Bioremediation of MGP soils with mixed fungal and bacterial cultures

International Nuclear Information System (INIS)

Lee, C.J.B.; Fletcher, M.A.; Avila, O.I.; Munnecke, D.M.; Callanan, J.; Yunker, S.

1995-01-01

This culture selection study examines the degradation of polycyclic automatic hydrocarbon (PAH) by a number of brown- and white-rot fungi and bacterial cultures for the treatment of coal tar wastes. Cultures were screened for naphthalene degradation in shake flasks, and selected organisms were then examined for their ability to degrade a mixture of PAHs in aqueous culture. PAH degradation in the presence of the surfactant, TWEEN 80, was examined for some cultures. Many of the organisms were observed to be resistant to greater than 10 mg/L free cyanide. Solid substrate growth conditions were optimized for the selected fungal cultures in preparation for manufactured gas plant (MGP) soil microcosm experiments. The fungi generally produced more biomass under conditions of acidic to neutral pH, incubation at 30 C with 90% moisture saturation, and with granulated corncobs or alfalfa pellets supplied as a lignocellulosic substrate. Of the cultures screened, nine fungal cultures were selected based on their ability to degrade at least 40% of naphthalene, fluorene, or benzo(a)pyrene in 2 weeks or less. A bacterial culture capable of degrading 30 mg/L of naphthalene in 1 week was also selected, and the cultures were examined further in PAH-degradation studies in contaminated soils

Fluorene transformation by bacteria of the genus Rhodococcus

NARCIS (Netherlands)

Finkelstein, Z.I.; Baskunov, B.P.; Golovlev, E.L.; Vervoort, J.J.M.; Rietjens, I.M.C.M.; Baboshin, M.A.; Golovleva, L.A.

2003-01-01

Of the four investigated Rhodococcus strains (R. rhodochrous172, R. opacus 4a and 557, and R. rhodnii 135), the first three strains were found to be able to completely transform fluorene when it was present in the medium as the sole source of carbon at a concentration of 12¿25 mg/l. At a fluorene

Supramolecular fluorene based materials

NARCIS (Netherlands)

Abbel, R.J.

2008-01-01

This thesis describes the use of noncovalent interactions in order to manipulate and control the self-assembly and morphology of electroactive fluorene-based materials. The supramolecular arrangement of p-conjugated polymers and oligomers can strongly influence their electronic and photophysical

Soil bacterial diversity in degraded and restored lands of Northeast Brazil.

Science.gov (United States)

Araújo, Ademir Sérgio Ferreira; Borges, Clovis Daniel; Tsai, Siu Mui; Cesarz, Simone; Eisenhauer, Nico

2014-11-01

Land degradation deteriorates biological productivity and affects environmental, social, and economic sustainability, particularly so in the semi-arid region of Northeast Brazil. Although some studies exist reporting gross measures of soil microbial parameters and processes, limited information is available on how land degradation and restoration strategies influence the diversity and composition of soil microbial communities. In this study we compare the structure and diversity of bacterial communities in degraded and restored lands in Northeast Brazil and determine the soil biological and chemical properties influencing bacterial communities. We found that land degradation decreased the diversity of soil bacteria as indicated by both reduced operational taxonomic unit (OTU) richness and Shannon index. Soils under native vegetation and restoration had significantly higher bacterial richness and diversity than degraded soils. Redundancy analysis revealed that low soil bacterial diversity correlated with a high respiratory quotient, indicating stressed microbial communities. By contrast, soil bacterial communities in restored land positively correlated with high soil P levels. Importantly, however, we found significant differences in the soil bacterial community composition under native vegetation and in restored land, which may indicate differences in their functioning despite equal levels of bacterial diversity.

In Situ Hydrocarbon Degradation by Indigenous Nearshore Bacterial Populations

International Nuclear Information System (INIS)

Cherrier, J.

2005-01-01

Potential episodic hydrocarbon inputs associated with oil mining and transportation together with chronic introduction of hydrocarbons via urban runoff into the relatively pristine coastal Florida waters poses a significant threat to Florida's fragile marine environment. It is therefore important to understand the extent to which indigenous bacterial populations are able to degrade hydrocarbon compounds and also determine factors that could potentially control and promote the rate at which these compounds are broken down in situ. Previous controlled laboratory experiments carried out by our research group demonstrated that separately both photo-oxidation and cometabolism stimulate bacterial hydrocarbon degradation by natural bacterial assemblages collected from a chronically petroleum contaminated site in Bayboro Bay, Florida. Additionally, we also demonstrated that stable carbon and radiocarbon abundances of respired CO 2 could be used to trace in situ hydrocarbon degradation by indigenous bacterial populations at this same site. This current proposal had two main objectives: (a) to evaluate the cumulative impact of cometabolism and photo-oxidation on hydrocarbon degradation by natural bacterial assemblages collected the same site in Bayboro Bay, Florida and (b) to determine if in situ hydrocarbon degradation by indigenous bacterial populations this site could be traced using natural radiocarbon and stable carbon abundances of assimilated bacterial carbon. Funds were used for 2 years of full support for one ESI Ph.D. student, April Croxton. To address our first objective a series of closed system bacterial incubations were carried out using photo-oxidized petroleum and pinfish (i.e. cometabolite). Bacterial production of CO 2 was used as the indicator of hydrocarbon degradation and (delta) 13 C analysis of the resultant CO 2 was used to evaluate the source of the respired CO 2 (i.e. petroleum hydrocarbons or the pinfish cometabolite). Results from these time

Isolation and characterization of a novel polychlorinated biphenyl-degrading bacterium, Paenibacillus sp. KBC101

Energy Technology Data Exchange (ETDEWEB)

Sakai, M.; Ezaki, S.; Suzuki, N.; Kurane, R. [Kubota Corporation, Ryuugasaki City (Japan). Biotechnology Research Centre

2005-07-01

The biphenyl-utilizing bacterial strain KBC101 has been newly isolated from soil. Biphenyl-grown cells of KBC101 efficiently degraded di- to nonachlorobiphenyls. The isolate was identified as Paenibacillus sp. with respect to its 16S rDNA sequence and fatty acid profiles, as well as various biological and physiological characteristics. In the case of highly chlorinated biphenyl (polychlorinated biphenyl; PCB) congeners, the degradation activities of this strain were superior to those of the previously reported strong PCB degrader, Rhodococcus sp. RHA1. Recalcitrant coplanar PCBs, such as 3,4,3',4'-CB, were also efficiently degraded by strain KBC101 cells. This is the first report of a representative of the genus Paenibacillus capable of degrading PCBs. In addition to growth of biphenyl, strain KBC101 could grow on dibenzofuran, xanthene, benzophenone, anthrone, phenanthrene, napthalene, fluorene, fluoranthene, and chrysene as sole sources of carbon and energy. Paenibacillus sp. strain KBC101 presented heterogeneous degradation profiles toward various aromatic compounds. (orig.)

The physiological effect of fluorene on Triticum aestivum, Medicago sativa, and Helianthus annus

Directory of Open Access Journals (Sweden)

Seyed Yahya Salehi-Lisar

2015-12-01

Full Text Available Polycyclic aromatic hydrocarbons (PAHs are widespread pollutants and can negatively affect plants. Fluorene is a prevalent PAH in the contaminated environment. In this study, the effects of higher concentrations of fluorene in soil on rate of seed germination, growth, and the physiological parameters of wheat, sunflower, and alfalfa were studied. The results showed that the higher concentration of fluorene decreased rate of seed germination and seedlings growth of plants. Wheat showed the highest resistance at seed germination and seedlings growth phases, and sunflower was the most sensitive species at both stages. Therefore, it was concluded that higher resistance at seed germination could be followed by the higher resistance of seedlings. Fluorene toxicity also induced oxidative stress in plants as shown by MDA accumulation in the plants. There was a significant correlation between the lower activity of CAT and MDA accumulation in the studied plants. Therefore, CAT could be an important enzyme involved in detoxification of ROS and plants resistance to fluorene toxicity. Depending on plant species and fluorene concentration, photosynthetic pigments content was differently affected.

Optically enhanced nuclear cross polarization in acridine-doped fluorene

Energy Technology Data Exchange (ETDEWEB)

Oshiro, C.M.

1982-06-01

The objective of this work has been to create large polarizations of the dilute /sup 13/C nuclei in the solid state. The idea was to create /sup 1/H polarizations larger than Boltzmann and to use the proton enhanced nuclear induction spectroscopy cross polarization technique to then transfer this large polarization to the /sup 13/C spin system. Optical Nuclear Polarization (ONP) of acridine-doped fluorene single crystals was studied. In addition, ONP of powdered samples of the acridine-doped fluorene was studied. In general, many compounds do not crystallize easily or do not form large crystals suitable for NMR experiments. Powdered, amorphous and randomly dispersed samples are generally far more readily available than single crystals. One objective of this work has been to (first) create large /sup 1/H polarizations. Although large optical proton polarizations in single crystals have been reported previously, optically generated polarizations in powdered samples have not been reported. For these reasons, ONP studies of powdered samples of the acridine-doped fluorene were also undertaken. Using ONP in combination with the proton enhanced nuclear induction spectroscopy experiment, large /sup 13/C polarizations have been created in fluorene single crystals. These large /sup 13/C polarizations have permitted the determination of the seven incongruent chemical shielding tensors of the fluorene molecule. Part 2 of this thesis describes the proton enhanced nuclear induction spectroscopy experiment. Part 3 describes the ONP experiment. Part 4 is a description of the experimental set-up. Part 5 describes the data analysis for the determination of the chemical shielding tensors. Part 6 presents the results of the ONP experiments performed in this work and the chemical shielding tensors determined.

Optically enhanced nuclear cross polarization in acridine-doped fluorene

International Nuclear Information System (INIS)

Oshiro, C.M.

1982-06-01

The objective of this work has been to create large polarizations of the dilute 13 C nuclei in the solid state. The idea was to create 1 H polarizations larger than Boltzmann and to use the proton enhanced nuclear induction spectroscopy cross polarization technique to then transfer this large polarization to the 13 C spin system. Optical Nuclear Polarization (ONP) of acridine-doped fluorene single crystals was studied. In addition, ONP of powdered samples of the acridine-doped fluorene was studied. In general, many compounds do not crystallize easily or do not form large crystals suitable for NMR experiments. Powdered, amorphous and randomly dispersed samples are generally far more readily available than single crystals. One objective of this work has been to (first) create large 1 H polarizations. Although large optical proton polarizations in single crystals have been reported previously, optically generated polarizations in powdered samples have not been reported. For these reasons, ONP studies of powdered samples of the acridine-doped fluorene were also undertaken. Using ONP in combination with the proton enhanced nuclear induction spectroscopy experiment, large 13 C polarizations have been created in fluorene single crystals. These large 13 C polarizations have permitted the determination of the seven incongruent chemical shielding tensors of the fluorene molecule. Part 2 of this thesis describes the proton enhanced nuclear induction spectroscopy experiment. Part 3 describes the ONP experiment. Part 4 is a description of the experimental set-up. Part 5 describes the data analysis for the determination of the chemical shielding tensors. Part 6 presents the results of the ONP experiments performed in this work and the chemical shielding tensors determined

Fungal hyphae stimulate bacterial degradation of 2,6-dichlorobenzamide (BAM)

International Nuclear Information System (INIS)

Knudsen, Berith Elkær; Ellegaard-Jensen, Lea; Albers, Christian Nyrop; Rosendahl, Søren; Aamand, Jens

2013-01-01

Introduction of specific degrading microorganisms into polluted soil or aquifers is a promising remediation technology provided that the organisms survive and spread in the environment. We suggest that consortia, rather than single strains, may be better suited to overcome these challenges. Here we introduced a fungal–bacterial consortium consisting of Mortierella sp. LEJ702 and the 2,6-dichlorobenzamide (BAM)-degrading Aminobacter sp. MSH1 into small sand columns. A more rapid mineralisation of BAM was obtained by the consortium compared to MSH1 alone especially at lower moisture contents. Results from quantitative real-time polymerase chain reaction (qPCR) demonstrated better spreading of Aminobacter when Mortierella was present suggesting that fungal hyphae may stimulate bacterial dispersal. Extraction and analysis of BAM indicated that translocation of the compound was also affected by the fungal hyphae in the sand. This suggests that fungal–bacterial consortia are promising for successful bioremediation of pesticide contamination. -- Highlights: •Presence of fungi increased the rate of BAM mineralization by Aminobacter sp. MSH1. •Fungal–bacterial consortium enhanced BAM degradation at low moisture contents. •Mortierella hyphae facilitated transport of the BAM degrader Aminobacter sp. MSH1. -- This study brings new knowledge to the benefits of applying bacterial–fungal consortia for bioremediation

Microbial activity and bacterial community structure during degradation of microcystins

DEFF Research Database (Denmark)

Christoffersen, K.; Lyck, Susanne; Winding, A.

2002-01-01

experiments were analysed by polymerase chain reaction-density gradient gel electrophoresis (PCR-DGGE) of 16S rDNA, which showed that the indigenous bacterial community responded quickly to the addition of lysates. Our study confirms that bacteria can efficiently degrade microcystins in natural waters....... It was hypothesised that the bacterial community from a lake with frequent occurrence of toxic cyanobacteria can degrade microcystin along with other organic compounds. The initial dissolved microcystin concentrations ranged between 10 and 136 mug 1(-1) (microcystin-LR equivalents) in the laboratory experiment, using...... experiment to evaluate the effects of organic lysates on bacterial proliferation in the absence of microcystin. An exponential decline of the dissolved toxins was observed in all cases with toxins present, and the degradation rates ranged between 0.5 and 1.0 d(-1). No lag phases were observed but slow...

Supramolecular fluorene based materials

OpenAIRE

Abbel, R.J.

2008-01-01

This thesis describes the use of noncovalent interactions in order to manipulate and control the self-assembly and morphology of electroactive fluorene-based materials. The supramolecular arrangement of p-conjugated polymers and oligomers can strongly influence their electronic and photophysical properties. Therefore, a detailed understanding of such organisation processes is essential for the optimisation of the performance of these materials as applied in optoelectronic devices. In order to...

Thermal high pressure hydrogenolysis II. The thermal high pressure hydrocracking of fluorene

NARCIS (Netherlands)

Oltay, Ernst; Penninger, Johannes M.L.; Konter, Willem A.N.

1973-01-01

The thermal hydrocracking of fluorene was investigated in the temperature range of 400 to 480 °C and hydrogen pressures of up to 375 atm. As main reaction products were found 2-methylbiphenyl, biphenyl, toluene and benzene. They account for about 90% of the converted fluorene. Only very low

White organic light emitting diodes based on fluorene-carbazole dendrimers

International Nuclear Information System (INIS)

Usluer, Özlem; Demic, Serafettin; Kus, Mahmut; Özel, Faruk; Serdar Sariciftci, Niyazi

2014-01-01

In this paper, we report on theProd. Type: FTP fabrication and characterization of blue and white light emitting devices based on two fluorene-carbazole containing dendrimers and para-sexiphenyl (6P) oligomers. Blue light emitting diodes were fabricated using 9′,9″-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis-9′H-9,3′:6′,9″-tercarbazole (OFC-G2) and 9′,9″-(9,9′-spirobi[fluorene]-2,7-diyl)bis-9′H-9,3′:6′,9″-tercarbazole (SBFC-G2) dendrimers as a hole transport and emissive layer (EML) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) as an electron transport layer. White light emitting diodes were fabricated using 6P and these two dendrimers as an EML. OLED device with the structure of ITO/PEDOT:PSS (50 nm)/OFC-G2 (40 nm)/6P (20 nm)/LiF:Al (0.5:100 nm) shows maximum luminance of nearly 1400 cd/m 2 and a Commission Internationale de l'Eclairage chromaticity coordinates of (0.27, 0.30) at 12 V. -- Highlights: • White organic light emitting diodes have been fabricated using two fluorene-carbazole dendrimers and para-sexiphenyl (6P) oligomers. • When only these two dendrimers are used as EML, OLED devices are emitted blue light. • The emission colors of OLED devices change from blue to white when 6P is coated on dendrimer films

Isolation of amoebic-bacterial consortia capable of degrading trichloroethylene

International Nuclear Information System (INIS)

Tyndall, R.L.; Ironside, K.; Little, C.D.; Katz, S.; Kennedy, J.

1990-01-01

Groundwater from a waste disposal site contaminated with chlorinated alkenes was examined for the presence of amoebic-bacterial consortia capable of degrading the suspected carcinogen, trichloroethylene (TCE). Consortia were readily isolated from all of four test wells. They contained free-living amoebae, and heterotrophic and methylotrophic bacteria. Electron microscopic examination showed bacteria localized throughout the amoebic cytoplasm and an abundance of hyphomicrobium, but not Type I methanotrophs. The presence of Type II methanotrophs was indirectly indicated by lipid analysis of one consortium. The consortia have been passaged for over two years on mineral salts media in a methane atmosphere, which would not be expected to maintain the heterotrophs or amoebae separately. The methanotrophic bacteria apparently provided a stable nutrient source, allowing the persistence of the various genera. By use of 14 C-radiotracer techniques, the degradation of TCE by the consortia was observed with 14 C eventuating predominantly in CO 2 and water-soluble products. In a more detailed examination of one consortia, the amoebae and heterotrohic components did not degrade TCE, while a mixed culture of heterotrophs and methanotrophs did degrade TCE, suggesting the latter component was the primary cause for the consortium's ability to degrade TCE. Amoebic-bacterial consortia may play a role in stabilizing and preserving methylotrophic bacteria in hostile environments

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 ...

White organic light emitting diodes based on fluorene-carbazole dendrimers

Energy Technology Data Exchange (ETDEWEB)

Usluer, Özlem, E-mail: usluerozlem@yahoo.com.tr [Department of Chemistry, Muğla Sıtkı Koçman University, 48000 Muğla (Turkey); Demic, Serafettin [Department of Materials Science and Engineering, Izmir Katip Çelebi University, 35620 Çiğli, Izmir (Turkey); Kus, Mahmut, E-mail: mahmutkus1@gmail.com [Chemical Engineering Department and Advanced Technology R and D Center, Selçuk University, Konya (Turkey); Özel, Faruk [Chemical Engineering Department and Advanced Technology R and D Center, Selçuk University, Konya (Turkey); Serdar Sariciftci, Niyazi [Linz Institute for Organic Solar Cells (LIOS), Physical Chemistry, Johannes Kepler University, Altenbergerstr. 69, A-4040 Linz (Austria)

2014-02-15

In this paper, we report on theProd. Type: FTP fabrication and characterization of blue and white light emitting devices based on two fluorene-carbazole containing dendrimers and para-sexiphenyl (6P) oligomers. Blue light emitting diodes were fabricated using 9′,9″-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis-9′H-9,3′:6′,9″-tercarbazole (OFC-G2) and 9′,9″-(9,9′-spirobi[fluorene]-2,7-diyl)bis-9′H-9,3′:6′,9″-tercarbazole (SBFC-G2) dendrimers as a hole transport and emissive layer (EML) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) as an electron transport layer. White light emitting diodes were fabricated using 6P and these two dendrimers as an EML. OLED device with the structure of ITO/PEDOT:PSS (50 nm)/OFC-G2 (40 nm)/6P (20 nm)/LiF:Al (0.5:100 nm) shows maximum luminance of nearly 1400 cd/m{sup 2} and a Commission Internationale de l'Eclairage chromaticity coordinates of (0.27, 0.30) at 12 V. -- Highlights: • White organic light emitting diodes have been fabricated using two fluorene-carbazole dendrimers and para-sexiphenyl (6P) oligomers. • When only these two dendrimers are used as EML, OLED devices are emitted blue light. • The emission colors of OLED devices change from blue to white when 6P is coated on dendrimer films.

Biofuel components change the ecology of bacterial volatile petroleum hydrocarbon degradation in aerobic sandy soil

International Nuclear Information System (INIS)

Elazhari-Ali, Abdulmagid; Singh, Arvind K.; Davenport, Russell J.; Head, Ian M.; Werner, David

2013-01-01

We tested the hypothesis that the biodegradation of volatile petroleum hydrocarbons (VPHs) in aerobic sandy soil is affected by the blending with 10 percent ethanol (E10) or 20 percent biodiesel (B20). When inorganic nutrients were scarce, competition between biofuel and VPH degraders temporarily slowed monoaromatic hydrocarbon degradation. Ethanol had a bigger impact than biodiesel, reflecting the relative ease of ethanol compared to methyl ester biodegradation. Denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA genes revealed that each fuel mixture selected for a distinct bacterial community, each dominated by Pseudomonas spp. Despite lasting impacts on soil bacterial ecology, the overall effects on VHP biodegradation were minor, and average biomass yields were comparable between fuel types, ranging from 0.40 ± 0.16 to 0.51 ± 0.22 g of biomass carbon per gram of fuel carbon degraded. Inorganic nutrient availability had a greater impact on petroleum hydrocarbon biodegradation than fuel composition. Highlights: ► The effect of 10% ethanol or 20% biodiesel on the biodegradability of volatile petroleum hydrocarbons in soil was investigated. ► Competition for scarce inorganic nutrients between biofuel and VPH degraders slowed monoaromatic hydrocarbon degradation. ► Biofuel effects were transitional. ► Each fuel selected for a distinct predominant bacterial community. ► All bacterial communities were dominated by Pseudomonas spp. - Blending of petroleum with ethanol or biodiesel changes the fuel degrading soil bacterial community structure, but the long-term effects on fuel biodegradability are minor.

Electronic transitions of fluorene, dibenzofuran, carbazole, and dibenzothiophene

DEFF Research Database (Denmark)

Nguyen, Duy Duc; Trunk, John; Nakhimovsky, Lina

2010-01-01

A comparative study of the electronic transitions of fluorene and its hetero-analogues dibenzofuran, carbazole, and dibenzothiophene was performed in a wide energy range. Gas phase, crystal phase, and linear dichroism electronic transmittance spectra were measured with synchrotron radiation...

Fungal hyphae stimulate bacterial degradation of 2,6-dichlorobenzamide (BAM).

Science.gov (United States)

Knudsen, Berith Elkær; Ellegaard-Jensen, Lea; Albers, Christian Nyrop; Rosendahl, Søren; Aamand, Jens

2013-10-01

Introduction of specific degrading microorganisms into polluted soil or aquifers is a promising remediation technology provided that the organisms survive and spread in the environment. We suggest that consortia, rather than single strains, may be better suited to overcome these challenges. Here we introduced a fungal-bacterial consortium consisting of Mortierella sp. LEJ702 and the 2,6-dichlorobenzamide (BAM)-degrading Aminobacter sp. MSH1 into small sand columns. A more rapid mineralisation of BAM was obtained by the consortium compared to MSH1 alone especially at lower moisture contents. Results from quantitative real-time polymerase chain reaction (qPCR) demonstrated better spreading of Aminobacter when Mortierella was present suggesting that fungal hyphae may stimulate bacterial dispersal. Extraction and analysis of BAM indicated that translocation of the compound was also affected by the fungal hyphae in the sand. This suggests that fungal-bacterial consortia are promising for successful bioremediation of pesticide contamination. Copyright © 2013 Elsevier Ltd. All rights reserved.

The effects of temperature and pH bacterial degradation of latex ...

African Journals Online (AJOL)

The goal of this study was to integrate the activities of paint deterioration of microbial communities (microcosms) on the basis of environmental factors. The effect of temperature and pH on bacterial degradation of latex paint under humid condition by bacterial isolates was studied. Results obtained revealed that paint ...

Fluorene and Phenanthrene Uptake and Accumulation by Wheat, Alfalfa and Sunflower from the Contaminated Soil.

Science.gov (United States)

Salehi-Lisar, Seyed Yahya; Deljoo, Somaye; Harzandi, Ahmad Mosen

2015-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) are diverse organic contaminants released into the environment by both natural and anthropogenic activities. These compounds have negative impacts on plants growth and development. Although there are many reports on their existence in different parts of plant, their uptake and translocation pathways and mechanisms are not well understood yet. This paper highlights the uptake, translocation and accumulation of PAHs by wheat, sunflower and alfalfa through an experimental study under controlled conditions. Seeds were cultivated in a soil containing 50 mg/kg of phenanthrene and fluorene and their concentrations in plants roots and shoots were determined using a gas chromatograph after 7 and 14 days. The results showed that phenanthrene and fluorene concentrations in the treated plants were increased over the time. PAHs bioavailability was time and species dependent and generally, phenanthrene uptake and translocation was faster than that of fluorene, probably due to their higher Kow. Fluorene tended to accumulate in roots, but phenanthrene was transported to aerial parts of plants.

Isolation and characterization of bacteria capable of degrading polycyclic aromatic hydrocarbons (PAHs) and organophosphorus pesticides from PAH-contaminated soil in Hilo, Hawaii.

Science.gov (United States)

Seo, Jong-Su; Keum, Young-Soo; Harada, Renee M; Li, Qing X

2007-07-11

Nineteen bacterial strains were isolated from petroleum-contaminated soil in Hilo, HI, and characterized by two different spray-plated methods, turbidity test in liquid medium, and 16S rRNA gene sequence analysis. Analysis of the soil showed 13 polycyclic aromatic hydrocarbons (PAHs) in a range from 0.6 to 30 mg/kg of dry weight each and 12 PAH metabolites. Five distinct bacterial strains (C3, C4, P1-1, JS14, and JS19b1) selected from preliminary plating and turbidity tests were further tested for PAH degradation through single PAH degradation assay. Strains C3, C4, and P1-1 degraded phenanthrene (40 mg/L) completely during 7 days of incubation. Strain JS14 degraded fluoranthene (40 mg/L) completely during 10 days of incubation. Strain JS19b1 degraded 100% of phenanthrene (40 mg/L) in 7 days, 77% of fluorene (40 mg/L) in 14 days, 97% of fluoranthene (40 mg/L) in 10 days, and 100% of pyrene (40 mg/L) in 14 days. Turbidity tests showed that strains P1-1, JS14, and JS19b1 utilized several organophosphorus pesticides as growth substrate. P1-1 can degrade carbofenothion, chlorfenvinphos, diazinon, fonofos, and pirimiphos-methyl. JS14 can transform chlorfenvinphos and diazinon. JS19b1 can break down diazinon, pirimiphos-methyl, and temephos.

Regional analysis of potential polychlorinated biphenyl degrading bacterial strains from China

Directory of Open Access Journals (Sweden)

Jianjun Shuai

Full Text Available ABSTRACT Polychlorinated biphenyls (PCBs, the chlorinated derivatives of biphenyl, are one of the most prevalent, highly toxic and persistent groups of contaminants in the environment. The objective of this study was to investigate the biodegradation of PCBs in northeastern (Heilongjiang Province, northern (Shanxi Province and eastern China (Shanghai municipality. From these areas, nine soil samples were screened for PCB-degrading bacteria using a functional complementarity method. The genomic 16S rDNA locus was amplified and the products were sequenced to identify the bacterial genera. Seven Pseudomonas strains were selected to compare the capacity of bacteria from different regions to degrade biphenyl by HPLC. Compared to the biphenyl content in controls of 100%, the biphenyl content went down to 3.7% for strain P9-324, 36.3% for P2-11, and 20.0% for the other five strains. These results indicate that a longer processing time led to more degradation of biphenyl. PCB-degrading bacterial strains are distributed differently in different regions of China.

Characterization and degradation potential of diesel-degrading bacterial strains for application in bioremediation.

Science.gov (United States)

Balseiro-Romero, María; Gkorezis, Panagiotis; Kidd, Petra S; Van Hamme, Jonathan; Weyens, Nele; Monterroso, Carmen; Vangronsveld, Jaco

2017-10-03

Bioremediation of polluted soils is a promising technique with low environmental impact, which uses soil organisms to degrade soil contaminants. In this study, 19 bacterial strains isolated from a diesel-contaminated soil were screened for their diesel-degrading potential, biosurfactant (BS) production, and biofilm formation abilities, all desirable characteristics when selecting strains for re-inoculation into hydrocarbon-contaminated soils. Diesel-degradation rates were determined in vitro in minimal medium with diesel as the sole carbon source. The capacity to degrade diesel range organics (DROs) of strains SPG23 (Arthobacter sp.) and PF1 (Acinetobacter oleivorans) reached 17-26% of total DROs after 10 days, and 90% for strain GK2 (Acinetobacter calcoaceticus). The amount and rate of alkane degradation decreased significantly with increasing carbon number for strains SPG23 and PF1. Strain GK2, which produced BSs and biofilms, exhibited a greater extent, and faster rate of alkane degradation compared to SPG23 and PF1. Based on the outcomes of degradation experiments, in addition to BS production, biofilm formation capacities, and previous genome characterizations, strain GK2 is a promising candidate for microbial-assisted phytoremediation of diesel-contaminated soils. These results are of particular interest to select suitable strains for bioremediation, not only presenting high diesel-degradation rates, but also other characteristics which could improve rhizosphere colonization.

Modification and Assembly of a Versatile Lactonase for Bacterial Quorum Quenching

Directory of Open Access Journals (Sweden)

Melissa K. Rhoads

2018-02-01

Full Text Available This work sets out to provide a self-assembled biopolymer capsule activated with a multi-functional enzyme for localized delivery. This enzyme, SsoPox, which is a lactonase and phosphotriesterase, provides a means of interrupting bacterial communication pathways that have been shown to mediate pathogenicity. Here we demonstrate the capability to express, purify and attach SsoPox to the natural biopolymer chitosan, preserving its activity to “neutralize” long-chain autoinducer-1 (AI-1 communication molecules. Attachment is shown via non-specific binding and by engineering tyrosine and glutamine affinity ‘tags’ at the C-terminus for covalent linkage. Subsequent degradation of AI-1, in this case N-(3-oxododecanoyl-l-homoserine lactone (OdDHL, serves to “quench” bacterial quorum sensing (QS, silencing intraspecies communication. By attaching enzymes to pH-responsive chitosan that, in turn, can be assembled into various forms, we demonstrate device-based flexibility for enzyme delivery. Specifically, we have assembled quorum-quenching capsules consisting of an alginate inner core and an enzyme “decorated” chitosan shell that are shown to preclude bacterial QS crosstalk, minimizing QS mediated behaviors.

Exploring bacterial lignin degradation.

Science.gov (United States)

Brown, Margaret E; Chang, Michelle C Y

2014-04-01

Plant biomass represents a renewable carbon feedstock that could potentially be used to replace a significant level of petroleum-derived chemicals. One major challenge in its utilization is that the majority of this carbon is trapped in the recalcitrant structural polymers of the plant cell wall. Deconstruction of lignin is a key step in the processing of biomass to useful monomers but remains challenging. Microbial systems can provide molecular information on lignin depolymerization as they have evolved to break lignin down using metalloenzyme-dependent radical pathways. Both fungi and bacteria have been observed to metabolize lignin; however, their differential reactivity with this substrate indicates that they may utilize different chemical strategies for its breakdown. This review will discuss recent advances in studying bacterial lignin degradation as an approach to exploring greater diversity in the environment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bio-degradation of oily food waste employing thermophilic bacterial strains.

Science.gov (United States)

Awasthi, Mukesh Kumar; Selvam, Ammaiyappan; Chan, Man Ting; Wong, Jonathan W C

2018-01-01

The objective of this work was to isolate a novel thermophilic bacterial strain and develop a bacterial consortium (BC) for efficient degradation oily food waste. Four treatments were designed: 1:1 mixture of pre-consumption food wastes (PrCFWs) and post-consumption food wastes (PCFWs) (T-1), 1:2 mixture of PrCFWs and PCFWs mixture (T-2), PrCFWs (T-3) and PCFWs (T-4). Equal quantity of BC was inoculated into each treatment to compare the oil degradation efficiency. Results showed that after 15days of incubation, a maximum oil reduction of 65.12±0.08% was observed in treatment T-4, followed by T-2 (55.44±0.12%), T-3 (54.79±0.04%) and T-1 (52.52±0.02%), while oil reduction was negligible in control. Results indicate that the development of oil utilizing thermophilic BC was more cost-effective in solving the degradation of oily food wastes and conversion into a stable end product. Copyright © 2017 Elsevier Ltd. All rights reserved.

Carbazole degradation in the soil microcosm by tropical bacterial strains

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Lateef B. Salam

2015-01-01

Full Text Available In a previous study, three bacterial strains isolated from tropical hydrocarbon-contaminated soils and phylogenetically identified as Achromobacter sp. strain SL1, Pseudomonassp. strain SL4 and Microbacterium esteraromaticum strain SL6 displayed angular dioxygenation and mineralization of carbazole in batch cultures. In this study, the ability of these isolates to survive and enhance carbazole degradation in soil were tested in field-moist microcosms. Strain SL4 had the highest survival rate (1.8 x 107 cfu/g after 30 days of incubation in sterilized soil, while there was a decrease in population density in native (unsterilized soil when compared with the initial population. Gas chromatographic analysis after 30 days of incubation showed that in sterilized soil amended with carbazole (100 mg/kg, 66.96, 82.15 and 68.54% were degraded by strains SL1, SL4 and SL6, respectively, with rates of degradation of 0.093, 0.114 and 0.095 mg kg−1 h−1. The combination of the three isolates as inoculum in sterilized soil degraded 87.13% carbazole at a rate of 0.121 mg kg−1 h−1. In native soil amended with carbazole (100 mg/kg, 91.64, 87.29 and 89.13% were degraded by strains SL1, SL4 and SL6 after 30 days of incubation, with rates of degradation of 0.127, 0.121 and 0.124 mg kg−1h−1, respectively. This study successfully established the survivability (> 106 cfu/g detected after 30 days and carbazole-degrading ability of these bacterial strains in soil, and highlights the potential of these isolates as seed for the bioremediation of carbazole-impacted environments.

Evaluating robustness of a diesel-degrading bacterial consortium isolated from contaminated soil

DEFF Research Database (Denmark)

Sydow, Mateusz; Owsianiak, Mikolaj; Szczepaniak, Zuzanna

2016-01-01

It is not known whether diesel-degrading bacterial communities are structurally and functionally robust when exposed to different hydrocarbon types. Here, we exposed a diesel-degrading consortium to model either alkanes, cycloalkanes or aromatic hydrocarbons as carbon sources to study its...... structural resistance. The structural resistance was low, with changes in relative abundances of up to four orders of magnitude, depending on hydrocarbon type and bacterial taxon. This low resistance is explained by the presence of hydrocarbon-degrading specialists in the consortium and differences in growth...... kinetics on individual hydrocarbons. However, despite this low resistance, structural and functional resilience were high, as verified by re-exposing the hydrocarbon-perturbed consortium to diesel fuel. The high resilience is either due to the short exposure time, insufficient for permanent changes...

Bacterial community dynamics during polysaccharide degradation at contrasting sites in the Southern and Atlantic Oceans.

Science.gov (United States)

Wietz, Matthias; Wemheuer, Bernd; Simon, Heike; Giebel, Helge-Ansgar; Seibt, Maren A; Daniel, Rolf; Brinkhoff, Thorsten; Simon, Meinhard

2015-10-01

The bacterial degradation of polysaccharides is central to marine carbon cycling, but little is known about the bacterial taxa that degrade specific marine polysaccharides. Here, bacterial growth and community dynamics were studied during the degradation of the polysaccharides chitin, alginate and agarose in microcosm experiments at four contrasting locations in the Southern and Atlantic Oceans. At the Southern polar front, chitin-supplemented microcosms were characterized by higher fractions of actively growing cells and a community shift from Alphaproteobacteria to Gammaproteobacteria and Bacteroidetes. At the Antarctic ice shelf, chitin degradation was associated with growth of Bacteroidetes, with 24% higher cell numbers compared with the control. At the Patagonian continental shelf, alginate and agarose degradation covaried with growth of different Alteromonadaceae populations, each with specific temporal growth patterns. At the Mauritanian upwelling, only the alginate hydrolysis product guluronate was consumed, coincident with increasing abundances of Alteromonadaceae and possibly cross-feeding SAR11. 16S rRNA gene amplicon libraries indicated that growth of the Bacteroidetes-affiliated genus Reichenbachiella was stimulated by chitin at all cold and temperate water stations, suggesting comparable ecological roles over wide geographical scales. Overall, the predominance of location-specific patterns showed that bacterial communities from contrasting oceanic biomes have members with different potentials to hydrolyse polysaccharides. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Optoelectronic properties of a novel fluorene derivative for organic light-emitting diode

Energy Technology Data Exchange (ETDEWEB)

Yu, Junsheng; Lou, Shuangling; Qian, Jincheng; Jiang, Yadong [University of Electronic Science and Technology of China (UESTC), State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, Chengdu (China); Zhang, Qing [Shanghai Jiaotong University, Department of Polymer Science, School of Chemistry and Chemical Technology, Shanghai (China)

2009-03-15

We report the optoelectronic properties of a novel fluorene derivative of 6,6'-(9H-fluoren-9,9-diyl)bis(2,3-bis (9,9-dihexyl-9H-fluoren-2-yl)quinoxaline) (BFLBBFLYQ) used for organic light-emitting diode. UV-Vis absorption, photoluminescence (PL) and electroluminescence (EL) spectra of BFLBBFLYQ and the blend doped with N,N'-biphenyl-N,N'-bis-(3-methylphenyl)-1,1'-biphenyl-4,4'-di- amine (TPD) in solid state and in solution were investigated. The results showed that BFLBBFLYQ had a PL peak at 451 nm in solid and solution states and an EL peak at 483 nm with a broad emission band, resulting from fluorenone defects. Exciplex emission was observed in BFLBBFLYQ-TPD blend solid state with a green emission peaking at 530 nm. Also the blend in solution showed solvatochromism in polarity solvent upon UV irradiation. A new absorption band appeared at around 470 nm of BFLBBFLYQ-TPD blend in chloroform solution, and disappeared when diluted in absorption spectrum. Meanwhile, a low energy emission band from 530 to 580 nm appeared and increased with material concentration and UV irradiation time. (orig.)

Fungal–bacterial consortia increase diuron degradation in water-unsaturated systems

DEFF Research Database (Denmark)

Ellegaard-Jensen, Lea; Knudsen, Berith Elkær; Johansen, Anders

2014-01-01

organism. In addition, fungal hyphae may function as transport vectors for bacteria, thereby facilitating a more effective spreading of degrader organisms in the soil. A more rapid mineralization of the phenylurea herbicide diuron was found in sand with added microbial consortia consisting of both...... degrading bacteria and fungi. Facilitated transport of bacteria by fungal hyphae was demonstrated using a system where herbicide-spiked sand was separated from the consortium by a layer of sterile glass beads. Several fungal–bacterial consortia were investigated by combining different diuron...

Towards a universal microbial inoculum for dissolved organic carbon degradation experiments

Science.gov (United States)

Pastor, Ada; Catalán, Núria; Gutiérrez, Carmen; Nagar, Nupur; Casas-Ruiz, Joan P.; Obrador, Biel; von Schiller, Daniel; Sabater, Sergi; Petrovic, Mira; Borrego, Carles M.; Marcé, Rafael

2017-04-01

Dissolved organic carbon (DOC) is the largest biologically available pool of organic carbon in aquatic ecosystems and its degradation along the land-to-ocean continuum has implications for carbon cycling from local to global scales. DOC biodegradability is usually assessed by incubating filtered water inoculated with native microbial assemblages in the laboratory. However, the use of a native inoculum from several freshwaters, without having a microbial-tailored design, hampers our ability to tease apart the relative contribution of the factors driving DOC degradation from the effects of local microbial communities. The use of a standard microbial inoculum would allow researchers to disentangle the drivers of DOC degradation from the metabolic capabilities of microbial communities operating in situ. With this purpose, we designed a bacterial inoculum to be used in experiments of DOC degradation in freshwater habitats. The inoculum is composed of six bacterial strains that easily grow under laboratory conditions, possess a versatile metabolism and are able to grow under both aerobic and anaerobic conditions. The mixed inoculum showed higher DOC degradation rates than those from their isolated bacterial components and the consumption of organic substrates was consistently replicated. Moreover, DOC degradation rates obtained using the designed inoculum were responsive across a wide range of natural water types differing in DOC concentration and composition. Overall, our results show the potential of the designed inoculum as a tool to discriminate between the effects of environmental drivers and intrinsic properties of DOC on degradation dynamics.

Vectorial photoinduced energy transfer between boron-dipyrromethene (Bodipy) chromophores across a fluorene bridge.

Science.gov (United States)

Puntoriero, Fausto; Nastasi, Francesco; Campagna, Sebastiano; Bura, Thomas; Ziessel, Raymond

2010-08-02

A series of novel multichromophoric, luminescent compounds has been prepared, and their absorption spectra, luminescence properties (both at 77 K in rigid matrix and at 298 K in fluid solution), and photoinduced intercomponent energy-transfer processes have been studied. The series contains two new multichromophoric systems 1 and 2, each one containing two different boron-dipyrromethene (Bodipy) subunits and one bridging fluorene species, and two fluorene-Bodipy bichromophoric species, 6 and 7. Three monochromophoric compounds, 3, 4, and 5, used as precursors in the synthetic process, were also fully characterized. The absorption spectra of the multichromophoric compounds are roughly the summation of the absorption spectra of their individual components, thus demonstrating the supramolecular nature of the assemblies. Luminescence studies show that quantitative energy transfer occurs in 6 and 7 from the fluorene chromophore to the Bodipy dyes. Luminescence studies, complemented by transient-absorption spectroscopy studies, also indicate that efficient inter-Bodipy energy transfer across the rigid fluorene spacer takes place in 1 and 2, with rate constants, evaluated by several experimental methods, between 2.0 and 7.0 x 10(9) s(-1). Such an inter-Bodipy energy transfer appears to be governed by the Förster mechanism. By taking advantage of the presence of various protonable sites in the substituents of the lower-energy Bodipy subunit of 1 and 2, the effect of protonation on the energy-transfer rates has also been investigated. The results suggest that control of energy-transfer rate and efficiency of inter-Bodipy energy transfer in this type of systems can be achieved by an external, reversible input.

Degradation of some representative polycyclic aromatic hydrocarbons by the water-soluble protein extracts from Zea mays L. cv PR32-B10.

Science.gov (United States)

Barone, Roberto; de Biasi, Margherita-Gabriella; Piccialli, Vincenzo; de Napoli, Lorenzo; Oliviero, Giorgia; Borbone, Nicola; Piccialli, Gennaro

2016-10-01

The ability of the water-soluble protein extracts from Zea mais L. cv. PR32-B10 to degrade some representative polycyclic aromatic hydrocarbons (PAHs), has been evaluated. Surface sterilized seeds of corn (Zea mais L. Pioneer cv. PR32-B10) were hydroponically cultivated in a growth chamber under no-stressful conditions. The water-soluble protein extracts isolated from maize tissues showed peroxidase, polyphenol oxidase and catalase activities. Incubation of the extracts with naphthalene, fluorene, phenanthrene and pyrene, led to formation of oxidized and/or degradation products. GC-MS and TLC monitoring of the processes showed that naphthalene, phenanthrene, fluorene and pyrene underwent 100%, 78%, 92% and 65% oxidative degradation, respectively, after 120 min. The chemical structure of the degradation products were determined by (1)H NMR and ESI-MS spectrometry. Copyright © 2016 Elsevier Ltd. All rights reserved.

Delignification and Enhanced Gas Release from Soil Containing Lignocellulose by Treatment with Bacterial Lignin Degraders.

Science.gov (United States)

Rashid, Goran M M; Duran-Pena, Maria Jesus; Rahmanpour, Rahman; Sapsford, Devin; Bugg, Timothy D H

2017-04-10

The aim of the study was to isolate bacterial lignin-degrading bacteria from municipal solid waste soil, and to investigate whether they could be used to delignify lignocellulose-containing soil, and enhance methane release. A set of 20 bacterial lignin degraders, including 11 new isolates from municipal solid waste soil, were tested for delignification and phenol release in soil containing 1% pine lignocellulose. A group of 7 strains were then tested for enhancement of gas release from soil containing 1% lignocellulose in small-scale column tests. Using an aerobic pre-treatment, aerobic strains such as Pseudomonas putida showed enhanced gas release from the treated sample, but four bacterial isolates showed 5-10 fold enhancement in gas release in an in situ experiment under microanaerobic conditions: Agrobacterium sp., Lysinibacillus sphaericus, Comamonas testosteroni, and Enterobacter sp.. The results show that facultative anaerobic bacterial lignin degraders found in landfill soil can be used for in situ delignification and enhanced gas release in soil containing lignocellulose. The study demonstrates the feasibility of using an in situ bacterial treatment to enhance gas release and resource recovery from landfill soil containing lignocellulosic waste. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria

Directory of Open Access Journals (Sweden)

Xuezhu Zhu

2016-08-01

Full Text Available Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P1 (Stenotrophomonas sp. and P3 (Pseudomonas sp., which degraded more than 90% of phenanthrene (PHE within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP, PHE, fluorene (FLR, pyrene (PYR, and benzo(apyrene (B(aP as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P1 degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(aP, and strain P3 degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(aP. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days. Compared with strain P1, strain P3 has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria.

The polycyclic aromatic hydrocarbon degradation potential of Gulf of Mexico coastal microbial communities after the Deepwater Horizon oil spill

Directory of Open Access Journals (Sweden)

Anthony D. Kappell

2014-05-01

Full Text Available The Deepwater Horizon (DWH blowout resulted in oil transport, including polycyclic aromatic hydrocarbons (PAHs to the Gulf of Mexico shoreline. The microbial communities of these shorelines are thought to be responsible for the intrinsic degradation of PAHs. To investigate the Gulf Coast beach microbial community response to hydrocarbon exposure, we examined the functional gene diversity, bacterial community composition, and PAH degradation capacity of a heavily oiled and non-oiled beach following the oil exposure. With a non-expression functional gene microarray targeting 539 gene families, we detected 28,748 coding sequences. Of these sequences, 10% were uniquely associated with the severely oil-contaminated beach and 6.0% with the non-oiled beach. There was little variation in the functional genes detected between the two beaches; however the relative abundance of functional genes involved in oil degradation pathways, including PAHs, were greater in the oiled beach. The microbial PAH degradation potentials of both beaches, were tested in mesocosms. Mesocosms were constructed in glass columns using sands with native microbial communities, circulated with artificial sea water and challenged with a mixture of PAHs. The low-molecular weight PAHs, fluorene and naphthalene, showed rapid depletion in all mesocosms while the high-molecular weight benzo[α]pyrene was not degraded by either microbial community. Both the heavily oiled and the non-impacted coastal communities showed little variation in their biodegradation ability for low molecular weight PAHs. Massively-parallel sequencing of 16S rRNA genes from mesocosm DNA showed that known PAH degraders and genera frequently associated with oil hydrocarbon degradation represented a major portion of the bacterial community. The observed similar response by microbial communities from beaches with a different recent history of oil exposure suggests that Gulf Coast beach communities are primed for PAH

Degradation of lucerne stem cell walls by five rumen bacterial species

NARCIS (Netherlands)

Jung, H.G.; Engels, F.M.; Weimer, P.J.

2004-01-01

The rumen bacterial strains Butyrivibrio fibrisolvens H17c, Fibrobacter succinogenes S85, Lachnospira multiparus 40, Ruminococcus albus 7 and R. flavefaciens FD-1 were compared individually and as a five-species mixture with a rumen inoculum for their ability to degrade lucerne (Medicago sativa L.)

Experimental insights into the importance of aquatic bacterial community composition to the degradation of dissolved organic matter

DEFF Research Database (Denmark)

Logue, J.B.; Stedmon, Colin; Kellerman, A.M.

2016-01-01

and ecosystem functioning in that differently structured aquatic bacterial communities differed in their degradation of terrestrially derived DOM. Although the same amount of carbon was processed, both the temporal pattern of degradation and the compounds degraded differed among communities. We, moreover...

In vitro estimation of rumen protein degradability using 35S to label the bacterial mass

International Nuclear Information System (INIS)

Khristov, A.; Aleksandrov, S.; Aleksiev, I.

1994-01-01

An experiment was carried out in order to simplify a previously developed 15 N-method for in vitro estimation of rumen protein degradability. Casein (Cas), whole soybeans (Sb) heated at 120 o C for 20 min (SbTherm) and sunflower (Sfl) were incubated at 39 o C for 4 hours in a water bathshaker with the following media: McDougall's buffer, strained and enriched with particle associated bacteria rumen fluid (2:1), rapidly (maltose, sucrose, glucose) and more slowly (pectin, soluble starch) degradable carbohydrates with final concentration of 815 mg/100 ml and 21.7 μCi/100 ml of 35 S (from Na 2 35 SO 4 ). After the incubation had been ceased, a bacterial fraction was isolated through differential centrifugation and specific activity of bacterial (Bac) and high speed total solids (TS) nitrogen was measured. The ratio was used to calculate bacterial mass in TS and through the Kjeldahl nitrogen concentration in TS - the net bacterial growth (against control vessels without protein). The level of ammonia-N in the supernate after blank correction was used to find the ammonia-N released from protein degradation. The data showed that the rate (and extend) of degradation for the Cas (as a standard protein) was lower compared to those obtained through the 15 N-method but it was higher than the rate derived through another in vitro method. The Cas equivalent of the Sb was higher than the figure we found in a previous experiment with solvent extracted soybean meal suggesting that the 35 S-method underestimated the degradability of the Cas. After being tested on a wider range of foodstuffs, the proposed 35 S-method might be considered as an alternative procedure which is less laborous than the 15 N-method. (author)

Bacterial growth and substrate degradation by BTX-oxidizing culture in response to salt stress.

Science.gov (United States)

Lee, Chi-Yuan; Lin, Ching-Hsing

2006-01-01

Interactions between microbial growth and substrate degradation are important in determining the performance of trickle-bed bioreactors (TBB), especially when salt is added to reduce biomass formation in order to alleviate media clogging. This study was aimed at quantifying salinity effects on bacterial growth and substrate degradation, and at acquiring kinetic information in order to improve the design and operation of TBB. Experiment works began by cultivating a mixed culture in a chemostat reactor receiving artificial influent containing a mixture of benzene, toluene, and xylene (BTX), followed by using the enrichment culture to degrade the individual BTX substrates under a particular salinity, which ranged 0-50 g l(-1) in batch mode. Then, the measured concentrations of biomass and residual substrate versus time were analyzed with the microbial kinetics; moreover, the obtained microbial kinetic constants under various salinities were modeled using noncompetitive inhibition kinetics. For the three substrates the observed bacterial yields appeared to be decreased from 0.51-0.74 to 0.20-0.22 mg mg(-1) and the maximum specific rate of substrate utilization, q, declined from 0.25-0.42 to 0.07-0.11 h(-1), as the salinity increased from 0 to 50 NaCl g l(-1). The NaCl acted as noncompetitive inhibitor, where the modeling inhibitions of the coefficients, K ( T(S)), were 22.7-29.7 g l(-1) for substrate degradation and K ( T(mu)), 13.0-19.0 g l(-1), for biomass formation. The calculated ratios for the bacterial maintenance rate, m (S), to q, further indicated that the percentage energy spent on maintenance increased from 19-24 to 86-91% as salinity level increased from 0 to 50 g l(-1). These results revealed that the bacterial growth was more inhibited than substrate degradation by the BTX oxidizers under the tested salinity levels. The findings from this study demonstrate the potential of applying NaCl salt to control excessive biomass formation in biotrickling filters.

Characterization of para-Nitrophenol-Degrading Bacterial Communities in River Water by Using Functional Markers and Stable Isotope Probing.

Science.gov (United States)

Kowalczyk, Agnieszka; Eyice, Özge; Schäfer, Hendrik; Price, Oliver R; Finnegan, Christopher J; van Egmond, Roger A; Shaw, Liz J; Barrett, Glyn; Bending, Gary D

2015-10-01

Microbial degradation is a major determinant of the fate of pollutants in the environment. para-Nitrophenol (PNP) is an EPA-listed priority pollutant with a wide environmental distribution, but little is known about the microorganisms that degrade it in the environment. We studied the diversity of active PNP-degrading bacterial populations in river water using a novel functional marker approach coupled with [(13)C6]PNP stable isotope probing (SIP). Culturing together with culture-independent terminal restriction fragment length polymorphism analysis of 16S rRNA gene amplicons identified Pseudomonas syringae to be the major driver of PNP degradation in river water microcosms. This was confirmed by SIP-pyrosequencing of amplified 16S rRNA. Similarly, functional gene analysis showed that degradation followed the Gram-negative bacterial pathway and involved pnpA from Pseudomonas spp. However, analysis of maleylacetate reductase (encoded by mar), an enzyme common to late stages of both Gram-negative and Gram-positive bacterial PNP degradation pathways, identified a diverse assemblage of bacteria associated with PNP degradation, suggesting that mar has limited use as a specific marker of PNP biodegradation. Both the pnpA and mar genes were detected in a PNP-degrading isolate, P. syringae AKHD2, which was isolated from river water. Our results suggest that PNP-degrading cultures of Pseudomonas spp. are representative of environmental PNP-degrading populations. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Fabrication of antimicrobial bacterial cellulose–Ag/AgCl nanocomposite using bacteria as versatile biofactory

International Nuclear Information System (INIS)

Liu Chuang; Yang Dong; Wang Yuangui; Shi Jiafu; Jiang Zhongyi

2012-01-01

In nature, a number of nanocomposites are formed through biomineralization-relevant processes under mild conditions. In the present study, a total “biologic” route to fabricate nanocomposite is reported. Non-pathogenic bacteria, Gluconacetobacter xylinum, was utilized as a versatile biofactory, which produced biopolymer bacterial cellulose (BC) and induced the formation of Ag/AgCl nanoparticles, yielding BC–Ag/AgCl nanocomposite. Scanning electron microscopy revealed that nanoparticles with average size of 17.4 nm were randomly embedded into the BC network; transmission electron microscopy and X-ray diffraction confirmed that the nanoparticles were mixtures of face-centered cubic silver and silver chloride nanoparticles. Moreover, the content of silver in the BC nanocomposite is around 0.05 wt%, determined by atomic absorption spectrometry and X-ray photoelectron spectroscopy analysis. The entire process of nanocomposite fabrication was conducted at ambient environment without utilizing toxic agents or producing hazardous products, which is not only environmentally friendly but also with less chances to generate harmful products to human bodies as biomedical materials. The resultant nanocomposite displayed the desirable activity in inhibiting bacterial growth of both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli microorganisms on agar plate and in liquid culture, indicating the potential of the material as antimicrobial wound dressing materials. This work demonstrated the feasibility of using microorganism to fabricate nanocomposite, especially for biomedical materials.

Fabrication of antimicrobial bacterial cellulose-Ag/AgCl nanocomposite using bacteria as versatile biofactory

Energy Technology Data Exchange (ETDEWEB)

Liu Chuang [Tianjin University, Key Laboratory for Green Technology, School of Chemical Engineering and Technology (China); Yang Dong; Wang Yuangui [Tianjin University, Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of Ministry of Education, School of Chemical Engineering and Technology (China); Shi Jiafu; Jiang Zhongyi, E-mail: zhyjiang@tju.edu.cn [Tianjin University, Key Laboratory for Green Technology, School of Chemical Engineering and Technology (China)

2012-08-15

In nature, a number of nanocomposites are formed through biomineralization-relevant processes under mild conditions. In the present study, a total 'biologic' route to fabricate nanocomposite is reported. Non-pathogenic bacteria, Gluconacetobacter xylinum, was utilized as a versatile biofactory, which produced biopolymer bacterial cellulose (BC) and induced the formation of Ag/AgCl nanoparticles, yielding BC-Ag/AgCl nanocomposite. Scanning electron microscopy revealed that nanoparticles with average size of 17.4 nm were randomly embedded into the BC network; transmission electron microscopy and X-ray diffraction confirmed that the nanoparticles were mixtures of face-centered cubic silver and silver chloride nanoparticles. Moreover, the content of silver in the BC nanocomposite is around 0.05 wt%, determined by atomic absorption spectrometry and X-ray photoelectron spectroscopy analysis. The entire process of nanocomposite fabrication was conducted at ambient environment without utilizing toxic agents or producing hazardous products, which is not only environmentally friendly but also with less chances to generate harmful products to human bodies as biomedical materials. The resultant nanocomposite displayed the desirable activity in inhibiting bacterial growth of both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli microorganisms on agar plate and in liquid culture, indicating the potential of the material as antimicrobial wound dressing materials. This work demonstrated the feasibility of using microorganism to fabricate nanocomposite, especially for biomedical materials.

Curcumin Quantum Dots Mediated Degradation of Bacterial Biofilms

Directory of Open Access Journals (Sweden)

Ashish K. Singh

2017-08-01

Full Text Available Bacterial biofilm has been reported to be associated with more than 80% of bacterial infections. Curcumin, a hydrophobic polyphenol compound, has anti-quorum sensing activity apart from having antimicrobial action. However, its use is limited by its poor aqueous solubility and rapid degradation. In this study, we attempted to prepare quantum dots of the drug curcumin in order to achieve enhanced solubility and stability and investigated for its antimicrobial and antibiofilm activity. We utilized a newer two-step bottom up wet milling approach to prepare Curcumin Quantum Dots (CurQDs using acetone as a primary solvent. Minimum inhibitory concentration against select Gram-positive and Gram-negative bacteria was performed. The antibiofilm assay was performed at first using 96-well tissue culture plate and subsequently validated by Confocal Laser Scanning Microscopy. Further, biofilm matrix protein was isolated using formaldehyde sludge and TCA/Acetone precipitation method. Protein extracted was incubated with varying concentration of CurQDs for 4 h and was subjected to SDS–PAGE. Molecular docking study was performed to observe interaction between curcumin and phenol soluble modulins as well as curli proteins. The biophysical evidences obtained from TEM, SEM, UV-VIS, fluorescence, Raman spectroscopy, and zeta potential analysis confirmed the formation of curcumin quantum dots with increased stability and solubility. The MICs of curcumin quantum dots, as observed against both select gram positive and negative bacterial isolates, was observed to be significantly lower than native curcumin particles. On TCP assay, Curcumin observed to be having antibiofilm as well as biofilm degrading activity. Results of SDS–PAGE and molecular docking have shown interaction between biofilm matrix proteins and curcumin. The results indicate that aqueous solubility and stability of Curcumin can be achieved by preparing its quantum dots. The study also demonstrates

Carbon and Hydrogen Stable Isotope Fractionation during Aerobic Bacterial Degradation of Aromatic Hydrocarbons†

Science.gov (United States)

Morasch, Barbara; Richnow, Hans H.; Schink, Bernhard; Vieth, Andrea; Meckenstock, Rainer U.

2002-01-01

13C/12C and D/H stable isotope fractionation during aerobic degradation was determined for Pseudomonas putida strain mt-2, Pseudomonas putida strain F1, Ralstonia pickettii strain PKO1, and Pseudomonas putida strain NCIB 9816 grown with toluene, xylenes, and naphthalene. Different types of initial reactions used by the respective bacterial strains could be linked with certain extents of stable isotope fractionation during substrate degradation. PMID:12324375

Femtosecond Two-Photon Absorption Spectroscopy of Poly(fluorene Derivatives Containing Benzoselenadiazole and Benzothiadiazole

Directory of Open Access Journals (Sweden)

Marcelo Gonçalves Vivas

2017-05-01

Full Text Available We have investigated the molecular structure and two-photon absorption (2PA properties relationship of two push–pull poly(fluorene derivatives containing benzoselenadiazole and benzothiadiazole units. For that, we have used the femtosecond wavelength-tunable Z-scan technique with a low repetition rate (1 kHz and an energy per pulse on the order of nJ. Our results show that both 2PA spectra present a strong 2PA (around 600 GM (1 GM = 1 × 10−50 cm4·s·photon−1 band at around 720 nm (transition energy 3.45 eV ascribed to the strongly 2PA-allowed 1Ag-like → mAg-like transition, characteristic of poly(fluorene derivatives. Another 2PA band related to the intramolecular charge transfer was also observed at around 900 nm (transition energy 2.75 eV. In both 2PA bands, we found higher 2PA cross-section values for the poly(fluorene containing benzothiadiazole unit. This outcome was explained through the higher charge redistribution at the excited state caused by the benzothiadiazole group as compared to the benzoselenadiazole and confirmed by means of solvatochromic Stokes shift measurements. To shed more light on these results, we employed the sum-over-states approach within the two-energy level model to estimate the maximum permanent dipole moment change related to the intramolecular charge transfer transition.

Degradation and utilization of polycyclic aromatic hydrocarbons by indigenous soil bacteria

International Nuclear Information System (INIS)

Stetzenbach, L.D.A.

1986-01-01

The persistence of industrially derived polycyclic aromatic hydrocarbons in the subsurface may be significantly affected by the metabolism of soil bacteria. This study was conducted to determine the ability of indigenous soil bacteria to decrease the concentration of four polycyclic aromatic hydrocarbons (naphthalene, fluorene, anthracene, and pyrene) and to utilize the compounds as a substrate for growth. Soil cores from petroleum contaminated and noncontaminated sites contained 10 5 -10 7 viable microorganisms per gram dryweight of soil. Gram negative rod-shaped bacteria predominated. Decreases in the concentration of the four polycyclic aromatic hydrocarbons were observed during incubation with bacterial isolates in aqueous suspension by the use of high performance liquid chromatography. Corresponding increases in bacterial numbers indicated utilization of the compounds as a carbon source. Soil samples from the contaminated sites contained greater numbers of bacteria utilizing anthracene and pyrene than soil samples from uncontaminated sites. Degradation rates of the four polycyclic aromatic hydrocarbons were related to the compound, its concentration, and the bacterium. Biodegradation of pyrene was positively correlated with the presence of oxygen. Pyrene was biodegraded by an Acinetobacter sp. under aerobic conditions but not under anaerobic or microaerophilic conditions. Studies with radiolabeled 14 C-anthracene demonstrated utilization of the labeled carbon as a source of carbon by viable bacterial cells in aqueous suspension. Incorporation of 14 C into cellular biomass however was not observed during incubation of 14 C-anthracene in soil

Degradation of paracetamol by pure bacterial cultures and their microbial consortium.

Science.gov (United States)

Zhang, Lili; Hu, Jun; Zhu, Runye; Zhou, Qingwei; Chen, Jianmeng

2013-04-01

Three bacterial strains utilizing paracetamol as the sole carbon, nitrogen, and energy source were isolated from a paracetamol-degrading aerobic aggregate, and assigned to species of the genera Stenotrophomonas and Pseudomonas. The Stenotrophomonas species have not included any known paracetamol degraders until now. In batch cultures, the organisms f1, f2, and fg-2 could perform complete degradation of paracetamol at concentrations of 400, 2,500, and 2,000 mg/L or below, respectively. A combination of three microbial strains resulted in significantly improved degradation and mineralization of paracetamol. The co-culture was able to use paracetamol up to concentrations of 4,000 mg/L, and mineralized 87.1 % of the added paracetamol at the initial of 2,000 mg/L. Two key metabolites of the biodegradation pathway of paracetamol, 4-aminophenol, and hydroquinone were detected. Paracetamol was degraded predominantly via 4-aminophenol to hydroquinone with subsequent ring fission, suggesting new pathways for paracetamol-degrading bacteria. The degradation of paracetamol could thus be performed by the single isolates, but is stimulated by a synergistic interaction of the three-member consortium, suggesting a possible complementary interaction among the various isolates. The exact roles of each of the strains in the consortium need to be further elucidated.

Predictable bacterial composition and hydrocarbon degradation in Arctic soils following diesel and nutrient disturbance

Science.gov (United States)

Bell, Terrence H; Yergeau, Etienne; Maynard, Christine; Juck, David; Whyte, Lyle G; Greer, Charles W

2013-01-01

Increased exploration and exploitation of resources in the Arctic is leading to a higher risk of petroleum contamination. A number of Arctic microorganisms can use petroleum for growth-supporting carbon and energy, but traditional approaches for stimulating these microorganisms (for example, nutrient addition) have varied in effectiveness between sites. Consistent environmental controls on microbial community response to disturbance from petroleum contaminants and nutrient amendments across Arctic soils have not been identified, nor is it known whether specific taxa are universally associated with efficient bioremediation. In this study, we contaminated 18 Arctic soils with diesel and treated subsamples of each with monoammonium phosphate (MAP), which has successfully stimulated degradation in some contaminated Arctic soils. Bacterial community composition of uncontaminated, diesel-contaminated and diesel+MAP soils was assessed through multiplexed 16S (ribosomal RNA) rRNA gene sequencing on an Ion Torrent Personal Genome Machine, while hydrocarbon degradation was measured by gas chromatography analysis. Diversity of 16S rRNA gene sequences was reduced by diesel, and more so by the combination of diesel and MAP. Actinobacteria dominated uncontaminated soils with soils, and this pattern was exaggerated following disturbance. Degradation with and without MAP was predictable by initial bacterial diversity and the abundance of specific assemblages of Betaproteobacteria, respectively. High Betaproteobacteria abundance was positively correlated with high diesel degradation in MAP-treated soils, suggesting this may be an important group to stimulate. The predictability with which bacterial communities respond to these disturbances suggests that costly and time-consuming contaminated site assessments may not be necessary in the future. PMID:23389106

Degradation and mineralization of high-molecular-weight polycyclic aromatic hydrocarbons by defined fungal-bacterial cocultures

International Nuclear Information System (INIS)

Boonchan, S.; Britz, M.L.; Stanley, G.A.

2000-01-01

This study investigated the biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) in liquid media and soil by bacteria (Stenotrophomonas maltophilia VUN 10,010 and bacterial consortium VUN 10,009) and a fungus (Penicillium janthinellum VUO 10,201) that were isolated from separate creosote- and manufactured-gas plant-contaminated soils. The bacteria could use pyrene as their sole carbon and energy source in a basal salts medium (BSM) and mineralized significant amounts of benzo[a]pyrene cometabolically when pyrene was also present in BSM. P. janthinellum VUO 10,201 could not utilize any high-molecular-weight PAH as sole carbon and energy source but could partially degrade these if cultured in a nutrient broth. Although small amounts of chrysene, benz[a]pyrene, and dibenz[a,h]anthracene were degraded by axenic cultures of these isolates in BSM containing a single PAH, such conditions did not support significant microbial growth or PAH mineralization. However, significant degradation of, and microbial growth on, pyrene, chrysene, benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene, each as a single PAH in BSM, occurred when P. janthinellum VUO 10,201 and either bacterial consortium VUN 10,009 or S. maltophilia VUN 10,010 were combined in the one culture, i.e., fungal-bacterial cocultures: 25% of the benzo[a]pyrene was mineralized to CO 2 by these cocultures over 49 days, accompanied by transient accumulation and disappearance of intermediates detected by high-pressure liquid chromatography. Inoculation of fungal-bacterial cocultures into PAH-contaminated soil resulted in significantly improved degradation of high-molecular-weight PAHs, benzo[a]pyrene mineralization, and reduction in the mutagenicity of organic soil extracts, compared with the indigenous microbes and soil amended with only axenic inocula

Synthesis of Dendrimer Containing Dialkylated-fluorene Unit as a Core Chromophore via Click Chemistry

International Nuclear Information System (INIS)

Han, Seung Choul; Lee, Jae Wook; Jin, Sung Ho

2012-01-01

The convergent synthetic strategy for the emissive dendrimers having the chromophore at core via the coppercatalyzed 1,3-dipolar cycloaddition reaction between alkyne and azide was described. 2,7-Diazido-9,9-dioctyl- 9H-fluorene, designed to serve as the core in dendrimer, was stitched with the alkyne-functionalized Frechettype and PAMAM dendrons by the click chemistry leading to the formation of the corresponding fluorescent dendrimers in high yields. The preliminary photoluminescence studies indicated that 2,7-diazido-9,9-dioctyl- 9H-fluorene showed no fluorescence due to the quenching effect from the electron-rich α-nitrogen of the azido group but the dendrimers fluoresced due to the elimination of the quenching through the formation of the triazole ring

Mass culture strategy for bacterial yeast co-culture for degradation of petroleum hydrocarbons in marine environment.

Science.gov (United States)

Priya, Anchal; Mandal, Ajoy K; Ball, Andrew S; Manefield, Mike; Lal, Banwari; Sarma, Priyangshu M

2015-11-15

In the present study a metabolically versatile co-culture with two Bacilli and one yeast strain was developed using enrichment culture techniques. The developed co-culture had affinity to degrade both aliphatic and aromatic fractions of petroleum crude oil. Degradation kinetics was established for designing the fermentation protocol of the co-culture. The developed mass culture strategy led to achieve the reduction in surface tension (26dynescm(-1) from 69 dynescm(-1)) and degradation of 67% in bench scale experiments. The total crude oil degradation of 96% was achieved in 4000l of natural seawater after 28days without adding any nutrients. The survival of the augmented co-culture was maintained (10(9)cellsml(-1)) in contaminated marine environment. The mass culture protocol devised for the bioaugmentation was a key breakthrough that was subsequently used for pilot scale studies with 100l and 4000l of natural seawater for potential application in marine oil spills. Copyright © 2015 Elsevier Ltd. All rights reserved.

EDTA addition enhances bacterial respiration activities and hydrocarbon degradation in bioaugmented and non-bioaugmented oil-contaminated desert soils.

