trade and Industry [MITI] linear model) would have enhanced predictive power in comparison to individual models. Application of the battery to PMN substances showed that performance matched expectation. This approach significantly reduced both false positives for ready biodegradability and the overall misclassification rate. Similar results were obtained for a set of 63 pharmaceuticals using a battery consisting of Biowin3 and Biowin6 (MITI nonlinear model). Biodegradation data for PMNs tested in multiple ready tests or both inherent and ready biodegradation tests yielded additional insights that may be useful in risk screening.

  8. Bioavailability and biodegradation kinetics of organics in soil

    International Nuclear Information System (INIS)

    Tabak, H.H.; Govind, R.; Gao, Chao; Kim, In-soo; Lai, Lei

    1992-01-01

    As EPA begins to remediate Superfund sites using permanent treatment technologies, such as bioremediation, a fundamental understanding of the kinetics and the factors that control the rate of bioremediation will be required. Biological treatment technologies hold considerable promise for safe, economical, on-site treatment of toxic wastes. A variety of biological treatment systems designed to degrade or detoxify environmental contaminants are currently being developed and marketed. Knowledge of the kinetics of biodegradation is essential to the evaluation of the persistence of most organic pollutants in soil. Furthermore, measurement of biodegradation kinetics can provide useful insights into the favorable range of the important environmental parameters for improvement of the microbiological activity and consequently the enhancement of contaminant biodegradation. A major effort is currently underway to clean up aquifers and soils that are contaminated by organic chemicals, which has generated increased interest in the development of in situ bioremediation technologies. Although considerable data exists for rates of biodegradation in aquatic environments, there is little information on biodegradation kinetics in soil matrices, where irreversible binding to the soil phase may limit the chemicals bioavailability and ultimate degradation. Knowledge on biodegradation kinetics in soil environments can facilitate decisions on the efficacy of in situ bioremediation. 6 refs., 3 figs., 2 tabs

  9. Biodegradable polymers for targeted delivery of anti-cancer drugs.

    Science.gov (United States)

    Doppalapudi, Sindhu; Jain, Anjali; Domb, Abraham J; Khan, Wahid

    2016-06-01

    Biodegradable polymers have been used for more than three decades in cancer treatment and have received increased interest in recent years. A range of biodegradable polymeric drug delivery systems designed for localized and systemic administration of therapeutic agents as well as tumor-targeting macromolecules has entered into the clinical phase of development, indicating the significance of biodegradable polymers in cancer therapy. This review elaborates upon applications of biodegradable polymers in the delivery and targeting of anti-cancer agents. Design of various drug delivery systems based on biodegradable polymers has been described. Moreover, the indication of polymers in the targeted delivery of chemotherapeutic drugs via passive, active targeting, and localized drug delivery are also covered. Biodegradable polymer-based drug delivery systems have the potential to deliver the payload to the target and can enhance drug availability at desired sites. Systemic toxicity and serious side effects observed with conventional cancer therapeutics can be significantly reduced with targeted polymeric systems. Still, there are many challenges that need to be met with respect to the degradation kinetics of the system, diffusion of drug payload within solid tumors, targeting tumoral tissue and tumor heterogeneity.

  10. Biodegradation of tributyl phosphate by granular biofilms

    International Nuclear Information System (INIS)

    Joshi, Hiren M.; Nancharaiah, Y.V.; Venugopalan, V.P.

    2009-01-01

    Full text: Tributyl phosphate (TBP) is used as plasticizer for cellulose esters, lacquers, plastic and vinyl resins and as a solvent extractant of rare earth metals. In nuclear power industry, it is used as a solvent for the extraction of uranium and plutonium salts during fuel reprocessing. TBP does not occur naturally in the environment. It is sparingly soluble in water and once released into soil or aquatic systems, is only moderately biodegradable. There are many proposed mechanisms for TBP biodegradation, which involve stepwise enzymatic hydrolysis to orthophosphate and n-butanol and mono-oxygenase based transformation and then degradation. Microbial processes involving multispecies consortia offer better choice over monoculture processes for degradation of complex wastes. Processes based on immobilized microbial consortia are characterized by significantly reduced settling time, high stability in presence of varying organic load, effective mineralization and amenability to bioaugmentation, which make them a good choice for bioremediation and waste water treatment. The objective of this study was to investigate the suitability of aerobic microbial granules (also known as granular biofilms) for efficient biodegradation of TBP. For this purpose, we set up 4 litre cylindrical sequencing batch reactors (SBR) in triplicates and inoculated them with sludge (mean sludge size ∼ 60 mm) obtained from an operating wastewater treatment plant. The SBRs were operated on a 6h cycle with 66% volumetric exchange ratio. The reactors were fed with synthetic waste water along with 90 mM acetate and 0.5 mM TBP. The concentration of TBP was slowly raised to 2mM. After 3 months of operation, microbial granules (mean size: 2.05 mm) capable of TBP degradation were observed in the reactors. Gas chromatographic analysis of samples showed that after 6h of operational cycle 2 mM initial concentration of TBP was reduced to 0.2 mM, after which there was no further degradation. Cessation

  11. Moessbauer spectroscopy for characterizing biodegradation of magnetic nanoparticles in a living organism

    Energy Technology Data Exchange (ETDEWEB)

    Mischenko, Ilya Nikitich, E-mail: IlyaMischenko@rambler.ru; Chuev, Michail Alexandrovich; Cherepanov, Valeriy Mihailovich; Polikarpov, Michail Alexeevich [National Research Centre ' Kurchatov Institute' (Russian Federation)

    2012-03-15

    We have developed a model for describing nanoparticles magnetic dynamics. This allows us to fit self-consistently the wide set of the experimental data, particularly, the evolution of Moessbauer spectral shape with temperature and external magnetic field as well as the magnetization curves for nanoparticles injected into mice. Thus, we reliably evaluate changes in characteristics of the nanoparticles and their chemical transformation to ferritin-like forms in mouse's organs as a function of time after injection of nanoparticles. Actually, the approach allows one to quantitatively characterize biodegradation and biotransformation of magnetic particles in a body.

  12. Mössbauer spectroscopy for characterizing biodegradation of magnetic nanoparticles in a living organism

    International Nuclear Information System (INIS)

    Mischenko, Ilya Nikitich; Chuev, Michail Alexandrovich; Cherepanov, Valeriy Mihailovich; Polikarpov, Michail Alexeevich

    2012-01-01

    We have developed a model for describing nanoparticles magnetic dynamics. This allows us to fit self-consistently the wide set of the experimental data, particularly, the evolution of Mössbauer spectral shape with temperature and external magnetic field as well as the magnetization curves for nanoparticles injected into mice. Thus, we reliably evaluate changes in characteristics of the nanoparticles and their chemical transformation to ferritin-like forms in mouse’s organs as a function of time after injection of nanoparticles. Actually, the approach allows one to quantitatively characterize biodegradation and biotransformation of magnetic particles in a body.

  13. 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.

  14. Melt electrospinning of biodegradable polyurethane scaffolds

    Science.gov (United States)

    Karchin, Ari; Simonovsky, Felix I.; Ratner, Buddy D.; Sanders, Joan E.

    2014-01-01

    Electrospinning from the melt, in contrast to from solution, is an attractive tissue engineering scaffold manufacturing process as it allows for the formation of small diameter fibers while eliminating potentially cytotoxic solvents. Despite this, there is a dearth of literature on scaffold formation via melt electrospinning. This is likely due to the technical challenges related to the need for a well-controlled high temperature setup and the difficulty in developing an appropriate polymer. In this paper, a biodegradable and thermally stable polyurethane (PU) is described specifically for use in melt electrospinning. Polymer formulations of aliphatic PUs based on (CH2)4-content diisocyanates, polycaprolactone (PCL), 1,4-butanediamine and 1,4-butanediol (BD) were evaluated for utility in the melt electrospinning process. The final polymer formulation, a catalyst-purified PU based on 1,4-butane diisocyanate, PCL and BD in a 4/1/3 molar ratio with a weight-average molecular weight of about 40 kDa, yielded a nontoxic polymer that could be readily electrospun from the melt. Scaffolds electrospun from this polymer contained point bonds between fibers and mechanical properties analogous to many in vivo soft tissues. PMID:21640853

  15. Biodegradation of chlorpyrifos by bacterial genus Pseudomonas.

    Science.gov (United States)

    Gilani, Razia Alam; Rafique, Mazhar; Rehman, Abdul; Munis, Muhammad Farooq Hussain; Rehman, Shafiq Ur; Chaudhary, Hassan Javed

    2016-02-01

    Chlorpyrifos is an organophosphorus pesticide commonly used in agriculture. It is noxious to a variety of organisms that include living soil biota along with beneficial arthropods, fish, birds, humans, animals, and plants. Exposure to chlorpyrifos may cause detrimental effects as delayed seedling emergence, fruit deformities, and abnormal cell division. Contamination of chlorpyrifos has been found about 24 km from the site of its application. There are many physico-chemical and biological approaches to remove organophosphorus pesticides from the ecosystem, among them most promising is biodegradation. The 3,5,6-trichloro-2-pyridinol (TCP) and diethylthiophosphate (DETP) as primary products are made when chlorpyrifos is degraded by soil microorganisms which further break into nontoxic metabolites as CO(2), H(2)O, and NH(3). Pseudomonas is a diversified genus possessing a series of catabolic pathways and enzymes involved in pesticide degradation. Pseudomonas putida MAS-1 is reported to be more efficient in chlorpyrifos degradation by a rate of 90% in 24 h among Pseudomonas genus. The current review analyzed the comparative potential of bacterial species in Pseudomonas genus for degradation of chlorpyrifos thus, expressing an ecofriendly approach for the treatment of environmental contaminants like pesticides. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Microbial ecology of bacterially mediated PCB biodegradation

    International Nuclear Information System (INIS)

    Pettigrew, C.A. Jr.

    1989-01-01

    The roles of plasmid mediated and consortia mediated polychlorinated biphenyl (PCB) biodegradation by bacterial populations isolated from PCB contaminated freshwater sediments were investigated. PCB degrading bacteria were isolated by DNA:DNA colony hybridization, batch enrichments, and chemostat enrichment. Analysis of substrate removal and metabolite production were done using chlorinated biphenyl spray plates, reverse phase high pressure liquid chromatography, Cl - detection, and 14 C-labeled substrate mineralization methods. A bacterial consortium, designated LPS10, involved in a concerted metabolic attack on chlorinated biphenyls, was shown to mineralize 4-chlorobiphenyl (4CB) and 4,4'-dichlorobiphenyl (4,4' CB). The LPS10 consortium was isolated by both batch and chemostat enrichment using 4CB and biphenyl (BP) as sole carbon source and was found to have tree bacterial isolates that predominated; these included: Pseudomonas, testosteroni LPS10A which mediated the breakdown of 4CB and 4,4' CB to the putative meta-cleavage product and subsequently to 4-chlorobenzoic acid (4CBA), an isolate tentatively identified as an Arthrobacter sp. LPS10B which mediated 4CBA degradation, and Pseudomonas putida by A LPS10C whose role in the consortium has not been determined

  17. Biodegradable urethral stent in the treatment of post-traumatic urethral strictures in a war wound rabbit urethral model

    International Nuclear Information System (INIS)

    Fu Weijun; Zhang Binghong; Gao Jiangping; Hong Baofa; Zhang Lei; Yang Yong; Meng Bo; Zhu Ning; Cui Fuzhai

    2007-01-01

    To prevent terrorism during anti-terror war, we developed a reproducible animal model for the induction of a urethral stricture in a war wound rabbit, and to evaluate the feasibility and effect of using a biodegradable urethral stent in the prophylaxis and treatment of urethral strictures in a war wound (or traumatic) rabbit urethral model. The urethral stricture rabbit model was successfully performed by a self-control explosion destructor. New biodegradable urethral stents were placed in the urethras of 20 war wound (traumatic) rabbits, but no stent was used in the 8 rabbits which formed the control group. Follow-up investigation included assessment of procedure success, stent changes, urethrascopy and retrograde urethrography, and histological findings were obtained after sacrifice at 4, 6, 8 and 12 weeks after stent placement. The urethral stricture model owing to a war wound (trauma) was tested by tissue reactions and urethroscopy. The length of the urethral strictures was 5-10 mm; the coarctatetion of the urethral lumen was more than 50%. Biodegradable stent placement was technically successful in 20 rabbits. Urethral specimens obtained from the 4 week stent placement group showed diminished inflammatory cell infiltration and decreased thickness of the papillary projections of the epithelium. There was a strong tendency towards regression of the papillary projections and regeneration of urethral mucosa epithelium in the 8 week group. In particular, the injured urethra has recovered completely in the biodegradable stent groups compared with the control group at 12 weeks. The biodegradable urethral stent seems feasible for treating and preventing urethral strictures owing to a war wound (or traumatic) urethra. There are distinct advantages in terms of safe, effective and less-invasive treatment for the reconstruction of post-traumatic urethral strictures

  18. Biodegradable urethral stent in the treatment of post-traumatic urethral strictures in a war wound rabbit urethral model

    Energy Technology Data Exchange (ETDEWEB)

    Fu Weijun [Department of Urology, Chinese People' s Liberation Army General Hospital, Military Postgraduate Medical College, No.28 Fuxing Road, Hai dian District, Beijing 100853 (China); Zhang Binghong [Department of Urology, Chinese People' s Liberation Army General Hospital, Military Postgraduate Medical College, No.28 Fuxing Road, Hai dian District, Beijing 100853 (China); Gao Jiangping [Department of Urology, Chinese People' s Liberation Army General Hospital, Military Postgraduate Medical College, No.28 Fuxing Road, Hai dian District, Beijing 100853 (China); Hong Baofa [Department of Urology, Chinese People' s Liberation Army General Hospital, Military Postgraduate Medical College, No.28 Fuxing Road, Hai dian District, Beijing 100853 (China); Zhang Lei [Department of Urology, Chinese People' s Liberation Army General Hospital, Military Postgraduate Medical College, No.28 Fuxing Road, Hai dian District, Beijing 100853 (China); Yang Yong [Department of Urology, Chinese People' s Liberation Army General Hospital, Military Postgraduate Medical College, No.28 Fuxing Road, Hai dian District, Beijing 100853 (China); Meng Bo [Biomaterials Lab, School of Materials Science and Engineering, Tsinghua University, Beijing (China); Zhu Ning [Biomaterials Lab, School of Materials Science and Engineering, Tsinghua University, Beijing (China); Cui Fuzhai [Biomaterials Lab, School of Materials Science and Engineering, Tsinghua University, Beijing (China)

    2007-12-15

    To prevent terrorism during anti-terror war, we developed a reproducible animal model for the induction of a urethral stricture in a war wound rabbit, and to evaluate the feasibility and effect of using a biodegradable urethral stent in the prophylaxis and treatment of urethral strictures in a war wound (or traumatic) rabbit urethral model. The urethral stricture rabbit model was successfully performed by a self-control explosion destructor. New biodegradable urethral stents were placed in the urethras of 20 war wound (traumatic) rabbits, but no stent was used in the 8 rabbits which formed the control group. Follow-up investigation included assessment of procedure success, stent changes, urethrascopy and retrograde urethrography, and histological findings were obtained after sacrifice at 4, 6, 8 and 12 weeks after stent placement. The urethral stricture model owing to a war wound (trauma) was tested by tissue reactions and urethroscopy. The length of the urethral strictures was 5-10 mm; the coarctatetion of the urethral lumen was more than 50%. Biodegradable stent placement was technically successful in 20 rabbits. Urethral specimens obtained from the 4 week stent placement group showed diminished inflammatory cell infiltration and decreased thickness of the papillary projections of the epithelium. There was a strong tendency towards regression of the papillary projections and regeneration of urethral mucosa epithelium in the 8 week group. In particular, the injured urethra has recovered completely in the biodegradable stent groups compared with the control group at 12 weeks. The biodegradable urethral stent seems feasible for treating and preventing urethral strictures owing to a war wound (or traumatic) urethra. There are distinct advantages in terms of safe, effective and less-invasive treatment for the reconstruction of post-traumatic urethral strictures.

  19. Co-optimization of diesel fuel biodegradation and N2 fixation through the addition of particulate organic carbon

    International Nuclear Information System (INIS)

    Piehler, M.; Swistak, J.; Paerl, H.

    1995-01-01

    Petroleum hydrocarbon pollution in the marine environment is widespread and current bioremedial techniques are often not cost effective for small spills. The formulation of simple and inexpensive bioremedial methods could help reduce the impacts of frequent low volume spills in areas like marinas and ports. Particulate organic carbon (POC) was added to diesel fuel amended samples from inshore marine waters in the form of corn-slash (post-harvest leaves and stems), with and without inorganic nutrients (nitrate and phosphate). Biodegradation of diesel fuel ( 14 C hexadecane mineralization) and N 2 fixation were measured in response to the additions, The addition of POC was necessary for N 2 fixation and diesel fuel biodegradation to co-occur. The effects of diesel fuel and inorganic nutrient additions on N 2 fixation rates were not consistent, with both inhibitory and stimulatory responses to each addition observed. The highest observed diesel fuel biodegradation levels were in response to treatments that included inorganic nutrients. The addition of POC alone increased diesel fuel degradation levels above that observed in the control. In an attempt to determine the effect of the POC on the microbial community, the corn particles were observed microscopically using scanning electron microscopy and light microscopy with tetrazolium salt additions. The corn particles were found to have abundant attached bacterial communities and microscale oxygen concentration gradients occurring on individual particles. The formation of oxygen replete microzones may be essential for the co-occurrence of aerobic diesel fuel biodegradation and oxygen inhibited N2 fixation. Mesocosm experiments are currently underway to further examine the structure and function of this primarily heterotrophic system and to explore the potential contribution of N 2 fixation to the N requirements of diesel fuel biodegradation

  20. Sorption and biodegradation of sulfonamide antibiotics by activated sludge: experimental assessment using batch data obtained under aerobic conditions.

