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Alhajeri NS, Tawfik A, Elsamadony M, Al-Fadhli FM, Meng F. Synergistic algal/bacterial interaction in membrane bioreactor for detoxification of 1,2-dichloroethane-rich petroleum wastewater. J Hazard Mater 2024; 470:134125. [PMID: 38565016 DOI: 10.1016/j.jhazmat.2024.134125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/12/2024] [Accepted: 03/23/2024] [Indexed: 04/04/2024]
Abstract
The study addressed the challenge of treating petroleum industry wastewater with high concentrations of 1,2-dichloroethane (1,2-DCA) ranging from 384 to 1654 mg/L, which poses a challenge for bacterial biodegradation and algal photodegradation. To overcome this, a collaborative approach using membrane bioreactors (MBRs) that combine algae and bacteria was employed. This synergistic method effectively mitigated the toxicity of 1,2-DCA and curbed MBR fouling. Two types of MBRs were tested: one (B-MBR) used bacterial cultures and the other (AB-MBR) incorporated a mix of algal and bacterial cultures. The AB-MBR significantly contributed to 1,2-DCA removal, with algae accounting for over 20% and bacteria for approximately 49.5% of the dechlorination process. 1,2-DCA metabolites, including 2-chloroethanol, 2-chloro-acetaldehyde, 2-chloroacetic acid, and acetic acid, were partially consumed as carbon sources by algae. Operational efficiency peaked at a 12-hour hydraulic retention time (HRT) in AB-MBR, enhancing enzyme activities crucial for 1,2-DCA degradation such as dehydrogenase (DH), alcohol dehydrogenase (ADH), and acetaldehyde dehydrogenase (ALDH). The microbial diversity in AB-MBR surpassed that in B-MBR, with a notable increase in Proteobacteria, Bacteroidota, Planctomycetota, and Verrucomicrobiota. Furthermore, AB-MBR showed a significant rise in the dominance of 1,2-DCA-degrading genus such as Pseudomonas and Acinetobacter. Additionally, algal-degrading phyla (e.g., Nematoda, Rotifera, and Streptophyta) were more prevalent in AB-MBR, substantially reducing the issue of membrane fouling.
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Affiliation(s)
- Nawaf S Alhajeri
- Department of Environmental Sciences, College of Life Sciences, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait.
| | - Ahmed Tawfik
- Department of Environmental Sciences, College of Life Sciences, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait
| | - Mohamed Elsamadony
- Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia; Interdisciplinary Research Center for Refining & Advanced Chemicals, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
| | - Fahad M Al-Fadhli
- Department of Chemical Engineering, College of Engineering and Petroleum, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait
| | - Fangang Meng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510006, China
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Peng P, Schneidewind U, Haest PJ, Bosma TNP, Danko AS, Smidt H, Atashgahi S. Reductive dechlorination of 1,2-dichloroethane in the presence of chloroethenes and 1,2-dichloropropane as co-contaminants. Appl Microbiol Biotechnol 2019; 103:6837-6849. [PMID: 31250061 PMCID: PMC6667407 DOI: 10.1007/s00253-019-09985-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 12/11/2022]
Abstract
1,2-Dichloroethane (1,2-DCA) is one of the most abundant manmade chlorinated organic contaminants in the world. Reductive dechlorination of 1,2-DCA by organohalide-respiring bacteria (OHRB) can be impacted by other chlorinated contaminants such as chloroethenes and chloropropanes that can co-exist with 1,2-DCA at contaminated sites. The aim of this study was to evaluate the effect of chloroethenes and 1,2-dichloropropane (1,2-DCP) on 1,2-DCA dechlorination using sediment cultures enriched with 1,2-DCA as the sole chlorinated compound (EA culture) or with 1,2-DCA and tetrachloroethene (PCE) (EB culture), and to model dechlorination kinetics. Both cultures contained Dehalococcoides as most predominated OHRB, and Dehalogenimonas and Geobacter as other known OHRB. In sediment-free enrichments obtained from the EA and EB cultures, dechlorination of 1,2-DCA was inhibited in the presence of the same concentrations of either PCE, vinyl chloride (VC), or 1,2-DCP; however, concurrent dechlorination of dual chlorinated compounds was achieved. In contrast, 1,2-DCA dechlorination completely ceased in the presence of cis-dichloroethene (cDCE) and only occurred after cDCE was fully dechlorinated. In turn, 1,2-DCA did not affect dechlorination of PCE, cDCE, VC, and 1,2-DCP. In sediment-free enrichments obtained from the EA culture, Dehalogenimonas 16S rRNA gene copy numbers decreased 1–3 orders of magnitude likely due to an inhibitory effect of chloroethenes. Dechlorination with and without competitive inhibition fit Michaelis-Menten kinetics and confirmed the inhibitory effect of chloroethenes and 1,2-DCP on 1,2-DCA dechlorination. This study reinforces that the type of chlorinated substrate drives the selection of specific OHRB, and indicates that removal of chloroethenes and in particular cDCE might be necessary before effective removal of 1,2-DCA at sites contaminated with mixed chlorinated solvents.