Science.gov (United States)

Al Kharusi, Samiha; Abed, Raeid M M; Dobretsov, Sergey

2016-03-01

The low number and activity of hydrocarbon-degrading bacteria and the low solubility and availability of hydrocarbons hamper bioremediation of oil-contaminated soils in arid deserts, thus bioremediation treatments that circumvent these limitations are required. We tested the effect of Ethylenediaminetetraacetic acid (EDTA) addition, at different concentrations (i.e. 0.1, 1 and 10 mM), on bacterial respiration and biodegradation of Arabian light oil in bioaugmented (i.e. with the addition of exogenous alkane-degrading consortium) and non-bioaugmented oil-contaminated desert soils. Post-treatment shifts in the soils' bacterial community structure were monitored using MiSeq sequencing. Bacterial respiration, indicated by the amount of evolved CO2, was highest at 10 mM EDTA in bioaugmented and non-bioaugmented soils, reaching an amount of 2.2 ± 0.08 and 1.6 ± 0.02 mg-CO2 g(-1) after 14 days of incubation, respectively. GC-MS revealed that 91.5% of the C14-C30 alkanes were degraded after 42 days when 10 mM EDTA and the bacterial consortium were added together. MiSeq sequencing showed that 78-91% of retrieved sequences in the original soil belonged to Deinococci, Alphaproteobacteria, Gammaproteobacteia and Bacilli. The same bacterial classes were detected in the 10 mM EDTA-treated soils, however with slight differences in their relative abundances. In the bioaugmented soils, only Alcanivorax sp. MH3 and Parvibaculum sp. MH21 from the exogenous bacterial consortium could survive until the end of the experiment. We conclude that the addition of EDTA at appropriate concentrations could facilitate biodegradation processes by increasing hydrocarbon availability to microbes. The addition of exogenous oil-degrading bacteria along with EDTA could serve as an ideal solution for the decontamination of oil-contaminated desert soils. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biodegradation of low and high molecular weight hydrocarbons in petroleum refinery wastewater by a thermophilic bacterial consortium.

Science.gov (United States)

Pugazhendi, Arulazhagan; Abbad Wazin, Hadeel; Qari, Huda; Basahi, Jalal Mohammad Al-Badry; Godon, Jean Jacques; Dhavamani, Jeyakumar

2017-10-01

Clean-up of contaminated wastewater remains to be a major challenge in petroleum refinery. Here, we describe the capacity of a bacterial consortium enriched from crude oil drilling site in Al-Khobar, Saudi Arabia, to utilize polycyclic aromatic hydrocarbons (PAHs) as sole carbon source at 60°C. The consortium reduced low molecular weight (LMW; naphthalene, phenanthrene, fluorene and anthracene) and high molecular weight (HMW; pyrene, benzo(e)pyrene and benzo(k)fluoranthene) PAH loads of up to 1.5 g/L with removal efficiencies of 90% and 80% within 10 days. PAH biodegradation was verified by the presence of PAH metabolites and evolution of carbon dioxide (90 ± 3%). Biodegradation led to a reduction of the surface tension to 34 ± 1 mN/m thus suggesting biosurfactant production by the consortium. Phylogenetic analysis of the consortium revealed the presence of the thermophilic PAH degrader Pseudomonas aeruginosa strain CEES1 (KU664514) and Bacillus thermosaudia (KU664515) strain CEES2. The consortium was further found to treat petroleum wastewater in continuous stirred tank reactor with 96 ± 2% chemical oxygen demand removal and complete PAH degradation in 24 days.

Draft genome sequence of Micrococcus luteus strain O'Kane implicates metabolic versatility and the potential to degrade polyhydroxybutyrates.

Science.gov (United States)

Hanafy, Radwa A; Couger, M B; Baker, Kristina; Murphy, Chelsea; O'Kane, Shannon D; Budd, Connie; French, Donald P; Hoff, Wouter D; Youssef, Noha

2016-09-01

Micrococcus luteus is a predominant member of skin microbiome. We here report on the genomic analysis of Micrococcus luteus strain O'Kane that was isolated from an elevator. The partial genome assembly of Micrococcus luteus strain O'Kane is 2.5 Mb with 2256 protein-coding genes and 62 RNA genes. Genomic analysis revealed metabolic versatility with genes involved in the metabolism and transport of glucose, galactose, fructose, mannose, alanine, aspartate, asparagine, glutamate, glutamine, glycine, serine, cysteine, methionine, arginine, proline, histidine, phenylalanine, and fatty acids. Genomic comparison to other M. luteus representatives identified the potential to degrade polyhydroxybutyrates, as well as several antibiotic resistance genes absent from other genomes.

Scalable synthesis of 5,11-diethynylated indeno[1,2-b]fluorene-6,12-diones and exploration of their solid state packing

Directory of Open Access Journals (Sweden)

Bradley D. Rose

2014-09-01

Full Text Available We report a new synthetic route to 5,11-disubstituted indeno[1,2-b]fluorene-6,12-diones that is amenable to larger scale reactions, allowing for the preparation of gram amounts of material. With this new methodology, we explored the effects on crystal packing morphology for the indeno[1,2-b]fluorene-6,12-diones by varying the substituents on the silylethynyl groups.

Simultaneous Microcystis Algicidal and Microcystin Degrading Capability by a Single Acinetobacter Bacterial Strain.

Science.gov (United States)

Li, Hong; Ai, Hainan; Kang, Li; Sun, Xingfu; He, Qiang

2016-11-01

Measures for removal of toxic harmful algal blooms often cause lysis of algal cells and release of microcystins (MCs). In this study, Acinetobacter sp. CMDB-2 that exhibits distinct algal lysing activity and MCs degradation capability was isolated. The physiological response and morphological characteristics of toxin-producing Microcystis aeruginosa, the dynamics of intra- and extracellular MC-LR concentration were studied in an algal/bacterial cocultured system. The results demonstrated that Acinetobacter sp. CMDB-2 caused thorough decomposition of algal cells and impairment of photosynthesis within 24 h. Enhanced algal lysis and MC-LR release appeared with increasing bacterial density from 1 × 10 3 to 1 × 10 7 cells/mL; however, the MC-LR was reduced by nearly 94% within 14 h irrespective of bacterial density. Measurement of extracellular and intracellular MC-LR revealed that the toxin was decreased by 92% in bacterial cell incubated systems relative to control and bacterial cell-free filtrate systems. The results confirmed that the bacterial metabolite caused 92% lysis of Microcystis aeruginosa cells, whereas the bacterial cells were responsible for approximately 91% reduction of MC-LR. The joint efforts of the bacterium and its metabolite accomplished the sustainable removal of algae and MC-LR. This is the first report of a single bacterial strain that achieves these dual actions.

The synthesis, structure, and properties of 5,6,11,12-tetraarylindeno[1,2-b]fluorenes and their applications as donors for organic photovoltaic devices

KAUST Repository

Lo, Yuan-Chih; Ting, Hao-Chun; Li, Ya-Ze; Li, Yi-Hua; Liu, Shun-Wei; Huang, Kuo-Wei; Wong, Ken-Tsung

2016-01-01

The synthesis, structure, and properties of three new 5,6,11,12-tetraarylindeno[1,2-b]fluorenes are reported. The highly twisted conformations between an indeno[1,2-b]fluorene core and peripheral aryl substitutions endow these indeno[1,2-b]fluorene derivatives with good photostability for use as electron donors for vacuum-deposited photovoltaic devices. The optimized device based on a TAInF2 donor blended with C70 as an electron acceptor produces a high open-circuit voltage (>0.9 V) and a power conversion efficiency of 2.91%. This work demonstrates the first application of an indenofluorene derivative as an electron donor in organic solar cells.

The synthesis, structure, and properties of 5,6,11,12-tetraarylindeno[1,2-b]fluorenes and their applications as donors for organic photovoltaic devices

KAUST Repository

Lo, Yuan-Chih

2016-12-01

The synthesis, structure, and properties of three new 5,6,11,12-tetraarylindeno[1,2-b]fluorenes are reported. The highly twisted conformations between an indeno[1,2-b]fluorene core and peripheral aryl substitutions endow these indeno[1,2-b]fluorene derivatives with good photostability for use as electron donors for vacuum-deposited photovoltaic devices. The optimized device based on a TAInF2 donor blended with C70 as an electron acceptor produces a high open-circuit voltage (>0.9 V) and a power conversion efficiency of 2.91%. This work demonstrates the first application of an indenofluorene derivative as an electron donor in organic solar cells.

Bioremediation of crude oil polluted seawater by a hydrocarbon-degrading bacterial strain immobilized on chitin and chitosan flakes

International Nuclear Information System (INIS)

Gentili, A.R.; Cubitto, M.A.; Ferrero, M.; Rodriguez, M.S.

2006-01-01

In this laboratory-scale study, we examined the potential of chitin and chitosan flakes obtained from shrimp wastes as carrier material for a hydrocarbon-degrading bacterial strain. Flakes decontamination, immobilization conditions and the survival of the immobilized bacterial strain under different storage temperatures were evaluated. The potential of immobilized hydrocarbon-degrading bacterial strain for crude oil polluted seawater bioremediation was tested in seawater microcosms. In terms of removal percentage of crude oil after 15 days, the microcosms treated with the immobilized inoculants proved to be the most successful. The inoculants formulated with chitin and chitosan as carrier materials improved the survival and the activity of the immobilized strain. It is important to emphasize that the inoculants formulated with chitin showed the best performance during storage and seawater bioremediation. (author)

Investigation of synthesis, thermal properties and curing kinetics of fluorene diamine-based benzoxazine by using two curing kinetic methods

International Nuclear Information System (INIS)

He, Xuan-yu; Wang, Jun; Ramdani, Noureddine; Liu, Wen-bin; Liu, Li-jia; Yang, Lei

2013-01-01

Graphical abstract: - Highlights: • A novel diamine-based benzoxazine monomer containing aryl ether and bulky fluorene groups (BEF-p) is synthesized. • Kinetic parameters can be calculated by Starink-LSR method and direct LSR method. • Cure reaction could be successfully described with the autocatalytic model. • The poly(BEF-p) exhibits high T g and superior thermal stability. • Aryl ether linkages had little influence on the thermal stability. - Abstract: A novel diamine-based benzoxazine monomer containing aryl ether and bulky fluorene groups (BEF-p) was prepared from the reaction of 9,9-bis-[4-(p-aminophenoxy)-phenyl]fluorene with paraformaldehyde and phenol. The chemical structure of monomer was confirmed by Fourier-transform infrared (FTIR) and 1 H and 13 C nuclear magnetic resonance spectroscopy ( 1 H and 13 C NMR). The polymerization behavior of monomer was analyzed by differential scanning calorimetry (DSC) and FTIR. The curing kinetics was studied by non-isothermal DSC, and the kinetic parameters were determined. The autocatalytic model based on two kinetic methods (Starink-LSR method and direct LSR method) showed good agreement with experimental results. The thermal and mechanical properties of poly(BEF-p) were evaluated with DSC, dynamic mechanical thermal analysis (DMTA), and thermogravimetric analysis (TGA). The results showed that the cured polymer exhibited higher glass transition temperature (T g ) and better thermal stability compared with diaminodiphenylmethane-based benzoxazine(P-ddm), and was slightly lower than those of fluorene diamine-phenol-based polybenzoxazine (poly(BF-p))

Naphthalene degradation by bacterial consortium (DV-AL) developed from Alang-Sosiya ship breaking yard, Gujarat, India.

Science.gov (United States)

Patel, Vilas; Jain, Siddharth; Madamwar, Datta

2012-03-01

Naphthalene degrading bacterial consortium (DV-AL) was developed by enrichment culture technique from sediment collected from the Alang-Sosiya ship breaking yard, Gujarat, India. The 16S rRNA gene based molecular analyzes revealed that the bacterial consortium (DV-AL) consisted of four strains namely, Achromobacter sp. BAB239, Pseudomonas sp. DV-AL2, Enterobacter sp. BAB240 and Pseudomonas sp. BAB241. Consortium DV-AL was able to degrade 1000 ppm of naphthalene in Bushnell Haas medium (BHM) containing peptone (0.1%) as co-substrate with an initial pH of 8.0 at 37°C under shaking conditions (150 rpm) within 24h. Maximum growth rate and naphthalene degradation rate were found to be 0.0389 h(-1) and 80 mg h(-1), respectively. Consortium DV-AL was able to utilize other aromatic and aliphatic hydrocarbons such as benzene, phenol, carbazole, petroleum oil, diesel fuel, and phenanthrene and 2-methyl naphthalene as sole carbon source. Consortium DV-AL was also efficient to degrade naphthalene in the presence of other pollutants such as petroleum hydrocarbons and heavy metals. Copyright © 2011 Elsevier Ltd. All rights reserved.

Draft genome sequence of Micrococcus luteus strain O'Kane implicates metabolic versatility and the potential to degrade polyhydroxybutyrates

Directory of Open Access Journals (Sweden)

Radwa A. Hanafy

2016-09-01

Full Text Available Micrococcus luteus is a predominant member of skin microbiome. We here report on the genomic analysis of Micrococcus luteus strain O'Kane that was isolated from an elevator. The partial genome assembly of Micrococcus luteus strain O'Kane is 2.5 Mb with 2256 protein-coding genes and 62 RNA genes. Genomic analysis revealed metabolic versatility with genes involved in the metabolism and transport of glucose, galactose, fructose, mannose, alanine, aspartate, asparagine, glutamate, glutamine, glycine, serine, cysteine, methionine, arginine, proline, histidine, phenylalanine, and fatty acids. Genomic comparison to other M. luteus representatives identified the potential to degrade polyhydroxybutyrates, as well as several antibiotic resistance genes absent from other genomes.

BACTERIAL CONSORTIUM

Directory of Open Access Journals (Sweden)

Payel Sarkar

2013-01-01

Full Text Available Petroleum aromatic hydrocarbons like benzen e, toluene, ethyl benzene and xylene, together known as BTEX, has almost the same chemical structure. These aromatic hydrocarbons are released as pollutants in th e environment. This work was taken up to develop a solvent tolerant bacterial cons ortium that could degrade BTEX compounds as they all share a common chemical structure. We have isolated almost 60 different types of bacterial strains from different petroleum contaminated sites. Of these 60 bacterial strains almost 20 microorganisms were screene d on the basis of capability to tolerate high concentration of BTEX. Ten differe nt consortia were prepared and the compatibility of the bacterial strains within the consortia was checked by gram staining and BTEX tolerance level. Four successful mi crobial consortia were selected in which all the bacterial strains concomitantly grew in presence of high concentration of BTEX (10% of toluene, 10% of benzene 5% ethyl benzene and 1% xylene. Consortium #2 showed the highest growth rate in pr esence of BTEX. Degradation of BTEX by consortium #2 was monitored for 5 days by gradual decrease in the volume of the solvents. The maximum reduction observed wa s 85% in 5 days. Gas chromatography results also reveal that could completely degrade benzene and ethyl benzene within 48 hours. Almost 90% degradation of toluene and xylene in 48 hours was exhibited by consortium #2. It could also tolerate and degrade many industrial solvents such as chloroform, DMSO, acetonitrile having a wide range of log P values (0.03–3.1. Degradation of aromatic hydrocarbon like BTEX by a solvent tolerant bacterial consortium is greatly significant as it could degrade high concentration of pollutants compared to a bacterium and also reduces the time span of degradation.

Aerobic cyanide degradation by bacterial isolates from cassava factory wastewater.

Science.gov (United States)

Kandasamy, Sujatha; Dananjeyan, Balachandar; Krishnamurthy, Kumar; Benckiser, Gero

2015-01-01

Ten bacterial strains that utilize cyanide (CN) as a nitrogen source were isolated from cassava factory wastewater after enrichment in a liquid media containing sodium cyanide (1 mM) and glucose (0.2% w/v). The strains could tolerate and grow in cyanide concentrations of up to 5 mM. Increased cyanide levels in the media caused an extension of lag phase in the bacterial growth indicating that they need some period of acclimatisation. The rate of cyanide removal by the strains depends on the initial cyanide and glucose concentrations. When initial cyanide and glucose concentrations were increased up to 5 mM, cyanide removal rate increased up to 63 and 61 per cent by Bacillus pumilus and Pseudomonas putida. Metabolic products such as ammonia and formate were detected in culture supernatants, suggesting a direct hydrolytic pathway without an intermediate formamide. The study clearly demonstrates the potential of aerobic treatment with cyanide degrading bacteria for cyanide removal in cassava factory wastewaters.

Land-based salmon aquacultures change the quality and bacterial degradation of riverine dissolved organic matter

DEFF Research Database (Denmark)

Kamjunke, Norbert; Nimptsch, Jorge; Harir, Mourad

2017-01-01

characterization of aquaculture DOM quality and its bacterial degradation using four salmon aquacultures in Chile. Fluorescence measurements, ultrahigh-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy of the DOM revealed specific and extensive molecular alterations caused by aquacultures...

Bacterial diversity and reductive dehalogenase redundancy in a 1,2-dichloroethane-degrading bacterial consortium enriched from a contaminated aquifer

Directory of Open Access Journals (Sweden)

Wittebolle Lieven

2010-02-01

Full Text Available Abstract Background Bacteria possess a reservoir of metabolic functionalities ready to be exploited for multiple purposes. The use of microorganisms to clean up xenobiotics from polluted ecosystems (e.g. soil and water represents an eco-sustainable and powerful alternative to traditional remediation processes. Recent developments in molecular-biology-based techniques have led to rapid and accurate strategies for monitoring and identification of bacteria and catabolic genes involved in the degradation of xenobiotics, key processes to follow up the activities in situ. Results We report the characterization of the response of an enriched bacterial community of a 1,2-dichloroethane (1,2-DCA contaminated aquifer to the spiking with 5 mM lactate as electron donor in microcosm studies. After 15 days of incubation, the microbial community structure was analyzed. The bacterial 16S rRNA gene clone library showed that the most represented phylogenetic group within the consortium was affiliated with the phylum Firmicutes. Among them, known degraders of chlorinated compounds were identified. A reductive dehalogenase genes clone library showed that the community held four phylogenetically-distinct catalytic enzymes, all conserving signature residues previously shown to be linked to 1,2-DCA dehalogenation. Conclusions The overall data indicate that the enriched bacterial consortium shares the metabolic functionality between different members of the microbial community and is characterized by a high functional redundancy. These are fundamental features for the maintenance of the community's functionality, especially under stress conditions and suggest the feasibility of a bioremediation treatment with a potential prompt dehalogenation and a process stability over time.

N-(Fluoren-9-ylmethoxycarbonyl-l-aspartic acid 4-tert-butyl ester

Directory of Open Access Journals (Sweden)

Kazuhiko Yamada

2009-11-01

Full Text Available The bond distances and bond angles of the title compound, C23H25NO6, are consistent with values typically found for fluoren-9-ylmethoxycarbonyl-protected amino acids. The conformations of the backbone and the side chain are slightly different from those of l-aspartic acid. The crystal structure exhibits two intermolecular hydrogen bonds, forming a two-dimensional sheet structure parallel to the ab plane.

Evidence and Role for Bacterial Mucin Degradation in Cystic Fibrosis Airway Disease

Science.gov (United States)

Flynn, Jeffrey M.; Niccum, David; Dunitz, Jordan M.

2016-01-01

Chronic lung infections in cystic fibrosis (CF) patients are composed of complex microbial communities that incite persistent inflammation and airway damage. Despite the high density of bacteria that colonize the lower airways, nutrient sources that sustain bacterial growth in vivo, and how those nutrients are derived, are not well characterized. In this study, we examined the possibility that mucins serve as an important carbon reservoir for the CF lung microbiota. While Pseudomonas aeruginosa was unable to efficiently utilize mucins in isolation, we found that anaerobic, mucin-fermenting bacteria could stimulate the robust growth of CF pathogens when provided intact mucins as a sole carbon source. 16S rRNA sequencing and enrichment culturing of sputum also identified that mucin-degrading anaerobes are ubiquitous in the airways of CF patients. The collective fermentative metabolism of these mucin-degrading communities in vitro generated amino acids and short chain fatty acids (propionate and acetate) during growth on mucin, and the same metabolites were also found in abundance within expectorated sputum. The significance of these findings was supported by in vivo P. aeruginosa gene expression, which revealed a heightened expression of genes required for the catabolism of propionate. Given that propionate is exclusively derived from bacterial fermentation, these data provide evidence for an important role of mucin fermenting bacteria in the carbon flux of the lower airways. More specifically, microorganisms typically defined as commensals may contribute to airway disease by degrading mucins, in turn providing nutrients for pathogens otherwise unable to efficiently obtain carbon in the lung. PMID:27548479

Convenient solvatochromic probes for the determination of solvent properties: {beta}-carotene and 2-chloro-7-nitro-9H-fluorene

Energy Technology Data Exchange (ETDEWEB)

Seoud, Omar A. El; Pires, Paulo A.R.; Loffredo, Carina; Imran, Muhammad; Pulcini, Paolo D.; Correa, Michelle F.; Mustafa, Rizwana, E-mail: elseoud@iq.usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Quimica

2013-07-15

Solvent dipolarity/polarizability (SDP) has been previously calculated from the UV-Vis spectra of 2-(N,N-dimethylamino)-7-nitro-9H-fluorene and 2-fluoro-7-nitro-9H- fluorene. Based on theoretical calculations (23 solvents) and experimental data (56 solvents), it is shown that 2-chloro-7-nitro-9H-fluorene (commercially available) can be conveniently employed for the calculation of this property, instead of its 2-fluoro-7-nitro counterpart. The splitting of SDP into its components (solvent dipolarity (SD) and polarizability (SP)) requires the use of a synthetic polyene compound whose synthesis is laborious, involving 15 steps. Our research group has recently shown that the natural dye {beta}-carotene can be conveniently employed for the determination of SP, allowing the calculation of SD. Using these solvatochromic probes, SDP, SP and SD for a series of 1-bromo alkanes were calculated. For several homologous series, the dependence of solvent SDP (SD and SP for one series) on the number of carbon atoms in the 1-alkyl- or acyl-group was calculated and discussed. (author)

Dissolution and degradation of crude oil droplets by different bacterial species and consortia by microcosm microfluidics

Science.gov (United States)

Jalali, Maryam; Sheng, Jian

2017-11-01

Bacteria are involved in cleanup and degradation of crude oil in polluted marine and soil environments. A number of bacterial species have been identified for consuming petroleum hydrocarbons with diverse metabolic capabilities. We conducted laboratory experiments to investigate bacterial consumption by monitoring the volume change to oil droplets as well as effects of oil droplet size on this process. To conduct our study, we developed a micro-bioassay containing an enclosed chamber with bottom substrate printed with stationary oil microdroplets and a digital holographic interferometer (DHI). The morphology of microdroplets was monitored in real time over 100 hours and instantaneous flow field was also measured by digital holographic microscope. The substrates with printed oil droplets were further evaluated with atomic force microscopy (AFM) at the end of each experiment. Three different bacteria species, Pseudomonas sp, Alcanivorax borkumensis, and Marinobacter hydrocarbonoclasticus, as well as six bacterial consortia were used in this study. The results show that droplets smaller than 20µm in diameter are not subject to bacterial degradation and the volume of droplet did not change beyond dissolution. Substantial species-specific behaviors have been observed in isolates. The experiments of consortia and various flow shears on biodegradation and dissolution are ongoing and will be reported.

Tunable properties of novel tetra-functional fluorene-based benzoxazines from mixed amines: Synthesis, characterization and curing kinetics

International Nuclear Information System (INIS)

Feng, Tiantian; Wang, Jun; Pan, Lan; Derradji, Mehdi; Ramdani, Noureddine; Liu, Wenbin; Zhou, Haoran

2016-01-01

Highlights: • Synthesis of tetra-functional fluorene-based benzoxazines with tunable properties. • Cure reaction could be successfully described with the autocatalytic model. • The benzoxazines show an excellent heat resistance with T_g of 291–307 °C. • The benzoxazines exhibit good thermal stability with T_5 over 340 °C. - Abstract: A series of tetra-functional fluorene-based benzoxazines containing both flexible linear aliphatic chain and rigid aromatic structure in their backbones were synthesized using mixed amines such as aniline and n-octylamine, 2,7-dihydroxy-9,9-bis-(4-hydroxyphenyl)fluorene (THPF) and paraformaldehyde as raw materials via Mannich reaction. The prepared benzoxazine monomers were identified by fourier transform infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance ("1H NMR). In addition, the curing behavior, curing kinetics and rheological properties of these monomers as well as the thermal and mechanical properties of their cured resins were studied using a rheometer, differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), and dynamic thermomechanical analyzer (DMA). The newly developed benzoxazines show good processibility, excellent thermal stability and high glass transition temperature (T_g) values ranging from 291 to 307 °C. By varying the proportion of n-octylamine to aniline, the properties of these resins are tuned.

Influence of PAHs among other coastal environmental variables on total and PAH-degrading bacterial communities.

Science.gov (United States)

Sauret, Caroline; Tedetti, Marc; Guigue, Catherine; Dumas, Chloé; Lami, Raphaël; Pujo-Pay, Mireille; Conan, Pascal; Goutx, Madeleine; Ghiglione, Jean-François

2016-03-01

We evaluated the relative impact of anthropogenic polycyclic aromatic hydrocarbons (PAHs) among biogeochemical variables on total, metabolically active, and PAH bacterial communities in summer and winter in surface microlayer (SML) and subsurface seawaters (SSW) across short transects along the NW Mediterranean coast from three harbors, one wastewater effluent, and one nearshore observatory reference site. At both seasons, significant correlations were found between dissolved total PAH concentrations and PAH-degrading bacteria that formed a gradient from the shore to nearshore waters. Accumulation of PAH degraders was particularly high in the SML, where PAHs accumulated. Harbors and wastewater outfalls influenced drastically and in a different way the total and active bacterial community structure, but they only impacted the communities from the nearshore zone (PAH concentrations on the spatial and temporal dynamic of total and active communities in this area, but this effect was putted in perspective by the importance of other biogeochemical variables.

Potential Environmental Factors Affecting Oil-Degrading Bacterial Populations in Deep and Surface Waters of the Northern Gulf of Mexico.

Science.gov (United States)

Liu, Jiqing; Bacosa, Hernando P; Liu, Zhanfei

2016-01-01

Understanding bacterial community dynamics as a result of an oil spill is important for predicting the fate of oil released to the environment and developing bioremediation strategies in the Gulf of Mexico. In this study, we aimed to elucidate the roles of temperature, water chemistry (nutrients), and initial bacterial community in selecting oil degraders through a series of incubation experiments. Surface (2 m) and bottom (1537 m) waters, collected near the Deepwater Horizon site, were amended with 200 ppm light Louisiana sweet crude oil and bacterial inoculums from surface or bottom water, and incubated at 4 or 24°C for 50 days. Bacterial community and residual oil were analyzed by pyrosequencing and gas chromatography-mass spectrometry (GC-MS), respectively. The results showed that temperature played a key role in selecting oil-degrading bacteria. Incubation at 4°C favored the development of Cycloclasticus, Pseudoalteromonas , Sulfitobacter , and Reinekea , while 24°C incubations enhanced Oleibacter, Thalassobius, Phaeobacter, and Roseobacter. Water chemistry and the initial community also had potential roles in the development of hydrocarbon-degrading bacterial communities. Pseudoalteromonas , Oleibacter , and Winogradskyella developed well in the nutrient-enriched bottom water, while Reinekea and Thalassobius were favored by low-nutrient surface water. We revealed that the combination of 4°C, crude oil and bottom inoculum was a key factor for the growth of Cycloclasticus , while the combination of surface inoculum and bottom water chemistry was important for the growth of Pseudoalteromonas . Moreover, regardless of the source of inoculum, bottom water at 24°C was a favorable condition for Oleibacter. Redundancy analysis further showed that temperature and initial community explained 57 and 19% of the variation observed, while oil and water chemistry contributed 14 and 10%, respectively. Overall, this study revealed the relative roles of temperature, water

Formation of Chromophoric Dissolved Organic Matter by Bacterial Degradation of Phytoplankton-Derived Aggregates

Directory of Open Access Journals (Sweden)

Joanna D. Kinsey

2018-01-01

Full Text Available Organic matter produced and released by phytoplankton during growth is processed by heterotrophic bacterial communities that transform dissolved organic matter into biomass and recycle inorganic nutrients, fueling microbial food web interactions. Bacterial transformation of phytoplankton-derived organic matter also plays a poorly known role in the formation of chromophoric dissolved organic matter (CDOM which is ubiquitous in the ocean. Despite the importance of organic matter cycling, growth of phytoplankton and activities of heterotrophic bacterial communities are rarely measured in concert. To investigate CDOM formation mediated by microbial processing of phytoplankton-derived aggregates, we conducted growth experiments with non-axenic monocultures of three diatoms (Skeletonema grethae, Leptocylindrus hargravesii, Coscinodiscus sp. and one haptophyte (Phaeocystis globosa. Phytoplankton biomass, carbon concentrations, CDOM and base-extracted particulate organic matter (BEPOM fluorescence, along with bacterial abundance and hydrolytic enzyme activities (α-glucosidase, β-glucosidase, leucine-aminopeptidase were measured during exponential growth and stationary phase (~3–6 weeks and following 6 weeks of degradation. Incubations were performed in rotating glass bottles to keep cells suspended, promoting cell coagulation and, thus, formation of macroscopic aggregates (marine snow, more similar to surface ocean processes. Maximum carbon concentrations, enzyme activities, and BEPOM fluorescence occurred during stationary phase. Net DOC concentrations (0.19–0.46 mg C L−1 increased on the same order as open ocean concentrations. CDOM fluorescence was dominated by protein-like signals that increased throughout growth and degradation becoming increasingly humic-like, implying the production of more complex molecules from planktonic-precursors mediated by microbial processing. Our experimental results suggest that at least a portion of open

Natural Sunlight Shapes Crude Oil-Degrading Bacterial Communities in Northern Gulf of Mexico Surface Waters.

Science.gov (United States)

Bacosa, Hernando P; Liu, Zhanfei; Erdner, Deana L

2015-01-01

Following the Deepwater Horizon (DWH) spill in 2010, an enormous amount of oil was observed in the deep and surface waters of the northern Gulf of Mexico. Surface waters are characterized by intense sunlight and high temperature during summer. While the oil-degrading bacterial communities in the deep-sea plume have been widely investigated, the effect of natural sunlight on those in oil polluted surface waters remains unexplored to date. In this study, we incubated surface water from the DWH site with amendments of crude oil, Corexit dispersant, or both for 36 days under natural sunlight in the northern Gulf of Mexico. The bacterial community was analyzed over time for total abundance, density of alkane and polycyclic aromatic hydrocarbon degraders, and community composition via pyrosequencing. Our results showed that, for treatments with oil and/or Corexit, sunlight significantly reduced bacterial diversity and evenness and was a key driver of shifts in bacterial community structure. In samples containing oil or dispersant, sunlight greatly reduced abundance of the Cyanobacterium Synechococcus but increased the relative abundances of Alteromonas, Marinobacter, Labrenzia, Sandarakinotalea, Bartonella, and Halomonas. Dark samples with oil were represented by members of Thalassobius, Winogradskyella, Alcanivorax, Formosa, Pseudomonas, Eubacterium, Erythrobacter, Natronocella, and Coxiella. Both oil and Corexit inhibited the Candidatus Pelagibacter with or without sunlight exposure. For the first time, we demonstrated the effects of light in structuring microbial communities in water with oil and/or Corexit. Overall, our findings improve understanding of oil pollution in surface water, and provide unequivocal evidence that sunlight is a key factor in determining bacterial community composition and dynamics in oil polluted marine waters.

Predictable bacterial composition and hydrocarbon degradation in Arctic soils following diesel and nutrient disturbance.

Science.gov (United States)

Bell, Terrence H; Yergeau, Etienne; Maynard, Christine; Juck, David; Whyte, Lyle G; Greer, Charles W

2013-06-01

Increased exploration and exploitation of resources in the Arctic is leading to a higher risk of petroleum contamination. A number of Arctic microorganisms can use petroleum for growth-supporting carbon and energy, but traditional approaches for stimulating these microorganisms (for example, nutrient addition) have varied in effectiveness between sites. Consistent environmental controls on microbial community response to disturbance from petroleum contaminants and nutrient amendments across Arctic soils have not been identified, nor is it known whether specific taxa are universally associated with efficient bioremediation. In this study, we contaminated 18 Arctic soils with diesel and treated subsamples of each with monoammonium phosphate (MAP), which has successfully stimulated degradation in some contaminated Arctic soils. Bacterial community composition of uncontaminated, diesel-contaminated and diesel+MAP soils was assessed through multiplexed 16S (ribosomal RNA) rRNA gene sequencing on an Ion Torrent Personal Genome Machine, while hydrocarbon degradation was measured by gas chromatography analysis. Diversity of 16S rRNA gene sequences was reduced by diesel, and more so by the combination of diesel and MAP. Actinobacteria dominated uncontaminated soils with diesel degradation in MAP-treated soils, suggesting this may be an important group to stimulate. The predictability with which bacterial communities respond to these disturbances suggests that costly and time-consuming contaminated site assessments may not be necessary in the future.

Land-based salmon aquacultures change the quality and bacterial degradation of riverine dissolved organic matter

Science.gov (United States)

Kamjunke, Norbert; Nimptsch, Jorge; Harir, Mourad; Herzsprung, Peter; Schmitt-Kopplin, Philippe; Neu, Thomas R.; Graeber, Daniel; Osorio, Sebastian; Valenzuela, Jose; Carlos Reyes, Juan; Woelfl, Stefan; Hertkorn, Norbert

2017-03-01

Aquacultures are of great economic importance worldwide but pollute pristine headwater streams, lakes, and estuaries. However, there are no in-depth studies of the consequences of aquacultures on dissolved organic matter (DOM) composition and structure. We performed a detailed molecular level characterization of aquaculture DOM quality and its bacterial degradation using four salmon aquacultures in Chile. Fluorescence measurements, ultrahigh-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy of the DOM revealed specific and extensive molecular alterations caused by aquacultures. Aquacultures released large quantities of readily bioavailable metabolites (primarily carbohydrates and peptides/proteins, and lipids), causing the organic matter downstream of all the investigated aquacultures to deviate strongly from the highly processed, polydisperse and molecularly heterogeneous DOM found in pristine rivers. However, the upstream individual catchment DOM signatures remained distinguishable at the downstream sites. The benthic algal biovolume decreased and the bacterial biovolume and production increased downstream of the aquacultures, shifting stream ecosystems to a more heterotrophic state and thus impairing the ecosystem health. The bacterial DOM degradation rates explain the attenuation of aquaculture DOM within the subsequent stream reaches. This knowledge may aid the development of improved waste processing facilities and may help to define emission thresholds to protect sensitive stream ecosystems.

Characterization of Bacterial Hydrocarbon Degradation Potential in the Red Sea Through Metagenomic and Cultivation Methods

KAUST Repository

Bianchi, Patrick

2018-01-01

The focus of this thesis is on the characterization at the metagenomic level of the water column of the Red Sea and on the isolation and characterization of novel hydrocarbon-degrading species and genomes adapted to the unique environmental characteristics of the basin. The presence of metabolic genes responsible of both linear and aromatic hydrocarbon degradation has been evaluated from a metagenomic survey and a meta-analysis of already available datasets. In parallel, water column-based microcosms have been established with crude oil as the sole carbon source, with aim to isolate potential novel bacterial species and provide new genome-based insights on the hydrocarbon degradation potential available in the Red Sea.

High bacterial biodiversity increases degradation performance of hydrocarbons during bioremediation of contaminated harbor marine sediments

International Nuclear Information System (INIS)

Dell'Anno, Antonio; Beolchini, Francesca; Rocchetti, Laura; Luna, Gian Marco; Danovaro, Roberto

2012-01-01

We investigated changes of bacterial abundance and biodiversity during bioremediation experiments carried out on oxic and anoxic marine harbor sediments contaminated with hydrocarbons. Oxic sediments, supplied with inorganic nutrients, were incubated in aerobic conditions at 20 °C and 35 °C for 30 days, whereas anoxic sediments, amended with organic substrates, were incubated in anaerobic conditions at the same temperatures for 60 days. Results reported here indicate that temperature exerted the main effect on bacterial abundance, diversity and assemblage composition. At higher temperature bacterial diversity and evenness increased significantly in aerobic conditions, whilst decreased in anaerobic conditions. In both aerobic and anaerobic conditions, biodegradation efficiencies of hydrocarbons were significantly and positively related with bacterial richness and evenness. Overall results presented here suggest that bioremediation strategies, which can sustain high levels of bacterial diversity rather than the selection of specific taxa, may significantly increase the efficiency of hydrocarbon degradation in contaminated marine sediments. - Highlights: ► Bioremediation performance was investigated on hydrocarbon contaminated sediments. ► Major changes in bacterial diversity and assemblage composition were observed. ► Temperature exerted the major effect on bacterial assemblages. ► High bacterial diversity increased significantly biodegradation performance. ► This should be considered for sediment remediation by bio-treatments. - Bioremediation strategies which can sustain high levels of bacterial diversity may significantly increase the biodegradation of hydrocarbons in contaminated marine sediments.

Structure of hydrocarbonoclastic nitrate-reducing bacterial communities in bioturbated coastal marine sediments.

Science.gov (United States)

Stauffert, Magalie; Cravo-Laureau, Cristiana; Duran, Robert

2014-09-01

The organisation of denitrifying microorganisms in oil-polluted bioturbated sediments was investigated in mesocosms under conditions as closer as possible to that observed in the environment. Molecular and culture-dependent approaches revealed that denitrifying Gammaproteobacteria were abundant in oil-polluted and bioturbated sediments suggesting that they may play a key role in hydrocarbon degradation in the environment. T-RFLP and gene libraries analyses targeting nirS gene showed that denitrifying microbial communities structure was slightly affected by either the addition of Hediste diversicolor or crude oil revealing the metabolic versatility of denitrifying microorganisms. From oil-polluted sediments, distinct denitrifying hydrocarbonoclastic bacterial consortia were obtained by enrichment cultures on high molecular weight polyaromatic hydrocarbons (PAHs) (dibenzothiophene, fluoranthene, pyrene and chrysene) under nitrate-reducing conditions. Interestingly, molecular characterisation of the consortia showed that the denitrifying communities obtained from oiled microcosms with addition of H. diversicolor were different to that observed without H. diversicolor addition, especially with fluoranthene and chrysene revealing the bacterial diversity involved in the degradation of these PAHs. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Effect of exposure to sunlight and phosphorus-limitation on bacterial degradation of coloured dissolved organic matter (CDOM) in freshwater.

Science.gov (United States)

Kragh, Theis; Søndergaard, Morten; Tranvik, Lars

2008-05-01

This study reports on the interacting effect of photochemical conditioning of dissolved organic matter and inorganic phosphorus on the metabolic activity of bacteria in freshwater. Batch cultures with lake-water bacteria and dissolved organic carbon (DOC) extracted from a humic boreal river were arranged in an experimental matrix of three levels of exposure to simulated sunlight and three levels of phosphorus concentration. We measured an increase in bacterial biomass, a decrease in DOC and bacterial respiration as CO(2) production and O(2) consumption over 450 h. These measurements were used to calculate bacterial growth efficiency (BGE). Bacterial degradation of DOC increased with increasing exposure to simulated sunlight and availability of phosphorus and no detectable growth occurred on DOC that was not pre-exposed to simulated sunlight. The outcome of photochemical degradation of DOC changed with increasing availability of phosphorus, resulting in an increase in BGE from about 5% to 30%. Thus, the availability of phosphorus has major implications for the quantitative transfer of carbon in microbial food webs.

Use of biolog methodology for optimizing the degradation of hydrocarbons by bacterial consortia.

Science.gov (United States)

Ambrosoli, R; Bardi, L; Minati, J L; Belviso, S; Ricci, R; Marzona, M

2003-01-01

Biolog methodology was used for the preliminary screening of different cultural conditions in order to detect the best combination/s of factors influencing the metabolic performance of bacterial consortia active in the degradation of hydrocarbons. Two microbial consortia were tested for their activity on 2 hydrocarbons (nonadecane and eicosane) in presence of the following cultural coadjuvants: vegetal oil, beta-cyclodextrine, sodium acetate, mineral solution. Tests were conducted in Biolog MT plates, where only the redox indicator of microbial growth (tetrazolium violet) and no carbon sources are provided. The microwells were filled with various combinations of hydrocarbons, microbial inoculum and coadjuvants. Blanks were prepared with the same combinations but without hydrocarbons. The results obtained show the suitability of the methodology developed to identify the most active consortium and the conditions for its best degradation performance. The efficacy of Biolog methodology (Biolog Inc., USA) for the characterization of microbial communities on the basis of the metabolic profiles obtained on specific carbon sources in the microwells of Elisa-type plates, is widely acknowledged (Garland, 1997; Pietikäinen et al., 2000; Dauber and Wolters, 2000). Due to its aptitude to simultaneously evaluate multiple microbial responses and directly organize the results, it can be adapted to meet specific study purposes (Gamo and Shji, 1999). In the present research Biolog methodology was fitted for the preliminary screening of different cultural conditions, in order to detect the best combination/s of factors influencing the metabolic performance of bacterial consortia active in the degradation of aliphatic hydrocarbons, in view of their utilization for the bioremediation of polluted sites.

A new boronic acid fluorescent sensor based on fluorene for monosaccharides at physiological pH.

Science.gov (United States)

Hosseinzadeh, Rahman; Mohadjerani, Maryam; Pooryousef, Mona; Eslami, Abbas; Emami, Saeed

2015-06-05

Fluorescent boronic acids are very useful fluorescent sensor for detection of biologically important saccharides. Herein we synthesized a new fluorene-based fluorescent boronic acid that shows significant fluorescence changes upon addition of saccharides at physiological pH. Upon addition of fructose, sorbitol, glucose, galactose, ribose, and maltose at different concentration to the solution of 7-(dimethylamino)-9,9-dimethyl-9H-fluoren-2-yl-2-boronic acid (7-DMAFBA, 1), significant decreases in fluorescent intensity were observed. It was found that this boronic acid has high affinity (K(a)=3582.88 M(-1)) and selectivity for fructose over glucose at pH=7.4. The sensor 1 showed a linear response toward d-fructose in the concentrations ranging from 2.5×10(-5) to 4×10(-4) mol L(-1) with the detection limit of 1.3×10(-5) mol L(-1). Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of catchment land use and soil type on the concentration, quality, and bacterial degradation of riverine dissolved organic matter

DEFF Research Database (Denmark)

Autio, Iida; Soinne, Helena; Helin, Janne

2016-01-01

We studied the effects of catchment characteristics (soil type and land use) on the concentration and quality of dissolved organic matter (DOM) in river water and on the bacterial degradation of terrestrial DOM. The share of organic soil was the strongest predictor of high concentrations...... of dissolved organic carbon, nitrogen, and phosphorus (DOC, DON, and DOP, respectively), and was linked to DOM quality. Soil type was more important than land use in determining the concentration and quality of riverine DOM. On average, 5–9 % of the DOC and 45 % of the DON were degraded by the bacterial...

Luminescent Fluorene-Based Bis-Pyrazolyl Aniline Ligand for Aluminum Detection.

Science.gov (United States)

Frazer, Andrew; Morales, Alma R; Woodward, Adam W; Tongwa, Paul; Timofeeva, Tatiana; Belfield, Kevin D

2013-09-29

The design, synthesis, and photophysical properties of a new fluorene-based fluorescent chemosensor, 4-((E)-2-(2-(benzo[d]thiazol-2-yl)-9,9-diethyl-9H-fluoren-7-yl)vinyl)-N,N-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)benzenamine (AXF-Al), is described for the detection of Al 3+ . AXF-Al exhibited absorption at 382 nm and strong fluorescence emission at 542 nm (fluorescence quantum yield, Φ F , of 0.80). The capture of Al 3+ by the pyrazolyl aniline receptor resulted in nominal change in the linear absorption (372 nm) but a large hypsochromic shift of 161 nm in the fluorescence spectrum (542 to 433 nm, Φ F  = 0.88), from which Al 3+ was detected both ratiometrically and colorimetrically. The addition of other metal ions, namely Mg 2+ , Ca 2+ , Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , Cd 2+ , Hg 2+ and Pb 2+ , produced only minimal changes in the optical properties of this probe. The emission band of this probe was also accessed by two-photon excitation in the near-IR, as two-photon absorption (2PA) is important for potential applications in two-photon fluorescence microscopy (2PFM) imaging. The 2PA cross section of the free fluorenyl ligand AXF-Al was 220 GM at 810 nm and 235 GM at 810 nm for the Al-ligand complex, practically useful properties for 2PFM.

In-vitro Degradation Behaviour of Irradiated Bacterial Cellulose Membrane

International Nuclear Information System (INIS)

Darwis, D.; Khusniya, T.; Hardiningsih, L.; Nurlidar, F.; Winarno, H.

2012-01-01

Bacterial cellulose membrane synthesized by Acetobacter xylinum in coconut water medium has potential application for Guided bone Regeneration. However, this membrane may not meet some application requirements due to its low biodegradation properties. In this paper, incorporation of gamma irradiation into the membrane is a developed strategy to increase its biodegradability properties. The in-vitro degradation study in synthetic body fluid (SBF) of the irradiated membrane has been analyzed during periods of 6 months by means of weight loss, mechanical properties and scanning electron microscopy observation compared to that the un-irradiated one. The result showed that weight loss of irradiated membrane with 25 kGy and 50 kGy and immersed in SBF solution for 6 months reached 18% and 25% respectively. While un-irradiated membrane did not give significant weight loss. Tensile strength of membranes decreases with increasing of irradiation dose and further decreases in tensile strength is observed when irradiated membrane was followed by immersion in SBF solution. Microscope electron image of cellulose membranes shows that un-irradiated bacterial cellulose membrane consists of dense ultrafine fibril network structures, while irradiation result in cleavage of fibrils network of cellulose. The fibrils network become loosely after irradiated membrane immersed in SBF solution due to released of small molecular weight carbohydrates formed during by irradiation from the structure (author)

Enzymatic degradation of aliphatic nitriles by Rhodococcus rhodochrous BX2, a versatile nitrile-degrading bacterium.

Science.gov (United States)

Fang, Shumei; An, Xuejiao; Liu, Hongyuan; Cheng, Yi; Hou, Ning; Feng, Lu; Huang, Xinning; Li, Chunyan

2015-06-01

Nitriles are common environmental pollutants, and their removal has attracted increasing attention. Microbial degradation is considered to be the most acceptable method for removal. In this work, we investigated the biodegradation of three aliphatic nitriles (acetonitrile, acrylonitrile and crotononitrile) by Rhodococcus rhodochrous BX2 and the expression of their corresponding metabolic enzymes. This organism can utilize all three aliphatic nitriles as sole carbon and nitrogen sources, resulting in the complete degradation of these compounds. The degradation kinetics were described using a first-order model. The degradation efficiency was ranked according to t1/2 as follows: acetonitrile>trans-crotononitrile>acrylonitrile>cis-crotononitrile. Only ammonia accumulated following the three nitriles degradation, while amides and carboxylic acids were transient and disappeared by the end of the assay. mRNA expression and enzyme activity indicated that the tested aliphatic nitriles were degraded via both the inducible NHase/amidase and the constitutive nitrilase pathways, with the former most likely preferred. Copyright © 2015 Elsevier Ltd. All rights reserved.

Plant-associated bacterial degradation of toxic organic compounds in soil.

LENUS (Irish Health Repository)

McGuinness, Martina

2009-08-01

A number of toxic synthetic organic compounds can contaminate environmental soil through either local (e.g., industrial) or diffuse (e.g., agricultural) contamination. Increased levels of these toxic organic compounds in the environment have been associated with human health risks including cancer. Plant-associated bacteria, such as endophytic bacteria (non-pathogenic bacteria that occur naturally in plants) and rhizospheric bacteria (bacteria that live on and near the roots of plants), have been shown to contribute to biodegradation of toxic organic compounds in contaminated soil and could have potential for improving phytoremediation. Endophytic and rhizospheric bacterial degradation of toxic organic compounds (either naturally occurring or genetically enhanced) in contaminated soil in the environment could have positive implications for human health worldwide and is the subject of this review.

Metagenomic data of free cyanide and thiocyanate degrading bacterial communities

Directory of Open Access Journals (Sweden)

Lukhanyo Mekuto

2017-08-01

Full Text Available The data presented in this article contains the bacterial community structure of the free cyanide (CN- and thiocyanate (SCN- degrading organisms that were isolated from electroplating wastewater and synthetic SCN- containing wastewater. PCR amplification of the 16S rRNA V1-V3 regions was undertaken using the 27F and 518R oligonucleotide primers following the metacommunity DNA extraction procedure. The PCR amplicons were processed using the illumina® reaction kits as per manufacturer׳s instruction and sequenced using the illumina® MiSeq-2000, using the MiSeq V3 kit. The data was processed using bioinformatics tools such as QIIME and the raw sequence files are available via NCBI׳s Sequence Read Archive (SRA database.

Bacterial degradation of styrene in waste gases using a peat filter

Energy Technology Data Exchange (ETDEWEB)

Arnold, M.; Reittu, A. [Kuopio Univ. (Finland). Dept. of Environmental Sciences; Wright, A. von; Suihko, M.L. [VTT Biotechnology and Food Research (Finland); Martikainen, P.J. [Kuopio Univ. (Finland). Dept. of Environmental Sciences]|[National Public Health Inst., Lab. of Environmental Microbiology, Kuopio (Finland)

1997-12-31

A biofiltration process was developed for styrene-containing off-gases using peat as filter material. The average styrene reduction ratio after 190 days of operation was 70% (max. 98%) and the mean styrene elimination capacity was 12 g m{sup -3} h{sup -1} (max. 30 g m{sup -3} h{sup -1}). Efficient styrene degradation required addition of nutrients to the peat, adjustment of the pH to a neutral level and efficient control of the humidity. Maintenance of the water balance was easier in a down-flow than in an up-flow process, the former consequently resulting in much better filtration efficiency. The optimum operation temperature was around 23 C, but the styrene removal was still satisfactory at 12 C. Seven different bacterial isolates belonging to the genera Tsukamurella, Pseudomonas, Sphingomonas, Xanthomonas and an unidentified genus in the {gamma} group of the Proteobacteria isolated from the microflora of active peat filter material were capable of styrene degradation. The isolates differed in their capacity to decompose styrene to carbon dioxide and assimilate it to biomass. No toxic intermediate degradation products of styrene were detected in the filter outlet gas or in growing cultures of isolated bacteria. The use of these isolates in industrial biofilters is beneficial at low styrene concentrations and is safe from both the environmental and public health points of view. (orig.)

Bacterial degradation of styrene in waste gases using a peat filter.

Science.gov (United States)

Arnold, M; Reittu, A; von Wright, A; Martikainen, P J; Suihko, M L

1997-12-01

A biofiltration process was developed for styrene-containing off-gases using peat as filter material. The average styrene reduction ratio after 190 days of operation was 70% (max. 98%) and the mean styrene elimination capacity was 12 g m-3 h-1 (max. 30 g m-3 h-1). Efficient styrene degradation required addition of nutrients to the peat, adjustment of the pH to a neutral level and efficient control of the humidity. Maintenance of the water balance was easier in a down-flow than in an up-flow process, the former consequently resulting in much better filtration efficiency. The optimum operation temperature was around 23 degrees C, but the styrene removal was still satisfactory at 12 degrees C. Seven different bacterial isolates belonging to the genera Tsukamurella, Pseudomonas, Sphingomonas, Xanthomonas and an unidentified genus in the gamma group of the Proteobacteria isolated from the microflora of active peat filter material were capable of styrene degradation. The isolates differed in their capacity to decompose styrene to carbon dioxide and assimilate it to biomass. No toxic intermediate degradation products of styrene were detected in the filter outlet gas or in growing cultures of isolated bacteria. The use of these isolates in industrial biofilters is beneficial at low styrene concentrations and is safe from both the environmental and public health points of view.

Effects of the antibiotic ciprofloxacin on the bacterial community structure and degradation of pyrene in marine sediment

International Nuclear Information System (INIS)

Naeslund, Johan; Hedman, Jenny E.; Agestrand, Cecilia

2008-01-01

The ecological consequences of antibiotics in the aquatic environment have been an issue of concern over the past years due to the potential risk for negative effects on indigenous microorganisms. Microorganisms provide important ecosystem services, such as nutrient recycling, organic matter mineralization and degradation of pollutants. In this study, effects of exposure to the antibiotic ciprofloxacin on the bacterial diversity and pollutant degradation in natural marine sediments were studied using molecular methods (T-RFLP) in combination with radiorespirometry. In a microcosm experiment, sediment spiked with 14 C-labelled pyrene was exposed to five concentrations of ciprofloxacin (0, 20, 200, 1000 and 2000 μg L -1 ) in a single dose to the overlying water. The production of 14 CO 2 (i.e. complete mineralization of pyrene) was measured during 11 weeks. Sediment samples for bacterial community structure analysis were taken after 7 weeks. Results showed a significant dose-dependent inhibition of pyrene mineralization measured as the total 14 CO 2 production. The nominal EC 50 was calculated to 560 μg L -1 , corresponding to 0.4 μg/kg d.w. sediment. The lowest effect concentration on the bacterial community structure was 200 μg L -1 , which corresponds to 0.1 μg/kg d.w. sediment. Our results show that antibiotic pollution can be a potential threat to both bacterial diversity and an essential ecosystem service they perform in marine sediment

Enrichment and molecular characterization of a bacterial culture that degrades methoxy-methyl urea herbicides and their aniline derivatives.

Science.gov (United States)

El-Fantroussi, S; Verstraete, W; Top, E M

2000-12-01

Soil treated with linuron for more than 10 years showed high biodegradation activity towards methoxy-methyl urea herbicides. Untreated control soil samples taken from the same location did not express any linuron degradation activity, even after 40 days of incubation. Hence, the occurrence in the field of a microbiota having the capacity to degrade a specific herbicide was related to the long-term treatment of the soil. The enrichment culture isolated from treated soil showed specific degradation activity towards methoxy-methyl urea herbicides, such as linuron and metobromuron, while dimethyl urea herbicides, such as diuron, chlorotoluron, and isoproturon, were not transformed. The putative metabolic intermediates of linuron and metobromuron, the aniline derivatives 3, 4-dichloroaniline and 4-bromoaniline, were also degraded. The temperature of incubation drastically affected degradation of the aniline derivatives. Whereas linuron was transformed at 28 and 37 degrees C, 3,4-dichloroaniline was transformed only at 28 degrees C. Monitoring the enrichment process by reverse transcription-PCR and denaturing gradient gel electrophoresis (DGGE) showed that a mixture of bacterial species under adequate physiological conditions was required to completely transform linuron. This research indicates that for biodegradation of linuron, several years of adaptation have led to selection of a bacterial consortium capable of completely transforming linuron. Moreover, several of the putative species appear to be difficult to culture since they were detectable by DGGE but were not culturable on agar plates.

Isolation and characterization of novel hydrocarbon-degrading euryhaline consortia from crude oil and mangrove sediments.

Science.gov (United States)

Piedad Díaz, M; Grigson, S J; Peppiatt, C J; Burgess, J G

2000-11-01

Two novel and versatile bacterial consortia were developed for the biodegradation of hydrocarbons. They were isolated from crude oil from the Cormorant Field in the North Sea (MPD-7) and from sediment associated with mangrove roots (MPD-M). The bacterial consortia were able to degrade both aliphatic and aromatic hydrocarbons in crude oils very effectively in seawater (35 g/L NaCl) and synthetic media containing 0 to 100 g/L NaCl (1.7 M). Salinities over twice that of normal seawater decreased the biodegradation rates. However, even at the highest salinity biodegradation was significant. Ratios of nC17 to pristane and nC18 to phytane were significantly lowered across the range of salinity. The lowest values were at 0 and 20 g/L (0.34 M). Phytane was degraded in preference to pristane. The degradation of these compounds was constant over the salinity range, with evidence of a slight increase for consortium MPD-M with increasing salinity. In general, the consortium isolated from mangrove root sediments was more efficient in metabolizing North Sea crude oil than the consortium isolated from Cormorant crude oil. The 5 strains that comprise MPD-M have been tentatively identified as species of the genera Marinobacter, Bacillus, and Erwinia. This is the first report of hydrocarbon-degrading consortia isolated from crude oil and mangrove sediments that are capable of treating oily wastes over such a wide range of salinity.

The Role of the Bacterial Community of an Agroecosystem in Simazine Degradation

Directory of Open Access Journals (Sweden)

Roberto Ciccoli

2011-02-01

Full Text Available The use of pesticides and fertilizers in agricultural practice is the main source of soil and groundwater contamination. S-Triazines are among the most used herbicides in the world for selective weed control in several types of crops. The homeostatic capability of an agroecosystem to remove a triazinic herbicide, simazine, was assessed in microcosms treated with the herbicide in presence/absence of urea fertilizer. The latter, as well as a fertilizer, is also one of the last by-products before simazine mineralization. The biodegradation, in terms of disappearance of 50% of the initial concentration (DT50, was compared to the degradation and metabolite formation occurring in sterilized soil. Moreover, the bacterial community response was assessed in terms of abundance and community structure by the epifluorescence direct count method and fluorescence in situ hybridization. The results show that the microbial community has a primary role in simazine degradation and that this process is due to the presence of a microbial pool working in succession and of which the metabolism may be modulated by exogenous sources of nitrogen, like urea. The latter influences the degradative pathway with a greater formation and accumulation of the desethyl-simazine metabolite, which is a hazardous contaminant of soil and groundwater ecosystems, as well as its parent compound.

The Role of the Bacterial Community of an Agroecosystem in Simazine Degradation

Directory of Open Access Journals (Sweden)

Anna Barra Caracciolo

Full Text Available The use of pesticides and fertilizers in agricultural practice is the main source of soil and groundwater contamination. S-Triazines are among the most used herbicides in the world for selective weed control in several types of crops. The homeostatic capability of an agroecosystem to remove a triazinic herbicide, simazine, was assessed in microcosms treated with the herbicide in presence/absence of urea fertilizer. The latter, as well as a fertilizer, is also one of the last by-products before simazine mineralization. The biodegradation, in terms of disappearance of 50% of the initial concentration (DT50, was compared to the degradation and metabolite formation occurring in sterilized soil. Moreover, the bacterial community response was assessed in terms of abundance and community structure by the epifluorescence direct count method and fluorescence in situ hybridization. The results show that the microbial community has a primary role in simazine degradation and that this process is due to the presence of a microbial pool working in succession and of which the metabolism may be modulated by exogenous sources of nitrogen, like urea. The latter influences the degradative pathway with a greater formation and accumulation of the desethyl-simazine metabolite, which is a hazardous contaminant of soil and groundwater ecosystems, as well as its parent compound.

Detection of carboxylesterase and esterase activity in culturable gut bacterial flora isolated from diamondback moth, Plutella xylostella (Linnaeus, from India and its possible role in indoxacarb degradation

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Shanivarsanthe Leelesh Ramya

2016-06-01

Full Text Available Abstract Diamondback moth (DBM, Plutella xylostella (Linnaeus, is a notorious pest of brassica crops worldwide and is resistant to all groups of insecticides. The insect system harbors diverse groups of microbiota, which in turn helps in enzymatic degradation of xenobiotic-like insecticides. The present study aimed to determine the diversity of gut microflora in DBM, quantify esterase activity and elucidate their possible role in degradation of indoxacarb. We screened 11 geographic populations of DBM in India and analyzed them for bacterial diversity. The culturable gut bacterial flora underwent molecular characterization with 16S rRNA. We obtained 25 bacterial isolates from larvae (n = 13 and adults (n = 12 of DBM. In larval gut isolates, gammaproteobacteria was the most abundant (76%, followed by bacilli (15.4%. Molecular characterization placed adult gut bacterial strains into three major classes based on abundance: gammaproteobacteria (66%, bacilli (16.7% and flavobacteria (16.7%. Esterase activity from 19 gut bacterial isolates ranged from 0.072 to 2.32 µmol/min/mg protein. Esterase bands were observed in 15 bacterial strains and the banding pattern differed in Bacillus cereus – KC985225 and Pantoea agglomerans – KC985229. The bands were characterized as carboxylesterase with profenofos used as an inhibitor. Minimal media study showed that B. cereus degraded indoxacarb up to 20%, so it could use indoxacarb for metabolism and growth. Furthermore, esterase activity was greater with minimal media than control media: 1.87 versus 0.26 µmol/min/mg protein. Apart from the insect esterases, bacterial carboxylesterase may aid in the degradation of insecticides in DBM.

Hydrocarbon degradation potential in reference soils and soils contaminated with jet fuel

International Nuclear Information System (INIS)

Lee, R.F.; Hoeppel, R.

1991-01-01

Petroleum degradation in surface and subsurface soils is affected by such factors as moisture content, pH, soil type, soil organics, temperature, and oxygen concentrations. In this paper, the authors determine the degradation rates of 14 C-labeled hydrocarbons added to soils collected from a contaminated surface site, contaminated subsurface sites, and a clean reference site. The radiolabeled hydrocarbons used include benzene, toluene, naphthalene, 1-methynaphthalene, phenanthrene, fluorene, anthracene, chrysene, and hexadecane. Microbial degradation rates were based on determination of mineralization rates (production of 14 CO 2 ) of hydrocarbons that were added to soil samples. Since water was added and oxygen was not limiting, the hydrocarbon rates determined are likely to be higher than those occurring in situ. Using radiolabeled hydrocarbons, information can be provided on differences in the degradation rates of various petroleum compounds in different types of soils at a site, on possible production of petroleum metabolites in the soil, and on the importance of anaerobic petroleum degradation and the effects of nutrient, water, and surfactant addition on biodegradation rates

Bacterial community analysis of an industrial wastewater treatment plant in Colombia with screening for lipid-degrading microorganisms.

Science.gov (United States)

Silva-Bedoya, Lina Marcela; Sánchez-Pinzón, María Solange; Cadavid-Restrepo, Gloria Ester; Moreno-Herrera, Claudia Ximena

2016-11-01

The operation of wastewater treatment technologies depends on a combination of physical, chemical and biological factors. Microorganisms present in wastewater treatment plants play essential roles in the degradation and removal of organic waste and xenobiotic pollutants. Several microorganisms have been used in complementary treatments to process effluents rich in fats and oils. Microbial lipases have received significant industrial attention because of their stability, broad substrate specificity, high yields, and regular supply, as well as the fact that the microorganisms producing them grow rapidly on inexpensive media. In Colombia, bacterial community studies have focused on populations of cultivable nitrifying, heterotrophic and nitrogen-fixing bacteria present in constructed wetlands. In this study, culture-dependent methods, culture-independent methods (TTGE, RISA) and enzymatic methods were used to estimate bacterial diversity, to monitor temporal and spatial changes in bacterial communities, and to screen microorganisms that presented lipolytic activity. The dominant microorganisms in the Wastewater Treatment Plant (WWTP) examined in this study belonged to the phyla Firmicutes, Proteobacteria and Bacteroidetes. The enzymatic studies performed indicated that five bacterial isolates and three fungal isolates possessed the ability to degrade lipids; additionally, the Serratia, Kosakonia and Mucor genera presented lipase-mediated transesterification activity. The implications of these findings in regard to possible applications are discussed later in this paper. Our results indicate that there is a wide diversity of aerobic Gram-negative bacteria inhabiting the different sections of the WWTP, which could indicate its ecological condition, functioning and general efficiency. Copyright © 2016 Elsevier GmbH. All rights reserved.

Detection of carboxylesterase and esterase activity in culturable gut bacterial flora isolated from diamondback moth, Plutella xylostella (Linnaeus), from India and its possible role in indoxacarb degradation.

Science.gov (United States)

Ramya, Shanivarsanthe Leelesh; Venkatesan, Thiruvengadam; Srinivasa Murthy, Kottilingam; Jalali, Sushil Kumar; Verghese, Abraham

2016-01-01

Diamondback moth (DBM), Plutella xylostella (Linnaeus), is a notorious pest of brassica crops worldwide and is resistant to all groups of insecticides. The insect system harbors diverse groups of microbiota, which in turn helps in enzymatic degradation of xenobiotic-like insecticides. The present study aimed to determine the diversity of gut microflora in DBM, quantify esterase activity and elucidate their possible role in degradation of indoxacarb. We screened 11 geographic populations of DBM in India and analyzed them for bacterial diversity. The culturable gut bacterial flora underwent molecular characterization with 16S rRNA. We obtained 25 bacterial isolates from larvae (n=13) and adults (n=12) of DBM. In larval gut isolates, gammaproteobacteria was the most abundant (76%), followed by bacilli (15.4%). Molecular characterization placed adult gut bacterial strains into three major classes based on abundance: gammaproteobacteria (66%), bacilli (16.7%) and flavobacteria (16.7%). Esterase activity from 19 gut bacterial isolates ranged from 0.072 to 2.32μmol/min/mg protein. Esterase bands were observed in 15 bacterial strains and the banding pattern differed in Bacillus cereus - KC985225 and Pantoea agglomerans - KC985229. The bands were characterized as carboxylesterase with profenofos used as an inhibitor. Minimal media study showed that B. cereus degraded indoxacarb up to 20%, so it could use indoxacarb for metabolism and growth. Furthermore, esterase activity was greater with minimal media than control media: 1.87 versus 0.26μmol/min/mg protein. Apart from the insect esterases, bacterial carboxylesterase may aid in the degradation of insecticides in DBM. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Symmetry- and Solvent-Dependent Photophysics of Fluorenes Containing Donor and Acceptor Groups (Postprint)

Science.gov (United States)

2014-07-01

for exciplex forma- tion.29,30 Solvent-dependent studies by Belfield et al. on similar dyes31 and BT2F32 revealed strong solvatochromism on the emission...Swiger, R. N.; Orseno, D. L.; Haley, J. E.; Cooper, T. M.; Tan, L.-S. Exciplex Formation in Solid State Blends of Charge-Transfer-Type Afx Dyes and...Tan, L.-S. Exciplex Formation in Blended Spin-Cast Films of Fluorene-Linked Dyes and Bisphthalimide Quenchers. J. Phys. Chem. A 2013, 117, 3909−3917

Culture-dependent and culture-independent characterization of potentially functional biphenyl-degrading bacterial community in response to extracellular organic matter from Micrococcus luteus.

Science.gov (United States)

Su, Xiao-Mei; Liu, Yin-Dong; Hashmi, Muhammad Zaffar; Ding, Lin-Xian; Shen, Chao-Feng

2015-05-01

Biphenyl (BP)-degrading bacteria were identified to degrade various polychlorinated BP (PCB) congers in long-term PCB-contaminated sites. Exploring BP-degrading capability of potentially useful bacteria was performed for enhancing PCB bioremediation. In the present study, the bacterial composition of the PCB-contaminated sediment sample was first investigated. Then extracellular organic matter (EOM) from Micrococcus luteus was used to enhance BP biodegradation. The effect of the EOM on the composition of bacterial community was investigated by combining with culture-dependent and culture-independent methods. The obtained results indicate that Proteobacteria and Actinobacteria were predominant community in the PCB-contaminated sediment. EOM from M. luteus could stimulate the activity of some potentially difficult-to-culture BP degraders, which contribute to significant enhancement of BP biodegradation. The potentially difficult-to-culture bacteria in response to EOM addition were mainly Rhodococcus and Pseudomonas belonging to Gammaproteobacteria and Actinobacteria respectively. This study provides new insights into exploration of functional difficult-to-culture bacteria with EOM addition and points out broader BP/PCB degrading, which could be employed for enhancing PCB-bioremediation processes. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Characterization of Enzymatic Activity of MlrB and MlrC Proteins Involved in Bacterial Degradation of Cyanotoxins Microcystins.

Science.gov (United States)

Dziga, Dariusz; Zielinska, Gabriela; Wladyka, Benedykt; Bochenska, Oliwia; Maksylewicz, Anna; Strzalka, Wojciech; Meriluoto, Jussi

2016-03-16

Bacterial degradation of toxic microcystins produced by cyanobacteria is a common phenomenon. However, our understanding of the mechanisms of these processes is rudimentary. In this paper several novel discoveries regarding the action of the enzymes of the mlr cluster responsible for microcystin biodegradation are presented using recombinant proteins. In particular, the predicted active sites of the recombinant MlrB and MlrC were analyzed using functional enzymes and their inactive muteins. A new degradation intermediate, a hexapeptide derived from linearized microcystins by MlrC, was discovered. Furthermore, the involvement of MlrA and MlrB in further degradation of the hexapeptides was confirmed and a corrected biochemical pathway of microcystin biodegradation has been proposed.

Characterization of Enzymatic Activity of MlrB and MlrC Proteins Involved in Bacterial Degradation of Cyanotoxins Microcystins

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Dariusz Dziga

2016-03-01

Full Text Available Bacterial degradation of toxic microcystins produced by cyanobacteria is a common phenomenon. However, our understanding of the mechanisms of these processes is rudimentary. In this paper several novel discoveries regarding the action of the enzymes of the mlr cluster responsible for microcystin biodegradation are presented using recombinant proteins. In particular, the predicted active sites of the recombinant MlrB and MlrC were analyzed using functional enzymes and their inactive muteins. A new degradation intermediate, a hexapeptide derived from linearized microcystins by MlrC, was discovered. Furthermore, the involvement of MlrA and MlrB in further degradation of the hexapeptides was confirmed and a corrected biochemical pathway of microcystin biodegradation has been proposed.

Bacteria and lignin degradation

Institute of Scientific and Technical Information of China (English)

Jing LI; Hongli YUAN; Jinshui YANG

2009-01-01

Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

Bacterial diversity exploration in hydrocarbon polluted soil: metabolic potential and degrader community evolution revealed by isotope labeling

International Nuclear Information System (INIS)

Martin, F.