    Science.gov (United States)

    Yang, Sheng-Fu; Lin, Cheng-Fang; Lin, Angela Yu-Chen; Hong, Pui-Kwan Andy

    2011-05-01

    This study investigated the adsorption, desorption, and biodegradation characteristics of sulfonamide antibiotics in the presence of activated sludge with and without being subjected to NaN(3) biocide. Batch experiments were conducted and the relative contributions of adsorption and biodegradation to the observed removal of sulfonamide antibiotics were determined. Three sulfonamide antibiotics including sulfamethoxazole (SMX), sulfadimethoxine (SDM), and sulfamonomethoxine (SMM), which had been detected in the influent and the activated sludge of wastewater treatment plants (WWTP) in Taiwan, were selected for this study. Experimental results showed that the antibiotic compounds were removed via sorption and biodegradation by the activated sludge, though biodegradation was inhibited in the first 12 h possibly due to competitive inhibition of xenobiotic oxidation by readily biodegradable substances. The affinity of sulfonamides to sterilized sludge was in the order of SDM > SMM > SMX. The sulfonamides existed predominantly as anions at the study pH of 6.8, which resulted in a low level of adsorption to the activated sludge. The adsorption/desorption isotherms were of a linear form, as well described by the Freundlich isotherm with the n value approximating unity. The linear distribution coefficients (K(d)) were determined from batch equilibrium experiments with values of 28.6 ± 1.9, 55.7 ± 2.2, and 110.0 ± 4.6 mL/g for SMX, SMM, and SDM, respectively. SMX, SMM, and SDM desorb reversibly from the activated sludge leaving behind on the solids 0.9%, 1.6%, and 5.2% of the original sorption dose of 100 μg/L. The sorbed antibiotics can be introduced into the environment if no further treatments were employed to remove them from the biomass. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Photolysis of sulfamethoxypyridazine in various aqueous media: Aerobic biodegradation and identification of photoproducts by LC-UV–MS/MS

    Energy Technology Data Exchange (ETDEWEB)

    Khaleel, Nareman D.H., E-mail: drndahshan@yahoo.com [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Leuphana University Lüneburg, C13, DE-21335 Lüneburg (Germany); Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Suez Canal University, Ismailia 41522 (Egypt); Mahmoud, Waleed M.M. [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Leuphana University Lüneburg, C13, DE-21335 Lüneburg (Germany); Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Suez Canal University, Ismailia 41522 (Egypt); Hadad, Ghada M.; Abdel-Salam, Randa A. [Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Suez Canal University, Ismailia 41522 (Egypt); Kümmerer, Klaus, E-mail: Klaus.Kuemmerer@uni.leuphana.de [Sustainable Chemistry and Material Resources, Institute of Sustainable and Environmental Chemistry, Leuphana University Lüneburg, C13, DE-21335 Lüneburg (Germany)

    2013-01-15

    Highlights: ► Sulfonamides are one of the most extensively used antibiotics in human and veterinary medicine. ► Sulfamethoxypyridazine (SMP) underwent photodegradation in three different media. ► SMP was not readily biodegradable. ► SMP and some of its degradation products were identified by LC-UV–MS/MS. -- Abstract: Sulfonamides are one of the most frequently used antibiotics worldwide. Therefore, mitigation processes such as abiotic or biotic degradation are of interest. Photodegradation and biodegradation are the potentially significant removal mechanisms for pharmaceuticals in aquatic environments. The photolysis of sulfamethoxypyridazine (SMP) using a medium pressure Hg-lamp was evaluated in three different media: Millipore water pH 6.1 (MW), effluent from sewage treatment plant pH 7.6 (STP), and buffered demineralized water pH 7.4 (BDW). Identification of transformation products (TPs) was performed by LC-UV–MS/MS. The biodegradation of SMP using two tests from the OECD series was studied: Closed Bottle test (OECD 301 D), and Manometric Respirometry test (OECD 301 F). In biodegradation tests, it was found that SMP was not readily biodegradable so it may pose a risk to the environment. The results showed that SMP was removed completely within 128 min of irradiation in the three media, and the degradation rate was different for each investigated type of water. However, dissolved organic carbon (DOC) was not removed in BDW and only little DOC removal was observed in MW and STP, thus indicating the formation of TPs. Analysis by LC-UV–MS/MS revealed new TPs formed. The hydroxylation of SMP represents the main photodegradation pathway.

  2. Photolysis of sulfamethoxypyridazine in various aqueous media: Aerobic biodegradation and identification of photoproducts by LC-UV–MS/MS

    International Nuclear Information System (INIS)

    Khaleel, Nareman D.H.; Mahmoud, Waleed M.M.; Hadad, Ghada M.; Abdel-Salam, Randa A.; Kümmerer, Klaus

    2013-01-01

    Highlights: ► Sulfonamides are one of the most extensively used antibiotics in human and veterinary medicine. ► Sulfamethoxypyridazine (SMP) underwent photodegradation in three different media. ► SMP was not readily biodegradable. ► SMP and some of its degradation products were identified by LC-UV–MS/MS. -- Abstract: Sulfonamides are one of the most frequently used antibiotics worldwide. Therefore, mitigation processes such as abiotic or biotic degradation are of interest. Photodegradation and biodegradation are the potentially significant removal mechanisms for pharmaceuticals in aquatic environments. The photolysis of sulfamethoxypyridazine (SMP) using a medium pressure Hg-lamp was evaluated in three different media: Millipore water pH 6.1 (MW), effluent from sewage treatment plant pH 7.6 (STP), and buffered demineralized water pH 7.4 (BDW). Identification of transformation products (TPs) was performed by LC-UV–MS/MS. The biodegradation of SMP using two tests from the OECD series was studied: Closed Bottle test (OECD 301 D), and Manometric Respirometry test (OECD 301 F). In biodegradation tests, it was found that SMP was not readily biodegradable so it may pose a risk to the environment. The results showed that SMP was removed completely within 128 min of irradiation in the three media, and the degradation rate was different for each investigated type of water. However, dissolved organic carbon (DOC) was not removed in BDW and only little DOC removal was observed in MW and STP, thus indicating the formation of TPs. Analysis by LC-UV–MS/MS revealed new TPs formed. The hydroxylation of SMP represents the main photodegradation pathway

  3. BIODEGRADATION OF DDT [1,1,1-TRICHLORO-2,2-BIS(4- CHLOROPHENYL) ETHANE] BY THE WHITE ROT FUNGUS PHANEROCHAETE CHRYSOSPORIUM

    Science.gov (United States)

    Extensive biodegradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) by the white rot fungus Phanerochaete chrysosporium was demonstrated by disappearance and mineralization of [14C]DDT in nutrient nitrogen-deficient cultures. Mass balance studies demonstrated the form...

  4. Ex vivo evaluation of biodegradable poly(ε-caprolactone) films in digestive fluids

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hao-Ming [Division of General Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei 100, Taiwan, ROC (China); Prasannan, Adhimoorthy [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan, ROC (China); Tsai, Hsieh-Chih, E-mail: h.c.tsai@mail.ntust.edu.tw [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan, ROC (China); Jhu, Jheng-Jun [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan, ROC (China)

    2014-09-15

    Graphical abstract: The biodegradable poly(ε-caprolactone) (PCL) films in several digestive glands using films formed from a solution of PCL in dichloromethane and ether. The PCL films degraded very differently in different digestive glands while they continued to undergo hydrolysis. - Highlights: • Hydrolytic and protein enzymatic degradation of PCL films were studied in terms of weight loss, and the degraded films were characterized using SEM, TGA, FTIR, and DSC. • Degradation of the PCL films in saliva and gastric juice was followed by superficial erosion, while the degradation of the PCL films immersed in bile and PBS was followed by bulk erosion. • For all degraded PCL films, degradation began in the amorphous regions of the films and the fraction of crystalline PCL increased slightly. - Abstract: Successful application of biodegradable implants in the gastrointestinal tract requires intensive research to understand their degradation behavior. We studied biodegradable poly(ε-caprolactone) (PCL) films in several digestive glands using films formed from a solution of PCL in dichloromethane and ether. Examination of the film morphology showed that solvent evaporation resulted in the formation of a smooth and flat surface. In addition, our results revealed that the PCL films degraded very differently in different digestive glands while they continued to undergo hydrolysis. There was also significant weight loss in the PCL films in saliva and gastric juice, which indicates that the degradation was sensitive to protein enzymes. Deconstruction of the PCL film was first discovered when it was incubated with saliva for 6 weeks. These results indicate that the degradation by saliva was mainly responsible for the enzymatic erosion of the film, which was confirmed by scanning electron microscopy.

  5. BIODEGRADATION DURING CONTAMINANT TRANSPORT IN POROUS MEDIA. 3. APPARENT CONDITION-DEPENDENCY OF GROWTH-RELATED COEFFICIENTS. (R825415)

    Science.gov (United States)

    AbstractThe biodegradation of organic contaminants in the subsurface has become a major focus of attention, in part, due to the tremendous interest in applying in situ biodegradation and natural attenuation approaches for site remediation. The biodegradation and trans...

  6. Effect of Commercial SiO2 and SiO2 from rice husk ash loading on biodegradation of Poly (lactic acid) and crosslinked Poly (lactic acid)

    Science.gov (United States)

    Prapruddivongs, C.; Apichartsitporn, M.; Wongpreedee, T.

    2017-09-01

    In this work, biodegradation behavior of poly (lactic acid) (PLA) and crosslinked PLA filled with two types of SiO2, precipitated SiO2 (commercial SiO2) and SiO2 from rice husk ash, were studied. Rice husks were first treated with 2 molar hydrochloric acid (HCl) to produce high purity SiO2, before burnt in a furnace at 800°C for 6 hours. All components were melted bending by an internal mixer then hot pressed using compression molder to form tested specimens. FTIR spectra of SiO2 and PLA samples were investigated. The results showed the lack of silanol group (Si-OH) of rice husk ash after steric acid surface modification, while the addition of particles can affect the crosslinking of the PLA. For biodegradation test by evaluating total amount of carbon dioxide (CO2) evolved during 60 days incubation at a controlled temperature of 58±2°C, the results showed that the biodegradation of crosslinked PLA occurred slower than the neat PLA. However, SiO2 incorporation enhanced the degree of biodegradation In particular, introducing commercial SiO2 in PLA and crosslinked PLA tended to clearly increase the degree of biodegradation as a consequence of the more accelerated hydrolysis degradation.

  7. Biodegradation of imidazolium ionic liquids by activated sludge microorganisms.

    Science.gov (United States)

    Liwarska-Bizukojc, Ewa; Maton, Cedric; Stevens, Christian V

    2015-11-01

    Biological properties of ionic liquids (ILs) have been usually tested with the help of standard biodegradation or ecotoxicity tests. So far, several articles on the identification of intermediate metabolites of microbiological decay of ILs have been published. Simultaneously, the number of novel ILs with unrecognized characteristics regarding biodegradability and effect on organisms and environment is still increasing. In this work, seven imidazolium ionic liquids of different chemical structure were studied. Three of them are 1-alkyl-3-methyl-imidazolium bromides, while the other four are tetra- or completely substituted imidazolium iodides. This study focused on the identification of intermediate metabolites of the aforementioned ionic liquids subjected to biodegradation in a laboratory activated sludge system. Both fully substituted ionic liquids and 1-ethyl-3-methyl-imidazolium bromide were barely biodegradable. In the case of two of them, no biotransformation products were detected. The elongation of the alkyl side chain made the IL more susceptible for microbiological decomposition. 1-Decyl-3-methyl-imidazolium bromide was biotransformed most easily. Its primary biodegradation up to 100 % could be achieved. Nevertheless, the cleavage of the imidazolium ring has not been observed.

  8. 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.

  9. 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.

  10. 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.

  11. Catechol biodegradation kinetics using Candida parapsilopsis

    Directory of Open Access Journals (Sweden)

    Maurício Rigo

    2010-04-01

    Full Text Available This study evaluated the biodegradation of catechol by a yeast strain of Candida parapsilopsis in standard medium in Erlenmeyer flasks. Results shown that the highest concentration of catechol caused the longer lag period, demonstrating that acclimatized cultures could completely degrade an initial catechol concentration of 910 mg/L within 48 h. Haldane's model validated the experimental data adequately for growth kinetics over the studied catechol concentration ranges of 36 to 910 mg/L. The constants obtained for this model were µmax = 0.246 h-1, Ks = 16.95 mg/L and Ki = 604.85 mg/L.Neste trabalho foi estudada a biodegradação de catecol em frascos de Erlenmeyers em água residuária sintética pela levedura Candida parapsilopsis. As respostas dos ensaios cinéticos mostraram que altas concentrações de catecol ocasionaram uma fase lag longa para a levedura. Portanto, a aclimatização da cultura de levedura empregada para biodegradação de catecol é de fundamental importância, sendo possível reduzir toda a concentração inicial de catecol da água residuária sintética de 910 mg/L em 48 horas. Os dados experimentais da cinética de biodegradação do catecol foram ajustados pelo modelo de Haldane adequadamente, sobre a faixa de concentração de catecol investigada de 36 a 910 mg/L. Os parâmetros cinéticos obtidos do modelo de Haldane foram: µmax = 0,246 h-1, Ks = 16,95 mg/L e Ki = 604,85 mg/L.

  12. Hydrolytic And Enzymatic Degradation Characteristics Of Biodegradable Aliphatic Polysters

    Institute of Scientific and Technical Information of China (English)

    LI Suming

    2004-01-01

    Aliphatic polyesters, especially those derived from lactide (PLA), glycolide (PGA) and ε-caprolactone (PCL), are being investigated worldwide for applications in the field of surgery (suture material, devices for internal bone fracture fixation), pharmacology (sustained drug delivery systems), and tissue engineering (scaffold for tissue regeneration) [1,2]. This is mainly due to their good biocompatibility and variable degradability. These polymers present also a growing interest for environmental applications in agriculture (mulch films) and in our everyday life (packaging material)as the development of biodegradable materials is now considered as one of the potential solutions to the problem of plastic waste management.For both biomedical and environmental applications, it is of major importance to understand the degradation characteristics of the polymers. The hydrolytic degradation of aliphatic polyesters has been investigated by many research groups. Our group has shown that degradation of PLAGA large size devices is faster inside than at the surface. This heterogeneous degradation is due to the autocatalytic effect of carboxylic endgroups formed by ester bond cleavage. Moreover,degradation-induced morphological and compositional changes were also elucidated. In the case of PCL, the hydrolytic degradation is very slow due to its hydrophobicity and crystallinity.The enzymatic degradation of these polymers has been investigated by a number of authors. A specific enzyme, proteinase K, has been shown to have significant effects on PLA degradation. This enzyme preferentially degrade L-lactate units as opposed to D-lactate ones, amorphous zones as opposed to crystalline ones [3]. The enzymatic degradation of PCL polymers has also been investigated. A number of lipase-type enzymes were found to significantly accelerate the degradation of PCL despite its high crystallinity. In the case of PLA/PCL blends, the two components exhibited well separated crystalline domains

  13. OxDBase: a database of oxygenases involved in biodegradation

    Directory of Open Access Journals (Sweden)

    Raghava Gajendra PS

    2009-04-01

    Full Text Available Abstract Background Oxygenases belong to the oxidoreductive group of enzymes (E.C. Class 1, which oxidize the substrates by transferring oxygen from molecular oxygen (O2 and utilize FAD/NADH/NADPH as the co-substrate. Oxygenases can further be grouped into two categories i.e. monooxygenases and dioxygenases on the basis of number of oxygen atoms used for oxidation. They play a key role in the metabolism of organic compounds by increasing their reactivity or water solubility or bringing about cleavage of the aromatic ring. Findings We compiled a database of biodegradative oxygenases (OxDBase which provides a compilation of the oxygenase data as sourced from primary literature in the form of web accessible database. There are two separate search engines for searching into the database i.e. mono and dioxygenases database respectively. Each enzyme entry contains its common name and synonym, reaction in which enzyme is involved, family and subfamily, structure and gene link and literature citation. The entries are also linked to several external database including BRENDA, KEGG, ENZYME and UM-BBD providing wide background information. At present the database contains information of over 235 oxygenases including both dioxygenases and monooxygenases. This database is freely available online at http://www.imtech.res.in/raghava/oxdbase/. Conclusion OxDBase is the first database that is dedicated only to oxygenases and provides comprehensive information about them. Due to the importance of the oxygenases in chemical synthesis of drug intermediates and oxidation of xenobiotic compounds, OxDBase database would be very useful tool in the field of synthetic chemistry as well as bioremediation.

  14. Biodegradation of an oily bilge waste using algae

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.J.

    1987-01-01

    A mixed community of microogranisms was collected from the harbor at the North Island Navy Base and was monitored in a test ecosystem containing an oily bilge waste obtained from off-loading ships. Cultures were examined in the presence and absence of the algae. It was thought that the algae might enhance the degradation of the oil waste by providing oxygen and possibly a nutrient source from dying phytoplankton for the bacterial community. The change in community structure was monitored by isolating the various groups of organisms and determining the biomass change over time for the algae, bacteria and yeasts/fungi subjected to the bilge waste. The biomass (i.e., colony forming units) of the yeasts and fungi increased 100 fold in a 6 week test period. The community containing only the bacteria and fungi/yeasts lost the fungal component of the population, although active bacteria biomass increased more than 10 fold during exposure to the waste. The test ecosystem was subjected to a radiolabeled compound (/sup 14/C-phenol) and bilge waste mixture to ascertain the ability of the communities to mineralize the phenol and/or assimilate the labeled hydrocarbon. The community containing the algae started mineralizing the phenol (measure by /sup 14/CO/sub 2/ production) 24 hours after exposure to the waste/phenol mixture. The bacteria/yeast-fungi community had a lag period of 384 hours before extensive catabolism of the labeled compound occurred. Current data indicate algae may enhance the biodegradation rate of oil bilge waste in a mixed microbial community.

  15. Effects of lag and maximum growth in contaminant transport and biodegradation modeling

    International Nuclear Information System (INIS)

    Wood, B.D.; Dawson, C.N.