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Affiliation(s)
- Peng Peng
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Uwe Schneidewind
- Department of Civil and Environmental Engineering, Western University, London, ON, Canada
| | - Pieter Jan Haest
- Advanced Groundwater Techniques (AGT), Aartselaar, Belgium
- Division of Geology, Department of Earth and Environmental Sciences, KU Leuven, Heverlee, Belgium
| | - Tom N P Bosma
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Anthony S Danko
- Centre for Natural Resources and the Environment (CERENA), Department of Mining Engineering, University of Porto (FEUP), Porto, Portugal
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Siavash Atashgahi
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.
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Kokkonen P, Bednar D, Dockalova V, Prokop Z, Damborsky J. Conformational changes allow processing of bulky substrates by a haloalkane dehalogenase with a small and buried active site. J Biol Chem 2018; 293:11505-11512. [PMID: 29858243 PMCID: PMC6065182 DOI: 10.1074/jbc.ra117.000328] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 05/28/2018] [Indexed: 12/21/2022] Open
Abstract
Haloalkane dehalogenases catalyze the hydrolysis of halogen-carbon bonds in organic halogenated compounds and as such are of great utility as biocatalysts. The crystal structures of the haloalkane dehalogenase DhlA from the bacterium from Xanthobacter autotrophicus GJ10, specifically adapted for the conversion of the small 1,2-dichloroethane (DCE) molecule, display the smallest catalytic site (110 Å3) within this enzyme family. However, during a substrate-specificity screening, we noted that DhlA can catalyze the conversion of far bulkier substrates, such as the 4-(bromomethyl)-6,7-dimethoxy-coumarin (220 Å3). This large substrate cannot bind to DhlA without conformational alterations. These conformational changes have been previously inferred from kinetic analysis, but their structural basis has not been understood. Using molecular dynamic simulations, we demonstrate here the intrinsic flexibility of part of the cap domain that allows DhlA to accommodate bulky substrates. The simulations displayed two routes for transport of substrates to the active site, one of which requires the conformational change and is likely the route for bulky substrates. These results provide insights into the structure-dynamics function relationships in enzymes with deeply buried active sites. Moreover, understanding the structural basis for the molecular adaptation of DhlA to 1,2-dichloroethane introduced into the biosphere during the industrial revolution provides a valuable lesson in enzyme design by nature.
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Affiliation(s)
- Piia Kokkonen
- Loschmidt Laboratories, Department of Experimental Biology, Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; International Centre for Clinical Research, St. Anne's University Hospital, Pekarska 53, 656 91 Brno, Czech Republic
| | - David Bednar
- Loschmidt Laboratories, Department of Experimental Biology, Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; International Centre for Clinical Research, St. Anne's University Hospital, Pekarska 53, 656 91 Brno, Czech Republic
| | - Veronika Dockalova
- Loschmidt Laboratories, Department of Experimental Biology, Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; International Centre for Clinical Research, St. Anne's University Hospital, Pekarska 53, 656 91 Brno, Czech Republic
| | - Zbynek Prokop
- Loschmidt Laboratories, Department of Experimental Biology, Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; International Centre for Clinical Research, St. Anne's University Hospital, Pekarska 53, 656 91 Brno, Czech Republic.
| | - Jiri Damborsky
- Loschmidt Laboratories, Department of Experimental Biology, Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; International Centre for Clinical Research, St. Anne's University Hospital, Pekarska 53, 656 91 Brno, Czech Republic.
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Weatherill JJ, Atashgahi S, Schneidewind U, Krause S, Ullah S, Cassidy N, Rivett MO. Natural attenuation of chlorinated ethenes in hyporheic zones: A review of key biogeochemical processes and in-situ transformation potential. Water Res 2018; 128:362-382. [PMID: 29126033 DOI: 10.1016/j.watres.2017.10.059] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 10/12/2017] [Accepted: 10/28/2017] [Indexed: 06/07/2023]
Abstract
Chlorinated ethenes (CEs) are legacy contaminants whose chemical footprint is expected to persist in aquifers around the world for many decades to come. These organohalides have been reported in river systems with concerning prevalence and are thought to be significant chemical stressors in urban water ecosystems. The aquifer-river interface (known as the hyporheic zone) is a critical pathway for CE discharge to surface water bodies in groundwater baseflow. This pore water system may represent a natural bioreactor where anoxic and oxic biotransformation process act in synergy to reduce or even eliminate contaminant fluxes to surface water. Here, we critically review current process understanding of anaerobic CE respiration in the competitive framework of hyporheic zone biogeochemical cycling fuelled by in-situ fermentation of natural organic matter. We conceptualise anoxic-oxic interface development for metabolic and co-metabolic mineralisation by a range of aerobic bacteria with a focus on vinyl chloride degradation pathways. The superimposition of microbial metabolic processes occurring in sediment biofilms and bulk solute transport delivering reactants produces a scale dependence in contaminant transformation rates. Process interpretation is often confounded by the natural geological heterogeneity typical of most riverbed environments. We discuss insights from recent field experience of CE plumes discharging to surface water and present a range of practical monitoring technologies which address this inherent complexity at different spatial scales. Future research must address key dynamics which link supply of limiting reactants, residence times and microbial ecophysiology to better understand the natural attenuation capacity of hyporheic systems.