2011-01-01

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds produced by incomplete combustion of organic matter. They are a source of environmental pollution, especially associated to oil product exploitation, and represent a threat for living organisms including human beings because of their toxicity. Many bacteria capable of degrading PAHs have been isolated and studied. However, since less than 5% of soil bacteria can be cultivated in the laboratory, bacterial species able to degrade PAHs in situ have been poorly studied. The first goal of this study was to identify bacteria that degrade PAHs in soil using culture-independent molecular methods. To this end, a strategy known a stable isotope probing has been implemented based on the use of phenanthrene, a three rings PAH, in which the natural isotope of carbon was replaced by 13 C. This molecule has been introduced as a tracer in microcosms containing soil from a constructed wetlands collecting contaminated water from highway runoff. Bacteria having incorporated the 13 C were then identified by 16 S rRNA gene sequence analysis after PCR amplification from labeled genomic DNA extracted from soil. The results show that so far little studied Betaproteobacteria, belonging to the genera Acidovorax, Rhodoferax, Hydrogenophaga and Thiobacillus, as well as Rhodocyclaceae, were the key players in phenanthrene degradation. Predominance of Betaproteobacteries was established thanks to quantitative PCR measurements. A dynamic analysis of bacterial diversity also showed that the community structure of degraders depended on phenanthrene bioavailability. In addition, the phylogenetic diversity of ring-hydroxylating di-oxygenases, enzymes involved in the first step of PAH degradation, has been explored. We detected new sequences, mostly related to di-oxygenases from Sphingomonadales and Burkholderiales. For the first time, we were able to associate a catalytic activity for oxidation of PAHs to partial gene sequences

Molecular diversity analysis and bacterial population dynamics of an adapted seawater microbiota during the degradation of Tunisian zarzatine oil.

Science.gov (United States)

Zrafi-Nouira, Ines; Guermazi, Sonda; Chouari, Rakia; Safi, Nimer M D; Pelletier, Eric; Bakhrouf, Amina; Saidane-Mosbahi, Dalila; Sghir, Abdelghani

2009-07-01

The indigenous microbiota of polluted coastal seawater in Tunisia was enriched by increasing the concentration of zarzatine crude oil. The resulting adapted microbiota was incubated with zarzatine crude oil as the only carbon and energy source. Crude oil biodegradation capacity and bacterial population dynamics of the microbiota were evaluated every week for 28 days (day 7, day 14, day 21, and day 28). Results show that the percentage of petroleum degradation was 23.9, 32.1, 65.3, and 77.8%, respectively. At day 28, non-aromatic and aromatic hydrocarbon degradation rates reached 92.6 and 68.7%, respectively. Bacterial composition of the adapted microflora was analysed by 16S rRNA gene cloning and sequencing, using total genomic DNA extracted from the adapted microflora at days 0, 7, 14, 21, and 28. Five clone libraries were constructed and a total of 430 sequences were generated and grouped into OTUs using the ARB software package. Phylogenetic analysis of the adapted microbiota shows the presence of four phylogenetic groups: Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. Diversity indices show a clear decrease in bacterial diversity of the adapted microflora according to the incubation time. The Proteobacteria are the most predominant (>80%) at day 7, day 14 and day 21 but not at day 28 for which the microbiota was reduced to only one OTU affiliated with the genus Kocuria of the Actinobacteria. This study shows that the degradation of zarzatine crude oil components depends on the activity of a specialized and dynamic seawater consortium composed of different phylogenetic taxa depending on the substrate complexity.

Valence one-electron and shake-up ionization bands of fluorene, carbazole and dibenzofuran

International Nuclear Information System (INIS)

Reza Shojaei, S.H.; Morini, Filippo; Deleuze, Michael S.

2013-01-01

Highlights: • The photoelectron spectra of the title compounds are assigned in details. • Shake-up lines are found to severely contaminate both π- and σ-ionization bands. • σ-ionization onsets are subject to severe vibronic coupling complications. • We compare the results of OVGF, ADC(3) and TDDFT calculations. - Abstract: A comprehensive study of the He (I) ultra-violet photoelectron spectra of fluorene, carbazole and dibenzofuran is presented with the aid of one-particle Green’s Function calculations employing the outer-valence Green’s Function (OVGF) approach and the third-order algebraic diagrammatic construction [ADC(3)] scheme, along with Dunning’s correlation consistent basis sets of double and triple zeta quality (cc-pVDZ, cc-pVTZ). Extrapolations of the ADC(3) results for the outermost one-electron π-ionization energies to the cc-pVTZ basis set enable theoretical insights into He (I) measurements within ∼0.15 eV accuracy, up to the σ-ionization onset. The lower ionization energy of carbazole is the combined result of mesomeric and electronic relaxation effects. OVGF/cc-pVDZ or OVGF/cc-pVTZ pole strengths smaller than 0.85 systematically corroborate a breakdown of the orbital picture of ionization at the ADC(3) level. Comparison is made with calculations of the lowest doublet–doublet excitation energies of the radical cation of fluorene, by means of time-dependent density functional theory (TDDFT)

Molecular Characterization of the Bacterial Community in Biofilms for Degradation of Poly(3-Hydroxybutyrate-co-3-Hydroxyhexanoate) Films in Seawater.

Science.gov (United States)

Morohoshi, Tomohiro; Ogata, Kento; Okura, Tetsuo; Sato, Shunsuke

2018-03-29

Microplastics are fragmented pieces of plastic in marine environments, and have become a serious environmental issue. However, the dynamics of the biodegradation of plastic in marine environments have not yet been elucidated in detail. Polyhydroxyalkanoates (PHAs) are biodegradable polymers that are synthesized by a wide range of microorganisms. One of the PHA derivatives, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) has flexible material properties and a low melting temperature. After an incubation in seawater samples, a significant amount of biofilms were observed on the surfaces of PHBH films, and some PHBH films were mostly or partially degraded. In the biofilms that formed on the surfaces of unbroken PHBH films, the most dominant operational taxonomic units (OTUs) showed high similarity with the genus Glaciecola in the family Alteromonadaceae. On the other hand, the dominant OTUs in the biofilms that formed on the surfaces of broken PHBH films were assigned to the families Rhodobacteraceae, Rhodospirillaceae, and Oceanospirillaceae, and the genus Glaciecola mostly disappeared. The bacterial community in the biofilms on PHBH films was assumed to have dynamically changed according to the progression of degradation. Approximately 50 colonies were isolated from the biofilm samples that formed on the PHBH films and their PHBH-degrading activities were assessed. Two out of three PHBH-degrading isolates showed high similarities to Glaciecola lipolytica and Aestuariibacter halophilus in the family Alteromonadaceae. These results suggest that bacterial strains belonging to the family Alteromonadaceae function as the principal PHBH-degrading bacteria in these biofilms.

Bacterial Degradation of Pesticides

DEFF Research Database (Denmark)

Knudsen, Berith Elkær

could potentially improve bioremediation of BAM. An important prerequisite for bioaugmentation is the potential to produce the degrader strain at large quantities within reasonable time. The aim of manuscript II, was to optimize the growth medium for Aminobacter MSH1 and to elucidate optimal growth...

Enhancement of pyrene degradation efficacy of Synechocystis sp., by construction of an artificial microalgal-bacterial consortium

Directory of Open Access Journals (Sweden)

Jignasa G. Patel

2015-12-01

Full Text Available This study was carried out to investigate the ability of microalgae Synechocystis sp. to high molecular weight Polycyclic Aromatic Hydrocarbon pyrene (PYR and artificial microalgal–bacterial consortium at different concentrations. The consortium consisted of one axenic species Synechocystis sp. and two PYR-degrading bacteria with known complementary degradative capabilities viz. Pseudomonas sp. and Bacillus sp. The influence of PYR on growth in terms of chlorophyll-a were analysed, and it was found that in the presence of bacteria, Synechocystis sp. tremendously increased in growth as well as biodegradation capability, whereas Synechocystis sp. alone exhibited concentration-dependent decrease in growth and biodegradation ability. Degradation of PYR shows that the consortium could eliminate PYR by 94.1% at 50 mg/L; however, Synechocystis sp alone could degrade up to 36% at 1.5 mg/L after 16 days of incubation. The study revealed that microalgae grew better in the presence of the aerobic heterotrophic bacteria and provided them with necessary organics for efficient PYR degradation activities. Moreover, consortium JP-NKA7B2 grows efficiently on other xenobiotic compounds. The artificial consortia JP-NK is thus proven to be an effective and promising system for bioremediating PYR compound and could be suggested in degradation of PYR compound in hydrocarbon-polluted areas in situ and ex situ.

Characterization of the biodegradation, bioremediation and detoxification capacity of a bacterial consortium able to degrade the fungicide thiabendazole.

Science.gov (United States)

Perruchon, Chiara; Pantoleon, Anastasios; Veroutis, Dimitrios; Gallego-Blanco, Sara; Martin-Laurent, F; Liadaki, Kalliopi; Karpouzas, Dimitrios G

2017-12-01

Thiabendazole (TBZ) is a persistent fungicide used in the post-harvest treatment of fruits. Its application results in the production of contaminated effluents which should be treated before their environmental discharge. In the absence of efficient treatment methods in place, biological systems based on microbial inocula with specialized degrading capacities against TBZ could be a feasible treatment approach. Only recently the first bacterial consortium able to rapidly transform TBZ was isolated. This study aimed to characterize its biodegradation, bioremediation and detoxification potential. The capacity of the consortium to mineralize 14 C-benzyl-ring labelled TBZ was initially assessed. Subsequent tests evaluated its degradation capacity under various conditions (range of pH, temperatures and TBZ concentration levels) and relevant practical scenarios (simultaneous presence of other postharvest compounds) and its bioaugmentation potential in soils contaminated with increasing TBZ levels. Finally cytotoxicity assays explored its detoxification potential. The consortium effectively mineralized the benzoyl ring of the benzimidazole moiety of TBZ and degraded spillage level concentrations of the fungicide in aqueous cultures (750 mg L -1 ) and in soil (500 mg kg -1 ). It maintained its high degradation capacity in a wide range of pH (4.5-7.5) and temperatures (15-37 °C) and in the presence of other pesticides (ortho-phenylphenol and diphenylamine). Toxicity assays using the human liver cancer cell line HepG2 showed a progressive decrease in cytotoxicity, concomitantly with the biodegradation of TBZ, pointing to a detoxification process. Overall, the bacterial consortium showed high potential for future implementation in bioremediation and biodepuration applications.

Mass production of bacterial communities adapted to the degradation of volatile organic compounds (TEX).

Science.gov (United States)

Lapertot, Miléna; Seignez, Chantal; Ebrahimi, Sirous; Delorme, Sandrine; Peringer, Paul

2007-06-01

This study focuses on the mass cultivation of bacteria adapted to the degradation of a mixture composed of toluene, ethylbenzene, o-, m- and p-xylenes (TEX). For the cultivation process Substrate Pulse Batch (SPB) technique was adapted under well-automated conditions. The key parameters to be monitored were handled by LabVIEW software including, temperature, pH, dissolved oxygen and turbidity. Other parameters, such as biomass, ammonium or residual substrate concentrations needed offline measurements. SPB technique has been successfully tested experimentally on TEX. The overall behavior of the mixed bacterial population was observed and discussed along the cultivation process. Carbon and nitrogen limitations were shown to affect the integrity of the bacterial cells as well as their production of exopolymeric substances (EPS). Average productivity and yield values successfully reached the industrial specifications, which were 0.45 kg(DW)m(-3) d(-1) and 0.59 g(DW)g (C) (-1) , respectively. Accuracy and reproducibility of the obtained results present the controlled SPB process as a feasible technique.

Natural Sunlight Shapes Crude Oil-Degrading Bacterial Communities in Northern Gulf of Mexico Surface Waters

OpenAIRE

Bacosa, Hernando P.; Liu, Zhanfei; Erdner, Deana L.

2015-01-01

Following the Deepwater Horizon (DWH) spill in 2010, an enormous amount of oil was observed in the deep and surface waters of the northern Gulf of Mexico. Surface waters are characterized by intense sunlight and high temperature during summer. While the oil-degrading bacterial communities in the deep-sea plume have been widely investigated, the effect of natural sunlight on those in oil polluted surface waters remains unexplored to date. In this study, we incubated surface water from the DWH ...

Improvement of the Bacterial Pure Culture 3A by Gamma Irradiation for Increasing Efficiency in Degrading Pesticides

International Nuclear Information System (INIS)

Tongpim, Saowanit; Piadaeng, Nattaya

2006-09-01

This research work had an objective to improve bacterial activity in degrading a herbicide: 2,4-dichlorophenoxyacetic acid (2,4-D). The bacterial isolate 3 A , kept in the culture collection of Khon Kaen University that could degrade 2,4-D, was employed in this experiment. Cell suspension of isolate 3 A was exposed to gamma irradiation at various doses (1-5 kGy). The isolated survivors were screened on the basis of forming larger colonies than the parent strain 3 A when grown on mineral salts agar containing 2,4-D (MS + 2,4-D) as the sole carbon source. We obtained 70 effective isolates which 6 isolates called 3 A I2-21, 3 A I2-23, 3 A I1-51, 3 A I2-71, 3 A I1-52 and 3 A I2-73 were chosen for further studies. These 6 irradiated isolates together with the parent strain were characterized using morphological, physiological and biochemical tests. They were all identified as Pseudomonas cepacia. All isolates had optimal growth pH of 7 and grew best at 30 o C. Biodegradation experiments performed in mineral salts medium containing 200 ppm of 2,4-D showed that after 20 days of incubation 36.9%, 65.3%, 57.2%, 54.8%, 53.4%, 47.3% and 45.8% of 2,4- D was degraded by isolates 3 A , 3 A I2-21, 3 A I2-23, 3 A I1-51, 3 A I2-71, 3 A I1-52 and 3 A I2-73, respectively. Comparing the irradiated strains with parent strain 3 A revealed that the isolate 3 A I2-21 was the most effective one as it could degrade 2,4-D about 28.4% greater than the parent strain 3 A .

Degradation of Bacterial Quorum Sensing Signaling Molecules by the Microscopic Yeast Trichosporon loubieri Isolated from Tropical Wetland Waters

Directory of Open Access Journals (Sweden)

Cheng-Siang Wong

2013-09-01

Full Text Available Proteobacteria produce N-acylhomoserine lactones as signaling molecules, which will bind to their cognate receptor and activate quorum sensing-mediated phenotypes in a population-dependent manner. Although quorum sensing signaling molecules can be degraded by bacteria or fungi, there is no reported work on the degradation of such molecules by basidiomycetous yeast. By using a minimal growth medium containing N-3-oxohexanoylhomoserine lactone as the sole source of carbon, a wetland water sample from Malaysia was enriched for microbial strains that can degrade N-acylhomoserine lactones, and consequently, a basidiomycetous yeast strain WW1C was isolated. Morphological phenotype and molecular analyses confirmed that WW1C was a strain of Trichosporon loubieri. We showed that WW1C degraded AHLs with N-acyl side chains ranging from 4 to 10 carbons in length, with or without oxo group substitutions at the C3 position. Re-lactonisation bioassays revealed that WW1C degraded AHLs via a lactonase activity. To the best of our knowledge, this is the first report of degradation of N-acyl-homoserine lactones and utilization of N-3-oxohexanoylhomoserine as carbon and nitrogen source for growth by basidiomycetous yeast from tropical wetland water; and the degradation of bacterial quorum sensing molecules by an eukaryotic yeast.

Investigating bacterial populations in styrene-degrading biofilters by 16S rDNA tag pyrosequencing.

Science.gov (United States)

Portune, Kevin J; Pérez, M Carmen; Álvarez-Hornos, F Javier; Gabaldón, Carmen

2015-01-01

Microbial biofilms are essential components in the elimination of pollutants within biofilters, yet still little is known regarding the complex relationships between microbial community structure and biodegradation function within these engineered ecosystems. To further explore this relationship, 16S rDNA tag pyrosequencing was applied to samples taken at four time points from a styrene-degrading biofilter undergoing variable operating conditions. Changes in microbial structure were observed between different stages of biofilter operation, and the level of styrene concentration was revealed to be a critical factor affecting these changes. Bacterial genera Azoarcus and Pseudomonas were among the dominant classified genera in the biofilter. Canonical correspondence analysis (CCA) and correlation analysis revealed that the genera Brevundimonas, Hydrogenophaga, and Achromobacter may play important roles in styrene degradation under increasing styrene concentrations. No significant correlations (P > 0.05) could be detected between biofilter operational/functional parameters and biodiversity measurements, although biological heterogeneity within biofilms and/or technical variability within pyrosequencing may have considerably affected these results. Percentages of selected bacterial taxonomic groups detected by fluorescence in situ hybridization (FISH) were compared to results from pyrosequencing in order to assess the effectiveness and limitations of each method for identifying each microbial taxon. Comparison of results revealed discrepancies between the two methods in the detected percentages of numerous taxonomic groups. Biases and technical limitations of both FISH and pyrosequencing, such as the binding of FISH probes to non-target microbial groups and lack of classification of sequences for defined taxonomic groups from pyrosequencing, may partially explain some differences between the two methods.

Bioremediation of high molecular weight polyaromatic hydrocarbons co-contaminated with metals in liquid and soil slurries by metal tolerant PAHs degrading bacterial consortium.

Science.gov (United States)

Thavamani, Palanisami; Megharaj, Mallavarapu; Naidu, Ravi

2012-11-01

Bioremediation of polyaromatic hydrocarbons (PAH) contaminated soils in the presence of heavy metals have proved to be difficult and often challenging due to the ability of toxic metals to inhibit PAH degradation by bacteria. In this study, a mixed bacterial culture designated as consortium-5 was isolated from a former manufactured gas plant (MGP) site. The ability of this consortium to utilise HMW PAHs such as pyrene and BaP as a sole carbon source in the presence of toxic metal Cd was demonstrated. Furthermore, this consortium has proven to be effective in degradation of HMW PAHs even from the real long term contaminated MGP soil. Thus, the results of this study demonstrate the great potential of this consortium for field scale bioremediation of PAHs in long term mix contaminated soils such as MGP sites. To our knowledge this is the first study to isolate and characterize metal tolerant HMW PAH degrading bacterial consortium which shows great potential in bioremediation of mixed contaminated soils such as MGP.

A new selective fluorene-based fluorescent internal charge transfer (ICT) sensor for sugar alcohols in aqueous solution.

Science.gov (United States)

Hosseinzadeh, Rahman; Mohadjerani, Maryam; Pooryousef, Mona

2016-03-01

Sugar alcohols, such as sorbitol, are commonly used as a replacement for sucrose in the food industry, applied as starting material for vitamin C synthesis, and involved as one of the causative factors in diabetic complications. Therefore, their detection and quantification in aqueous solution are necessary. The reversible covalent interactions between boronic acids and diols are the basis of efficient methods for the detection of saccharides. Herein, we report a new internal charge transfer (ICT) fluorene-based fluorescent boronic acid sensor (1) 2-[(9,9-dimethyl-9H-fluoren-2-yl-amino)methyl] phenyl boronic acid that shows significant fluorescence changes upon addition of saccharides. The boronic acid has high affinity (K a = 1107.9 M(-1)) and selectivity for sorbitol at pH = 8.31. It showed a linear response toward sorbitol in the concentration range from 1.0 × 10(-5) to 6.0 × 10(-4) mol L(-1) with the detection limit of 7.04 × 10(-6) mol L(-1). Sensor 1 was used to detect sorbitol in real samples with good recovery.

Comparison of Paraffin and Diesel Oil as Cultivation Medium Supplements for Preparing a Hydrocarbon-Degrading Bacterial Biomass

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Dokukins Eduards

2016-05-01

Full Text Available The effect of liquid paraffin and diesel oil as nutrient amendments for hydrocarbon-degrading bacteria was compared. Different parameters were analyzed - optical density of bacterial suspension, oxygen consumption by biomass, morphology of bacteria, etc. In some experiments the paraffin was more preferable for microorganisms, but in other tests the results for both substances were similar. The influence of the comparable substances strongly depends on cultivation conditions.

Characterization of Bacterial Hydrocarbon Degradation Potential in the Red Sea Through Metagenomic and Cultivation Methods

KAUST Repository

Bianchi, Patrick

2018-02-01

Prokaryotes are the main actors in biogeochemical cycles that are fundamental in global nutrient cycling. The characterization of microbial communities and isolates can enhance the comprehension of such cycles. Potentially novel biochemical processes can be discovered in particular environments with unique characteristics. The Red Sea can be considered as a unique natural laboratory due to its peculiar hydrology and physical features including temperature, salinity and water circulation. Moreover the Red Sea is subjected to hydrocarbon pollution by both anthropogenic and natural sources that select hydrocarbon degrading prokaryotes. Due to its unique features the Red Sea has the potential to host uncharacterized novel microorganisms with hydrocarbondegrading pathways. The focus of this thesis is on the characterization at the metagenomic level of the water column of the Red Sea and on the isolation and characterization of novel hydrocarbon-degrading species and genomes adapted to the unique environmental characteristics of the basin. The presence of metabolic genes responsible of both linear and aromatic hydrocarbon degradation has been evaluated from a metagenomic survey and a meta-analysis of already available datasets. In parallel, water column-based microcosms have been established with crude oil as the sole carbon source, with aim to isolate potential novel bacterial species and provide new genome-based insights on the hydrocarbon degradation potential available in the Red Sea.

Degradation pathways of 1-methylphenanthrene in bacterial Sphingobium sp. MP9-4 isolated from petroleum-contaminated soil.

Science.gov (United States)

Zhong, Jianan; Luo, Lijuan; Chen, Baowei; Sha, Sha; Qing, Qing; Tam, Nora F Y; Zhang, Yong; Luan, Tiangang

2017-01-30

Alkylated polycyclic aromatic hydrocarbons (PAHs) are abundant in petroleum, and alkylated phenanthrenes are considered as the primary PAHs during some oil spill events. Bacterial strain of Sphingobium sp. MP9-4, isolated from petroleum-contaminated soil, was efficient to degrade 1-methylphenanthrene (1-MP). A detailed metabolism map of 1-MP in this strain was delineated based on analysis of metabolites with gas chromatograph-mass spectrometer (GC-MS). 1-MP was initially oxidized via two different biochemical strategies, including benzene ring and methyl-group attacks. Benzene ring attack was initiated with dioxygenation of the non-methylated aromatic ring via similar degradation pathways of phenanthrene (PHE) by bacteria. For methyl-group attack, mono oxygenase system was involved and more diverse enzymes were needed than that of PHE degradation. This study enhances the understanding of the metabolic pathways of alkylated PAHs and shows the significant potential of Sphingobium sp. MP9-4 for the bioremediation of alkylated PAHs contaminated environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dynamics of indigenous bacterial communities associated with crude oil degradation in soil microcosms during nutrient-enhanced bioremediation.

Science.gov (United States)

Chikere, Chioma B; Surridge, Karen; Okpokwasili, Gideon C; Cloete, Thomas E

2012-03-01

present study therefore demonstrated that the soil investigated harbours hydrocarbon-degrading bacterial populations which can be biostimulated to achieve effective bioremediation of oil-contaminated soil.

Bacterial community dynamics during start-up of a trickle-bed bioreactor degrading aromatic compounds.

Science.gov (United States)

Stoffels, M; Amann, R; Ludwig, W; Hekmat, D; Schleifer, K H

1998-03-01

This study was performed with a laboratory-scale fixed-bed bioreactor degrading a mixture of aromatic compounds (Solvesso100). The starter culture for the bioreactor was prepared in a fermentor with a wastewater sample of a care painting facility as the inoculum and Solvesso100 as the sole carbon source. The bacterial community dynamics in the fermentor and the bioreactor were examined by a conventional isolation procedure and in situ hybridization with fluorescently labeled rRNA-targeted oligonucleotides. Two significant shifts in the bacterial community structure could be demonstrated. The original inoculum from the wastewater of the car factory was rich in proteobacteria of the alpha and beta subclasses, while the final fermentor enrichment was dominated by bacteria closely related to Pseudomonas putida or Pseudomonas mendocina, which both belong to the gamma subclass of the class Proteobacteria. A second significant shift was observed when the fermentor culture was transferred as inoculum to the trickle-bed bioreactor. The community structure in the bioreactor gradually returned to a higher complexity, with the dominance of beta and alpha subclass proteobacteria, whereas the gamma subclass proteobacteria sharply declined. Obviously, the preceded pollutant adaptant did not lead to a significant enrichment of bacteria that finally dominated in the trickle-bed bioreactor. In the course of experiments, three new 16S as well as 23S rRNA-targeted probes for beta subclass proteobacteria were designed, probe SUBU1237 for the genera Burkholderia and Sutterella, probe ALBO34a for the genera Alcaligenes and Bordetella, and probe Bcv13b for Burkholderia cepacia and Burkholderia vietnamiensis. Bacteria hybridizing with the probe Bcv13b represented the main Solvesso100-degrading population in the reactor.

Dispersal networks for enhancing bacterial degradation in heterogeneous environments

International Nuclear Information System (INIS)

Banitz, Thomas; Wick, Lukas Y.; Fetzer, Ingo; Frank, Karin; Harms, Hauke; Johst, Karin

2011-01-01

Successful biodegradation of organic soil pollutants depends on their bioavailability to catabolically active microorganisms. In particular, environmental heterogeneities often limit bacterial access to pollutants. Experimental and modelling studies revealed that fungal networks can facilitate bacterial dispersal and may thereby improve pollutant bioavailability. Here, we investigate the influence of such bacterial dispersal networks on biodegradation performance under spatially heterogeneous abiotic conditions using a process-based simulation model. To match typical situations in polluted soils, two types of abiotic conditions are studied: heterogeneous bacterial dispersal conditions and heterogeneous initial resource distributions. The model predicts that networks facilitating bacterial dispersal can enhance biodegradation performance for a wide range of these conditions. Additionally, the time horizon over which this performance is assessed and the network's spatial configuration are key factors determining the degree of biodegradation improvement. Our results support the idea of stimulating the establishment of fungal mycelia for enhanced bioremediation of polluted soils. - Highlights: → Bacterial dispersal networks can considerably improve biodegradation performance. → They facilitate bacterial access to dispersal-limited areas and remote resources. → Abiotic conditions, time horizon and network structure govern the improvements. → Stimulating the establishment of fungal mycelia promises enhanced soil remediation. - Simulation modelling demonstrates that fungus-mediated bacterial dispersal can considerably improve the bioavailability of organic pollutants under spatially heterogeneous abiotic conditions typical for water-unsaturated soils.

Dispersal networks for enhancing bacterial degradation in heterogeneous environments

Energy Technology Data Exchange (ETDEWEB)

Banitz, Thomas, E-mail: thomas.banitz@ufz.de [Department of Ecological Modelling, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Wick, Lukas Y.; Fetzer, Ingo [Department of Environmental Microbiology, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Frank, Karin [Department of Ecological Modelling, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Harms, Hauke [Department of Environmental Microbiology, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany); Johst, Karin [Department of Ecological Modelling, UFZ - Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig (Germany)

2011-10-15

Successful biodegradation of organic soil pollutants depends on their bioavailability to catabolically active microorganisms. In particular, environmental heterogeneities often limit bacterial access to pollutants. Experimental and modelling studies revealed that fungal networks can facilitate bacterial dispersal and may thereby improve pollutant bioavailability. Here, we investigate the influence of such bacterial dispersal networks on biodegradation performance under spatially heterogeneous abiotic conditions using a process-based simulation model. To match typical situations in polluted soils, two types of abiotic conditions are studied: heterogeneous bacterial dispersal conditions and heterogeneous initial resource distributions. The model predicts that networks facilitating bacterial dispersal can enhance biodegradation performance for a wide range of these conditions. Additionally, the time horizon over which this performance is assessed and the network's spatial configuration are key factors determining the degree of biodegradation improvement. Our results support the idea of stimulating the establishment of fungal mycelia for enhanced bioremediation of polluted soils. - Highlights: > Bacterial dispersal networks can considerably improve biodegradation performance. > They facilitate bacterial access to dispersal-limited areas and remote resources. > Abiotic conditions, time horizon and network structure govern the improvements. > Stimulating the establishment of fungal mycelia promises enhanced soil remediation. - Simulation modelling demonstrates that fungus-mediated bacterial dispersal can considerably improve the bioavailability of organic pollutants under spatially heterogeneous abiotic conditions typical for water-unsaturated soils.

Degradation of multiwall carbon nanotubes by bacteria

International Nuclear Information System (INIS)

Zhang, Liwen; Petersen, Elijah J.; Habteselassie, Mussie Y.; Mao, Liang; Huang, Qingguo

2013-01-01

Understanding the environmental transformation of multiwall carbon nanotubes (MWCNTs) is important to their life cycle assessment and potential environmental impacts. We report that a bacterial community is capable of degrading 14 C-labeled MWCNTs into 14 CO 2 in the presence of an external carbon source via co-metabolism. Multiple intermediate products were detected, and genotypic characterization revealed three possible microbial degraders: Burkholderia kururiensis, Delftia acidovorans, and Stenotrophomonas maltophilia. This result suggests that microbe/MWCNTs interaction may impact the long-term fate of MWCNTs. Highlights: •Mineralization of MWCNTs by a bacterial community was observed. •The mineralization required an external carbon source. •Multiple intermediate products were identified in the MWCNT degrading culture. •Three bacterial species were found likely responsible for MWCNT degradation. -- The 14 C-labeled multiwall carbon nanotubes can be degraded to 14 CO 2 and other byproducts by a bacteria community under natural conditions

Effect of biostimulation using sewage sludge, soybean meal and wheat straw on oil degradation and bacterial community composition in a contaminated desert soil

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Sumaiya eAl-Kindi

2016-03-01

Full Text Available Waste materials have a strong potential in the bioremediation of oil-contaminated sites, because of their richness in nutrients and their economical feasibility. We used sewage sludge, soybean meal and wheat straw to biostimulate oil degradation in a heavily contaminated desert soil. While oil degradation was assessed by following the produced CO2 and by using gas chromatography-mass spectrometry (GC-MS, shifts in bacterial community composition were monitored using illumina MiSeq. The addition of sewage sludge and wheat straw to the desert soil stimulated the respiration activities more than the addition of soybean meal. GC-MS analysis revealed that the addition of addition of sewage sludge and wheat straw resulted in 1.7 to 1.8 fold increase in the degraded C14 to C30 alkanes, compared to only 1.3 fold increase in the case of soybean meal addition. The degradation of ≥ 90% of the C14 to C30 alkanes were measured in the soils treated with sewage sludge and wheat straw. MiSeq sequencing revealed that the majority (76.5-86.4% of total sequences of acquired sequences from the original soil belonged to Alphaproteobacteria, Gammaproteobacteria and Firmicutes. Multivariate analysis of operational taxonomic units (OTUs placed the bacterial communities of the soils after the treatments in separate clusters (ANOSIM R=0.66, P=0.0001. The most remarkable shift in bacterial communities was in the wheat straw treatment, where 95-98% of the total sequences belonging to Bacilli. We conclude that sewage sludge and wheat straw are useful biostimulating agents for the cleanup of oil-contaminated desert soils.

Brood size modifications affect plumage bacterial assemblages of European starlings.

Science.gov (United States)

Lucas, Françoise S; Moureau, Benoit; Jourdie, Violaine; Heeb, Philipp

2005-02-01

During reproduction, birds face trade-offs between time and energy devoted to parental effort and traits associated with self-maintenance. We manipulated brood sizes to investigate the effects of such trade-offs on feather bacterial densities and the structure of bacterial assemblages on feathers in adult European starlings, Sturnus vulgaris, and in vitro feather degradation. As predicted by a trade-off between parental effort and self-maintenance, we found that birds with enlarged broods had more free-living bacteria on their feathers than birds with reduced broods. Furthermore, we found a significant interaction between brood manipulation and original brood size on free-living bacterial densities suggesting that the trade-off is mediated by the adults' initial reproductive investment. In contrast, brood size manipulations had no significant effect on densities of attached bacteria. Using ribosomal intergenic spacer analysis (RISA), we demonstrated that brood manipulations significantly modified the structure (band pattern) of feather-degrading bacterial assemblages, but had no significant effect on their richness (number of bands) or the in vitro feather degradation. In vitro feather degradation varied in relation to the premanipulation brood size and positively with the richness of the feather degrading bacterial community. Besides brood manipulation effect, we found that ecological factors and individual traits, such as the age, the nest location or the capture date, shaped bacterial assemblages and feather degradation capacities.

Phylogenetic and functional diversity of metagenomic libraries of phenol degrading sludge from petroleum refinery wastewater treatment system.

Science.gov (United States)

Silva, Cynthia C; Hayden, Helen; Sawbridge, Tim; Mele, Pauline; Kruger, Ricardo H; Rodrigues, Marili Vn; Costa, Gustavo Gl; Vidal, Ramon O; Sousa, Maíra P; Torres, Ana Paula R; Santiago, Vânia Mj; Oliveira, Valéria M

2012-03-27

In petrochemical refinery wastewater treatment plants (WWTP), different concentrations of pollutant compounds are received daily in the influent stream, including significant amounts of phenolic compounds, creating propitious conditions for the development of particular microorganisms that can rapidly adapt to such environment. In the present work, the microbial sludge from a refinery WWTP was enriched for phenol, cloned into fosmid vectors and pyrosequenced. The fosmid libraries yielded 13,200 clones and a comprehensive bioinformatic analysis of the sequence data set revealed a complex and diverse bacterial community in the phenol degrading sludge. The phylogenetic analyses using MEGAN in combination with RDP classifier showed a massive predominance of Proteobacteria, represented mostly by the genera Diaphorobacter, Pseudomonas, Thauera and Comamonas. The functional classification of phenol degrading sludge sequence data set generated by MG-RAST showed the wide metabolic diversity of the microbial sludge, with a high percentage of genes involved in the aerobic and anaerobic degradation of phenol and derivatives. In addition, genes related to the metabolism of many other organic and xenobiotic compounds, such as toluene, biphenyl, naphthalene and benzoate, were found. Results gathered herein demonstrated that the phenol degrading sludge has complex phylogenetic and functional diversities, showing the potential of such community to degrade several pollutant compounds. This microbiota is likely to represent a rich resource of versatile and unknown enzymes which may be exploited for biotechnological processes such as bioremediation.

Effect of Biostimulation Using Sewage Sludge, Soybean Meal, and Wheat Straw on Oil Degradation and Bacterial Community Composition in a Contaminated Desert Soil

Science.gov (United States)

Al-Kindi, Sumaiya; Abed, Raeid M. M.

2016-01-01

Waste materials have a strong potential in the bioremediation of oil-contaminated sites, because of their richness in nutrients and their economical feasibility. We used sewage sludge, soybean meal, and wheat straw to biostimulate oil degradation in a heavily contaminated desert soil. While oil degradation was assessed by following the produced CO2 and by using gas chromatography–mass spectrometry (GC–MS), shifts in bacterial community composition were monitored using illumina MiSeq. The addition of sewage sludge and wheat straw to the desert soil stimulated the respiration activities to reach 3.2–3.4 times higher than in the untreated soil, whereas the addition of soybean meal resulted in an insignificant change in the produced CO2, given the high respiration activities of the soybean meal alone. GC–MS analysis revealed that the addition of sewage sludge and wheat straw resulted in 1.7–1.8 fold increase in the degraded C14 to C30 alkanes, compared to only 1.3 fold increase in the case of soybean meal addition. The degradation of ≥90% of the C14 to C30 alkanes was measured in the soils treated with sewage sludge and wheat straw. MiSeq sequencing revealed that the majority (76.5–86.4% of total sequences) of acquired sequences from the untreated soil belonged to Alphaproteobacteria, Gammaproteobacteria, and Firmicutes. Multivariate analysis of operational taxonomic units placed the bacterial communities of the soils after the treatments in separate clusters (ANOSIM R = 0.66, P = 0.0001). The most remarkable shift in bacterial communities was in the wheat straw treatment, where 95–98% of the total sequences were affiliated to Bacilli. We conclude that sewage sludge and wheat straw are useful biostimulating agents for the cleanup of oil-contaminated desert soils. PMID:26973618

Effects of surfactants on bacteria and the bacterial degradation of alkanes in crude oil

Energy Technology Data Exchange (ETDEWEB)

Bruheim, Per

1998-12-31

This thesis investigates the effects of surfactants on the bacterial degradation of alkanes in crude oil. Several alkane oxidising Gram positive and Gram negative were tested for their abilities to oxidise alkanes in crude oil emulsified with surfactants. The surfactants used to make the oil in water emulsions were either of microbial or chemical origin. Oxidation rates of resting bacteria oxidising various crude oil in water emulsions were measured by Warburg respirometry. The emulsions were compared with non-emulsified oil to see which was the preferred substrate. The bacteria were pregrown to both the exponential and stationary phase of growth before harvesting and preparation for the Warburg experiments. 123 refs., 4 figs., 14 tabs.

The complete multipartite genome sequence of Cupriavidus necator JMP134, a versatile pollutant degrader.

Directory of Open Access Journals (Sweden)

Athanasios Lykidis

Full Text Available BACKGROUND: Cupriavidus necator JMP134 is a Gram-negative beta-proteobacterium able to grow on a variety of aromatic and chloroaromatic compounds as its sole carbon and energy source. METHODOLOGY/PRINCIPAL FINDINGS: Its genome consists of four replicons (two chromosomes and two plasmids containing a total of 6631 protein coding genes. Comparative analysis identified 1910 core genes common to the four genomes compared (C. necator JMP134, C. necator H16, C. metallidurans CH34, R. solanacearum GMI1000. Although secondary chromosomes found in the Cupriavidus, Ralstonia, and Burkholderia lineages are all derived from plasmids, analyses of the plasmid partition proteins located on those chromosomes indicate that different plasmids gave rise to the secondary chromosomes in each lineage. The C. necator JMP134 genome contains 300 genes putatively involved in the catabolism of aromatic compounds and encodes most of the central ring-cleavage pathways. This strain also shows additional metabolic capabilities towards alicyclic compounds and the potential for catabolism of almost all proteinogenic amino acids. This remarkable catabolic potential seems to be sustained by a high degree of genetic redundancy, most probably enabling this catabolically versatile bacterium with different levels of metabolic responses and alternative regulation necessary to cope with a challenging environment. From the comparison of Cupriavidus genomes, it is possible to state that a broad metabolic capability is a general trait for Cupriavidus genus, however certain specialization towards a nutritional niche (xenobiotics degradation, chemolithoautotrophy or symbiotic nitrogen fixation seems to be shaped mostly by the acquisition of "specialized" plasmids. CONCLUSIONS/SIGNIFICANCE: The availability of the complete genome sequence for C. necator JMP134 provides the groundwork for further elucidation of the mechanisms and regulation of chloroaromatic compound biodegradation.

Impact of protists on a hydrocarbon-degrading bacterial community from deep-sea Gulf of Mexico sediments: A microcosm study

Science.gov (United States)

Beaudoin, David J.; Carmichael, Catherine A.; Nelson, Robert K.; Reddy, Christopher M.; Teske, Andreas P.; Edgcomb, Virginia P.

2016-07-01

In spite of significant advancements towards understanding the dynamics of petroleum hydrocarbon degrading microbial consortia, the impacts (direct or indirect via grazing activities) of bacterivorous protists remain largely unknown. Microcosm experiments were used to examine whether protistan grazing affects the petroleum hydrocarbon degradation capacity of a deep-sea sediment microbial community from an active Gulf of Mexico cold seep. Differences in n-alkane content between native sediment microcosms and those treated with inhibitors of eukaryotes were assessed by comprehensive two-dimensional gas chromatography following 30-90 day incubations and analysis of shifts in microbial community composition using small subunit ribosomal RNA gene clone libraries. More biodegradation was observed in microcosms supplemented with eukaryotic inhibitors. SSU rRNA gene clone libraries from oil-amended treatments revealed an increase in the number of proteobacterial clones (particularly γ-proteobacteria) after spiking sediments with diesel oil. Bacterial community composition shifted, and degradation rates increased, in treatments where protists were inhibited, suggesting protists affect the hydrocarbon degrading capacity of microbial communities in sediments collected at this Gulf of Mexico site.

Blue-light-emitting organic electroluminescence via exciplex emission based on a fluorene derivative

International Nuclear Information System (INIS)

Li Fushan; Chen Zhijian; Wei Wei; Cao Huayu; Gong Qihuang; Teng Feng; Qian Lei; Wang Yuanmin

2004-01-01

The synthesis of a high photoluminescence efficiency (88%, compared with tris(8-hydroxyquinoline)(Alq 3 )) organic material 9,9-Dibutyl-N,N,N,N-tetraphenyl-9H-fluorene-2,7-diamine (DTFD) via Ullmann condensation was reported. Exiciplex emission of the ITO/DTFD/2,2-[1,2-phenylenebis(oxy)]bis(N,N-diphenylacetamide)/Alq 3 /LiF/Al device was observed and the peak wavelength of the emission was measured to be 480 nm, which belongs to the blue region. A turn-on voltage as low as 4 V and maximal brightness as large as 400 cd m -2 were measured. The electroluminescence spectrum was observed to be blue-shifted with increase in applied voltage

Blue-light-emitting organic electroluminescence via exciplex emission based on a fluorene derivative

Energy Technology Data Exchange (ETDEWEB)

Li Fushan [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Chen Zhijian [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Wei Wei [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Cao Huayu [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Gong Qihuang [Department of Physics, State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, Peking University, 100871 (China); Teng Feng [Institute of Optoelectronic Technology, Northern Jiaotong University, Beijing 100044 (China); Qian Lei [Institute of Optoelectronic Technology, Northern Jiaotong University, Beijing 100044 (China); Wang Yuanmin [Institute of Optoelectronic Technology, Northern Jiaotong University, Beijing 100044 (China)

2004-06-21

The synthesis of a high photoluminescence efficiency (88%, compared with tris(8-hydroxyquinoline)(Alq{sub 3})) organic material 9,9-Dibutyl-N,N,N,N-tetraphenyl-9H-fluorene-2,7-diamine (DTFD) via Ullmann condensation was reported. Exiciplex emission of the ITO/DTFD/2,2-[1,2-phenylenebis(oxy)]bis(N,N-diphenylacetamide)/Alq{sub 3}/LiF/Al device was observed and the peak wavelength of the emission was measured to be 480 nm, which belongs to the blue region. A turn-on voltage as low as 4 V and maximal brightness as large as 400 cd m{sup -2} were measured. The electroluminescence spectrum was observed to be blue-shifted with increase in applied voltage.

Investigation on paper cup waste degradation by bacterial consortium and Eudrillus eugeinea through vermicomposting.

Science.gov (United States)

Arumugam, Karthika; Renganathan, Seenivasagan; Babalola, Olubukola Oluranti; Muthunarayanan, Vasanthy

2018-04-01

Disposable Paper cups are a threat to the environment and are composed of 90% high strength paper with 5% thin coating of polyethylene. This polyethylene prevents the paper cup from undergoing degradation in the soil. Hence, in the present study two different approaches towards the management of paper cup waste through vermicomposting technology has been presented. The experimental setup includes 2 plastic reactors namely Vermicompost (VC) (Cow dung + Paper cup waste + Earthworm (Eudrillus eugeinea)) and Vermicompost with bacterial consortium (VCB) (Cow dung + Paper cup waste + Eudrillus eugeinea + Microbial consortia such as Bacillus anthracis, B. endophyticus, B. funiculus, B. thuringiensis, B. cereus, B. toyonensis, Virigibacillius chiquenigi, Acinetobacter baumanni and Lactobacillus pantheries). After treatment the physicochemical parameters were analysed. The results showed that the values of TOC (26.52 and 37.47%), TOM (36.01 and 33.13%) and C/N (15.02 and 11.92%) ratio are reduced in both VC and VCB whereas, the values of pH (8.01 and 7.56), EC (1.2-1.9 µs -1 and 1.4-1.9 µs -1 ), TP (46.1 and 51%), TMg (50.52 and 64.3%), TCa (50 and 64%), TNa (1.39 and 1.75%) and TK (1.75 and 1.86%) have increased. This study substantiates the addition of the microbial consortia augmenting the degradation in VCB reactor by reducing the period of process from 19 to 12 weeks. Further the characterisation of the vermicompost prepared from paper cup with FT-IR shows high degradation of carboxylic and aliphatic group; SEM analysis shows the disaggregation of cellulose and lignin; XRD shows the degradation of cellulose. All these analyses endorse the degradation of the paper cup waste faster with microbes (VCB). Thus, this present study high lights management of the paper cup waste in a relatively short period of time. Copyright © 2017 Elsevier Ltd. All rights reserved.

Solar-energy production and energy-efficient lighting: photovoltaic devices and white-light-emitting diodes using poly(2,7-fluorene), poly(2,7-carbazole), and poly(2,7-dibenzosilole) derivatives.

Science.gov (United States)

Beaupré, Serge; Boudreault, Pierre-Luc T; Leclerc, Mario

2010-02-23

World energy needs grow each year. To address global warming and climate changes the search for renewable energy sources with limited greenhouse gas emissions and the development of energy-efficient lighting devices are underway. This Review reports recent progress made in the synthesis and characterization of conjugated polymers based on bridged phenylenes, namely, poly(2,7-fluorene)s, poly(2,7-carbazole)s, and poly(2,7-dibenzosilole)s, for applications in solar cells and white-light-emitting diodes. The main strategies and remaining challenges in the development of reliable and low-cost renewable sources of energy and energy-saving lighting devices are discussed.

Probing bacterial adhesion at the single-cell level

DEFF Research Database (Denmark)

Zeng, Guanghong; Müller, Torsten; Meyer, Rikke Louise

be considered. We have developed a simple and versatile method to make single-cell bacterial probes for measuring single cell adhesion by force spectroscopy using atomic force microscopy (AFM). A single-cell probe was readily made by picking up a bacterial cell from a glass surface by approaching a tipless AFM...... cantilever coated with the commercial cell adhesive CellTakTM. We applied the method to study adhesion of living cells to abiotic surfaces at the single-cell level. Immobilisation of single bacterial cells to the cantilever was stable for several hours, and viability was confirmed by Live/Dead staining...... on the adhesion force, we explored the bond formation and adhesive strength of four different bacterial strains towards three abiotic substrates with variable hydrophobicity and surface roughness. The adhesion force and final rupture length were dependent on bacterial strains, surfaces properties, and time...

A new processable electrochromic polymer based on an electron deficient fluorene derivative with a high coloration efficiency

International Nuclear Information System (INIS)

Çarbaş, Buket Bezgin; Kivrak, Arif; Önal, Ahmet M.

2011-01-01

Highlights: ► Electrochemical synthesis and elecroptical properties of a new soluble polymer based on fluorenone and 3,4-propylenedioxythiophene are highlighted. ► The polymer film exhibits reversible electrochromic behavior and both p and n dopable. ► In addition it has high electrochemical stability and coloration efficiency. ► In THF, polymer film emits orange light when excited at 355 nm. - Abstract: A new fluorenone based soluble polymer, namely poly(2,7-bis-(3,3-dihexyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl) -fluoren-9-one) (PPFP), containing propylenedioxythiophene (ProDOT) as a donor and fluorenone (FO) as an acceptor group is highlighted. Electrochemical polymerization of 2,7-bis-(3,3-dihexyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl) -fluoren-9-one (PFP) was achieved in dichloromethane/acetonitrile mixture with 0.1 M tetrabutylammonium hexafluorophosphate via potential cycling. The polymer shows an electrochromic behavior, a color change from orange to dark blue during oxidation with a high coloration efficiency (422 cm 2 /C at 684 nm) and orange to yellow during reduction with high optical and electrochemical stability as compared to its close analogues, in addition it is found to be both p and n dopable. Furthermore, this soluble polymer exhibits fluorescent properties (the emission of orange light (578 nm) in THF solution).

Soluble Electrochromic Polymers Incorporating Benzoselenadiazole and Electron Donor Units (Carbazole or Fluorene: Synthesis and Electronic-Optical Properties

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Jianzhong Xu

2018-04-01

Full Text Available A series of π-conjugated polymers containing alternating benzoselenadiazole (BSe-bi(thiophene derivative-carbazole or benzoththiadiazole (BSe-bi(thiophene derivative-fluorene units were designed and synthesized. Thiophene derivatives, namely 3-hexylthiophene, 3,4-bihexyloxythiophene, and 3,4-bioctyloxythiophene, were used as the π-bridges of the polymers. The polymers were characterized in detail in terms of their thermal stabilities, cyclic voltammograms, UV-Vis absorption, spectroelectrochemistry, dynamic switching property and so forth. The alkoxy thiophene π-bridged polymers have lower onset oxidation potentials and bandgaps than that of their corresponding alkyl thiophene π-bridged polymers. The selection of the donor units between the carbazole and the fluorene units has nearly no effect on the bandgaps and colors as well as the onset oxidation potentials of the polymers. The increase in the length of the side alkyl chains on the thiophene ring caused a slight increase in the polymer bandgap, which may be caused by the space hindrance effect. The dynamic switching abilities of the polymers were obtained by the chronoabsorptometry method, and the results also suggested that the alkoxy thiophene-containing polymers (as π-bridges have higher contrast ratios than the corresponding alkyl thiophene-containing polymers. Furthermore, the increase in the length of the side alkyl chain might have a detrimental effect on the optical contrast ratios of the polymers.

Effects of dietary protein levels and 2-methylbutyrate on ruminal fermentation, nutrient degradability, bacterial populations and urinary purine derivatives in Simmental steers.

Science.gov (United States)

Wang, C; Liu, Q; Guo, G; Huo, W J; Pei, C X; Zhang, S L; Yang, W Z

2018-06-01

The objective of this study was to evaluate the effects of dietary crude protein (CP) levels and 2-methylbutyrate (MB) supplementation on ruminal fermentation, bacterial populations, microbial enzyme activity and urinary excretion of purine derivatives (PD) in Simmental steers. Eight ruminally cannulated Simmental steers, averaging 18 months of age and 465 ± 8.6 kg of body weight (BW), were used in a replicated 4 × 4 Latin square design by a 2 × 2 factorial arrangement. Low protein (98.5 g CP/kg dry matter [LP] or high protein (128.7 g CP/kg dry matter [HP]) diets were fed with MB supplementation (0 g [MB-] or 16.8 g steer -1  day -1 [MB+]). Steers were fed a total mixed ration with dietary corn straw to concentrate ratio of 50:50 (dry matter [DM] basis). The CP × MB interaction was observed for ruminal total VFA, molar proportions of acetate and propionate, acetate to propionate ratio, ammonia-N, effective degradability of neutral detergent fibre (NDF) and CP, microbial enzyme activity, bacterial populations and total PD excretion (p Ruminal pH decreased (p ruminal total VFA concentration increased (p Ruminal ammonia-N content increased (p = .034) with increasing dietary CP level, but decreased (p = .012) with MB supplementation. The effective degradability of NDF and CP increased (p ruminal fermentation, nutrient degradability, microbial enzyme activity, ruminal bacterial populations and microbial protein synthesis improved with increasing dietary CP level or MB supplementation in steers. © 2017 Blackwell Verlag GmbH.

Conjugated Polymers Containing BODIPY and Fluorene Units for Sensitive Detection of CN− Ions: Site-Selective Synthesis, Photo-Physical and Electrochemical Properties

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Tian He

2017-10-01

Full Text Available Conjugated polymers containing distinct molecular units are expected to be very interesting because of their unique properties endowed by these units and the formed conjugated polymers. Herein, four new conjugated copolymers based on fluorene and 4,4’-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY have been designed and synthesized via Sonogashira polymerization. The fluorene unit was attached to the 3,5- or 2,6-positions of BODIPY by ethynylenes or p-diacetylenebenzene. The obtained polymers show good thermal stability and broad absorption in the wavelength range from 300 to 750 nm. The effects of site-selective copolymerization and conjugation length along the polymer backbone on the optoelectronic and electrochemical properties of these copolymers were systematically studied by UV-Vis spectroscopy, photoluminescence (PL and cyclic voltammetry. Besides, it is found that the BODIPY-based copolymers exhibit selectively sensitive responses to cyanide anions, resulting in obvious change of UV-Vis absorption spectra and significant fluorescence quenching of the polymers among various common anions.

Stability of a biogas-producing bacterial, archaeal and fungal community degrading food residues.

Science.gov (United States)

Bengelsdorf, Frank R; Gerischer, Ulrike; Langer, Susanne; Zak, Manuel; Kazda, Marian

2013-04-01

The resident microbiota was analyzed in a mesophilic, continuously operating biogas plant predominantly utilizing food residues, stale bread, and other waste cosubstrates together with pig manure and maize silage. The dominating bacterial, archaeal, and eukaryotic community members were characterized by two different 16S/18S rRNA gene culture-independent approaches. Prokaryotic 16S rRNA gene and eukaryotic 18S rRNA gene clone libraries were constructed and further analyzed by restriction fragment length polymorphism (RFLP), 16S/18S rRNA gene sequencing, and phylogenetic tree reconstruction. The most dominant bacteria belonged to the phyla Bacteriodetes, Chloroflexus, and Firmicutes. On the family level, the bacterial composition confirmed high differences among biogas plants studied so fare. In contrast, the methanogenic archaeal community was similar to that of other studied biogas plants. Furthermore, it was possible to identify fungi at the genus level, namely Saccharomyces and Mucor. Both genera, which are important for microbial degradation of complex compounds, were up to now not found in biogas plants. The results revealed their long-term presence as indicated by denaturating gradient gel electrophoresis (DGGE). The DGGE method confirmed that the main members of the microbial community were constantly present over more than one-year period. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Bacterial carbohydrate-degrading capacity in foal faeces: changes from birth to pre-weaning and the impact of maternal supplementation with fermented feed products.

Science.gov (United States)

Faubladier, Céline; Julliand, Véronique; Danel, Justine; Philippeau, Christelle

2013-09-28

The present study aimed at (1) describing age-related changes in faecal bacterial functional groups involved in carbohydrate degradation and in their activities in foals (n 10) from birth (day (d) 0) to 6 months (d180) and (2) investigating the effect of maternal supplementation (five mares per treatment) from d - 45 to d60 with fermented feed products on response trends over time of the foal bacterial carbohydratedegrading capacity. Maternal supplementation with fermented feed products stimulated foal growth from d0 to d60 and had an impact on the establishment of some digestive bacterial groups and their activities in foals from d0 to d5 but not in the longer term. Irrespective of the maternal treatment, total bacteria, total anaerobic, lactate-utilising and amylolytic bacteria were established immediately after birth (Panaerobes and lactate utilisers were established rapidly between d0 and d2 (P=0·021 and 0·066, respectively) and the increase in the percentage of propionate occurred earlier (P=0·013). Maternal supplementation had no effect on the establishment of fibrolytic bacteria and their activity. Cellulolytic bacteria and Fibrobacter succinogenes first appeared at d2 and d5, and increased progressively, reaching stable values at d30 and d60, respectively. From the second week of life, the increase in the molar percentage of acetate and the ratio (acetate + butyrate):propionate (P<0·05) suggested that fibrolytic activity had begun. From d60, only minor changes in bacterial composition and activities occurred, showing that the bacterial carbohydrate-degrading capacity was established at 2 months of age.

Proteogenomic Characterization of Monocyclic Aromatic Hydrocarbon Degradation Pathways in the Aniline-Degrading Bacterium Burkholderia sp. K24.

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Sang-Yeop Lee

Full Text Available Burkholderia sp. K24, formerly known as Acinetobacter lwoffii K24, is a soil bacterium capable of utilizing aniline as its sole carbon and nitrogen source. Genomic sequence analysis revealed that this bacterium possesses putative gene clusters for biodegradation of various monocyclic aromatic hydrocarbons (MAHs, including benzene, toluene, and xylene (BTX, as well as aniline. We verified the proposed MAH biodegradation pathways by dioxygenase activity assays, RT-PCR, and LC/MS-based quantitative proteomic analyses. This proteogenomic approach revealed four independent degradation pathways, all converging into the citric acid cycle. Aniline and p-hydroxybenzoate degradation pathways converged into the β-ketoadipate pathway. Benzoate and toluene were degraded through the benzoyl-CoA degradation pathway. The xylene isomers, i.e., o-, m-, and p-xylene, were degraded via the extradiol cleavage pathways. Salicylate was degraded through the gentisate degradation pathway. Our results show that Burkholderia sp. K24 possesses versatile biodegradation pathways, which may be employed for efficient bioremediation of aniline and BTX.

Proteogenomic Characterization of Monocyclic Aromatic Hydrocarbon Degradation Pathways in the Aniline-Degrading Bacterium Burkholderia sp. K24

Science.gov (United States)

Yun, Sung Ho; Choi, Chi-Won; Yi, Yoon-Sun; Kim, Jonghyun; Chung, Young-Ho; Park, Edmond Changkyun; Kim, Seung Il

2016-01-01

Burkholderia sp. K24, formerly known as Acinetobacter lwoffii K24, is a soil bacterium capable of utilizing aniline as its sole carbon and nitrogen source. Genomic sequence analysis revealed that this bacterium possesses putative gene clusters for biodegradation of various monocyclic aromatic hydrocarbons (MAHs), including benzene, toluene, and xylene (BTX), as well as aniline. We verified the proposed MAH biodegradation pathways by dioxygenase activity assays, RT-PCR, and LC/MS-based quantitative proteomic analyses. This proteogenomic approach revealed four independent degradation pathways, all converging into the citric acid cycle. Aniline and p-hydroxybenzoate degradation pathways converged into the β-ketoadipate pathway. Benzoate and toluene were degraded through the benzoyl-CoA degradation pathway. The xylene isomers, i.e., o-, m-, and p-xylene, were degraded via the extradiol cleavage pathways. Salicylate was degraded through the gentisate degradation pathway. Our results show that Burkholderia sp. K24 possesses versatile biodegradation pathways, which may be employed for efficient bioremediation of aniline and BTX. PMID:27124467

Comparative Genomics of the Ubiquitous, Hydrocarbon-degrading Genus Marinobacter

Science.gov (United States)

Singer, E.; Webb, E.; Edwards, K. J.

2012-12-01

using fimbriae and pili. Formation of biofilm with biosurfactant characteristics has been observed in Marinobacter cultures and environmental strains in relation to hydrocarbon degradation. Genomic potential exists for the synthesis of biofilm-related carbon and energy storage compounds, e.g. alginate and isoprenoid wax esters, and quorum sensing encoded by the regulatory luxR gene and N-acyl-L-homoserine lactone (AHL) signals. Halotolerance is predicted to be achieved through biosynthesis and/or import of compatible solutes, including glycine betaine, choline, ectoine, sucrose, periplasmic glucans as well as membrane channel activity regulating intracellular sodium, potassium and chloride concentration balance. Gene abundances concur with those observed in sequenced halophilic Halomonas genomes. Defense mechanisms are plentiful and include arsenate, organic solvent, copper, and mercuric resistance, compounds, which frequently occur in oil refinery wastewater. The Marinobacter genomes reflect dynamic environments and diverse interactions with viruses and other bacteria with similar metabolic strategies, as reflected by the large number of integrases and transposases. This study has provided comprehensive genomic insights into the metabolic versatility and predicted environmental impact potential of one of the most ubiquitous bacterial genera.

Synthesis of electro-optically active polymer composite of poly[2,2'-bis(3,4-ethylenedioxythiophene-alt-fluorene]/hydroxypropyl cellulose showing liquid crystal structure

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N. Eguchi

2017-10-01

Full Text Available Electrochemical preparation of a composite consisting of poly[2,2′-bis(3,4-ethylenedioxythiophene-alt-fluorene] and hydroxypropyl cellulose (PEFE/HPC was carried out. We conducted electrochemical polymerization of poly[2,2′-bis(3,4-ethylenedioxythiophene-alt-fluorene] (EFE as a monomer in a lyotropic liquid crystal of HPC. We used an organic solvent instead of water for lyotropic liquid crystal medium to expand the possibility of the range of monomers, although water is usually employed as a solvent for HPC for showing liquid crystallinity. Here, we employed N,N-dimethylformamide (DMF as a solvent for HPC. Electrochemical polymerization in the polymer liquid crystal was carried out to obtain a polymer film with liquid crystal order. The polymer film thus prepared exhibited optical activity. Fourier transfer infrared (FT-IR absorption spectroscopy reveals that the film is a composite consisting of HPC and polymer. The composite PEFE/HPC thus prepared in HPC/DMF system showed electrochromism.

Abundance and activity of oil-degrading and indigenous bacteria in sediment microcosms

International Nuclear Information System (INIS)

Araujo, R.; Molina, M.; Bachoon, D.

1995-01-01

The responses of bacterial community composition and degradation crude oil to applications of bioremediation products and plant detrital material were investigated in wetlands microcosms. The microcosms were constructed of sieved sediments and operated as tidal marshes. Products included nutrients, organisms, surfactants and combinations thereof; dried ground Spartina was the source of detrital material. Plate count and most probable-number techniques were used to enumerate microbial populations and GC/MS analysis of indicator petroleum hydrocarbons was used to assess oil degradation. Microbial communities were characterized by whole-genome hybridization and specific probes for bacterial groups, including Pseudomonas, Streptomycetes, Vibrio, and sulfate-reducing bacteria. Although the total microbial numbers were similar in all bioremediation treatments, the numbers of oil degraders increased two to three log units in the fertilizer and microbial-degrader-enriched treatments. Oil-degraders comprised the largest fraction of the total population in the treatment amended with microbial degraders, apparently at the expense of indigenous bacteria, as indicated by specific probes. Oil-degraders were also detected in the subsurface in all treatments except the controls. The extent of oil degradation was not consistent with bacterial numbers; only nutrient additions resulted in significantly enhanced degradation of oil. After 1 month of microcosm operation, oil-degraders had increased at least two orders of magnitude in sediment surface layers when oil was added alone or with Spartina detritus, although total bacterial numbers and the number of oil-degraders decreased to near initial levels by 2 months. The peak coincides with bacterial utilization of the alkane fraction of petroleum hydrocarbons

Destruction of acenaphthene, fluorene, anthracene and pyrene by a dc gliding arc plasma reactor

International Nuclear Information System (INIS)

Yu Liang; Tu Xin; Li Xiaodong; Wang Yu; Chi Yong; Yan Jianhua

2010-01-01

In this study, four kinds of PAHs (polycyclic aromatic hydrocarbons) i.e. acenaphthene, fluorene, anthracene and pyrene are used as targets for investigation of PAHs treatment process assisted by dc gliding arc discharge. The effects of carrier gas and external resistance on the PAHs decomposition process are discussed. The results indicate that the destruction rate can be achieved to the highest with the carrier gas of oxygen and the external resistance of 50 kΩ independent of type of PAHs. Furthermore, experimental results suggest that destruction energy efficiency of gliding arc plasma would be improved by treating higher concentration pollutants. Based on the analysis of experimental results, possible destruction mechanisms in different gas discharge are discussed.

Bacterial populations and environmental factors controlling cellulose degradation in an acidic Sphagnum peat.

Science.gov (United States)

Pankratov, Timofey A; Ivanova, Anastasia O; Dedysh, Svetlana N; Liesack, Werner

2011-07-01

Northern peatlands represent a major global carbon store harbouring approximately one-third of the global reserves of soil organic carbon. A large proportion of these peatlands consists of acidic Sphagnum-dominated ombrotrophic bogs, which are characterized by extremely low rates of plant debris decomposition. The degradation of cellulose, the major component of Sphagnum-derived litter, was monitored in long-term incubation experiments with acidic (pH 4.0) peat extracts. This process was almost undetectable at 10°C and occurred at low rates at 20°C, while it was significantly accelerated at both temperature regimes by the addition of available nitrogen. Cellulose breakdown was only partially inhibited in the presence of cycloheximide, suggesting that bacteria participated in this process. We aimed to identify these bacteria by a combination of molecular and cultivation approaches and to determine the factors that limit their activity in situ. The indigenous bacterial community in peat was dominated by Alphaproteobacteria and Acidobacteria. The addition of cellulose induced a clear shift in the community structure towards an increase in the relative abundance of the Bacteroidetes. Increasing temperature and nitrogen availability resulted in a selective development of bacteria phylogenetically related to Cytophaga hutchinsonii (94-95% 16S rRNA gene sequence similarity), which densely colonized microfibrils of cellulose. Among isolates obtained from this community only some subdivision 1 Acidobacteria were capable of degrading cellulose, albeit at a very slow rate. These Acidobacteria represent indigenous cellulolytic members of the microbial community in acidic peat and are easily out-competed by Cytophaga-like bacteria under conditions of increased nitrogen availability. Members of the phylum Firmicutes, known to be key players in cellulose degradation in neutral habitats, were not detected in the cellulolytic community enriched at low pH. © 2011 Society for

The Potency of Local Bacterial Isolates Encapsulated Within Sodium Alginate in Carbofuran Degradation

Science.gov (United States)

Priyani, Nunuk; Pratiwi, Dian; Suryanto, Dwi

2018-03-01

Research on the viability of bacteria encapsulated within sodium alginate and their potential in carbofuran degradation has been done. A total of 8 bacterial isolates have been isolated from slaughter house waste. A 100 ml of Bushnell-Hass Broth (BHB) medium containing 146.982 ppm of carbofuran was used as a medium. As much as 2 gr of beads which equal to 108cells.ml‑1 was inoculated into each medium culture and incubated for 15 days at ambient temperature and was shaken at 100 rpm. Analysis of carbofuran residues using High Performance Liquid Chromatography (HPLC) showed that the best 2 isolates, DN 1 and OR 2, were able to decrease carbofuran phenol concentration up to 30.37 % and 32.09% respectively compared to control. These results suggested that no significant different from the ability of free cell which decreased carbofuran phenol concentration up to 32.54% and 28.29%.

Study of the electronic structure at the interface between fluorene-1-carboxylic acid molecules and Cu(110)

International Nuclear Information System (INIS)

Song Fei; Mao Hongying; Guan Dandan; Dou Weidong; Zhang Hanjie; Li Haiyang; He Pimo; Bao Shining; Hofmann, Philip

2009-01-01

The interface electronic properties of fluorene-1-carboxylic acid (FC-1) adsorbed on Cu(110) have been studied by ultraviolet photoemission spectroscopy (UPS) and first-principles calculations. Both the molecular orbitals and the Cu valence band are significantly modified upon adsorption. FC-1 is chemically bonded to Cu(110) through charge donation and back donation involving the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) of the molecule. An observed reduction of the work function can be attributed to the adsorption induced charge redistribution, and the positive interface dipole.

Bacterial enzymes involved in lignin degradation

NARCIS (Netherlands)

de Gonzalo, Gonzalo; Colpa, Dana I; Habib, Mohamed H M; Fraaije, Marco W

2016-01-01

Lignin forms a large part of plant biomass. It is a highly heterogeneous polymer of 4-hydroxyphenylpropanoid units and is embedded within polysaccharide polymers forming lignocellulose. Lignin provides strength and rigidity to plants and is rather resilient towards degradation. To improve the

Dominant petroleum hydrocarbon-degrading bacteria in the Archipelago Sea in South-West Finland (Baltic Sea) belong to different taxonomic groups than hydrocarbon degraders in the oceans.

Science.gov (United States)

Reunamo, Anna; Riemann, Lasse; Leskinen, Piia; Jørgensen, Kirsten S

2013-07-15

The natural petroleum hydrocarbon degrading capacity of the Archipelago Sea water in S-W Finland was studied in a microcosm experiment. Pristine and previously oil exposed sites were examined. Bacterial community fingerprinting was performed using terminal restriction fragment length polymorphism (T-RFLP) and samples from selected microcosms were sequenced. The abundance of PAH degradation genes was measured by quantitative PCR. Bacterial communities in diesel exposed microcosms diverged from control microcosms during the experiment. Gram positive PAH degradation genes dominated at both sites in situ, whereas gram negative PAH degrading genes became enriched in diesel microcosms. The dominant bacterial groups after a 14 days of diesel exposure were different depending on the sampling site, belonging to the class Actinobacteria (32%) at a pristine site and Betaproteobacteria (52%) at a previously oil exposed site. The hydrocarbon degrading bacteria in the Baltic Sea differ from those in the oceans, where most hydrocarbon degraders belong to Gammaproteobacteria. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bacterial degradation of naphtha and its influence on corrosion

International Nuclear Information System (INIS)

Rajasekar, A.; Maruthamuthu, S.; Muthukumar, N.; Mohanan, S.; Subramanian, P.; Palaniswamy, N.

2005-01-01

The degradation problem of naphtha arises since hydrocarbon acts as an excellent food source for a wide variety of microorganisms. Microbial activity leads to unacceptable level of turbidity, corrosion of pipeline and souring of stored product. In the present study, biodegradation of naphtha in the storage tank and its influence on corrosion was studied. The corrosion studies were carried out by gravimetric method. Uniform corrosion was observed from the weight loss coupons in naphtha (0.024 mm/yr) whereas in presence of naphtha with water, blisters (1.2052 mm/yr) were noticed. The naphtha degradation by microbes was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). IR study reveals the formation of primary alcohol during degradation process. It was found that microbes degrade (CH 2 -CH 2 ) n to R-CH 3 . Iron bacteria, manganese oxidizing bacteria, acid producers, and heterotrophic bacteria were enumerated and identified in the pipeline. SRB could not be noticed. Since water stratifies in the pipeline, the naphtha-degraded product may adsorb on pipeline, which would enhance the rate of microbial corrosion. On the basis of degradation and corrosion data, a hypothesis for microbial corrosion has been proposed

Bacterial consortia for crude oil spill remediation

International Nuclear Information System (INIS)

Chhatre, S.; Purohit, H.; Shanker, R.; Khanna, P.