    1992-06-01

    The effects of time lag and maximum microbial growth on biodegradation in contaminant transport are discussed. A mathematical model is formulated that accounts for these effects, and a numerical case study is presented that demonstrates how lag influences biodegradation

  16. Studies in reactive extrusion processing of biodegradable polymeric materials

    Science.gov (United States)

    Balakrishnan, Sunder

    Various reaction chemistries such as Polymerization, Polymer cross-linking and Reactive grafting were investigated in twin-screw extruders. Poly (1,4-dioxan-2-one) (PPDX) was manufactured in melt by the continuous polymerization of 1,4-dioxan-2-one (PDX) monomer in a twin-screw extruder using Aluminum tri-sec butoxide (ATSB) initiator. Good and accurate control over molecular weight was obtained by controlling the ratio of monomer to initiator. A screw configuration consisting of only conveying elements was used for the polymerization. The polymerization reaction was characterized by a monomer-polymer dynamic equilibrium, above the melting temperature of the polymer, limiting the equilibrium conversion to 78-percent. Near complete (˜100-percent) conversion was obtained on co-polymerizing PDX monomer with a few mol-percent (around 8-percent) Caprolactone (CL) monomer in a twin-screw extruder using ATSB initiator. The co-polymers exhibited improved thermal stability with reduction in glass transition temperature. The extruder was modeled as an Axial Dispersed Plug Flow Reactor for the polymerization of CL monomer using Residence Time Distribution (RTD) Analysis. The model provided a good fit to the experimental RTD and conversion data. Aliphatic and aliphatic-aromatic co-polyesters, namely Polycaprolactone (PCL) and Poly butylenes (adipate-co-terephthalate) (Ecoflex) were cross-linked in a twin-screw extruder using radical initiator to form micro-gel reinforced biodegradable polyesters. Cross-linked Ecoflex was further extrusion blended with talc to form blends suitable to be blown into films. A screw configuration consisting of conveying and kneading elements was found to be effective in dispersion of the talc particles (5--10 microns) in the polyester matrix. While the rates of crystallization increased for the talc filled polyester blends, overall crystallinity reduced. Mechanical, tear and puncture properties of films made using the talc filled polyester blends

  17. 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

  18. 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.

  19. The freshwater biodegradation potential of nine Alaskan oils

    International Nuclear Information System (INIS)

    Blenkinsopp, S.; Segy, G.

    1997-01-01

    Nine Alaskan representative crude oils and oil products with freshwater spill potential were collected, aged, and incubated in the presence of the standard freshwater inoculum for 28 days at 10 degrees C. Detailed analytical chemistry was performed on all samples to quantify compositional changes. All of the samples tested exhibited measurable hydrocarbon loss as a result of incubation with the freshwater inoculum. Total saturate and total n-alkane biodegradation were greatly enhanced when nutrients were present. The oil products Jet B Fuel and Diesel No. 2 appear to be more biodegradable than the Alaska North Slope and Cook Inlet crude oils tested, while the Bunker C/Diesel mixture appears to be less biodegradable than these crude oils. These results suggest that the screening procedures described here can provide useful information when applying bioremediation technology to the cleanup of selected oiled freshwater environments. 10 refs., 5 tabs., 13 figs

  20. 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.

  1. Modeling cutinase enzyme regulation in polyethylene terepthalate plastic biodegradation

    International Nuclear Information System (INIS)

    Apri, M.; Silmi, M.; Heryanto, T. E.; Moeis, M. R.

    2016-01-01

    PET (Polyethylene terephthalate) is a plastic material that is commonly used in our daily life. The high production of PET and others plastics that can be up to three hundred million tons per year, is not matched by its degradation rate and hence leads to environmental pollution. To overcome this problem, we develop a biodegradation system. This system utilizes LC Cutinase enzyme produced by engineered escherichia coli bacteria to degrade PET. To make the system works efficaciously, it is important to understand the mechanism underlying its enzyme regulation. Therefore, we construct a mathematical model to describe the regulation of LC Cutinase production. The stability of the model is analyzed. We show that the designated biodegradation system can give an oscillatory behavior that is very important to control the amount of inclusion body (the miss-folded proteins that reduce the efficiency of the biodegradation system).

  2. Modeling cutinase enzyme regulation in polyethylene terepthalate plastic biodegradation

    Science.gov (United States)

    Apri, M.; Silmi, M.; Heryanto, T. E.; Moeis, M. R.

    2016-04-01

    PET (Polyethylene terephthalate) is a plastic material that is commonly used in our daily life. The high production of PET and others plastics that can be up to three hundred million tons per year, is not matched by its degradation rate and hence leads to environmental pollution. To overcome this problem, we develop a biodegradation system. This system utilizes LC Cutinase enzyme produced by engineered escherichia coli bacteria to degrade PET. To make the system works efficaciously, it is important to understand the mechanism underlying its enzyme regulation. Therefore, we construct a mathematical model to describe the regulation of LC Cutinase production. The stability of the model is analyzed. We show that the designated biodegradation system can give an oscillatory behavior that is very important to control the amount of inclusion body (the miss-folded proteins that reduce the efficiency of the biodegradation system).

  3. Modeling cutinase enzyme regulation in polyethylene terepthalate plastic biodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Apri, M., E-mail: m.apri@math.itb.ac.id; Silmi, M. [Department of Mathematics, Institut Teknologi Bandung, Jalan Ganeca 10 Bandung, 40132 (Indonesia); Heryanto, T. E.; Moeis, M. R. [School of Life Sciences and Technology, Institut Teknologi Bandung, Jalan Ganeca 10 Bandung, 40132 (Indonesia)

    2016-04-06

    PET (Polyethylene terephthalate) is a plastic material that is commonly used in our daily life. The high production of PET and others plastics that can be up to three hundred million tons per year, is not matched by its degradation rate and hence leads to environmental pollution. To overcome this problem, we develop a biodegradation system. This system utilizes LC Cutinase enzyme produced by engineered escherichia coli bacteria to degrade PET. To make the system works efficaciously, it is important to understand the mechanism underlying its enzyme regulation. Therefore, we construct a mathematical model to describe the regulation of LC Cutinase production. The stability of the model is analyzed. We show that the designated biodegradation system can give an oscillatory behavior that is very important to control the amount of inclusion body (the miss-folded proteins that reduce the efficiency of the biodegradation system).

  4. Selected properties of biodegradable material produced from thermoplastic starch with by-products of food industry addition

    Directory of Open Access Journals (Sweden)

    Zdybel Ewa

    2017-06-01

    Full Text Available In this work extrusion process were used to create thermoplastic starch and to mix obtained starch with linen, quince and apple pomace at the same time. Obtained starch beads were formed in shapes. In experimental material was determined thermal conductivity, water absorption and the solubility in water. It is possible to get the biodegradable material produced from thermoplastic starch with an addition of fruit pomace. Adding pomace and glycerine to the biodegradable material made from starch change of susceptibility on water action. In the case of materials containing pomace, glycerine addition decreases the susceptibility on water action compared to the material manufactured with pomace addition but without glycerine. In the material containing pomace, glycerine addition caused the increase of the thermal insulation time compared to the material with pomace but no glycerine in it.

  5. Acetylated rice starches films with different levels of amylose: Mechanical, water vapor barrier, thermal, and biodegradability properties.

    Science.gov (United States)

    Colussi, Rosana; Pinto, Vânia Zanella; El Halal, Shanise Lisie Mello; Biduski, Bárbara; Prietto, Luciana; Castilhos, Danilo Dufech; Zavareze, Elessandra da Rosa; Dias, Alvaro Renato Guerra

    2017-04-15

    Biodegradable films from native or acetylated starches with different amylose levels were prepared. The films were characterized according to the mechanical, water vapor barrier, thermal, and biodegradability properties. The films from acetylated high amylose starches had higher moisture content and water solubility than the native high amylose starch film. However, the acetylation did not affect acid solubility of the films, regardless of the amylose content. Films made from high and medium amylose rice starches were obtained; however low amylose rice starches, whether native or acetylated, did not form films with desirable characteristics. The acetylation decreased the tensile strength and increased the elongation of the films. The acetylated starch-based films had a lower decomposition temperature and higher thermal stability than native starch films. Acetylated starches films exhibited more rapid degradation as compared with the native starches films. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. 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....

  7. Durability of Starch Based Biodegradable Plastics Reinforced with Manila Hemp Fibers

    OpenAIRE

    Shinji Ochi

    2011-01-01

    The biodegradability of Manila hemp fiber reinforced biodegradable plastics was studied for 240 days in a natural soil and 30 days in a compost soil. After biodegradability tests, weights were measured and both tensile strength tests and microscopic observation were performed to evaluate the biodegradation behavior of the composites. The results indicate that the tensile strength of the composites displays a sharp decrease for up to five days, followed by a gradual decrease. The weight loss a...

  8. 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.

  9. 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

  10. Biodegradation of concrete intended for their decontamination; 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 microorganisms 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)

  11. Biodegradability engineering of biodegradable Mg alloys: Tailoring the electrochemical properties and microstructure of constituent phases

    Science.gov (United States)

    Cha, Pil-Ryung; Han, Hyung-Seop; Yang, Gui-Fu; Kim, Yu-Chan; Hong, Ki-Ha; Lee, Seung-Cheol; Jung, Jae-Young; Ahn, Jae-Pyeong; Kim, Young-Yul; Cho, Sung-Youn; Byun, Ji Young; Lee, Kang-Sik; Yang, Seok-Jo; Seok, Hyun-Kwang

    2013-01-01

    Crystalline Mg-based alloys with a distinct reduction in hydrogen evolution were prepared through both electrochemical and microstructural engineering of the constituent phases. The addition of Zn to Mg-Ca alloy modified the corrosion potentials of two constituent phases (Mg + Mg2Ca), which prevented the formation of a galvanic circuit and achieved a comparable corrosion rate to high purity Mg. Furthermore, effective grain refinement induced by the extrusion allowed the achievement of much lower corrosion rate than high purity Mg. Animal studies confirmed the large reduction in hydrogen evolution and revealed good tissue compatibility with increased bone deposition around the newly developed Mg alloy implants. Thus, high strength Mg-Ca-Zn alloys with medically acceptable corrosion rate were developed and showed great potential for use in a new generation of biodegradable implants. PMID:23917705

  12. 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...

  13. Parallel pathways of ethoxylated alcohol biodegradation under aerobic conditions

    International Nuclear Information System (INIS)

    Zembrzuska, Joanna; Budnik, Irena; Lukaszewski, Zenon

    2016-01-01

    Non-ionic surfactants (NS) are a major component of the surfactant flux discharged into surface water, and alcohol ethoxylates (AE) are the major component of this flux. Therefore, biodegradation pathways of AE deserve more thorough investigation. The aim of this work was to investigate the stages of biodegradation of homogeneous oxyethylated dodecanol C_1_2E_9 having 9 oxyethylene subunits, under aerobic conditions. Enterobacter strain Z3 bacteria were chosen as biodegrading organisms under conditions with C_1_2E_9 as the sole source of organic carbon. Bacterial consortia of river water were used in a parallel test as an inoculum for comparison. The LC-MS technique was used to identify the products of biodegradation. Liquid-liquid extraction with ethyl acetate was selected for the isolation of C_1_2E_9 and metabolites from the biodegradation broth. The LC-MS/MS technique operating in the multiple reaction monitoring (MRM) mode was used for quantitative determination of C_1_2E_9, C_1_2E_8, C_1_2E_7 and C_1_2E_6. Apart from the substrate, the homologues C_1_2E_8, C_1_2E_7 and C_1_2E_6, being metabolites of C_1_2E_9 biodegradation by shortening of the oxyethylene chain, as well as intermediate metabolites having a carboxyl end group in the oxyethylene chain (C_1_2E_8COOH, C_1_2E_7COOH, C_1_2E_6COOH and C_1_2E_5COOH), were identified. Poly(ethylene glycols) (E) having 9, 8 and 7 oxyethylene subunits were also identified, indicating parallel central fission of C_1_2E_9 and its metabolites. Similar results were obtained with river water as inoculum. It is concluded that AE, under aerobic conditions, are biodegraded via two parallel pathways: by central fission with the formation of PEG, and by Ω-oxidation of the oxyethylene chain with the formation of carboxylated AE and subsequent shortening of the oxyethylene chain by a single unit. - Highlights: • Two parallel biodegradation pathways of alcohol ethoxylates have been discovered. • Apart from central fission

  14. The Compositions: Biodegradable Material - Typical Resin, as Moulding Sands’ Binders

    Directory of Open Access Journals (Sweden)

    Major-Gabryś K.

    2015-03-01

    Full Text Available The paper presents possibility of using biodegradable materials as parts of moulding sands’ binders based on commonly used in foundry practice resins. The authors focus on thermal destruction of binding materials and thermal deformation of moulding sands with tested materials. All the research is conducted for the biodegradable material and two typical resins separately. The point of the article is to show if tested materials are compatible from thermal destruction and thermal deformation points of view. It was proved that tested materials characterized with similar thermal destruction but thermal deformation of moulding sands with those binders was different.

  15. Biodegradable composites based on L-polylactide and jute fibres

    DEFF Research Database (Denmark)

    Plackett, David; Løgstrup Andersen, T.; Batsberg Pedersen, W.

    2003-01-01

    Biodegradable polymers can potentially be combined with plant fibres to produce biodegradable composite materials. In our research, a commercial L-polylactide was converted to film and then used in combination with jute fibre mats to generate composites by a film stacking technique. Composite...... in the 180-220 degreesC range were significantly higher than those of polylactide alone. Composite samples failed in a brittle fashion under tensile load and showed little sign of fibre pull-out. Examination of composite fracture surfaces using electron microscopy showed voids occurring between the jute...

  16. 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

  17. Estudio de fabricación de un masterbatch biodegradable

    OpenAIRE

    Sordo Rebollo, Laura

    2014-01-01

    En el present Treball Final de Grau es desenvolupa el procés de fabricació d´un masterbatch biodegradable, un concentrat de color per aplicar a polímers biodegradables, concretamente, es tracta d´un masterbatch de color verd fabricat amb base polímèrica de PLA 2003D. Producte relativamente nou, innovador, diferent i amb moltes possiblitats en un futur pròxim, la finalitat principal del qual es fer-se un espai en el mercat dels plàstics convencionals i substituir-los poc a po...

  18. Effect of Material Parameters on Mechanical Properties of Biodegradable Polymers/Nanofibrillated Cellulose (NFC) Nano Composites

    Science.gov (United States)

    Yottha Srithep; Ronald Sabo; Craig Clemons; Lih-Sheng Turng; Srikanth Pilla; Jun Peng

    2012-01-01

    Using natural cellulosic fibers as fillers for biodegradable polymers can result in fully biodegradable composites. Biodegradable composites were prepared using nanofibrillated cellulose (NFC) as the reinforcement and poly (3-hydroxybutyrate-co-3-hydroxyvalerate, PHBV) as the polymer matrix. The objective of this study was to determine how various additives (i.e.,...

  19. Effects of chronic pollution and water flow intermittency on stream biofilms biodegradation capacity.

    Science.gov (United States)

    Rožman, Marko; Acuña, Vicenç; Petrović, Mira

    2018-02-01

    A mesocosm case study was conducted to gain understanding and practical knowledge on biofilm emerging contaminants biodegradation capacity under stressor and multiple stressor conditions. Two real life scenarios: I) biodegradation in a pristine intermittent stream experiencing acute pollution and II) biodegradation in a chronically polluted intermittent stream, were examined via a multifactorial experiment using an artificial stream facility. Stream biofilms were exposed to different water flow conditions i.e. permanent and intermittent water flow. Venlafaxine, a readily biodegradable pharmaceutical was used as a measure of biodegradation capacity while pollution was simulated by a mixture of four emerging contaminants (erythromycin, sulfisoxazole, diclofenac and imidacloprid in addition to venlafaxine) in environmentally relevant concentrations. Biodegradation kinetics monitored via LC-MS/MS was established, statistically evaluated, and used to link biodegradation with stress events. The results suggest that the effects of intermittent flow do not hinder and may even stimulate pristine biofilm biodegradation capacity. Chronic pollution completely reduced biodegradation in permanent water flow experimental treatments while no change in intermittent streams was observed. A combined effect of water flow conditions and emerging contaminants exposure on biodegradation was found. The decrease in biodegradation due to exposure to emerging contaminants is significantly greater in streams with permanent water flow suggesting that the short and medium term biodegradation capacity in intermittent systems may be preserved or even greater than in perennial streams. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. 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

  1. Biocompatibility, osteointegration, osteoconduction, and biodegradation of a hydroxyapatite-polyhydroxybutyrate composite

    Directory of Open Access Journals (Sweden)

    Emily Correna Carlo Reis

    2010-08-01

    Full Text Available In this work, biocompatibility, osteointegration, osteoconductivity, and biodegradation of a hydroxyapatite polyhydroxybutyrate new composite were evaluated. The composite was implanted in rabbits' bone defects and clinical, radiographic, histological, and histomorphometric data of these animals were compared with those of unfilled defects on the days 8th, 45th, and 90th after surgery. No significant differences existed between the groups for the evaluated clinical parameters. Radiographs showed bone-composite direct contact. Bone formed within the defect, interface and inside the composite. Significant differences were found between the bone and connective tissues percentage within the defect at all dates and at the interface on the 45th day, bone tissue prevailing. Composite's biodegradation signs were evident: giant cells on the surface of composite fragments separated from the original block in the absence of inflammatory infiltrate. These data supported that such composite was biocompatible, biodegradable, osteoconductive and integrate to bone.A biocompatibilidade, osteointegração, osteocondução e biodegradação de um novo compósito de hidroxiapatita e polihidroxibutirato foram avaliados. O compósito foi implantado em defeitos ósseos em coelhos e dados clínicos, radiográficos, histológicos e histomorfométricos foram comparados aos de defeitos não preenchidos aos 8, 45 e 90 dias após a cirurgia. Não foram observadas diferenças significantes entre os grupos para os parâmetros clínicos avaliados. Contato direto entre osso e compósito foi observado nas radiografias. Tecido ósseo se formou dentro do defeito, interface e dentro do compósito. Foram observadas diferenças significativas entre a porcentagem dos tecidos ósseo e conjuntivo dentro do defeito em todas as datas de avaliação e na interface aos 45 dias, com predominância do tecido ósseo. Sinais de biodegradação foram observados: células gigantes na superf

  2. Unprecedented access to functional biodegradable polymers and coatings

    NARCIS (Netherlands)

    Lee, Jung Seok; Wang, Rong; Chen, Wei; Meng, Fenghua; Cheng, Ru; Deng, Chao; Feijen, Jan; Zhong, Zhiyuan

    2011-01-01

    The ever-growing biomedical technology such as tissue engineering, regenerative medicine, and controlled drug release intimately relies on the development of advanced functional biomaterials. Here, we report on versatile and robust synthesis of novel vinyl sulfone (VS)-functionalized biodegradable

  3. Feasibility of biodegradation of pentachlorophenol in scrap wood

    International Nuclear Information System (INIS)

    Beaulieu, G.; Besner, A.; Gilbert, R.; Tetreault, P.; Beaudet, R.; Bisaillon, J. G.; Lepine, F.; Ottou, J. M.; Sansregret, J. L.; Lei, J.