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Affiliation(s)
| | - Siavash Atashgahi
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Uwe Schneidewind
- Department of Engineering Geology and Hydrogeology, RWTH Aachen University, Aachen, Germany
| | - Stefan Krause
- School of Geography, Earth and Environmental Science, University of Birmingham, UK
| | - Sami Ullah
- School of Geography, Earth and Environmental Science, University of Birmingham, UK
| | | | - Michael O Rivett
- Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, UK; GroundH(2)O Plus Ltd., Quinton, Birmingham, UK
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5
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Nobre RCM, Nobre MMM, Campos TMP, Ogles D. In-situ biodegradation potential of 1,2-DCA and VC at sites with different hydrogeological settings. J Hazard Mater 2017; 340:417-426. [PMID: 28743073 DOI: 10.1016/j.jhazmat.2017.07.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/12/2017] [Accepted: 07/13/2017] [Indexed: 06/07/2023]
Abstract
This paper investigates the feasibility of applying in-situ Bioremediation (ISB) to three sites contaminated with vinyl chloride and/or chlorinated alkanes such as 1,2-DCA and 1,1,2-TCA, presenting distinct hydrogeological settings and history of contaminant loading. Biotransformation of these compounds is well established in laboratory studies and pure cultures. Due to confidential aspects, however, few field data are available to support real case studies to the predictability of their fate and lifetime in soil and groundwater. Bio-Trap® In Situ Microcosm (ISM) studies were performed in selected monitoring wells, and consisted of a control unit which simulated Monitored Natural Attenuation conditions and other units which were amended with either lactate, emulsified vegetable oil (EVO) or molasses as electron donors. For wells with moderate Dhc counts, the ISM study demonstrated that electron donor addition could stimulate further growth of Dhc and enhance reductive dechlorination. Conversely, for wells with high population counts, substrate addition did not alter results significantly. Site-specific determining factors that most influenced the biodegradation results were microbial activity, soil texture and presence of organic matter, site pH, redox conditions and presence of free phase.
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Affiliation(s)
- R C M Nobre
- Universidade Federal de Alagoas, IGDEMA/UFAL, BR-104, Maceio, AL, Brazil.
| | - M M M Nobre
- Universidade Federal de Alagoas, IGDEMA/UFAL, BR-104, Maceio, AL, Brazil.
| | - T M P Campos
- Pontifícia Universidade Católica do Rio de Janeiro, PUC-Rio, Brazil.
| | - D Ogles
- Microbial Insights, Knoxville, TN, USA.
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Palau J, Shouakar-Stash O, Hatijah Mortan S, Yu R, Rosell M, Marco-Urrea E, Freedman DL, Aravena R, Soler A, Hunkeler D. Hydrogen Isotope Fractionation during the Biodegradation of 1,2-Dichloroethane: Potential for Pathway Identification Using a Multi-element (C, Cl, and H) Isotope Approach. Environ Sci Technol 2017; 51:10526-10535. [PMID: 28810730 DOI: 10.1021/acs.est.7b02906] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Even though multi-element isotope fractionation patterns provide crucial information with which to identify contaminant degradation pathways in the field, those involving hydrogen are still lacking for many halogenated groundwater contaminants and degradation pathways. This study investigates for the first time hydrogen isotope fractionation during both aerobic and anaerobic biodegradation of 1,2-dichloroethane (1,2-DCA) using five microbial cultures. Transformation-associated isotope fractionation values (εbulkH) were -115 ± 18‰ (aerobic C-H bond oxidation), -34 ± 4‰ and -38 ± 4‰ (aerobic C-Cl bond cleavage via hydrolytic dehalogenation), and -57 ± 3‰ and -77 ± 9‰ (anaerobic C-Cl bond cleavage via reductive dihaloelimination). The dual-element C-H isotope approach (ΛC-H = Δδ2H/Δδ13C ≈ εbulkH/εbulkC, where Δδ2H and Δδ13C are changes in isotope ratios during degradation) resulted in clearly different ΛC-H values: 28 ± 4 (oxidation), 0.7 ± 0.1 and 0.9 ± 0.1 (hydrolytic dehalogenation), and 1.76 ± 0.05 and 3.5 ± 0.1 (dihaloelimination). This result highlights the potential of this approach to identify 1,2-DCA degradation pathways in the field. In addition, distinct trends were also observed in a multi- (i.e., Δδ2H versus Δδ37Cl versus Δδ13C) isotope plot, which opens further possibilities for pathway identification in future field studies. This is crucial information to understand the mechanisms controlling natural attenuation of 1,2-DCA and to design appropriate strategies to enhance biodegradation.