1996-01-01

Oil spills generate enormous public concern and highlight the need for cost effective ad environmentally acceptable mitigation technologies. Physico-chemical methods are not completely effective after a spill. Hence, there is a need for improved and alternative technologies. Bioremediation is the most environmentally sound technology for clean up. This report intends to determine the potential of a bacterial consortium for degradation of Gulf and Bombay High crude oil. A four membered consortium was designed that could degrade 70% of the crude oil. A member of consortium produced a biosurfactant, rhamnolipid, that emulsified crude oil efficiently for effective degradation by the other members of consortium. The wide range of hydrocarbonoclastic capabilities of the selected members of bacterial consortium leads to the degradation of both aromatic and aliphatic fractions of crude oil in 72 hours. (Author)

Application of two bacterial strains for wastewater bioremediation and assessment of phenolics biodegradation.

Science.gov (United States)

Paisio, Cintia E; Quevedo, María R; Talano, Melina A; González, Paola S; Agostini, Elizabeth

2014-08-01

The use of native bacteria is a useful strategy to decontaminate industrial effluents. In this work, two bacterial strains isolated from polluted environments constitutes a promising alternative since they were able to remove several phenolic compounds not only from synthetic solutions but also from effluents derived from a chemical industry and a tannery which are complex matrices. Acinetobacter sp. RTE 1.4 showed ability to completely remove 2-methoxyphenol (1000 mg/L) while Rhodococcus sp. CS 1 not only degrade the same concentration of this compound but also removed 4- chlorophenol, 2,4-dichlorophenol and pentachlorophenol with high efficiency. Moreover, both bacteria degraded phenols naturally present or even exogenously added at high concentrations in effluents from the chemical industry and a tannery in short time (up to 5 d). In addition, a significant reduction of biological oxygen demand and chemical oxygen demand values was achieved after 7 d of treatment for both effluents using Acinetobacter sp. RTE 1.4 and Rhodococcus sp. CS1, respectively. These results showed that Acinetobacter sp. RTE1.4 and Rhodococcus sp. CS 1 might be considered as useful biotechnological tools for an efficient treatment of different effluents, since they showed wide versatility to detoxify these complex matrices, even supplemented with high phenol concentrations.

Polyelectrolyte Complexes of a Cationic All Conjugated Fluorene Thiophene Diblock Copolymer with Aqueous DNA

DEFF Research Database (Denmark)

Knaapila, Matti; Costa, Telma; Garamus, Vasil M.

2015-01-01

TMAHT repeat units; x = 0.5 equals the nominal charge neutralization. PF2/6-P3TMAHT forms 20–40 nm sized particles with PF2/6 core and hydrated P3TMAHT exterior. The polymer particles form loose one-dimensional chains giving micrometer long branched chains (0.19 ≤ x ≤ 0.76) and subsequently randomly......We report on the structural and colorimetric effects of interaction of aqueous ∼0.06–1% poly[9,9-bis(2-ethylhexyl)fluorene]-b-poly[3-6-trimethylammoniumhexyl)thiophene] bromide (PF2/6-P3TMAHT) with double-stranded DNA to form PF2/6-P3TMAHT(DNA)x where x is the molar ratio of DNA base pairs to P3...

Destruction of acenaphthene, fluorene, anthracene and pyrene by a dc gliding arc plasma reactor.

Science.gov (United States)

Yu, Liang; Tu, Xin; Li, Xiaodong; Wang, Yu; Chi, Yong; Yan, Jianhua

2010-08-15

In this study, four kinds of PAHs (polycyclic aromatic hydrocarbons) i.e. acenaphthene, fluorene, anthracene and pyrene are used as targets for investigation of PAHs treatment process assisted by dc gliding arc discharge. The effects of carrier gas and external resistance on the PAHs decomposition process are discussed. The results indicate that the destruction rate can be achieved to the highest with the carrier gas of oxygen and the external resistance of 50 kOmega independent of type of PAHs. Furthermore, experimental results suggest that destruction energy efficiency of gliding arc plasma would be improved by treating higher concentration pollutants. Based on the analysis of experimental results, possible destruction mechanisms in different gas discharge are discussed. Copyright 2010 Elsevier B.V. All rights reserved.

Modulated charge injection in p-type dye-sensitized solar cells using fluorene-based light absorbers.

Science.gov (United States)

Liu, Zonghao; Xiong, Dehua; Xu, Xiaobao; Arooj, Qudsia; Wang, Huan; Yin, Liyuan; Li, Wenhui; Wu, Huaizhi; Zhao, Zhixin; Chen, Wei; Wang, Mingkui; Wang, Feng; Cheng, Yi-Bing; He, Hongshan

2014-03-12

In this study, new pull-push arylamine-fluorene based organic dyes zzx-op1, zzx-op2, and zzx-op3 have been designed and synthesized for p-type dye-sensitized solar cells (p-DSCs). In zzx-op1, a di(p-carboxyphenyl)amine (DCPA) was used as an electron donor, a perylenemonoimide (PMID) as an electron acceptor, and a fluorene (FLU) unit with two aliphatic hexyl chains as a π-conjugated linker. In zzx-op2 and zzx-op3, a 3,4-ethylenedioxythiophene (EDOT) and a thiophene were inserted consecutively between PMID and FLU to tune the energy levels of the frontier molecular orbitals of the dyes. The structural modification broadened the spectral coverage from an onset of 700 nm for zzx-op1 to 750 nm for zzx-op3. The electron-rich EDOT and thiophene lifted up the HOMO (highest occupied molecular orbital) levels of zzx-op2 and zzx-op3, making their potential more negative than zzx-op1. When three dyes were employed in p-type DSCs with I(-)/I3(-) as a redox couple and NiO nanoparticles as hole materials, zzx-op1 exhibited impressive energy conversion efficiency of 0.184% with the open-circuit voltage (VOC) of 112 mV and the short-circuit current density (JSC) of 4.36 mA cm(-2) under AM 1.5G condition. Density functional theory calculations, transient photovoltage decay measurements, and electrochemical impedance spectroscopic studies revealed that zzx-op1 sensitized solar cell exhibited much higher charge injection efficiency (90.3%) than zzx-op2 (53.9%) and zzx-op3 (39.0%), indicating a trade-off between spectral broadening and electron injection driving force in p-type DSCs.

Influence of growth medium on cometabolic degradation of polycyclic aromatic hydrocarbons by Sphingomonas sp. strain PheB4

Energy Technology Data Exchange (ETDEWEB)

Zhong Yin; Wang Xiaowei [Sun Yat-Sen Univ., Guangzhou (China). State Key Lab. of Biocontrol; Futian-CityU Mangrove Research and Development Centre, Shenzhen (China). Futian National Nature Reserve; Luan Tiangang; Lan Chongyu [Sun Yat-Sen Univ., Guangzhou (China). State Key Lab. of Biocontrol; Tam, N.F.Y. [Futian-CityU Mangrove Research and Development Centre, Shenzhen (China). Futian National Nature Reserve; City Univ. of Hong Kong, Kowloon (China). Dept. of Biology and Chemistry

2007-05-15

The influence of growth medium on cometabolic degradation of polycyclic aromatic hydrocarbons (PAHs) was investigated when Sphingomonas sp. strain PheB4 isolated from surface mangrove sediments was grown in either phenanthrene-containing mineral salts medium (PMSM) or nutrient broth (NB). The NB-grown culture exhibited a more rapid cometabolic degradation of single and mixed non-growth substrate PAHs compared to the PMSM-grown culture. The concentrations of PAH metabolites were also lower in NB-grown culture than in PMSM-grown culture, suggesting that NB-grown culture removed metabolites at a faster rate, particularly, for metabolites produced from cometabolic degradation of a binary mixture of PAHs. Cometabolic pathways of single PAH (anthracene, fluorene, or fluoranthene) in NB-grown culture showed similarity to that in PMSM-grown culture. However, cometabolic pathways of mixed PAHs were more diverse in NB-grown culture than that in PMSM-grown culture. These results indicated that nutrient rich medium was effective in enhancing cometabolic degradation of mixed PAHs concomitant with a rapid removal of metabolites, which could be useful for the bioremediation of mixed PAHs contaminated sites using Sphingomonas sp. strain PheB4. (orig.)

Theoretical investigations on fluorene-pyridines as electroactive sensor molecules

International Nuclear Information System (INIS)

Horner, S.; Romaner, L.; Zojer, E.; Kappaun, S.; Slugovc, C.; Kelterer, A.-M.

2006-01-01

Full text: Organic semiconducting oligomers and polymers are promising candidates for chemical sensing applications. In this work, sensor molecules comprising a sequence of para- and meta-linked fluorene- and pyridine- units are studied. Spectroscopic investigations show that upon protonation of the pyridine rings (i.e., when adding acids to the solutions), one observes a distinct red-shift of the absorption and emission maxima by approximately 0.5 eV. The fact that the polymers are highly emissive in both, the non protonated as well as protonated state makes them particularly interesting candidates for ratio metric sensors based on organic semiconductors. To rationalize the observed behaviour, we calculate the geometric and electronic structures of the relevant molecules at various stages of protonation using both semiempirical as well as density functional theory based methods. In general, we obtain good agreement between theory and experiment and excited state localization is found to play a crucial role in the sensing process. In practice, one can expect the interaction between the proton and the nitrogen of the pyridine unit to be modulated by interaction with the counter-ion as well as by screening through solvent molecules. These effects are accounted for in calculations on smaller model systems. (author)

Ternary thiophene-X-thiophene semiconductor building blocks (X = fluorene, carbazole, phenothiazine): Modulating electronic properties and electropolymerization ability by tuning the X core

Energy Technology Data Exchange (ETDEWEB)

Tacca, Alessandra, E-mail: alessandra.tacca@eni.com [Centro Ricerche per le Energie non Convenzionali, Istituto ENI Donegani, ENI S.p.A., Via G. Fauser 4, 28100 Novara (Italy); Po, Riccardo; Caldararo, Maria; Chiaberge, Stefano; Gila, Liliana; Longo, Luca [Centro Ricerche per le Energie non Convenzionali, Istituto ENI Donegani, ENI S.p.A., Via G. Fauser 4, 28100 Novara (Italy); Mussini, Patrizia Romana [Dipartimento di Chimica Fisica ed Elettrochimica, Universita degli Studi di Milano, Via Golgi 19, 20133 Milano (Italy); Pellegrino, Andrea; Perin, Nicola; Salvalaggio, Mario; Savoini, Alberto; Spera, Silvia [Centro Ricerche per le Energie non Convenzionali, Istituto ENI Donegani, ENI S.p.A., Via G. Fauser 4, 28100 Novara (Italy)

2011-07-30

Highlights: > Effect of aromatic core on electronic properties in thiophene-X-thiophene trimers. > The lower the electron richness of X core, the deeper the HOMO level. > Different thiophene positions on X lead to kinked structure with lower conjugation. > The fluorene structure exhibits the lowest Stokes shift and the highest quantum yield. > The corresponding polymers obtained through three routes were studied. - Abstract: To achieve rationalization criteria for target-oriented molecular design of Th-X-Th (Th = thiophene) semiconductor building blocks, we have carried out an extensive investigation on the effects of the X core (X = fluorene, carbazole or phenothiazine) on the electronic properties and polymerization ability of Th-X-Th monomers and on the electronic and structural properties of the corresponding periodic conducting polymers -(Th-X-Th){sub n}-, obtained by electropolymerization and, for comparison's sake, by FeCl{sub 3}-catalyzed polymerization and/or Suzuki coupling. The effects of molecule bending and of solubilising bulky alkyl substituents have also been considered. The systematic, exhaustive template sequence combined with a rigorous, multitechnique investigation protocol affords a unique data library and a complete set of reliable interpretative/predictive guidelines.

Presence of bacterial DNA and bacterial peptidoglycans in joints of patients with rheumatoid arthritis and other arthritides

NARCIS (Netherlands)

van der Heijden, I. M.; Wilbrink, B.; Tchetverikov, I.; Schrijver, I. A.; Schouls, L. M.; Hazenberg, M. P.; Breedveld, F. C.; Tak, P. P.

2000-01-01

The continuous presence of bacteria or their degraded antigens in the synovium may be involved in the pathogenesis of rheumatoid arthritis (RA). The aim of this study was to determine the presence of bacterial nucleic acids and bacterial cell wall constituents in the joints of patients with RA and

Isolation and characterization of diuron-degrading bacteria from lotic surface water.

Science.gov (United States)

Batisson, Isabelle; Pesce, Stéphane; Besse-Hoggan, Pascale; Sancelme, Martine; Bohatier, Jacques

2007-11-01

The bacterial community structure of a diuron-degrading enrichment culture from lotic surface water samples was analyzed and the diuron-degrading strains were selected using a series of techniques combining temporal temperature gradient gel electrophoresis (TTGE) of 16 S rDNA gene V1-V3 variable regions, isolation of strains on agar plates, colony hybridization methods, and biodegradation assays. The TTGE fingerprints revealed that diuron had a strong impact on bacterial community structure and highlighted both diuron-sensitive and diuron-adapted bacterial strains. Two bacterial strains, designated IB78 and IB93 and identified as belonging to Pseudomonas sp. and Stenotrophomonas sp., were isolated and shown to degrade diuron in pure resting cells in a first-order kinetic reaction during the first 24 h of incubation with no 3,4-DCA detected. The percentages of degradation varied from 25% to 60% for IB78 and 20% to 65% for IB93 and for a diuron concentration range from 20 mg/L to 2 mg/L, respectively. It is interesting to note that diuron was less degraded by single isolates than by mixed resting cells, thereby underlining a cumulative effect between these two strains. To the best of our knowledge, this is the first report of diuron-degrading strains isolated from lotic surface water.

Bacterial Community Dynamics in Dichloromethane-Contaminated Groundwater Undergoing Natural Attenuation

Directory of Open Access Journals (Sweden)

Justin Wright

2017-11-01

Full Text Available The uncontrolled release of the industrial solvent methylene chloride, also known as dichloromethane (DCM, has resulted in widespread groundwater contamination in the United States. Here we investigate the role of groundwater bacterial communities in the natural attenuation of DCM at an undisclosed manufacturing site in New Jersey. This study investigates the bacterial community structure of groundwater samples differentially contaminated with DCM to better understand the biodegradation potential of these autochthonous bacterial communities. Bacterial community analysis was completed using high-throughput sequencing of the 16S rRNA gene of groundwater samples (n = 26 with DCM contamination ranging from 0.89 to 9,800,000 μg/L. Significant DCM concentration-driven shifts in overall bacterial community structure were identified between samples, including an increase in the abundance of Firmicutes within the most contaminated samples. Across all samples, a total of 6,134 unique operational taxonomic units (OTUs were identified, with 16 taxa having strong correlations with increased DCM concentration. Putative DCM degraders such as Pseudomonas, Dehalobacterium and Desulfovibrio were present within groundwater across all levels of DCM contamination. Interestingly, each of these taxa dominated specific DCM contamination ranges respectively. Potential DCM degrading lineages yet to be cited specifically as a DCM degrading organisms, such as the Desulfosporosinus, thrived within the most heavily contaminated groundwater samples. Co-occurrence network analysis revealed aerobic and anaerobic bacterial taxa with DCM-degrading potential were present at the study site. Our 16S rRNA gene survey serves as the first in situ bacterial community assessment of contaminated groundwater harboring DCM concentrations ranging over seven orders of magnitude. Diversity analyses revealed known as well as potentially novel DCM degrading taxa within defined DCM concentration

Autophagy and bacterial clearance: a not so clear picture

OpenAIRE

Mostowy, Serge

2012-01-01

Autophagy, an intracellular degradation process highly conserved from yeast to humans, is viewed as an important defence mechanism to clear intracellular bacteria. However, recent work has shown that autophagy may have different roles during different bacterial infections that restrict bacterial replication (antibacterial autophagy), act in cell autonomous signalling (non-bacterial autophagy) or support bacterial replication (pro-bacterial autophagy). This review will focus on newfound intera...

Combined use of alkane-degrading and plant growth-promoting bacteria enhanced phytoremediation of diesel contaminated soil.

Science.gov (United States)

Tara, Nain; Afzal, Muhammad; Ansari, Tariq M; Tahseen, Razia; Iqbal, Samina; Khan, Qaiser M

2014-01-01

Inoculation of plants with pollutant-degrading and plant growth-promoting microorganisms is a simple strategy to enhance phytoremediation activity. The objective of this study was to determine the effect of inoculation of different bacterial strains, possessing alkane-degradation and 1-amino-cyclopropane-1 -carboxylic acid (ACC) deaminase activity, on plant growth and phytoremediation activity. Carpet grass (Axonopus affinis) was planted in soil spiked with diesel (1% w/w) for 90 days and inoculated with different bacterial strains, Pseudomonas sp. ITRH25, Pantoea sp. BTRH79 and Burkholderia sp. PsJN, individually and in combination. Generally, bacterial application increased total numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere ofcarpet grass, plant biomass production, hydrocarbon degradation and reduced genotoxicity. Bacterial strains possessing different beneficial traits affect plant growth and phytoremediation activity in different ways. Maximum bacterial population, plant biomass production and hydrocarbon degradation were achieved when carpet grass was inoculated with a consortium of three strains. Enhanced plant biomass production and hydrocarbon degradation were associated with increased numbers of culturable hydrocarbon-degrading bacteria in the rhizosphere of carpet grass. The present study revealed that the combined use of different bacterial strains, exhibiting different beneficial traits, is a highly effective strategy to improve plant growth and phytoremediation activity.

Exciplex elimination in an organic light-emitting diode based on a fluorene derivative by inserting 4,4'-N,N'-dicarbazole-biphenylinto donor/acceptor interface

International Nuclear Information System (INIS)

Wei, Zhang; Jun-Sheng, Yu; Jiang, Huang; Ya-Dong, Jiang; Qing, Zhang; Kang-Li, Cao

2010-01-01

Organic light-emitting diodes (OLEDs) composed of a novel fluorene derivative of 2,3-bis(9,9-dihexyl-9H-fluoren-2-yl)-6,7-difluoroquinoxaline (F2Py) were fabricated, and exciplex emission was observed in the device. To depress the exciplex in an OLED for pure colour light emission, 4, 4'-N,N'-dicarbazole-biphenyl (CBP) was inserted as a separator at the donor/acceptor interface. It was found that the device without the CBP layer emitted a green light peaking at 542 nm from the exciplex and a shoulder peak about 430 nm from F2Py. In contrast, the OLED with CBP layer emitted only a blue light peak at about 432 nm from F2Py. Device efficiencies were calculated by a simulative mode in an injection controlled type mechanism, and the results showed that exciplexes yield much lower quantum efficiency than excitons. The device with CBP has a higher power efficiency as no exciplex was present. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Evaluation of effectiveness of bacterial product which can degrade pesticide-dimethoate on the scale of true practice test

International Nuclear Information System (INIS)

Pham Thi Le Ha; Tran Thi Thuy; Le Hai; Nguyen Duy Hang; Vo Thi Thu Ha; Nguyen Tuong Ly Lan; Le Tat Mua; Tran Kim Duyen; Mai Hoang Lam

2004-01-01

Dimethoate, an organophosphate pesticide has been widely used in Dalat, Lamdong. It is much toxic to birds, human being and other mammals. Its widespread use has caused environmental concern on the basic of frequent detection of dimethoate in soil and water. Microorganisms are key agents in the degradation of waste, oil and a vast array of organic pesticide in terrestrial and aquatic ecosystems. In previous study, bacteria products which can degrade. Dimethoate were produced. The present study was designed to evaluate the effectiveness of bacterial product which can degrade Pesticide-Dimethoate on the scale of true practice test. The results indicated that application bacteria product to soil grown with Cauliflower and Chinese Cabbage sprayed with organic phosphorus pesticides (Dimethoate and Chloropyrifos), the pesticide residues in soil, water and vegetables were as follow: The residues of Dimethoate and Chloropyrifos in soil grown with Cauliflower, Chinese cabbages are different. They concentrated mostly in the surface litter and top soil layers with the depth from 0 to 20 cm. From the depth of 20 cm to 100 cm, the pesticide residues were ignorable. Residue of Chloropyrifos in soil was small as well. Dimethoate residues in soil grown with Cauliflower were higher than that of Chinese cabbages. On the basis of the environmental criteria of Ministry for Science, Technology and Environment (6/95), Dimethoate residues in soil grown with cauliflowers were in excess of the maximum limit. In the case of using bacteria product to soil, pesticide residues in soil were decreased. The results also indicated that Chloropyrifos residues in water (water obtained at the depth of 75 cm and 100 cm by days) were small. Residue of Dimethoate in water small. Residue of Dimethoate in water obtained from the Cauliflower bed were higher than of Chinese cabbages one. Using bacteria product to soil, pesticide residues in water decreased. On the basis of the environmental criteria of

Soil bacterial and fungal community successions under the stress of chlorpyrifos application and molecular characterization of chlorpyrifos-degrading isolates using ERIC-PCR*

Science.gov (United States)

Chen, Lie-zhong; Li, Yan-li; Yu, Yun-long

2014-01-01

Chlorpyrifos is a widely used insecticide in recent years, and it will produce adverse effects on soil when applied on crops or mixed with soil. In this study, nested polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) were combined to explore the bacterial and fungal community successions in soil treated with 5 and 20 mg/kg of chlorpyrifos. Furthermore, isolates capable of efficiently decomposing chlorpyrifos were molecular-typed using enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR). Under the experimental conditions, degradation of chlorpyrifos in soil was interpreted with the first-order kinetics, and the half-lives of chlorpyrifos at 5 and 20 mg/kg doses were calculated to be 8.25 and 8.29 d, respectively. DGGE fingerprint and principal component analysis (PCA) indicated that the composition of the fungal community was obviously changed with the chlorpyrifos treatment, and that samples of chlorpyrifos treatment were significantly separated from those of the control from the beginning to the end. While for the bacterial community, chlorpyrifos-treated soil samples were apparently different in the first 30 d and recovered to a similar level of the control up until 60 d, and the distance in the PCA between the chlorpyrifos-treated samples and the control was getting shorter through time and was finally clustered into one group. Together, our results demonstrated that the application of chlorpyrifos could affect the fungal community structure in a quick and lasting way, while only affecting the bacterial community in a temporary way. Finally, nine typical ERIC types of chlorpyrifos-degrading isolates were screened. PMID:24711353

Simple and versatile turbidimetric monitoring of bacterial growth in liquid cultures using a customized 3D printed culture tube holder and a miniaturized spectrophotometer: application to facultative and strictly anaerobic bacteria

Directory of Open Access Journals (Sweden)

Margarida R. G. Maia

2016-08-01

Full Text Available Here we introduce a novel strategy for turbidimetric monitoring of bacterial growth in liquid culture. The instrumentation comprises a light source, a customized 3D printed culture tube holder and a miniaturized spectrophotometer, connected through optical cables. Due to its small footprint and the possibility to operate with external light, bacterial growth was directly monitored from culture tubes in a simple and versatile fashion. This new portable measurement technique was used to monitor the growth of facultative (Escherichia coli ATCC/25922, and Staphylococcus aureus ATCC/29213 and strictly (Butyrivibrio fibrisolvens JW11, Butyrivibrio proteoclasticus P18, and Propionibacterium acnes DSMZ 1897 anaerobic bacteria. For E. coli and S. aureus, the growth rates calculated from normalized optical density values were compared with those ones obtained using a benchtop spectrophotometer without significant differences (P = 0.256. For the strictly anaerobic species, a high precision (RSD < 3.5% was observed between replicates up to 48 h. Regarding its potential for customization, this manifold could accommodate further developments for customized turbidimetric monitoring, such as the use of light-emitting diodes as a light source or flow cells.

Simple and Versatile Turbidimetric Monitoring of Bacterial Growth in Liquid Cultures Using a Customized 3D Printed Culture Tube Holder and a Miniaturized Spectrophotometer: Application to Facultative and Strictly Anaerobic Bacteria.

Science.gov (United States)

Maia, Margarida R G; Marques, Sara; Cabrita, Ana R J; Wallace, R John; Thompson, Gertrude; Fonseca, António J M; Oliveira, Hugo M

2016-01-01

Here we introduce a novel strategy for turbidimetric monitoring of bacterial growth in liquid culture. The instrumentation comprises a light source, a customized 3D printed culture tube holder and a miniaturized spectrophotometer, connected through optical cables. Due to its small footprint and the possibility to operate with external light, bacterial growth was directly monitored from culture tubes in a simple and versatile fashion. This new portable measurement technique was used to monitor the growth of facultative (Escherichia coli ATCC/25922, and Staphylococcus aureus ATCC/29213) and strictly (Butyrivibrio fibrisolvens JW11, Butyrivibrio proteoclasticus P18, and Propionibacterium acnes DSMZ 1897) anaerobic bacteria. For E. coli and S. aureus, the growth rates calculated from normalized optical density values were compared with those ones obtained using a benchtop spectrophotometer without significant differences (P = 0.256). For the strictly anaerobic species, a high precision (relative standard deviation < 3.5%) was observed between replicates up to 48 h. Regarding its potential for customization, this manifold could accommodate further developments for customized turbidimetric monitoring, such as the use of light-emitting diodes as a light source or flow cells.

Effects of forest management practices in temperate beech forests on bacterial and fungal communities involved in leaf litter degradation.

Science.gov (United States)

Purahong, Witoon; Kapturska, Danuta; Pecyna, Marek J; Jariyavidyanont, Katalee; Kaunzner, Jennifer; Juncheed, Kantida; Uengwetwanit, Tanaporn; Rudloff, Renate; Schulz, Elke; Hofrichter, Martin; Schloter, Michael; Krüger, Dirk; Buscot, François

2015-05-01

Forest management practices (FMPs) significantly influence important ecological processes and services in Central European forests, such as leaf litter decomposition and nutrient cycling. Changes in leaf litter diversity, and thus, its quality as well as microbial community structure and function induced by different FMPs were hypothesized to be the main drivers causing shifts in decomposition rates and nutrient release in managed forests. In a litterbag experiment lasting 473 days, we aimed to investigate the effects of FMPs (even-aged timber management, selective logging and unmanaged) on bacterial and fungal communities involved in leaf litter degradation over time. Our results showed that microbial communities in leaf litter were strongly influenced by both FMPs and sampling date. The results from nonmetric multidimensional scaling (NMDS) ordination revealed distinct patterns of bacterial and fungal successions over time in leaf litter. We demonstrated that FMPs and sampling dates can influence a range of factors, including leaf litter quality, microbial macronutrients, and pH, which significantly correlate with microbial community successions.

Ultrasound-assisted degradation of a new bacterial ...

African Journals Online (AJOL)

user

2012-05-14

May 14, 2012 ... polysaccharide composed of rhamnose, glucose, mannose, galactose and glucuronic acid in the molar ... distinguish it from thermal or photochemical degradation ..... hydrolysis with dilute acid cleaves the glycosidic bonds in.

Two-dimensional flow-through microcosms - Versatile test systems to study biodegradation processes in porous aquifers

Science.gov (United States)

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

2009-05-01

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

Genomic analysis reveals versatile heterotrophic capacity of a potentially symbiotic sulfur-oxidizing bacterium in sponge

KAUST Repository

Tian, Renmao

2014-08-29

Sulfur-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) play essential roles in marine sponges. However, the detailed characteristics and physiology of the bacteria are largely unknown. Here, we present and analyse the first genome of sponge-associated SOB using a recently developed metagenomic binning strategy. The loss of transposase and virulence-associated genes and the maintenance of the ancient polyphosphate glucokinase gene suggested a stabilized SOB genome that might have coevolved with the ancient host during establishment of their association. Exclusive distribution in sponge, bacterial detoxification for the host (sulfide oxidation) and the enrichment for symbiotic characteristics (genes-encoding ankyrin) in the SOB genome supported the bacterial role as an intercellular symbiont. Despite possessing complete autotrophic sulfur oxidation pathways, the bacterium developed a much more versatile capacity for carbohydrate uptake and metabolism, in comparison with its closest relatives (Thioalkalivibrio) and to other representative autotrophs from the same order (Chromatiales). The ability to perform both autotrophic and heterotrophic metabolism likely results from the unstable supply of reduced sulfur in the sponge and is considered critical for the sponge-SOB consortium. Our study provides insights into SOB of sponge-specific clade with thioautotrophic and versatile heterotrophic metabolism relevant to its roles in the micro-environment of the sponge body. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Diversity of bacterial dimethylsulfoniopropionate degradation genes in surface seawater of Arctic Kongsfjorden.

Science.gov (United States)

Zeng, Yin-Xin; Qiao, Zong-Yun; Yu, Yong; Li, Hui-Rong; Luo, Wei

2016-09-08

Dimethylsulfoniopropionate (DMSP), which is the major source of organic sulfur in the world's oceans, plays a significant role in the global sulfur cycle. This compound is rapidly degraded by marine bacteria either by cleavage to dimethylsulfide (DMS) or demethylation to 3-methylmercaptopropionate (MMPA). The diversity of genes encoding bacterial demethylation (dmdA) and DMS production (dddL and dddP) were measured in Arctic Kongsfjorden. Both dmdA and dddL genes were detected in all stations along a transect from the outer to the inner fjord, while dddP gene was only found in the outer and middle parts of the fjord. The dmdA gene was completely confined to the Roseobacter clade, while the dddL gene was confined to the genus Sulfitobacter. Although the dddP gene pool was also dominated by homologs from the Roseobacter clade, there were a few dddP genes showing close relationships to both Alphaproteobacter and Gammaproteobacter. The results of this study suggest that the Roseobacter clade may play an important role in DMSP catabolism via both demethylation and cleavage pathways in surface waters of Kongsfjorden during summer.

Degradation and depolymerization of plastic waste by local bacterial isolates and bubble column reactor

Science.gov (United States)

Hussein, Amal A.; Alzuhairi, Mohammed; Aljanabi, Noor H.

2018-05-01

Accumulation of plastics, especially Polyethylene terephthalate (PET), is an ever increasing ecological threat due to its excessive usage in everyday human life. Nowadays, there are many methods to get rid of plastic wastes including burning, recycling and burying. However, these methods are not very active since their long period, anaerobic conditions that increase the rate of toxic materials released into the environment. This work aims to study the biological degradation of PET microorganism isolated from soil sample. Thirty eight (38) bacterial isolates were isolated from ten soil and plastic waste sample collected from four different waste disposal sites in Baghdad city during different periods between December 2016 and March 2017. Isolation was performed using enrichment culture method (flasks method) by culturing the soil samples in flasks with MSM medium where there is no carbon source only PET. Results showed that Al-Za'farania sample gave a higher number of isolates (13 isolates), while other samples gave less number of isolates. Screening was performed depending on their ability to grow in liquid MSM which contains PET powder and pieces and change the color of the PET-emulsified liquid medium as well as their ability to form the clear zone on PET-MSM agar. The results showed that NH-D-1 isolate has the higher ability to degrade DPET and PET pieces. According to morphological, biochemical characterization and Vitek-2 technique, the most active isolate was identified as Acinetobacter baumannii.

Functional diversity of bacterial genes associated with aromatic hydrocarbon degradation in anthropogenic dark earth of Amazonia

Directory of Open Access Journals (Sweden)

Mariana Gomes Germano

2012-05-01

Full Text Available The objective of this work was to evaluate the catabolic gene diversity for the bacterial degradation of aromatic hydrocarbons in anthropogenic dark earth of Amazonia (ADE and their biochar (BC. Functional diversity analyses in ADE soils can provide information on how adaptive microorganisms may influence the fertility of soils and what is their involvement in biogeochemical cycles. For this, clone libraries containing the gene encoding for the alpha subunit of aromatic ring-hydroxylating dioxygenases (α-ARHD bacterial gene were constructed, totaling 800 clones. These libraries were prepared from samples of an ADE soil under two different land uses, located at the Caldeirão Experimental Station - secondary forest (SF and agriculture (AG -, and the biochar (SF_BC and AG_BC, respectively. Heterogeneity estimates indicated greater diversity in BC libraries; and Venn diagrams showed more unique operational protein clusters (OPC in the SF_BC library than the ADE soil, which indicates that specific metabolic processes may occur in biochar. Phylogenetic analysis showed unidentified dioxygenases in ADE soils. Libraries containing functional gene encoding for the alpha subunit of the aromatic ring-hydroxylating dioxygenases (ARHD gene from biochar show higher diversity indices than those of ADE under secondary forest and agriculture.

Exploring the microbiota dynamics related to vegetable biomasses degradation and study of lignocellulose-degrading bacteria for industrial biotechnological application

Science.gov (United States)

Ventorino, Valeria; Aliberti, Alberto; Faraco, Vincenza; Robertiello, Alessandro; Giacobbe, Simona; Ercolini, Danilo; Amore, Antonella; Fagnano, Massimo; Pepe, Olimpia

2015-02-01

The aims of this study were to evaluate the microbial diversity of different lignocellulosic biomasses during degradation under natural conditions and to isolate, select, characterise new well-adapted bacterial strains to detect potentially improved enzyme-producing bacteria. The microbiota of biomass piles of Arundo donax, Eucalyptus camaldulensis and Populus nigra were evaluated by high-throughput sequencing. A highly complex bacterial community was found, composed of ubiquitous bacteria, with the highest representation by the Actinobacteria, Proteobacteria, Bacteroidetes and Firmicutes phyla. The abundances of the major and minor taxa retrieved during the process were determined by the selective pressure produced by the lignocellulosic plant species and degradation conditions. Moreover, cellulolytic bacteria were isolated using differential substrates and screened for cellulase, cellobiase, xylanase, pectinase and ligninase activities. Forty strains that showed multienzymatic activity were selected and identified. The highest endo-cellulase activity was seen in Promicromonospora sukumoe CE86 and Isoptericola variabilis CA84, which were able to degrade cellulose, cellobiose and xylan. Sixty-two percent of bacterial strains tested exhibited high extracellular endo-1,4-ß-glucanase activity in liquid media. These approaches show that the microbiota of lignocellulosic biomasses can be considered an important source of bacterial strains to upgrade the feasibility of lignocellulose conversion for the `greener' technology of second-generation biofuels.

Degradation of Polyester Polyurethane by Bacterial Polyester Hydrolases

Directory of Open Access Journals (Sweden)

Juliane Schmidt

2017-02-01

Full Text Available Polyurethanes (PU are widely used synthetic polymers. The growing amount of PU used industrially has resulted in a worldwide increase of plastic wastes. The related environmental pollution as well as the limited availability of the raw materials based on petrochemicals requires novel solutions for their efficient degradation and recycling. The degradation of the polyester PU Impranil DLN by the polyester hydrolases LC cutinase (LCC, TfCut2, Tcur1278 and Tcur0390 was analyzed using a turbidimetric assay. The highest hydrolysis rates were obtained with TfCut2 and Tcur0390. TfCut2 also showed a significantly higher substrate affinity for Impranil DLN than the other three enzymes, indicated by a higher adsorption constant K. Significant weight losses of the solid thermoplastic polyester PU (TPU Elastollan B85A-10 and C85A-10 were detected as a result of the enzymatic degradation by all four polyester hydrolases. Within a reaction time of 200 h at 70 °C, LCC caused weight losses of up to 4.9% and 4.1% of Elastollan B85A-10 and C85A-10, respectively. Gel permeation chromatography confirmed a preferential degradation of the larger polymer chains. Scanning electron microscopy revealed cracks at the surface of the TPU cubes as a result of enzymatic surface erosion. Analysis by Fourier transform infrared spectroscopy indicated that the observed weight losses were a result of the cleavage of ester bonds of the polyester TPU.

Deciphering Cyanide-Degrading Potential of Bacterial Community Associated with the Coking Wastewater Treatment Plant with a Novel Draft Genome.

Science.gov (United States)

Wang, Zhiping; Liu, Lili; Guo, Feng; Zhang, Tong

2015-10-01

Biotreatment processes fed with coking wastewater often encounter insufficient removal of pollutants, such as ammonia, phenols, and polycyclic aromatic hydrocarbons (PAHs), especially for cyanides. However, only a limited number of bacterial species in pure cultures have been confirmed to metabolize cyanides, which hinders the improvement of these processes. In this study, a microbial community of activated sludge enriched in a coking wastewater treatment plant was analyzed using 454 pyrosequencing and Illumina sequencing to characterize the potential cyanide-degrading bacteria. According to the classification of these pyro-tags, targeting V3/V4 regions of 16S rRNA gene, half of them were assigned to the family Xanthomonadaceae, implying that Xanthomonadaceae bacteria are well-adapted to coking wastewater. A nearly complete draft genome of the dominant bacterium was reconstructed from metagenome of this community to explore cyanide metabolism based on analysis of the genome. The assembled 16S rRNA gene from this draft genome showed that this bacterium was a novel species of Thermomonas within Xanthomonadaceae, which was further verified by comparative genomics. The annotation using KEGG and Pfam identified genes related to cyanide metabolism, including genes responsible for the iron-harvesting system, cyanide-insensitive terminal oxidase, cyanide hydrolase/nitrilase, and thiosulfate:cyanide transferase. Phylogenetic analysis showed that these genes had homologs in previously identified genomes of bacteria within Xanthomonadaceae and even presented similar gene cassettes, thus implying an inherent cyanide-decomposing potential. The findings of this study expand our knowledge about the bacterial degradation of cyanide compounds and will be helpful in the remediation of cyanides contamination.

Characterization of Biosurfactant Produced during Degradation of Hydrocarbons Using Crude Oil As Sole Source of Carbon.

Science.gov (United States)

Patowary, Kaustuvmani; Patowary, Rupshikha; Kalita, Mohan C; Deka, Suresh

2017-01-01

Production and spillage of petroleum hydrocarbons which is the most versatile energy resource causes disastrous environmental pollution. Elevated oil degrading performance from microorganisms is demanded for successful microbial remediation of those toxic pollutants. The employment of biosurfactant-producing and hydrocarbon-utilizing microbes enhances the effectiveness of bioremediation as biosurfactant plays a key role by making hydrocarbons bio-available for degradation. The present study aimed the isolation of a potent biosurfactant producing indigenous bacteria which can be employed for crude oil remediation, along with the characterization of the biosurfactant produced during crude oil biodegradation. A potent bacterial strain Pseudomonas aeruginosa PG1 (identified by 16s rDNA sequencing) was isolated from hydrocarbon contaminated soil that could efficiently produce biosurfactant by utilizing crude oil components as the carbon source, thereby leading to the enhanced degradation of the petroleum hydrocarbons. Strain PG1 could degrade 81.8% of total petroleum hydrocarbons (TPH) after 5 weeks of culture when grown in mineral salt media (MSM) supplemented with 2% (v/v) crude oil as the sole carbon source. GCMS analysis of the treated crude oil samples revealed that P. aeruginosa PG1 could potentially degrade various hydrocarbon contents including various PAHs present in the crude oil. Biosurfactant produced by strain PG1 in the course of crude oil degradation, promotes the reduction of surface tension (ST) of the culture medium from 51.8 to 29.6 mN m -1 , with the critical micelle concentration (CMC) of 56 mg L -1 . FTIR, LC-MS, and SEM-EDS studies revealed that the biosurfactant is a rhamnolipid comprising of both mono and di rhamnolipid congeners. The biosurfactant did not exhibit any cytotoxic effect to mouse L292 fibroblastic cell line, however, strong antibiotic activity against some pathogenic bacteria and fungus was observed.

Characterization of Biosurfactant Produced during Degradation of Hydrocarbons Using Crude Oil As Sole Source of Carbon

Science.gov (United States)

Patowary, Kaustuvmani; Patowary, Rupshikha; Kalita, Mohan C.; Deka, Suresh

2017-01-01

Production and spillage of petroleum hydrocarbons which is the most versatile energy resource causes disastrous environmental pollution. Elevated oil degrading performance from microorganisms is demanded for successful microbial remediation of those toxic pollutants. The employment of biosurfactant-producing and hydrocarbon-utilizing microbes enhances the effectiveness of bioremediation as biosurfactant plays a key role by making hydrocarbons bio-available for degradation. The present study aimed the isolation of a potent biosurfactant producing indigenous bacteria which can be employed for crude oil remediation, along with the characterization of the biosurfactant produced during crude oil biodegradation. A potent bacterial strain Pseudomonas aeruginosa PG1 (identified by 16s rDNA sequencing) was isolated from hydrocarbon contaminated soil that could efficiently produce biosurfactant by utilizing crude oil components as the carbon source, thereby leading to the enhanced degradation of the petroleum hydrocarbons. Strain PG1 could degrade 81.8% of total petroleum hydrocarbons (TPH) after 5 weeks of culture when grown in mineral salt media (MSM) supplemented with 2% (v/v) crude oil as the sole carbon source. GCMS analysis of the treated crude oil samples revealed that P. aeruginosa PG1 could potentially degrade various hydrocarbon contents including various PAHs present in the crude oil. Biosurfactant produced by strain PG1 in the course of crude oil degradation, promotes the reduction of surface tension (ST) of the culture medium from 51.8 to 29.6 mN m−1, with the critical micelle concentration (CMC) of 56 mg L−1. FTIR, LC-MS, and SEM-EDS studies revealed that the biosurfactant is a rhamnolipid comprising of both mono and di rhamnolipid congeners. The biosurfactant did not exhibit any cytotoxic effect to mouse L292 fibroblastic cell line, however, strong antibiotic activity against some pathogenic bacteria and fungus was observed. PMID:28275373

Evaluation of bacterial surfactant toxicity towards petroleum degrading microorganisms.

Science.gov (United States)

Lima, Tânia M S; Procópio, Lorena C; Brandão, Felipe D; Leão, Bruna A; Tótola, Marcos R; Borges, Arnaldo C

2011-02-01

The acute toxicity of bacterial surfactants LBBMA111A, LBBMA155, LBBMA168, LBBMA191 and LBBMA201 and the synthetic surfactant sodium dodecyl sulfate (SDS) on the bioluminescent bacterium Vibrio fischeri was evaluated by measuring the reduction of light emission (EC(20)) by this microorganism when exposed to different surfactant concentrations. Moreover, the toxic effects of different concentrations of biological and synthetic surfactants on the growth of pure cultures of isolates Acinetobacter baumannii LBBMA04, Acinetobacter junni LBBMA36, Pseudomonas sp. LBBMA101B and Acinetobacter baumanni LBBMAES11 were evaluated in mineral medium supplemented with glucose. The EC(20) values obtained confirmed that the biosurfactants have a significantly lower toxicity to V. fischeri than the SDS. After 30 min of exposure, bacterial luminescence was almost completely inhibited by SDS at a concentration of 4710 mg L(-1). Growth reduction of pure bacterial cultures caused by the addition of biosurfactants to the growth medium was lower than that caused by SDS. Copyright © 2010 Elsevier Ltd. All rights reserved.

Probing living bacterial adhesion by single cell force spectroscopy using atomic force microscopy

DEFF Research Database (Denmark)

Zeng, Guanghong; Ogaki, Ryosuke; Regina, Viduthalai R.

be considered. We have therefore developed a simple and versatile method to make single-cell bacterial probes for measuring single cell adhesion with atomic force microscopy (AFM).[1] A single-cell probe was readily made by picking up a bacterial cell from a glass surface using a tipless AFM cantilever coated...... random immobilization is obtained by submerging the cantilever in a bacterial suspension. The reported method provides a general platform for investigating single cell interactions of bacteria with different surfaces and other cells by AFM force spectroscopy, thus improving our understanding....... The strain-dependent susceptibility to bacterial colonization on conventional PLL-g-PEG illustrates how bacterial diversity challenges development of “universal” antifouling coatings, and AFM single-cell force spectroscopy was proven to be a powerful tool to provide insights into the molecular mechanisms...

Phenotype fingerprinting suggests the involvement of single-genotype consortia in degradation of aromatic compounds by Rhodopseudomonas palustris.

Directory of Open Access Journals (Sweden)

Tatiana V Karpinets

Full Text Available Anaerobic degradation of complex organic compounds by microorganisms is crucial for development of innovative biotechnologies for bioethanol production and for efficient degradation of environmental pollutants. In natural environments, the degradation is usually accomplished by syntrophic consortia comprised of different bacterial species. This strategy allows consortium organisms to reduce efforts required for maintenance of the redox homeostasis at each syntrophic level. Cellular mechanisms that maintain the redox homeostasis during the degradation of aromatic compounds by one organism are not fully understood. Here we present a hypothesis that the metabolically versatile phototrophic bacterium Rhodopseudomonas palustris forms its own syntrophic consortia, when it grows anaerobically on p-coumarate or benzoate as a sole carbon source. We have revealed the consortia from large-scale measurements of mRNA and protein expressions under p-coumarate, benzoate and succinate degrading conditions using a novel computational approach referred as phenotype fingerprinting. In this approach, marker genes for known R. palustris phenotypes are employed to determine the relative expression levels of genes and proteins in aromatics versus non-aromatics degrading condition. Subpopulations of the consortia are inferred from the expression of phenotypes and known metabolic modes of the R. palustris growth. We find that p-coumarate degrading conditions may lead to at least three R. palustris subpopulations utilizing p-coumarate, benzoate, and CO2 and H2. Benzoate degrading conditions may also produce at least three subpopulations utilizing benzoate, CO2 and H2, and N2 and formate. Communication among syntrophs and inter-syntrophic dynamics in each consortium are indicated by up-regulation of transporters and genes involved in the curli formation and chemotaxis. The N2-fixing subpopulation in the benzoate degrading consortium has preferential activation of the

Characterization of a novel oxyfluorfen-degrading bacterial strain Chryseobacterium aquifrigidense and its biochemical degradation pathway.

Science.gov (United States)

Zhao, Huanhuan; Xu, Jun; Dong, Fengshou; Liu, Xingang; Wu, Yanbing; Wu, Xiaohu; Zheng, Yongquan

2016-08-01

Persistent use of the diphenyl ether herbicides oxyfluorfen may seriously increase the health risks and ecological safety problems. A newly bacterium R-21 isolated from active soil was able to degrade and utilize oxyfluorfen as the sole carbon source. R-21 was identified as Chryseobacterium aquifrigidense by morphology, physiobiochemical characteristics, and genetic analysis. Under the optimum cultural conditions (pH 6.9, temperature 33.4 °C, and inoculum size 0.2 g L(-1)), R-21 could degrade 92.1 % of oxyfluorfen at 50 mg L(-1) within 5 days. During oxyfluorfen degradation, six metabolites were detected and identified by atmospheric pressure gas chromatography coupled to quadrupole-time of flight mass spectrometry and ultra-performance liquid chromatography coupled to quadrupole-time of flight mass spectrometry, and a plausible degradation pathway was deduced. Strain R-21 is a promising potential in bioremediation of oxyfluorfen-contaminated environments.

Recognition and repair of 2-aminofluorene- and 2-(acetylamino)fluorene-DNA adducts by UVRABC nuclease

International Nuclear Information System (INIS)

Pierce, J.R.; Case, R.; Tang, Moonshong

1989-01-01

Recognition of damage induced by N-hydroxy-2-aminofluorene (N-OH-AF) and N-acetoxy-2-(acetylamino)fluorene (NAAAF) in both φX174 RFI supercoiled DNA and a linear DNA fragment by purified UVRA, UVRB, and UVRC proteins was investigated. The authors have previously demonstrated that N-OH-AF and NAAAF treatments produce N-(deoxyguanosin-8-yl)-2-aminofluorene (dG-C8-AF) and N-(deoxyguanosin-8-yl)-2-(acetylamino)fluorene (dG-C8-AAF), respectively, in DNA. Using a piperidine cleavage method and DNA sequence analysis, they have found that all guanine residues can be modified by N-OH-AF and NAAAF. These two kinds of adducts have different impacts on the DNA helix structure; while dG-C8-AF maintains the anti configuration, dG-C8-AAF is in the syn form. φX174 RF DNA-Escherichia coli transfection results indicate that while the uvrA, uvrB, and uvrC gene products are needed to repair dG-C8-AAF, the uvrC, but not the uvrA or uvrB gene products, is needed for repair of dG-C8-Af. However, they have found that in vitro the UVRA, UVRB, and UVRC proteins must work in concert to nick both dG-C8-AF and dG-C8-AAF. In general, the reactions of UVRABC nuclease toward dG-C8-AF are similar to those toward dG-C8-AAF; it incises seven to eight nucleotides from the 5' side and three to four nucleotides from the 3' side of the DNA adduct. Evidence is presented to suggest that hydrolysis on the 3' and 5' sides of the damaged base by UVRABC nuclease is not simultaneous and that at least occasionally hydrolysis occurs only on the 3' side or on the 5' side of the damage site. The possible mechanisms of UVRABC nuclease incision for AF-DNA are discussed

Rodlike Supramolecular Nanoassemblies of Degradable Poly(Aspartic Acid) Derivatives and Hydroxyl-Rich Polycations for Effective Delivery of Versatile Tumor-Suppressive ncRNAs.

Science.gov (United States)

Song, Hai-Qing; Pan, Wenting; Li, Rui-Quan; Yu, Bingran; Liu, Wenjuan; Yang, Ming; Xu, Fu-Jian

2018-03-01

The delivery of tumor-suppressive noncoding RNAs (ncRNAs) including short ncRNAs (i.e., miRNAs) and long ncRNAs (lncRNAs) is put forward to treat tumors. In this work, novel rodlike supramolecular nanoassemblies (CNC @CB[8] @ PGEA) of degradable poly(aspartic acid) (PAsp) derivatives-grafted cellulose nanocrystals (CNCs) and hydroxyl-rich polycations (ethanolamine-functionalized poly(glycidyl methacrylate), PGEA) are proposed via typical cucurbit[8]uril (CB[8])-based host-guest interactions for delivery of different ncRNAs to treat hepatocellular carcinoma (HCC). Spindly CNCs, one kind of natural polysaccharide nanoparticles, possess good biocompatibility and unique physico-chemical properties. PGEA with abundant hydroxyl groups is one promising gene carrier with low cytotoxicity. PAsp can benefit the disassembly and degradability of nanoassemblies within cells. CNC @ CB[8]@PGEA combines the different unique properties of CNC, PGEA, and PAsp. CNC @ CB[8] @ PGEA effectively complexes the expression constructs of miR-101 (plasmid pc3.0-miR-101) and lncRNA MEG3 (plasmid pc3.0-MEG3). CNC @ CB[8] @ PGEA produces much better transfection performances than PGEA-containing assembly units. In addition, the codelivery system of CNC @ CB[8] @ PGEA/(pc3.0-MEG3+pc3.0-miR-101) nanocomplexes demonstrates better efficacy in suppressing HCC than CNC @ CB[8] @ PGEA/pc3.0-MEG3 or CNC @ CB[8] @ PGEA/pc3.0-miR-101 nanocomplexes alone. Such rodlike supramolecular nanoassemblies will provide a promising means to produce efficient delivery vectors of versatile tumor-suppressive nucleic acids. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Insights into lignin degradation and its potential industrial applications.

Science.gov (United States)

Abdel-Hamid, Ahmed M; Solbiati, Jose O; Cann, Isaac K O

2013-01-01

Lignocellulose is an abundant biomass that provides an alternative source for the production of renewable fuels and chemicals. The depolymerization of the carbohydrate polymers in lignocellulosic biomass is hindered by lignin, which is recalcitrant to chemical and biological degradation due to its complex chemical structure and linkage heterogeneity. The role of fungi in delignification due to the production of extracellular oxidative enzymes has been studied more extensively than that of bacteria. The two major groups of enzymes that are involved in lignin degradation are heme peroxidases and laccases. Lignin-degrading peroxidases include lignin peroxidase (LiP), manganese peroxidase (MnP), versatile peroxidase (VP), and dye-decolorizing peroxidase (DyP). LiP, MnP, and VP are class II extracellular fungal peroxidases that belong to the plant and microbial peroxidases superfamily. LiPs are strong oxidants with high-redox potential that oxidize the major non-phenolic structures of lignin. MnP is an Mn-dependent enzyme that catalyzes the oxidation of various phenolic substrates but is not capable of oxidizing the more recalcitrant non-phenolic lignin. VP enzymes combine the catalytic activities of both MnP and LiP and are able to oxidize Mn(2+) like MnP, and non-phenolic compounds like LiP. DyPs occur in both fungi and bacteria and are members of a new superfamily of heme peroxidases called DyPs. DyP enzymes oxidize high-redox potential anthraquinone dyes and were recently reported to oxidize lignin model compounds. The second major group of lignin-degrading enzymes, laccases, are found in plants, fungi, and bacteria and belong to the multicopper oxidase superfamily. They catalyze a one-electron oxidation with the concomitant four-electron reduction of molecular oxygen to water. Fungal laccases can oxidize phenolic lignin model compounds and have higher redox potential than bacterial laccases. In the presence of redox mediators, fungal laccases can oxidize non

Studies on hydrocarbon degradation by the bacterial isolate ...

African Journals Online (AJOL)

The hydrocarbon utilizing capability of Stenotrophomonas rhizophila (PM-1), isolated from oil contaminated soil composts from Western Ghats region of Karnataka was analyzed. In the bioremediation experiment, ONGC heavy crude oil and poly aromatic hydrocarbons (PAHs) utilization by the bacterial isolate was studied.

Surfaces wettability and morphology modulation in a fluorene derivative self-assembly system

Energy Technology Data Exchange (ETDEWEB)

Cao, Xinhua, E-mail: caoxhchem@163.com; Gao, Aiping; Zhao, Na; Yuan, Fangyuan; Liu, Chenxi; Li, Ruru

2016-04-15

Graphical abstract: - Highlights: • The different structures could be obtained in this self-assembly system. • A water-drop could freely roll on the xerogel film with the sliding angle of 15.0. • The superhydrophobic surface can be obtained via supramolecular self-assembly. - Abstract: A new organogelator based on fluorene derivative (gelator 1) was designed and synthesized. Organogels could be obtained via the self-assembly of the derivative in acetone, toluene, ethyl acetate, hexane, DMSO and petroleum ether. The self-assembly process was thoroughly characterized using field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), UV–vis, FT-IR and the contact angle. Surfaces with different morphologies and wetting properties were formed via the self-assembly of gelator 1 in the six different solvents. Interestingly, a superhydrophobic surface with a contact angle of 150° was obtained from organogel 1 in DMSO and exhibited the lotus-effect. The sliding angle necessary for a water droplet to move on the glass was only 15°. Hydrogen bonding and van der Waals forces were attributed as the main driving forces for gel formation.

Violacein: Properties and Production of a Versatile Bacterial Pigment

Directory of Open Access Journals (Sweden)

Seong Yeol Choi

2015-01-01

Full Text Available Violacein-producing bacteria, with their striking purple hues, have undoubtedly piqued the curiosity of scientists since their first discovery. The bisindole violacein is formed by the condensation of two tryptophan molecules through the action of five proteins. The genes required for its production, vioABCDE, and the regulatory mechanisms employed have been studied within a small number of violacein-producing strains. As a compound, violacein is known to have diverse biological activities, including being an anticancer agent and being an antibiotic against Staphylococcus aureus and other Gram-positive pathogens. Identifying the biological roles of this pigmented molecule is of particular interest, and understanding violacein’s function and mechanism of action has relevance to those unmasking any of its commercial or therapeutic benefits. Unfortunately, the production of violacein and its related derivatives is not easy and so various groups are also seeking to improve the fermentative yields of violacein through genetic engineering and synthetic biology. This review discusses the recent trends in the research and production of violacein by both natural and genetically modified bacterial strains.

The Complete Multipartite Genome Sequence of Cupriavidus necator JMP134, a Versatile Pollutant Degrader

Energy Technology Data Exchange (ETDEWEB)

Lykidis, Athanasios; Perez-Pantoja, Danilo; Ledger, Thomas; Mavromatis, Kostantinos; Anderson, Iain J.; Ivanova, Natalia N.; Hooper, Sean D.; Lapidus, Alla; Lucas, Susan; Gonzalez, Bernardo; Kyrpides, Nikos C.

2010-02-01

Cupriavidus necator JMP134 (formerly Ralstonia eutropha JMP134) is a Gram-negative {beta}-proteobacterium able to degrade a variety of chloroaromatic compounds and chemically-related pollutants. It was originally isolated based on its ability to use 2,4 dichlorophenoxyacetic acid (2,4-D) as a sole carbon and energy source [1]. In addition to 2,4-D, this strain can also grow on a variety of aromatic substrates, such as 4-chloro-2-methylphenoxyacetate (MCPA), 3-chlorobenzoic acid (3-CB) [2], 2,4,6-trichlorophenol [3], and 4-fluorobenzoate [4]. The genes necessary for 2,4-D utilization have been identified. They are located in two clusters on plasmid pPJ4: tfd{sub I} and tfd{sub II} [5,6,7,8]. The sequence and analysis of plasmid pJP4 was reported and a congruent model for bacterial adaptation to chloroaromatic pollutants was proposed [9]. According to this model, catabolic gene clusters assemble in a modular manner into broad-host-range plasmid backbones by means of repeated chromosomal capture events. Cupriavidus and related Burkholderia genomes are typically multipartite, composed of two large replicons (chromosomes) accompanied by classical plasmids. Previous work with Burkholderia xenovorans LB400 revealed a differential gene distribution with core functions preferentially encoded by the larger chromosome and secondary functions by the smaller [10]. It has been proposed that the secondary chromosomes in many bacteria originated from ancestral plasmids which, in turn, had been the recipient of genes transferred earlier from ancestral primary chromosomes [11]. The existence of multiple Cupriavidus and Burkholderia genomes provides the opportunity for comparative studies that will lead to a better understanding of the evolutionary mechanisms for the formation of multipartite genomes and the relation with biodegradation abilities.

Sintésis y propiedades fotofísicas de compuestos de platino y paladio con ligandos (fluoren-9-iliden) metanoditiolato

OpenAIRE

Pérez Cadenas, María

2007-01-01

En este trabajo se ha realizado la síntesis y caracterización estructural de complejos de platino y paladio con el ligando (fluoren-9-iliden) metanoditiolato y sus derivados 2,7-disustituídos. Se ha estudiado la influencia del carácter fuertemente dador de los nuevos ligandos en las estructuras, reactividades, comportamiento redox y propiedades fotofísicas de sus complejos metálicos, así como las posibilidades de agregación de centros metálicos adicionales y su influencia en las propiedades f...

Copper effects on bacterial activity of estuarine silty sediments

Science.gov (United States)

Almeida, Adelaide; Cunha, Ângela; Fernandes, Sandra; Sobral, Paula; Alcântara, Fernanda

2007-07-01

Bacteria of silty estuarine sediments were spiked with copper to 200 μg Cu g -1 dry weight sediment in order to assess the impact of copper on bacterial degradation of organic matter and on bacterial biomass production. Bacterial density was determined by direct counting under epifluorescence microscopy and bacterial production by the incorporation of 3H-Leucine. Leucine turnover rate was evaluated by 14C-leucine incorporation and ectoenzymatic activities were estimated as the hydrolysis rate of model substrates for β-glucosidase and leucine-aminopeptidase. The presence of added copper in the microcosms elicited, after 21 days of incubation, generalised anoxia and a decrease in organic matter content. The non-eroded surface of the copper-spiked sediment showed, when compared to the control, a decrease in bacterial abundance and significant lower levels of bacterial production and of leucine turnover rate. Bacterial production and leucine turnover rate decreased to 1.4% and 13% of the control values, respectively. Ectoenzymatic activities were also negatively affected but by smaller factors. After erosion by the water current in laboratory flume conditions, the eroded surface of the control sediment showed a generalised decline in all bacterial activities. The erosion of the copper-spiked sediment showed, however, two types of responses with respect to bacterial activities at the exposed surface: positive responses of bacterial production and leucine turnover rate contrasting with slight negative responses of ectoenzymatic activities. The effects of experimental erosion in the suspended cells were also different in the control and in the copper-spiked sediment. Bacterial cells in the control microcosm exhibited, when compared to the non-eroded sediment cells, decreases in all activities after the 6-h suspension. The response of the average suspended copper-spiked sediment cell differed from the control by a less sharp decrease in ectoenzymatic activities and

Bacterial Carriers for Glioblastoma Therapy

Directory of Open Access Journals (Sweden)

Nalini Mehta

2017-03-01

Full Text Available Treatment of aggressive glioblastoma brain tumors is challenging, largely due to diffusion barriers preventing efficient drug dosing to tumors. To overcome these barriers, bacterial carriers that are actively motile and programmed to migrate and localize to tumor zones were designed. These carriers can induce apoptosis via hypoxia-controlled expression of a tumor suppressor protein p53 and a pro-apoptotic drug, Azurin. In a xenograft model of human glioblastoma in rats, bacterial carrier therapy conferred a significant survival benefit with 19% overall long-term survival of >100 days in treated animals relative to a median survival of 26 days in control untreated animals. Histological and proteomic analyses were performed to elucidate the safety and efficacy of these carriers, showing an absence of systemic toxicity and a restored neural environment in treated responders. In the treated non-responders, proteomic analysis revealed competing mechanisms of pro-apoptotic and drug-resistant activity. This bacterial carrier opens a versatile avenue to overcome diffusion barriers in glioblastoma by virtue of its active motility in extracellular space and can lead to tailored therapies via tumor-specific expression of tumoricidal proteins.

Influence of bacteria on degradation of bioplastics

Science.gov (United States)

Blinková, M.; Boturová, K.

2017-10-01

The degradation rate of bioplastic in soil is closely related to the diversity of soil microbiota. To investigate the effect of soil bacterial on biodegradation, 4 bacterial strains of soil - Pseudomonas chlororaphis, Kocuria rosea, Cupriavidus necator and Bacillus cereus, were used to accelerate the decomposition of bioplastics manufactured from Polylactid acid (PLA) by direct action during 250 days. The best results were obtained with bacterial strains Cupriavidus necator and Pseudomonas chlororaphis that were isolated of lagoons with anthropogenic sediments.

Fourier transform infrared spectroscopy as a metabolite fingerprinting tool for monitoring the phenotypic changes in complex bacterial communities capable of degrading phenol.

Science.gov (United States)

Wharfe, Emma S; Jarvis, Roger M; Winder, Catherine L; Whiteley, Andrew S; Goodacre, Royston

2010-12-01

The coking process produces great volumes of wastewater contaminated with pollutants such as cyanides, sulfides and phenolics. Chemical and physical remediation of this wastewater removes the majority of these pollutants; however, these processes do not remove phenol and thiocyanate. The removal of these compounds has been effected during bioremediation with activated sludge containing a complex microbial community. In this investigation we acquired activated sludge from an industrial bioreactor capable of degrading phenol. The sludge was incubated in our laboratory and monitored for its ability to degrade phenol over a 48 h period. Multiple samples were taken across the time-course and analysed by Fourier transform infrared (FT-IR) spectroscopy. FT-IR was used as a whole-organism fingerprinting approach to monitor biochemical changes in the bacterial cells during the degradation of phenol. We also investigated the ability of the activated sludge to degrade phenol following extended periods (2-131 days) of storage in the absence of phenol. A reduction was observed in the ability of the microbial community to degrade phenol and this was accompanied by a detectable biochemical change in the FT-IR fingerprint related to cellular phenotype of the microbial community. In the absence of phenol a decrease in thiocyanate vibrations was observed, reflecting the ability of these communities to degrade this substrate. Actively degrading communities showed an additional new band in their FT-IR spectra that could be attributed to phenol degradation products from the ortho- and meta-cleavage of the aromatic ring. This study demonstrates that FT-IR spectroscopy when combined with chemometric analysis is a very powerful high throughput screening approach for assessing the metabolic capability of complex microbial communities. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Effect of Sphingobium yanoikuyae B1 inoculation on bacterial community dynamics and polycyclic aromatic hydrocarbon degradation in aged and freshly PAH-contaminated soils

International Nuclear Information System (INIS)

Cunliffe, Michael; Kertesz, Michael A.

2006-01-01

Sphingobium yanoikuyae B1 is able to degrade a range of polycyclic aromatic hydrocarbons (PAHs) and as a sphingomonad belongs to one of the dominant genera found in PAH-contaminated soils. We examined the ecological effect that soil inoculation with S. yanoikuyae B1 has on the native bacterial community in three different soils: aged PAH-contaminated soil from an industrial site, compost freshly contaminated with PAHs and un-contaminated compost. Survival of S. yanoikuyae B1 was dependent on the presence of PAHs, and the strain was unable to colonize un-contaminated compost. Inoculation with S. yanoikuyae B1 did not cause extensive changes in the native bacterial community of either soil, as assessed by denaturing gel electrophoresis, but its presence led to an increase in the population level of two other species in the aged contaminated soil community and appeared to have an antagonistic affect on several members of the contaminated compost community, indicating niche competition. - Sphingobium yanoikuyae B1 does not cause major changes in the native bacterial community while colonizing PAH-contaminated soils, but some niche competition is evident

Synergistic degradation of chlorinated hydrocarbons with microorganisms and zero valent iron

Science.gov (United States)

Schöftner, Philipp; Summer, Dorothea; Leitner, Simon; Watzinger, Andrea; Wimmer, Bernhard; Reichenauer, Thomas

2016-04-01

Sites contaminated with chlorinated hydrocarbons (CHC) are located mainly within build-up regions. Therefore in most cases only in-situ technologies without excavation of soil material can be used for remediation. This project examines a novel in-situ remediation method, in which the biotic degradation via bacteria is combined with abiotic degradation via zero-valent iron particles (ZVI). ZVI particles are injected into the aquifer where CHC-molecules are reductively dechlorinated. However Fe0 is also oxidized by reaction with water leading to generation of H2 without any CHC degradation. To achieve biotic degradation often strictly anaerobic strains of the bacteria Dehalococcoides are used. These bacteria can dechlorinate CHC by utilizing H2. By combining these processes the H2, produced during the anaerobic corrosion of Fe0, could be used by bacteria for further CHC degradation. Therefore the amount of used Fe0 and as a consequence also remediation costs could be reduced. Additionally the continuous supply of H2 could make the bacterial degradation more controllable. Different Fe0 particles (nano- and micro-scale) were tested for their perchloroethene (PCE) degradation rate and H2 production rate in microcosms. PCE-degradation rate by different bacterial cultures was investigated in the same microcosm system. In course of these experiments the 13C enrichment factors of the PCE degradation of the different particles and cultures were determined to enable the differentiation of biotic and abiotic degradation. Preliminary results showed, that the nano-scale particles reacted faster with PCE and water than their micro-scaled counterparts. The PCE degradation via micro-scaled particles lead to 13C enrichment factors in the range of -3,6 ‰ ± 0,6 to -9,5 ‰ ± 0,2. With one of the examined bacterial cultures a fast reduction of PCE to ethene was observed. Although PCE and TCE were completely degraded by this culture the metabolites DCE and VC could still be detected

Evaluation of various pesticides-degrading pure bacterial cultures ...

African Journals Online (AJOL)

Due to the intensive use of pesticides within the greenhouse-rose production, remediation of polluted soils has become a hot topic for researchers in recent decades. Several bacterial strains having the ability to utilize various pesticides as a sole source of carbon and energy were isolated from pesticidecontaminated soils ...

Environmental, biochemical and genetic drivers of DMSP degradation and DMS production in the Sargasso Sea.

Science.gov (United States)

Levine, Naomi Marcil; Varaljay, Vanessa A; Toole, Dierdre A; Dacey, John W H; Doney, Scott C; Moran, Mary Ann

2012-05-01

Dimethylsulfide (DMS) is a climatically relevant trace gas produced and cycled by the surface ocean food web. Mechanisms driving intraannual variability in DMS production and dimethylsulfoniopropionate (DMSP) degradation in open-ocean, oligotrophic regions were investigated during a 10-month time-series at the Bermuda Atlantic Time-series Study site in the Sargasso Sea. Abundance and transcription of bacterial DMSP degradation genes, DMSP lyase enzyme activity, and DMS and DMSP concentrations, consumption rates and production rates were quantified over time and depth. This interdisciplinary data set was used to test current hypotheses of the role of light and carbon supply in regulating upper-ocean sulfur cycling. Findings supported UV-A-dependent phytoplankton DMS production. Bacterial DMSP degraders may also contribute significantly to DMS production when temperatures are elevated and UV-A dose is moderate, but may favour DMSP demethylation under low UV-A doses. Three groups of bacterial DMSP degraders with distinct intraannual variability were identified and niche differentiation was indicated. The combination of genetic and biochemical data suggest a modified 'bacterial switch' hypothesis where the prevalence of different bacterial DMSP degradation pathways is regulated by a complex set of factors including carbon supply, temperature and UV-A dose. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Associations of Pseudomonas species and forage grasses enhance degradation of chlorinated benzoic acids in soil

Energy Technology Data Exchange (ETDEWEB)

Siciliano, S. D.

1998-12-01

Using chlorinated benzoic acid (CBA) as a model compound, this study attempted to show that microorganisms and plants can be used as bioremediation agents to clean up contaminated soil sites in a cost effective and environmentally friendly manner. CBA was used because it is present in soils contaminated with polychlorinated biphenyls (PCBs), or chlorinated pesticides. Sixteen forage grasses were screened in combination with 12 bacterial inoculants for their ability to promote the degradation of CBA in soil. Five associations of plants and bacteria were found to degrade CBA to a greater extent than plants without bacterial inoculants. Bacterial inoculants were shown to stimulate CBA degradation by altering the microbial community present on the root surface and thereby increasing the ability of this community to degrade CBA.

Biotechnological applications of bacterial cellulases

Czech Academy of Sciences Publication Activity Database

Menéndez, E.; García-Fraile, Paula; Rivas, R.