    1998-04-01

    The feasibility of biological treatment of scrap wood impregnated in pentachlorophenol (PCP) was investigated using wood samples impregnated with PCP for biodegradation experiments by the Hydro-Quebec Research Institute (IREQ). IREQ identified the necessity of pre-treating the wood, first by shredding wood poles into wood shavings, followed by mechanical milling of the shavings to obtain wood dust. Biodegradation experiments under anaerobic conditions were performed by the Armand-Frappier Institute by isolating a consortium of bacteria from a mixture of PCP-contaminated soils and a municipal anaerobic sludge that was able to degrade PCP under anaerobic methanogenic conditions at 29 degrees C. A complementary source of carbon was found to be necessary for the bacterial consortium to degrade the PCP. The best PCP degradation results were obtained with an aerobic fixed-film reactor. Aerobic biodegradation tests were performed on liquor extracted from wood dust contaminated with PCP. The anaerobic fixed field reactor was able to completely degrade the PCP extracted from wood dust in less than one day. Aerobic biodegradation was also investigated using microorganisms and fungi. Over a four month experimental period only low concentrations of PCP were found in effluents treated with the aerobic cultures. 117 refs., 38 tabs., 31 figs

  4. Biodegradation and moisture uptake modified starch-filled Linear ...

    African Journals Online (AJOL)

    Sixteen different modified-cassava starch-LLDPE blends containing starch in the range of 10-40% by weight were prepared. Calcium chloride, D-glucose, chloroform and alumina were differently used as modifying agents. The Moisture uptake and biodegradation of each of the composites were investigated. Both of these ...

  5. Ecotoxicity and biodegradability of new brominated flame retardants: A review

    Czech Academy of Sciences Publication Activity Database

    Ezechiáš, Martin; Covino, Stefano; Cajthaml, Tomáš

    2014-01-01

    Roč. 110, č. 2 (2014), s. 153-167 ISSN 0147-6513 R&D Projects: GA MŠk(CZ) EE2.3.30.0003; GA TA ČR TE01020218 Institutional support: RVO:61388971 Keywords : Ecotoxicity * brominated flame retardants * biodegradation * review Subject RIV: EE - Microbiology, Virology Impact factor: 2.762, year: 2014

  6. Biodegradation of Synthetic Polymers by Composting and Fungal Treatment

    Czech Academy of Sciences Publication Activity Database

    Šašek, Václav; Vitásek, J.; Chromcová, D.; Prokopová, I.; Brožek, J.; Náhlík, J.

    2006-01-01

    Roč. 51, č. 5 (2006), s. 425-430 ISSN 0015-5632 R&D Projects: GA ČR GA203/03/0508 Institutional research plan: CEZ:AV0Z50200510 Keywords : biodegradation * composting * synthetic polymers Subject RIV: EE - Microbiology, Virology Impact factor: 0.963, year: 2006

  7. Biodegradable microfabricated plug-filters for glaucoma drainage devices.

    Science.gov (United States)

    Maleki, Teimour; Chitnis, Girish; Park, Jun Hyeong; Cantor, Louis B; Ziaie, Babak

    2012-06-01

    We report on the development of a batch fabricated biodegradable truncated-cone-shaped plug filter to overcome the postoperative hypotony in nonvalved glaucoma drainage devices. Plug filters are composed of biodegradable polymers that disappear once wound healing and bleb formation has progressed past the stage where hypotony from overfiltration may cause complications in the human eye. The biodegradable nature of device eliminates the risks associated with permanent valves that may become blocked or influence the aqueous fluid flow rate in the long term. The plug-filter geometry simplifies its integration with commercial shunts. Aqueous humor outflow regulation is achieved by controlling the diameter of a laser-drilled through-hole. The batch compatible fabrication involves a modified SU-8 molding to achieve truncated-cone-shaped pillars, polydimethylsiloxane micromolding, and hot embossing of biodegradable polymers. The developed plug filter is 500 μm long with base and apex plane diameters of 500 and 300 μm, respectively, and incorporates a laser-drilled through-hole with 44-μm effective diameter in the center.

  8. 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.

  9. 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)

  10. Biodegradation of 2 - methoxyethanol by a new bacterium isolate ...

    African Journals Online (AJOL)

    Microbial biodegradation of 2-methoxyethanol also known as Methyl glycol (MG) under anaerobic conditions has received much attention during the past decade. However, not much is known about the aerobic degradation of 2-methoxyethanol. Samples from various environmental niches were enriched to isolate and ...

  11. Aerobic biodegradation of vinyl chloride in groundwater samples

    International Nuclear Information System (INIS)

    Davis, J.W.; Carpenter, C.L.

    1990-01-01

    Studies were conducted to examine the biodegradation of 14 C-labeled vinyl chloride in samples taken from a shallow aquifer. Under aerobic conditions, vinyl chloride was readily degraded, with greater than 99% of the labeled material being degraded after 108 days and approximately 65% being mineralized to 14 CO 2

  12. Nanofibers extraction from palm mesocarp fiber for biodegradable polymers incorporation

    International Nuclear Information System (INIS)

    Kuana, Vanessa A.; Rodrigues, Vanessa B.; Takahashi, Marcio C.; Campos, Adriana de; Sena Neto, Alfredo R.; Mattoso, Luiz H.C.; Marconcini, Jose M.

    2015-01-01

    The palm mesocarp fibers are residues produced by the palm oil industries. The objective of this paper is to determine an efficient treatment to extract crystal cellulose nanofibers from the palm mesocarp fibers to be incorporated in biodegradable polymeric composites. The fibers were saponified, bleached and analyzed with thermal gravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. (author)

  13. Aerobic biodegradation of a mixture of chlorinated organics in ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-04

    Jul 4, 2008 ... DCM; and 0.232 – 0.588 week-1 for DCA in both water microcosms with higher degradation generally observed in New ... Key words: Bioaugmentation, biodegradation, biostimulation, chlorinated aliphatic hydrocarbons, microcosms. ... culture (OD of 1 at λ600) of the consortia was added separately to.

  14. Enhanced aerobic biodegradation of some toxic hydrocarbon pollutants

    International Nuclear Information System (INIS)

    Elshahawy, M.R.M.

    2007-01-01

    samples were collected from the same location in Suez Gulf during the period from June, 2004 to April 2006 then microbiologically and chemically analyzed . the TPH levels ranged from 55 to 86 ppm and exceeded the known permissible limits referring to a settled situation of chronic hydrocarbon pollution in the studied area. 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 ranged between 26 and 50% over the period of collection. the biodegradation potentials of suez gulf consortia were studied at different concentrations of phenanthrene as a sole carbon source. it was found that the degradation kinetics of phenanthrene either due to biotic or abiotic factors is affected with the initial concentration of PAHs. twenty PAHs degraders were isolated from Suez Gulf consortia after different adaptation periods on phenanthrene.ten isolates were selected to be promising due to their ability to tolerate high base oil concentrations, grow at wide range of temperatures and their short incubation period on MSO. the biodegradation kinetics of 200 ppm phenanthrene by the selected isolates was monitored by HPLC

  15. A field evaluation of coated urea with biodegradable materials and ...

    African Journals Online (AJOL)

    ajl yemi

    2011-12-28

    Dec 28, 2011 ... Urease inhibitor and biodegradable polymer coatings are two most suitable startegies to increase urea fertilizer efficiency. Coating of urea with selected inhibitors can increase the crop production by slowing down the hydrolysis process of urea in the soil. For this purpose, a field experiment was conducted ...

  16. Application of a Biodegradable Lubricant in a Diesel Vehicle

    DEFF Research Database (Denmark)

    Schramm, Jesper

    2003-01-01

    , NOx, THC, PM, lubricant-SOF and PAH from one diesel and one gasoline type vehicle using biodegradable lubricants and conventional lubricants. This paper describes the results of the experiments with the diesel type vehicle only. Lubricant consumption and fuel consumption are other important parameters...

  17. Biodegradation of orange G by a novel isolated bacterial strain ...

    African Journals Online (AJOL)

    At these optimum levels of parameters, bacterial decolorization of orange G by 94.48% was obtained under static conditions. Biodegradation and decolorization of azo dye, orange G, was confirmed using UV-VIS spectrophotometry, thin layer chromatography (TLC) and fourier transform infrared spectroscopy (FTIR) and ...

  18. Characterisation and biodegradation of settleable organic matter for ...

    African Journals Online (AJOL)

    Biodegradation of settled COD is studied by evaluating the associated OUR profile obtained in an aerated batch reactor. Hydrolysis was selected, as in current modelling, as the rate-limiting step for O2 consumption. Settled COD was found to incorporate a significant fraction of active biomass that needs to be accounted for ...

  19. A review on biodegradable materials for cardiovascular stent application

    Science.gov (United States)

    Hou, Li-Da; Li, Zhen; Pan, Yu; Sabir, MuhammadIqbal; Zheng, Yu-Feng; Li, Li

    2016-09-01

    A stent is a medical device designed to serve as a temporary or permanent internal scaffold to maintain or increase the lumen of a body conduit. The researchers and engineers diverted to investigate biodegradable materials due to the limitation of metallic materials in stent application such as stent restenosis which requires prolonged anti platelet therapy, often result in smaller lumen after implantation and obstruct re-stenting treatments. Biomedical implants with temporary function for the vascular intervention are extensively studied in recent years. The rationale for biodegradable stent is to provide the support for the vessel in predicted period of time and then degrading into biocompatible constituent. The degradation of stent makes the re-stenting possible after several months and also ameliorates the vessel wall quality. The present article focuses on the biodegradable materials for the cardiovascular stent. The objective of this review is to describe the possible biodegradable materials for stent and their properties such as design criteria, degradation behavior, drawbacks and advantages with their recent clinical and preclinical trials.

  20. The development and performance testing of a biodegradable scale inhibitor

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, Julie; Fidoe, Steve; Jones, Chris

    2006-03-15

    The oil industry is currently facing severe restrictions concerning the discharge of oil field chemicals into the environment. Many commonly used materials in both topside and downhole applications are phased for substitution for use in the North Sea, and more will be identified. The development of biodegradable and low toxicity chemicals, which afford equal or improved efficacy, compared to conventional technology, available at a competitive price, is a current industry challenge. A range of biodegradable materials are increasingly available, however their limited performance can result in a restricted range of applications. This paper discusses the development and commercialization of a readily biodegradable scale inhibitor, ideal for use in topside applications. This material offers a broad spectrum of activity, notably efficiency against barium sulphate, calcium sulphate and calcium carbonate scales, in a range of water chemistries. A range of performance testing, compatibility, stability and OCNS dataset will be presented. Comparisons with commonly used chemicals have been made to identify the superior performance of this phosphate ester. This paper will discuss a scale inhibitor suitable for use in a variety of conditions which offers enhanced performance combined with a favourable biodegradation profile. This material is of great benefit to the industry, particularly in North Sea applications. (author) (tk)

  1. Bio-Based Polymers with Potential for Biodegradability

    Directory of Open Access Journals (Sweden)

    Thomas F. Garrison

    2016-07-01

    Full Text Available A variety of renewable starting materials, such as sugars and polysaccharides, vegetable oils, lignin, pine resin derivatives, and proteins, have so far been investigated for the preparation of bio-based polymers. Among the various sources of bio-based feedstock, vegetable oils are one of the most widely used starting materials in the polymer industry due to their easy availability, low toxicity, and relative low cost. Another bio-based plastic of great interest is poly(lactic acid (PLA, widely used in multiple commercial applications nowadays. There is an intrinsic expectation that bio-based polymers are also biodegradable, but in reality there is no guarantee that polymers prepared from biorenewable feedstock exhibit significant or relevant biodegradability. Biodegradability studies are therefore crucial in order to assess the long-term environmental impact of such materials. This review presents a brief overview of the different classes of bio-based polymers, with a strong focus on vegetable oil-derived resins and PLA. An entire section is dedicated to a discussion of the literature addressing the biodegradability of bio-based polymers.

  2. Biodegradable Metals for Cardiovascular Stent Application: Interests and New Opportunities

    Science.gov (United States)

    Moravej, Maryam; Mantovani, Diego

    2011-01-01

    During the last decade, biodegradable metallic stents have been developed and investigated as alternatives for the currently-used permanent cardiovascular stents. Degradable metallic materials could potentially replace corrosion-resistant metals currently used for stent application as it has been shown that the role of stenting is temporary and limited to a period of 6–12 months after implantation during which arterial remodeling and healing occur. Although corrosion is generally considered as a failure in metallurgy, the corrodibility of certain metals can be an advantage for their application as degradable implants. The candidate materials for such application should have mechanical properties ideally close to those of 316L stainless steel which is the gold standard material for stent application in order to provide mechanical support to diseased arteries. Non-toxicity of the metal itself and its degradation products is another requirement as the material is absorbed by blood and cells. Based on the mentioned requirements, iron-based and magnesium-based alloys have been the investigated candidates for biodegradable stents. This article reviews the recent developments in the design and evaluation of metallic materials for biodegradable stents. It also introduces the new metallurgical processes which could be applied for the production of metallic biodegradable stents and their effect on the properties of the produced metals. PMID:21845076

  3. 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.

  4. Biodegradable xylitol-based elastomers: In vivo behavior and biocompatibility

    NARCIS (Netherlands)

    J.P. Bruggeman (Joost); C.J. Bettinger (Christopher); R.S. Langer (Robert)

    2010-01-01

    textabstractBiodegradable elastomers based on polycondensation reactions of xylitol with sebacic acid, referred to as poly(xylitol sebacate) (PXS) elastomers have recently been developed. We describe the in vivo behavior of PXS elastomers. Four PXS elastomers were synthesized, characterized, and

  5. Biodegrading effects of some rot fungi on Pinus caribaea wood

    African Journals Online (AJOL)

    STORAGESEVER

    2008-05-16

    May 16, 2008 ... species of white-rot fungi; Corioliopsis polyzona and Pleurotus squarrosulus, and two species of brown- rot fungi; Lentinus ... The results indicated that biodegradation by rot fungi differs in intensity according to the fungus ..... wood of coast red wood Sequoia Sempervirens (D. Don). For. Prod. J. 33(5): 15-20 ...

  6. Influence of chemical structures on biodegradation of azo dyes by ...

    African Journals Online (AJOL)

    Influence of chemical structures on biodegradation of azo dyes by Pseudomonas sp. NA Oranusi, CJ Ogugbue. Abstract. No Abstract. Global Journal of Environmental Sciences Vol. 5(1) 2006: 19-25. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  7. Biodegradable bags for the production of plant seedlings

    Directory of Open Access Journals (Sweden)

    Ana Paula Bilck

    2014-10-01

    Full Text Available The production of plant seedlings has traditionally used polyethylene bags, which are thrown out in the soil or burned after transplant because the large amount of organic material attached to the bags makes recycling difficult. Additionally, when a seedling is taken from the bag for transplant, there is the risk of root damage, which compromises the plant’s development. In this study, we developed biodegradable bags to be used in seedling production, and we verify their influence on the development of Brazilian ginseng (Pfaffia glomerata (Spreng Pedersen, when the plant is planted without being removed from the bag. Both black and white biodegradable bags remained intact throughout the seedling production period (60 days. After being transplanted into containers (240 days, they were completely biodegraded, and there was no significant difference between the dry mass of these plants and that of plants that were transplanted without the bags. The plants that were cultivated without being removed from the polyethylene bags had root development difficulties, and the wrapping showed no signs of degradation. The use of biodegradable films is an alternative for the production of bags for seedlings, as these can then be transplanted directly into the soil without removing the bag, reducing the risk of damage to the roots during the moment of transplant.

  8. 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

  9. Improving oil biodegradability of aliphatic crude oil fraction by ...

    African Journals Online (AJOL)

    The percentage of biodegrading ability of B. subtilis and the mixture of these bacteria to n-alkanes and isoprenoids (pristine, phytane) were measured and compared with control. Crude oil is used as a sole source of energy and the incubation period was 24 days, the hydrocarbons loss are detected each 6 day interval using ...

  10. Microbial community dynamics in diesel waste biodegradation using ...

    African Journals Online (AJOL)

    Microbial community dynamics in diesel waste biodegradation using sequencing batch bioreactor operation mode (SBR) ... African Journal of Biotechnology ... Oxygen uptake rate (OUR) indicated increases in microbial activity from cycle one to cycle two (124.9 to 252.9 mgO2/L/h) and decreases in cycles three and four ...

  11. 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.