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Affiliation(s)
- Jordi Palau
- Centre for Hydrogeology and Geothermics, University of Neuchâtel , 2000 Neuchâtel, Switzerland
- Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona , Martí i Franquès s/n, 08028 Barcelona, Spain
- Institute of Environmental Assessment and Water Research (IDAEA), CSIC, and Hydrogeology Group (UPC-CSIC) , Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Orfan Shouakar-Stash
- Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
- Isotope Tracer Technologies Inc. , Waterloo, Ontario N2 V 1Z5, Canada
| | - Siti Hatijah Mortan
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona , Carrer de les Sitges s/n, 08193 Bellaterra, Spain
| | - Rong Yu
- Department of Environmental Engineering and Earth Sciences, Clemson University , Clemson, South Carolina 29634, United States
| | - Monica Rosell
- Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona , Martí i Franquès s/n, 08028 Barcelona, Spain
| | - Ernest Marco-Urrea
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona , Carrer de les Sitges s/n, 08193 Bellaterra, Spain
| | - David L Freedman
- Department of Environmental Engineering and Earth Sciences, Clemson University , Clemson, South Carolina 29634, United States
| | - Ramon Aravena
- Department of Earth and Environmental Sciences, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada
| | - Albert Soler
- Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona , Martí i Franquès s/n, 08028 Barcelona, Spain
| | - Daniel Hunkeler
- Centre for Hydrogeology and Geothermics, University of Neuchâtel , 2000 Neuchâtel, Switzerland
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Lu Q, de Toledo RA, Xie F, Li J, Shim H. Reutilization of waste scrap tyre as the immobilization matrix for the enhanced bioremoval of a monoaromatic hydrocarbons, methyl tert-butyl ether, and chlorinated ethenes mixture from water. Sci Total Environ 2017; 583:88-96. [PMID: 28109662 DOI: 10.1016/j.scitotenv.2017.01.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 01/01/2017] [Accepted: 01/04/2017] [Indexed: 06/06/2023]
Abstract
BTEX (benzene, toluene, ethylbenzene, ortho-, meta-, and para-xylenes), methyl tert-butyl ether (MTBE), cis-1,2-dichloroethylene (cis-DCE), and trichloroethylene (TCE) are among the major soil and groundwater contaminants frequently co-existing, as a result of their widespread uses. Pseudomonas plecoglossicida was immobilized on waste scrap tyre to remove these contaminants mixture from synthetic contaminated water. The microbial activity was enhanced in the immobilized system, shown by the higher colony forming units (CFUs) (40%), while BTEX were used as growth substrates. The adsorption capacity of tyres toward contaminants reached a maximum within one day, with BTEX (76.3%) and TCE (64.3%) showing the highest sorption removal capacities, followed by cis-DCE (30.0%) and MTBE (11.0%). The adsorption data fitted the Freundlich isotherm with a good linear correlation (0.989-0.999) for the initial contaminants concentration range applied (25-125mg/L). The monoaromatic hydrocarbons were almost completely removed in the immobilized system and the favourable removal efficiencies of 78% and 90% were obtained for cis-DCE and TCE, respectively. The hybrid (biological, immobilization/physical, sorption) system was further evaluated with the contaminants spiked intermittently for the stable performance. The addition of mineral salt medium further enhanced the bioremoval of contaminants by stimulating the microbial growth to some extent.
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Affiliation(s)
- Qihong Lu
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR 999078, China; School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
| | - Renata Alves de Toledo
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR 999078, China
| | - Fei Xie
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR 999078, China; Shanxi Academy for Environmental Planning, Taiyuan 030002, China
| | - Junhui Li
- College of Natural Resources and Environmental Science, South China Agricultural University, Guangzhou 510642, China
| | - Hojae Shim
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR 999078, China.