2015-01-01

Roč. 2, č. 3 (2015), s. 163-182 ISSN 2306-5354 R&D Projects: GA MŠk(CZ) EE2.3.30.0003 Institutional support: RVO:61388971 Keywords : Biotechnological applications * Bacterial cellulases * Cellulose degradation Subject RIV: EE - Microbiology, Virology

Hydrocarbon pollutants shape bacterial community assembly of harbor sediments

KAUST Repository

Barbato, Marta

2016-02-02

Petroleum pollution results in co-contamination by different classes of molecules, entailing the occurrence of marine sediments difficult to remediate, as in the case of the Ancona harbor (Mediterranean Sea, Italy). Autochthonous bioaugmentation (ABA), by exploiting the indigenous microbes of the environment to be treated, could represent a successful bioremediation strategy. In this perspective we aimed to i) identify the main drivers of the bacterial communities\\' richness in the sediments, ii) establish enrichment cultures with different hydrocarbon pollutants evaluating their effects on the bacterial communities\\' composition, and iii) obtain a collection of hydrocarbon degrading bacteria potentially exploitable in ABA. The correlation between the selection of different specialized bacterial populations and the type of pollutants was demonstrated by culture-independent analyses, and by establishing a collection of bacteria with different hydrocarbon degradation traits. Our observations indicate that pollution dictates the diversity of sediment bacterial communities and shapes the ABA potential in harbor sediments.

Evaluation of various pesticides-degrading pure bacterial cultures ...

African Journals Online (AJOL)

IASA

2016-10-05

Oct 5, 2016 ... Full Length Research Paper ... field experimentations for the degradation of various pesticides like Ridomil ... hazardous/toxic chemicals which might be harmful to the ... The isolation of microorganisms involved in pesticide/.

Bovine intestinal bacteria inactivate and degrade ceftiofur and ceftriaxone with multiple beta-lactamases.

Science.gov (United States)

Wagner, R Doug; Johnson, Shemedia J; Cerniglia, Carl E; Erickson, Bruce D

2011-11-01

The veterinary cephalosporin drug ceftiofur is rapidly degraded in the bovine intestinal tract. A cylinder-plate assay was used to detect microbiologically active ceftiofur, and high-performance liquid chromatography-mass spectrometry analysis was used to quantify the amount of ceftiofur remaining after incubation with bovine intestinal anaerobic bacteria, which were isolated from colon contents or feces from 8 cattle. Ninety-six percent of the isolates were able to inactivate ceftiofur to some degree, and 54% actually degraded the drug. None of 9 fungal isolates inactivated or degraded ceftiofur. Facultative and obligate anaerobic bacterial species that inactivated or degraded ceftiofur were identified with Vitek and Biolog systems, respectively. A subset of ceftiofur degraders also degraded the chemically similar drug ceftriaxone. Most of the species of bacteria that degraded ceftiofur belonged to the genera Bacillus and Bacteroides. PCR analysis of bacterial DNA detected specific β-lactamase genes. Bacillus cereus and B. mycoides isolates produced extended-spectrum β-lactamases and metallo-β-lactamases. Seven isolates of Bacteroides spp. produced multiple β-lactamases, including possibly CepA, and metallo-β-lactamases. Isolates of Eubacterium biforme, Bifidobacterium breve, and several Clostridium spp. also produced ceftiofur-degrading β-lactamases. An agar gel overlay technique on isoelectric focusing separations of bacterial lysates showed that β-lactamase enzymes were sufficient to degrade ceftiofur. These results suggest that ceftiofur is inactivated nonenzymatically and degraded enzymatically by multiple β-lactamases from bacteria in the large intestines of cattle.

Bovine Intestinal Bacteria Inactivate and Degrade Ceftiofur and Ceftriaxone with Multiple β-Lactamases▿

Science.gov (United States)

Wagner, R. Doug; Johnson, Shemedia J.; Cerniglia, Carl E.; Erickson, Bruce D.

2011-01-01

The veterinary cephalosporin drug ceftiofur is rapidly degraded in the bovine intestinal tract. A cylinder-plate assay was used to detect microbiologically active ceftiofur, and high-performance liquid chromatography-mass spectrometry analysis was used to quantify the amount of ceftiofur remaining after incubation with bovine intestinal anaerobic bacteria, which were isolated from colon contents or feces from 8 cattle. Ninety-six percent of the isolates were able to inactivate ceftiofur to some degree, and 54% actually degraded the drug. None of 9 fungal isolates inactivated or degraded ceftiofur. Facultative and obligate anaerobic bacterial species that inactivated or degraded ceftiofur were identified with Vitek and Biolog systems, respectively. A subset of ceftiofur degraders also degraded the chemically similar drug ceftriaxone. Most of the species of bacteria that degraded ceftiofur belonged to the genera Bacillus and Bacteroides. PCR analysis of bacterial DNA detected specific β-lactamase genes. Bacillus cereus and B. mycoides isolates produced extended-spectrum β-lactamases and metallo-β-lactamases. Seven isolates of Bacteroides spp. produced multiple β-lactamases, including possibly CepA, and metallo-β-lactamases. Isolates of Eubacterium biforme, Bifidobacterium breve, and several Clostridium spp. also produced ceftiofur-degrading β-lactamases. An agar gel overlay technique on isoelectric focusing separations of bacterial lysates showed that β-lactamase enzymes were sufficient to degrade ceftiofur. These results suggest that ceftiofur is inactivated nonenzymatically and degraded enzymatically by multiple β-lactamases from bacteria in the large intestines of cattle. PMID:21876048

Biochemical activities of 1,2-dichloroethane (DCA) degrading bacteria

African Journals Online (AJOL)

Five indigenous DCA degrading bacterial isolates capable of completely degrading DCA under aerobic conditions recently isolated from South African waste water treatment facilities, were found to belong to the genus Ancylobacter. The specific activities of the enzymes in DCA catabolism were compared with previously ...

The human PDI family: Versatility packed into a single fold

DEFF Research Database (Denmark)

Appenzeller-Herzog, Christian; Ellgaard, Lars

2007-01-01

in promoting oxidative protein folding in the ER has been extended in recent years to include roles in other processes such as ER-associated degradation (ERAD), trafficking, calcium homeostasis, antigen presentation and virus entry. Some of these functions are performed by non-catalytic members of the family...... that lack the active-site cysteines. Regardless of their function, all human PDIs contain at least one domain of approximately 100 amino acid residues with structural homology to thioredoxin. As we learn more about the individual proteins of the family, a complex picture is emerging that emphasizes as much...... their differences as their similarities, and underlines the versatility of the thioredoxin fold. Here, we primarily explore the diversity of cellular functions described for the human PDIs. Udgivelsesdato: 2007-Dec-3...

Accumulation of metabolites during bacterial degradation of PAH-mixtures

Energy Technology Data Exchange (ETDEWEB)

Vila, J.; Lopez, Z.; Bauza, J.I. [Universitat de Barcelona (Spain). Department de Microbiologia; Minguillon, C. [Parc Cientific de Barcelona (ES). Institut de Recerca de Barcelona (IRB-PCB); Grifoll, M.

2003-07-01

In a previous work we identified a number of metabolites accumulated during growth in pyrene by Mycobacterium sp. AP1, and proposed a metabolic pathway for pyrene utilization. In order to confirm and complete this pathway we have isolated and identified the pyrene-degrading strains Mycobacterium sp. PGP2, CP1 and CP2. During growth on pyrene, strains AP1, PGP2, CP1 and CP2 accumulated 4,5-cis-pyrene-dihydrodiol, 4,5-phenanthrene dicarboxylic acid, 4-phenanthrene carboxylic acid, 3,4-dihydroxy-3-hydrophenanthrene-4-carboxylic acid, phthalic acid, and 6,6'-dihydroxy-2,2'-biphenyl dicarboxylic acid. Strains AP1, PGP2, CP1 and CP2 also grew on fluoranthene accumulating acenaphthenone, naphthalene-1,8-dicarboxylic acid, 9-fluorenone-1-carboxylic acid, Z-9-carboxymethylenefluorene-1-carboxylic acid and benzene-1,2,3-tricarboxylic acid. Similar metabolites were produced during growth onf fluoranthene by the Gram-positive strains CFt2 and CFt6, isolated by their capability of using this PAH as a sole source of carbon and energy. These fluoranthene-degrading strains also accumulated cis-1,9a-dihydroxy-1-hydrofluorene-9-one-8-carboxylic acid. In addition to pyrene and fluoranthene, all pyrene-degrading utilized phenanthrene as a sole source of carbon and energy, while the fluoranthene-degrading strains were unable to utilize pyrene or phenanthrene. Mycobacterium sp. AP1 acted on a wide range of PAHs, accumulating aromatic dicarboxylic acids, hydroxyacids, and ketones resulting from dioxygenation and ortho-cleavage, dioxygenation and meta-cleavage, and monooxygenation reactions. In cultures of strains AP1 and CP1 with a defined PAH-mixture only 20% removal of the parent compounds was observed. Analysis of acidic extracts showed the accumulation of the anticipated aromatic acids, suggesting that accumulation of acidic compounds could prevent further degradation of the mixture. Those results led us to isolation of strains DF11 and OH3, able to grow on the selected

Laboratory scale bioremediation of diesel hydrocarbon in soil by indigenous bacterial consortium.

Science.gov (United States)

Sharma, Anjana; Rehman, Meenal Budholia

2009-09-01

In vitro experiment was performed by taking petrol pump soils and diesel in flasks with the micronutrients and macronutrients supplements. Cemented bioreactors having sterilized soil and diesel was used for in vivo analysis of diesel hydrocarbon degradation. There were two sets of experiments, first having three bioreactors (1) inoculated by KI. pneumoniae subsp. aerogenes with soil and diesel; (2) with addition of NH4NO3; and (3) served as control. In second set, one bioreactor was inoculated by bacterial consortium containing Moraxella saccharolytica, Alteromonas putrefaciens, KI. pneumoniae subsp. aerogenes and Pseudomonas fragi along with soil and diesel. The remaining two bioreactors (having NH4NO3 and control) were similar to the first set. The experiments were incubated for 30 days. Ability of bacterial inoculum to degrade diesel was analyzed through GC-MS. Smaller chain compounds were obtained after experimental period of 30 days. Rate of diesel degradation was better with the present bacterial consortium than individual bacteria. Present bacterial consortium can be a better choice for faster and complete remediation of contaminated hydrocarbon soils.

Research on heavy oil degradation by four thermophilic bacterial strains

Energy Technology Data Exchange (ETDEWEB)

Bao, M.; Chen, Q.; Liu, Z.; Li, Y. [Ocean Univ. of China, Qingdao, Shandong (China)

2009-07-01

The Shengli oilfield is the second largest onshore oil field in China, with a crude oil output of approximately 30 million tons per year. The large quantities of wastewater that are produced during thermal recovery methods have posed a challenge in terms of water reuse, reinjection and discharge. The important aspect of wastewater treatment is the removal of residual heavy oil. Biological methods are considered to be efficient in solving this problem. This paper reported on a study in which 4 thermophilic microorganisms which had the ability to biodegrade heavy oil were screened from heavy oil wastewater in the Shengli oilfield. Their degradation to heavy oil was discussed and the suitable biodegradation conditions of these bacteria were investigated. The study showed that the degrading efficiency of heavy oil by the 4 bacteria was up to 42.0, 47.6, 55.6 and 43.4 per cent in the wastewater which contained 500 mg per litre of heavy oil, respectively. The crude oil samples were analyzed using gas chromatography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS) before and after degradation. The single 4 strains demonstrated strong biodegradability to normal alkanes and aromatics, and the average degrading efficiency was about 50 and 35 per cent. The degrading efficiency of the mixed 4 strains was better than the single ones, particularly for the poor biodegradable hydrocarbons such as phenanthrenes and fluorines. 21 refs., 2 tabs., 17 figs.

The genome sequence of the commercially cultivated mushroom Agrocybe aegerita reveals a conserved repertoire of fruiting-related genes and a versatile suite of biopolymer-degrading enzymes.

Science.gov (United States)

Gupta, Deepak K; Rühl, Martin; Mishra, Bagdevi; Kleofas, Vanessa; Hofrichter, Martin; Herzog, Robert; Pecyna, Marek J; Sharma, Rahul; Kellner, Harald; Hennicke, Florian; Thines, Marco

2018-01-15

Agrocybe aegerita is an agaricomycete fungus with typical mushroom features, which is commercially cultivated for its culinary use. In nature, it is a saprotrophic or facultative pathogenic fungus causing a white-rot of hardwood in forests of warm and mild climate. The ease of cultivation and fructification on solidified media as well as its archetypal mushroom fruit body morphology render A. aegerita a well-suited model for investigating mushroom developmental biology. Here, the genome of the species is reported and analysed with respect to carbohydrate active genes and genes known to play a role during fruit body formation. In terms of fruit body development, our analyses revealed a conserved repertoire of fruiting-related genes, which corresponds well to the archetypal fruit body morphology of this mushroom. For some genes involved in fruit body formation, paralogisation was observed, but not all fruit body maturation-associated genes known from other agaricomycetes seem to be conserved in the genome sequence of A. aegerita. In terms of lytic enzymes, our analyses suggest a versatile arsenal of biopolymer-degrading enzymes that likely account for the flexible life style of this species. Regarding the amount of genes encoding CAZymes relevant for lignin degradation, A. aegerita shows more similarity to white-rot fungi than to litter decomposers, including 18 genes coding for unspecific peroxygenases and three dye-decolourising peroxidase genes expanding its lignocellulolytic machinery. The genome resource will be useful for developing strategies towards genetic manipulation of A. aegerita, which will subsequently allow functional genetics approaches to elucidate fundamentals of fruiting and vegetative growth including lignocellulolysis.

Critical evaluation of post-consumption food waste composting employing thermophilic bacterial consortium.

Science.gov (United States)

Awasthi, Mukesh Kumar; Selvam, Ammaiyappan; Lai, Ka Man; Wong, Jonathan W C

2017-12-01

Effect of single-function (oil degrading) and multi-functional bacterial consortium with zeolite as additive for post-consumption food waste (PCFW) composting was investigated through assessing the oil content reduction in a computer controlled 20-L composter. Three treatments of PCFWs combined with 10% zeolite were developed: Treatment-2 and Treatment-3 were inoculated with multi-functional (BC-1) and oil degrading bacterial consortium (BC-2), respectively, while T-1 was without bacterial inoculation and served as control. Results revealed that BC-2 inoculated treatment (T-3) was superior to control treatment and marginally better than T-2 in terms of oil degradation. The reduction of oil content was >97.8% in T-3 and 92.27% in T-2, while total organic matter degradation was marginally higher in T-2 (42.95%) than T-3 (41.67%). Other parameters of compost maturity including germination test indicated that T-2 was marginally better than T-3 and significantly enhanced the oily PCFW decomposition and shortened the composting period by 20days. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bacteria-mediated bisphenol A degradation.

Science.gov (United States)

Zhang, Weiwei; Yin, Kun; Chen, Lingxin

2013-07-01

Bisphenol A (BPA) is an important monomer in the manufacture of polycarbonate plastics, food cans, and other daily used chemicals. Daily and worldwide usage of BPA and BPA-contained products led to its ubiquitous distribution in water, sediment/soil, and atmosphere. Moreover, BPA has been identified as an environmental endocrine disruptor for its estrogenic and genotoxic activity. Thus, BPA contamination in the environment is an increasingly worldwide concern, and methods to efficiently remove BPA from the environment are urgently recommended. Although many factors affect the fate of BPA in the environment, BPA degradation is mainly depended on the metabolism of bacteria. Many BPA-degrading bacteria have been identified from water, sediment/soil, and wastewater treatment plants. Metabolic pathways of BPA degradation in specific bacterial strains were proposed, based on the metabolic intermediates detected during the degradation process. In this review, the BPA-degrading bacteria were summarized, and the (proposed) BPA degradation pathway mediated by bacteria were referred.

Activity and stability of a complex bacterial soil community under simulated Martian conditions

Science.gov (United States)

Hansen, Aviaja Anna; Merrison, Jonathan; Nørnberg, Per; Aagaard Lomstein, Bente; Finster, Kai

2005-04-01

A simulation experiment with a complex bacterial soil community in a Mars simulation chamber was performed to determine the effect of Martian conditions on community activity, stability and survival. At three different depths in the soil core short-term effects of Martian conditions with and without ultraviolet (UV) exposure corresponding to 8 Martian Sol were compared. Community metabolic activities and functional diversity, measured as glucose respiration and versatility in substrate utilization, respectively, decreased after UV exposure, whereas they remained unaffected by Martian conditions without UV exposure. In contrast, the numbers of culturable bacteria and the genetic diversity were unaffected by the simulated Martian conditions both with and without UV exposure. The genetic diversity of the soil community and of the colonies grown on agar plates were evaluated by denaturant gradient gel electrophoresis (DGGE) on DNA extracts. Desiccation of the soil prior to experimentation affected the functional diversity by decreasing the versatility in substrate utilization. The natural dominance of endospores and Gram-positive bacteria in the investigated Mars-analogue soil may explain the limited effect of the Mars incubations on the survival and community structure. Our results suggest that UV radiation and desiccation are major selecting factors on bacterial functional diversity in terrestrial bacterial communities incubated under simulated Martian conditions. Furthermore, these results suggest that forward contamination of Mars is a matter of great concern in future space missions.

Interaction of polybrominated diphenyl ethers (PBDEs) with anaerobic mixed bacterial cultures isolated from river sediment

Energy Technology Data Exchange (ETDEWEB)

Yen, J H; Liao, W C; Chen, W C [Department of Agricultural Chemistry, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Wang, Y.S., E-mail: yswang@ntu.edu.tw [Department of Agricultural Chemistry, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China)

2009-06-15

The degradation of flame retardant polybrominated diphenyl ethers (PBDE), including tetra-brominated diphenyl ether (BDE-47), penta-brominated diphenyl ether (BDE-99 and -100), and hexa-brominated diphenyl ether (BDE-153 and -154), by anaerobic bacterial mixed cultures isolated from river sediment was investigated. The effects of PBDEs on changes of anaerobic bacterial community in sediment culture were also studied. Sediments were collected from Er-Jen River and Nan-Kan River basins, which were both heavily polluted rivers in Taiwan, and bacteria from the sediment samples were enriched before the experiment was conducted. Into the anaerobic bacterial mixed cultures, 0.1 {mu}g/mL of PBDEs was added followed by incubation under 30 deg. C for 70 days. Residues of PBDE were determined by gas chromatography with electron capture detector (GC-ECD), and the changes of bacterial community were analyzed by denaturing gradient gel electrophoresis (DGGE). Less than 20% of PBDEs were degraded after 70 days of incubation in all samples except for BDE-47 from the Nan-Kan River sediment. In that culture, BDE-47 was found to have notably degraded. In particular, after 42 days of incubation; BDE-47 was degraded, suddenly and sharply, to a negligible level on Day 70, and the result was confirmed by a repeated experiment. An interesting result was that although BDE-47 was degraded fast in the Nan-Kan River sediment, the bacterial communities did not shift significantly as we had speculated at Day 70. From UPGMA dendrograms, PBDEs changed the composition of bacterial communities, and the extents varied with the variety of PBDE congeners. By the amendment with BDE-153 or -154, bacterial communities would be changed immediately and irreversibly throughout the rest of the incubation period. No significant difference in degradation of PBDEs was observed between sediment bacteria from Er-Jen River and Nan-Kan River. However, the results verified the persistence of PBDEs in the environment.

Interaction of polybrominated diphenyl ethers (PBDEs) with anaerobic mixed bacterial cultures isolated from river sediment

International Nuclear Information System (INIS)

Yen, J.H.; Liao, W.C.; Chen, W.C.; Wang, Y.S.

2009-01-01

The degradation of flame retardant polybrominated diphenyl ethers (PBDE), including tetra-brominated diphenyl ether (BDE-47), penta-brominated diphenyl ether (BDE-99 and -100), and hexa-brominated diphenyl ether (BDE-153 and -154), by anaerobic bacterial mixed cultures isolated from river sediment was investigated. The effects of PBDEs on changes of anaerobic bacterial community in sediment culture were also studied. Sediments were collected from Er-Jen River and Nan-Kan River basins, which were both heavily polluted rivers in Taiwan, and bacteria from the sediment samples were enriched before the experiment was conducted. Into the anaerobic bacterial mixed cultures, 0.1 μg/mL of PBDEs was added followed by incubation under 30 deg. C for 70 days. Residues of PBDE were determined by gas chromatography with electron capture detector (GC-ECD), and the changes of bacterial community were analyzed by denaturing gradient gel electrophoresis (DGGE). Less than 20% of PBDEs were degraded after 70 days of incubation in all samples except for BDE-47 from the Nan-Kan River sediment. In that culture, BDE-47 was found to have notably degraded. In particular, after 42 days of incubation; BDE-47 was degraded, suddenly and sharply, to a negligible level on Day 70, and the result was confirmed by a repeated experiment. An interesting result was that although BDE-47 was degraded fast in the Nan-Kan River sediment, the bacterial communities did not shift significantly as we had speculated at Day 70. From UPGMA dendrograms, PBDEs changed the composition of bacterial communities, and the extents varied with the variety of PBDE congeners. By the amendment with BDE-153 or -154, bacterial communities would be changed immediately and irreversibly throughout the rest of the incubation period. No significant difference in degradation of PBDEs was observed between sediment bacteria from Er-Jen River and Nan-Kan River. However, the results verified the persistence of PBDEs in the environment.

Construction and applications of DNA probes for detection of polychlorinated biphenyl-degrading genotypes in toxic organic-contaminated soil environments

International Nuclear Information System (INIS)

Walia, S.; Khan, A.; Rosenthal, N.

1990-01-01

Several DNA probes for polychlorinated biphenyl (PCB)-degrading genotypes were constructed from PCB-degrading bacteria. These laboratory-engineered DNA probes were used for the detection, enumeration, and isolation of specific bacteria degrading PCBs. Dot blot analysis of purified DNA from toxic organic chemical-contaminated soil bacterial communities showed positive DNA-DNA hybridization with a 32P-labeled DNA probe (pAW6194, cbpABCD). Less than 1% of bacterial colonies isolated from garden topsoil and greater than 80% of bacteria isolated from PCB-contaminated soils showed DNA homologies with 32P-labeled DNA probes. Some of the PCB-degrading bacterial isolates detected by the DNA probe method did not show biphenyl clearance. The DNA probe method was found to detect additional organisms with greater genetic potential to degrade PCBs than the biphenyl clearance method did. Results from this study demonstrate the usefulness of DNA probes in detecting specific PCB-degrading bacteria, abundance of PCB-degrading genotypes, and genotypic diversity among PCB-degrading bacteria in toxic chemical-polluted soil environments. We suggest that the DNA probe should be used with caution for accurate assessment of PCB-degradative capacity within soils and further recommend that a combination of DNA probe and biodegradation assay be used to determine the abundance of PCB-degrading bacteria in the soil bacterial community

The bacterial-fungal energy channel concept challenged by enormous functional versatility of soil protists

NARCIS (Netherlands)

Geisen, Stefan

2016-01-01

Abstract Protists (=protozoa) are commonly treated as bacterivores that control the bacterial energy channel in soil food webs. This ecologist’s perspective is, however, challenged by taxonomic studies showing that a range of protists feed on fungi, other protists and even nematodes. Recently, it

The bacterial-fungal energy channel concept challenged by enormous functional versatility of soil protists

NARCIS (Netherlands)

Geisen, Stefan

2016-01-01

Protists (=protozoa) are commonly treated as bacterivores that control the bacterial energy channel in soil food webs. This ecologist’s perspective is, however, challenged by taxonomic studies showing that a range of protists feed on fungi, other protists and even nematodes. Recently, it was

Re-engineering of Bacterial Luciferase; For New Aspects of Bioluminescence.

Science.gov (United States)

Kim, Da-Som; Choi, Jeong-Ran; Ko, Jeong-Ae; Kim, Kangmin

2018-01-01

Bacterial luminescence is the end-product of biochemical reactions catalyzed by the luciferase enzyme. Nowadays, this fascinating phenomenon has been widely used as reporter and/or sensors to detect a variety of biological and environmental processes. The enhancement or diversification of the luciferase activities will increase the versatility of bacterial luminescence. Here, to establish the strategy for luciferase engineering, we summarized the identity and relevant roles of key amino acid residues modulating luciferase in Vibrio harveyi, a model luminous bacterium. The current opinions on crystal structures and the critical amino acid residues involved in the substrate binding sites and unstructured loop have been delineated. Based on these, the potential target residues and/or parameters for enzyme engineering were also suggested in limited scale. In conclusion, even though the accurate knowledge on the bacterial luciferase is yet to be reported, the structure-guided site-directed mutagenesis approaches targeting the regulatory amino acids will provide a useful platform to re-engineer the bacterial luciferase in the future. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Removal of Triphenylmethane Dyes by Bacterial Consortium

Directory of Open Access Journals (Sweden)

Jihane Cheriaa

2012-01-01

Full Text Available A new consortium of four bacterial isolates (Agrobacterium radiobacter; Bacillus spp.; Sphingomonas paucimobilis, and Aeromonas hydrophila-(CM-4 was used to degrade and to decolorize triphenylmethane dyes. All bacteria were isolated from activated sludge extracted from a wastewater treatment station of a dyeing industry plant. Individual bacterial isolates exhibited a remarkable color-removal capability against crystal violet (50 mg/L and malachite green (50 mg/L dyes within 24 h. Interestingly, the microbial consortium CM-4 shows a high decolorizing percentage for crystal violet and malachite green, respectively, 91% and 99% within 2 h. The rate of chemical oxygen demand (COD removal increases after 24 h, reaching 61.5% and 84.2% for crystal violet and malachite green, respectively. UV-Visible absorption spectra, FTIR analysis and the inspection of bacterial cells growth indicated that color removal by the CM-4 was due to biodegradation. Evaluation of mutagenicity by using Salmonella typhimurium test strains, TA98 and TA100 studies revealed that the degradation of crystal violet and malachite green by CM-4 did not lead to mutagenic products. Altogether, these results demonstrated the usefulness of the bacterial consortium in the treatment of the textile dyes.

Microbial degradation of polycyclic aromatic hydrocarbons (PAHs). Pt. 1

International Nuclear Information System (INIS)

Eichler, B.; Bryniok, D.; Vorbeck, C.; Lutz, M.; Ackermann, B.; Freier-Schroeder, D.; Knackmuss, H.J.

1992-01-01

Productive degradation of the higher molecular PAHs benz(a)anthracene (four rings), benzo(a)pyrene and benzo(k)fluoranthene (five rings) through pure bacterial cultures is demonstrated in this paper for the first time. Consequently, a degradation potential for lower and higher molecular polycyclic aromatics up to five rings exists both in the ground of the fromer coking site and in the ground of the former gas works of Stuttgart. Further samples from contaminated soils, coking waste water and sediments showed similar results. This suggests that the bacterial flora present in the soil itself can be successfully used to clean up contaminated ground. (orig.) [de

High-throughput metagenomic analysis of petroleum-contaminated soil microbiome reveals the versatility in xenobiotic aromatics metabolism.

Science.gov (United States)

Bao, Yun-Juan; Xu, Zixiang; Li, Yang; Yao, Zhi; Sun, Jibin; Song, Hui

2017-06-01

The soil with petroleum contamination is one of the most studied soil ecosystems due to its rich microorganisms for hydrocarbon degradation and broad applications in bioremediation. However, our understanding of the genomic properties and functional traits of the soil microbiome is limited. In this study, we used high-throughput metagenomic sequencing to comprehensively study the microbial community from petroleum-contaminated soils near Tianjin Dagang oilfield in eastern China. The analysis reveals that the soil metagenome is characterized by high level of community diversity and metabolic versatility. The metageome community is predominated by γ-Proteobacteria and α-Proteobacteria, which are key players for petroleum hydrocarbon degradation. The functional study demonstrates over-represented enzyme groups and pathways involved in degradation of a broad set of xenobiotic aromatic compounds, including toluene, xylene, chlorobenzoate, aminobenzoate, DDT, methylnaphthalene, and bisphenol. A composite metabolic network is proposed for the identified pathways, thus consolidating our identification of the pathways. The overall data demonstrated the great potential of the studied soil microbiome in the xenobiotic aromatics degradation. The results not only establish a rich reservoir for novel enzyme discovery but also provide putative applications in bioremediation. Copyright © 2016. Published by Elsevier B.V.

Factors that influence the speed of bacterial wood degradation

NARCIS (Netherlands)

Klaassen, R.K.W.M.; Overeem, van B.S.

2012-01-01

Bacterial wood decay is a serious threat to the many wooden foundation piles in the Netherlands. In order to learn more about the factors that influence the process of decay, approx. 2000 wood samples taken from Amsterdam piles heads were analysed on type and degree of decay and for 59 extracted

Preparation of Novel Fused Ring Spiro[benzotetraphene-fluorene] Derivatives and Application for Deep-Blue Host Materials

Energy Technology Data Exchange (ETDEWEB)

Kim, Minji; Lee, Chilwon; Gong, Myoungseon [Dankook Univ., Yongin (Korea, Republic of)

2014-06-15

A series of novel fused-ring spiro compounds, spiro[benzo[ij]tetraphene-7,9'-fluorene] derivatives containing an end-capping aryl substituent at both the C3 and C10-positions has been designed and synthesized via multi-step Suzuki coupling reactions. 3-(1-Naphthyl)-10-phenyl, 3-(2-naphthyl)-10-phenyl and 3-[4-(1-naphthyl)phenyl]-10-phenyl showed improved glass transition temperatures (T{sub g}) with good thermal stability. Their photophysical, electrochemical, and electroluminescent properties were investigated and were used to construct blue organic light emission diodes (OLEDs). The typical OLED devices showed excellent performance; the based device exhibited highly efficient deep blue-light emission with a maximum efficiency of 5.27 cd/A (EQE, 4.63%) with CIE (x = 0.133, y = 0.144). According to these characteristics, these deep-blue light emitting materials have sufficient potential for fluorescent OLED applications.

Characterization of dioxygenases and biosurfactants produced by crude oil degrading soil bacteria

Directory of Open Access Journals (Sweden)

Santhakumar Muthukamalam

Full Text Available ABSTRACT Role of microbes in bioremediation of oil spills has become inevitable owing to their eco friendly nature. This study focused on the isolation and characterization of bacterial strains with superior oil degrading potential from crude-oil contaminated soil. Three such bacterial strains were selected and subsequently identified by 16S rRNA gene sequence analysis as Corynebacterium aurimucosum, Acinetobacter baumannii and Microbacterium hydrocarbonoxydans respectively. The specific activity of catechol 1,2 dioxygenase (C12O and catechol 2,3 dioxygenase (C23O was determined in these three strains wherein the activity of C12O was more than that of C23O. Among the three strains, Microbacterium hydrocarbonoxydans exhibited superior crude oil degrading ability as evidenced by its superior growth rate in crude oil enriched medium and enhanced activity of dioxygenases. Also degradation of total petroleum hydrocarbon (TPH in crude oil was higher with Microbacterium hydrocarbonoxydans. The three strains also produced biosurfactants of glycolipid nature as indicated d by biochemical, FTIR and GCMS analysis. These findings emphasize that such bacterial strains with superior oil degrading capacity may find their potential application in bioremediation of oil spills and conservation of marine and soil ecosystem.

Perspectives of medium chain length poly(hydroxyalkanoates), a versatile set of bacterial bioplastics

Science.gov (United States)

Witholt; Kessler

1999-06-01

Medium chain length (mcl) poly(hydroxyalkanoic acids) (PHAs) are polyesters accumulated by fluorescent Pseudomonads and other bacteria. Work on the genetics of mcl-PHA formation has led to polymer synthesis in recombinant bacteria and plants. Several high and medium cost applications are now emerging. With optimized bacterial mcl-PHA synthesis on inexpensive agro-substrates and the development of plant-based mcl-PHAs in the next decade, the production economics of these bioplastics will ultimately permit their sustainable production for bulk applications.

Ecodynamics of oil-degrading bacteria and significance of marine mixed populations in the degradation of petroleum compounds

International Nuclear Information System (INIS)

Venkateswaran, Kasthuri; Tanaka, Hiroki; Komukai, Shyoko

1993-01-01

Ecological studies, screening of hydrocarbon-degrading bacteria, and studies of the potentials of various single and mixed bacterial populations in the utilization of petroleum compounds were carried out to understand the microbial hydrocarbon degradation process in marine ecosystems. Populations of hydrocarbon utilizers were larger in coastal regions than in pelagic environments. Ecological observations indicated that oil-degrading bacteria were ubiquitously distributed in both temperate and tropical environments, irrespective of oil-polluted and unpolluted ecosystem. Bacteria were grown with n-tet-radecane, pristane, propylbenzene, phenanthrene, and crude oil as the sole carbon source; and substrate specificities of the purified strains were characterized. Based on the assimilation characteristics of the isolated strains, an artificial mixed-culture system was constructed. Biodegradation of crude oil by the natural mixed population was found to be higher than by the artificial mixed population. However, when some of the substrate-specific degraders were artificially mixed with natural microflora, the degradation of hard-to-degrade aromatic hydrocarbon fractions of crude oil was enhanced

Novel salicylazo polymers for colon drug delivery: dissolving polymers by means of bacterial degradation.

Science.gov (United States)

Saphier, Sigal; Karton, Yishai

2010-02-01

Novel azo polymers were prepared for colonic drug delivery with a release mechanism based on structural features of azo derivatives designed for rapid bacterial degradation leading to soluble polymers. Two Salicylazo derivatives were prepared and conjugated as side chains at different ratios to methacrylic acid-methyl methacrylate copolymers (Eudragits). The azo compounds were designed to have a hydrophilic and a hydrophobic part on opposite sides of the azo bond. Upon reduction of the azo bonds, the hydrophobic part is released, resulting in a more water soluble polymer. The solubility of the polymeric films was studied relative to Eudragit S known to dissolve toward the end of the small intestine. One of the two azo derivatives prepared gave rise to polymers, which showed reduced solubility relative to Eudragit S. These polymers were subjected to reduction tests in anaerobic rat cecal suspensions by following the release of the hydrophobic product. Reduction rate was found to be rapid, comparable to that of Sulfasalazine. Studies on the azopolymeric films in anaerobic rat cecal suspensions, showed that these polymers dissolve faster than in sterilized suspensions. Solid dosage forms may be coated with these polymers to provide an efficient delivery system to the colon with a rapid release mechanism. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association.

Bacterial strategies of resistance to antimicrobial peptides.

Science.gov (United States)

Joo, Hwang-Soo; Fu, Chih-Iung; Otto, Michael

2016-05-26

Antimicrobial peptides (AMPs) are a key component of the host's innate immune system, targeting invasive and colonizing bacteria. For successful survival and colonization of the host, bacteria have a series of mechanisms to interfere with AMP activity, and AMP resistance is intimately connected with the virulence potential of bacterial pathogens. In particular, because AMPs are considered as potential novel antimicrobial drugs, it is vital to understand bacterial AMP resistance mechanisms. This review gives a comparative overview of Gram-positive and Gram-negative bacterial strategies of resistance to various AMPs, such as repulsion or sequestration by bacterial surface structures, alteration of membrane charge or fluidity, degradation and removal by efflux pumps.This article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. © 2016 The Author(s).

Bacterial community analysis in chlorpyrifos enrichment cultures via DGGE and use of bacterial consortium for CP biodegradation.

Science.gov (United States)

Akbar, Shamsa; Sultan, Sikander; Kertesz, Michael

2014-10-01

The organophosphate pesticide chlorpyrifos (CP) has been used extensively since the 1960s for insect control. However, its toxic effects on mammals and persistence in environment necessitate its removal from contaminated sites, biodegradation studies of CP-degrading microbes are therefore of immense importance. Samples from a Pakistani agricultural soil with an extensive history of CP application were used to prepare enrichment cultures using CP as sole carbon source for bacterial community analysis and isolation of CP metabolizing bacteria. Bacterial community analysis (denaturing gradient gel electrophoresis) revealed that the dominant genera enriched under these conditions were Pseudomonas, Acinetobacter and Stenotrophomonas, along with lower numbers of Sphingomonas, Agrobacterium and Burkholderia. Furthermore, it revealed that members of Bacteroidetes, Firmicutes, α- and γ-Proteobacteria and Actinobacteria were present at initial steps of enrichment whereas β-Proteobacteria appeared in later steps and only Proteobacteria were selected by enrichment culturing. However, when CP-degrading strains were isolated from this enrichment culture, the most active organisms were strains of Acinetobacter calcoaceticus, Pseudomonas mendocina and Pseudomonas aeruginosa. These strains degraded 6-7.4 mg L(-1) day(-1) of CP when cultivated in mineral medium, while the consortium of all four strains degraded 9.2 mg L(-1) day(-1) of CP (100 mg L(-1)). Addition of glucose as an additional C source increased the degradation capacity by 8-14 %. After inoculation of contaminated soil with CP (200 mg kg(-1)) disappearance rates were 3.83-4.30 mg kg(-1) day(-1) for individual strains and 4.76 mg kg(-1) day(-1) for the consortium. These results indicate that these organisms are involved in the degradation of CP in soil and represent valuable candidates for in situ bioremediation of contaminated soils and waters.

Manipulation of host membranes by bacterial effectors.

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Ham, Hyeilin; Sreelatha, Anju; Orth, Kim

2011-07-18

Bacterial pathogens interact with host membranes to trigger a wide range of cellular processes during the course of infection. These processes include alterations to the dynamics between the plasma membrane and the actin cytoskeleton, and subversion of the membrane-associated pathways involved in vesicle trafficking. Such changes facilitate the entry and replication of the pathogen, and prevent its phagocytosis and degradation. In this Review, we describe the manipulation of host membranes by numerous bacterial effectors that target phosphoinositide metabolism, GTPase signalling and autophagy.

Sphingomonas from petroleum-contaminated soils in Shenfu, China and their PAHs degradation abilities

Directory of Open Access Journals (Sweden)

Lisha Zhou

2016-06-01

Full Text Available Abstract Members of the Sphingomonas genus are often isolated from petroleum-contaminated soils due to their unique abilities to degrade polycyclic aromatic hydrocarbons (PAHs, which are important for in situ bioremediation. In this study, a combined phenotypic and genotypic approach using streptomycin-containing medium and Sphingomonas -specific PCR was developed to isolate and identify culturable Sphingomonas strains present in petroleum-contaminated soils in the Shenfu wastewater irrigation zone. Of the 15 soil samples examined, 12 soils yielded yellow streptomycin-resistant colonies. The largest number of yellow colony-forming units (CFUs could reach 105 CFUs g-1 soil. The number of yellow CFUs had a significant positive correlation (p < 0.05 with the ratio of PAHs to total petroleum hydrocarbons (TPH, indicating that Sphingomonas may play a key role in degrading the PAH fraction of the petroleum contaminants at this site. Sixty yellow colonies were selected randomly and analyzed by colony PCR using Sphingomonas -specific primers, out of which 48 isolates had PCR-positive signals. The 48 positive amplicons generated 8 distinct restriction fragment length polymorphism (RFLP patterns, and 7 out of 8 phylotypes were identified as Sphingomonas by 16S rRNA gene sequencing of the representative strains. Within these 7 Sphingomonas strains, 6 strains were capable of using fluorene as the sole carbon source, while 2 strains were phenanthrene-degrading Sphingomonas. To the best of our knowledge, this is the first report to evaluate the relationship between PAHs contamination levels and culturable Sphingomonas in environmental samples.

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

Corruption of innate immunity by bacterial proteases.

Science.gov (United States)

Potempa, Jan; Pike, Robert N

2009-01-01

The innate immune system of the human body has developed numerous mechanisms to control endogenous and exogenous bacteria and thus prevent infections by these microorganisms. These mechanisms range from physical barriers such as the skin or mucosal epithelium to a sophisticated array of molecules and cells that function to suppress or prevent bacterial infection. Many bacteria express a variety of proteases, ranging from non-specific and powerful enzymes that degrade many proteins involved in innate immunity to proteases that are extremely precise and specific in their mode of action. Here we have assembled a comprehensive picture of how bacterial proteases affect the host's innate immune system to gain advantage and cause infection. This picture is far from being complete since the numbers of mechanisms utilized are as astonishing as they are diverse, ranging from degradation of molecules vital to innate immune mechanisms to subversion of the mechanisms to allow the bacterium to hide from the system or take advantage of it. It is vital that such mechanisms are elucidated to allow strategies to be developed to aid the innate immune system in controlling bacterial infections.

Degradation of potassium rock by earthworms and responses of bacterial communities in its gut and surrounding substrates after being fed with mineral.

Science.gov (United States)

Liu, Dianfeng; Lian, Bin; Wang, Bin; Jiang, Guofang

2011-01-01

Earthworms are an ecosystem's engineers, contributing to a wide range of nutrient cycling and geochemical processes in the ecosystem. Their activities can increase rates of silicate mineral weathering. Their intestinal microbes usually are thought to be one of the key drivers of mineral degradation mediated by earthworms,but the diversities of the intestinal microorganisms which were relevant with mineral weathering are unclear. In this report, we show earthworms' effect on silicate mineral weathering and the responses of bacterial communities in their gut and surrounding substrates after being fed with potassium-bearing rock powder (PBRP). Determination of water-soluble and HNO(3)-extractable elements indicated some elements such as Al, Fe and Ca were significantly released from mineral upon the digestion of earthworms. The microbial communities in earthworms' gut and the surrounding substrates were investigated by amplified ribosomal DNA restriction analysis (ARDRA) and the results showed a higher bacterial diversity in the guts of the earthworms fed with PBRP and the PBRP after being fed to earthworms. UPGMA dendrogram with unweighted UniFrac analysis, considering only taxa that are present, revealed that earthworms' gut and their surrounding substrate shared similar microbiota. UPGMA dendrogram with weighted UniFrac, considering the relative abundance of microbial lineages, showed the two samples from surrounding substrate and the two samples from earthworms' gut had similarity in microbial community, respectively. Our results indicated earthworms can accelerate degradation of silicate mineral. Earthworms play an important role in ecosystem processe since they not only have some positive effects on soil structure, but also promote nutrient cycling of ecosystem by enhancing the weathering of minerals.

Degradation of potassium rock by earthworms and responses of bacterial communities in its gut and surrounding substrates after being fed with mineral.

Directory of Open Access Journals (Sweden)

Dianfeng Liu

Full Text Available BACKGROUND: Earthworms are an ecosystem's engineers, contributing to a wide range of nutrient cycling and geochemical processes in the ecosystem. Their activities can increase rates of silicate mineral weathering. Their intestinal microbes usually are thought to be one of the key drivers of mineral degradation mediated by earthworms,but the diversities of the intestinal microorganisms which were relevant with mineral weathering are unclear. METHODOLOGY/PRINCIPAL FINDINGS: In this report, we show earthworms' effect on silicate mineral weathering and the responses of bacterial communities in their gut and surrounding substrates after being fed with potassium-bearing rock powder (PBRP. Determination of water-soluble and HNO(3-extractable elements indicated some elements such as Al, Fe and Ca were significantly released from mineral upon the digestion of earthworms. The microbial communities in earthworms' gut and the surrounding substrates were investigated by amplified ribosomal DNA restriction analysis (ARDRA and the results showed a higher bacterial diversity in the guts of the earthworms fed with PBRP and the PBRP after being fed to earthworms. UPGMA dendrogram with unweighted UniFrac analysis, considering only taxa that are present, revealed that earthworms' gut and their surrounding substrate shared similar microbiota. UPGMA dendrogram with weighted UniFrac, considering the relative abundance of microbial lineages, showed the two samples from surrounding substrate and the two samples from earthworms' gut had similarity in microbial community, respectively. CONCLUSIONS/SIGNIFICANCE: Our results indicated earthworms can accelerate degradation of silicate mineral. Earthworms play an important role in ecosystem processe since they not only have some positive effects on soil structure, but also promote nutrient cycling of ecosystem by enhancing the weathering of minerals.

Isolation and characterization of two new methanesulfonic acid-degrading bacterial isolates from a Portuguese soil sample.

Science.gov (United States)

De Marco, P; Murrell, J C; Bordalo, A A; Moradas-Ferreira, P

2000-02-01

Two novel bacterial strains that can utilize methanesulfonic acid as a source of carbon and energy were isolated from a soil sample collected in northern Portugal. Morphological, physiological, biochemical and molecular biological characterization of the two isolates indicate that strain P1 is a pink-pigmented facultative methylotroph belonging to the genus Methylobacterium, while strain P2 is a restricted methylotroph belonging to the genus Hyphomicrobium. Both strains are strictly aerobic, degrade methanesulfonate, and release small quantities of sulfite into the medium. Growth on methanesulfonate induces a specific polypeptide profile in each strain. This, together with the positive hybridization to a DNA probe that carries the msm genes of Methylosulfonomonas methylovora strain M2, strongly endorses the contention that a methanesulfonic acid monooxygenase related to that found in the previously known methanesulfonate-utilizing bacteria is present in strains P1 and P2. The isolation of bacteria containing conserved msm genes from diverse environments and geographical locations supports the hypothesis that a common enzyme may be globally responsible for the oxidation of methanesulfonate by natural methylotrophic communities.

Distribution and life strategies of two bacterial populations in a eutrophic lake

Science.gov (United States)

Weinbauer; Hofle

1998-10-01

Monoclonal antibodies and epifluorescence microscopy were used to determine the depth distribution of two indigenous bacterial populations in the stratified Lake Plusssee and characterize their life strategies. Populations of Comamonas acidovorans PX54 showed a depth distribution with maximum abundances in the oxic epilimnion, whereas Aeromonas hydrophila PU7718 showed a depth distribution with maximum abundances in the anoxic thermocline layer (metalimnion), i. e., in the water layer with the highest microbial activity. Resistance of PX54 to protist grazing and high metabolic versatility and growth rate of PU7718 were the most important life strategy traits for explaining the depth distribution of the two bacterial populations. Maximum abundance of PX54 was 16,000 cells per ml, and maximum abundance of PU7718 was 20,000 cells per ml. Determination of bacterial productivity in dilution cultures with different-size fractions of dissolved organic matter (DOM) from lake water indicates that low-molecular-weight (LMW) DOM is less bioreactive than total DOM (TDOM). The abundance and growth rate of PU7718 were highest in the TDOM fractions, whereas those of PX54 were highest in the LMW DOM fraction, demonstrating that PX54 can grow well on the less bioreactive DOM fraction. We estimated that 13 to 24% of the entire bacterial community and 14% of PU7718 were removed by viral lysis, whereas no significant effect of viral lysis on PX54 could be detected. Growth rates of PX54 (0.11 to 0.13 h-1) were higher than those of the entire bacterial community (0.04 to 0.08 h-1) but lower than those of PU7718 (0.26 to 0.31 h-1). In undiluted cultures, the growth rates were significantly lower, pointing to density effects such as resource limitation or antibiosis, and the effects were stronger for PU7718 and the entire bacterial community than for PX54. Life strategy characterizations based on data from literature and this study revealed that the fast-growing and metabolically

Characterization of acetanilide herbicides degrading bacteria isolated from tea garden soil.

Science.gov (United States)

Wang, Yei-Shung; Liu, Jian-Chang; Chen, Wen-Ching; Yen, Jui-Hung

2008-04-01

Three different green manures were added to the tea garden soils separately and incubated for 40 days. After, incubation, acetanilide herbicides alachlor and metolachlor were spiked into the soils, separately, followed by the isolation of bacteria in each soil at designed intervals. Several bacterial strains were isolated from the soils and identified as Bacillus silvestris, B. niacini, B. pseudomycoides, B. cereus, B. thuringiensis, B. simplex, B. megaterium, and two other Bacillus sp. (Met1 and Met2). Three unique strains with different morphologies were chosen for further investigation. They were B. megaterium, B. niacini, and B. silvestris. The isolated herbicide-degrading bacteria showed optimal performance among three incubation temperatures of 30 degrees C and the best activity in the 10 to 50 microg/ml concentration of the herbicide. Each bacterial strain was able to degrade more than one kind of test herbicides. After incubation for 119 days, B. cereus showed the highest activity to degrade alachlor and propachlor, and B. thuringiensis to degrade metolachlor.

Versatile radiation gaging system

International Nuclear Information System (INIS)

Long, P.J.

1978-01-01

The attributes of computerized versatile radiation gaging systems are described. The gages are used to measure plating thicknesses and material characteristics that can be determined from radiation attenuation and/or x-ray fluorescence measurements

Degradation of corn stalk by the composite microbial system of MC1

Institute of Scientific and Technical Information of China (English)

无

2008-01-01

The composite microbial system of MC1 was used to degrade corn stalk in order to determine properties of the degraded products as well as bacterial composition of MC1. Results indicated that the pH of the fermentation broth was typical of lignocellulose degradatioin by MC1, decreasing in the early phase and increasing in later stages of the degradation. The microbial biomass peaked on the day 3 after degradation. The MC1 effeciently degraded the corn stalk by nearly 70% during which its cellulose content decreased by 71.2%, hemicellulose by 76.5% and lignin by 24.6%. The content of water-soluble carbohydrates (WSC) in the fermentation broth increased progressively during the first three days, and decreased thereafter, suggesting an accumulation of WSC in the early phase of the degradation process. Total levels of various volatile products peaked in the third day after degradation , and 7 types of volatile products were detected in the fermentation broth. These were ethanol, acetic acid, 1,2-ethanediol, propanoic acid, butanoic acid, 3-methyl-butanoic acid and glycerine. Six major compounds were quantitatively analysed and the contents of each compound were ethanol (0.584 g/L), acetic acid (0.735 g/L), 1,2-ethanediol (0.772 g/L), propanoic acid (0.026 g/L), butanoic acid (0.018 g/L) and glycerine (4.203 g/L). Characterization of bacterial cells collected from the culture solution, based on 16S rDNA PCR-DGGE analysis of DNAs, showed that the composition of bacterial community in MC1 coincided basically with observations from previous studies. This indicated that the structure of MC1 is very stable during degradation of different lignocellulose materials.

Use of mycelia as paths for the isolation of contaminant‐degrading bacteria from soil

Science.gov (United States)

Furuno, Shoko; Remer, Rita; Chatzinotas, Antonis; Harms, Hauke; Wick, Lukas Y.

2012-01-01

Summary Mycelia of fungi and soil oomycetes have recently been found to act as effective paths boosting bacterial mobility and bioaccessibility of contaminants in vadose environments. In this study, we demonstrate that mycelia can be used for targeted separation and isolation of contaminant‐degrading bacteria from soil. In a ‘proof of concept’ study we developed a novel approach to isolate bacteria from contaminated soil using mycelia of the soil oomycete Pythium ultimum as translocation networks for bacteria and the polycyclic aromatic hydrocarbon naphthalene (NAPH) as selective carbon source. NAPH‐degrading bacterial isolates were affiliated with the genera Xanthomonas, Rhodococcus and Pseudomonas. Except for Rhodococcus the NAPH‐degrading isolates exhibited significant motility as observed in standard swarming and swimming motility assays. All steps of the isolation procedures were followed by cultivation‐independent terminal 16S rRNA gene terminal fragment length polymorphism (T‐RFLP) analysis. Interestingly, a high similarity (63%) between both the cultivable NAPH‐degrading migrant and the cultivable parent soil bacterial community profiles was observed. This suggests that mycelial networks generally confer mobility to native, contaminant‐degrading soil bacteria. Targeted, mycelia‐based dispersal hence may have high potential for the isolation of bacteria with biotechnologically useful properties. PMID:22014110

Micropollutant degradation, bacterial inactivation and regrowth risk in wastewater effluents: Influence of the secondary (pre)treatment on the efficiency of Advanced Oxidation Processes.

Science.gov (United States)

Giannakis, Stefanos; Voumard, Margaux; Grandjean, Dominique; Magnet, Anoys; De Alencastro, Luiz Felippe; Pulgarin, César

2016-10-01

In this work, disinfection by 5 Advanced Oxidation Processes was preceded by 3 different secondary treatment systems present in the wastewater treatment plant of Vidy, Lausanne (Switzerland). 5 AOPs after two biological treatment methods (conventional activated sludge and moving bed bioreactor) and a physiochemical process (coagulation-flocculation) were tested in laboratory scale. The dependence among AOPs efficiency and secondary (pre)treatment was estimated by following the bacterial concentration i) before secondary treatment, ii) after the different secondary treatment methods and iii) after the various AOPs. Disinfection and post-treatment bacterial regrowth were the evaluation indicators. The order of efficiency was Moving Bed Bioreactor > Activated Sludge > Coagulation-Flocculation > Primary Treatment. As far as the different AOPs are concerned, the disinfection kinetics were: UVC/H2O2 > UVC and solar photo-Fenton > Fenton or solar light. The contextualization and parallel study of microorganisms with the micropollutants of the effluents revealed that higher exposure times were necessary for complete degradation compared to microorganisms for the UV-based processes and inversed for the Fenton-related ones. Nevertheless, in the Fenton-related systems, the nominal 80% removal of micropollutants deriving from the Swiss legislation, often took place before the elimination of bacterial regrowth risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evolution of bacterial community during bioremediation of PAHs in a coal tar contaminated soil

Energy Technology Data Exchange (ETDEWEB)

Lors, C.; Ryngaert, A.; Perie, F.; Diels, L.; Damidot, D. [University of Lille, Lille (France)

2010-11-15

The monitoring of a windrow treatment applied to soil contaminated by mostly 2, 3- and 4-ring PAHs produced by coal tar distillation was performed by following the evolution of both PAH concentration and the bacterial community. Total and PAH-degrading bacterial community structures were followed by 165 rRNA PCR-DGGE in parallel with quantification by bacterial counts and 16 PAH measurements. Six months of biological treatment led to a strong decrease in 2-, 3- and 4-ring PAH concentrations (98, 97 and 82%, respectively). This result was associated with the activity of bacterial PAH-degraders belonging mainly to the Gamma proteobacteria, in particular the Enterobacteria and Pseudomonas genera which were detected over the course of the treatment. This group was considered to be a good bioindicator to determine the potential PAH biodegradation of contaminated soil. Conversely other species like the Beta proteobacteria were detected after 3 months when 2-, 3- and 4-ring PAHs were almost completely degraded. Thus presence of the Beta proteobacteria group could be considered a good candidate indicator to estimate the endpoint of biotreatment of this type of PAH contaminated soil.

A microcosm approach to evaluate the degradation of tributyltin (TBT) by Aeromonas molluscorum Av27 in estuarine sediments.

Science.gov (United States)

Cruz, Andreia; Henriques, Isabel; Sousa, Ana C A; Baptista, Inês; Almeida, Adelaide; Takahashi, Shin; Tanabe, Shinsuke; Correia, António; Suzuki, Satoru; Anselmo, Ana Maria; Mendo, Sónia

2014-07-01

Tributyltin (TBT) is a biocide extremely toxic to a wide range of organisms, which has been used for decades in antifouling paints. Despite its global ban in 2008, TBT is still a problem of great concern due to the high levels trapped in sediments. Aeromonas molluscorum Av27 is a TBT degrading bacterium that was isolated from an estuarine system. We investigated the ability and the role of this bacterium on TBT degradation in this estuarine system, using a microcosm approach in order to mimic environmental conditions. The experiment was established and followed for 150 days. Simultaneously, changes in the indigenous bacterial community structure were also investigated. The results revealed a maximum TBT degradation rate of 28% accompanied by the detection of the degradation products over time. Additionally, it was observed that TBT degradation was significantly enhanced by the presence of Av27. In addition a significantly higher TBT degradation occurred when the concentration of Av27 was higher. TBT degradation affected the bacterial community composition as revealed by the changes in the prevalence of Proteobacteria subdivisions, namely the increase of Deltaproteobacteria and the onset of Epsilonproteobacteria. However, the addition of Av27 strain did not affect the dominant phylotypes. Total bacterial number, bacterial biomass productivity, 16S rRNA gene and denaturing gradient gel electrophoresis (DGGE) analyses also indicated alterations on the bacterial community structure over time, with bacteria non-tolerant to pollutants increasing their representativeness, as, for instance, the increase of the number of Alphaproteobacteria clones from 6% in the beginning to 12% at the end of the experiment. The work herein presented confirms the potential of Av27 strain to be used in the decontamination of TBT-polluted environments. Copyright © 2014 Elsevier Inc. All rights reserved.

High-Throughput Screening for a Moderately Halophilic Phenol-Degrading Strain and Its Salt Tolerance Response

Science.gov (United States)

Lu, Zhi-Yan; Guo, Xiao-Jue; Li, Hui; Huang, Zhong-Zi; Lin, Kuang-Fei; Liu, Yong-Di

2015-01-01

A high-throughput screening system for moderately halophilic phenol-degrading bacteria from various habitats was developed to replace the conventional strain screening owing to its high efficiency. Bacterial enrichments were cultivated in 48 deep well microplates instead of shake flasks or tubes. Measurement of phenol concentrations was performed in 96-well microplates instead of using the conventional spectrophotometric method or high-performance liquid chromatography (HPLC). The high-throughput screening system was used to cultivate forty-three bacterial enrichments and gained a halophilic bacterial community E3 with the best phenol-degrading capability. Halomonas sp. strain 4-5 was isolated from the E3 community. Strain 4-5 was able to degrade more than 94% of the phenol (500 mg·L−1 starting concentration) over a range of 3%–10% NaCl. Additionally, the strain accumulated the compatible solute, ectoine, with increasing salt concentrations. PCR detection of the functional genes suggested that the largest subunit of multicomponent phenol hydroxylase (LmPH) and catechol 1,2-dioxygenase (C12O) were active in the phenol degradation process. PMID:26020478

Crude oil degradation by bacterial consortia under four different redox and temperature conditions.

Science.gov (United States)

Xiong, Shunzi; Li, Xia; Chen, Jianfa; Zhao, Liping; Zhang, Hui; Zhang, Xiaojun

2015-02-01

There is emerging interest in the anaerobic degradation of crude oil. However, there is limited knowledge about the geochemical effects and microbiological activities for it. A mixture of anaerobic sludge and the production water from an oil well was used as an inoculum to construct four consortia, which were incubated under sulfate-reducing or methanogenic conditions at either mesophilic or thermophilic temperatures. Significant degradation of saturated and aromatic hydrocarbons and the changing quantities of some marker compounds, such as pristane, phytane, hopane and norhopane, and their relative quantities, suggested the activity of microorganisms in the consortia. Notably, the redox conditions and temperature strongly affected the diversity and structure of the enriched microbial communities and the oil degradation. Although some specific biomarker showed larger change under methanogenic condition, the degradation efficiencies for total aromatic and saturated hydrocarbon were higher under sulfate-reducing condition. After the 540-day incubation, bacteria of unknown classifications were dominant in the thermophilic methanogenic consortia, whereas Clostridium dominated the mesophilic methanogenic consortia. With the exception of the dominant phylotypes that were shared with the methanogenic consortia, the sulfate-reducing consortia were predominantly composed of Thermotogae, Deltaproteobacteria, Spirochaeta, and Synergistetes phyla. In conclusion, results in this study demonstrated that the different groups of degraders were responsible for degradation in the four constructed crude oil degrading consortia and consequently led to the existence of different amount of marker compounds under these distinct conditions. There might be distinct metabolic mechanism for degrading crude oil under sulfate-reducing and methanogenic conditions.

Effects of bacterial inoculation on the fermentation characteristics ...

African Journals Online (AJOL)

DNkosi

2016-05-11

May 11, 2016 ... The chopped forages were treated with or without the bacterial .... packed loosely in an open plastic jar, which was covered with two ..... be because LD inoculant contains enzymes that may be capable of degrading fibre.

Assessment of Bacterial Degradation of Aromatic Hydrocarbons in the Environment by Analysis of Stable Carbon Isotope Fractionation

International Nuclear Information System (INIS)

Meckenstock, Rainer U.; Morasch, Barbara; Kaestner, Matthias; Vieth, Andrea; Richnow, Hans Hermann

2002-01-01

13 C/ 12 C stable carbon isotope fractionation was used to assess biodegradation in contaminated aquifers with toluene as a model compound. Different strains of anaerobic bacteria (Thauera aromatica, Geobacter metallireducens, and the sulfate-reducing strain TRM1) showed consistent 13 C/ 12 C carbon isotope fractionation with fractionation factors between αC = 1.0017 and 1.0018. In contrast, three cultures of aerobic organisms, using different mono- and dioxygenase enzyme systems to initiate toluene degradation, showed variable isotope fractionation factors of αC = 1.0027 (Pseudomonasputida strain mt-2), αC = 1.0011 (Ralstonia picketii), andαC = 1.0004 (Pseudomonas putida strain F1). The great variability of isotope fractionation between different aerobic bacterial strains suggests that interpretation of isotope data in oxic habitats can only be qualitative. A soil column was run as a model system for contaminated aquifers with toluene as the carbon source and sulfate as the electron acceptor and samples were taken at different ports along the column. Microbial toluene degradation was calculated based on the 13 C/ 12 C isotope fractionation factors of the batch culture experiments together with the observed 13 C/ 12 C isotope shifts of the residual toluene fractions. The calculated percentage of biodegradation, B, correlated well with the decreasing toluene concentrations at the sampling ports and indicated the increasing extent of biodegradation along the column. The theoretical toluene concentrations as calculated based on the isotope values matched the measured concentrations at the different sampling ports indicating that the Rayleigh equation can be used to calculate biodegradation in quasi closed systems based on measured isotope shifts. A similar attempt was performed to assess toluene degradation in a contaminated, anoxic aquifer. A transect of groundwater wells was monitored along the main direction of the groundwater flow and revealed decreasing

Identification of New Aflatoxin B1-Degrading Bacteria from Iran

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Fahimeh Sangi

2018-04-01

Full Text Available Background: Aflatoxin B1 (AFB1 is a mutagenic and carcinogenic compound mainly produced by the Aspergillus parasiticus, A. flavus, A. nomius, A. tamari, and A. pseudotamarii. AFB1 biodegradation is the most important strategy for reducing AFB1 in plant tissues. Bacteria can deactivate and biodegrade AFB1 for effective detoxification of contaminated products. The present study investigated the efficiency of AFB1 degradation by soil bacteria from the Southern Khorasan Province in Eastern Iran by thin-layer and high-performance liquid chromatography during 2014–2015. Methods: DNA was extracted from AFB1-degrading isolates by the cetyltrimethylammonium bromide method and the 16S rRNA gene was amplified with the 27f and 1492r general bacterial primers and the sequences were used to identify the isolates based on their similarity to Gene Bank sequences of known bacterial species. Results: We isolated five strains from four species of AFB1-degrading bacteria from Birjand plain, including Bacillus pumilus, two isolates of Ochrobactrum pseudogrigonens, Pseudomonas aeruginosa, and Enterobacter cloace, which had AFB1-degrading activities of 88%, 78%, 61%, 58%, and 51%, respectively. Conclusion: We provide the first demonstration of AFB1 degradation by B. pumilus in from Iran and the first report identifying O. pseudogrigonens and E. cloace species as having AFB1-degrading activity.

Degradation of polycyclic aromatic hydrocarbons by microbial consortia enriched from three soils using two different culture media.

Science.gov (United States)

Wu, Manli; Chen, Liming; Tian, Yongqiang; Ding, Yi; Dick, Warren A

2013-07-01

A consortium composed of many different bacterial species is required to efficiently degrade polycyclic aromatic hydrocarbons (PAH) in oil-contaminated soil. We obtained six PAH-degrading microbial consortia from three oil-contaminated soils using two different isolation culture media. Denaturing gradient gel electrophoresis (DGGE) and sequence analyses of amplified 16s rRNA genes confirmed the bacterial community was greatly affected by both the culture medium and the soil from which the consortia were enriched. Three bacterial consortia enriched using malt yeast extract (MYE) medium showed higher degradation rates of PAHs than consortia enriched using Luria broth (LB) medium. Consortia obtained from a soil and then added back to that same soil was more effective in degrading PAHs than adding, to the same soil, consortia isolated from other, unrelated soils. This suggests that inoculum used for bioremediation should be from the same, or very similar nearby soils, as the soil that is actually being bioremediated. Copyright © 2013 Elsevier Ltd. All rights reserved.

Degradation of polycyclic aromatic hydrocarbons by microbial consortia enriched from three soils using two different culture media

International Nuclear Information System (INIS)

Wu, Manli; Chen, Liming; Tian, Yongqiang; Ding, Yi; Dick, Warren A.

2013-01-01

A consortium composed of many different bacterial species is required to efficiently degrade polycyclic aromatic hydrocarbons (PAH) in oil-contaminated soil. We obtained six PAH-degrading microbial consortia from three oil-contaminated soils using two different isolation culture media. Denaturing gradient gel electrophoresis (DGGE) and sequence analyses of amplified 16s rRNA genes confirmed the bacterial community was greatly affected by both the culture medium and the soil from which the consortia were enriched. Three bacterial consortia enriched using malt yeast extract (MYE) medium showed higher degradation rates of PAHs than consortia enriched using Luria broth (LB) medium. Consortia obtained from a soil and then added back to that same soil was more effective in degrading PAHs than adding, to the same soil, consortia isolated from other, unrelated soils. This suggests that inoculum used for bioremediation should be from the same, or very similar nearby soils, as the soil that is actually being bioremediated. -- Highlights: •Six PAH-degrading microbial consortia were isolated from three oil-contaminated soils. •The bacterial community by 16s rRNA genes was affected by culture media and source soil. •Inoculum should be from the same or similar soil as the soil being bioremediated. -- Bioremediation of oil-contaminated soils was most effective when using inoculum of microbial consortia from the same or similar soil as the soil being bioremediated

Effects of Biological and Photochemical Degradation on the Optical Properties of CDOM Exported to Coastal Marine Environments

National Research Council Canada - National Science Library

Moran, Mary

2004-01-01

.... This project quantitatively assessed the ability of coastal ocean bacteria to degrade and produce CDOM and investigated the synergistic interactions between bacterial degradation and photochemical...

Bacterial inoculum enhances keratin degradation and biofilm formation in poultry compost.

Science.gov (United States)

Ichida, J M; Krizova, L; LeFevre, C A; Keener, H M; Elwell, D L; Burtt, E H

2001-11-01

Native microbial populations can degrade poultry waste, but the process can be hastened by using feather-degrading bacteria. Strains of Bacillus licheniformis and a Streptomyces sp. isolated from the plumage of wild birds were grown in a liquid basal medium and used to inoculate feathers in compost bioreaction vessels. Control vessels had only basal medium added to the feathers, litter and straw. Temperature, ammonia, carbon and nitrogen were monitored for 4 weeks. Scanning electron microscopy of the feather samples showed more complete keratin-degradation, more structural damage, and earlier microbial biofilm formation on inoculated feathers than on uninoculated feathers. A diverse community of aerobic bacteria and fungi were cultured early, but declined rapidly. Thermophilic B. licheniformis and Streptomyces spp. were abundant throughout. Enteric gram-negative bacteria, (e.g., Salmonella, E. coli) originally found on waste feathers were not recovered after day 4. Vessel temperatures reached 64-71 degrees C within 36 h and stabilized at 50 degrees C. When tumble-mixed at day 14, renewed activity peaked at 59 degrees C and quickly dropped as available carbon was used. Feathers soaked in an inoculum of B. licheniformis and Streptomyces degraded more quickly and more completely than feathers that were not presoaked. Inoculation of feather waste could improve composting of the large volume of feather waste generated every year by poultry farms and processing plants.

Characterization of resistant tomato mutants to bacterial canker ...

African Journals Online (AJOL)

Yomi

2012-04-19

Apr 19, 2012 ... Cmm bacteria induce bacterial canker and wilt during infection. It is unknown ... are able to degrade plant cell walls and attack xylem vessels and ... seedlings were transferred into plastic pots at four to five true leaf stages.

Degradation of petroleum hydrocarbons by oil field isolated bacterial ...

African Journals Online (AJOL)

A mixed consortium was prepared with 15 bacteria isolated by enrichment technique from the sample collected from an oil contaminated site. This consortium was incubated with crude oil to investigate the metabolic capability of bacteria. The degradation efficiency of the isolates in consortium was checked with 2% crude oil ...

Dynamic changes of bacterial community under bioremediation with Sphingobium sp. LY-6 in buprofezin-contaminated soil.

Science.gov (United States)

Liu, Yuan; Hou, Qianqian; Liu, Wanru; Meng, Yawen; Wang, Guangli

2015-08-01

Buprofezin is a commonly used chemical with satisfactory biological activity against sucking insect pests, but its disposal can cause serious environmental problems. To study the feasibility of remedying contamination by buprofezin, microcosm experiments were carried out to study the effects of various concentrations of buprofezin and Sphingobium sp. LY-6 on soil bacterial communities in soils collected from vegetable fields. In this experiment, the results showed that buprofezin was effectively degraded by Sphingobium sp. LY-6 in incubation soils. Comparing to non-incubated soils, the cumulative degradation ratio of buprofezin was significantly increased, up to the extent of 85 and 51%, in the initial concentration of 10 and 100 mg kg(-1). The abundance and community structure of the bacterial communities were analysed by real-time PCR (qPCR) and terminal-restriction fragment length polymorphism (T-RFLP). The findings suggest that buprofezin had a negative effect on soil bacterial community, and decreases in bacterial abundance were observed in the later part of the incubation period. The bacterial community structure and diversity shifted significantly at each sampling time. In conclusion, the buprofezin-degrading strain LY-6 played a major role in the bioremediation of the buprofezin-contaminated soil and influenced the dynamics and structure of the bacterial community, demonstrating the great potential of exogenous microorganisms for soil remediation.