  12. Characterization of biodegradable polycaprolactone containing titanium dioxide micro and nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Govorčin Bajsić, E.; Ocelić Bulatović, V.; Šlouf, Miroslav; Šitum, Ana

    2014-01-01

    Roč. 8, č. 7 (2014), s. 536-540 ISSN 2010-376X R&D Projects: GA TA ČR TE01020118 Institutional support: RVO:61389013 Keywords : morphology * polycaprolactone * thermal properties Subject RIV: EA - Cell Biology http://waset.org/Publication/characterization-of-biodegradable-polycaprolactone-containing-titanium-dioxide-micro-and-nanoparticles/9998694

  13. Nonionic surfactant Brij35 effects on toluene biodegradation in a ...

    African Journals Online (AJOL)

    Nonionic surfactant effects on the toluene dissolved in the water phase and biodegradation kinetic behaviors of toluene in a composite bead biofilter were investigated. The toluene dissolved in the water phase was enhanced by the addition of surfactant into aqueous solution and the enhancing effect was more pronounced ...

  14. Acute aquatic toxicity and biodegradation potential of biodiesel fuels

    International Nuclear Information System (INIS)

    Haws, R.A.; Zhang, X.; Marshall, E.A.; Reese, D.L.; Peterson, C.L.; Moeller, G.

    1995-01-01

    Recent studies on the biodegradation potential and aquatic toxicity of biodiesel fuels are reviewed. Biodegradation data were obtained using the shaker flask method observing the appearance of CO 2 and by observing the disappearance of test substance with gas chromatography. Additional BOD 5 and COD data were obtained. The results indicate the ready biodegradability of biodiesel fuels as well as the enhanced co-metabolic biodegradation of biodiesel and petroleum diesel fuel mixtures. The study examined reference diesel, neat soy oil, neat rape oil, and the methyl and ethyl esters of these vegetable oils as well as various fuel blends. Acute toxicity tests on biodiesel fuels and blends were performed using Oncorhynchus mykiss (Rainbow Trout) in a static non-renewal system and in a proportional dilution flow replacement system. The study is intended to develop data on the acute aquatic toxicity of biodiesel fuels and blends under US EPA Good Laboratory Practice Standards. The test procedure is designed from the guidelines outlined in Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms and the Fish Acute Aquatic Toxicity Test guideline used to develop aquatic toxicity data for substances subject to environmental effects test regulations under TSCA. The acute aquatic toxicity is estimated by an LC50, a lethal concentration effecting mortality in 50% of the test population

  15. Biodegradable Metals for Cardiovascular Stent Application: Interests and New Opportunities

    Directory of Open Access Journals (Sweden)

    Maryam Moravej

    2011-06-01

    Full Text Available During the last decade, biodegradable metallic stents have been developed and investigated as alternatives for the currently-used permanent cardiovascular stents. Degradable metallic materials could potentially replace corrosion-resistant metals currently used for stent application as it has been shown that the role of stenting is temporary and limited to a period of 6–12 months after implantation during which arterial remodeling and healing occur. Although corrosion is generally considered as a failure in metallurgy, the corrodibility of certain metals can be an advantage for their application as degradable implants. The candidate materials for such application should have mechanical properties ideally close to those of 316L stainless steel which is the gold standard material for stent application in order to provide mechanical support to diseased arteries. Non-toxicity of the metal itself and its degradation products is another requirement as the material is absorbed by blood and cells. Based on the mentioned requirements, iron-based and magnesium-based alloys have been the investigated candidates for biodegradable stents. This article reviews the recent developments in the design and evaluation of metallic materials for biodegradable stents. It also introduces the new metallurgical processes which could be applied for the production of metallic biodegradable stents and their effect on the properties of the produced metals.

  16. 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.

  17. Biodegradation of low density polyethylene (LDPE) by a new ...

    African Journals Online (AJOL)

    aghomotsegin

    The microbial degradation of LDPE was also analyzed by the change in pH of the culture ... The generation of biodegradable polyethylene requires ...... Use of scanning electron microscope for the examination of actinomycetes. J. Gen. Microbiol. 48:171-177. Yamada-Onodera K, Mukumoto H, Katsuyaya Y, Saiganji A, Tani ...

  18. Rate of biodegradation of crude oil by microorganisms isolated from ...

    African Journals Online (AJOL)

    The rate of biodegradation of crude oil by micro-organisms isolated from crude oil sludge environment in Eket, Akwa Ibom State of Nigeria was studied. Mineral salt medium supplemented with crude oil was used and three most abundant species isolated from a crude oil sludged soil - Micrococcus varians, Bacillus subtilis ...

  19. The use of ecocores to evaluate biodegradation in marine sediments

    DEFF Research Database (Denmark)

    Jensen, Kurt; Albrechtsen, Hans-Jørgen; Nielsen, Jef

    1988-01-01

    A laboratory sediment microcosm called the ecocore is described. It has been used to test the biodegradability of substances which predominantly enter the sediment. A new method for introducing hydrophobic test substances such as hydrocarbons to the test system is also described. In a series...

  20. Evaluation of nutrient addition to diesel biodegradation | Singh ...

    African Journals Online (AJOL)

    Increasing public concern towards petroleum pollution demands for new and more environmentally efficient low-cost strategies for cleaning up contaminated sites. Diesel biodegradation by microbial communities was investigated in artificially contaminated soils by supplementing commercial fertilizers under laboratory ...

  1. A field evaluation of coated urea with biodegradable materials and ...

    African Journals Online (AJOL)

    Urease inhibitor and biodegradable polymer coatings are two most suitable startegies to increase urea fertilizer efficiency. Coating of urea with selected inhibitors can increase the crop production by slowing down the hydrolysis process of urea in the soil. For this purpose, a field experiment was conducted to evaluate the ...

  2. MICROORGANISMS’ SURFACE ACTIVE SUBSTANCES ROLE IN HYDROCARBONS BIODEGRADATION

    Directory of Open Access Journals (Sweden)

    Оlga Vasylchenko

    2012-09-01

    Full Text Available  Existing data and publications regarding oil, hydrocarbon biodegradation, metabolism, and bioremediation were analyzed. Search of hydrocarbon degrading bacteria which are producers of biosurfactants was provided, types of microbial surfactants and their physiological role were analyzed and ordered. The study of factors affecting the surface active properties of producers’ cultures was done.

  3. 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).

  4. Stimuli-responsive biodegradable polymeric micelles for targeted cancer therapy

    NARCIS (Netherlands)

    Talelli, M.A.

    2011-01-01

    Thermosensitive and biodegradable polymeric micelles based on mPEG-b-pHPMAmLacn have shown very promising results during the past years. The results presented in this thesis illustrate the high potential of these micelles for anticancer therapy and imaging and fully justify further pharmaceutical

  5. Biodegradability and Microbial Toxicity of Aircraft Fuel System Icing Inhibitors

    National Research Council Canada - National Science Library

    Meshako, Charles

    1996-01-01

    ...%. These concentrations raise concerns as to the disposal and handling of these wastes. The current FSII, DiEGME was evaluated along with two new candidates, dipropylene glycol and glycerol formal DiEGME appeared to be moderately but not completely biodegradable...

  6. Stereoselective biodegradation of tricyclic terpanes in heavy oils from the Bolivar Coastal Fields, Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, M. [Stanford University (United States). Dept. of Geological and Environmental Sciences; PDVSA-Intevep, Caracas (Venezuela); Moldowan, J.M.; Dahl, J.E. [Stanford University (United States). Dept. of Geological and Environmental Sciences; Peters, K.E. [Mobil Technology Co., Dallas, TX (United States)

    2001-07-01

    Gas chromatography-mass spectrometry (GC-MS) and GC-MS-MS analyses of heavy oils from Bolivar Coastal Fields (Lagunillas Field) show a complete set of demethylated tricyclic terpanes. As is the case for the 25-norhopanes, the demethylated tricyclics are probably formed in reservoirs by microbially-mediated removal of the methyl group from the C-10 position, generating putative 17-nor-tricyclic terpanes. Diastereomeric pairs of tricyclic terpanes are resolved above C{sub 24} due to resolution of 22S and 22R epimers, but the elution order of the 22S and 22R epimers is unknown. Early-eluting diastereomers (EE) predominate over late-eluting diastereomers (LE) (C{sub 25}-C{sub 29}) in the heavily degraded oils, indicating a stereoselective preference for the LE stereoisomers during biodegradation. Conversely, the LE diastereomers predominate over the EE diastereomers in the 17-nor tricyclic series (C{sub 24}-C{sub 28}), indicating that tricyclic terpanes and 17-nor-tricyclic terpanes are directly linked as precursors and products, respectively. A good correlation exists between the destruction of steranes and the demethylation of hopanes and tricyclic terpanes. This suggests that terpane demethylation occurs during sterane destruction and hopane demethylation, although the rate is slower, indicating that tricyclic terpanes are more resistant to biodegradation. (Author)

  7. Synthesis and characterization of highly-magnetic biodegradable poly(D,L-lactide-co-glycolide) nanospheres.

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.; Kaminski, M. D.; Chen, H.; Torno, M.; Taylor, L.; Rosengart, A. J.; Univ. of Chicago

    2007-05-14

    The objective of this study was to develop high magnetization, biodegradable/biocompatible polymer-coated magnetic nanospheres for biomedical applications. Magnetic spheres were prepared by a modified single oil-in-water emulsion-solvent evaporation method utilizing highly-concentrated hydrophobic magnetite and poly(d,l lactide-co-glycolide) (PLGA). Hydrophobic magnetite prepared using oleic acid exhibited high magnetite concentrations (84 wt.%) and good miscibility with biopolymer solvents to form a stable oily suspension. The oily suspension was then emulsified within an aqueous solution containing poly(vinyl alcohol). After rapid evaporation of the organic solvent, we obtained solid magnetic nanospheres. We characterized these spheres in terms of external morphology, microstructure, size and zeta potential, magnetite content and distribution within the nanospheres, and magnetic properties. The results showed good encapsulation where the magnetite distorted the smooth surface morphology only at the highest magnetite concentrations. The mean diameter was 360-370 nm with polydispersity indices of 0.12-0.20. We obtained high magnetite content (40-60%) and high magnetization (26-40 emu/g). The high magnetization properties were obtained while leaving sufficient polymer to retain drugs making these biodegradable spheres suitable as a potential platform for the design of magnetically-guided drug delivery and other in vivo biomagnetic applications.

  8. Heavy metal-immobilizing organoclay facilitates polycyclic aromatic hydrocarbon biodegradation in mixed-contaminated soil

    International Nuclear Information System (INIS)

    Biswas, Bhabananda; Sarkar, Binoy; Mandal, Asit; Naidu, Ravi

    2015-01-01

    Highlights: • A novel metal-immobilizing organoclay (MIOC) synthesized and characterized. • MIOC immobilizes toxic metals and reduces metal bioavailability. • It enhances PAH-bioavailability to soil bacteria. • It improves microbial growth and activities in mixed-contaminated soils. • MIOC facilitates PAH-biodegradation in metal co-contaminated soils. - Abstract: Soils contaminated with a mixture of heavy metals and polycyclic aromatic hydrocarbons (PAHs) pose toxic metal stress to native PAH-degrading microorganisms. Adsorbents such as clay and modified clay minerals can bind the metal and reduce its toxicity to microorganisms. However, in a mixed-contaminated soil, an adsorption process more specific to the metals without affecting the bioavailability of PAHs is desired for effective degradation. Furthermore, the adsorbent should enhance the viability of PAH-degrading microorganisms. A metal-immobilizing organoclay (Arquad ® 2HT-75-bentonite treated with palmitic acid) (MIOC) able to reduce metal (cadmium (Cd)) toxicity and enhance PAH (phenanthrene) biodegradation was developed and characterized in this study. The MIOC differed considerably from the parent clay in terms of its ability to reduce metal toxicity (MIOC > unmodified bentonite > Arquad–bentonite). The MIOC variably increased the microbial count (10–43%) as well as activities (respiration 3–44%; enzymatic activities up to 68%), and simultaneously maintained phenanthrene in bioavailable form in a Cd-phenanthrene mixed-contaminated soil over a 21-day incubation period. This study may lead to a new MIOC-assisted bioremediation technique for PAHs in mixed-contaminated soils

  9. Tailoring the mechanical and biodegradable properties of binary blends of biomedical thermoplastic elastomer.

    Science.gov (United States)

    Ang, Hui Ying; Chan, Jingni; Toong, Daniel; Venkatraman, Subbu S; Chia, Sing Joo; Huang, Ying Ying

    2018-03-01

    Blending polymers with complementary properties capitalizes on the inherent advantages of both components, making it possible to tailor the behaviour of the resultant material. A polymer blend consisting of an elastomer and thermoplastic can help to improve the mechanical integrity of the system without compromising on its processibility. A series of blends of biodegradable Poly(L-lactide-co-ɛ-caprolactone) (PLC) and Poly-(l,l-lactide-co-glycolic acid) (PLLGA), and PLC with Poly-(d,l-lactide-co-glycolic acid) (PDLLGA) were evaluated as a potential material for a biodegradable vesicourethral connector device. Based on the Tg of the blends, PLC/PLLGA formed an immiscible mixture while PLC/PDLLGA resulted in a compatible blend. The results showed that with the blending of PLC, the failure mode of PLLGA and PDLLGA changed from brittle to ductile fracture, with an significant decreas in tensile modulus and strength. SEM images demonstrated the different blend morphologies of different compositions during degradation. Gel Permeation Chromatography (GPC) and mechanical characterization revealed the degradation behaviour of the blends in this order (fastest to slowest): PDLLGA and PLC/PDLLGA blends > PLLGA and PLC/PLLGA blends > PLC. The PLC/PLLGA (70:30) blend was recommended as a suitable for the vesicourethral connector device application, highlighting the tailoring of blends to achieve a desired mechanical performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Investigation of Carboxymethyl Cellulose (CMC on Mechanical Properties of Cold Water Fish Gelatin Biodegradable Edible Films

    Directory of Open Access Journals (Sweden)

    Mahsa Tabari

    2017-05-01

    Full Text Available The tendency to use biocompatible packages, such as biodegradable films, is growing since they contain natural materials, are recyclable and do not cause environmental pollution. In this research, cold water fish gelatin and carboxymethyl cellulose were combined for use in edible films. Due to its unique properties, gelatin is widely used in creating gel, and in restructuring, stabilizing, emulsifying, and forming foam and film in food industries. This research for the first time modified and improved the mechanical properties of cold water fish gelatin films in combination with carboxymethyl cellulose. Cold water fish gelatin films along with carboxymethyl cellulose with concentrations of 0%, 5%, 10%, 20% and 50% were prepared using the casting method. The mechanical properties were tested by the American National Standard Method. Studying the absorption isotherm of the resulting composite films specified that the humidity of single-layer water decreased (p < 0.05 and caused a reduction in the equilibrium moisture of these films. In the mechanical testing of the composite films, the tensile strength and Young’s modulus significantly increased and the elongation percent significantly decreased with the increase in the concentration of carboxymethyl cellulose. Considering the biodegradability of the films and the improvement of their mechanical properties by carboxymethyl cellulose, this kind of packaging can be used in different industries, especially the food industry, as an edible coating for packaging food and agricultural crops.

  11. Tailored biodegradable triblock copolymer coatings obtained by MAPLE: a parametric study

    Science.gov (United States)

    Brajnicov, S.; Neacsu, P.; Moldovan, A.; Marascu, V.; Bonciu, A.; Ion, R.; Dinca, V.; Cimpean, A.; Dinescu, M.

    2017-11-01

    Biocompatible and biodegradable coatings with controllable and tailored chemical and physical characteristics (i.e. morphology and roughness) are of great interest in bone related research applications. Within this research direction, in this work, a series of novel biodegradable coatings based on triblock copolymers poly(lactide- co-caprolactone)-block-poly(ethylene-glycol)-block-poly(lactide- co-caprolactone) (PLCL-PEG-PLCL) were obtained by matrix-assisted pulsed laser evaporation (MAPLE) and their morphological characteristics and roughness were modulated by varying target composition and laser fluence. The coatings were used for preliminary in vitro testing with MC3T3-E1 pre-osteoblasts. It was found that for a specific range of fluences, the main functional groups in the MAPLE-deposited thin films, as determined by Fourier transform infrared spectroscopy, are similar to the molecular structures of the initial material. Depending on the deposition parameters, significant changes in morphologies, i.e. material accumulation in the form of droplets, wrinkles, or carpet-like structures were revealed by atomic force microscopy (AFM) and scanning electron microscopy. The optimized coating characteristics were further correlated to MC3T3-E1 pre-osteoblasts response. The ability to control the morphology and to maintain unaltered the chemistry of the deposited material through MAPLE is an important step in creating functional bio-interfaces in the field of biomedical research and tissue engineering.

  12. Biodegradation of thermally treated high-density polyethylene (HDPE) by Klebsiella pneumoniae CH001.

    Science.gov (United States)

    Awasthi, Shraddha; Srivastava, Pratap; Singh, Pardeep; Tiwary, D; Mishra, Pradeep Kumar

    2017-10-01

    Biodegradation of plastics, which are the potential source of environmental pollution, has received a great deal of attention in the recent years. We aim to screen, identify, and characterize a bacterial strain capable of degrading high-density polyethylene (HDPE). In the present study, we studied HDPE biodegradation using a laboratory isolate, which was identified as Klebsiella pneumoniae CH001 (Accession No MF399051). The HDPE film was characterized by Universal Tensile Machine (UTM), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), and Atomic Force Microscope (AFM) before and after microbial incubation. We observed that this strain was capable of adhering strongly on HDPE surface and form a thick biofilm, when incubated in nutrient broth at 30 °C on 120 rpm for 60 days. UTM analysis showed a significant decrease in weight (18.4%) and reduction in tensile strength (60%) of HDPE film. Furthermore, SEM analysis showed the cracks on the HDPE surface, whereas AFM results showed an increase in surface roughness after bacterial incubation. Overall, these results indicate that K. pneumoniae CH001 can be used as potential candidate for HDPE degradation in eco-friendly and sustainable manner in the environment.

  13. 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.