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Wang SY, Chen SC, Lin YC, Kuo YC, Chen JY, Kao CM. Acidification and sulfide formation control during reductive dechlorination of 1,2-dichloroethane in groundwater: Effectiveness and mechanistic study. Chemosphere 2016; 160:216-229. [PMID: 27376861 DOI: 10.1016/j.chemosphere.2016.06.066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/21/2016] [Accepted: 06/17/2016] [Indexed: 06/06/2023]
Abstract
To enhance the reductive dechlorination of 1,2-dichloroethane (DCA) in groundwater, substrate injection may be required. However, substrate biodegradation causes groundwater acidification and sulfide production, which inhibits the bacteria responsible for DCA dechlorination and results in an odor problem. In the microcosm study, the effectiveness of the addition of ferrous sulfate (FS), desulfurization slag (DS), and nanoscale zero-valent iron (nZVI) on acidification and sulfide control was studied during reductive dechlorination of DCA, and the emulsified substrate (ES) was used as the substrate. Up to 94% of the sulfide was removed with FS and DS addition (0.25 wt%) (initial DCA concentration = 13.5 mg/L). FS and DS amendments resulted in the formation of a metal sulfide, which reduced the hydrogen sulfide concentration as well as the subsequent odor problem. Approximately 96% of the DCA was degraded under reductive dechlorination with nZVI or DS addition using ES as the substrate. In microcosms with nZVI or DS addition, the sulfide concentration was reduced to less than 15 μg/L. Acidification can be controlled via hydroxide ions production after nZVI oxidation and reaction of free CaO (released from DS) with water, which enhanced DCA dechlorination. The quantitative polymerase chain reaction results confirmed that the microcosms with nZVI added had the highest Dehalococcoides population (up to 2.5 × 10(8) gene copies/g soil) due to effective acidification control. The α-elimination mechanism was the main abiotic process, and reductive dechlorination dominated by Dehalococcides was the biotic mechanism that resulted in DCA removal. More than 22 bacterial species were detected, and dechlorinating bacteria existed in soils under alkaline and acidic conditions.
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Affiliation(s)
- S Y Wang
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - S C Chen
- Department of Life Sciences, National Central University, Chung-Li, Taiwan
| | - Y C Lin
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Y C Kuo
- Formosa Petrochemical Co., Kaohsiung, Taiwan
| | - J Y Chen
- Formosa Petrochemical Co., Kaohsiung, Taiwan
| | - C M Kao
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
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9
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Munro JE, Liew EF, Ly MA, Coleman NV. A New Catabolic Plasmid in Xanthobacter and Starkeya spp. from a 1,2-Dichloroethane-Contaminated Site. Appl Environ Microbiol 2016; 82:5298-308. [PMID: 27342553 PMCID: PMC4988179 DOI: 10.1128/aem.01373-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 06/13/2016] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED 1,2-Dichloroethane (DCA) is a problematic xenobiotic groundwater pollutant. Bacteria are capable of biodegrading DCA, but the evolution of such bacteria is not well understood. In particular, the mechanisms by which bacteria acquire the key dehalogenase genes dhlA and dhlB have not been well defined. In this study, the genomic context of dhlA and dhlB was determined in three aerobic DCA-degrading bacteria (Starkeya novella strain EL1, Xanthobacter autotrophicus strain EL4, and Xanthobacter flavus strain EL8) isolated from a groundwater treatment plant (GTP). A haloalkane dehalogenase gene (dhlA) identical to the canonical dhlA gene from Xanthobacter sp. strain GJ10 was present in all three isolates, and, in each case, the dhlA gene was carried on a variant of a 37-kb circular plasmid, which was named pDCA. Sequence analysis of the repA replication initiator gene indicated that pDCA was a member of the pTAR plasmid family, related to catabolic plasmids from the Alphaproteobacteria, which enable growth on aromatics, dimethylformamide, and tartrate. Genes for plasmid replication, mobilization, and stabilization were identified, along with two insertion sequences (ISXa1 and ISPme1) which were likely to have mobilized dhlA and dhlB and played a role in the evolution of aerobic DCA-degrading bacteria. Two haloacid dehalogenase genes (dhlB1 and dhlB2) were detected in the GTP isolates; dhlB1 was most likely chromosomal and was similar to the canonical dhlB gene from strain GJ10, while dhlB2 was carried on pDCA and was not closely related to dhlB1 Heterologous expression of the DhlB2 protein confirmed that this plasmid-borne dehalogenase was capable of chloroacetate dechlorination. IMPORTANCE Earlier studies on the DCA-degrading Xanthobacter sp. strain GJ10 indicated that the key dehalogenases dhlA and dhlB were carried on a 225-kb linear plasmid and on the chromosome, respectively. The present study has found a dramatically different gene organization in more recently isolated DCA-degrading Xanthobacter strains from Australia, in which a relatively small circular plasmid (pDCA) carries both dhlA and dhlB homologs. pDCA represents a true organochlorine-catabolic plasmid, first because its only obvious metabolic phenotype is dehalogenation of organochlorines, and second because acquisition of this plasmid provides both key enzymes required for carbon-chlorine bond cleavage. The discovery of the alternative haloacid dehalogenase dhlB2 in pDCA increases the known genetic diversity of bacterial chloroacetate-hydrolyzing enzymes.