Biodegradation of petroleum hydrocarbons in seawater at low temperatures (0-5 degrees C) and bacterial communities associated with degradation.

Science.gov (United States)

Brakstad, Odd G; Bonaunet, Kristin

2006-02-01

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

In-Field Spatial Variability in the Degradation of the Phenyl-Urea Herbicide Isoproturon Is the Result of Interactions between Degradative Sphingomonas spp. and Soil pH

Science.gov (United States)

Bending, Gary D.; Lincoln, Suzanne D.; Sørensen, Sebastian R.; Morgan, J. Alun W.; Aamand, Jens; Walker, Allan

2003-01-01

Substantial spatial variability in the degradation rate of the phenyl-urea herbicide isoproturon (IPU) [3-(4-isopropylphenyl)-1,1-dimethylurea] has been shown to occur within agricultural fields, with implications for the longevity of the compound in the soil, and its movement to ground- and surface water. The microbial mechanisms underlying such spatial variability in degradation rate were investigated at Deep Slade field in Warwickshire, United Kingdom. Most-probable-number analysis showed that rapid degradation of IPU was associated with proliferation of IPU-degrading organisms. Slow degradation of IPU was linked to either a delay in the proliferation of IPU-degrading organisms or apparent cometabolic degradation. Using enrichment techniques, an IPU-degrading bacterial culture (designated strain F35) was isolated from fast-degrading soil, and partial 16S rRNA sequencing placed it within the Sphingomonas group. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified bacterial community 16S rRNA revealed two bands that increased in intensity in soil during growth-linked metabolism of IPU, and sequencing of the excised bands showed high sequence homology to the Sphingomonas group. However, while F35 was not closely related to either DGGE band, one of the DGGE bands showed 100% partial 16S rRNA sequence homology to an IPU-degrading Sphingomonas sp. (strain SRS2) isolated from Deep Slade field in an earlier study. Experiments with strains SRS2 and F35 in soil and liquid culture showed that the isolates had a narrow pH optimum (7 to 7.5) for metabolism of IPU. The pH requirements of IPU-degrading strains of Sphingomonas spp. could largely account for the spatial variation of IPU degradation rates across the field. PMID:12571001

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

In vitro chondrogenesis with lysozyme susceptible bacterial cellulose as a scaffold.

Science.gov (United States)

Yadav, Vikas; Sun, Lin; Panilaitis, Bruce; Kaplan, David L

2015-12-01

A current focus of tissue engineering is the use of adult human mesenchymal stem cells (hMSCs) as an alternative to autologous chondrocytes for cartilage repair. Several natural and synthetic polymers (including cellulose) have been explored as a biomaterial scaffold for cartilage tissue engineering. While bacterial cellulose (BC) has been used in tissue engineering, its lack of degradability in vivo and high crystallinity restricts widespread applications in the field. Recently we reported the formation of a novel bacterial cellulose that is lysozyme-susceptible and -degradable in vivo from metabolically engineered Gluconacetobacter xylinus. Here we report the use of this modified bacterial cellulose (MBC) for cartilage tissue engineering using hMSCs. MBC's glucosaminoglycan-like chemistry, combined with in vivo degradability, suggested opportunities to exploit this novel polymer in cartilage tissue engineering. We have observed that, like BC, MBC scaffolds support cell attachment and proliferation. Chondrogenesis of hMSCs in the MBC scaffolds was demonstrated by real-time RT-PCR analysis for cartilage-specific extracellular matrix (ECM) markers (collagen type II, aggrecan and SOX9) as well as histological and immunohistochemical evaluations of cartilage-specific ECM markers. Further, the attachment, proliferation, and differentiation of hMSCs in MBC showed unique characteristics. For example, after 4 weeks of cultivation, the spatial cell arrangement and collagen type-II and ACAN distribution resembled those in native articular cartilage tissue, suggesting promise for these novel in vivo degradable scaffolds for chondrogenesis. Copyright © 2013 John Wiley & Sons, Ltd.

Multiple cellobiohydrolases and cellobiose phosphorylases cooperate in the ruminal bacterium Ruminococcus albus 8 to degrade cellooligosaccharides.

Science.gov (United States)

Devendran, Saravanan; Abdel-Hamid, Ahmed M; Evans, Anton F; Iakiviak, Michael; Kwon, In Hyuk; Mackie, Roderick I; Cann, Isaac

2016-10-17

Digestion of plant cell wall polysaccharides is important in energy capture in the gastrointestinal tract of many herbivorous and omnivorous mammals, including humans and ruminants. The members of the genus Ruminococcus are found in both the ruminant and human gastrointestinal tract, where they show versatility in degrading both hemicellulose and cellulose. The available genome sequence of Ruminococcus albus 8, a common inhabitant of the cow rumen, alludes to a bacterium well-endowed with genes that target degradation of various plant cell wall components. The mechanisms by which R. albus 8 employs to degrade these recalcitrant materials are, however, not clearly understood. In this report, we demonstrate that R. albus 8 elaborates multiple cellobiohydrolases with multi-modular architectures that overall enhance the catalytic activity and versatility of the enzymes. Furthermore, our analyses show that two cellobiose phosphorylases encoded by R. albus 8 can function synergistically with a cognate cellobiohydrolase and endoglucanase to completely release, from a cellulosic substrate, glucose which can then be fermented by the bacterium for production of energy and cellular building blocks. We further use transcriptomic analysis to confirm the over-expression of the biochemically characterized enzymes during growth of the bacterium on cellulosic substrates compared to cellobiose.

Mathematical Modelling of Bacterial Populations in Bio-remediation Processes

Science.gov (United States)

Vasiliadou, Ioanna A.; Vayenas, Dimitris V.; Chrysikopoulos, Constantinos V.

2011-09-01

An understanding of bacterial behaviour concerns many field applications, such as the enhancement of water, wastewater and subsurface bio-remediation, the prevention of environmental pollution and the protection of human health. Numerous microorganisms have been identified to be able to degrade chemical pollutants, thus, a variety of bacteria are known that can be used in bio-remediation processes. In this study the development of mathematical models capable of describing bacterial behaviour considered in bio-augmentation plans, such as bacterial growth, consumption of nutrients, removal of pollutants, bacterial transport and attachment in porous media, is presented. The mathematical models may be used as a guide in designing and assessing the conditions under which areas contaminated with pollutants can be better remediated.

Taxonomical analysis of the suspended bacterial fraction in the ...

African Journals Online (AJOL)

ajl yemi

2011-11-30

Nov 30, 2011 ... hundred individuals representative of the rumen bacterial community. A preliminary analysis ... sterile plastic syringes from eviscerated animals. The fluid was .... engaged in the active degradation of the substrate to which as a ...

Structured attachment of bacterial molecular motors for defined microflow induction

Directory of Open Access Journals (Sweden)

Woerdemann Mike

2014-01-01

Full Text Available Bacterial rotational motor complexes that propel flagellated bacteria possess unique properties like their size of a few nanometres and the ability of selfreproduction that have led to various exciting applications including biohybrid nano-machines. One mandatory prerequisite to utilize bacterial nano motors in fluid applications is the ability to transfer force and torque to the fluid, which usually can be achieved by attachment of the bacterial cell to adequate surfaces. Additionally, for optimal transfer of force or torque, precise control of the position down to the single cell level is of utmost importance. Based on a PIV (particle image velocimetry evaluation of the induced flow of single bacteria,we propose and demonstrate attachment of arbitrary patterns of motile bacterial cells in a fast light-based two-step process for the first time to our knowledge. First, these cells are pre-structured by holographic optical tweezers and then attached to a homogeneous, polystyrene-coated surface. In contrast to the few approaches that have been implemented up to now and which rely on pre-structured surfaces, our scheme allows for precise control on a single bacterium level, is versatile, interactive and has low requirements with respect to the surface preparation.

[Isolation, identification and characterization of a diethylstilbestrol-degrading bacterial strain Serratia sp].

Science.gov (United States)

Xu, Ran-Fang; Sun, Min-Xia; Liu, Juan; Wang, Hong; Li, Xin; Zhu, Xue-Zhu; Ling, Wan-Ting

2014-08-01

Utilizing the diethylstilbestrol (DES)-degrading bacteria to biodegrade DES is a most reliable technique for cleanup of DES pollutants from the environment. However, little information is available heretofore on the isolation of DES-degrading bacteria and their DES removal performance in the environment. A novel bacterium capable of degrading DES was isolated from the activated sludge of a wastewater treatment plant. According to its morphology, physiochemical characteristics, and 16S rDNA sequence analysis, this strain was identified as Serratia sp.. The strain was an aerobic bacterium, and it could degrade 68.3% of DES (50 mg x L(-1)) after culturing for 7 days at 30 degrees C, 150 r x min(-1) in shaking flasks. The optimal conditions for DES biodegradation by the obtained strain were 30 degrees C, 40-60 mg x L(-1) DES, pH 7.0, 5% of inoculation volume, 0 g x L(-1) of added NaCl, and 10 mL of liquid medium volume in 100 mL flask.

Selection of bacteria with hydrocarbon degrading capacity isolated from Colombian Caribbean sediments

International Nuclear Information System (INIS)

Narvaez Florez, Silvia; Gomez, Martha L; Martinez Maria M

2008-01-01

Thirty one bacterial isolations in minimal salts supplemented medium with hydrocarbons (ACPM or crude oil) as sole carbon source were isolated from sediment samples from the Colombian Caribbean. Bacterial strains underwent selection tests in different concentrations of hydrocarbons; 11 tolerant crude oil and ACPM strains in a range of 1-8%v/v were chosen. A mixed bacterial culture was created and assessed its ability to degrade hydrocarbons in a laboratory-scale test, with a concentration of 2% v/v of ACPM over a period of 21 days. Measurements of biomass in Colony Forming Units (CFU)/mL were used to develop the growth curve of the mixed culture. Hydrocarbons remotion was measured by mass chromatography. The mixed culture was able to degrade the 68.6% of aliphatic hydrocarbons in preference of long chain n- alkenes (C12- C31), reaching a maximum growth of 3.13 x 10 9 UFC / mL. Degradation of aromatic hydrocarbons was not evidenced under the observation time. Nine of the eleven strains were identified using the biochemical systems BBL and API 50 CHB/E; they belonged to the genus Klebsiella, Chromobacterium, Flavimonas, Enterobacter,Pseudomonas, and Bacillus. The evaluated strains have enzymatic potential to degrade hydrocarbons and it is necessary to characterize them at molecular level in order to develop and effective consortium for field application

Characterization of TEMPO-oxidized bacterial cellulose

International Nuclear Information System (INIS)

Nascimento, Eligenes S.; Pereira, Andre L.S.; Lima, Helder L.; Barroso, Maria K. de A.; Barros, Matheus de O.; Morais, Joao P.S.; Borges, Maria de F.; Rosa, Morsyleide de F.

2015-01-01

The aim of this study was to characterize the TEMPO-oxidized bacterial cellulose, as a preliminary research for further application in nanocomposites. Bacterial cellulose (BC) was selectively oxidized at C-6 carbon by TEMPO radical. Oxidized bacterial cellulose (BCOX) was characterized by TGA, FTIR, XRD, and zeta potential. BCOX suspension was stable at pH 7.0, presented a crystallinity index of 83%, in spite of 92% of BC, because of decrease in the free hydroxyl number. FTIR spectra showed characteristic BC bands and, in addition, band of carboxylic group, proving the oxidation. BCOX DTG showed, in addition to characteristic BC thermal events, a maximum degradation peak at 233 °C, related to sodium anhydro-glucuronate groups formed during the cellulose oxidation. Thus, BC can be TEMPO-oxidized without great loss in its structure and properties. (author)

Plumage bacterial assemblages in a breeding wild passerine: relationships with ecological factors and body condition.

Science.gov (United States)

Saag, Pauli; Tilgar, Vallo; Mänd, Raivo; Kilgas, Priit; Mägi, Marko

2011-05-01

Microorganisms have been shown to play an important role in shaping the life histories of animals, and it has recently been suggested that feather-degrading bacteria influence the trade-off between parental effort and self-preening behavior in birds. We studied a wild breeding population of great tits (Parus major) to explore habitat-, seasonal-, and sex-related variation in feather-degrading and free-living bacteria inhabiting the birds' yellow ventral feathers and to investigate associations with body condition. The density and species richness of bacterial assemblages was studied using flow cytometry and ribosomal intergenic spacer analysis. The density of studied bacteria declined between the nest-building period and the first brood. The number of bacterial phylotypes per bird was higher in coniferous habitat, while bacterial densities were higher in deciduous habitat. Free-living bacterial density was positively correlated with female mass; conversely, there was a negative correlation between attached bacterial density and female mass during the period of peak reproductive effort. Bacterial species richness was sex dependent, with more diverse bacterial assemblages present on males than females. Thus, this study revealed that bacterial assemblages on the feathers of breeding birds are affected both by life history and ecological factors and are related to body condition.

Occurrence of hydrocarbon degrading bacteria in soil in Kukawa, Borno State

Directory of Open Access Journals (Sweden)

IA Allamin

2014-05-01

Full Text Available Soil samples were collected from five sites covering petroleum exploration station in Kukawa, Kukawa Local Government Area of Borno State, Nigeria between October, 2012 and February, 2013 at two different depths (0-10cm and 10-20cm to enumerate and identify hydrocarbon degrading bacteria in the soil. Total aerobic heterotrophic bacteria (TAHB were enumerated on Nutrient agar (NA, and Hydrocarbon utilizing bacteria (HUB enumerated on Oil agar (OA. The bacterial isolates were identified using morphological and biochemical tests. It was observed that the microorganisms (TAHB, and HUB were more densely populated at 10cm depth. (TAHB: 5.3×108 - 11.4×108cfu/g, and HUB: 2.4×105 - 5.3×105 cfu/g, than at 20 cm depth (TAHB: 3.0×108 - 5.7×108 cfu/g, and HUB: 2.1×105 - 4.8×105 cfu/g. The HUB was identified as species of Bacillus, Pseudomonas, Klebsiella, Lactobacillus, Micrococcus, Corynebacterium, and Actinomyces. Bacillus, and Pseudomonas species were more constantly isolated than other isolates and they constitute 100% of total bacterial isolates. The potential of hydrocarbon utilizing bacteria isolated to degrade hydrocarbon was studied. Nineteen (19 bacterial species was screened, Bacillus subtilis, Pseudomonas aeruginosa, Bacillus cereus, Klebsiella pneumoniae, Micrococcus leteus,and Lactobacillus casei, utilized and degrade crude oil at considerably high rates after 21 days of incubation. The degradation efficiency was confirmed by GC-MS analysis, which indicated that the bacterial isolates utilized most of the crude oil components particularly straight chain alkanes and cycloalkanes DOI: http://dx.doi.org/10.3126/ije.v3i2.10503 International Journal of the Environment Vol.3(2 2014: 36-47

Bacterial removal of toxic phenols from an industrial effluent

African Journals Online (AJOL)

STORAGESEVER

2008-07-04

Jul 4, 2008 ... Chlorinated phenols, widely used in industries, are of growing concern owing to their high toxicity, .... phenol-degradation ability of bacterial isolate at the high phenol .... ed virtually no decrease in the respiratory response over.

Bacterial and fungal communities in a degraded ombrotrophic peatland undergoing natural and managed re-vegetation.

Science.gov (United States)

Elliott, David R; Caporn, Simon J M; Nwaishi, Felix; Nilsson, R Henrik; Sen, Robin

2015-01-01

The UK hosts 15-19% of global upland ombrotrophic (rain fed) peatlands that are estimated to store 3.2 billion tonnes of carbon and represent a critical upland habitat with regard to biodiversity and ecosystem services provision. Net production is dependent on an imbalance between growth of peat-forming Sphagnum mosses and microbial decomposition by microorganisms that are limited by cold, acidic, and anaerobic conditions. In the Southern Pennines, land-use change, drainage, and over 200 years of anthropogenic N and heavy metal deposition have contributed to severe peatland degradation manifested as a loss of vegetation leaving bare peat susceptible to erosion and deep gullying. A restoration programme designed to regain peat hydrology, stability and functionality has involved re-vegetation through nurse grass, dwarf shrub and Sphagnum re-introduction. Our aim was to characterise bacterial and fungal communities, via high-throughput rRNA gene sequencing, in the surface acrotelm/mesotelm of degraded bare peat, long-term stable vegetated peat, and natural and managed restorations. Compared to long-term vegetated areas the bare peat microbiome had significantly higher levels of oligotrophic marker phyla (Acidobacteria, Verrucomicrobia, TM6) and lower Bacteroidetes and Actinobacteria, together with much higher ligninolytic Basidiomycota. Fewer distinct microbial sequences and significantly fewer cultivable microbes were detected in bare peat compared to other areas. Microbial community structure was linked to restoration activity and correlated with soil edaphic variables (e.g. moisture and heavy metals). Although rapid community changes were evident following restoration activity, restored bare peat did not approach a similar microbial community structure to non-eroded areas even after 25 years, which may be related to the stabilisation of historic deposited heavy metals pollution in long-term stable areas. These primary findings are discussed in relation to bare peat

Bacterial and fungal communities in a degraded ombrotrophic peatland undergoing natural and managed re-vegetation.

Directory of Open Access Journals (Sweden)

David R Elliott

Full Text Available The UK hosts 15-19% of global upland ombrotrophic (rain fed peatlands that are estimated to store 3.2 billion tonnes of carbon and represent a critical upland habitat with regard to biodiversity and ecosystem services provision. Net production is dependent on an imbalance between growth of peat-forming Sphagnum mosses and microbial decomposition by microorganisms that are limited by cold, acidic, and anaerobic conditions. In the Southern Pennines, land-use change, drainage, and over 200 years of anthropogenic N and heavy metal deposition have contributed to severe peatland degradation manifested as a loss of vegetation leaving bare peat susceptible to erosion and deep gullying. A restoration programme designed to regain peat hydrology, stability and functionality has involved re-vegetation through nurse grass, dwarf shrub and Sphagnum re-introduction. Our aim was to characterise bacterial and fungal communities, via high-throughput rRNA gene sequencing, in the surface acrotelm/mesotelm of degraded bare peat, long-term stable vegetated peat, and natural and managed restorations. Compared to long-term vegetated areas the bare peat microbiome had significantly higher levels of oligotrophic marker phyla (Acidobacteria, Verrucomicrobia, TM6 and lower Bacteroidetes and Actinobacteria, together with much higher ligninolytic Basidiomycota. Fewer distinct microbial sequences and significantly fewer cultivable microbes were detected in bare peat compared to other areas. Microbial community structure was linked to restoration activity and correlated with soil edaphic variables (e.g. moisture and heavy metals. Although rapid community changes were evident following restoration activity, restored bare peat did not approach a similar microbial community structure to non-eroded areas even after 25 years, which may be related to the stabilisation of historic deposited heavy metals pollution in long-term stable areas. These primary findings are discussed in

Bacterial and Fungal Communities in a Degraded Ombrotrophic Peatland Undergoing Natural and Managed Re-Vegetation

Science.gov (United States)

Elliott, David R.; Caporn, Simon J. M.; Nwaishi, Felix; Nilsson, R. Henrik; Sen, Robin

2015-01-01

The UK hosts 15–19% of global upland ombrotrophic (rain fed) peatlands that are estimated to store 3.2 billion tonnes of carbon and represent a critical upland habitat with regard to biodiversity and ecosystem services provision. Net production is dependent on an imbalance between growth of peat-forming Sphagnum mosses and microbial decomposition by microorganisms that are limited by cold, acidic, and anaerobic conditions. In the Southern Pennines, land-use change, drainage, and over 200 years of anthropogenic N and heavy metal deposition have contributed to severe peatland degradation manifested as a loss of vegetation leaving bare peat susceptible to erosion and deep gullying. A restoration programme designed to regain peat hydrology, stability and functionality has involved re-vegetation through nurse grass, dwarf shrub and Sphagnum re-introduction. Our aim was to characterise bacterial and fungal communities, via high-throughput rRNA gene sequencing, in the surface acrotelm/mesotelm of degraded bare peat, long-term stable vegetated peat, and natural and managed restorations. Compared to long-term vegetated areas the bare peat microbiome had significantly higher levels of oligotrophic marker phyla (Acidobacteria, Verrucomicrobia, TM6) and lower Bacteroidetes and Actinobacteria, together with much higher ligninolytic Basidiomycota. Fewer distinct microbial sequences and significantly fewer cultivable microbes were detected in bare peat compared to other areas. Microbial community structure was linked to restoration activity and correlated with soil edaphic variables (e.g. moisture and heavy metals). Although rapid community changes were evident following restoration activity, restored bare peat did not approach a similar microbial community structure to non-eroded areas even after 25 years, which may be related to the stabilisation of historic deposited heavy metals pollution in long-term stable areas. These primary findings are discussed in relation to bare

Polycyclic aromatic hydrocarbons (PAHs) biodegradation potential and diversity of microbial consortia enriched from tsunami sediments in Miyagi, Japan

Energy Technology Data Exchange (ETDEWEB)

Bacosa, Hernando Pactao, E-mail: hernando.bacosa@utexas.edu [Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Marine Science Institute, The University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373 (United States); Inoue, Chihiro [Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

2015-02-11

Highlights: • Most bacterial consortia from tsunami sediment degraded PAH mixture and pyrene. • The consortia were dominated by known and unknown PAHs-degrading bacteria. • Dokdonella clone is a potential new species and PAH degrader from tsunami sediment. • PAH-RHDα is better than nidA gene for estimating pyrene-degraders in the consortia. • First report on the PAH degradation and PAH-degrading bacteria from tsunami sediment. - Abstract: The Great East Japan Earthquake caused tsunamis and resulted in widespread damage to human life and infrastructure. The disaster also resulted in contamination of the environment by chemicals such as polycyclic aromatic hydrocarbons (PAHs). This study was conducted to investigate the degradation potential and describe the PAH-degrading microbial communities from tsunami sediments in Miyagi, Japan. PAH-degrading bacteria were cultured by enrichment using PAH mixture or pyrene alone as carbon and energy sources. Among the ten consortia tested for PAH mixture, seven completely degraded fluorene and more than 95% of phenanthrene in 10 days, while only four consortia partially degraded pyrene. Six consortia partially degraded pyrene as a single substrate. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) revealed that each sample was dominated by unique microbial populations, regardless of sampling location. The consortia were dominated by known PAHs degraders including Sphingomonas, Pseudomonas, and Sphingobium; and previously unknown degraders such as Dokdonella and Luteimonas. A potentially novel and PAH-degrading Dokdonella was detected for the first time. PAH-ring hydroxylating dioxygenase (PAH-RHDα) gene was shown to be more effective than nidA in estimating pyrene-degrading bacteria in the enriched consortia. The consortia obtained in this study are potential candidates for remediation of PAHs contaminated soils.

Polycyclic aromatic hydrocarbons (PAHs) biodegradation potential and diversity of microbial consortia enriched from tsunami sediments in Miyagi, Japan

International Nuclear Information System (INIS)

Bacosa, Hernando Pactao; Inoue, Chihiro

2015-01-01

Highlights: • Most bacterial consortia from tsunami sediment degraded PAH mixture and pyrene. • The consortia were dominated by known and unknown PAHs-degrading bacteria. • Dokdonella clone is a potential new species and PAH degrader from tsunami sediment. • PAH-RHDα is better than nidA gene for estimating pyrene-degraders in the consortia. • First report on the PAH degradation and PAH-degrading bacteria from tsunami sediment. - Abstract: The Great East Japan Earthquake caused tsunamis and resulted in widespread damage to human life and infrastructure. The disaster also resulted in contamination of the environment by chemicals such as polycyclic aromatic hydrocarbons (PAHs). This study was conducted to investigate the degradation potential and describe the PAH-degrading microbial communities from tsunami sediments in Miyagi, Japan. PAH-degrading bacteria were cultured by enrichment using PAH mixture or pyrene alone as carbon and energy sources. Among the ten consortia tested for PAH mixture, seven completely degraded fluorene and more than 95% of phenanthrene in 10 days, while only four consortia partially degraded pyrene. Six consortia partially degraded pyrene as a single substrate. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) revealed that each sample was dominated by unique microbial populations, regardless of sampling location. The consortia were dominated by known PAHs degraders including Sphingomonas, Pseudomonas, and Sphingobium; and previously unknown degraders such as Dokdonella and Luteimonas. A potentially novel and PAH-degrading Dokdonella was detected for the first time. PAH-ring hydroxylating dioxygenase (PAH-RHDα) gene was shown to be more effective than nidA in estimating pyrene-degrading bacteria in the enriched consortia. The consortia obtained in this study are potential candidates for remediation of PAHs contaminated soils

Modified nanocrystal cellulose/fluorene-containing sulfonated poly(ether ether ketone ketone) composites for proton exchange membranes

Science.gov (United States)

Wei, Yingcong; Shang, Yabei; Ni, Chuangjiang; Zhang, Hanyu; Li, Xiaobai; Liu, Baijun; Men, Yongfeng; Zhang, Mingyao; Hu, Wei

2017-09-01

Highly sulfonated poly(ether ether ketone ketone)s (SFPEEKKs) with sulfonation degrees of 2.34 (SFPEEKK5) and 2.48 (SFPEEKK10) were synthesized through the direct sulfonation of a fluorene-containing poly(ether ether ketone ketone) under a relatively mild reaction condition. Using the solution blending method, sulfonated nanocrystal cellulose (sNCC)-enhanced SFPEEKK composites (SFPEEKK/sNCC) were successfully prepared for investigation as proton exchange membranes. Transmission electron microscopy showed that sNCC was uniformly distributed in the composite membranes. The properties of the composite membranes, including thermal stability, mechanical properties, water uptake, swelling ratio, oxidative stability and proton conductivity were thoroughly evaluated. Results indicated that the insertion of sNCC could contribute to water management and improve the mechanical performance of the membranes. Notably, the proton conductivity of SFPEEKK5/sNCC-5 was as high as 0.242 S cm-1 at 80 °C. All data proved the potential of SFPEEKK/sNCC composites for proton exchange membranes in medium-temperature fuel cells.

THE EFFECTS OF TEMPERATURE AND pH ON BACTERIAL ...

African Journals Online (AJOL)

PROF EKWUEME

The effect of temperature and pH on bacterial degradation of latex paint under humid condition by .... blade and plastic bags as described by Okpokwasili and. Ituen(1996) and .... provided different ecological niche for bacteria at favourable ...

New method to determine wools and hairs degradation

OpenAIRE

Marsal Amenós, Félix

2013-01-01

A new method is proposed, validated in the industrial practice, to determine possible bacterial and microbial degradation in textile wools and hairs. It is applied to wools of variable fineness between 18 and 34 microns and to alpaca fibers between 20 and 36 microns. It is based on a dynamometer test to determine tribocharge excision the slivers combed. The rheological behavior of degraded fiber slivers is quite different in the spinning process in addition to the major problems that appear i...

Phylogenetic diversity of dominant bacterial communities during bioremediation of crude oil-polluted soil

Directory of Open Access Journals (Sweden)

Eugene Thomas Cloete

2011-08-01

Full Text Available Bioremediation of hydrocarbon pollutants is advantageous owing to the cost-effectiveness of the technology and the ubiquity of hydrocarbon degrading microorganisms in the soil. Soil microbial diversity is affected by hydrocarbon perturbation thus selective enrichment of hydrocarbon utilizers occurs. Hydrocarbons interact with the soil matrix and soil microorganisms determining the fate of the contaminants relative to their chemical nature and microbial degradative capabilities respectively. Bacterial dynamics in crude oil-polluted soil microcosms undergoing bioremediation were investigated over a 42-day period. Four out of the five microcosms containing 4kg of pristine soil each were contaminated with 4% Arabian light crude oil. Three microcosms were amended with either 25g of NPK fertilizer, calcium ammonium nitrate or poultry droppings respectively while the fourth designated oil-contaminated control was unamended. The fifth microcosm had only pristine soil and was set up to ascertain indigenous bacterial community structure pre-contamination. Biostimulated soils were periodically tilled and watered. Hydrocarbon degradation was measured throughout the experimental period by gas chromatography. Gas chromatographic tracing of residual hydrocarbons in biostimulated soils showed marked attenuation of contaminants starting from the second (day 14 till the sixth (day 42 week after contamination whereas no significant reduction in hydrocarbon peaks was seen in the oil contaminated control soil throughout the 6-week experimental period. Molecular fingerprints of bacterial communities involved in aerobic biodegradation of crude oil hydrocarbons in biostimulated soils and controls were generated with DGGE using PCR-amplification of 16S rRNA gene obtained from extracted total soil community DNA. DGGE fingerprints demonstrated that NPK, calcium ammonium nitrate and poultry droppings selected different bacterial populations during the active phase of oil

Prediction by promoter logic in bacterial quorum sensing.

Directory of Open Access Journals (Sweden)

Navneet Rai

2012-01-01

Full Text Available Quorum-sensing systems mediate chemical communication between bacterial cells, coordinating cell-density-dependent processes like biofilm formation and virulence-factor expression. In the proteobacterial LuxI/LuxR quorum sensing paradigm, a signaling molecule generated by an enzyme (LuxI diffuses between cells and allosterically stimulates a transcriptional regulator (LuxR to activate its cognate promoter (pR. By expressing either LuxI or LuxR in positive feedback from pR, these versatile systems can generate smooth (monostable or abrupt (bistable density-dependent responses to suit the ecological context. Here we combine theory and experiment to demonstrate that the promoter logic of pR - its measured activity as a function of LuxI and LuxR levels - contains all the biochemical information required to quantitatively predict the responses of such feedback loops. The interplay of promoter logic with feedback topology underlies the versatility of the LuxI/LuxR paradigm: LuxR and LuxI positive-feedback systems show dramatically different responses, while a dual positive/negative-feedback system displays synchronized oscillations. These results highlight the dual utility of promoter logic: to probe microscopic parameters and predict macroscopic phenotype.

Aerobic degradation of methyl tert-butyl ether in a closed symbiotic system containing a mixed culture of Chlorella ellipsoidea and Methylibium petroleiphilum PM1.

Science.gov (United States)

Zhong, Weihong; Li, Yixiao; Sun, Kedan; Jin, Jing; Li, Xuanzhen; Zhang, Fuming; Chen, Jianmeng

2011-01-30

The contamination of groundwater by methyl tert-butyl ether (MTBE) is one of the most serious environmental problems around the world. MTBE degradation in a closed algal-bacterial symbiotic system, containing a mixed culture of Methylibium petroleiphilum PM1 and Chlorella ellipsoidea, was investigated. The algal-bacterial symbiotic system showed increased MTBE degradation. The MTBE-degradation rate in the mixed culture (8.808 ± 0.007 mg l(-1) d(-1)) was higher than that in the pure bacterial culture (5.664 ± 0.017 mg l(-1) d(-1)). The level of dissolved oxygen was also higher in the mixed culture than that in the pure bacterial culture. However, the improved efficiency of MTBE degradation was not in proportional to the biomass of the alga. The optimal ratio of initial cell population of bacteria to algae was 100:1. An immobilized culture of mixed bacteria and algae also showed higher MTBE degradation rate than the immobilized pure bacterial culture. A mixed culture with algae and PM1 immobilized separately in different gel beads showed higher degradation rate (8.496 ± 0.636 mg l(-1) d(-1)) than that obtained with algae and PM1 immobilized in the same gel beads (5.424 ± 0.010 mg l(-1) d(-1)). Copyright © 2010 Elsevier B.V. All rights reserved.

Degradation and toxicity of phenyltin compounds in soil

International Nuclear Information System (INIS)

Paton, G.I.; Cheewasedtham, W.; Marr, I.L.; Dawson, J.J.C.

2006-01-01

Although the fate of organotins has been widely studied in the marine environment, fewer studies have considered their impact in terrestrial systems. The degradation and toxicity of triphenyltin in autoclaved, autoclaved-reinoculated and non-sterilised soil was studied in a 231 day incubation experiment following a single application. Degradation and toxicity of phenyltin compounds in soil was monitored using both chemical and microbial (lux-based bacterial biosensors) methods. Degradation was significantly slower in the sterile soil when compared to non-sterilised soils. In the non-sterilised treatment, the half-life of triphenyltin was 27 and 33 days at amendments of 10 and 20 mg Sn kg -1 , respectively. As initial triphenyltin degradation occurred, there was a commensurate increase in toxicity, reflecting the fact that metabolites produced may be both more bioavailable and toxic to the target receptor. Over time, the toxicity reduced as degradation proceeded. The toxicity impact on non-target receptors for these compounds may be significant. - Triphenyltin degradative metabolites cause toxic responses to biosensors

Bacterial communities in sediment of a Mediterranean marine protected area.

Science.gov (United States)

Catania, Valentina; Sarà, Gianluca; Settanni, Luca; Quatrini, Paola

2017-04-01

Biodiversity is crucial in preservation of ecosystems, and bacterial communities play an indispensable role for the functioning of marine ecosystems. The Mediterranean marine protected area (MPA) "Capo Gallo-Isola delle Femmine" was instituted to preserve marine biodiversity. The bacterial diversity associated with MPA sediment was compared with that from sediment of an adjacent harbour exposed to intense nautical traffic. The MPA sediment showed higher diversity with respect to the impacted site. A 16S rDNA clone library of the MPA sediment allowed the identification of 7 phyla: Proteobacteria (78%), Firmicutes (11%), Acidobacteria (3%), Actinobacteria (3%), Bacteroidetes (2%), Planctomycetes (2%), and Cyanobacteria (1%). Analysis of the hydrocarbon (HC)-degrading bacteria was performed using enrichment cultures. Most of the MPA sediment isolates were affiliated with Gram-positive G+C rich bacteria, whereas the majority of taxa in the harbour sediment clustered with Alpha- and Gammaproteobacteria; no Gram-positive HC degraders were isolated from the harbour sediment. Our results show that protection probably has an influence on bacterial diversity, and suggest the importance of monitoring the effects of protection at microbial level as well. This study creates a baseline of data that can be used to assess changes over time in bacterial communities associated with a Mediterranean MPA.

Aerobic Degradation of Drill Muds by Axenic and Mixed Bacterial ...

African Journals Online (AJOL)

Prof. Ogunji

significant difference in the degradation of the drilling muds by the isolates (p > 0.05). ... the potentials of some indigenous bacteria to biodegrade drilling muds used in ... transported to the laboratory aseptically for evaluation, in labeled plastic.

Assessment of Bacterial Degradation of Aromatic Hydrocarbons in the Environment by Analysis of Stable Carbon Isotope Fractionation

Energy Technology Data Exchange (ETDEWEB)

Meckenstock, Rainer U. [Eberhard-Karls University of Tuebingen, Center for Applied Geoscience (Germany)], E-mail: rainer.meckenstock@uni-tuebingen.de; Morasch, Barbara [University of Konstanz, Faculty of Biology (Germany); Kaestner, Matthias; Vieth, Andrea; Richnow, Hans Hermann [Center for Environmental Research, Department of Remediation Research (Germany)

2002-05-15

{sup 13}C/{sup 12}C stable carbon isotope fractionation was used to assess biodegradation in contaminated aquifers with toluene as a model compound. Different strains of anaerobic bacteria (Thauera aromatica, Geobacter metallireducens, and the sulfate-reducing strain TRM1) showed consistent {sup 13}C/{sup 12}C carbon isotope fractionation with fractionation factors between {alpha}C = 1.0017 and 1.0018. In contrast, three cultures of aerobic organisms, using different mono- and dioxygenase enzyme systems to initiate toluene degradation, showed variable isotope fractionation factors of {alpha}C = 1.0027 (Pseudomonasputida strain mt-2), {alpha}C = 1.0011 (Ralstonia picketii), and{alpha}C = 1.0004 (Pseudomonas putida strain F1). The great variability of isotope fractionation between different aerobic bacterial strains suggests that interpretation of isotope data in oxic habitats can only be qualitative. A soil column was run as a model system for contaminated aquifers with toluene as the carbon source and sulfate as the electron acceptor and samples were taken at different ports along the column. Microbial toluene degradation was calculated based on the {sup 13}C/{sup 12}C isotope fractionation factors of the batch culture experiments together with the observed {sup 13}C/{sup 12}C isotope shifts of the residual toluene fractions. The calculated percentage of biodegradation, B, correlated well with the decreasing toluene concentrations at the sampling ports and indicated the increasing extent of biodegradation along the column. The theoretical toluene concentrations as calculated based on the isotope values matched the measured concentrations at the different sampling ports indicating that the Rayleigh equation can be used to calculate biodegradation in quasi closed systems based on measured isotope shifts. A similar attempt was performed to assess toluene degradation in a contaminated, anoxic aquifer. A transect of groundwater wells was monitored along the main

Evaluation of microbially-influenced degradation of massive concrete structures

International Nuclear Information System (INIS)

Hamilton, M.A.; Rogers, R.D.; Zolynski, M.; Veeh, R.

1996-01-01

Many low level waste disposal vaults, both above and below ground, are constructed of concrete. One potential contributing agent to the destruction of concrete structures is microbially-influenced degradation (MID). Three groups of bacteria are known to create conditions that are conducive to destroying concrete integrity. They are sulfur oxidizing bacteria, nitrifying bacteria, and heterotrophic bacteria. Research is being conducted at the Idaho National Engineering Laboratory to assess the extent of naturally occurring microbially influenced degradation (MID) and its contribution to the deterioration of massive concrete structures. The preliminary steps to understanding the extent of MID, require assessing the microbial communities present on degrading concrete surfaces. Ultimately such information can be used to develop guidelines for preventive or corrective treatments for MID and aid in formulation of new materials to resist corrosion. An environmental study was conducted to determine the presence and activity of potential MID bacteria on degrading concrete surfaces of massive concrete structures. Scanning electron microscopy detected bacteria on the surfaces of concrete structures such as bridges and dams, where corrosion was evident. Enumeration of sulfur oxidizing thiobacilli and nitrogen oxidizing Nitrosomonas sp. and Nitrobacter sp. from surface samples was conducted. Bacterial community composition varied between sampling locations, and generally the presence of either sulfur oxidizers or nitrifiers dominated, although instances of both types of bacteria occurring together were encountered. No clear correlation between bacterial numbers and degree of degradation was exhibited

Comparative genomics and transcriptomics depict ericoid mycorrhizal fungi as versatile saprotrophs and plant mutualists.

Science.gov (United States)

Martino, Elena; Morin, Emmanuelle; Grelet, Gwen-Aëlle; Kuo, Alan; Kohler, Annegret; Daghino, Stefania; Barry, Kerrie W; Cichocki, Nicolas; Clum, Alicia; Dockter, Rhyan B; Hainaut, Matthieu; Kuo, Rita C; LaButti, Kurt; Lindahl, Björn D; Lindquist, Erika A; Lipzen, Anna; Khouja, Hassine-Radhouane; Magnuson, Jon; Murat, Claude; Ohm, Robin A; Singer, Steven W; Spatafora, Joseph W; Wang, Mei; Veneault-Fourrey, Claire; Henrissat, Bernard; Grigoriev, Igor V; Martin, Francis M; Perotto, Silvia

2018-02-01

Some soil fungi in the Leotiomycetes form ericoid mycorrhizal (ERM) symbioses with Ericaceae. In the harsh habitats in which they occur, ERM plant survival relies on nutrient mobilization from soil organic matter (SOM) by their fungal partners. The characterization of the fungal genetic machinery underpinning both the symbiotic lifestyle and SOM degradation is needed to understand ERM symbiosis functioning and evolution, and its impact on soil carbon (C) turnover. We sequenced the genomes of the ERM fungi Meliniomyces bicolor, M. variabilis, Oidiodendron maius and Rhizoscyphus ericae, and compared their gene repertoires with those of fungi with different lifestyles (ecto- and orchid mycorrhiza, endophytes, saprotrophs, pathogens). We also identified fungal transcripts induced in symbiosis. The ERM fungal gene contents for polysaccharide-degrading enzymes, lipases, proteases and enzymes involved in secondary metabolism are closer to those of saprotrophs and pathogens than to those of ectomycorrhizal symbionts. The fungal genes most highly upregulated in symbiosis are those coding for fungal and plant cell wall-degrading enzymes (CWDEs), lipases, proteases, transporters and mycorrhiza-induced small secreted proteins (MiSSPs). The ERM fungal gene repertoire reveals a capacity for a dual saprotrophic and biotrophic lifestyle. This may reflect an incomplete transition from saprotrophy to the mycorrhizal habit, or a versatile life strategy similar to fungal endophytes. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Exploring the potential of fungal-bacterial consortium for low-cost biodegradation and detoxification of textile effluent

Directory of Open Access Journals (Sweden)

Lade Harshad

2016-12-01

Full Text Available In the present study, the enrichment and isolation of textile effluent decolorizing bacteria were carried out in wheat bran (WB medium. The isolated bacterium Providencia rettgeri strain HSL1 was then tested for decolorization of textile effluent in consortium with a dyestuff degrading fungus Aspergillus ochraceus NCIM 1146. Decolorization study suggests that A. ochraceus NCIM 1146 and P. rettgeri strain HSL1 alone re moves only 6 and 32% of textile effluent American Dye Manufacturing Institute respectively in 30 h at 30 ±0.2°C of microaerophilic incubation, while the fungal-bacterial consortium does 92% ADMI removal within the same time period. The fungal-bacterial consortium exhibited enhanced decolorization rate due to the induction in activities of catalytic enzymes laccase (196%, lignin peroxidase (77%, azoreductase (80% and NADH-DCIP reductase (84%. The HPLC analysis confirmed the biodegradation of textile effluent into various metabolites. Detoxification studies of textile effluent before and after treatment with fungal-bacterial consortium revealed reduced toxicity of degradation metabolites. The efficient degradation and detoxification by fungal-bacterial consortium pre-grown in agricultural based medium thus suggest a promising approach in designing low-cost treatment technologies for textile effluent.

Effective pesticide nano formulations and their bacterial degradation

Science.gov (United States)

Ramadass, M.; Thiagarajan, P.

2017-11-01

The use of chemical pesticides for agricultural pest control and the consequent damage to the ecosystem at air, water and soil levels has become a factor of common knowledge. This alarming trend has led to research and development in the area of nanoformulations to achieve the end use of pest control with very low concentrations of pesticides. Such formulations are being proven to be as effective as traditional formulations due to their inherent ability to achieve controlled delivery of their respective active ingredients. The end result is a successful pest control with minimum environmental damage. Despite this, certain organic groups, that form the essential structural constituents of these pesticides, are not readily degraded due to their complex nature. They continue to persist, accumulate and biomagnify in the environment leading to short and long term hazards. In this context, it has been noted that certain common genera of bacteria such as Bacillus, Pseudomonas, Flavobacterium, Sphingomonas, Brevibacterium, Burkholderia, etc possess the inherent ability to utilise specific chemical groups in the pesticides as their sole source of either carbon and / or nitrogen and consequently achieve their conversion into non-toxic end products. A potential bioremediation process is thus slowly gaining popularity and being implemented on a pilot scale. However, large scale successful pesticide microbial remediation will involve experimentation with several combinations of a variety of nano pesticide formulations with different genera of bacteria under optimised conditions. Such studies will throw light on the precise genus and species of bacteria that may degrade the required groups of pesticides, for environmental damage control in the long run.

Isolation, Screening and Development of Local Bacterial Consortia With Azo Dyes Decolourising Capability

Directory of Open Access Journals (Sweden)

Khadijah, O.

2009-01-01

Full Text Available A total of 1540 bacterial isolates were isolated and screened for their ability to degrade selected azo dyes. Of these, nine isolates were chosen for further studies based on their ability to degrade a wide spectrum of dyes efficiently and rapidly. Several microbial consortia were developed and tested for their effectiveness. Overall the consortia were able to degrade 70 - 100% colour within 72 hours compared to 60 – 97% colour removed by individual isolates. A microbial consortium labelled C15 showed good growth in agitation culture but the colour removal was best in static culture with 80 - 100% colour removed in less than 72 hours. Based on the 16S rRNA sequencing, two of the bacterial isolates in C15 belong to the Chryseobacterium genus while the other one belongs to Flavobacterium genus.

Characterization of microbial consortia in a terephthalate-degrading anaerobic granular sludge system.

Science.gov (United States)

Wu, J H; Liu, W T; Tseng, I C; Cheng, S S

2001-02-01

The microbial composition and spatial distribution in a terephthalate-degrading anaerobic granular sludge system were characterized using molecular techniques. 16S rDNA clone library and sequence analysis revealed that 78.5% of 106 bacterial clones belonged to the delta subclass of the class Proteobacteria; the remaining clones were assigned to the green non-sulfur bacteria (7.5%), Synergistes (0.9%) and unidentified divisions (13.1%). Most of the bacterial clones in the delta-Proteobacteria formed a novel group containing no known bacterial isolates. For the domain Archaea, 81.7% and 18.3% of 72 archaeal clones were affiliated with Methanosaeta and Methanospirillum, respectively. Spatial localization of microbial populations inside granules was determined by transmission electron microscopy and fluorescent in situ hybridization with oligonucleotide probes targeting the novel delta-proteobacterial group, the acetoclastic Methanosaeta, and the hydrogenotrophic Methanospirillum and members of Methanobacteriaceae. The novel group included at least two different populations with identical rod-shape morphology, which made up more than 87% of the total bacterial cells, and were closely associated with methanogenic populations to form a nonlayered granular structure. This novel group was presumed to be the primary bacterial population involved in the terephthalate degradation in the methanogenic granular consortium.

Enhancement of aerobic biodegradability potential of municipal waste activated sludge by ultrasonic aided bacterial disintegration.

Science.gov (United States)

Kavitha, S; Jessin Brindha, G M; Sally Gloriana, A; Rajashankar, K; Yeom, Ick Tae; Rajesh Banu, J

2016-01-01

An investigation was performed to study the influence of ultrasonic aided bacterial disintegration on the aerobic degradability of sludge. In first phase of the study, effective floc disruption was achieved at an ultrasonic specific energy input of 2.45kJ/kg TS with 44.5mg/L of Extracellular Polymeric Substance (EPS) release including 0.035U/mL and 0.025U/mL protease and amylase activity respectively. In second phase, experimental outcomes revealed bacterial disintegration of floc disrupted-sludge showing a maximum solubilization of about 23% and was observed to be superior to bacterially disintegrated (11%) and control (6%), respectively. The result of aerobic biodegradability of ultrasonic aided bacterially pretreated sludge showed volatile solids (VS) degradation of about 40.2%. The kinetic study of aerobic biodegradability through non linear regression modelling reveals that floc disrupted sludge showed better biodegradability with decay constant of about 0.19d(-1) relatively higher than the control (0.14d(-1)) and bacterially disintegrated (0.17d(-1)) sludges. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization of Trapped Lignin-Degrading Microbes in Tropical Forest Soil

Energy Technology Data Exchange (ETDEWEB)

DeAngelis, Kristen; Allgaier, Martin; Chavarria, Yaucin; Fortney, Julian; Hugenholtz, Phillip; Simmons, Blake; Sublette, Kerry; Silver, Whendee; Hazen, Terry

2011-07-14

Lignin is often the most difficult portion of plant biomass to degrade, with fungi generally thought to dominate during late stage decomposition. Lignin in feedstock plant material represents a barrier to more efficient plant biomass conversion and can also hinder enzymatic access to cellulose, which is critical for biofuels production. Tropical rain forest soils in Puerto Rico are characterized by frequent anoxic conditions and fluctuating redox, suggesting the presence of lignin-degrading organisms and mechanisms that are different from known fungal decomposers and oxygen-dependent enzyme activities. We explored microbial lignin-degraders by burying bio-traps containing lignin-amended and unamended biosep beads in the soil for 1, 4, 13 and 30 weeks. At each time point, phenol oxidase and peroxidase enzyme activity was found to be elevated in the lignin-amended versus the unamended beads, while cellulolytic enzyme activities were significantly depressed in lignin-amended beads. Quantitative PCR of bacterial communities showed more bacterial colonization in the lignin-amended compared to the unamended beads after one and four weeks, suggesting that the lignin supported increased bacterial abundance. The microbial community was analyzed by small subunit 16S ribosomal RNA genes using microarray (PhyloChip) and by high-throughput amplicon pyrosequencing based on universal primers targeting bacterial, archaeal, and eukaryotic communities. Community trends were significantly affected by time and the presence of lignin on the beads. Lignin-amended beads have higher relative abundances of representatives from the phyla Actinobacteria, Firmicutes, Acidobacteria and Proteobacteria compared to unamended beads. This study suggests that in low and fluctuating redox soils, bacteria could play a role in anaerobic lignin decomposition.

Characterization of trapped lignin-degrading microbes in tropical forest soil

Energy Technology Data Exchange (ETDEWEB)

DeAngelis, K.M.; Allgaier, M.; Chavarria, Y.; Fortney, J.L.; Hugenholz, P.; Simmons, B.; Sublette, K.; Silver, W.L.; Hazen, T.C.

2011-03-01

Lignin is often the most difficult portion of plant biomass to degrade, with fungi generally thought to dominate during late stage decomposition. Lignin in feedstock plant material represents a barrier to more efficient plant biomass conversion and can also hinder enzymatic access to cellulose, which is critical for biofuels production. Tropical rain forest soils in Puerto Rico are characterized by frequent anoxic conditions and fluctuating redox, suggesting the presence of lignin-degrading organisms and mechanisms that are different from known fungal decomposers and oxygen-dependent enzyme activities. We explored microbial lignin-degraders by burying bio-traps containing lignin-amended and unamended biosep beads in the soil for 1, 4, 13 and 30 weeks. At each time point, phenol oxidase and peroxidase enzyme activity was found to be elevated in the lignin-amended versus the unamended beads, while cellulolytic enzyme activities were significantly depressed in lignin-amended beads. Quantitative PCR of bacterial communities showed more bacterial colonization in the lignin-amended compared to the unamended beads after one and four weeks, suggesting that the lignin supported increased bacterial abundance. The microbial community was analyzed by small subunit 16S ribosomal RNA genes using microarray (PhyloChip) and by high-throughput amplicon pyrosequencing based on universal primers targeting bacterial, archaeal, and eukaryotic communities. Community trends were significantly affected by time and the presence of lignin on the beads. Lignin-amended beads have higher relative abundances of representatives from the phyla Actinobacteria, Firmicutes, Acidobacteria and Proteobacteria compared to unamended beads. This study suggests that in low and fluctuating redox soils, bacteria could play a role in anaerobic lignin decomposition.

Fungal hyphae stimulate bacterial degradation of 2,6-dichlorobenzamide (BAM)

DEFF Research Database (Denmark)

Knudsen, Berith Elkær; Ellegaard-Jensen, Lea; Albers, Christian Nyrop

2013-01-01

Abstract Introduction of specific degrading microorganisms into polluted soil or aquifers is a promising remediation technology provided that the organisms survive and spread in the environment. We suggest that consortia, rather than single strains, may be better suited to overcome these challenges...

Biodegradation of the anionic surfactant sodium dodecyl sulfate by local bacterial isolate

International Nuclear Information System (INIS)

Ibrahim, H.M.M.; NoorEl-Din, M.R.

2011-01-01

Anionic surfactants, e.g., sodium dodecyl sulfate (SDS), as a main components in the detergent and cosmetic industries, contribute significantly to the pollution profile of sewage and wastewaters of all kinds. The purpose of this study was to isolate local SDS degrading bacteria. Screening was carried out by the conventional enrichment culture technique. One bacterial isolate was obtained; this isolate was primarily defined as gram-negative rods . It was capable of degrading 100% of 1000 and 2000 mg/l of SDS after 6 days of incubation. The isolate exhibited maximum growth at SDS concentration 4000 mg/I, but it was significantly decreased at higher concentration (16000 mg/I).All the carbon sources being tested repressed the degradation ability. Sodium nitrate at concentration of 2.0 g/I was the best nitrogen source for growth and SDS biodegradation, it enhanced the degradation of 3000 mg/I SDS by 95%,i.e., by 32% upon the control (broth medium containing NH 4 Cl). SDS degradation by the bacterium was optimum at initial ph 8.5, incubation temperature 35 degree C, and inoculum size 2% (v/v). Under the optimized conditions, almost 98% of initial SDS concentration (4000 mg/l) was degraded after 120 h of incubation. Gamma irradiation did not improve the biodegradation ability of this bacterial isolate.

Bioremediation and reclamation of soil contaminated with petroleum oil hydrocarbons by exogenously seeded bacterial consortium: a pilot-scale study.

Science.gov (United States)

Mukherjee, Ashis K; Bordoloi, Naba K

2011-03-01

Spillage of petroleum hydrocarbons causes significant environmental pollution. Bioremediation is an effective process to remediate petroleum oil contaminant from the ecosystem. The aim of the present study was to reclaim a petroleum oil-contaminated soil which was unsuitable for the cultivation of crop plants by using petroleum oil hydrocarbon-degrading microbial consortium. Bacterial consortium consisting of Bacillus subtilis DM-04 and Pseudomonas aeruginosa M and NM strains were seeded to 20% (v/w) petroleum oil-contaminated soil, and bioremediation experiment was carried out for 180 days under laboratory condition. The kinetics of hydrocarbon degradation was analyzed using biochemical and gas chromatographic (GC) techniques. The ecotoxicity of the elutriates obtained from petroleum oil-contaminated soil before and post-treatment with microbial consortium was tested on germination and growth of Bengal gram (Cicer aretinum) and green gram (Phaseolus mungo) seeds. Bacterial consortium showed a significant reduction in total petroleum hydrocarbon level in contaminated soil (76% degradation) as compared to the control soil (3.6% degradation) 180 days post-inoculation. The GC analysis confirmed that bacterial consortium was more effective in degrading the alkane fraction compared to aromatic fraction of crude petroleum oil hydrocarbons in soil. The nitrogen, sulfur, and oxygen compounds fraction was least degraded. The reclaimed soil supported the germination and growth of crop plants (C. aretinum and P. mungo). In contrast, seeds could not be germinated in petroleum oil-contaminated soil. The present study reinforces the application of bacterial consortium rather than individual bacterium for the effective bioremediation and reclamation of soil contaminated with petroleum oil.

Biodegradation of carcinogenic textile azo dyes using bacterial isolates of mangrove sediment

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Guru Prasad Srinivasan

2014-02-01

Full Text Available Objective: To evaluate the biodegrading property against carcinogenic azo dyes using bacterial isolates of mangrove sediment. Methods: The bacterial isolates were subjected to submerged fermentation and their growth kinetics were studied. The potential strain was characterized using 16S rDNA sequencing. Results: In the present study, dye degrading bacterial colonies were isolated from the mangrove sediment samples of Parangipettai estuarine area, Tamil Nadu. Of the 30 morphologically different strains isolated, 5 showed antagonistic property. The growth kinetics of the two strains, P1 and G1, which showed potent activity were calculated. One particular isolate (P1 showing promising dye degrading potential in the submerged fermentation was further characterized. The strain was identified as Paenibacillus sp. by 16S rDNA sequencing. Conclusions: This study reveals the less explored microflora of mangrove sediments. The novel strain may further be analyzed and used in the treatment of effluent from dye industry so as to reduce the impact of carcinogenic contaminants.

Salix purpurea Stimulates the Expression of Specific Bacterial Xenobiotic Degradation Genes in a Soil Contaminated with Hydrocarbons.

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Antoine P Pagé

Full Text Available The objectives of this study were to uncover Salix purpurea-microbe xenobiotic degradation systems that could be harnessed in rhizoremediation, and to identify microorganisms that are likely involved in these partnerships. To do so, we tested S. purpurea's ability to stimulate the expression of 10 marker microbial oxygenase genes in a soil contaminated with hydrocarbons. In what appeared to be a detoxification rhizosphere effect, transcripts encoding for alkane 1-monooxygenases, cytochrome P450 monooxygenases, laccase/polyphenol oxidases, and biphenyl 2,3-dioxygenase small subunits were significantly more abundant in the vicinity of the plant's roots than in bulk soil. This gene expression induction is consistent with willows' known rhizoremediation capabilities, and suggests the existence of S. purpurea-microbe systems that target many organic contaminants of interest (i.e. C4-C16 alkanes, fluoranthene, anthracene, benzo(apyrene, biphenyl, polychlorinated biphenyls. An enhanced expression of the 4 genes was also observed within the bacterial orders Actinomycetales, Rhodospirillales, Burkholderiales, Alteromonadales, Solirubrobacterales, Caulobacterales, and Rhizobiales, which suggest that members of these taxa are active participants in the exposed partnerships. Although the expression of the other 6 marker genes did not appear to be stimulated by the plant at the community level, signs of additional systems that rest on their expression by members of the orders Solirubrobacterales, Sphingomonadales, Actinomycetales, and Sphingobacteriales were observed. Our study presents the first transcriptomics-based identification of microbes whose xenobiotic degradation activity in soil appears stimulated by a plant. It paints a portrait that contrasts with the current views on these consortia's composition, and opens the door for the development of laboratory test models geared towards the identification of root exudate characteristics that limit the

Asymmetric transfer hydrogenation of ketones in aqueous solution catalyzed by Rhodium(III) complexes with C2-symmetric fluorene-ligands containing chiral (1R,2R)-cyclohexane-1,2-diamine

International Nuclear Information System (INIS)

Montalvo-Gonzalez, Ruben; Chavez, Daniel; Aguirre, Gerardo; Parra-Hake, Miguel; Somanathan, Ratnasamy

2010-01-01

Two C 2 -symmetric bis(sulfonamide) ligands containing fluorene-chiral (1R, 2R)-cyclohexane-1,2-diamine were complexed to Rh III (Cp * ) and used as catalyst to reduce aromatic ketones. The corresponding chiral secondary alcohols were obtained in 87-100% ee and 85-99% yield, under asymmetric transfer hydrogenation (ATH) conditions using aqueous sodium formate as the hydride source. With acetophenone, 94% ee and 86-97% yield was achieved with substrate/catalyst (S/C) ratio of 10,000. (author)

Stable Isotope Fractionation Caused by Glycyl Radical Enzymes during Bacterial Degradation of Aromatic Compounds

Science.gov (United States)

Morasch, Barbara; Richnow, Hans H.; Vieth, Andrea; Schink, Bernhard; Meckenstock, Rainer U.

2004-01-01

Stable isotope fractionation was studied during the degradation of m-xylene, o-xylene, m-cresol, and p-cresol with two pure cultures of sulfate-reducing bacteria. Degradation of all four compounds is initiated by a fumarate addition reaction by a glycyl radical enzyme, analogous to the well-studied benzylsuccinate synthase reaction in toluene degradation. The extent of stable carbon isotope fractionation caused by these radical-type reactions was between enrichment factors (ɛ) of −1.5 and −3.9‰, which is in the same order of magnitude as data provided before for anaerobic toluene degradation. Based on our results, an analysis of isotope fractionation should be applicable for the evaluation of in situ bioremediation of all contaminants degraded by glycyl radical enzyme mechanisms that are smaller than 14 carbon atoms. In order to compare carbon isotope fractionations upon the degradation of various substrates whose numbers of carbon atoms differ, intrinsic ɛ (ɛintrinsic) were calculated. A comparison of ɛintrinsic at the single carbon atoms of the molecule where the benzylsuccinate synthase reaction took place with compound-specific ɛ elucidated that both varied on average to the same extent. Despite variations during the degradation of different substrates, the range of ɛ found for glycyl radical reactions was reasonably narrow to propose that rough estimates of biodegradation in situ might be given by using an average ɛ if no fractionation factor is available for single compounds. PMID:15128554

Anaerobic biodegradation of nonylphenol in river sediment under nitrate- or sulfate-reducing conditions and associated bacterial community

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhao; Yang, Yuyin; Dai, Yu; Xie, Shuguang, E-mail: xiesg@pku.edu.cn

2015-04-09

Highlights: • NP biodegradation can occur under both nitrate- and sulfate-reducing conditions. • Anaerobic condition affects sediment bacterial diversity during NP biodegradation. • NP-degrading bacterial community structure varies under different anaerobic conditions. - Abstract: Nonylphenol (NP) is a commonly detected pollutant in aquatic ecosystem and can be harmful to aquatic organisms. Anaerobic degradation is of great importance for the clean-up of NP in sediment. However, information on anaerobic NP biodegradation in the environment is still very limited. The present study investigated the shift in bacterial community structure associated with NP degradation in river sediment microcosms under nitrate- or sulfate-reducing conditions. Nearly 80% of NP (100 mg kg{sup −1}) could be removed under these two anaerobic conditions after 90 or 110 days’ incubation. Illumina MiSeq sequencing analysis indicated that Proteobacteria, Firmicutes, Bacteroidetes and Chloroflexi became the dominant phylum groups with NP biodegradation. The proportion of Gammaproteobacteria, Deltaproteobacteria and Choloroflexi showed a marked increase in nitrate-reducing microcosm, while Gammaproteobacteria and Firmicutes in sulfate-reducing microcosm. Moreover, sediment bacterial diversity changed with NP biodegradation, which was dependent on type of electron acceptor.

Identification of Anaerobic Aniline-Degrading Bacteria at a Contaminated Industrial Site.

Science.gov (United States)

Sun, Weimin; Li, Yun; McGuinness, Lora R; Luo, Shuai; Huang, Weilin; Kerkhof, Lee J; Mack, E Erin; Häggblom, Max M; Fennell, Donna E

2015-09-15

Anaerobic aniline biodegradation was investigated under different electron-accepting conditions using contaminated canal and groundwater aquifer sediments from an industrial site. Aniline loss was observed in nitrate- and sulfate-amended microcosms and in microcosms established to promote methanogenic conditions. Lag times of 37 days (sulfate amended) to more than 100 days (methanogenic) were observed prior to activity. Time-series DNA-stable isotope probing (SIP) was used to identify bacteria that incorporated (13)C-labeled aniline in the microcosms established to promote methanogenic conditions. In microcosms from heavily contaminated aquifer sediments, a phylotype with 92.7% sequence similarity to Ignavibacterium album was identified as a dominant aniline degrader as indicated by incorporation of (13)C-aniline into its DNA. In microcosms from contaminated canal sediments, a bacterial phylotype within the family Anaerolineaceae, but without a match to any known genus, demonstrated the assimilation of (13)C-aniline. Acidovorax spp. were also identified as putative aniline degraders in both of these two treatments, indicating that these species were present and active in both the canal and aquifer sediments. There were multiple bacterial phylotypes associated with anaerobic degradation of aniline at this complex industrial site, which suggests that anaerobic transformation of aniline is an important process at the site. Furthermore, the aniline degrading phylotypes identified in the current study are not related to any known aniline-degrading bacteria. The identification of novel putative aniline degraders expands current knowledge regarding the potential fate of aniline under anaerobic conditions.

Gas generation from transuranic waste degradation: an interim assessment

International Nuclear Information System (INIS)

Molecke, M.A.

1979-10-01

A review of all available, applicable data pertaining to gas generation from the degradation of transuranic waste matrix material and packaging is presented. Waste forms are representative of existing defense-related TRU wastes and include cellulosics, plastics, rubbers, concrete, process sludges, and mild steel. Degradation mechanisms studied were radiolysis, thermal, bacterial, and chemical corrosion. Gas generation rates are presented in terms of moles of gas produced per year per drum, and in G(gas) values for radiolytic degradation. Comparison of generation rates is made, as is a discussion of potential short- and long-term concerns. Techniques for reducing gas generation rates are discussed. 6 figures, 10 tables

Development of an Efficient Bacterial Consortium for the Potential Remediation of Hydrocarbons from Contaminated Sites.

Science.gov (United States)

Patowary, Kaustuvmani; Patowary, Rupshikha; Kalita, Mohan C; Deka, Suresh

2016-01-01

The intrinsic biodegradability of hydrocarbons and the distribution of proficient degrading microorganisms in the environment are very crucial for the implementation of bioremediation practices. Among others, one of the most favorable methods that can enhance the effectiveness of bioremediation of hydrocarbon-contaminated environment is the application of biosurfactant producing microbes. In the present study, the biodegradation capacities of native bacterial consortia toward total petroleum hydrocarbons (TPH) with special emphasis to poly aromatic hydrocarbons were determined. The purpose of the study was to isolate TPH degrading bacterial strains from various petroleum contaminated soil of Assam, India and develop a robust bacterial consortium for bioremediation of crude oil of this native land. From a total of 23 bacterial isolates obtained from three different hydrocarbons contaminated samples five isolates, namely KS2, PG1, PG5, R1, and R2 were selected as efficient crude oil degraders with respect to their growth on crude oil enriched samples. Isolates KS2, PG1, and R2 are biosurfactant producers and PG5, R1 are non-producers. Fourteen different consortia were designed involving both biosurfactant producing and non-producing isolates. Consortium 10, which comprises two Bacillus strains namely, Bacillus pumilus KS2 and B. cereus R2 (identified by 16s rRNA sequencing) has shown the best result in the desired degradation of crude oil. The consortium showed degradation up to 84.15% of TPH after 5 weeks of incubation, as revealed from gravimetric analysis. FTIR (Fourier transform infrared) and GCMS (Gas chromatography-mass spectrometer) analyses were correlated with gravimetric data which reveals that the consortium has removed a wide range of petroleum hydrocarbons in comparison with abiotic control including different aliphatic and aromatic hydrocarbons.

Development of an efficient bacterial consortium for the potential remediation of hydrocarbons from contaminated sites

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Kaustuvmani Patowary

2016-07-01

Full Text Available The intrinsic biodegradability of hydrocarbons and the distribution of proficient degrading microorganisms in the environment are very crucial for the implementation of bioremediation practices. Among others, one of the most favorable methods that can enhance the effectiveness of bioremediation of hydrocarbon-contaminated environment is the application of biosurfactant producing microbes. In the present study, the biodegradation capacities of native bacterial consortia towards total petroleum hydrocarbons (TPH with special emphasis to poly aromatic hydrocarbons (PAHs were determined. The purpose of the study was to isolate TPH degrading bacterial strains from various petroleum contaminated soil of Assam, India and develop a robust bacterial consortium for bioremediation of crude oil of this native land. From a total of 23 bacterial isolates obtained from three different hydrocarbons contaminated samples 5 isolates, namely KS2, PG1, PG5, R1 and R2 were selected as efficient crude oil degraders with respect to their growth on crude oil enriched samples. Isolates KS2, PG1 and R2 are biosurfactant producers and PG5, R1 are non-producers. Fourteen different consortia were designed involving both biosurfactant producing and non-producing isolates. Consortium 10, which comprises two Bacillus strains namely, Bacillus pumilus KS2 and Bacillus cereus R2 (identified by 16s rRNA sequencing has shown the best result in the desired degradation of crude oil. The consortium showed degradation up to 84.15% of total petroleum hydrocarbon (TPH after five weeks of incubation, as revealed from gravimetric analysis. FTIR (Fourier transform infrared and GCMS (Gas chromatography-mass spectrometer analyses were correlated with gravimetric data which reveals that the consortium has removed a wide range of petroleum hydrocarbons in comparison with abiotic control including different aliphatic and aromatic hydrocarbons.

The Versatile Link Demo Board (VLDB)

International Nuclear Information System (INIS)

Lesma, R. Martín; Alessio, F.; Barbosa, J.; Baron, S.; Caplan, C.; Leitao, P.; Porret, D.; Wyllie, K.; Pecoraro, C.

2017-01-01

The Versatile Link Demonstrator Board (VLDB) is the evaluation kit for the radiation-hard Optical Link ecosystem, which provides a 4.8 Gbps data transfer link for communication between front-end (FE) and back-end (BE) of the High Energy Physics experiments. It gathers the Versatile link main radiation-hard custom Application-Specific Integrated Circuits (ASICs) and modules: GBTx, GBT-SCA and VTRx/VTTx plus the FeastMP, a radiation-hard in-house designed DC-DC converter. This board is the first design allowing system-level tests of the Link with a complete interconnection of the constitutive components, allowing data acquisition, control and monitoring of FE devices with the GBT-SCA pair.

Isolation and application of hydrocarbon degradation of indigenous microbial from oil contaminated soil

International Nuclear Information System (INIS)

Dadang Sudrajat; Nana Mulyana; Tri Retno DL

2015-01-01

The aims of this research are to obtain indigenous potential microbes from bacterial and fungal groups which have capable of degrading hydrocarbon from crude oil contaminated soil. The research carried out were isolation, selection, and identification potential microbial isolates capable of degrading hydrocarbon from oil contaminated soil located at Cepu East Java. The isolates were tested for their growth and ability to degrades crude oil. Each isolate was inoculated unto minimum mineral salt medium (MSM) contained 1% crude oil. Viability and stability test of selected isolates were carried out on irradiated compost carrier materials contained 5% crude oil. The fours series microbial s consortium consists of microbial consortium I, II, III, and IV were tested for the in vitro biodegradability of hydrocarbon. The results shows there sixty two (62) isolates are obtained, among them 42 bacteria and 20 molds. From 42 bacterial isolates, only 8 strains were potent hydrocarbon degraders. Three of these isolates are identified Bacillus cereus (BMC2), Bacillus sp (BMC4), and Pseudomonas sp (BMC6). Whereas from 20 fungal isolates, only 4 strains were potent hydrocarbon degraders. Two of these isolates are identified Aspergillus fumigatus (FMC2) and Aspergillus niger (FMC6). All isolates show good growth in mineral salt medium contained crude oil with decrease in pH. The ability of decrease of TPH content by the bacterial and fungal isolates were 54, 61, 67, 74, and 78% respectively at day 30. The viability and stability of microbial isolates show considerable good viability on irradiated compost carrier materials after 14 days storage. From the fours series microbial consortium, the highest TPH degradation rates is found in microbial consortium III (BMC6, BMC2, and FMC6) with 89,1% in 5 weeks. (author)

Bacterial community dynamics during bioremediation of diesel oil-contaminated Antarctic soil.