  14. Research regarding biodegradable properties of food polymeric products under microorganism activity

    Science.gov (United States)

    Opran, Constantin; Lazar, Veronica; Fierascu, Radu Claudiu; Ditu, Lia Mara

    2018-02-01

    Aim of this research is the structural analysis by comparison of the biodegradable properties of two polymeric products made by non-biodegradable polymeric material (polypropylene TIPPLEN H949 A) and biodegradable polymeric material (ECOVIO IS 1335), under microorganism activity in order to give the best solution for the manufacture of food packaging biodegradable products. It presents the results of experimental determinations on comparative analysis of tensile strength for the two types of polymers. The sample weight variations after fungal biodegradation activity revealed that, after 3 months, there are no significant changes in polymeric substratum for non-biodegradable polymeric. The microscopically analysis showed that the fungal filaments did not strongly adhered on the non-biodegradable polymeric material, instead, both filamentous fungi strains adhered and covered the surface of the biodegradable sample with germinated filamentous conidia. The spectral analysis of polymer composition revealed that non-biodegradable polymer polypropylene spectra are identical for control and for samples that were exposed to fungal activity, suggesting that this type of sample was not degraded by the fungi strains. Instead, for biodegradable polymer sample, it was observed significant structural changes across multiple absorption bands, suggesting enzyme activity manifested mainly by Aspergillus niger strain. Structural analysis of interdisciplinary research results, lead, to achieving optimal injection molded technology emphasizing technological parameters, in order to obtain food packaging biodegradable products.

  15. Solvent-free biodegradable scleral plugs providing sustained release of vancomycin, amikacin, and dexamethasone--an in vivo study.

    Science.gov (United States)

    Peng, Yi-Jie; Kau, Yi-Chuan; Wen, Chin-Wei; Liu, Kuo-Sheng; Liu, Shih-Jung

    2010-08-01

    Delivering effective drugs at sufficiently high concentrations to the area of infection is a standard treatment for infectious disease, such as endophthalmitis. This is currently done by empirical trans pars plana intravitreal injection of both antibiotics directed against gram-positive and gram-negative microorganisms and steroids. However, injections by needles repeatedly may increase the risks of intraocular infection and hemorrhage, as well as retinal detachment. This article explores the alternative of using biodegradable polymers as scleral plugs for a long-term drug release in vivo. To manufacture plugs, poly(lactide-glycolide) copolymers were first mixed with vancomycin, amikacin, and dexamethasone. The mixture was compressed and sintered at 55 degrees C to form scleral plugs 1.4 mm in diameter. Biodegradable scleral plugs released high concentrations of antibiotics (well above the minimum inhibitory concentrations, MIC) and steroids in vivo for the period of time needed to treat intraocular infection. In addition, no major complications such as infectious or sterile endophthalmitis, retinal detachment, ocular phthisis, or uvea protrusion at sclerotomy site were observed throughout the experiment. The sclerotomy wound healed after total degradation of the scleral implants without leakage or local necrosis. Antibiotic/steroid-impregnated biodegradable scleral plugs may have a potential role in the treatment of various intraocular infections. (c) 2010 Wiley Periodicals, Inc.

  16. Biodegradation of Organic Liquid Waste by Using Consortium Bacteria as Material Preparation of Environmental Pollution Course Textbook

    Directory of Open Access Journals (Sweden)

    Dora Dayu Rahma Turista

    2017-07-01

    Full Text Available Organic waste is one waste type which oftenly pollutes the waters. Biodegradation can be used as an environmental remedy solution that is contaminated by organic matter. This research aimed to determine the ability of bacteria consortium in degrading of organic liquid waste, and construct the textbook for Environmental Pollution subject based on research of biodegradation organic waste by using bacteria consortium. This research was done through two stages. The first stage was an experimental research by using Randomized Complete Designe with bacterial type treatment and 3 repetitions, while the second phase of research was a developmental research from the first stage. The results of the first phase showed that the combination of 3 indigenous isolats bacteria (Enterobacter gergoviae, Vibrio parahaemolyticus, and Pseudomonas stutzeri was the highest potential bacteria in decreasing BOD (71.75% , COD (74.40%, TSS (58.44%, and increasing DO (84.15%. The second phase was Educational Research and Development of teaching materials which refers to the development model of Borg & Gall. The stages of research were: Research and Information Collecting, Planning, Develop Preliminary Form of Product, Preliminary Field Testing and Main Product Revision which was produced as textbook for the Environmental Pollution course entitled Biodegradation Organic Waste by Using Bacteria Consortium.

  17. 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

  18. Assessing the biodegradability of microparticles disposed down the drain.

    Science.gov (United States)

    McDonough, Kathleen; Itrich, Nina; Casteel, Kenneth; Menzies, Jennifer; Williams, Tom; Krivos, Kady; Price, Jason

    2017-05-01

    Microparticles made from naturally occurring materials or biodegradable plastics such as poly(3-hydroxy butyrate)-co-(3-hydroxy valerate), PHBV, are being evaluated as alternatives to microplastics in personal care product applications but limited data is available on their ultimate biodegradability (mineralization) in down the drain environmental compartments. An OECD 301B Ready Biodegradation Test was used to quantify ultimate biodegradability of microparticles made of PHBV foam, jojoba wax, beeswax, rice bran wax, stearyl stearate, blueberry seeds and walnut shells. PHBV polymer was ready biodegradable reaching 65.4 ± 4.1% evolved CO 2 in 5 d and 90.5 ± 3.1% evolved CO 2 in 80 d. PHBV foam microparticles (125-500 μm) were mineralized extensively with >66% CO 2 evolution in 28 d and >82% CO 2 evolution in 80 d. PHBV foam microparticles were mineralized at a similar rate and extent as microparticles made of jojoba wax, beeswax, rice bran wax, and stearyl stearate which reached 84.8  ± 4.8, 84.9  ± 2.2, 82.7  ± 4.7, and 86.4 ± 3.2% CO 2 evolution respectively in 80 d. Blueberry seeds and walnut shells mineralized more slowly only reaching 39.3  ± 6.9 and 5.1 ± 2.8% CO 2 evolution in 80 d respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Preliminary experience with biodegradable implants for fracture fixation

    Directory of Open Access Journals (Sweden)

    Dhillon Mandeep

    2008-01-01

    Full Text Available Background: Biodegradable implants were designed to overcome the disadvantages of metal-based internal fixation devices. Although they have been in use for four decades internationally, many surgeons in India continue to be skeptical about the mechanical strength of biodegradable implants, hence this study. Materials and Methods: A prospective study was done to assess the feasibility and surgeon confidence level with biodegradable implants over a 12-month period in an Indian hospital. Fifteen fractures (intra-articular, metaphyseal or small bone fractures were fixed with biodegradable implants. The surgeries were randomly scheduled so that different surgeons with different levels of experience could use the implants for fixation. Results: Three fractures (one humeral condyle, two capitulum, were supplemented by additional K-wires fixation. Trans-articular fixator was applied in two distal radius and two pilon fractures where bio-pins alone were used. All fractures united, but in two cases the fracture displaced partially during the healing phase; one fibula due to early walking, and one radius was deemed unstable even after bio-pin and external fixator. Conclusions: Biodegradable -implants are excellent for carefully selected cases of intra-articular fractures and some small bone fractures. However, limitations for use in long bone fractures persist and no great advantage is gained if a "hybrid" composite is employed. The mechanical properties of biopins and screws in isolation are perceived to be inferior to those of conventional metal implants, leading to low confidence levels regarding the stability of reduced fractures; these implants should be used predominantly in fracture patterns in which internal fixation is subjected to minimal stress.

  20. Biodegradation of 4-nitroaniline by plant-growth promoting Acinetobacter sp. AVLB2 and toxicological analysis of its biodegradation metabolites

    Energy Technology Data Exchange (ETDEWEB)

    Silambarasan, Sivagnanam [Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Vangnai, Alisa S., E-mail: alisa.v@chula.ac.th [Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok 10330 (Thailand)

    2016-01-25

    Highlights: • Acinetobacter sp. AVLB2 is a PGPB able to degrade high concentration of 4-NA. • Growth and degradation kinetics for 4-NA removal by AVLB2 were studied. • A novel biodegradation pathway for 4-nitroaniline has been proposed. • Toxicological studies revealed non-toxic nature of 4-NA biodegraded metabolites. • Acinetobacter sp. AVLB2 could maintain PGP traits under 4-NA stress. - Abstract: 4-nitroaniline (4-NA) is one of the major priority pollutants generated from industrial productions and pesticide transformation; however very limited biodegradation details have been reported. This work is the first to report 4-NA biodegradation kinetics and toxicity reduction using a newly isolated plant-growth promoting bacterium, Acinetobacter sp. AVLB2. The 4-NA-dependent growth kinetics parameters: μ{sub max}, K{sub s} and K{sub i}, were determined to be 0.039 h{sup −1}, 6.623 mg L{sup −1} and 25.57 mg L{sup −1}, respectively using Haldane inhibition model, while the maximum biodegradation rate (V{sub max}) of 4-NA was at 0.541 mg L{sup −1} h{sup −1} and 0.551 mg L{sup −1} h{sup −1}, following Michaelis–Menten and Hanes–Woolf models, respectively. Biodegradation pathway of 4-NA by Acinetobacter sp. AVLB2 was proposed, and successfully led to the reduction of 4-NA toxicity according to the following toxicity assessments: microbial toxicity using Escherichia coli DH5α, phytotoxicity with Vigna radiata and Crotalaria juncea, and cytogenotoxicity with Allium cepa root-tip cells. In addition, Acinetobacter sp. AVLB2 possess important plant-growth promoting traits, both in the presence and absence of 4-NA. This study has provided a new insight into 4-NA biodegradation ability and concurrent plant-growth promoting activities of Acinetobacter sp. AVLB2, which may indicate its potential role for rhizoremediation, while sustaining crop production even under 4-NA stressed environment.

  1. Petroleum-hydrocarbons biodegradation by Pseudomonas strains ...

    African Journals Online (AJOL)

    The capability of these isolates to degrade petroleum was performed by measuring the optical density, colony forming unit counts (CFU/ml) and concentration of total petroleum hydrocarbons (TPH). Degradation of Isomerate by these isolates was analyzed by gas chromatography with flame ionization detector (FID). Results ...

  2. 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.

  3. 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

  4. 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

  5. Contributor Form

    Directory of Open Access Journals (Sweden)

    Chief Editor

    2014-09-01

    to produce preprints or reprints and translate into languages other than English for sale or free distribution; and 4 the right to republish the work in a collection of articles in any other mechanical or electronic format. We give the rights to the corresponding author to make necessary changes as per the request of the journal, do the rest of the correspondence on our behalf and he/she will act as the guarantor for the manuscript on our behalf. All persons who have made substantial contributions to the work reported in the manuscript, but who are not contributors, are named in the Acknowledgment and have given me/us their written permission to be named. If I/we do not include an Acknowledgment that means I/we have not received substantial contributions from non-contributors and no contributor has been omitted.S NoAuthors' NamesContribution (IJCME Guidelines{1 substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; 2 drafting the article or revising it critically for important intellectual content; and 3 final approval of the version to be published. Authors should meet conditions 1, 2, and 3}.SignatureDate                              Note: All the authors are required to sign independently in this form in the sequence given above. In case an author has left the institution/country and whose whereabouts are not known, the senior author may sign on his/her behalf taking the responsibility.No addition/deletion/ or any change in the sequence of the authorship will be permissible at a later stage, without valid reasons and permission of the Editor.If the authorship is contested at any stage, the article will be either returned or will not be processed for publication till the issue is solved.Maximum up to 4 authors for short communication and up to 6 authors for original article.

  6. Contributors Form

    Directory of Open Access Journals (Sweden)

    Chief Editor

    2016-06-01

    to produce preprints or reprints and translate into languages other than English for sale or free distribution; and 4 the right to republish the work in a collection of articles in any other mechanical or electronic format. We give the rights to the corresponding author to make necessary changes as per the request of the journal, do the rest of the correspondence on our behalf and he/she will act as the guarantor for the manuscript on our behalf. All persons who have made substantial contributions to the work reported in the manuscript, but who are not contributors, are named in the Acknowledgment and have given me/us their written permission to be named. If I/we do not include an Acknowledgment that means I/we have not received substantial contributions from non-contributors and no contributor has been omitted.S NoAuthors' NamesContribution (IJCME Guidelines{1 substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; 2 drafting the article or revising it critically for important intellectual content; and 3 final approval of the version to be published. Authors should meet conditions 1, 2, and 3}.SignatureDate                              Note: All the authors are required to sign independently in this form in the sequence given above. In case an author has left the institution/country and whose whereabouts are not known, the senior author may sign on his/her behalf taking the responsibility.No addition/deletion/ or any change in the sequence of the authorship will be permissible at a later stage, without valid reasons and permission of the Editor.If the authorship is contested at any stage, the article will be either returned or will not be processed for publication till the issue is solved.Maximum up to 4 authors for short communication and up to 6 authors for original article.

  7. In vivo biodegradation of colloidal quantum dots by a freshwater invertebrate, Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Dongwook; Kim, Min Jung; Park, Chansik; Park, Jaehong [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); Choi, Kyungho [Department of Environmental Health, Seoul National University, Seoul 151-742 (Korea, Republic of); Yoon, Tae Hyun, E-mail: thyoon@gmail.com [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2012-06-15

    Impacts of planktonic invertebrate, Daphnia magna, on the speciation of colloidal quantum dots (QD) were investigated using fluorescence spectromicroscopic technique. Well-dispersed {sup GA/TOPO}QD were prepared by forming a supramolecular assembly of hydrophobic {sup TOPO}QD with biomacromolecules (i.e., Gum Arabic, GA). Biological degradation of this nanomaterial was monitored by fluorescence spectromicroscopic methods. Our study confirmed the major uptake pathway of manufactured nanomaterials and in vivo biodegradation processes in a well-known toxicity test organism, D. magna. In addition, we also found that D. magna can induce significant deterioration of aquatic media by releasing fragments of partially degraded QD colloids. These biological processes may significantly change the predicted toxicities of nanomaterials in aquatic environments. Thus, we propose that the impacts of aquatic living organisms on the environmental fate of manufactured nanomaterials (MNs) should be carefully taken into account when assessing the risk of MNs to the environment and human health.

  8. 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.

  9. Coatings and Biodegradable and Bioabsorbable Films

    Science.gov (United States)

    2006-09-01

    K.A., "Novel Method for Characterization of Poly(D,L-lactide) Degradation Based on Dielectric Spectroscopy ," Polymers for Biomedical Applications ...consumption of Temperature (°C) hydroxyl groups upon cross-linking with HDI. The Figl2. Positron annihilation assessment hydroxyl groups are known to form...higher Tg, the larger none-equilibrium 0 1.26 A 0 volume is accumulated upon cooling. Probing free- A volume with positron life time spectroscopy 1.25

  10. 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

  11. Application of a Biodegradable Lubricant in a Diesel Vehicle

    DEFF Research Database (Denmark)

    Schramm, Jesper

    2003-01-01

    The IEA Advanced Motor Fuels Agreement has initiated this project concerning the application of biodegradable lubricants to diesel and gasoline type vehicles. Emission measurements on a chassis dynamometer were carried out. The purpose of these measurements was to compare the emissions of CO, CO2......, NOx, THC, PM, lubricant-SOF and PAH from one diesel and one gasoline type vehicle using biodegradable lubricants and conventional lubricants. This paper describes the results of the experiments with the diesel type vehicle only. Lubricant consumption and fuel consumption are other important parameters...... that have been evaluated during the experiments. Both vehicle types were operated on conventional crude oil based fuels and alternative fuels. The diesel vehicle was operated on conventional diesel fuel from a Danish fuel station, low sulfur diesel from Sweden and biodiesel, which was bought at a fuel...

  12. Biodegradation of poly(ε-caprolactone in natural water environments

    Directory of Open Access Journals (Sweden)

    Heimowska Aleksandra

    2017-03-01

    Full Text Available The environmental degradation of poly(ε-caprolactone[PCL] in natural fresh water (pond and in The Baltic Sea is presented in this paper. The characteristic parameters of both environments were measured during experiment and their influence on the biodegradation of the samples was discussed. The loss of weight and changes of surface morphology of polymer samples were tested during the period of incubation. The poly(ε-caprolactone was more biodegradable in natural sea water than in pond. PCL samples were completely assimilated over the period of six weeks incubation in The Baltic Sea water, but after forty two weeks incubation in natural fresh water the polymer weight loss was about 39%. The results have confirmed that the investigated polymers are susceptible to an enzymatic attack of microorganisms, but their activity depends on environments.

  13. Parallel pathways of ethoxylated alcohol biodegradation under aerobic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zembrzuska, Joanna, E-mail: Joanna.Zembrzuska@put.poznan.pl; Budnik, Irena, E-mail: Irena.Budnik@gmail.com; Lukaszewski, Zenon, E-mail: zenon.lukaszewski@put.poznan.pl

    2016-07-01

    Non-ionic surfactants (NS) are a major component of the surfactant flux discharged into surface water, and alcohol ethoxylates (AE) are the major component of this flux. Therefore, biodegradation pathways of AE deserve more thorough investigation. The aim of this work was to investigate the stages of biodegradation of homogeneous oxyethylated dodecanol C{sub 12}E{sub 9} having 9 oxyethylene subunits, under aerobic conditions. Enterobacter strain Z3 bacteria were chosen as biodegrading organisms under conditions with C{sub 12}E{sub 9} as the sole source of organic carbon. Bacterial consortia of river water were used in a parallel test as an inoculum for comparison. The LC-MS technique was used to identify the products of biodegradation. Liquid-liquid extraction with ethyl acetate was selected for the isolation of C{sub 12}E{sub 9} and metabolites from the biodegradation broth. The LC-MS/MS technique operating in the multiple reaction monitoring (MRM) mode was used for quantitative determination of C{sub 12}E{sub 9}, C{sub 12}E{sub 8}, C{sub 12}E{sub 7} and C{sub 12}E{sub 6}. Apart from the substrate, the homologues C{sub 12}E{sub 8}, C{sub 12}E{sub 7} and C{sub 12}E{sub 6}, being metabolites of C{sub 12}E{sub 9} biodegradation by shortening of the oxyethylene chain, as well as intermediate metabolites having a carboxyl end group in the oxyethylene chain (C{sub 12}E{sub 8}COOH, C{sub 12}E{sub 7}COOH, C{sub 12}E{sub 6}COOH and C{sub 12}E{sub 5}COOH), were identified. Poly(ethylene glycols) (E) having 9, 8 and 7 oxyethylene subunits were also identified, indicating parallel central fission of C{sub 12}E{sub 9} and its metabolites. Similar results were obtained with river water as inoculum. It is concluded that AE, under aerobic conditions, are biodegraded via two parallel pathways: by central fission with the formation of PEG, and by Ω-oxidation of the oxyethylene chain with the formation of carboxylated AE and subsequent shortening of the oxyethylene chain by a

  14. 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

  15. Effects of external stress on biodegradable orthopedic materials: A review

    Directory of Open Access Journals (Sweden)

    Xuan Li

    2016-09-01

    Full Text Available Biodegradable orthopedic materials (BOMs are used in rehabilitation and reconstruction of fractured tissues. The response of BOMs to the combined action of physiological stress and corrosion is an important issue in vivo since stress-assisted degradation and cracking are common. Although the degradation behavior and kinetics of BOMs have been investigated under static conditions, stress effects can be very serious and even fatal in the dynamic physiological environment. Since stress is unavoidable in biomedical applications of BOMs, recent work has focused on the evaluation and prediction of the properties of BOMs under stress in corrosive media. This article reviews recent progress in this important area focusing on biodegradable metals, polymers, and ceramics.