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Affiliation(s)
- Jacob E Munro
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
| | - Elissa F Liew
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
| | - Mai-Anh Ly
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
| | - Nicholas V Coleman
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
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10
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Leitão P, Rossetti S, Danko AS, Nouws H, Aulenta F. Enrichment of Dehalococcoides mccartyi spp. from a municipal activated sludge during AQDS-mediated bioelectrochemical dechlorination of 1,2-dichloroethane to ethene. Bioresour Technol 2016; 214:426-431. [PMID: 27155798 DOI: 10.1016/j.biortech.2016.04.129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 04/22/2016] [Accepted: 04/28/2016] [Indexed: 06/05/2023]
Abstract
The application of bioelectrochemical systems (BES) for the treatment of chloroethanes has been so far limited, in spite of the high frequency that these contaminants are detected at contaminated sites. This work studied the biodegradation of 1,2-dichloroethane (1,2-DCA) in a lab-scale BES, inoculated with a municipal activated sludge and operated under a range of conditions, spanning from oxidative to reductive, both in the presence and in the absence of the humic acid analogue anthraquinone-2,6-disulfonate (AQDS) as a redox mediator. The results showed stable dechlorination of 1,2-DCA to ethene (up to 65±5μmol/Ld), when the BES was operated at a set potential of -300mV vs. SHE, in the presence of AQDS. Sustained filled-and-draw operation resulted in the enrichment of Dehalococcoides mccartyi. The results of this work provide new insights into the applicability of BES for groundwater remediation and the potential interaction between biogeochemistry and 1,2-DCA in humics-rich contaminated aquifers.
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Affiliation(s)
- Patrícia Leitão
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km. 29.300, 00015 Monterotondo (RM), Italy; CERENA, Department of Mining Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; REQUIMTE, Institute of Engineering of Porto, Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal
| | - Simona Rossetti
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km. 29.300, 00015 Monterotondo (RM), Italy
| | - Anthony S Danko
- CERENA, Department of Mining Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Henri Nouws
- REQUIMTE, Institute of Engineering of Porto, Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal
| | - Federico Aulenta
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km. 29.300, 00015 Monterotondo (RM), Italy.
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11
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Koenig JC, Boparai HK, Lee MJ, O'Carroll DM, Barnes RJ, Manefield MJ. Particles and enzymes: Combining nanoscale zero valent iron and organochlorine respiring bacteria for the detoxification of chloroethane mixtures. J Hazard Mater 2016; 308:106-112. [PMID: 26808236 DOI: 10.1016/j.jhazmat.2015.12.036] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 11/16/2015] [Accepted: 12/20/2015] [Indexed: 06/05/2023]
Abstract
Nanoscale zero valent iron (nZVI) and organochlorine respiring bacteria (ORB) are two technologies used to detoxify chlorinated aliphatic hydrocarbons (CAHs). nZVI can rapidly detoxify high CAH concentrations, but is quickly oxidised and unable to degrade certain CAHs (e.g., 1,2-dichlorothane). In contrast, ORB can dechlorinate CAHs resistant to nZVI (e.g., 1,2-dichlorothane) but are inhibited by other CAHs of concern degradable by nZVI (e.g., chloroform and carbon tetrachloride). Combining the two was proposed as a unique treatment train to overcome each technology's shortcomings. In this study, this combined remedy was investigated using a mixture of 1,2-dichloroethane, degradable by ORB but not nZVI, and 1,1,2-trichloroethane, susceptible to both. Results indicated that nZVI rapidly dechlorinated 1,1,2-trichloroethane when supplied above 0.5 g/L, however ORB were inhibited and unable to dechlorinate 1,2-dichloroethane. pH increase and ionic species associated with nZVI did not significantly impact ORB, pinpointing Fe(0) particles as responsible for ORB inhibition. Below 0.05 g/L nZVI, ORB activity was stimulated. Results suggest that combining ORB and nZVI at appropriate doses can potentially treat a wider range of CAHs than each individual remedy. At field sites where nZVI was applied, it is likely that in situ nZVI concentrations were below the threshold of negative consequences.
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Affiliation(s)
- Joanna C Koenig
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Kensington, Sydney, NSW 2052, Australia.