Science.gov (United States)

Vázquez, S; Nogales, B; Ruberto, L; Hernández, E; Christie-Oleza, J; Lo Balbo, A; Bosch, R; Lalucat, J; Mac Cormack, W

2009-05-01

The effect of nutrient and inocula amendment in a bioremediation field trial using a nutrient-poor Antarctic soil chronically contaminated with hydrocarbons was tested. The analysis of the effects that the treatments caused in bacterial numbers and hydrocarbon removal was combined with the elucidation of the changes occurring on the bacterial community, by 16S rDNA-based terminal restriction fragment length polymorphism (T-RFLP) typing, and the detection of some of the genes involved in the catabolism of hydrocarbons. All treatments caused a significant increase in the number of bacteria able to grow on hydrocarbons and a significant decrease in the soil hydrocarbon content, as compared to the control. However, there were no significant differences between treatments. Comparison of the soil T-RFLP profiles indicated that there were changes in the structure and composition of bacterial communities during the bioremediation trial, although the communities in treated plots were highly similar irrespective of the treatment applied, and they had a similar temporal dynamics. These results showed that nutrient addition was the main factor contributing to the outcome of the bioremediation experiment. This was supported by the lack of evidence of the establishment of inoculated consortia in soils, since their characteristic electrophoretic peaks were only detectable in soil profiles at the beginning of the experiment. Genetic potential for naphthalene degradation, evidenced by detection of nahAc gene, was observed in all soil plots including the control. In treated plots, an increase in the detection of catechol degradation genes (nahH and catA) and in a key gene of denitrification (nosZ) was observed as well. These results indicate that treatments favored the degradation of aromatic hydrocarbons and probably stimulated denitrification, at least transiently. This mesocosm study shows that recovery of chronically contaminated Antarctic soils can be successfully accelerated

A versatile class of cell surface directional motors gives rise to gliding motility and sporulation in Myxococcus xanthus.

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Morgane Wartel

2013-12-01

Full Text Available Eukaryotic cells utilize an arsenal of processive transport systems to deliver macromolecules to specific subcellular sites. In prokaryotes, such transport mechanisms have only been shown to mediate gliding motility, a form of microbial surface translocation. Here, we show that the motility function of the Myxococcus xanthus Agl-Glt machinery results from the recent specialization of a versatile class of bacterial transporters. Specifically, we demonstrate that the Agl motility motor is modular and dissociates from the rest of the gliding machinery (the Glt complex to bind the newly expressed Nfs complex, a close Glt paralogue, during sporulation. Following this association, the Agl system transports Nfs proteins directionally around the spore surface. Since the main spore coat polymer is secreted at discrete sites around the spore surface, its transport by Agl-Nfs ensures its distribution around the spore. Thus, the Agl-Glt/Nfs machineries may constitute a novel class of directional bacterial surface transporters that can be diversified to specific tasks depending on the cognate cargo and machinery-specific accessories.

Integrative computational approach for genome-based study of microbial lipid-degrading enzymes.

Science.gov (United States)

Vorapreeda, Tayvich; Thammarongtham, Chinae; Laoteng, Kobkul

2016-07-01

Lipid-degrading or lipolytic enzymes have gained enormous attention in academic and industrial sectors. Several efforts are underway to discover new lipase enzymes from a variety of microorganisms with particular catalytic properties to be used for extensive applications. In addition, various tools and strategies have been implemented to unravel the functional relevance of the versatile lipid-degrading enzymes for special purposes. This review highlights the study of microbial lipid-degrading enzymes through an integrative computational approach. The identification of putative lipase genes from microbial genomes and metagenomic libraries using homology-based mining is discussed, with an emphasis on sequence analysis of conserved motifs and enzyme topology. Molecular modelling of three-dimensional structure on the basis of sequence similarity is shown to be a potential approach for exploring the structural and functional relationships of candidate lipase enzymes. The perspectives on a discriminative framework of cutting-edge tools and technologies, including bioinformatics, computational biology, functional genomics and functional proteomics, intended to facilitate rapid progress in understanding lipolysis mechanism and to discover novel lipid-degrading enzymes of microorganisms are discussed.

Interference in Bacterial Quorum Sensing: A Biopharmaceutical Perspective

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Benjamin Rémy

2018-03-01

Full Text Available Numerous bacteria utilize molecular communication systems referred to as quorum sensing (QS to synchronize the expression of certain genes regulating, among other aspects, the expression of virulence factors and the synthesis of biofilm. To achieve this process, bacteria use signaling molecules, known as autoinducers (AIs, as chemical messengers to share information. Naturally occurring strategies that interfere with bacterial signaling have been extensively studied in recent years, examining their potential to control bacteria. To interfere with QS, bacteria use quorum sensing inhibitors (QSIs to block the action of AIs and quorum quenching (QQ enzymes to degrade signaling molecules. Recent studies have shown that these strategies are promising routes to decrease bacterial pathogenicity and decrease biofilms, potentially enhancing bacterial susceptibility to antimicrobial agents including antibiotics and bacteriophages. The efficacy of QSIs and QQ enzymes has been demonstrated in various animal models and are now considered in the development of new medical devices against bacterial infections, including dressings, and catheters for enlarging the therapeutic arsenal against bacteria.

Petroleum degrading potentials of single and mixed microbial ...

African Journals Online (AJOL)

The ability of three bacterial isolates (Bacillus spp, Micrococcus spp and Proteus spp.) and some fungal species (Penicillin spp., Aspergillus spp. and Rhizopus spp.) isolated from two rivers and refinery effluent to degrade two Nigerian Crude oils was studied. The results showed changes in pH, optical density and total ...

Degradation of Biofumigant Isothiocyanates and Allyl Glucosinolate in Soil and Their Effects on the Microbial Community Composition.

Directory of Open Access Journals (Sweden)

Franziska S Hanschen

Full Text Available Brassicales species rich in glucosinolates are used for biofumigation, a process based on releasing enzymatically toxic isothiocyanates into the soil. These hydrolysis products are volatile and often reactive compounds. Moreover, glucosinolates can be degraded also without the presence of the hydrolytic enzyme myrosinase which might contribute to bioactive effects. Thus, in the present study the stability of Brassicaceae plant-derived and pure glucosinolates hydrolysis products was studied using three different soils (model biofumigation. In addition, the degradation of pure 2-propenyl glucosinolate was investigated with special regard to the formation of volatile breakdown products. Finally, the influence of pure glucosinolate degradation on the bacterial community composition was evaluated using denaturing gradient gel electrophoresis of 16S rRNA gene amplified from total community DNA. The model biofumigation study revealed that the structure of the hydrolysis products had a significant impact on their stability in the soil but not the soil type. Following the degradation of pure 2-propenyl glucosinolate in the soils, the nitrile as well as the isothiocyanate can be the main degradation products, depending on the soil type. Furthermore, the degradation was shown to be both chemically as well as biologically mediated as autoclaving reduced degradation. The nitrile was the major product of the chemical degradation and its formation increased with iron content of the soil. Additionally, the bacterial community composition was significantly affected by adding pure 2-propenyl glucosinolate, the effect being more pronounced than in treatments with myrosinase added to the glucosinolate. Therefore, glucosinolates can have a greater effect on soil bacterial community composition than their hydrolysis products.

Rehosting of Bacterial Chaperones for High-Quality Protein Production▿

Science.gov (United States)

Martínez-Alonso, Mónica; Toledo-Rubio, Verónica; Noad, Rob; Unzueta, Ugutz; Ferrer-Miralles, Neus; Roy, Polly; Villaverde, Antonio

2009-01-01

Coproduction of DnaK/DnaJ in Escherichia coli enhances solubility but promotes proteolytic degradation of their substrates, minimizing the yield of unstable polypeptides. Higher eukaryotes have orthologs of DnaK/DnaJ but lack the linked bacterial proteolytic system. By coexpression of DnaK and DnaJ in insect cells with inherently misfolding-prone recombinant proteins, we demonstrate simultaneous improvement of soluble protein yield and quality and proteolytic stability. Thus, undesired side effects of bacterial folding modulators can be avoided by appropriate rehosting in heterologous cell expression systems. PMID:19820142

Enzymatically and reductively degradable α-amino acid-based poly(ester amide)s: Synthesis, cell compatibility, and intracellular anticancer drug delivery

NARCIS (Netherlands)

Sun, H.; Cheng, Ru; Deng, Chao; Meng, Fenghua; Dias, Aylvin A.; Hendriks, Marc; Feijen, Jan; Zhong, Zhiyuan

2015-01-01

A novel and versatile family of enzymatically and reductively degradable α-amino acid-based poly(ester amide)s (SS-PEAs) were developed from solution polycondensation of disulfide-containing di-p-toluenesulfonic acid salts of bis-l-phenylalanine diesters (SS-Phe-2TsOH) with di-p-nitrophenyl adipate

Calcium carbonate-gold nanocluster hybrid spheres: synthesis and versatile application in immunoassays.

Science.gov (United States)

Peng, Juan; Feng, Li-Na; Zhang, Kui; Li, Xing-Hua; Jiang, Li-Ping; Zhu, Jun-Jie

2012-04-23

Fluorescent gold nanoclusters (AuNCs) were incorporated into porous calcium carbonate spheres through electrostatic interaction. The resulting CaCO(3)/AuNCs hybrid material exhibited interesting properties, such as porous structure, excellent biocompatibility, good water solubility, and degradability. These properties make the CaCO(3)/AuNCs hybrid material a promising template to assemble horseradish peroxidase/antibody conjugates (HRP-Ab(2)). By using CaCO(3)/AuNCs/HRP-Ab(2) bioconjugates as probes, a versatile immunosensor was developed for fluorescent and electrochemical detection of the cancer biomarker neuron-specific enolase (NSE). The detection limits of the sensor were 2.0 and 0.1 pg mL(-1) for fluorescent and electrochemical detection, respectively. The immunosensor shows high sensitivity and offers an alternative strategy for the detection of other proteins and DNA. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Asymmetric transfer hydrogenation of ketones in aqueous solution catalyzed by Rhodium(III) complexes with C2-symmetric fluorene-ligands containing chiral (1R,2R)-cyclohexane-1,2-diamine

Energy Technology Data Exchange (ETDEWEB)

Montalvo-Gonzalez, Ruben [Universidad Autonoma de Nayarit, Tepic, Nay (Mexico). Unidad Academica de Ciencias Quimico Biologicas y Farmaceuticas; Chavez, Daniel; Aguirre, Gerardo; Parra-Hake, Miguel; Somanathan, Ratnasamy, E-mail: somanatha@sundown.sdsu.ed [Instituto Tecnologico de Tijuana, B.C. (Mexico). Centro de Graduados e Investigacion

2010-07-01

Two C{sub 2}-symmetric bis(sulfonamide) ligands containing fluorene-chiral (1R, 2R)-cyclohexane-1,2-diamine were complexed to Rh{sup III}(Cp{sup *}) and used as catalyst to reduce aromatic ketones. The corresponding chiral secondary alcohols were obtained in 87-100% ee and 85-99% yield, under asymmetric transfer hydrogenation (ATH) conditions using aqueous sodium formate as the hydride source. With acetophenone, 94% ee and 86-97% yield was achieved with substrate/catalyst (S/C) ratio of 10,000. (author)

Polymer Film-Based Screening and Isolation of Polylactic Acid (PLA)-Degrading Microorganisms.

Science.gov (United States)

Kim, Mi Yeon; Kim, Changman; Moon, Jungheun; Heo, Jinhee; Jung, Sokhee P; Kim, Jung Rae

2017-02-28

Polylactic acid (PLA) has been highlighted as an alternative renewable polymer for the replacement of petroleum-based plastic materials, and is considered to be biodegradable. On the other hand, the biodegradation of PLA by terminal degraders, such as microorganisms, requires a lengthy period in the natural environment, and its mechanism is not completely understood. PLA biodegradation studies have been conducted using mainly undefined mixed cultures, but only a few bacterial strains have been isolated and examined. For further characterization of PLA biodegradation, in this study, the PLA-degrading bacteria from digester sludge were isolated and identified using a polymer film-based screening method. The enrichment of sludge on PLA granules was conducted with the serial transference of a subculture into fresh media for 40 days, and the attached biofilm was inoculated on a PLA film on an agar plate. 3D optical microscopy showed that the isolates physically degraded the PLA film due to bacterial degradation. 16S rRNA gene sequencing identified the microbial colonies to be Pseudomonas sp. MYK1 and Bacillus sp. MYK2. The two isolates exhibited significantly higher specific gas production rates from PLA biodegradation compared with that of the initial sludge inoculum.

Studies on the physiology of microbial degradation of pentachlorophenol

Energy Technology Data Exchange (ETDEWEB)

Valo, R.; Apajalahti, J.; Salkinoja-Salonen, M.

1985-03-01

The requirements and conditions for pentachlorophenol (PCP) biodegradation by a mixed bacterial culture was studied. The effects of oxygen, nutrients, additional carbon sources, pH and temperature are described. Up to 90% of PCP was degraded into CO/sub 2/ and inorganic chloride in 1 week at an input concentration of <600 ..mu..M. Degradation continued when pO/sub 2/ was lowered to 0.0002 atm but ceased when pO/sub 2/ was further decreased to 0.00002 atm. Supplementary carbon sources, such as phenol, hydroxybenzoic acids or complex nutrients did not affect the biodegradation, but the presence of ammonium salts enhanced the rate of PCP degradation without affecting the yield of CO/sub 2/. The degrading organisms were shown to be procaryotic mesophiles; no degradation was shown at temperatures below +8/sup 0/ and above +50/sup 0/C. The optimum pH for degradation was from 6.4 to 7.2 and at higher pH value (8.4) degradation was inhibited more than at lower pH (5.6).

Transport of EDTA into cells of the EDTA-degrading bacterial strain DSM 9103.

Science.gov (United States)

Witschel, M; Egli, T; Zehnder, A J; Wehrli, E; Spycher, M

1999-04-01

In the bacterial strain DSM 9103, which is able to grow with the complexing agent EDTA as the sole source of carbon, nitrogen and energy, the transport of EDTA into whole cells was investigated. EDTA uptake was found to be dependent on speciation: free EDTA and metal-EDTA complexes with low stability constants were readily taken up, whereas those with stability constants higher than 1016 were not transported. In EDTA-grown cells, initial transport rates of CaEDTA showed substrate-saturation kinetics with a high apparent affinity for CaEDTA (affinity constant Kt= 0.39 microM). Several uncouplers had an inhibitory effect on CaEDTA transport. CaEDTA uptake was also significantly reduced in the presence of an inhibitor of ATPase and the ionophore nigericin, which dissipates the proton gradient. Valinomycin, however, which affects the electrical potential, had little effect on uptake, indicating that EDTA transport is probably driven by the proton gradient. Of various structurally related compounds tested only Ca2+-complexed diethylenetriaminepentaacetate (CaDTPA) competitively inhibited CaEDTA transport. Uptake in fumarate-grown cells was low compared to that measured in EDTA-grown bacteria. These results strongly suggest that the first step in EDTA degradation by strain DSM 9103 consists of transport by an inducible energy-dependent carrier. Uptake experiments with 45Ca2+ in the presence and absence of EDTA indicated that Ca2+ is transported together with EDTA into the cells. In addition, these transport studies and electron-dispersive X-ray analysis of electron-dense intracellular bodies present in EDTA-grown cells suggest that two mechanisms acting simultaneously allow the cells to cope with the large amounts of metal ions taken up together with EDTA. In one mechanism the metal ions are excreted, in the other they are inactivated intracellularly in polyphosphate granules.

Characterizing the collagen stabilizing effect of crosslinked chitosan nanoparticles against collagenase degradation.

Science.gov (United States)

Kishen, Anil; Shrestha, Suja; Shrestha, Annie; Cheng, Calvin; Goh, Cynthia

2016-08-01

Antibacterial and chelating properties of chitosan has been widely studied for various dental applications. To characterize the interaction between chitosan-nanoparticles (CSnp) and collagen, and understand their stabilizing effect against collagenase degradation for dentin matrix stabilization. Phase-1: a single Type I collagen-fibril model was used to study the interaction with CSnp along with carbodiimides crosslinking treatment. Degradation of the crosslinked fibrils was studied with bacterial collagenase enzyme and monitored using Fourier Transform Infrared (FTIR) spectroscopy, turbidity measurement (400nm), ninhydrin assay and Atomic Force Microscopy (AFM). Interaction of CSnp with collagenase and Type I collagen, were evaluated using SDS-PAGE, and proteolytic cleavage potential of a synthetic peptide. Phase-2: degradation of dentin collagen crosslinked with/without CSnp was evaluated using FTIR, ninhydrin assay and Scanning Electron Microscopy (SEM). Glutaraldehyde crosslinking was used as a positive control. Both native collagen-fibrils and dentin collagen after crosslinking showed higher resistance to collagenase degradation, as observed in turbidity measurements and FTIR spectra. AFM images showed the interaction of CSnp with single collagen-fibril and crosslinked collagen resisted collagenase degradation up to 54h. The collagen and collagenase both formed complexes with CSnp resulting in thickening of bands and reduction in collagen degradation. CSnp treated collagenase showed significantly reduced cleavage of the fluorescent peptides. Dentin collagen was coated with CSnp following crosslinking with significant increase in resistance to collagenase degradation. Crosslinked CSnp on collagen stabilized and enhanced the resistance of dentin matrix against bacterial collagenase degradation due to non-specific interaction with both collagen and collagenase. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Bacterial Endophytes Isolated from Plants in Natural Oil Seep Soils with Chronic Hydrocarbon Contamination.

Science.gov (United States)

Lumactud, Rhea; Shen, Shu Yi; Lau, Mimas; Fulthorpe, Roberta

2016-01-01

The bacterial endophytic communities of four plants growing abundantly in soils highly contaminated by hydrocarbons were analyzed through culturable and culture-independent means. Given their tolerance to the high levels of petroleum contamination at our study site, we sought evidence that Achillea millefolium, Solidago canadensis, Trifolium aureum, and Dactylis glomerata support high levels of hydrocarbon degrading endophytes. A total of 190 isolates were isolated from four plant species. The isolates were identified by partial 16S rDNA sequence analysis, with class Actinobacteria as the dominant group in all species except S. canadensis, which was dominated by Gammaproteobacteria. Microbacterium foliorum and Plantibacter flavus were present in all the plants, with M. foliorum showing predominance in D. glomerata and both endophytic bacterial species dominated T. aureum. More than 50% of the isolates demonstrated degradative capabilities for octanol, toluene, naphthalene, kerosene, or motor oil based on sole carbon source growth screens involving the reduction of tetrazolium dye. P. flavus isolates from all the sampled plants showed growth on all the petroleum hydrocarbons (PHCs) substrates tested. Mineralization of toluene and naphthalene was confirmed using gas-chromatography. 16S based terminal restriction fragment length polymorphism analysis revealed significant differences between the endophytic bacterial communities showing them to be plant host specific at this site. To our knowledge, this is the first account of the degradation potential of bacterial endophytes in these commonly occurring pioneer plants that were not previously known as phytoremediating plants.

Bacterial endophytes isolated from plants in natural oil seep soils with chronic hydrocarbon contamination

Directory of Open Access Journals (Sweden)

Rhea eLumactud

2016-05-01

Full Text Available The bacterial endophytic communities of four plants growing abundantly in soils highly contaminated by hydrocarbons were analyzed through culturable and and culture-independent means. Given their tolerance to the high levels of petroleum contamination at our study site, we sought evidence that Achillea millefolium, Solidago canadensis, Trifolium aureum and Dactylis glomerata support high levels of hydrocarbon degrading endophytes. A total of 190 isolates were isolated from four plant species. The isolates were identified by partial 16S rDNA sequence analysis, with class Actinobacteria as the dominant group in all species except Solidago canadensis, which was dominated by Gammaproteobacteria. Microbacterium foliorum and Plantibacter flavus were present in all the plants, with M. foliorum showing predominance in D. glomerata and both endophytic bacterial species dominated T. aureum. More than 50% of the isolates demonstrated degradative capabilities for octanol, toluene, naphthalene, kerosene or motor oil based on sole carbon source growth screens involving the reduction of tetrazolium dye. P. flavus isolates from all the sampled plants showed growth on all the petroleum hydrocarbons substrates tested. Mineralization of toluene and naphthalene was confirmed using gas-chromatography. 16S based terminal restriction fragment length polymorphism analysis revealed significant differences between the endophytic bacterial communities showing them to be plant host specific at this site. To our knowledge, this is the first account of the degradation potential of bacterial endophytes in these commonly occurring pioneer plants that were not previously known as phytoremediating plants.

Isolation and Characterization of Polyacrylamide-Degrading Bacteria from Dewatered Sludge

Directory of Open Access Journals (Sweden)

Feng Yu

2015-04-01

Full Text Available Polyacrylamide (PAM is a water-soluble polymer that is widely used as a flocculant in sewage treatment. The accumulation of PAM affects the formation of dewatered sludge and potentially produces hazardous monomers. In the present study, the bacterial strain HI47 was isolated from dewatered sludge. This strain could metabolize PAM as its sole nutrient source and was subsequently identified as Pseudomonas putida. The efficiency of PAM degradation was 31.1% in 7 days and exceeded 45% under optimum culture condition (pH 7.2, 39 °C and 100 rpm. The addition of yeast extract and glucose improved the bacterial growth and PAM degradation. The degraded PAM samples were analyzed by gel-filtration chromatography, Fourier transform infrared and high-performance liquid chromatography. The results showed that high-molecular-weight PAM was partly cleaved to small molecular oligomer derivatives and part of the amide groups of PAM had been converted to carboxyl groups. The biodegradation did not accumulate acrylamide monomers. Based on the SDS-PAGE and N-terminal sequencing results, the PAM amide groups were converted into carboxyl groups by a PAM-induced extracellular enzyme from the aliphatic amidase family.

COMETABOLIC DEGRADATION OF CHLOROALLYL ALCOHOLS IN BATCH AND CONTINUOUS CULTURES

NARCIS (Netherlands)

VANDERWAARDE, JJ; KOK, R; JANSSEN, DB; Waarde, J.J. van der

1994-01-01

The biodegradation of chloroallyl alcohols by pure and mixed bacterial cultures was investigated. Only 2-chloroallyl alcohol and cis- and trans-3-chloroallyl alcohol served as growth substrate for pure cultures. The other chloroallyl alcohols could be cometabolically degraded during growth on

Pseudomonas syringae evades host Immunity by degrading flagellin monomers with alkaline protease AprA

OpenAIRE

Pel, M.J.C.; Van Dijken, A.J.H.; Bardoel, B.W.; Seidl, M.F; Van der Ent, S.; Van Strijp, J.A.G.

2014-01-01

Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of bacterial species. In addition, we investigated the role of AprA in virulence of the bacterial plant athogen P. syringae pv. tomato DC3000. The AprA-deficient DC3000 ΔaprA knockout mutant was significantl...

Genus-wide comparison of Pseudovibrio bacterial genomes reveal diverse adaptations to different marine invertebrate hosts.

Science.gov (United States)

Alex, Anoop; Antunes, Agostinho

2018-01-01

Bacteria belonging to the genus Pseudovibrio have been frequently found in association with a wide variety of marine eukaryotic invertebrate hosts, indicative of their versatile and symbiotic lifestyle. A recent comparison of the sponge-associated Pseudovibrio genomes has shed light on the mechanisms influencing a successful symbiotic association with sponges. In contrast, the genomic architecture of Pseudovibrio bacteria associated with other marine hosts has received less attention. Here, we performed genus-wide comparative analyses of 18 Pseudovibrio isolated from sponges, coral, tunicates, flatworm, and seawater. The analyses revealed a certain degree of commonality among the majority of sponge- and coral-associated bacteria. Isolates from other marine invertebrate host, tunicates, exhibited a genetic repertoire for cold adaptation and specific metabolic abilities including mucin degradation in the Antarctic tunicate-associated bacterium Pseudovibrio sp. Tun.PHSC04_5.I4. Reductive genome evolution was simultaneously detected in the flatworm-associated bacteria and the sponge-associated bacterium P. axinellae AD2, through the loss of major secretion systems (type III/VI) and virulence/symbioses factors such as proteins involved in adhesion and attachment to the host. Our study also unraveled the presence of a CRISPR-Cas system in P. stylochi UST20140214-052 a flatworm-associated bacterium possibly suggesting the role of CRISPR-based adaptive immune system against the invading virus particles. Detection of mobile elements and genomic islands (GIs) in all bacterial members highlighted the role of horizontal gene transfer for the acquisition of novel genetic features, likely enhancing the bacterial ecological fitness. These findings are insightful to understand the role of genome diversity in Pseudovibrio as an evolutionary strategy to increase their colonizing success across a wide range of marine eukaryotic hosts.

A versatile family of degradable non-viral gene carriers based on hyperbranched poly(ester amine)s

NARCIS (Netherlands)

Zhong, Zhiyuan; Song, Y.; Engbersen, Johannes F.J.; Lok, Martin C.; Hennink, Wim E.; Feijen, Jan

2005-01-01

A variety of degradable hyperbranched poly(ester amine)s containing primary, secondary and tertiary amino groups, were synthesized and evaluated as non-viral gene carriers. The polymers were obtained in high yields through a Michael-type conjugate addition of diacrylate monomers with trifunctional

Draft Genome Sequence of MCPA-Degrading Sphingomonas sp. Strain ERG5, Isolated from a Groundwater Aquifer in Denmark

DEFF Research Database (Denmark)

Nielsen, Tue Kjærgaard; Kot, Witold; Sørensen, Sebastian R

2015-01-01

Sphingomonas sp. strain ERG5 was isolated from a bacterial community, originating from a groundwater aquifer polluted with low pesticide concentrations. This bacterium degrades 2-methyl-4-chlorophenoxyacetic acid (MCPA) in a wide spectrum of concentrations and has been shown to function in bioaug......Sphingomonas sp. strain ERG5 was isolated from a bacterial community, originating from a groundwater aquifer polluted with low pesticide concentrations. This bacterium degrades 2-methyl-4-chlorophenoxyacetic acid (MCPA) in a wide spectrum of concentrations and has been shown to function...

Bacterial carbon utilization in vertical subsurface flow constructed wetlands.

Science.gov (United States)

Tietz, Alexandra; Langergraber, Günter; Watzinger, Andrea; Haberl, Raimund; Kirschner, Alexander K T

2008-03-01

Subsurface vertical flow constructed wetlands with intermittent loading are considered as state of the art and can comply with stringent effluent requirements. It is usually assumed that microbial activity in the filter body of constructed wetlands, responsible for the removal of carbon and nitrogen, relies mainly on bacterially mediated transformations. However, little quantitative information is available on the distribution of bacterial biomass and production in the "black-box" constructed wetland. The spatial distribution of bacterial carbon utilization, based on bacterial (14)C-leucine incorporation measurements, was investigated for the filter body of planted and unplanted indoor pilot-scale constructed wetlands, as well as for a planted outdoor constructed wetland. A simple mass-balance approach was applied to explain the bacterially catalysed organic matter degradation in this system by comparing estimated bacterial carbon utilization rates with simultaneously measured carbon reduction values. The pilot-scale constructed wetlands proved to be a suitable model system for investigating microbial carbon utilization in constructed wetlands. Under an ideal operating mode, the bulk of bacterial productivity occurred within the first 10cm of the filter body. Plants seemed to have no significant influence on productivity and biomass of bacteria, as well as on wastewater total organic carbon removal.

Biodegradation of γ-hexachlorocyclohexane by transgenic hairy root cultures of Cucurbita moschata that accumulate recombinant bacterial LinA.

Science.gov (United States)

Nanasato, Yoshihiko; Namiki, Sayuri; Oshima, Masao; Moriuchi, Ryota; Konagaya, Ken-Ichi; Seike, Nobuyasu; Otani, Takashi; Nagata, Yuji; Tsuda, Masataka; Tabei, Yutaka

2016-09-01

γ-HCH was successfully degraded using LinA-expressed transgenic hairy root cultures of Cucurbita moschata . Fusing an endoplasmic reticulum-targeting signal peptide to LinA was essential for stable accumulation in the hairy roots. The pesticide γ-hexachlorocyclohexane (γ-HCH) is a persistent organic pollutant (POP) that raises public health and environmental pollution concerns worldwide. Although several isolates of γ-HCH-degrading bacteria are available, inoculating them directly into γ-HCH-contaminated soil is ineffective because of the bacterial survival rate. Cucurbita species incorporate significant amounts of POPs from soils compared with other plant species. Here, we describe a novel bioremediation strategy that combines the bacterial degradation of γ-HCH and the efficient uptake of γ-HCH by Cucurbita species. We produced transgenic hairy root cultures of Cucurbita moschata that expressed recombinant bacterial linA, isolated from the bacterium Sphingobium japonicum UT26. The LinA protein was accumulated stably in the hairy root cultures by fusing an endoplasmic reticulum (ER)-targeting signal peptide to LinA. Then, we demonstrated that the cultures degraded more than 90 % of γ-HCH (1 ppm) overnight and produced the γ-HCH metabolite 1,2,4-trichlorobenzene, indicating that LinA degraded γ-HCH. These results indicate that the gene linA has high potential for phytoremediation of environmental γ-HCH.

Monitoring of oil pollution at Gemsa Bay and bioremediation capacity of bacterial isolates with biosurfactants and nanoparticles.

Science.gov (United States)

El-Sheshtawy, H S; Khalil, N M; Ahmed, W; Abdallah, R I

2014-10-15

Fifteen crude oil-degrading bacterial isolates were isolated from an oil-polluted area in Gemsa Bay, Red Sea, Egypt. Two bacterial species showed the highest growth rate on crude oil hydrocarbons. From an analysis of 16S rRNA sequences, these isolates were identified as Pseudomonas xanthomarina KMM 1447 and Pseudomonas stutzeri ATCC 17588. Gas Chromatographic (GC) analysis of the crude oil remaining in the culture medium after one week at 30°C showed that the optimum biodegradation of crude petroleum oil was demonstrated at 50% in medium containing biosurfactant with two types of nanoparticles separately and two bacterial species. The complete degradation of some different members of polyaromatics and the percentage biodegradation of other polyaromatics increased in microcosm containing two different types of nanoparticles with biosurfactant after 7 days. In conclusion, these bacterial strains may be useful for the bioremediation process in the Gemsa Bay, Red Sea decreasing oil pollution in this marine ecosystem. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biodegradation evaluation of bacterial cellulose, vegetable cellulose and poly (3-hydroxybutyrate in soil

Directory of Open Access Journals (Sweden)

Suellen Brasil Schröpfer

2015-04-01

Full Text Available In recent years, the inappropriate disposal of polymeric materials has increased due to industrial development and increase of population consumption. This problem may be minimized by using biodegradable polymers, such as bacterial cellulose and poly(hydroxybutyrate, from renewable resources. This work was aimed at monitoring and evaluating degradation of bacterial cellulose, vegetable cellulose and poly(3-hydroxybutyrate using Thermogravimetric Analysis and Scanning Electron Microscopy. Controlled mass polymer samples were buried in pots containing soil. Samples were removed in 30 day intervals up to 180 days. The results show that the mass of the polymer increased in the first month when in contact with the soil but then it was degraded as evidenced by mass loss and changes on the sample surface.

Crude oil treatment leads to shift of bacterial communities in soils from the deep active layer and upper permafrost along the China-Russia Crude Oil Pipeline route.

Science.gov (United States)

Yang, Sizhong; Wen, Xi; Zhao, Liang; Shi, Yulan; Jin, Huijun

2014-01-01

The buried China-Russia Crude Oil Pipeline (CRCOP) across the permafrost-associated cold ecosystem in northeastern China carries a risk of contamination to the deep active layers and upper permafrost in case of accidental rupture of the embedded pipeline or migration of oil spills. As many soil microbes are capable of degrading petroleum, knowledge about the intrinsic degraders and the microbial dynamics in the deep subsurface could extend our understanding of the application of in-situ bioremediation. In this study, an experiment was conducted to investigate the bacterial communities in response to simulated contamination to deep soil samples by using 454 pyrosequencing amplicons. The result showed that bacterial diversity was reduced after 8-weeks contamination. A shift in bacterial community composition was apparent in crude oil-amended soils with Proteobacteria (esp. α-subdivision) being the dominant phylum, together with Actinobacteria and Firmicutes. The contamination led to enrichment of indigenous bacterial taxa like Novosphingobium, Sphingobium, Caulobacter, Phenylobacterium, Alicylobacillus and Arthrobacter, which are generally capable of degrading polycyclic aromatic hydrocarbons (PAHs). The community shift highlighted the resilience of PAH degraders and their potential for in-situ degradation of crude oil under favorable conditions in the deep soils.

Crude oil treatment leads to shift of bacterial communities in soils from the deep active layer and upper permafrost along the China-Russia Crude Oil Pipeline route.

Directory of Open Access Journals (Sweden)

Sizhong Yang

Full Text Available The buried China-Russia Crude Oil Pipeline (CRCOP across the permafrost-associated cold ecosystem in northeastern China carries a risk of contamination to the deep active layers and upper permafrost in case of accidental rupture of the embedded pipeline or migration of oil spills. As many soil microbes are capable of degrading petroleum, knowledge about the intrinsic degraders and the microbial dynamics in the deep subsurface could extend our understanding of the application of in-situ bioremediation. In this study, an experiment was conducted to investigate the bacterial communities in response to simulated contamination to deep soil samples by using 454 pyrosequencing amplicons. The result showed that bacterial diversity was reduced after 8-weeks contamination. A shift in bacterial community composition was apparent in crude oil-amended soils with Proteobacteria (esp. α-subdivision being the dominant phylum, together with Actinobacteria and Firmicutes. The contamination led to enrichment of indigenous bacterial taxa like Novosphingobium, Sphingobium, Caulobacter, Phenylobacterium, Alicylobacillus and Arthrobacter, which are generally capable of degrading polycyclic aromatic hydrocarbons (PAHs. The community shift highlighted the resilience of PAH degraders and their potential for in-situ degradation of crude oil under favorable conditions in the deep soils.

Crude Oil Treatment Leads to Shift of Bacterial Communities in Soils from the Deep Active Layer and Upper Permafrost along the China-Russia Crude Oil Pipeline Route

Science.gov (United States)

Yang, Sizhong; Wen, Xi; Zhao, Liang; Shi, Yulan; Jin, Huijun

2014-01-01

The buried China-Russia Crude Oil Pipeline (CRCOP) across the permafrost-associated cold ecosystem in northeastern China carries a risk of contamination to the deep active layers and upper permafrost in case of accidental rupture of the embedded pipeline or migration of oil spills. As many soil microbes are capable of degrading petroleum, knowledge about the intrinsic degraders and the microbial dynamics in the deep subsurface could extend our understanding of the application of in-situ bioremediation. In this study, an experiment was conducted to investigate the bacterial communities in response to simulated contamination to deep soil samples by using 454 pyrosequencing amplicons. The result showed that bacterial diversity was reduced after 8-weeks contamination. A shift in bacterial community composition was apparent in crude oil-amended soils with Proteobacteria (esp. α-subdivision) being the dominant phylum, together with Actinobacteria and Firmicutes. The contamination led to enrichment of indigenous bacterial taxa like Novosphingobium, Sphingobium, Caulobacter, Phenylobacterium, Alicylobacillus and Arthrobacter, which are generally capable of degrading polycyclic aromatic hydrocarbons (PAHs). The community shift highlighted the resilience of PAH degraders and their potential for in-situ degradation of crude oil under favorable conditions in the deep soils. PMID:24794099

Amylase activity of a starch degrading bacteria isolated from soil ...

African Journals Online (AJOL)

Starch degrading bacteria are most important for industries such as food, fermentation, textile and paper. Thus isolating and manipulating pure culture from various waste materials has manifold importance for various biotechnology industries. In the present investigation a bacterial strain was isolated from soil sample ...

Continuous exposure of pesticides in an aquifer changes microbial biomass, diversity and degradation potential

DEFF Research Database (Denmark)

de Lipthay, J. R.; Johnsen, K.; Aamand, J.

2000-01-01

We studied in situ effects of pesticide exposure on microbial degradation potential and community structure of aquifer sediments. Sediment samples pre-exposed to pesticides were significantly different to non-exposed control samples. Pre-exposed sediment showed an increased degradation potential ...... towards phenoxyalcanoic acid herbicides as well as impact on microbial diversity was observed. Furthermore, bacterial biomass was changed, e.g. increased numbers of phenoxyalcanoic acid degraders in pesticide exposed sediment.......We studied in situ effects of pesticide exposure on microbial degradation potential and community structure of aquifer sediments. Sediment samples pre-exposed to pesticides were significantly different to non-exposed control samples. Pre-exposed sediment showed an increased degradation potential...

Zinc-Triggered Hydrogelation of Self-assembled Small Molecules to Inhibit Bacterial Growth

Science.gov (United States)

Xu, Chao; Cai, Yanbin; Ren, Chunhua; Gao, Jie; Hao, Jihui

2015-01-01

There is a significant need to develop antibacterial materials that could be applied locally and directly to the places surrounded by large amount of bacteria, in order to address the problems of bacterial antibiotic-resistance or irreversible biofilm formation. Hydrogels are thought to be suitable candidates due to their versatile applications in biomedical field. Among them, small molecular hydrogels have been paid lots of attention because they are easy to design and fabricate and often sensitive to external stimuli. Meanwhile, the antibacterial activity of metal ions are attracting more and more attention because resistance to them are not yet found within bacteria. We therefore designed the zinc ion binding peptide of Nap-GFFYGGGHGRGD, who can self-assemble into hydrogels after binds Zn2+ and inhibit the growth of bacteria due to the excellent antibacterial activity of Zn2+. Upon the addition of zinc ions, solutions containing Nap-GFFYGGGHGRGD transformed into supramolecular hydrogels composed of network of long nano-fibers. Bacterial tests revealed an antibacterial effect of the zinc triggered hydrogels on E. coli. The studied small molecular hydrogel shows great potential in locally addressing bacterial infections.

Marine microbe with potential to adhere and degrade plastic structures

Directory of Open Access Journals (Sweden)

Alka Kumari

2017-10-01

Full Text Available Extensive usages of plastics have led to their accumulation as a contaminant in natural environment worldwide. Plastic is an inert and non-biodegradable material, due to its complex structure and hydrophobic backbone [1]. Conventional methods for reduction of plastic waste such as burning, land-filling release unwanted toxic chemicals to the environment and harming living organism of land as well as the ocean. There is growing interest in development of strategies for the degradation of plastic wastes to clean the environment [2]. Marine bacteria have evolved with the capability to adapt and grow in the diverse environmental conditions [3]. We studied the ability of marine bacteria for destabilization and utilization of different plastic films (LDPE, HDPE, PVC and PET as a sole source of carbon. An active bacterial strain AIIW2 was selected based on the triphenyl tetrazolium chloride reduction assay, and it was identified as Bacillus species based on 16S rRNA gene sequence. The viability of the strain over the plastic surface was studied and confirmed by bacLight assay with fluorescent probes. Scanning Electron Microscope and Atomic Force Microscope images suggested that bacterial interaction over the plastic surface is causing deterioration and roughness with increasing bacterial incubation time. In Fourier transform infrared spectra of treated plastic film evidenced stretching of the (-CH alkane rock chain and (-CO carbonyl region, suggested the oxidative activities of the bacteria. The results revealed that ability of bacterial strain for instigating their colonization over plastic films and deteriorating the polymeric structure in the absence of other carbon sources [4]. Moreover, production of extracellular enzymes such as esterase, laccase, and dehalogenase which are reported to support utilization of plastics was confirmed by plate assays. In concise, our results suggested that the marine bacterial strain AIIW2 have the ability to utilize

Demodex-associated bacterial proteins induce neutrophil activation.

LENUS (Irish Health Repository)

2012-02-01

Background: Patients with rosacea demonstrate a higher density of Demodex mites in their skin than controls. A bacterium isolated from a Demodex mite from a patient with papulopustular rosacea (PPR) was previously shown to provoke an immune response in patients with PPR or ocular rosacea thus suggesting a possible role for bacterial proteins in the etiology of this condition. Objectives: To examine the response of neutrophils to proteins derived from a bacterium isolated from a Demodex mite. Methods: Bacterial cells were lysed and proteins were partially purified by AKTA-FPLC. Isolated neutrophils were exposed to bacterial proteins and monitored for alterations in migration, degranulation and cytokine production. Results: Neutrophils exposed to proteins from Bacillus cells demonstrated increased levels of migration and elevated release of MMP-9, an enzyme known to degrade collagen and cathelicidin, an antimicrobial peptide. In addition neutrophils exposed to the bacterial proteins demonstrated elevated rates of Il-8 and TNF-alpha production. Conclusions: Proteins produced by a bacterium isolated from a Demodex mite have the ability to increase the migration, degranulation and cytokine production abilities of neutrophils. These results suggest that bacteria may play a role in the inflammatory erythema associated with rosacea.

Effectiveness of a model constructed wetland system containing Cyperus papyrus in degrading diesel oil

Science.gov (United States)

Harbowo, Danni Gathot; Choesin, Devi Nandita

2014-03-01

Synergism between wetland systems and the provision of degrading bacterial inoculum is now being developed for the recovery of areas polluted waters of pollutants. In connection with the frequent cases of diesel oil pollution in the waters of Indonesia, we need a way of water treatment as an efficient. In this study conducted a series of tests to develop an construcred wetland design that can effectively degrade diesel oil. Tested five systems: blanko (A), substrated, without bacterial inoculums, and vegetation (B); with the addition of inoculum (C); subsrated and vegetated (D); substrated and vegetated with the addition of inoculum (E). Vegetation used in this study is Cyperus papyrus because it has the ability to absorb pollutants. Inoculum used was Pseudomonas aeruginosa and Enterobacter aerogenes which is a bacteria degrading organic compounds commonly found in water. To measure the effectiveness of the system, use several indicators to see the degradation of pollutants, namely changes in viscosity, surface tension of pollutants, and the emergence of compound degradation. Based on the results of the study can be determined that the substrated and vegetated system with Cyperus papyrus inoculum (E) was considered the most capable of degrading diesel oil due to the large changes in all parameters. In the system E, 40.6% increase viscosity, surface tension decreased 32.7%, the appearance of degradation compounds with relatively 3614.7 points, and increased to 227.8% TDS. In addition the environmental conditions in the system E also supports the growth of vegetation and degrading microbes.

Corexit 9500 Enhances Oil Biodegradation and Changes Active Bacterial Community Structure of Oil-Enriched Microcosms.

Science.gov (United States)

Techtmann, Stephen M; Zhuang, Mobing; Campo, Pablo; Holder, Edith; Elk, Michael; Hazen, Terry C; Conmy, Robyn; Santo Domingo, Jorge W

2017-05-15

To better understand the impacts 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 5 and 25°C using both DNA and RNA extracts as the sequencing templates. Oil biodegradation patterns in both 5 and 25°C enrichments were consistent with those reported in the literature (i.e., aliphatics were degraded faster than aromatics). Slight increases in biodegradation were observed in the presence of Corexit at both temperatures. Differences in community structure were observed between treatment conditions in the DNA-based libraries. The 25°C consortia were dominated by Vibrio , Idiomarina , Marinobacter , Alcanivorax , and Thalassospira species, while the 5°C consortia were dominated by several species of the genera Flavobacterium , Alcanivorax , and Oleispira Most of these genera have been linked to hydrocarbon degradation and have been observed after oil spills. Colwellia and Cycloclasticus , known aromatic degraders, were also found in these enrichments. The addition of Corexit did not have an effect on the active bacterial community structure of the 5°C consortia, while at 25°C, a decrease in the relative abundance of Marinobacter was observed. At 25°C, Thalassospira , Marinobacter , and Idiomarina were present at higher relative abundances in the RNA than DNA libraries, suggesting that they were active in degradation. Similarly, Oleispira was greatly stimulated by the addition of oil at 5°C. IMPORTANCE While dispersants such as Corexit 9500 can be used to treat oil spills, there is still debate on the effectiveness on enhancing oil biodegradation and its potential toxic effect on oil-degrading microbial communities. The results of this study provide some insights on the microbial dynamics of hydrocarbon-degrading bacterial populations in the presence of Corexit 9500. Operational taxonomic unit (OTU) analyses

Culture-based Identification Of Microcystin-Degrading Bacteria In the Sandusky Bay and Maumee Bay of Lake Erie

Science.gov (United States)

Ormiston, A.; Mou, X.

2012-12-01

Harmful cyanobacteria blooms (cyanoHABs) are a serious issue that affects wildlife, human health, recreation and local economics worldwide. CyanoHABs produce cyanotoxins, such as microcystins (MCs) that lead to skin irritation, illness and liver tumors. Bacterially mediated degradation of MCs plays a key role to transform these toxic substrates to less harmful metabolites in natural environments. However, only a few Sphingomonos species have been isolated for degradation of MCs and many of which are from other habitats such as water plants. This project aims to isolate and identify bacteria that can degrade MC-LR and MC-RR, two major forms of MCs found during cyanoHABs in Lake Erie. Water samples were collected from the surface of Sandusky Bay and Maumee Bay of Lake Erie and immediately filtered through 3.0 -μm-pore-size membrane filters to obtain bacterioplankton fraction. The filtrates were amended with excessive inorganic nitrogen and phosphorus compounds and incubated in the dark for a week to purposely establish a carbon-limited condition. Afterwards, enrichment microcosms were established in flasks filled with pre-incubated bacterioplankton and single MC compounds (final concentration 10 μM). Once cell growth was confirmed by flow cytometry-based cell counting, bacterial cells in enriched microcosms were transferred onto solid surfaces, i.e., GFF filter and noble agar for colony isolation. Obtained single colonies were inoculated in defined liquid media with MCs as single carbon source. DNA was extracted from each purified isolate and analyzed by restriction fragment length polymorphism analysis (RFLP). A total of 18 different RFLP banding patterns were found, indicating MC-degrading bacteria may be heterogeneous in studied water samples. 16S rRNA genes of selected bacterial isolates were PCR amplified and sequenced for taxonomic identification. Our results demonstrated that MCs can be degraded by multiple bacterial species in Lake Erie. Future directions

Spectroscopic investigation of the interfaces in new poly(9,9-dihexyl–9H-fluorene-2,7- diyl based electroluminescent devices

Directory of Open Access Journals (Sweden)

C. Donitsi

2014-01-01

Full Text Available The highest occupied and lowest unoccupied states of the new electroluminescent material poly(9,9-dihexyl–9H- fluorene-2,7-diyl (PPV-D and polyvinylcarbazole (PVK are investigated using ultraviolet photoelectron and inverse photoemission spectroscopies. Hole injection barriers are determined for interfaces between indium-tin oxide covered substrates with work function ranging from 4.4 to 4.7 eV and these two polymers. Vacuum level alignment with flat bands away from the interface is found when the interface hole barrier is 0.6 eV or larger. Band bending away from the Fermi level occurs when the hole barrier is smaller than 0.6 eV. This is due to the accumulation charges at the interface with the polymer when the injection barrier is small. The resulting field bends the polymer levels to limit charge incoming in the bulk of the film. The efficiency of the electroluminescent structures is strongly influenced by the different energy levels alignment at the layer interfaces.

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

Manipulation of host membranes by the bacterial pathogens Listeria, Francisella, Shigella and Yersinia.

Science.gov (United States)

Pizarro-Cerdá, Javier; Charbit, Alain; Enninga, Jost; Lafont, Frank; Cossart, Pascale

2016-12-01

Bacterial pathogens display an impressive arsenal of molecular mechanisms that allow survival in diverse host niches. Subversion of plasma membrane and cytoskeletal functions are common themes associated to infection by both extracellular and intracellular pathogens. Moreover, intracellular pathogens modify the structure/stability of their membrane-bound compartments and escape degradation from phagocytic or autophagic pathways. Here, we review the manipulation of host membranes by Listeria monocytogenes, Francisella tularensis, Shigella flexneri and Yersinia spp. These four bacterial model pathogens exemplify generalized strategies as well as specific features observed during bacterial infection processes. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Vertical and horizontal assemblage patterns of bacterial communities in a eutrophic river receiving domestic wastewater in southeast China.

Science.gov (United States)

Gao, Yan; Wang, Chengcheng; Zhang, Weiguo; Di, Panpan; Yi, Neng; Chen, Chengrong

2017-11-01

Bacterial communities in rivers receiving untreated domestic wastewater may show specific spatial assemblage patterns due to a wide range of physicochemical conditions created by periodic algal bloom. However, there are significant gaps in understanding environmental forces that drive changes in microbial assemblages in polluted rivers. In this study, we applied high-throughput sequencing of 16S rRNA gene amplicons to perform comprehensive spatio-temporal profiling of bacterial community structure in a local river segment receiving domestic wastewater discharge in southeast China. Multivariate statistics were then used to analyse links between bacterial community structure and environmental factors. Non-metric multidimensional scaling (NMDS) plots showed that the bacterial community structure was different between upstream and downstream sections of the river. While the upstream water contained a high proportion of bacteria degrading xenobiotic aromatic compounds, the downstream water experiencing stronger algal bloom had a more diverse bacterial community which included the genus Aeromonas comprising 14 species, most of which are human pathogens. Least discriminant analysis (LDA) effect size revealed that the surface water was mainly inhabited by aerobic microorganisms capable of degrading aromatic compounds, and also contained bacterial genera including pathogenic species. In contrast, in the bottom water we found, along with aromatic compound-degrading species, anaerobic denitrifiers and Fe 3+ -reducing and fermentative bacteria. Variance partitioning canonical correspondence analysis (VPA) showed that nutrient ratios had a stronger contribution to bacterial dissimilarities than other major physicochemical factors (temperature, pH, dissolved oxygen, total organic carbon, and chlorophyll a). These results show that microbial communities in rivers continuously receiving domestic wastewater have specific longitudinal and vertical assemblage patterns and may contain

Fundamental and future prospects of printed ambipolar fluorene-type polymer light-emitting transistors for improved external quantum efficiency, mobility, and emission pattern

Science.gov (United States)

Kajii, Hirotake

2018-05-01

In this review, we focus on the improved external quantum efficiency, field-effect mobility, and emission pattern of top-gate-type polymer light-emitting transistors (PLETs) based on ambipolar fluorene-type polymers. A low-temperature, high-efficiency, printable red phosphorescent PLET based on poly(alkylfluorene) with modified alkyl side chains fabricated by a film transfer process is demonstrated. Device fabrication based on oriented films leads to an improved EL intensity owing to the increase in field-effect mobility. There are three factors that affect the transport of carriers, i.e., the energy level, threshold voltage, and mobility of each layer for heterostructure PLETs, which result in various emission patterns such as the line-shaped, multicolor and in-plane emission pattern in the full-channel area between source and drain electrodes. Fundamentals and future prospects in heterostructure devices are discussed and reviewed.

Environmental versatility promotes modularity in genome-scale metabolic networks.

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Samal, Areejit; Wagner, Andreas; Martin, Olivier C

2011-08-24

The ubiquity of modules in biological networks may result from an evolutionary benefit of a modular organization. For instance, modularity may increase the rate of adaptive evolution, because modules can be easily combined into new arrangements that may benefit their carrier. Conversely, modularity may emerge as a by-product of some trait. We here ask whether this last scenario may play a role in genome-scale metabolic networks that need to sustain life in one or more chemical environments. For such networks, we define a network module as a maximal set of reactions that are fully coupled, i.e., whose fluxes can only vary in fixed proportions. This definition overcomes limitations of purely graph based analyses of metabolism by exploiting the functional links between reactions. We call a metabolic network viable in a given chemical environment if it can synthesize all of an organism's biomass compounds from nutrients in this environment. An organism's metabolism is highly versatile if it can sustain life in many different chemical environments. We here ask whether versatility affects the modularity of metabolic networks. Using recently developed techniques to randomly sample large numbers of viable metabolic networks from a vast space of metabolic networks, we use flux balance analysis to study in silico metabolic networks that differ in their versatility. We find that highly versatile networks are also highly modular. They contain more modules and more reactions that are organized into modules. Most or all reactions in a module are associated with the same biochemical pathways. Modules that arise in highly versatile networks generally involve reactions that process nutrients or closely related chemicals. We also observe that the metabolism of E. coli is significantly more modular than even our most versatile networks. Our work shows that modularity in metabolic networks can be a by-product of functional constraints, e.g., the need to sustain life in multiple

Environmental versatility promotes modularity in genome-scale metabolic networks

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Wagner Andreas

2011-08-01

Full Text Available Abstract Background The ubiquity of modules in biological networks may result from an evolutionary benefit of a modular organization. For instance, modularity may increase the rate of adaptive evolution, because modules can be easily combined into new arrangements that may benefit their carrier. Conversely, modularity may emerge as a by-product of some trait. We here ask whether this last scenario may play a role in genome-scale metabolic networks that need to sustain life in one or more chemical environments. For such networks, we define a network module as a maximal set of reactions that are fully coupled, i.e., whose fluxes can only vary in fixed proportions. This definition overcomes limitations of purely graph based analyses of metabolism by exploiting the functional links between reactions. We call a metabolic network viable in a given chemical environment if it can synthesize all of an organism's biomass compounds from nutrients in this environment. An organism's metabolism is highly versatile if it can sustain life in many different chemical environments. We here ask whether versatility affects the modularity of metabolic networks. Results Using recently developed techniques to randomly sample large numbers of viable metabolic networks from a vast space of metabolic networks, we use flux balance analysis to study in silico metabolic networks that differ in their versatility. We find that highly versatile networks are also highly modular. They contain more modules and more reactions that are organized into modules. Most or all reactions in a module are associated with the same biochemical pathways. Modules that arise in highly versatile networks generally involve reactions that process nutrients or closely related chemicals. We also observe that the metabolism of E. coli is significantly more modular than even our most versatile networks. Conclusions Our work shows that modularity in metabolic networks can be a by-product of functional

Isolation and characterization of a novel 2-methyl-4-chlorophenoxyacetic acid-degrading Enterobacter sp. strain SE08.

Science.gov (United States)

Tan, Lin; Hu, Qiulong; Xiong, Xingyao; Su, Xiaojun; Huang, Yanning; Jiang, Ziwei; Zhou, Qingming; Zhao, Songyi; Zeng, Wei-ai

2013-10-01

A bacterial strain (SE08) capable of utilizing 2-methyl-4-chlorophenoxy acetic acid (MCPA) as the sole carbon and energy source for growth was isolated by continuous enrichment culturing in minimal salt medium (MSM) from a long term MCPA exposed soil. This bacterial strain was identified as Enterobacter sp. based on morphological, physiological and biochemical tests, as well as 16S rRNA sequence analysis. Its ability to degrade MCPA was determined using high performance liquid chromatography. The strain SE08 can tolerate unusually high MCPA concentrations (125-2000mg/L). The influences of culturing factors (initial concentration, pH, and temperature) on the bacterial growth and substrate degradation were studied. The results showed that the optimal MCPA degradation occurred at an MCPA concentration of 500mg/L, 30°C and pH 6.0. Under these conditions, 68.5 percent of MCPA in MSM was degraded by SE08, and the OD600nm reached 0.64 after culturing for 72h. The degradation of MCPA could be enhanced by addition of both carbon and nitrogen sources. At an initial MCPA concentration of 500mg/L, when 5g/L glucose and 2.5g/L yeast extract were added into the MSM media, the MCPA degradation was significantly increased to 83.8 percent, and OD600nm was increased to 1.09 after incubation at 30°C and pH 6.0 for 72h. This is the first study showing that an Enterobacter sp. strain is capable of degrading MCPA, which might provide a new approach for the remediation of MCPA contaminated soil and contribute to the limited knowledge about the function of Enterobacter species. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Isolation of imidacloprid degrading bacteria from industrial sites

International Nuclear Information System (INIS)

Shahid, M.N.; Jabeen, F.

2009-01-01

Immidacloprid is a cyclodiene organochlorine used as an insecticide all over the world and possessing a serous environmental threat. It is mostly used for cotton insects (bollworm, aphid and white fly). For isolation of imidacloprid degrading bacteria, two soil samples were collected from industrial contaminated sites of Kala Shah Kahu district sheikupura, having ten year history of use. Soil samples were analyzed by measuring pH and electric conductivity. The isolation of imidacroprid degrading bacteria was performed by enrichment technique. Eight bacterial strains, S/sub 1-a/ S/2-2-b/ S/2-c/ S/2-d/ S/2-e/ S/sub 2-f/ and S/sub 2-g/ and S/sub e-a/ were isolated on the basis of their colony morphologies. The purified colonies were characterized morphologically, physiologically and biochemically. Gram staining was done and Gram negative strain were confirmed on MacConkey agar and Eosin Methylene Blue. Bacterial strains were also checked for different minimal media in which only carbon source was the imidcloprid. For this purpose. FTW, FTW without N/sub 2/ NSM, M/sub 9/ and MM/sub 2/ media were used and their optical densities were taken on spectrophotometer isolates were checked for resistance to antibiotics and heavy metals. On these characteristics, S/sub 2-d/ and S/sub c-a/ were assigned to Enterobacteriaceae, S/sub 2-b/ to Pseudomonad and rest of the bacterial isolates were affiliated to bacillaceae. (author)

Fungal degradation of polyhydroxyalkanoates and a semiquantitative assay for screening their degradation by terrestrial fungi.

Science.gov (United States)

Matavulj, M; Molitoris, H P

1992-12-01

The current problems with decreasing fossile resources and increasing environmental pollution by petrochemical-based plastics have stimulated investigations to find biosynthetic materials which are also biodegradable. Bacterial reserve materials such as polyhydroxyalkanoates (PHA) have been discovered to possess thermoplastic properties and can be synthesized from renewable resources. Poly-beta-hydroxybutyric acid (PHB) is at present the most promising PHA; and BIOPOL, its copolymer with poly-beta-hydroxy-valerate (PHV), is already industrially produced (ICI, UK), and used as packaging material (WELLA, FRG). According to the literature, PHA degradation has so far mainly been observed in bacteria; only under certain environmental conditions has fungal degradation of PHAs been indicated. Since fungi constitute an important part of microbial populations participating in degradation processes, a simple screening method for fungal degradation of BIOPOL, a PHA-based plastic, was developed. Several media with about 150 fungal strains from different terrestrial environments and belonging to different systematic and ecological groups were used. PHA depolymerization was tested on three PHB-based media, each with 0.1% BIOPOL or PHB homopolymer causing turbidity of the medium. The media contained either a comparatively low or high content of organic carbon (beside PHA) or were based on mineral medium with PHA as the principal source of carbon. The degradation activity was detectable due to formation of a clear halo around the colony (Petri plates) or a clear zone under the colony (test tubes).(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of a Pyrethroid-Degrading Pseudomonas fulva Strain P31 and Biochemical Degradation Pathway of D-Phenothrin

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Jingjing Yang

2018-05-01

Full Text Available D-phenothrin is one of the most popular pyrethroid insecticides for its broad spectrum and high insecticidal activity. However, continuous use of D-phenothrin has resulted in serious environmental contamination and raised public concern about its impact on human health. Biodegradation of D-phenothrin has never been investigated and its metabolic behaviors remain unknown. Here, a novel bacterial strain P31 was isolated from active sludge, which completely degraded (100% D-phenothrin at 50 mg⋅L-1 in 72 h. Based on the morphology, 16S rRNA gene and Biolog tests, the strain was identified as Pseudomonas fulva. Biodegradation conditions were optimized as 29.5°C and pH 7.3 by utilizing response surface methodology. Strain P31 depicted high tolerance and strong D-phenothrin degradation ability through hydrolysis pathway. Strain P31 degraded D-phenothrin at inhibition constant (Ki of 482.1673 mg⋅L-1 and maximum specific degradation constant (qmax of 0.0455 h-1 whereas critical inhibitor concentration remained as 41.1189 mg⋅L-1. The 3-Phenoxybenzaldehyde and 1,2-benzenedicarboxylic butyl dacyl ester were identified as the major intermediate metabolites of D-phenothrin degradation pathway through high-performance liquid chromatography and gas chromatography-mass spectrometry. Bioaugmentation of D-phenothrin-contaminated soils with strain P31 dramatically enhanced its degradation, and over 75% of D-phenothrin was removed from soils within 10 days. Moreover, the strain illustrated a remarkable capacity to degrade other synthetic pyrethroids, including permethrin, cyhalothrin, β-cypermethrin, deltamethrin, fenpropathrin, and bifenthrin, exhibiting great potential in bioremediation of pyrethroid-contaminated environment.

Degradation potential and microbial community structure of heavy oil-enriched microbial consortia from mangrove sediments in Okinawa, Japan.

Science.gov (United States)

Bacosa, Hernando P; Suto, Koichi; Inoue, Chihiro

2013-01-01

Mangroves constitute valuable coastal resources that are vulnerable to oil pollution. One of the major processes to remove oil from contaminated mangrove sediment is microbial degradation. A study on heavy oil- and hydrocarbon-degrading bacterial consortia from mangrove sediments in Okinawa, Japan was performed to evaluate their capacity to biodegrade and their microbial community composition. Surface sediment samples were obtained from mangrove sites in Okinawa (Teima, Oura, and Okukubi) and enriched with heavy oil as the sole carbon and energy source. The results revealed that all enriched microbial consortia degraded more than 20% of heavy oil in 21 days. The K1 consortium from Okukubi site showed the most extensive degradative capacity after 7 and 21 days. All consortia degraded more than 50% of hexadecane but had little ability to degrade polycyclic aromatic hydrocarbons (PAHs). The consortia were dominated by Pseudomonas or Burkholderia. When incubated in the presence of hydrocarbon compounds, the active bacterial community shifted to favor the dominance of Pseudomonas. The K1 consortium was a superior degrader, demonstrating the highest ability to degrade aliphatic and aromatic hydrocarbon compounds; it was even able to degrade heavy oil at a concentration of 15%(w/v). The dominance and turn-over of Pseudomonas and Burkholderia in the consortia suggest an important ecological role for and relationship between these two genera in the mangrove sediments of Okinawa.

A versatile electrical penetration design qualified to IEEE Std. 317-1983

International Nuclear Information System (INIS)

Lankenau, W.; Wetherill, T.M.

1994-01-01

Although worldwide demand for new construction of nuclear power stations has been on a decline, the available opportunities for the design and construction of qualified electrical penetrations continues to offer challenges, requiring a highly versatile design. Versatility is necessary in order to meet unique customer requirements within the constraints of a design basis qualified to IEEE Std. 317-1983. This paper summarizes such a versatile electrical penetration designed, built and tested to IEEE Std. 317-1983. The principal features are described including major materials of construction. Some of the design constraints such as sealing requirements, and conductor density (including numerical example) are discussed. The requirements for qualification testing of the penetration assembly to IEEE Std. 317-1983 are delineated in a general sense, and some typical test ranges for preconditioning, radiation exposure, and LOCA are provided. The paper concludes by describing ways in which this versatile design has been adapted to meet unique customer requirements in a variety of nuclear power plants

Chemotaxis and degradation of organophosphate compound by a novel moderately thermo-halo tolerant Pseudomonas sp. strain BUR11: evidence for possible existence of two pathways for degradation

OpenAIRE

Pailan, Santanu; Saha, Pradipta

2015-01-01

An organophosphate (OP) degrading chemotactic bacterial strain BUR11 isolated from an agricultural field was identified as a member of Pseudomonas genus on the basis of its 16S rRNA gene sequence. The strain could utilize parathion, chlorpyrifos and their major hydrolytic intermediates as sole source of carbon for its growth and exhibited positive chemotactic response towards most of them. Optimum concentration of parathion for its growth was recorded to be 200 ppm and 62% of which was degrad...

A versatile scalable PET processing system

International Nuclear Information System (INIS)

Dong, H.; Weisenberger, A.; McKisson, J.; Wenze, Xi; Cuevas, C.; Wilson, J.; Zukerman, L.

2011-01-01

Positron Emission Tomography (PET) historically has major clinical and preclinical applications in cancerous oncology, neurology, and cardiovascular diseases. Recently, in a new direction, an application specific PET system is being developed at Thomas Jefferson National Accelerator Facility (Jefferson Lab) in collaboration with Duke University, University of Maryland at Baltimore (UMAB), and West Virginia University (WVU) targeted for plant eco-physiology research. The new plant imaging PET system is versatile and scalable such that it could adapt to several plant imaging needs - imaging many important plant organs including leaves, roots, and stems. The mechanical arrangement of the detectors is designed to accommodate the unpredictable and random distribution in space of the plant organs without requiring the plant be disturbed. Prototyping such a system requires a new data acquisition system (DAQ) and data processing system which are adaptable to the requirements of these unique and versatile detectors.

Microbial Hydrocarbon and ToxicPollutant Degradation Method

Energy Technology Data Exchange (ETDEWEB)

Schlueter, Dietrich [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Janabi, Mustafa [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); O' Neil, James [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Budinger, Thomas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2011-08-16

The goal of this project is to determine optimum conditions for bacterial oxidation of hydrocarbons and long-chain alkanes that are representative of petroleum contamination of the environment. Polycyclic Aromatic Hydrocarbons (PAHs) are of concern because of their toxicity, low volatility, and resistance to microbial degradation, especially under anaerobic conditions. The uniqueness of our approach is to use carbon-11 in lieu of the traditional use of carbon-14.

Behaviour of marine oil-degrading bacterial populations in a continuous culture system

Digital Repository Service at National Institute of Oceanography (India)

Mohandass, C.; David, J.J.; Nair, S.; LokaBharathi, P.A.; Chandramohan, D.

In pursuit of developing an oil-degrading microbial consortium, we used the principle of "plasmid assisted molecular breeding" (PAMB) in a continuous culture system. Three marine bacteria, Pseudomonas putida, Brevibacterium epidermidis...

Bioremediation of PAH-contamined soils: Consequences on formation and degradation of polar-polycyclic aromatic compounds and microbial community abundance.

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Biache, Coralie; Ouali, Salma; Cébron, Aurélie; Lorgeoux, Catherine; Colombano, Stéfan; Faure, Pierre

2017-05-05

A bioslurry batch experiment was carried out over five months on three polycyclic aromatic compound (PAC) contaminated soils to study the PAC (PAH and polar-PAC) behavior during soil incubation and to evaluate the impact of PAC contamination on the abundance of microbial communities and functional PAH-degrading populations. Organic matter characteristics and reactivity, assessed through solvent extractable organic matter and PAC contents, and soil organic matter mineralization were monitored during 5 months. Total bacteria and fungi, and PAH-ring hydroxylating dioxygenase genes were quantified. Results showed that PAHs and polar-PACs were degraded with different degradation dynamics. Differences in degradation rates were observed among the three soils depending on PAH distribution and availability. Overall, low molecular weight compounds were preferentially degraded. Degradation selectivity between isomers and structurally similar compounds was observed which could be used to check the efficiency of bioremediation processes. Bacterial communities were dominant over fungi and were most likely responsible for PAC degradation. Abundance of PAH-degrading bacteria increased during incubations, but their proportion in the bacterial communities tended to decrease. The accumulation of some oxygenated-PACs during the bioslurry experiment underlines the necessity to monitor these compounds during application of remediation treatment on PAH contaminated soils. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of newly isolated Pseudonocardia sp. N23 with high 1,4-dioxane-degrading ability.

Science.gov (United States)

Yamamoto, Norifumi; Saito, Yuji; Inoue, Daisuke; Sei, Kazunari; Ike, Michihiko

2018-01-02

This study was conducted to elucidate the 1,4-dioxane degradation characteristics of a newly isolated 1,4-dioxane-degrading bacterial strain and evaluate the applicability of the strain to biological 1,4-dioxane removal from wastewater. A bacterial strain (designated strain N23) capable of degrading 1,4-dioxane as the sole carbon and energy source was isolated from an enrichment culture prepared from 1,4-dioxane-contaminated groundwater. Strain N23 was phylogenetically identified as belonging to the genus Pseudonocardia, based on 16S rRNA gene sequencing. 1,4-Dioxane degradation experiments revealed that strain N23 is capable of constitutive 1,4-dioxane degradation. Further, this strain exhibited the highest specific 1,4-dioxane degradation rate of 0.230 mg-1,4-dioxane (mg-protein) -1  h -1 among 1,4-dioxane-degrading bacteria with constitutively expressed degrading enzymes reported to date. In addition, strain N23 was shown to degrade up to 1100 mg L -1 of 1,4-dioxane without significant inhibition, and to maintain a high level of 1,4-dioxane degradation activity under a wide pH (pH 3.8-8.2) and temperature (20-35 °C) range. In particular, the specific 1,4-dioxane degradation rate, even at pH 3.8, was 83% of the highest rate at pH 7.0. In addition, strain N23 was capable of utilizing ethylene glycol and diethylene glycol, which are both considered to be present in 1,4-dioxane-containing industrial wastewater, as the sole carbon source. The present results indicate that strain N23 exhibits the potential for 1,4-dioxane removal from industrial wastewater. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Isolation and identification of aerobic polychlorinated biphenyls degrading bacteria

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Bibi Fatemeh Nabavi

2013-01-01

Full Text Available Aims: The purpose of this study was to isolate and identify aerobic polychlorinated biphenyls (PCBs degrading bacteria. Materials and Methods: This study was performed in lab scale aerobic sequencing batch biofilm reactor. Polyurethane foams were used as bio-carrier and synthetic wastewater was prepared with PCBs in transformer oil as the main substrate (20-700 μg/l and acetone as a solvent for PCBs as well as microelements. After achieving to adequate microbial population and acclimation of microorganisms to PCB compounds with high efficiency of PCB removal, identification of degrading microbial species was performed by 16s rRNA gene sequencing of isolated bacteria. Results: Gene sequencing results of the isolated bacteria showed that Rhodococcus spp., Pseudomonas spp., Pseudoxanthomonas spp., Agromyces spp., and Brevibacillus spp. were dominant PCB-degrading bacteria. Conclusion: PCB compounds can be degraded by some microorganisms under aerobic or anaerobic conditions or at least be reduced to low chlorinated congeners, despite their chemical stability and toxicity. Based on the results of the study, five bacterial species capable of degrading PCBs in transformer oil have been identified.