  16. Biodegradability of leachates from Chinese and German municipal solid waste

    Institute of Scientific and Technical Information of China (English)

    SELIC E.; WANG Chi; BOES N., HERBELL J.D.

    2007-01-01

    The quantitative and qualitative composition of Chinese municipal solid waste (MSW) differs significantly from German waste. The focus of this paper is on whether these differences also lead to dissimilar qualities of leachates during storage or landfilling. Leachates ingredients determine the appropriate treatment technique. MSW compositions of the two cities Guilin (China) and Essen (Germany), each with approx. 600000 inhabitants, are used to simulate Chinese and German MSW types. A sequencing batch reactor (SBR) is used, combining aerobic and anaerobic reaction principles, to test the biodegradability of leachates. Leachates are tested for temperature, pH-value, redox potentials, and oxygen concentration. Chemical oxygen demand (COD) values are determined. Within 8 h, the biodegradation rates for both kinds of leachates are more than 90%. Due to the high organic content of Chinese waste, the degradation rate for Guilin MSW leachate is even higher, up to 97%. The effluent from SBR technique is suitable for direct discharge into bodies of water.

  17. Biodegradation of Carbon Nanotubes, Graphene, and Their Derivatives.

    Science.gov (United States)

    Chen, Ming; Qin, Xiaosheng; Zeng, Guangming

    2017-09-01

    Carbon nanotubes (CNTs), graphene (GRA), and their derivatives are promising materials for a wide range of applications such as pollutant removal, enzyme immobilization, bioimaging, biosensors, and drug delivery and are rapidly increasing in use and increasingly mass produced. The biodegradation of carbon nanomaterials by microbes and enzymes is now of great importance for both reducing their toxicity to living organisms and removing them from the environment. Here we review recent progress in the biodegradation field from the point of view of the primary microbes and enzymes that can degrade these nanomaterials, along with experimental and molecular simulation methods for the exploration of nanomaterial degradation. Further efforts should primarily aim toward expanding the repertoire of microbes and enzymes and exploring optimal conditions for the degradation of nanomaterials. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Anaerobic biodegradation of spent sulphite liquor in a UASB reactor

    DEFF Research Database (Denmark)

    Jantsch, T.G.; Angelidaki, Irini; Schmidt, Jens Ejbye

    2002-01-01

    Anaerobic biodegradation of fermented spent sulphite liquor, SSL, which is produced during the manufacture of sulphite pulp, was investigated. SSL contains a high concentration of lignin products in addition to hemicellulose and has a very high COD load (173 g COD l1). Batch experiments...... ðl dÞ1 and hydraulic retention time from 3.7 to 1.5 days. The biogas productivity was 3 l ðlreactor dÞ1, with a yield of 0.05 l gas ðg VSÞ1. These results suggest that anaerobic digestion in UASB reactors may provide a new alternative for the treatment of SSL to other treatment strategies...... such as incineration. Although the total COD reduction achieved is limited, bioenergy is produced and readily biodegradable matter is removed causing less load on post-treatment installations. 2002 Elsevier Science Ltd. All rights reserved....

  19. Evaluation of biodegradable plastics for rubber seedling applications

    Science.gov (United States)

    Mansor, Mohd Khairulniza; Dayang Habibah A. I., H.; Kamal, Mazlina Mustafa

    2015-08-01

    The main negative consequence of conventional plastics in agriculture is related to handling the wastes plasticand the associated environmental impact. Hence, a study of different types of potentially biodegradable plastics used for nursery applications have been evaluated on its mechanical,water absorption propertiesand Fourier transform infra-red (FTIR) spectroscopy. Supplied samples from different companies were designated as SF, CF and CO. Most of the polybags exhibited mechanical properties quite similar to the conventional plastics (polybag LDPE). CO polybag which is based on PVA however had extensively higher tensile strength and water absorption properties. FTIR study revealed a characteristics absorbance of conventional plastic, SF, CF and CO biodegradable polybag are associated with polyethylene, poly(butylene adipate-co-terephthalate) (PBAT), polyethylene and polyvinyl alcohol (PVA) structures respectively.

  20. Application of biodegradable plates for treating pediatric mandibular fractures.

    Science.gov (United States)

    An, Jingang; Jia, Pengcheng; Zhang, Yi; Gong, Xi; Han, Xiaodong; He, Yang

    2015-05-01

    We assessed the clinical results of a biodegradable plate system for the internal fixation of mandibular fractures in children, and observed the imaging features of fracture healing and bone changes around the biodegradable plates and screws during follow-up. We enrolled 39 patients (22 male, 17 female, average age 4 years 10 months) with different mandibular fractures. We used 2.0-mm resorbable plates to repair the fractures. Postoperative follow-up ranged from 6 months to 5 years; average follow-up was 1 year 2 months. The outcome measures identified and assessed included facial symmetry, mouth opening, occlusal relationship, infection, nonunion, malunion, and plate dehiscence. We fixed 42 fractures with 43 resorbable plates; the fracture site of one patient (aged 11 years 3 months) was fixed with two plates. Two patients developed small fistulas at the intraoral incision 2 months after surgery; the fistulas healed after 1 month without special treatment. In the other patients, the incision healed well, there was facial symmetry, mouth opening was >35 mm, and occlusion was good. Follow-up computed tomography examination data were available for 20 cases, and revealed different degrees of radiolucency indicating that osteolysis had occurred. Radiolucency was observed around the resorbable plates 1 month after the surgery. The extent and depth of the radiolucent region were obvious within 1 year of surgery. In the second year, there were obvious repairs, with the bony defect areas becoming shallower. After 2 years, the bony defect areas had almost disappeared. Biodegradable fixation devices are safe and efficient for treating pediatric mandibular fractures. Osteolysis commonly follows biodegradable fixation of pediatric mandibular fractures, and has no adverse effect on fracture healing. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  1. Biodegradation at Dynamic Plume Fringes: Mixing Versus Reaction Control

    Science.gov (United States)

    Cirpka, O. A.; Eckert, D.; Griebler, C.; Haberer, C.; Kürzinger, P.; Bauer, R.; Mellage, A.

    2014-12-01

    Biodegradation of continuously emitted plumes is known to be most pronounced at the plume fringe, where mixing of contaminated water and ambient groundwater, containing dissolved electron acceptors, stimulates microbial activity. Under steady-state conditions, physical mixing of contaminant and electron acceptor by transverse dispersion was shown to be the major bottleneck for biodegradation, with plume lengths scaling inversely with the bulk transverse dispersivity in quasi two-dimensional settings. Under these conditions, the presence of suitable microbes is essential but the biokinetic parameters do not play an important role. When the location of the plume shifts (caused, e.g., by a fluctuating groundwater table), however, the bacteria are no more situated at the plume fringe and biomass growth, decay, activation and deactivation determine the time lag until the fringe-controlled steady state is approached again. During this time lag, degradation is incomplete. The objective of the presented study was to analyze to which extent flow and transport dynamics diminish effectiveness of fringe-controlled biodegradation and which microbial processes and related biokinetic parameters determine the system response in overall degradation to hydraulic fluctuations. We performed experiments in quasi-two-dimensional flow through microcosms on aerobic toluene degradation by Pseudomonas putida F1. Plume dynamics were simulated by vertical alteration of the toluene plume position and experimental results were analyzed by reactive-transport modeling. We found that, even after disappearance of the toluene plume for two weeks, the majority of microorganisms stayed attached to the sediment and regained their full biodegradation potential within two days after reappearance of the toluene plume. Our results underline that besides microbial growth and maintenance (often subsumed as "biomass decay") microbial dormancy (that is, change into a metabolically inactive state) and

  2. Biodegradation studies of oil sludge containing high hydrocarbons concentration

    International Nuclear Information System (INIS)

    Olguin-Lora, P.; Munoz-Colunga, A.; Castorena-Cortes, G.; Roldan-Carrillo, T.; Quej Ake, L.; Reyes-Avila, J.; Zapata-Penasco, I.; Marin-Cruz, J.

    2009-01-01

    Oil industry has a significant impact on environment due to the emission of, dust, gases, waste water and solids generated during oil production all the way to basic petrochemical product manufacturing stages. the aim of this work was to evaluate the biodegradation of sludge containing high hydrocarbon concentration originated by a petroleum facility. A sludge sampling was done at the oil residuals pool (ORP) on a gas processing center. (Author)

  3. Obtaining nanofibers from sisal to reinforce nanocomposites biodegradable matrixes

    International Nuclear Information System (INIS)

    Oliveira, Francieli B. de; Teixeira, Eliangela de M.; Marconcini, Jose M.; Mattoso, Luiz H.C.; Teodoro, Kelcilene B.R.

    2009-01-01

    Cellulose nanofibers have been extracted by acid hydrolysis from sisal fibers. They are seen a good source material due to availability and low cost. The nanofibers was evaluated by thermal degradation behavior using thermogravimetry (TG), crystallinity by X-ray diffraction and morphological structure was investigated by atomic force microscopy (AFM) experiments. The resulting nanofibers was shown high crystallinity and a network of rodlike cellulose elements. The nanofibers will be incorporated as reinforcement in a biodegradable matrix and evaluated. (author)

  4. 3D-Printed Biodegradable Polymeric Vascular Grafts.

    Science.gov (United States)

    Melchiorri, A J; Hibino, N; Best, C A; Yi, T; Lee, Y U; Kraynak, C A; Kimerer, L K; Krieger, A; Kim, P; Breuer, C K; Fisher, J P

    2016-02-04

    Congenital heart defect interventions may benefit from the fabrication of patient-specific vascular grafts because of the wide array of anatomies present in children with cardiovascular defects. 3D printing is used to establish a platform for the production of custom vascular grafts, which are biodegradable, mechanically compatible with vascular tissues, and support neotissue formation and growth. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. 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.

  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

  7. Application of wheat B-starch in biodegradable plastic materials

    Czech Academy of Sciences Publication Activity Database

    Šárka, E.; Kruliš, Zdeněk; Kotek, Jiří; Růžek, L.; Korbářová, A.; Bubník, Z.; Růžková, M.

    2011-01-01

    Roč. 29, č. 3 (2011), s. 232-242 ISSN 1212-1800 R&D Projects: GA ČR GA525/09/0607 Institutional research plan: CEZ:AV0Z40500505 Keywords : biodegradable plastic * polycaprolactone * B-starch Subject RIV: JI - Composite Materials Impact factor: 0.522, year: 2011 http://www.agriculturejournals.cz/publicFiles/39918.pdf

  8. Biodegradable bags for the production of plant seedlings

    OpenAIRE

    Bilck,Ana Paula; Olivato,Juliana Bonametti; Yamashita,Fabio; Souza,José Roberto Pinto de

    2014-01-01

    The production of plant seedlings has traditionally used polyethylene bags, which are thrown out in the soil or burned after transplant because the large amount of organic material attached to the bags makes recycling difficult. Additionally, when a seedling is taken from the bag for transplant, there is the risk of root damage, which compromises the plant’s development. In this study, we developed biodegradable bags to be used in seedling production, and we verify their influence on the deve...

  9. Role of different biodegradable polymers on the permeability of ciprofloxacin

    OpenAIRE

    Chakraborti, Chandra Kanti; Sahoo, Subhashree; Behera, Pradipta Kumar

    2014-01-01

    Since permeability across biological membranes is a key factor in the absorption and distribution of drugs, drug permeation characteristics of three oral suspensions of ciprofloxacin were designed and compared. The three suspensions of ciprofloxacin were prepared by taking biodegradable polymers such as carbopol 934, carbopol 940, and hydroxypropyl methylcellulose (HPMC). The permeability study was performed by using a Franz diffusion cell through both synthetic cellulose acetate membrane and...

  10. Micro fabrication of biodegradable polymer drug delivery devices

    DEFF Research Database (Denmark)

    Nagstrup, Johan

    The pharmaceutical industry is presently facing several obstacles in developing oral drug delivery systems. This is primarily due to the nature of the discovered drug candidates. The discovered drugs often have poor solubility and low permeability across the gastro intestinal epithelium. Furtherm......The pharmaceutical industry is presently facing several obstacles in developing oral drug delivery systems. This is primarily due to the nature of the discovered drug candidates. The discovered drugs often have poor solubility and low permeability across the gastro intestinal epithelium...... permeability and degradation. These systems are for the majority based on traditional materials used in micro technology, such as SU-8, silicon, poly(methyl methacrylate). The next step in developing these new drug delivery systems is to replace classical micro fabrication materials with biodegradable polymers....... In order to successfully do this, methods for fabricating micro structures in biodegradable polymers need to be developed. The goal of this project has been to develop methods for micro fabrication in biodegradable polymers and to use these methods to produce micro systems for oral drug delivery. This has...

  11. 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

  12. 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.

  13. Assessing the toxicity and biodegradability of deep eutectic solvents.

    Science.gov (United States)

    Wen, Qing; Chen, Jing-Xin; Tang, Yu-Lin; Wang, Juan; Yang, Zhen

    2015-08-01

    Deep eutectic solvents (DESs) have emerged as a new type of promising ionic solvents with a broad range of potential applications. Although their ecotoxicological profile is still poorly known, DESs are generally regarded as "green" because they are composed of ammonium salts and H-bond donors (HBDs) which are considered to be eco-friendly. In this work, cholinium-based DESs comprised of choline chloride (ChCl) and choline acetate (ChAc) as the salt and urea (U), acetamide (A), glycerol (G) and ethylene glycol (EG) as the HBD were evaluated for their toxic effects on different living organisms such as Escherichia coli (a bacterium), Allium sativum (garlic, a plant) and hydra (an invertebrate), and their biodegradabilities were assessed by means of closed bottle tests. These DESs possessed an anti-bacterial property and exhibited inhibitory effects on the test organisms adopted, depending on the composition and concentration of the DES. The mechanism for the impact of DESs and their components on different living organisms can be associated to their interactions with the cellular membranes. Not all DESs can be considered readily biodegradable. By extending the limited knowledge about the toxicity and biodegradation of this particular solvent family, this investigation on DESs provides insight into our structure-based understanding of their ecotoxicological behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Viability of biocompatible and biodegradable seeds production with incorporated radionuclides

    International Nuclear Information System (INIS)

    Roberto, W.S.; Pereira, M.M.; Vasconcelos, W.L.; Campos, T.P.R.

    2000-01-01

    The present work aims the development of radioactive seeds, biocompatible and biodegradable, with the objective of adding options in the cancer treatment. The work focus on the production of seeds biodegradable that incorporate radioisotopes with half life inferior than the degradation time of the material. The idea of producing devices with biodegradable materials impregnated with radioisotopes of short half life will offer new possibilities in the cancer treatment, since they can be used following the same procedures of the permanent interstitial brachytherapy, but using degradable materials compatible with the physiological environment. It will be discussed in particular the possible application of these seeds in the treatment of prostate cancer. A review of the subject and a preliminary evaluation of the viability of production of the seeds will be presented. The method of production of the seeds is based on the incorporation of Iodine and Samarium in glass matrixes obtained by sol-gel processing. X-ray fluorescence was done in the samples produced and the incorporation of Iodine and Samarium atoms was confirmed. (author)

  15. 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.

  16. Slurry-phase biodegradation of weathered oily sludge waste.

    Science.gov (United States)

    Machín-Ramírez, C; Okoh, A I; Morales, D; Mayolo-Deloisa, K; Quintero, R; Trejo-Hernández, M R

    2008-01-01

    We assessed the biodegradation of a typical oily sludge waste (PB401) in Mexico using several regimes of indigenous microbial consortium and relevant bioremediation strategies in slurry-phase system. Abiotic loss of total petroleum hydrocarbons (TPH) in the PB401 was insignificant, and degradation rates under the various treatment conditions ranged between 666.9 and 2168.7 mg kg(-1) day(-1) over a 15 days reaction period, while viable cell count peaked at between log(10)5.7 and log(10)7.4 cfu g(-1). Biostimulation with a commercial fertilizer resulted in 24% biodegradation of the TPH in the oily waste and a corresponding peak cell density of log(10)7.4 cfu g(-1). Addition of non-indigenous adapted consortium did not appear to enhance the removal of TPH from the oily waste. It would appear that the complexities of the components of the alkylaromatic fraction of the waste limited biodegradation rate even in a slurry system.

  17. Effect of temperature on biodegradation of crude oil

    International Nuclear Information System (INIS)

    Zekri, A.; Chaalal, O.