| | - Hardiljeet K Boparai
- Dept. of Civil and Environmental Engineering, The University of Western Ontario, London, Ontario N6A 5B9, Canada
| | - Matthew J Lee
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Kensington, Sydney, NSW 2052, Australia
| | - Denis M O'Carroll
- School of Civil and Environmental Engineering, The University of New South Wales, Manly Vale, Sydney, NSW 2093, Australia
| | - Robert J Barnes
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Kensington, Sydney, NSW 2052, Australia
| | - Michael J Manefield
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Kensington, Sydney, NSW 2052, Australia
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12
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Leitão P, Rossetti S, Nouws HPA, Danko AS, Majone M, Aulenta F. Bioelectrochemically-assisted reductive dechlorination of 1,2-dichloroethane by a Dehalococcoides-enriched microbial culture. Bioresour Technol 2015; 195:78-82. [PMID: 26099437 DOI: 10.1016/j.biortech.2015.06.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/04/2015] [Accepted: 06/05/2015] [Indexed: 06/04/2023]
Abstract
The aim of this study was to verify the possibility to use a polarized graphite electrode as an electron donor for the reductive dechlorination of 1,2-dichloroethane, an ubiquitous groundwater contaminant. The rate of 1,2-DCA dechlorination almost linearly increased by decreasing the set cathode potential over a broad range of set cathode potentials (i.e., from -300 mV to -900 mV vs. the standard hydrogen electrode). This process was primarily dependent on electrolytic H2 generation. On the other hand, reductive dechlorination proceeded (although quite slowly) with a very high Coulombic efficiency (near 70%) at a set cathode potential of -300 mV, where no H2 production occurred. Under this condition, reductive dechlorination was likely driven by direct electron uptake from the surface of the polarized electrode. Taken as a whole, this study further extends the range of chlorinated contaminants which can be treated with bioelectrochemical systems.
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Affiliation(s)
- Patrícia Leitão
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km. 29.300, 00015 Monterotondo (RM), Italy; CERENA, Department of Mining Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; REQUIMTE/LAQV, Institute of Engineering of Porto, Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal
| | - Simona Rossetti
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km. 29.300, 00015 Monterotondo (RM), Italy
| | - Henri P A Nouws
- REQUIMTE/LAQV, Institute of Engineering of Porto, Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal
| | - Anthony S Danko
- CERENA, Department of Mining Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Mauro Majone
- Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Federico Aulenta
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km. 29.300, 00015 Monterotondo (RM), Italy.
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13
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Wang SY, Kuo YC, Huang YZ, Huang CW, Kao CM. Bioremediation of 1,2-dichloroethane contaminated groundwater: Microcosm and microbial diversity studies. Environ Pollut 2015; 203:97-106. [PMID: 25863886 DOI: 10.1016/j.envpol.2015.03.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 06/04/2023]
Abstract
In this study, the effectiveness of bioremediating 1,2-dichloroethane (DCA)-contaminated groundwater under different oxidation-reduction processes was evaluated. Microcosms were constructed using indigenous bacteria and activated sludge as the inocula and cane molasses and a slow polycolloid-releasing substrate (SPRS) as the primary substrates. Complete DCA removal was obtained within 30 days under aerobic and reductive dechlorinating conditions. In anaerobic microcosms with sludge and substrate addition, chloroethane, vinyl chloride, and ethene were produced. The microbial communities and DCA-degrading bacteria in microcosms were characterized by 16S rRNA-based denatured-gradient-gel electrophoresis profiling and nucleotide sequence analyses. Real-time polymerase chain reaction was applied to evaluate the variations in Dehalococcoides spp. and Desulfitobacterium spp. Increase in Desulfitobacterium spp. indicates that the growth of Desulfitobacterium might be induced by DCA. Results indicate that DCA could be used as the primary substrate under aerobic conditions. The increased ethene concentrations imply that dihaloelimination was the dominate mechanism for DCA biodegradation.
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Affiliation(s)
- S Y Wang
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Y C Kuo
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Y Z Huang
- Bioenvironmental Engineering Department, Chung Yuan University, Chung Li, Taiwan
| | - C W Huang
- Deaprtment of Biological Science, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - C M Kao
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
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14
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Zhurba OM, Alekseenko AN. [To the question of the optimization of methods for detection of vinyl chloride and 1,2-dichloroethane, and their metabolites in biological fluids in workers involved in production of polyvinyl chloride]. Gig Sanit 2014:116-120. [PMID: 25831943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
There is considered the improvement of methodological approaches to the gas chromatographic methods- of the detection of vinyl chloride and 1,2-dichloroethane and their metabolites--chloroethanol and monochloroacetic acid in biological fluids. There were evaluated such metrological characteristics of methods, as repeatability, interlaboratoty precision, relevance and accuracy. The value of relative expanded uncertainty does not exceed 30%. There are reported optimal regimes of gas chromatographic analysis, conditions for sample preparation. The results of the contents ofthese chemical compounds and their metabolites in biological fluids from persons working in contact with chlorinated hydrocarbons are presented These techniques can be used for the detection ofthe fact of exposure to toxic substances, assessment of the level of exposure and biomonitoring.