Insight in the PCB-degrading functional community in long-term contaminated soil under bioremediation

Energy Technology Data Exchange (ETDEWEB)

Petric, Ines; Hrsak, Dubravka; Udikovic-Kolic, Nikolina [Ruder Boskovic Inst., Division for Marine and Environmental Research, Zagreb (Croatia); Fingler, Sanja [Inst. for Medical Research and Occupational Health, Zagreb (Croatia); Bru, David; Martin-Laurent, Fabrice [INRA, Univ. der Bourgogne, Soil and Environmental Microbiology, Dijon (France)

2011-02-15

A small-scale bioremediation assay was developed in order to get insight into the functioning of a polychlorinated biphenyl (PCB) degrading community during the time course of bioremediation treatment of a contaminated soil. The study was conducted with the aim to better understand the key mechanisms involved in PCB-removal from soils. Materials and methods Two bioremediation strategies were applied in the assay: (a) biostimulation (addition of carvone as inducer of biphenyl pathway, soya lecithin for improving PCB bioavailability, and xylose as supplemental carbon source) and (b) bioaugmentation with selected seed cultures TSZ7 or Rhodococcus sp. Z6 originating from the transformer station soil and showing substantial PCB-degrading activity. Functional PCB-degrading community was investigated by using molecular-based approaches (sequencing, qPCR) targeting bphA and bphC genes, coding key enzymes of the upper biphenyl pathway, in soil DNA extracts. In addition, kinetics of PCBs removal during the bioremediation treatment was determined using gas chromatography mass spectrometry analyses. Results and discussion bphA-based phylogeny revealed that bioremediation affected the structure of the PCB-degrading community in soils, with Rhodococcus-like bacterial populations developing as dominant members. Tracking of this population further indicated that applied bioremediation treatments led to its enrichment within the PCB-degrading community. The abundance of the PCB-degrading community, estimated by quantifying the copy number of bphA and bphC genes, revealed that it represented up to 0.3% of the total bacterial community. All bioremediation treatments were shown to enhance PCB reduction in soils, with approximately 40% of total PCBs being removed during a 1-year period. The faster PCB reduction achieved in bioaugmented soils suggested an important role of the seed cultures in bioremediation processes. Conclusions The PCBs degrading community was modified in response to

Molecular analysis of the bacterial diversity in a specialized consortium for diesel oil degradation

Energy Technology Data Exchange (ETDEWEB)

Paixao, Douglas Antonio Alvaredo; Accorsini, Fabio Raphael; Vidotti, Maria Benincasa; Lemos, Eliana Gertrudes de Macedo [Universidade Estadual Paulista (FCAV/UNESP), Jaboticabal, SP (Brazil). Fac. de Ciencias Agrarias e Veterinarias], Emails: douglas_unespfcav@yahoo.com.br, vidotti@netsite.com.bregerle@fcav.unesp.br; Dimitrov, Mauricio Rocha [Universidade de Sao Paulo (USP), SP (Brazil)], Email: mau_dimitrov@yahoo.com.br; Pereira, Rodrigo Matheus [EMBRAPARA Soybean - Empresa Brasileira de Pesquisa Agropecuaria (EMBRAPA - Soja), Londrina, PR (Brazil)], Email: poetbr@gmail.com

2010-05-15

Diesel oil is a compound derived from petroleum, consisting primarily of hydrocarbons. Poor conditions in transportation and storage of this product can contribute significantly to accidental spills causing serious ecological problems in soil and water and affecting the diversity of the microbial environment. The cloning and sequencing of the 16S rRNA gene is one of the molecular techniques that allows estimation and comparison of the microbial diversity in different environmental samples. The aim of this work was to estimate the diversity of microorganisms from the Bacteria domain in a consortium specialized in diesel oil degradation through partial sequencing of the 16S rRNA gene. After the extraction of DNA metagenomics, the material was amplified by PCR reaction using specific oligonucleotide primers for the 16S rRNA gene. The PCR products were cloned into a pGEM-T-Easy vector (Promega), and Escherichia coli was used as the host cell for recombinant DNAs. The partial clone sequencing was obtained using universal oligonucleotide primers from the vector. The genetic library obtained generated 431 clones. All the sequenced clones presented similarity to phylum Proteobacteria, with Gammaproteobacteria the most present group (49.8 % of the clones), followed by Alphaproteobacteira (44.8 %) and Betaproteobacteria (5.4 %). The Pseudomonas genus was the most abundant in the metagenomics library, followed by the Parvibaculum and the Sphingobium genus, respectively. After partial sequencing of the 16S rRNA, the diversity of the bacterial consortium was estimated using DOTUR software. When comparing these sequences to the database from the National Center for Biotechnology Information (NCBI), a strong correlation was found between the data generated by the software used and the data deposited in NCBI. (author)

Lignin degradation: microorganisms, enzymes involved, genomes analysis and evolution.

Science.gov (United States)

Janusz, Grzegorz; Pawlik, Anna; Sulej, Justyna; Swiderska-Burek, Urszula; Jarosz-Wilkolazka, Anna; Paszczynski, Andrzej

2017-11-01

Extensive research efforts have been dedicated to describing degradation of wood, which is a complex process; hence, microorganisms have evolved different enzymatic and non-enzymatic strategies to utilize this plentiful plant material. This review describes a number of fungal and bacterial organisms which have developed both competitive and mutualistic strategies for the decomposition of wood and to thrive in different ecological niches. Through the analysis of the enzymatic machinery engaged in wood degradation, it was possible to elucidate different strategies of wood decomposition which often depend on ecological niches inhabited by given organism. Moreover, a detailed description of low molecular weight compounds is presented, which gives these organisms not only an advantage in wood degradation processes, but seems rather to be a new evolutionatory alternative to enzymatic combustion. Through analysis of genomics and secretomic data, it was possible to underline the probable importance of certain wood-degrading enzymes produced by different fungal organisms, potentially giving them advantage in their ecological niches. The paper highlights different fungal strategies of wood degradation, which possibly correlates to the number of genes coding for secretory enzymes. Furthermore, investigation of the evolution of wood-degrading organisms has been described. © FEMS 2017.

A Phosphorylation Switch on Lon Protease Regulates Bacterial Type III Secretion System in Host

Directory of Open Access Journals (Sweden)

Xiaofeng Zhou

2018-01-01

Full Text Available Most pathogenic bacteria deliver virulence factors into host cytosol through type III secretion systems (T3SS to perturb host immune responses. The expression of T3SS is often repressed in rich medium but is specifically induced in the host environment. The molecular mechanisms underlying host-specific induction of T3SS expression is not completely understood. Here we demonstrate in Xanthomonas citri that host-induced phosphorylation of the ATP-dependent protease Lon stabilizes HrpG, the master regulator of T3SS, conferring bacterial virulence. Ser/Thr/Tyr phosphoproteome analysis revealed that phosphorylation of Lon at serine 654 occurs in the citrus host. In rich medium, Lon represses T3SS by degradation of HrpG via recognition of its N terminus. Genetic and biochemical data indicate that phosphorylation at serine 654 deactivates Lon proteolytic activity and attenuates HrpG proteolysis. Substitution of alanine for Lon serine 654 resulted in repression of T3SS gene expression in the citrus host through robust degradation of HrpG and reduced bacterial virulence. Our work reveals a novel mechanism for distinct regulation of bacterial T3SS in different environments. Additionally, our data provide new insight into the role of protein posttranslational modification in the regulation of bacterial virulence.

Mangrove microniches determine the structural and functional diversity of enriched petroleum hydrocarbon-degrading consortia.

Science.gov (United States)

Gomes, Newton C M; Flocco, Cecilia G; Costa, Rodrigo; Junca, Howard; Vilchez, Ramiro; Pieper, Dietmar H; Krögerrecklenfort, Ellen; Paranhos, Rodolfo; Mendonça-Hagler, Leda C S; Smalla, Kornelia

2010-11-01

In this study, the combination of culture enrichments and molecular tools was used to identify bacterial guilds, plasmids and functional genes potentially important in the process of petroleum hydrocarbon (PH) decontamination in mangrove microniches (rhizospheres and bulk sediment). In addition, we aimed to recover PH-degrading consortia (PHDC) for future use in remediation strategies. The PHDC were enriched with petroleum from rhizosphere and bulk sediment samples taken from a mangrove chronically polluted with oil hydrocarbons. Southern blot hybridization (SBH) assays of PCR amplicons from environmental DNA before enrichments resulted in weak positive signals for the functional gene types targeted, suggesting that PH-degrading genotypes and plasmids were in low abundance in the rhizosphere and bulk sediments. However, after enrichment, these genes were detected and strong microniche-dependent differences in the abundance and composition of hydrocarbonoclastic bacterial populations, plasmids (IncP-1α, IncP-1β, IncP-7 and IncP-9) and functional genes (naphthalene, extradiol and intradiol dioxygenases) were revealed by in-depth molecular analyses [PCR-denaturing gradient gel electrophoresis and hybridization (SBH and microarray)]. Our results suggest that, despite the low abundance of PH-degrading genes and plasmids in the environmental samples, the original bacterial composition of the mangrove microniches determined the structural and functional diversity of the PHDC enriched. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Anaerobic degradation of naphthalene by the mixed bacteria under nitrate reducing conditions

International Nuclear Information System (INIS)

Dou Junfeng; Liu Xiang; Ding Aizhong

2009-01-01

Mixed bacteria were enriched from soil samples contaminated with polycyclic aromatic hydrocarbons (PAHs). The anaerobic degradation characteristics by the enriched bacteria with different initial naphthalene concentrations were investigated under nitrate reducing conditions. The results showed that the mixed bacteria could degrade nearly all the naphthalene over the incubations of 25 days when the initial naphthalene concentration was below 30 mg/L. The degradation rates of naphthalene increased with increasing initial concentrations. A high naphthalene concentration of 30 mg/L did not inhibit neither on the bacterial growth nor on the naphthalene degradation ability. The accumulation of nitrite was occurred during the reduction of nitrate, and a nitrite concentration of 50 mg/L had no inhibition effect on the degradation of naphthalene. The calculation of electron balances revealed that most of the naphthalene was oxidized whereas a small proportion was used for cell synthesis.

Metagenomic identification of bacterioplankton taxa and pathways involved in microcystin degradation in lake erie.

Directory of Open Access Journals (Sweden)

Xiaozhen Mou

Full Text Available Cyanobacterial harmful blooms (CyanoHABs that produce microcystins are appearing in an increasing number of freshwater ecosystems worldwide, damaging quality of water for use by human and aquatic life. Heterotrophic bacteria assemblages are thought to be important in transforming and detoxifying microcystins in natural environments. However, little is known about their taxonomic composition or pathways involved in the process. To address this knowledge gap, we compared the metagenomes of Lake Erie free-living bacterioplankton assemblages in laboratory microcosms amended with microcystins relative to unamended controls. A diverse array of bacterial phyla were responsive to elevated supply of microcystins, including Acidobacteria, Actinobacteria, Bacteroidetes, Planctomycetes, Proteobacteria of the alpha, beta, gamma, delta and epsilon subdivisions and Verrucomicrobia. At more detailed taxonomic levels, Methylophilales (mainly in genus Methylotenera and Burkholderiales (mainly in genera Bordetella, Burkholderia, Cupriavidus, Polaromonas, Ralstonia, Polynucleobacter and Variovorax of Betaproteobacteria were suggested to be more important in microcystin degradation than Sphingomonadales of Alphaproteobacteria. The latter taxa were previously thought to be major microcystin degraders. Homologs to known microcystin-degrading genes (mlr were not overrepresented in microcystin-amended metagenomes, indicating that Lake Erie bacterioplankton might employ alternative genes and/or pathways in microcystin degradation. Genes for xenobiotic metabolism were overrepresented in microcystin-amended microcosms, suggesting they are important in bacterial degradation of microcystin, a phenomenon that has been identified previously only in eukaryotic systems.

Methanol removal efficiency and bacterial diversity of an activated carbon biofilter.

Science.gov (United States)

Babbitt, Callie W; Pacheco, Adriana; Lindner, Angela S

2009-12-01

Motivated by the need to establish an economical and environmentally friendly methanol control technology for the pulp and paper industry, a bench-scale activated carbon biofiltration system was developed. This system was evaluated for its performance in removing methanol from an artificially contaminated air stream and characterized for its bacterial diversity over time, under varied methanol loading rates, and in different spatial regions of the filter. The biofilter system, composed of a novel packing mixture, provided an excellent support for growth and activity of methanol-degrading bacteria, resulting in approximately 100% methanol removal efficiency for loading rates of 1-17 g/m(3) packing/h, when operated both with and without inoculum containing enriched methanol-degrading bacteria. Although bacterial diversity and abundance varied over the length of the biofilter, the populations present rapidly formed a stable community that was maintained over the entire 138-day operation of the system and through variable operating conditions, as observed by PCR-DGGE methods that targeted all bacteria as well as specific methanol-oxidizing microorganisms. Phylogenetic analysis of bands excised and sequenced from DGGE gels indicated that the biofilter system supported a diverse community of methanol-degrading bacteria, with high similarity to species in the genera Methylophilus (beta-proteobacteria), Hyphomicrobium and Methylocella (both alpha-proteobacteria).

From Rare to Dominant: a Fine-Tuned Soil Bacterial Bloom during Petroleum Hydrocarbon Bioremediation.

Science.gov (United States)

Fuentes, Sebastián; Barra, Bárbara; Caporaso, J Gregory; Seeger, Michael

2016-02-01

Hydrocarbons are worldwide-distributed pollutants that disturb various ecosystems. The aim of this study was to characterize the short-lapse dynamics of soil microbial communities in response to hydrocarbon pollution and different bioremediation treatments. Replicate diesel-spiked soil microcosms were inoculated with either a defined bacterial consortium or a hydrocarbonoclastic bacterial enrichment and incubated for 12 weeks. The microbial community dynamics was followed weekly in microcosms using Illumina 16S rRNA gene sequencing. Both the bacterial consortium and enrichment enhanced hydrocarbon degradation in diesel-polluted soils. A pronounced and rapid bloom of a native gammaproteobacterium was observed in all diesel-polluted soils. A unique operational taxonomic unit (OTU) related to the Alkanindiges genus represented ∼ 0.1% of the sequences in the original community but surprisingly reached >60% after 6 weeks. Despite this Alkanindiges-related bloom, inoculated strains were maintained in the community and may explain the differences in hydrocarbon degradation. This study shows the detailed dynamics of a soil bacterial bloom in response to hydrocarbon pollution, resembling microbial blooms observed in marine environments. Rare community members presumably act as a reservoir of ecological functions in high-diversity environments, such as soils. This rare-to-dominant bacterial shift illustrates the potential role of a rare biosphere facing drastic environmental disturbances. Additionally, it supports the concept of "conditionally rare taxa," in which rareness is a temporary state conditioned by environmental constraints. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Microbial diversity and anaerobic hydrocarbon degradation potential in an oil-contaminated mangrove sediment.

Science.gov (United States)

Andrade, Luiza L; Leite, Deborah C A; Ferreira, Edir M; Ferreira, Lívia Q; Paula, Geraldo R; Maguire, Michael J; Hubert, Casey R J; Peixoto, Raquel S; Domingues, Regina M C P; Rosado, Alexandre S

2012-08-30

Mangrove forests are coastal wetlands that provide vital ecosystem services and serve as barriers against natural disasters like tsunamis, hurricanes and tropical storms. Mangroves harbour a large diversity of organisms, including microorganisms with important roles in nutrient cycling and availability. Due to tidal influence, mangroves are sites where crude oil from spills farther away can accumulate. The relationship between mangrove bacterial diversity and oil degradation in mangrove sediments remains poorly understood. Mangrove sediment was sampled from 0-5, 15-20 and 35-40 cm depth intervals from the Suruí River mangrove (Rio de Janeiro, Brazil), which has a history of oil contamination. DGGE fingerprinting for bamA, dsr and 16S rRNA encoding fragment genes, and qPCR analysis using dsr and 16S rRNA gene fragment revealed differences with sediment depth. Analysis of bacterial 16S rRNA gene diversity revealed changes with depth. DGGE for bamA and dsr genes shows that the anaerobic hydrocarbon-degrading community profile also changed between 5 and 15 cm depth, and is similar in the two deeper sediments, indicating that below 15 cm the anaerobic hydrocarbon-degrading community appears to be well established and homogeneous in this mangrove sediment. qPCR analysis revealed differences with sediment depth, with general bacterial abundance in the top layer (0-5 cm) being greater than in both deeper sediment layers (15-20 and 35-40 cm), which were similar to each other.

Evaluation of friction produced by self-ligating, conventional and Barbosa Versatile brackets

Directory of Open Access Journals (Sweden)

Jurandir Antonio BARBOSA

Full Text Available Abstract Introduction The Barbosa Versatile bracket design may provide lower frictional force and greater sliding. However, no in vitro studies have shown its sliding mechanisms and frictional resistance, particularly in comparison with other self-ligating or conventional brackets. Objective To compare the frictional resistance among self-ligating brackets (EasyClip/ Aditek, Damon MX/ Ormco and In Ovation R/ GAC; conventional brackets (Balance Roth/ GAC, and Roth Monobloc/ Morelli; and Barbosa Versatile bracket (Barbosa Versatile/ GAC with different angles and arch wires. Material and method Brackets were tested with the 0.014", 0.018", 0.019"×0.025" and 0.021"×0.025" stainless steel wires, with 0, 5, 10, 15 and 20 degree angulations. Tying was performed with elastomeric ligature for conventional and Barbosa Versatile brackets, or with a built-in clip system of the self-ligating brackets. A universal testing machine was used to obtain sliding strength and friction value readouts between brackets and wires. Result Three-way factorial ANOVA 4×5×6 (brackets × angulation × wire and Tukey tests showed statistically significant differences for all factors and all interactions (p<0.0001. Static frictional resistance showed a lower rate for Barbosa Versatile bracket and higher rates for Roth Monobloc and Balance brackets. Conclusion The lowest frictional resistance was obtained with the Barbosa Versatile bracket and self-ligating brackets in comparison with the conventional type. Increasing the diameter of the wires increased the frictional resistance. Smaller angles produced less frictional resistance.

Isolation of imidacloprid degrading bacteria from cotton fields

International Nuclear Information System (INIS)

Shahid, M.N.; Jabeen, F.; Hassan, S.W.

2008-01-01

Imidacloprid is cyclodiene organochlorine, used as an insecticide all over the world an possess a serious environmental threat. It is mostly used for cotton insects (bollworm, aphid and white fly). For isolation of imidacloprid degrading bacteria three soil samples were collected from cotton fields of district Layyah having five years history of use. Soil samples were analyzed by measuring pH and electric conductivity. The isolation of imidacroprid degrading bacteria was performed by enrichment technique. Fourteen bacterial strains: S/sub i-a/, S/sub i-b/, S/sub i-c/, S/sub i-d/, S/sub i-e/, S/sub a-a/, S/a-b/, S/a-c/, S/a-d/, S/sub b-a/, S/sub b-b/, S/sub b-c/, S/sub b-d/ and S/b-e/ were isolated on the basis of their colony morphologies. The purified colonies were characterized morphologically physiologically and biochemically. Gram staining was done and Gram staining was done and Gram negative strains were confirmed on macConkey agar and Eosin methylene blue. Bacterial strains were also checked for different minimal media in which only carbon source was the imidacloprid. For this purpose FTW, FTW without N/sun 2/, NSM, M/sub 9/ and MM/sub 2/ media were used and their optical densities were taken on spectrophotometer, isolates were checked for resistance to antibiotics and heavy metals. On the basis of these characteristics. S/sub a-c/ and S/sub l-d/ were assigned to Enterobacteriaceae, S/sub a-b/ to Pseudomonadaceae and rest of the bacterial isolates were affiliated. (author)

Isolation of Methylophaga spp. from Marine Dimethylsulfide-Degrading Enrichment Cultures and Identification of Polypeptides Induced during Growth on Dimethylsulfide▿

OpenAIRE

Schäfer, Hendrik

2007-01-01

Dimethylsulfide (DMS)-degrading enrichment cultures were established from samples of coastal seawater, nonaxenic Emiliania huxleyi cultures, and mixed marine methyl halide-degrading enrichment cultures. Bacterial populations from a broad phylogenetic range were identified in the mixed DMS-degrading enrichment cultures by denaturing gradient gel electrophoresis (DGGE). Sequences of dominant DGGE bands were similar to those of members of the genera Methylophaga and Alcanivorax. Several closely ...

The Bacterial Microflora of Fish, Revised

Directory of Open Access Journals (Sweden)

B. Austin

2006-01-01

Full Text Available The results of numerous studies indicate that fish possess bacterial populations on or in their skin, gills, digestive tract, and light-emitting organs. In addition, the internal organs (kidney, liver, and spleen of healthy fish may contain bacteria, but there is debate about whether or not muscle is actually sterile. Using traditional culture-dependent techniques, the numbers and taxonomic composition of the bacterial populations generally reflect those of the surrounding water. More modern culture-independent approaches have permitted the recognition of previously uncultured bacteria. The role of the organisms includes the ability to degrade complex molecules (therefore exercising a potential benefit in nutrition, to produce vitamins and polymers, and to be responsible for the emission of light by the light-emitting organs of deep-sea fish. Taxa, including Pseudomonas, may contribute to spoilage by the production of histamines in fish tissue.

Allochthonous bioaugmentation in ex situ treatment of crude oil-polluted sediments in the presence of an effective degrading indigenous microbiome

KAUST Repository

Fodelianakis, Stylianos

2015-04-01

Oil-polluted sediment bioremediation depends on both physicochemical and biological parameters, but the effect of the latter cannot be evaluated without the optimization of the former. We aimed in optimizing the physicochemical parameters related to biodegradation by applying an ex-situ landfarming set-up combined with biostimulation to oil-polluted sediment, in order to determine the added effect of bioaugmentation by four allochthonous oil-degrading bacterial consortia in relation to the degradation efficiency of the indigenous community. We monitored hydrocarbon degradation, sediment ecotoxicity and hydrolytic activity, bacterial population sizes and bacterial community dynamics, characterizing the dominant taxa through time and at each treatment. We observed no significant differences in total degradation, but increased ecotoxicity between the different treatments receiving both biostimulation and bioaugmentation and the biostimulated-only control. Moreover, the added allochthonous bacteria quickly perished and were rarely detected, their addition inducing minimal shifts in community structure although it altered the distribution of the residual hydrocarbons in two treatments. Therefore, we concluded that biodegradation was mostly performed by the autochthonous populations while bioaugmentation, in contrast to biostimulation, did not enhance the remediation process. Our results indicate that when environmental conditions are optimized, the indigenous microbiome at a polluted site will likely outperform any allochthonous consortium.

Hydrocarbon degraders establish at the costs of microbial richness, abundance and keystone taxa after crude oil contamination in permafrost environments

Science.gov (United States)

Yang, Sizhong; Wen, Xi; Shi, Yulan; Liebner, Susanne; Jin, Huijun; Perfumo, Amedea

2016-01-01

Oil spills from pipeline ruptures are a major source of terrestrial petroleum pollution in cold regions. However, our knowledge of the bacterial response to crude oil contamination in cold regions remains to be further expanded, especially in terms of community shifts and potential development of hydrocarbon degraders. In this study we investigated changes of microbial diversity, population size and keystone taxa in permafrost soils at four different sites along the China-Russia crude oil pipeline prior to and after perturbation with crude oil. We found that crude oil caused a decrease of cell numbers together with a reduction of the species richness and shifts in the dominant phylotypes, while bacterial community diversity was highly site-specific after exposure to crude oil, reflecting different environmental conditions. Keystone taxa that strongly co-occurred were found to form networks based on trophic interactions, that is co-metabolism regarding degradation of hydrocarbons (in contaminated samples) or syntrophic carbon cycling (in uncontaminated samples). With this study we demonstrate that after severe crude oil contamination a rapid establishment of endemic hydrocarbon degrading communities takes place under favorable temperature conditions. Therefore, both endemism and trophic correlations of bacterial degraders need to be considered in order to develop effective cleanup strategies. PMID:27886221

Characterization of bacterial consortia capable of degrading 4-chlorobenzoate and 4-bromobenzoate under denitrifying conditions.

Science.gov (United States)

Song, Bongkeun; Kerkhof, Lee J; Häggblom, Max M

2002-08-06

4-Chlorobenzoate and 4-bromobenzoate were readily degraded in denitrifying enrichment cultures established with river sediment, estuarine sediment or agricultural soil as inoculum. Stable denitrifying consortia were obtained and maintained by serial dilution and repeated feeding of substrates. Microbial community analyses were performed to characterize the 4-chlorobenzoate and 4-bromobenzoate degrading consortia with terminal restriction fragment length polymorphism (T-RFLP) and cloning of 16S rRNA genes from the cultures. Interestingly, two major terminal restriction fragments (T-RFs) in the 4-chlorobenzoate degrading consortia and one T-RF in the 4-bromobenzoate utilizing consortium were observed from T-RFLP analysis regardless of their geographical and ecological origins. The two T-RFs (clones 4CB1 and 4CB2) in 4-chlorobenzoate degrading consortia were identified as members of the beta-subunit of the Proteobacteria on the basis of 16S rRNA sequencing analysis. Phylogenetic analysis of 16S rRNA genes showed that clone 4CB1 was closely related to Thauera aromatica while clone 4CB2 was distantly related to the genera Limnobacter and Ralstonia. The 4-bromobenzoate utilizing consortium mainly consisted of one T-RF, which was identical to clone 4CB2 in spite of different enrichment substrate. This suggests that degradation of 4-chlorobenzoate and 4-bromobenzoate under denitrifying conditions was mediated by bacteria belonging to the beta-subunit of the Proteobacteria.

Transformation of pWWO in Rhizobium leguminosarum DPT to Engineer Toluene Degrading Ability for Rhizoremediation

OpenAIRE

Goel, Garima; Pandey, Piyush; Sood, Anchal; Bisht, Sandeep; Maheshwari, D. K.; Sharma, G. D.

2011-01-01

Rhizoremediation of organic xenobiotics is based on interactions between plants and their associated micro-organisms. The present work was designed to engineer a bacterial system having toluene degradation ability along with plant growth promoting characteristics for effective rhizoremediation. pWWO harboring the genes responsible for toluene breakdown was isolated from Pseudomonas putida MTCC 979 and successfully transformed in Rhizobium DPT. This resulted in a bacterial strain (DPTT) which ...

Isolation and characterization of mesotrione-degrading Bacillus sp. from soil

International Nuclear Information System (INIS)

Batisson, Isabelle; Crouzet, Olivier; Besse-Hoggan, Pascale; Sancelme, Martine; Mangot, Jean-Francois; Mallet, Clarisse; Bohatier, Jacques

2009-01-01

Dissipation kinetics of mesotrione, a new triketone herbicide, sprayed on soil from Limagne (Puy-de-Dome, France) showed that the soil microflora were able to biotransform it. Bacteria from this soil were cultured in mineral salt solution supplemented with mesotrione as sole source of carbon for the isolation of mesotrione-degrading bacteria. The bacterial community structure of the enrichment cultures was analyzed by temporal temperature gradient gel electrophoresis (TTGE). The TTGE fingerprints revealed that mesotrione had an impact on bacterial community structure only at its highest concentrations and showed mesotrione-sensitive and mesotrione-adapted strains. Two adapted strains, identified as Bacillus sp. and Arthrobacter sp., were isolated by colony hybridization methods. Biodegradation assays showed that only the Bacillus sp. strain was able to completely and rapidly biotransform mesotrione. Among several metabolites formed, 2-amino-4-methylsulfonylbenzoic acid (AMBA) accumulated in the medium. Although sulcotrione has a chemical structure closely resembling that of mesotrione, the isolates were unable to degrade it. - A Bacillus sp. strain isolated from soil was able to completely and rapidly biotransform the triketone herbicide mesotrione

Bacterial Degradation of Nitrogenous Energetic Compounds (NEC) in Coastal Waters and Sediments

Science.gov (United States)

2008-09-10

isotope values in the upper bay; C) DOC appears to be high in lignin concentration, especially in the Patuxent River. Figure 12. Bacterial...polycyclic aromatic hydrocarbons (PAHs, lignin ; Suen et al. 1996). We hypothesized that nitrogenous energetics will be transient in nitrogen-limited...water, TNT nitro groups can be reduced to amines (Barrows et al. 1996) affecting its reactivity (Achtnich et al. 2000). The presence of reduced

Glycogen with short average chain length enhances bacterial durability

Science.gov (United States)

Wang, Liang; Wise, Michael J.

2011-09-01

Glycogen is conventionally viewed as an energy reserve that can be rapidly mobilized for ATP production in higher organisms. However, several studies have noted that glycogen with short average chain length in some bacteria is degraded very slowly. In addition, slow utilization of glycogen is correlated with bacterial viability, that is, the slower the glycogen breakdown rate, the longer the bacterial survival time in the external environment under starvation conditions. We call that a durable energy storage mechanism (DESM). In this review, evidence from microbiology, biochemistry, and molecular biology will be assembled to support the hypothesis of glycogen as a durable energy storage compound. One method for testing the DESM hypothesis is proposed.

Biodegradation in a Partially Saturated Sand Matrix: Compounding Effects of Water Content, Bacterial Spatial Distribution, and Motility

DEFF Research Database (Denmark)

Dechesne, Arnaud; Owsianiak, Mikolaj; Bazire, Alexis

2010-01-01

colonizing these zones or on pollutant mass transfer to neighboring zones containing degraders. In a model system, we quantified the role exerted by water on mineralization rate in the context of a heterogeneously distributed degradation potential. Alginate beads colonized by Pseudomonas putida KT2440 were......Bacterial pesticide degraders are generally heterogeneously distributed in soils, leaving soil volumes devoid of degradation potential. This is expected to have an impact on degradation rates because the degradation of pollutant molecules in such zones will be contingent either on degraders...... inserted at prescribed locations in sand microcosms so that the initial spatial distribution of the mineralization potential was controlled. The mineralization rate was strongly affected by the matric potential (decreasing rate with decreasing matric potential) and by the initial distribution...

Isolation of Bacterial Strain for Biodegradation of Fats, Oil and Grease

International Nuclear Information System (INIS)

Alkhatib, M.F.; Mohd Zahangir Alam; Shabana, H.F.M.

2015-01-01

Fat, oil and grease (FOG) deposition is one of the major problems that harm the environment and cause dissatisfaction for human. Uncontrolled and un-pre-treated FOG removal from the kitchen could lead to its accumulation in the piping system. Problems include the interference of fat with the aerobic microorganisms that are responsible in treating the wastewater by reducing oxygen transfer rates and for anaerobic microorganisms; their efficiency could also be reduced due to the reduction of the transport of soluble substrates to the bacterial biomass. Biodegradation could be one of the effective means to treat FOG. The main objective of this study is to isolate bacterial strains from the FOG waste and identify the strains that are capable in biodegrading FOG waste. FOG sample was collected from a sewer manhole. Enrichment technique was applied, followed by isolation of bacterial strains to determine which strain is able to degrade the FOG deposition. Some morphology for the bacterial strain was done to determine its characteristics. (author)

Nest Material Shapes Eggs Bacterial Environment.

Directory of Open Access Journals (Sweden)

Cristina Ruiz-Castellano

Full Text Available Selective pressures imposed by pathogenic microorganisms to embryos have selected in hosts for a battery of antimicrobial lines of defenses that includes physical and chemical barriers. Due to the antimicrobial properties of volatile compounds of green plants and of chemicals of feather degrading bacteria, the use of aromatic plants and feathers for nest building has been suggested as one of these barriers. However, experimental evidence suggesting such effects is scarce in the literature. During two consecutive years, we explored experimentally the effects of these nest materials on loads of different groups of bacteria (mesophilic bacteria, Enterobacteriaceae, Staphylococcus and Enterococcus of eggshells in nests of spotless starlings (Sturnus unicolor at the beginning and at the end of the incubation period. This was also explored in artificial nests without incubation activity. We also experimentally increased bacterial density of eggs in natural and artificial nests and explored the effects of nest lining treatments on eggshell bacterial load. Support for the hypothetical antimicrobial function of nest materials was mainly detected for the year and location with larger average values of eggshell bacterial density. The beneficial effects of feathers and plants were more easily detected in artificial nests with no incubation activity, suggesting an active role of incubation against bacterial colonization of eggshells. Pigmented and unpigmented feathers reduced eggshell bacterial load in starling nests and artificial nest boxes. Results from artificial nests allowed us to discuss and discard alternative scenarios explaining the detected association, particularly those related to the possible sexual role of feathers and aromatic plants in starling nests. All these results considered together confirm the antimicrobial functionality mainly of feathers but also of plants used as nest materials, and highlight the importance of temporally and

Nest Material Shapes Eggs Bacterial Environment.

Science.gov (United States)

Ruiz-Castellano, Cristina; Tomás, Gustavo; Ruiz-Rodríguez, Magdalena; Martín-Gálvez, David; Soler, Juan José

2016-01-01

Selective pressures imposed by pathogenic microorganisms to embryos have selected in hosts for a battery of antimicrobial lines of defenses that includes physical and chemical barriers. Due to the antimicrobial properties of volatile compounds of green plants and of chemicals of feather degrading bacteria, the use of aromatic plants and feathers for nest building has been suggested as one of these barriers. However, experimental evidence suggesting such effects is scarce in the literature. During two consecutive years, we explored experimentally the effects of these nest materials on loads of different groups of bacteria (mesophilic bacteria, Enterobacteriaceae, Staphylococcus and Enterococcus) of eggshells in nests of spotless starlings (Sturnus unicolor) at the beginning and at the end of the incubation period. This was also explored in artificial nests without incubation activity. We also experimentally increased bacterial density of eggs in natural and artificial nests and explored the effects of nest lining treatments on eggshell bacterial load. Support for the hypothetical antimicrobial function of nest materials was mainly detected for the year and location with larger average values of eggshell bacterial density. The beneficial effects of feathers and plants were more easily detected in artificial nests with no incubation activity, suggesting an active role of incubation against bacterial colonization of eggshells. Pigmented and unpigmented feathers reduced eggshell bacterial load in starling nests and artificial nest boxes. Results from artificial nests allowed us to discuss and discard alternative scenarios explaining the detected association, particularly those related to the possible sexual role of feathers and aromatic plants in starling nests. All these results considered together confirm the antimicrobial functionality mainly of feathers but also of plants used as nest materials, and highlight the importance of temporally and geographically

Bacterial Community Structure Shifted by Geosmin in Granular Activated Carbon System of Water Treatment Plants.

Science.gov (United States)

Pham, Ngoc Dung; Lee, Eun-Hee; Chae, Seon-Ha; Cho, Yongdeok; Shin, Hyejin; Son, Ahjeong

2016-01-01

We investigated the relation between the presence of geosmin in water and the bacterial community structure within the granular activated carbon (GAC) system of water treatment plants in South Korea. GAC samples were collected in May and August of 2014 at three water treatment plants (Sungnam, Koyang, and Yeoncho in Korea). Dissolved organic carbon and geosmin were analyzed before and after GAC treatment. Geosmin was found in raw water from Sungnam and Koyang water treatment plants but not in that from Yeoncho water treatment plant. Interestingly, but not surprisingly, the 16S rRNA clone library indicated that the bacterial communities from the Sungnam and Koyang GAC systems were closely related to geosmin-degrading bacteria. Based on the phylogenetic tree and multidimensional scaling plot, bacterial clones from GAC under the influence of geosmin were clustered with Variovorax paradoxus strain DB 9b and Comamonas sp. DB mg. In other words, the presence of geosmin in water might have inevitably contributed to the growth of geosmin degraders within the respective GAC system.

Transformation of pWWO in Rhizobium leguminosarum DPT to Engineer Toluene Degrading Ability for Rhizoremediation.

Science.gov (United States)

Goel, Garima; Pandey, Piyush; Sood, Anchal; Bisht, Sandeep; Maheshwari, D K; Sharma, G D

2012-06-01

Rhizoremediation of organic xenobiotics is based on interactions between plants and their associated micro-organisms. The present work was designed to engineer a bacterial system having toluene degradation ability along with plant growth promoting characteristics for effective rhizoremediation. pWWO harboring the genes responsible for toluene breakdown was isolated from Pseudomonas putida MTCC 979 and successfully transformed in Rhizobium DPT. This resulted in a bacterial strain (DPT(T)) which had the ability to degrade toluene as well as enhance growth of host plant. The frequency of transformation was recorded 5.7 × 10(-6). DPT produced IAA, siderophore, chitinase, HCN, ACC deaminase, solubilized inorganic phosphate, fixed atmospheric nitrogen and inhibited the growth of Fusarium oxysporum and Macrophomina phaseolina in vitro. During pot assay, 50 ppm toluene in soil was found to inhibit the germination of Cajanus cajan seeds. However when the seeds bacterized with toluene degrading P. putida or R. leguminosarum DPT were sown in pots, again no germination was observed. Non-bacterized as well as bacterized seeds germinated successfully in toluene free soil as control. The results forced for an alternative mode of application of bacteria for rhizoremediation purpose. Hence bacterial suspension was mixed with soil having 50 ppm of toluene. Germination index in DPT treated soil was 100% while in P. putida it was 50%. Untreated soil with toluene restricted the seeds to germinate.

Effect of trichloroethylene on the competitive behavior of toluene-degrading bacteria

NARCIS (Netherlands)

Mars, Astrid E.; Prins, Gjalt T.; Wietzes, Pieter; Koning, Wim de; Janssen, Dick B.

The influence of trichloroethylene (TCE) on a mixed culture of four different toluene-degrading bacterial strains (Pseudomonas putida mt-2, P. putida F1, P. putida GJ31, and Burkholderia cepacia G4) was studied with a fed-batch culture. The strains were competing for toluene, which was added at a

'Rare biosphere' bacteria as key phenanthrene degraders in coastal seawaters.

Science.gov (United States)

Sauret, Caroline; Séverin, Tatiana; Vétion, Gilles; Guigue, Catherine; Goutx, Madeleine; Pujo-Pay, Mireille; Conan, Pascal; Fagervold, Sonja K; Ghiglione, Jean-François

2014-11-01

By coupling DNA-SIP and pyrosequencing approaches, we identified Cycloclasticus sp. as a keystone degrader of polycyclic aromatic hydrocarbons (PAH) despite being a member of the 'rare biosphere' in NW Mediterranean seawaters. We discovered novel PAH-degrading bacteria (Oceanibaculum sp., Sneathiella sp.) and we identified other groups already known to possess this function (Alteromonas sp., Paracoccus sp.). Together with Cycloclasticus sp., these groups contributed to potential in situ phenanthrene degradation at a rate >0.5 mg l(-1) day(-1), sufficient to account for a considerable part of PAH degradation. Further, we characterized the PAH-tolerant bacterial communities, which were much more diverse in the polluted site by comparison to unpolluted marine references. PAH-tolerant bacteria were also members of the rare biosphere, such as Glaciecola sp. Collectively, these data show the complex interactions between PAH-degraders and PAH-tolerant bacteria and provide new insights for the understanding of the functional ecology of marine bacteria in polluted waters. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biodegradation of ethyl acetate in radioactive liquid organic waste by bacterial communities

International Nuclear Information System (INIS)

Ferreira, Rafael V.P.; Sakata, Solange K.; Borba, Tania R.; Bellini, Maria H.; Marumo, Julio T.; Dutra, Fernando

2009-01-01

The research and development program in reprocessing of low burn-up spent fuel elements began in Brazil in 70's, originating the lab -scale hot cell, known as CELESTE located at IPEN-CNEN/SP. The program was ended at the beginning of 90's and part of the radioactive waste generated mainly from the analytical laboratories is stored at the Waste Management Laboratory. Among various types of radioactive waste generated, the organic liquid represents a major problem for its management, because it can not be directly solidified with cement. The objective of this work is to develop a pretreatment methodology to degrade the ethyl acetate present in organic liquid waste so that it can subsequently be immobilized in cement. This work was divided into two parts: selection and adaptation of three bacterial communities for growth in medium containing ethyl acetate and degradation experiments of ethyl acetate present in radioactive organic liquid waste. The results showed that from bacterial communities the highest biodegradation level observed was 77%. (author)

Monitoring of Gasoline-ethanol Degradation In Undisturbed Soil

Science.gov (United States)

Österreicher-Cunha, P.; Nunes, C. M. F.; Vargas, E. A.; Guimarães, J. R. D.; Costa, A.

Environmental contamination problems are greatly emphasised nowadays because of the direct threat they represent for human health. Traditional remediation methods fre- quently present low efficiency and high costs; therefore, biological treatment is being considered as an accessible and efficient alternative for soil and water remediation. Bioventing, commonly used to remediate petroleum hydrocarbon spills, stimulates the degradation capacity of indigenous microorganisms by providing better subsur- face oxygenation. In Brazil, gasoline and ethanol are mixed (78:22 v/v); some authors indicate that despite gasoline high degradability, its degradation in subsurface is hin- dered by the presence of much more rapidly degrading ethanol. Contaminant distribu- tion and degradation in the subsurface can be monitored by several physical, chemical and microbiological methodologies. This study aims to evaluate and follow the degra- dation of a gasoline-ethanol mixture in a residual undisturbed tropical soil from Rio de Janeiro. Bioventing was used to enhance microbial degradation. Shifts in bacte- rial culturable populations due to contamination and treatment effects were followed by conventional microbiology methods. Ground Penetrating Radar (GPR) measure- ments, which consist of the emission of electro-magnetic waves into the soil, yield a visualisation of contaminant degradation because of changes in soil conductivity due to microbial action on the pollutants. Chemical analyses will measure contaminant residue in soil. Our results disclosed contamination impact as well as bioventing stim- ulation on soil culturable heterotrophic bacterial populations. This multidisciplinary approach allows for a wider evaluation of processes occurring in soil.

Effect of feeding tannin degrading bacterial culture (Streptococcus gallolyticus strain TDGB 406) on nutrient utilization, urinary purine derivatives and growth performance of goats fed on Quercus semicarpifolia leaves.

Science.gov (United States)

Kumar, K; Chaudhary, L C; Agarwal, N; Kamra, D N

2014-10-01

To study the effect of supplementation of tannin degrading bacterial culture (Streptococcus gallolyticus strain TDGB 406) on growth performance, nutrient utilization and urinary purine derivatives of goats fed on oak (Quercus semicarpifolia) leaves. For growth study, eighteen billy goats (4 month old, average body weight 9.50 ± 1.50 kg) were distributed into three groups of six animals each. The animals of group 1 served as control while animals of groups 2 (T1) and 3 (T2) were given (@ 5 ml/kg live weight) autoclaved and live culture of isolate TDGB 406 (10(6) cells/ml) respectively. The animals were fed measured quantity of dry oak leaves as the main roughage source and ad libitum maize hay along with fixed quantity of concentrate mixture. The feeding of live culture of isolate TDGB 406 (probiotic) did not affect dry matter intake and digestibility of nutrients except that of dry matter and crude protein, which was higher in T2 group as compared to control. All the animals were in positive nitrogen balance. There was no significant effect of feeding isolate TDGB 406 on urinary purine derivatives (microbial protein production) in goats. The body weight gain and average live weight gain was significantly higher (p = 0.071) in T2 group as compared to control. Feed conversion efficiency was also better in the goats fed on live culture of TDGB 406 (T2). The feeding of tannin degrading bacterial isolate TDGB 406 as probiotic resulted in improved growth performance and feed conversion ratio in goats fed on oak leaves as one of the main roughage source. Journal of Animal Physiology and Animal Nutrition © 2013 Blackwell Verlag GmbH.

Nanobiocatalytic Degradation of Acid Orange 7

Science.gov (United States)

Hastings, Jason

The catalytic properties of various metal nanoparticles have led to their use in environmental remediation applications. However, these remediation strategies are limited by their ability to deliver catalytic nanoparticles and a suitable electron donor to large treatment zones. Clostridium pasteurianum BC1 cells, loaded with bio-Pd nanoparticles, were used to effectively catalyze the reductive degradation and removal of Acid Orange 7 (AO7), a model azo compound. Hydrogen produced fermentatively by the C. pasteurianum BC1 acted as the electron donor for the process. Pd-free bacterial cultures or control experiments conducted with heat-killed cells showed limited reduction of AO7. Experiments also showed that the in situ biological production of H2 by C. pasteurianum BC1 was essential for the degradation of AO7, which suggests a novel process where the in situ microbial production of hydrogen is directly coupled to the catalytic bio-Pd mediated reduction of AO7. The differences in initial degradation rate for experiments conducted using catalyst concentrations of 1ppm Pd and 5ppm Pd and an azo dye concentration of 100ppm AO7 was 0.39 /hr and 1.94 /hr respectively, demonstrating the importance of higher concentrations of active Pd(0). The degradation of AO7 was quick as demonstrated by complete reductive degradation of 50ppm AO7 in 2 hours in experiments conducted using a catalyst concentration of 5ppm Pd. Dye degradation products were analyzed via Gas Chromatograph-Mass Spectrometer (GCMS), High Performance Liquid Chromatography (HPLC), UltraViolet-Visible spectrophotometer (UV-Vis) and Matrix-Assisted Laser Desorption/Ionization (MALDI) spectrometry. The presence of 1-amino 2-naphthol, one of the hypothesized degradation products, was confirmed using mass spectrometry.

Biogenic amines degradation by microorganisms isolated from cheese

Directory of Open Access Journals (Sweden)

Irena Butor

2017-01-01

Full Text Available The aim of this study was the isolation and characterization of microorganisms able to degrade biogenic amines and their identification. Individual microorganisms were obtained by isolation from commercially available foodstuffs and food produced in the technological laboratories of Faculty of Technology, Tomas Bata University in Zlín and subsequently identified by MALDI-TOF MS. The results of MALDI-TOF MS identification were verified by 16S rRNA sequenation. In this work was studied the ability of 5 bacterial strains positive to biogenic amines degradation isolated from dairy products to decrease biogenic amines content in vitro and quantified reduction in the concentration of biogenic amines tryptamine, β-phenylethylamine, putrescine, cadaverine, histamine and tyramine. The level of degradation (decrease of biogenic amines was determined on the base of the ability to grow in media with biogenic amines as the sole source carbon and nitrogen. The isolated strains with the ability of degradation of one or more biogenic amines were cultured in medium supplemented with relevant biogenic amines, the media derivatized with dansyl chloride and these amines separated by HPLC at a wavelength of 254 nm. From five tested strains identified as Bacillus subtilis, Bacillus pumilus, Enterobacter cloacae, Rhizobium radiobacter and Acinetobacter pitii, isolated from gouda type cheese, the greatest ability of degradation was observed in Bacillus subtilis, which was capable to degrade almost all amount of histamine, cadaverine and putrescine. Other four strains showed a lower rate of degradation than Bacillus subtilis, but the ability to degrade biogenic amines with these microorganisms was still significant.

Microbial degradation of waste hydrocarbons in oily sludge from some Romanian oil fields

International Nuclear Information System (INIS)

Lazar, I.; Dobrota, S.; Voicu, A.; Stefanescu, M.; Sandulescu, L.; Petrisor, I.G.

1999-01-01

During oil production and processing activities, significant quantities of oily sludge are produced. The sludge represents not only an environmental pollution source but also occupies big spaces in storage tanks. Romania, an experienced European oil-producing and processing country, is faced with environmental problems generated by oily sludge accumulations. Many such accumulations are to be submitted to bioremediation processes based on the hydrocarbon degradation activity of naturally occurring, selectively isolated bacteria. In this paper the results concerning a laboratory screening of several natural bacterial consortia and laboratory tests to establish the performance in degradation of hydrocarbons contained in oily sludges from Otesti oil field area, are presented. As a result of the laboratory screening, we selected six natural bacterial consortia (BCSl-I 1 to BCSl-I 6 ) with high ability in degradation of hydrocarbons from paraffinic and non-paraffinic asphaltic oils (between 25.53%-64.30% for non-paraffinic asphaltic oil and between 50.25%-72.97% for paraffinic oil). The laboratory tests proved that microbial degradation of hydrocarbons contained in oily sludge from Otesti oil field area varied from 16.75% to 95.85% in moving conditions (Erlenmeyers of 750 ml on rotary shaker at 200 rpm) and from 16.85% to 51.85% in static conditions (Petri dishes Oe 10 cm or vessels of 500 ml)

Idiosyncratic Genome Degradation in a Bacterial Endosymbiont of Periodical Cicadas.

Science.gov (United States)

Campbell, Matthew A; Łukasik, Piotr; Simon, Chris; McCutcheon, John P

2017-11-20

When a free-living bacterium transitions to a host-beneficial endosymbiotic lifestyle, it almost invariably loses a large fraction of its genome [1, 2]. The resulting small genomes often become stable in size, structure, and coding capacity [3-5], as exemplified by Sulcia muelleri, a nutritional endosymbiont of cicadas. Sulcia's partner endosymbiont, Hodgkinia cicadicola, similarly remains co-linear in some cicadas diverged by millions of years [6, 7]. But in the long-lived periodical cicada Magicicada tredecim, the Hodgkinia genome has split into dozens of tiny, gene-sparse circles that sometimes reside in distinct Hodgkinia cells [8]. Previous data suggested that all other Magicicada species harbor complex Hodgkinia populations, but the timing, number of origins, and outcomes of the splitting process were unknown. Here, by sequencing Hodgkinia metagenomes from the remaining six Magicicada and two sister species, we show that each Magicicada species harbors Hodgkinia populations of at least 20 genomic circles. We find little synteny among the 256 Hodgkinia circles analyzed except between the most closely related cicada species. Gene phylogenies show multiple Hodgkinia lineages in the common ancestor of Magicicada and its closest known relatives but that most splitting has occurred within Magicicada and has given rise to highly variable Hodgkinia gene dosages among species. These data show that Hodgkinia genome degradation has proceeded down different paths in different Magicicada species and support a model of genomic degradation that is stochastic in outcome and nonadaptive for the host. These patterns mirror the genomic instability seen in some mitochondria. Copyright © 2017 Elsevier Ltd. All rights reserved.

Distribution, origin and transformation of amino sugars sand bacterial contribution to estuarine particulate organic matter

Digital Repository Service at National Institute of Oceanography (India)

Khodse, V.B.; Bhosle, N.B.

transformation and greater bacterial contribution to POM during the former season. Degradation trends observed with TPAS were well supported by those obtained with carbohydrates andaminoacids. Based on Murconcent rations,bacteria accounted for 24% to 35...

Benzo[4,5]cyclohepta[1,2-b]fluorene: an isomeric motif for pentacene containing linearly fused five-, six- and seven-membered rings

KAUST Repository

Yang, Xuejin

2016-06-07

Benzo[4,5]cyclohepta[1,2-b]fluorene (5a), a new π-conjugated polycyclic hydrocarbon containing linearly fused six-, five-, six-, seven- and six-membered rings (C6-C5-C6-C7-C6), was designed and its stable derivatives 5b and 5c were synthesized. With 22 π electrons, 5a is an isomer of pentacene with quinoidal, dipolar ionic and diradical resonance forms. Molecules 5b and 5c were experimentally investigated with cyclic voltammetry, electronic absorption spectroscopy and X-ray crystallographic analysis, and theoretically studied by calculating the NICS value, diradical character and dipole moment. A comparison of 5a–c with pentacene and other pentacene analogues containing linearly fused five- or seven- membered rings was also conducted and discussed. It was found that 5b behaved as a p-type organic semiconductor in solution-processed thin film transistors with field effect mobility of up to 0.025 cm2/Vs.

Benzo[4,5]cyclohepta[1,2-b]fluorene: an isomeric motif for pentacene containing linearly fused five-, six- and seven-membered rings

KAUST Repository

Yang, Xuejin; Shi, Xueliang; Aratani, Naoki; Goncalves, Theo; Huang, Kuo-Wei; Yamada, Hiroko; Chi, Chunyan; Miao, Qian

2016-01-01

Benzo[4,5]cyclohepta[1,2-b]fluorene (5a), a new π-conjugated polycyclic hydrocarbon containing linearly fused six-, five-, six-, seven- and six-membered rings (C6-C5-C6-C7-C6), was designed and its stable derivatives 5b and 5c were synthesized. With 22 π electrons, 5a is an isomer of pentacene with quinoidal, dipolar ionic and diradical resonance forms. Molecules 5b and 5c were experimentally investigated with cyclic voltammetry, electronic absorption spectroscopy and X-ray crystallographic analysis, and theoretically studied by calculating the NICS value, diradical character and dipole moment. A comparison of 5a–c with pentacene and other pentacene analogues containing linearly fused five- or seven- membered rings was also conducted and discussed. It was found that 5b behaved as a p-type organic semiconductor in solution-processed thin film transistors with field effect mobility of up to 0.025 cm2/Vs.

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.

A Novel Platform for Evaluating the Environmental Impacts on Bacterial Cellulose Production.

Science.gov (United States)

Basu, Anindya; Vadanan, Sundaravadanam Vishnu; Lim, Sierin

2018-04-10

Bacterial cellulose (BC) is a biocompatible material with versatile applications. However, its large-scale production is challenged by the limited biological knowledge of the bacteria. The advent of synthetic biology has lead the way to the development of BC producing microbes as a novel chassis. Hence, investigation on optimal growth conditions for BC production and understanding of the fundamental biological processes are imperative. In this study, we report a novel analytical platform that can be used for studying the biology and optimizing growth conditions of cellulose producing bacteria. The platform is based on surface growth pattern of the organism and allows us to confirm that cellulose fibrils produced by the bacteria play a pivotal role towards their chemotaxis. The platform efficiently determines the impacts of different growth conditions on cellulose production and is translatable to static culture conditions. The analytical platform provides a means for fundamental biological studies of bacteria chemotaxis as well as systematic approach towards rational design and development of scalable bioprocessing strategies for industrial production of bacterial cellulose.

Microbial degradation of dissolved proteins in seawater

International Nuclear Information System (INIS)

Hollibaugh, J.T.; Azam, F.

1983-01-01

An experimental protocol using radiolabeled proteins was developed to investigate the rates and mechanisms whereby dissolved proteins are degraded in natural marine plankton communities. The results of field observations and laboratory experiments indicate that proteins are degraded by a particle-bound, thermolabile system, presumably bacteria-associated enzymes, with an apparent half-saturation constant of ca. 25 μg bovine serum albumin (BSA) per liter. Gel permeation chromatography indicated that peptides of chain length intermediate between BSA and the final products of degradation (MW<700) do not accumulate in the medium. Competition experiments indicate that the system is relatively nonspecific. Turnover rates for the protein pool in samples collected in the Southern California Bight were of the same order of magnitude as the turnover rate of the L-leucine pool and were correlated with primary productivity, chlorophyll a concentrations, bacterial abundance and biomass, and L-leucine turnover rate. These data suggest that amino acids derived from proteins are utilized preferentially and do not completely mix with the amino acids in the bulk phase

Bioavailability of hydrocarbons to bacterial consortia during Triton X-100 mediated biodegradation in aqueous media.

Science.gov (United States)

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

2013-01-01

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

The Prestige oil spill: bacterial community dynamics during a field biostimulation assay

Energy Technology Data Exchange (ETDEWEB)

Jimenez, N; Solanas, A M [Barcelona Univ. (Spain). Dept. of Microbiology; Vinas, M [GIRO Technological Centre, Mollet del Valles (Spain); Bayona, J M; Albaiges, J [IIQAB-CSIC, Barcelona (Spain). Dept. of Environmental Chemistry

2007-12-15

A field bioremediation assay using the oleophilic fertilizer S200 was carried out 12 months after the Prestige heavy fuel-oil spill on a beach on the Cantabrian coast (north Spain). This assay showed that S200-enhanced oil degradation, particularly of high-molecular-weight n-alkanes and alkylated PAHs, suggesting an increase in the microbial bioavailability of these compounds. The bacterial community structure was determined by cultivation-independent analysis of polymerase chain reaction-amplified 16S rDNA by denaturing gradient gel electrophoresis. Bacterial community was mainly composed of {alpha}-Proteobacteria (Rhodobacteriaceae and Sphingomonadaceae). Representatives of {gamma}-Proteobacteria (Chromatiales, Moraxellaceae, and Halomonadaceae), Bacteroidetes (Flavobacteriaceae), and Actinobacteria group (Nocardiaceae and Corynebacteriaceae) were also found. The addition of the fertilizer led to the appearance of the bacterium Mesonia algae in the early stages, with a narrow range of growth substrates, which has been associated with the common alga Achrosiphonia sonderi. The presence of Mesonia algae may be attributable to the response of the microbial community to the addition of N and P rather than indicating a role in the biodegradation process. The Rhodococcus group appeared in both assay plots, especially at the end of the experiment. It was also found at another site on the Galician coast that had been affected by the same spill. This genus has been associated with the degradation of n-alkanes up to C{sub 36}. Taking into account the high content of heavy alkanes in the Prestige fuel, these microorganisms could play a significant role in the degradation of such fuel. A similar bacterial community structure was observed at another site that showed a similar degree of fuel weathering. (orig.)

Imidazolide monolayers for versatile reactive microcontact printing

NARCIS (Netherlands)

Hsu, S.H.; Reinhoudt, David; Huskens, Jurriaan; Velders, Aldrik

2008-01-01

Imidazolide monolayers prepared from the reaction of amino SAMs with N,N-carbonyldiimidazole (CDI) are used as a versatile platform for surface patterning with amino-, carboxyl- and alcohol-containing compounds through reactive microcontact printing (µCP). To demonstrate the surface reactivity of

Isolation and identification of a bacterium from marine shrimp digestive tract: A new degrader of starch and protein

Science.gov (United States)

Li, Jiqiu; Tan, Beiping; Mai, Kangsen

2011-09-01

It is a practical approach to select candidate probiotic bacterial stains on the basis of their special traits. Production of digestive enzyme was used as a trait to select a candidate probiotic bacterial strain in this study. In order to select a bacterium with the ability to degrade both starch and protein, an ideal bacterial strain STE was isolated from marine shrimp ( Litopenaeus vannamei) intestines by using multiple selective media. The selected isolate STE was identified on the basis of its morphological, physiological, and biochemical characteristics as well as molecular analyses. Results of degradation experiments confirmed the ability of the selected isolate to degrade both starch and casein. The isolate STE was aerobic, Gram-negative, rod-shaped, motile and non-spore-forming, and had catalase and oxidase activities but no glucose fermentation activity. Among the tested carbon/nitrogen sources, only Tween40, alanyl-glycine, aspartyl-glycine, and glycyl-l-glutamic acid were utilized by the isolate STE. Results of homology comparison analyses of the 16S rDNA sequences showed that the isolate STE had a high similarity to several Pseudoalteromonas species and, in the phylogenetic tree, grouped with P. ruthenica with maximum bootstrap support (100%). In conclusion, the isolate STE was characterized as a novel strain belonging to the genus Pseudoalteromonas. This study provides a further example of a probiotic bacterial strain with specific characteristics isolated from the host gastrointestinal tract.

Bacterial proteasome activator bpa (rv3780) is a novel ring-shaped interactor of the mycobacterial proteasome.

Science.gov (United States)

Delley, Cyrille L; Laederach, Juerg; Ziemski, Michal; Bolten, Marcel; Boehringer, Daniel; Weber-Ban, Eilika

2014-01-01

The occurrence of the proteasome in bacteria is limited to the phylum of actinobacteria, where it is maintained in parallel to the usual bacterial compartmentalizing proteases. The role it plays in these organisms is still not fully understood, but in the human pathogen Mycobacterium tuberculosis (Mtb) the proteasome supports persistence in the host. In complex with the ring-shaped ATPase Mpa (called ARC in other actinobacteria), the proteasome can degrade proteins that have been post-translationally modified with the prokaryotic ubiquitin-like protein Pup. Unlike for the eukaryotic proteasome core particle, no other bacterial proteasome interactors have been identified to date. Here we describe and characterize a novel bacterial proteasome activator of Mycobacterium tuberculosis we termed Bpa (Rv3780), using a combination of biochemical and biophysical methods. Bpa features a canonical C-terminal proteasome interaction motif referred to as the HbYX motif, and its orthologs are only found in those actinobacteria encoding the proteasomal subunits. Bpa can inhibit degradation of Pup-tagged substrates in vitro by competing with Mpa for association with the proteasome. Using negative-stain electron microscopy, we show that Bpa forms a ring-shaped homooligomer that can bind coaxially to the face of the proteasome cylinder. Interestingly, Bpa can stimulate the proteasomal degradation of the model substrate β-casein, which suggests it could play a role in the removal of non-native or damaged proteins.

Microbial diversity and anaerobic hydrocarbon degradation potential in an oil-contaminated mangrove sediment

Directory of Open Access Journals (Sweden)

Andrade Luiza L

2012-08-01

Full Text Available Abstract Background Mangrove forests are coastal wetlands that provide vital ecosystem services and serve as barriers against natural disasters like tsunamis, hurricanes and tropical storms. Mangroves harbour a large diversity of organisms, including microorganisms with important roles in nutrient cycling and availability. Due to tidal influence, mangroves are sites where crude oil from spills farther away can accumulate. The relationship between mangrove bacterial diversity and oil degradation in mangrove sediments remains poorly understood. Results Mangrove sediment was sampled from 0–5, 15–20 and 35–40 cm depth intervals from the Suruí River mangrove (Rio de Janeiro, Brazil, which has a history of oil contamination. DGGE fingerprinting for bamA, dsr and 16S rRNA encoding fragment genes, and qPCR analysis using dsr and 16S rRNA gene fragment revealed differences with sediment depth. Conclusions Analysis of bacterial 16S rRNA gene diversity revealed changes with depth. DGGE for bamA and dsr genes shows that the anaerobic hydrocarbon-degrading community profile also changed between 5 and 15 cm depth, and is similar in the two deeper sediments, indicating that below 15 cm the anaerobic hydrocarbon-degrading community appears to be well established and homogeneous in this mangrove sediment. qPCR analysis revealed differences with sediment depth, with general bacterial abundance in the top layer (0–5 cm being greater than in both deeper sediment layers (15–20 and 35–40 cm, which were similar to each other.

Quantitative proteomic analyses of the microbial degradation of estrone under various background nitrogen and carbon conditions.

Science.gov (United States)

Du, Zhe; Chen, Yinguang; Li, Xu

2017-10-15

Microbial degradation of estrogenic compounds can be affected by the nitrogen source and background carbon in the environment. However, the underlying mechanisms are not well understood. The objective of this study was to elucidate the molecular mechanisms of estrone (E1) biodegradation at the protein level under various background nitrogen (nitrate or ammonium) and carbon conditions (no background carbon, acetic acid, or humic acid as background carbon) by a newly isolated bacterial strain. The E1 degrading bacterial strain, Hydrogenophaga atypica ZD1, was isolated from river sediments and its proteome was characterized under various experimental conditions using quantitative proteomics. Results show that the E1 degradation rate was faster when ammonium was used as the nitrogen source than with nitrate. The degradation rate was also faster when either acetic acid or humic acid was present in the background. Proteomics analyses suggested that the E1 biodegradation products enter the tyrosine metabolism pathway. Compared to nitrate, ammonium likely promoted E1 degradation by increasing the activities of the branched-chain-amino-acid aminotransferase (IlvE) and enzymes involved in the glutamine synthetase-glutamine oxoglutarate aminotransferase (GS-GOGAT) pathway. The increased E1 degradation rate with acetic acid or humic acid in the background can also be attributed to the up-regulation of IlvE. Results from this study can help predict and explain E1 biodegradation kinetics under various environmental conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecular Mechanisms of Enhanced Bacterial Growth on Hexadecane with Red Clay.

Science.gov (United States)

Jung, Jaejoon; Jang, In-Ae; Ahn, Sungeun; Shin, Bora; Kim, Jisun; Park, Chulwoo; Jee, Seung Cheol; Sung, Jung-Suk; Park, Woojun

2015-11-01

Red clay was previously used to enhance bioremediation of diesel-contaminated soil. It was speculated that the enhanced degradation of diesel was due to increased bacterial growth. In this study, we selected Acinetobacter oleivorans DR1, a soil-borne degrader of diesel and alkanes, as a model bacterium and performed transcriptional analysis using RNA sequencing to investigate the cellular response during hexadecane utilization and the mechanism by which red clay promotes hexadecane degradation. We confirmed that red clay promotes the growth of A. oleivorans DR1 on hexadecane, a major component of diesel, as a sole carbon source. Addition of red clay to hexadecane-utilizing DR1 cells highly upregulated β-oxidation, while genes related to alkane oxidation were highly expressed with and without red clay. Red clay also upregulated genes related to oxidative stress defense, such as superoxide dismutase, catalase, and glutaredoxin genes, suggesting that red clay supports the response of DR1 cells to oxidative stress generated during hexadecane utilization. Increased membrane fluidity in the presence of red clay was confirmed by fatty acid methyl ester analysis at different growth phases, suggesting that enhanced growth on hexadecane could be due to increased uptake of hexadecane coupled with upregulation of downstream metabolism and oxidative stress defense. The monitoring of the bacterial community in soil with red clay for a year revealed that red clay stabilized the community structure.

Fungal Laccases Degradation of Endocrine Disrupting Compounds

Directory of Open Access Journals (Sweden)

Gemma Macellaro

2014-01-01

Full Text Available Over the past decades, water pollution by trace organic compounds (ng/L has become one of the key environmental issues in developed countries. This is the case of the emerging contaminants called endocrine disrupting compounds (EDCs. EDCs are a new class of environmental pollutants able to mimic or antagonize the effects of endogenous hormones, and are recently drawing scientific and public attention. Their widespread presence in the environment solicits the need of their removal from the contaminated sites. One promising approach to face this challenge consists in the use of enzymatic systems able to react with these molecules. Among the possible enzymes, oxidative enzymes are attracting increasing attention because of their versatility, the possibility to produce them on large scale, and to modify their properties. In this study five different EDCs were treated with four different fungal laccases, also in the presence of both synthetic and natural mediators. Mediators significantly increased the efficiency of the enzymatic treatment, promoting the degradation of substrates recalcitrant to laccase oxidation. The laccase showing the best performances was chosen to further investigate its oxidative capabilities against micropollutant mixtures. Improvement of enzyme performances in nonylphenol degradation rate was achieved through immobilization on glass beads.

Intracellular drug delivery nanocarriers of glutathione-responsive degradable block copolymers having pendant disulfide linkages.

Science.gov (United States)

Khorsand, Behnoush; Lapointe, Gabriel; Brett, Christopher; Oh, Jung Kwon

2013-06-10

Self-assembled micelles of amphiphilic block copolymers (ABPs) with stimuli-responsive degradation (SRD) properties have a great promise as nanotherapeutics exhibiting enhanced release of encapsulated therapeutics into targeted cells. Here, thiol-responsive degradable micelles based on a new ABP consisting of a pendant disulfide-labeled methacrylate polymer block (PHMssEt) and a hydrophilic poly(ethylene oxide) (PEO) block were investigated as effective intracellular nanocarriers of anticancer drugs. In response to glutathione (GSH) as a cellular trigger, the cleavage of pendant disulfide linkages in hydrophobic PHMssEt blocks of micellar cores caused the destabilization of self-assembled micelles due to change in hydrophobic/hydrophilic balance. Such GSH-triggered micellar destabilization changed their size distribution with an appearance of large aggregates and led to enhanced release of encapsulated anticancer drugs. Cell culture results from flow cytometry and confocal laser scanning microscopy for cellular uptake as well as cell viability measurements for high anticancer efficacy suggest that new GSH-responsive degradable PEO-b-PHMssEt micelles offer versatility in multifunctional drug delivery applications.

Degradation of N-heterocyclic indole by a novel endophytic fungus Phomopsis liquidambari.

Science.gov (United States)

Chen, Yan; Xie, Xing-Guang; Ren, Cheng-Gang; Dai, Chuan-Chao

2013-02-01

A broad-spectrum endophytic Phomopsis liquidambari, was used to degrade environmental pollutant indole. In the condition of using indole as sole carbon and nitrogen source, the optimum concentration of indole supplied was determined to be 100 mg L(-1), with 41.7% ratio of indole degradation within 120 h. Exogenous addition of plant litter significantly increased indole degradation to 99.1% within 60 h. Indole oxidation to oxindole and isatin were the key steps limiting indole degradation. Plant litter addition induced fungus to produce laccase and LiP to non-specific oxidize indole. The results of fungal metabolites pathway through HPLC-MS and NMR analysis showed that indole was firstly oxidized to oxindole and isatin, and deoxidated to indolenie-2-dione, then hydroxylated to 2-dioxindole, which pyridine ring were cleaved through C-N position and changed to 2-aminobenzoic acid. Such metabolic pathway was similar with bacterial degradation of indole-3-acetic acid in plant. Copyright © 2012 Elsevier Ltd. All rights reserved.