    2005-01-01

    An active strain of anaerobic thermophilic bacteria was isolated from the environment of the United Arab Emirates. This project studied the effect of temperature, salinity and oil concentration on biodegradation of crude oil. Oil weight loss, microbial growth and the changes of the crude oil asphaltene concentration are used to evaluate the oil degradation by this strain. A series of batch experiments was performed to study the effects of bacteria on the degradation of crude oil. The effects of oil concentration, bacteria concentration, temperature and salinity on the biodegradation were investigated. The temperatures of the studied systems were varied between 35 and 75 o C and the salt concentrations were varied between 0 and 10%. Oil concentrations were ranged from 5 to 50% by volume. Experimental work showed the bacteria employed in this project were capable of surviving the harsh environment and degrading the crude oil at various conditions. Increasing the temperature increases the rate of oil degradation by bacteria. Increasing the oil concentration in general decreases the rate of bacteria oil degradation. Salinity plays a major role on the acceleration of biodegradation process of crude oil. An optimum salinity should be determined for every studied system. The finding of this project could be used in either the treatment of oil spill or in-situ stimulation of heavy oil wells. (author)

  18. 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

  19. Biodegradation of the High Explosive Hexanitrohexaazaiso-wurtzitane (CL-20

    Directory of Open Access Journals (Sweden)

    Steve Nicolich

    2009-04-01

    Full Text Available The aerobic biodegradability of the high explosive CL-20 by activated sludge and the white rot fungus Phanerochaete chrysosporium has been investigated. Although activated sludge is not effective in degrading CL-20 directly, it can mineralize the alkaline hydrolysis products. Phanerochaete chrysosporium degrades CL-20 in the presence of supplementary carbon and nitrogen sources. Biodegradation studies were conducted using various nutrient media under diverse conditions. Variables included the CL-20 concentration; levels of carbon (as glycerol and ammonium sulfate and yeast extract as sources of nitrogen. Cultures that received CL-20 at the time of inoculation transformed CL-20 completely under all nutrient conditions studied. When CL-20 was added to pre-grown cultures, degradation was limited. The extent of mineralization was monitored by the 14CO2 time evolution; up to 51% mineralization was achieved when the fungus was incubated with [14C]-CL-20. The kinetics of CL-20 biodegradation by Phanerochaete chrysosporium follows the logistic kinetic growth model.

  20. Estimating the Biodegradation Kinetics by Mixed Culture Degrading Pyrene (Pyr

    Directory of Open Access Journals (Sweden)

    B. S. U. Ibn Abubakar

    2017-02-01

    Full Text Available Biodegradation and kinetics of Pyrene (Pyr degradation by a mixed culture previously isolated from hydrocarbon-polluted soil were conducted. Preliminary investigation on environmental factors affecting the degradation of Pyr such as temperature, pH and concentrations of Pyr was performed. These factors were optimised and established in aqueous experiments. In order to develop kinetics of Pyr degradation, an optimum temperature of 30oC and pH of 7.0 was used. Biodegradation kinetics was carried out, at first, using higher concentration between (100-700 ppm as sole source of carbon in mineral salt medium (MSM supplemented with 0.1% yeast extract. The result indicated that a range of concentration between (100-700 ppm inhibits the performance of the mixed culture. A concentration range between (10-100 ppm did not inhibit the growth of the mixed culture. A First-order rate constant, k was higher (0.0487 mg/lh with a substrate concentration of 20 ppm than other concentrations. The average degradation rate constant is 0.0029 mg/Lh for all the concentrations tested. This indicated that the mixed culture could degrade over 0.0696 ppm of Pyr per day. It also confirmed that kinetics of microbial degradation was partially fitted into Monod model. The data can be used to estimate biodegradation of Pyr by a mixed culture and preliminarily estimation of degradation rates.

  1. Fully Biodegradable Biocomposites with High Chicken Feather Content

    Directory of Open Access Journals (Sweden)

    Ibon Aranberri

    2017-11-01

    Full Text Available The aim of this work was to develop new biodegradable polymeric materials with high loadings of chicken feather (CF. In this study, the effect of CF concentration and the type of biodegradable matrix on the physical, mechanical and thermal properties of the biocomposites was investigated. The selected biopolymers were polylactic acid (PLA, polybutyrate adipate terephthalate (PBAT and a PLA/thermoplastic copolyester blend. The studied biocomposites were manufactured with a torque rheometer having a CF content of 50 and 60 wt %. Due to the low tensile strength of CFs, the resulting materials were penalized in terms of mechanical properties. However, high-loading CF biocomposites resulted in lightweight and thermal-insulating materials when compared with neat bioplastics. Additionally, the adhesion between CFs and the PLA matrix was also investigated and a significant improvement of the wettability of the feathers was obtained with the alkali treatment of the CFs and the addition of a plasticizer like polyethylene glycol (PEG. Considering all the properties, these 100% fully biodegradable biocomposites could be adequate for panel components, flooring or building materials as an alternative to wood–plastic composites, contributing to the valorisation of chicken feather waste as a renewable material.

  2. 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.

  3. 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.

  4. Preliminary Ecotoxicity and Biodegradability Assessment of Metalworking Fluids

    Science.gov (United States)

    Gerulová, Kristína; Amcha, Peter; Filická, Slávka

    2010-01-01

    The main aim of this study was to evaluate the potential of activated sludge from sewage treatment plant to degrade selected MWFs (ecotoxicity to bacterial consortium) and to evaluate the ecotoxicity by Lemna minor-higher plant. After evaluating the ecotoxicity, biodegradations rate with activated sludge was assessed on the basis of COD measurement. Preliminary study of measuring the ecotoxicity according to OECD 221 by Lemna minor shows effective concentration of Emulzin H at the rate of 81.6 mg l-1, for Ecocool 82.9 mg l-1, for BC 25 about 99.3 mg l-1, and for Dasnobor about 97.3 mg l-1. Preliminary study of measuring the ecotoxicity by bacterial consortium according to OECD 209 (STN EN ISO 8192) shows effective concentration of Blasocut BC 25 at the rate 227.4 mg l-1. According to OECD 302B, the biodegradations level of Emulzin H, Ecocool and BC 25 achieved 80% in 10 days. It can be stated that these MWFs have potential to ultimate degradation, but the statement has to be confirmed by a biodegradability test with other parameters than COD, which exhibits some disadvantages in testing O/W emulsions.

  5. Analysis of proteins involved in biodegradation of crop biomass

    Science.gov (United States)

    Crawford, Kamau; Trotman, Audrey

    1998-01-01

    The biodegradation of crop biomass for re-use in crop production is part of the bioregenerative life support concept proposed by the National Aeronautics and Space Administration (NASA) for long duration, manned space exploration. The current research was conducted in the laboratory to evaluate the use of electrophoretic analysis as a means of rapidly assaying for constitutive and induced proteins associated with the bacterial degradation of crop residue. The proteins involved in crop biomass biodegradation are either constitutive or induced. As a result, effluent and cultures were examined to investigate the potential of using electrophoretic techniques as a means of monitoring the biodegradation process. Protein concentration for optimum banding patterns was determined using the Bio-Rad Protein Assay kit. Four bacterial soil isolates were obtained from the G.W. Carver research Farm at Tuskegee University and used in the decomposition of components of plant biomass. The culture, WDSt3A was inoculated into 500 mL of either Tryptic Soy Broth or Nutrient Broth. Incubation, with shaking of each flask was for 96 hours at 30 C. The cultures consistently gave unique banding patterns under denaturing protein electrophoresis conditions, The associated extracellular enzymes also yielded characteristic banding patterns over a 14-day period, when native electrophoresis techniques were used to examine effluent from batch culture bioreactors. The current study evaluated sample preparation and staining protocols to determine the ease of use, reproducibility and reliability, as well as the potential for automation.

  6. Anaerobic biodegradability and toxicity of complex or toxicant wastewater

    International Nuclear Information System (INIS)

    Wills Betancur, B.A.

    1995-01-01

    As a first approximation to wastewater classification in susceptibility terms to treatment by anaerobic biological system, anaerobic biodegradability trials are accomplished to leached of sanitary landfill, to wastewater of coffee grain wet treatment plant and to wastewater of fumaric acid recuperation plant. In the last Plant, anaerobic toxicity trials and lethal toxicity on the Daphnia pulex micro-crustacean are made too. Anaerobic biological trials are made continuing the Wageningen University (Holland) Methodology (1.987). Lethal toxicity biological trials are made following the Standard Methods for the Examination of Water and Wastewater(18th edition, 1992). In development of this investigation project is found that fumaric acid recuperation plant leached it has a low anaerobic biodegradability, a high anaerobic toxicity and a high lethal toxicity over Daphnia pulex, for such reasons this leached is cataloged as complex and toxic wastewater. The other hand, wastewater of coffee grain wet treatment plant and wastewater of sanitary landfill they are both highly biodegradability and not-toxic, for such reasons these wastewaters are cataloged as susceptible to treatment by anaerobic biological system

  7. 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.

  8. Assessing impediments to hydrocarbon biodegradation in weathered contaminated soils.

    Science.gov (United States)

    Adetutu, Eric; Weber, John; Aleer, Sam; Dandie, Catherine E; Aburto-Medina, Arturo; Ball, Andrew S; Juhasz, Albert L

    2013-10-15

    In this study, impediments to hydrocarbon biodegradation in contaminated soils were assessed using chemical and molecular methodologies. Two long-term hydrocarbon contaminated soils were utilised which were similar in physico-chemical properties but differed in the extent of hydrocarbon (C10-C40) contamination (S1: 16.5 g kg(-1); S2: 68.9 g kg(-1)). Under enhanced natural attenuation (ENA) conditions, hydrocarbon biodegradation was observed in S1 microcosms (26.4% reduction in C10-C40 hydrocarbons), however, ENA was unable to stimulate degradation in S2. Although eubacterial communities (PCR-DGGE analysis) were similar for both soils, the alkB bacterial community was less diverse in S2 presumably due to impacts associated with elevated hydrocarbons. When hydrocarbon bioaccessibility was assessed using HP-β-CD extraction, large residual concentrations remained in the soil following the extraction procedure. However, when linear regression models were used to predict the endpoints of hydrocarbon degradation, there was no significant difference (P>0.05) between HP-β-CD predicted and microcosm measured biodegradation endpoints. This data suggested that the lack of hydrocarbon degradation in S2 resulted primarily from limited hydrocarbon bioavailability. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. 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

  10. Enhancement of spilled oil biodegradation by nutrients of natural origin

    International Nuclear Information System (INIS)

    Basseres, A.; Eyraud, P.; Ladousse, A.; Tramier, B.

    1993-01-01

    Ten years ago, Elf Aquitaine began developing the technologies for the acceleration of hydrocarbon biodegradation. The continuation of this work has involved the study of new additives to complement the oleophilic nutrient, INIPOL EAP 22. In particular, it has been shown in both laboratory and in situ tests that hydrocarbon degradation can be accelerated by animal meals, which are natural products. Preliminary laboratory studies carried out under batch conditions have shown that the use of these products has resulted in considerable growth of the bacteria, coupled with a notable increase in the biological degradation kinetics of the hydrocarbons. These results are comparable with the performance of the nutrient INIPOL EAP 22. In situ experiments undertaken on soils polluted by hydrocarbons have shown that by using animal meals, 50 percent biodegradation was obtained after six weeks and this increased to 80 percent when mechanical aeration was also employed. Under nutrient-free control conditions, 25 percent biodegradation was obtained with no aeration and 35 percent with mechanical aeration. In trials using coastal sandy sediments, the use of these nutrients has resulted in an increase of both the number of hydrocarbon specific bacteria and the hydrocarbon degradation. It can be concluded from these pilot experiments that in the development of bioremediation as an operational tool in the response to accidental oil spills, these nutrients of natural origin represent an interesting advance

  11. 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)

  12. 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

  13. Durability of Starch Based Biodegradable Plastics Reinforced with Manila Hemp Fibers

    Directory of Open Access Journals (Sweden)

    Shinji Ochi

    2011-02-01

    Full Text Available The biodegradability of Manila hemp fiber reinforced biodegradable plastics was studied for 240 days in a natural soil and 30 days in a compost soil. After biodegradability tests, weights were measured and both tensile strength tests and microscopic observation were performed to evaluate the biodegradation behavior of the composites. The results indicate that the tensile strength of the composites displays a sharp decrease for up to five days, followed by a gradual decrease. The weight loss and the reduction in tensile strength of biodegradable composite materials in the compost soil are both significantly greater than those buried in natural soil. The biodegradability of these composites is enhanced along the lower portion because this area is more easily attacked by microorganisms.

  14. Durability of Starch Based Biodegradable Plastics Reinforced with Manila Hemp Fibers.

    Science.gov (United States)

    Ochi, Shinji

    2011-02-25

    The biodegradability of Manila hemp fiber reinforced biodegradable plastics was studied for 240 days in a natural soil and 30 days in a compost soil. After biodegradability tests, weights were measured and both tensile strength tests and microscopic observation were performed to evaluate the biodegradation behavior of the composites. The results indicate that the tensile strength of the composites displays a sharp decrease for up to five days, followed by a gradual decrease. The weight loss and the reduction in tensile strength of biodegradable composite materials in the compost soil are both significantly greater than those buried in natural soil. The biodegradability of these composites is enhanced along the lower portion because this area is more easily attacked by microorganisms.

  15. 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)

  16. Experimental determination and thermodynamic modeling of phase equilibrium and protein partitioning in aqueous two-phase systems containing biodegradable salts

    International Nuclear Information System (INIS)

    Perez, Brenda; Malpiedi, Luciana Pellegrini; Tubío, Gisela; Nerli, Bibiana; Alcântara Pessôa Filho, Pedro de

    2013-01-01

    Highlights: ► Binodal data of systems (water + polyethyleneglycol + sodium) succinate are reported. ► Pitzer model describes the phase equilibrium of systems formed by polyethyleneglycol and biodegradable salts satisfactorily. ► This simple thermodynamic framework was able to predict the partitioning behaviour of model proteins acceptably well. - Abstract: Phase diagrams of sustainable aqueous two-phase systems (ATPSs) formed by polyethyleneglycols (PEGs) of different average molar masses (4000, 6000, and 8000) and sodium succinate are reported in this work. Partition coefficients (Kps) of seven model proteins: bovine serum albumin, catalase, beta-lactoglobulin, alpha-amylase, lysozyme, pepsin, urease and trypsin were experimentally determined in these systems and in ATPSs formed by the former PEGs and other biodegradable sodium salts: citrate and tartrate. An extension of Pitzer model comprising long and short-range term contributions to the excess Gibbs free energy was used to describe the (liquid + liquid) equilibrium. Comparison between experimental and calculated tie line data showed mean deviations always lower than 3%, thus indicating a good correlation. The partition coefficients were modeled by using the same thermodynamic approach. Predicted and experimental partition coefficients correlated quite successfully. Mean deviations were found to be lower than the experimental uncertainty for most of the assayed proteins.

  17. STUDIES CONCERNING THE INFLUENCE OF BIODEGRADABLE SLOW-RELEASE FERTILIZER USE IN DEVELOPING THE CULTURE OF PETUNIA HYBRIDA SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Mona Popa

    2012-12-01

    Full Text Available Our research on the use of slow-release biodegradable fertilizers were applied to Petunia hybrida seedlings of the variety “White Surfinia”. Thus after 10 days subculturing procedure was to apply fertilizers containing NKP24 biodegradable and made in the form of sticks and granules with six concentrations of starch (5%, 10%, 15%, 20%, 25% and 50% quantaties (4-5 grams/ 1 pot. For each pot with of 8 cm diameter, we prepared a mixture of peat and garden soil in a rate of 1:1. During the vegetation periods, morphological analyses were made regarding the development of Petunia hybrida, cv. “White Surfinia”plants: the length of shoots and number of shoot. Average values recorded from morphological determinations after 1 month of starting experiments on biofertilizers influence on growth and development the seedlings of Petunia was demonstrated that the optimal variant was the fertilizer V5 with -25% WF (wood flour to 50% concentration of biofertilizers NKP24 (for both form of sticks A-big and B-medium and for fertilizer form C- granular the V6 variant with -50% concentration of biofertilizers NKP24, the petunia stem was recorded maximum of 58.92 cm length .The research is part of an international project FP7/2008 with the title "Forest Resource Sustainability through Bio-Based-Composite Development" – FORBIOPLAST. Multiple aims of FORBIOPLAST project are the valorization of forest resources for the production of bio-based products.

  18. Identification of market bags composition for biodegradable and oxo-biodegradable samples through thermal analysis in inert and oxidizer atmosphere

    International Nuclear Information System (INIS)

    Finzi-Quintao, Cristiane M.; Novack, Katia M.

    2015-01-01

    Plastic films used to make market bags are based on polymers such as polyethylene, polystyrene and polypropylene, these materials require a long time to degrade in the environment. The alternative technologies of polymers have been developed to reduce the degradation time and the impact on the environment caused by the conventional materials, using pro-degrading additives or by the development biodegradable polymers. In Brazil, the laws of some municipalities require the use of biodegradable material in the production of market bags but the absence of specific surveillance policies makes its chemical composition unknown. In this paper, we analyzed 7 samples that was obtained from a a trading company and commercial market of Belo Horizonte . The samples were characterized by TGA / DTA , XRF , FTIR and MEV which allowed the identification and evaluation of the thermal behavior of the material in inert and oxidizing atmosphere. (author)

  19. To evaluate the efficacy of biodegradable plating system for fixation of maxillofacial fractures: A prospective study

    OpenAIRE

    Bali, Rishi K.; Sharma, Parveen; Jindal, Shalu; Gaba, Shivani

    2013-01-01

    Aims: The present study was undertaken to evaluate the efficacy of biodegradable plating system for fixation of maxillofacial fractures and to study the morbidity associated with the use of biodegradable plates and screws. Materials and Methods: This prospective study consisted of 10 patients with maxillofacial fractures requiring open reduction and internal fixation. Fractures with infection, comminuted and pathological fractures were excluded. All were plated with biodegradable system (Inio...

  20. Abiotic and Biotic Degradation of Oxo-Biodegradable Plastic Bags by Pleurotus ostreatus

    OpenAIRE

    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 su...