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15
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Schmidt M, Lege S, Nijenhuis I. Comparison of 1,2-dichloroethane, dichloroethene and vinyl chloride carbon stable isotope fractionation during dechlorination by two Dehalococcoides strains. Water Res 2014; 52:146-154. [PMID: 24468425 DOI: 10.1016/j.watres.2013.12.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/16/2013] [Accepted: 12/27/2013] [Indexed: 06/03/2023]
Abstract
Carbon stable isotope fractionation during 1,2-dichloroethane (1,2-DCA), dichloroethene (DCE) and vinyl chloride (VC) dechlorination was analysed for two Dehalococcoides strains, Dehalococcoides mccartyi strain 195 (formerly Dehalococcoides ethenogenes strain 195) and D. mccartyi strain BTF08, and used to characterize the reaction. The isotope enrichment factors (εC) determined for 1,2-DCA were -30.8 ± 1.3‰ and -29.0 ± 3.0‰ for D. mccartyi strain BTF08 and D. mccartyi strain 195, respectively. Enrichment factors (εC) determined for chlorinated ethenes with strain BTF08 were -28.8 ± 1.5‰ (VC), -30.5 ± 1.5‰ (cis-DCE) and -12.4 ± 1.1‰ (1,1-DCE). Product, ethene, related enrichment factors (εC1,2-DCA-ethene) calculated for 1,2-DCA (-34.1 and -32.3‰ for strain BTF08 and strain 195, respectively) were similar to substrate based enrichment factors (εC1,2-DCA), supporting the hypothesis that ethene is the direct product of 1,2-DCA dichloroelimination but that VC was a side product as result of branching in the reaction.
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Affiliation(s)
- Marie Schmidt
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
| | - Sascha Lege
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany
| | - Ivonne Nijenhuis
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
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16
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Abstract
Recently, we found that Alcanivorax bacteria from various marine environments were capable of degrading halogenated alkanes. Genome sequencing of A. dieselolei B-5 revealed two putative haloalkane dehalogenase (HLD) genes, which were supposed to be involved in degradation of halogenated compounds. In this report, we confirm for the first time that the Alcanivorax bacterium encodes a truly functional HLD named DadB. An activity assay with 46 halogenated substrates indicated that DadB possesses broad substrate range and has the highest overall activity among the identified HLDs. DadB prefers brominated substrates; chlorinated alkenes; and the C2-C3 substrates, including the persistent pollutants of 1,2-dichloroethane, 1,2-dichloropropane and 1,2,3-trichloropropane. As DadB displays no detectable activity toward long-chain haloalkanes such as 1-chlorohexadecane and 1-chlorooctadecane, the degradation of them in A. dieselolei B-5 might be attributed to other enzymes. Kinetic constants were determined with 6 substrates. DadB has highest affinity and largest kcat/Km value toward 1,3-dibromopropane (Km = 0.82 mM, kcat/Km = 16.43 mM−1·s−1). DadB aggregates fast in the buffers with pH≤7.0, while keeps stable in monomer form when pH≥7.5. According to homology modeling, DadB has an open active cavity with a large access tunnel, which is supposed important for larger molecules as opposed to C2-C3 substrates. Combined with the results for other HLDs, we deduce that residue I247 plays an important role in substrate selection. These results suggest that DadB and its host, A. dieselolei B-5, are of potential use for biocatalysis and bioremediation applications.
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Affiliation(s)
- Anzhang Li
- School of Life Sciences, Xiamen University, Xiamen, China ; Key Laboratory of Marine Biogenetic Resources-State Key Laboratory Breeding Base, Third Institute of Oceanography, State Oceanic Administration, Collaborative Innovation Center of Deep Sea Biology; Key Laboratory of Marine Biogenetic Resources of Fujian Province, Xiamen, China
| | - Zongze Shao
- Key Laboratory of Marine Biogenetic Resources-State Key Laboratory Breeding Base, Third Institute of Oceanography, State Oceanic Administration, Collaborative Innovation Center of Deep Sea Biology; Key Laboratory of Marine Biogenetic Resources of Fujian Province, Xiamen, China
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17
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Munro JE, Liew EF, Coleman NV. Adaptation of a membrane bioreactor to 1,2-dichloroethane revealed by 16S rDNA pyrosequencing and dhlA qPCR. Environ Sci Technol 2013; 47:13668-13676. [PMID: 24175727 DOI: 10.1021/es403292s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A pilot-scale membrane bioreactor (MBR) was tested for bioremediation of 1,2-dichloroethane (DCA) in groundwater. Pyrosequencing of 16S rDNA was used to study changes in the microbiology of the MBR over 137 days, including a 67 day initial adaptation phase of increasing DCA concentration. The bacterial community in the MBR was distinct from those in soil and groundwater at the same site, and was dominated by alpha- and beta- proteobacteria, including Rhodobacter, Methylibium, Rhodopseudomonas, Methyloversatilis, Caldilinea, Thiobacillus, Azoarcus, Hyphomicrobium, and Leptothrix. Biodegradation of DCA in the MBR began after 26 days, and was sustained for the remainder of the experiment. A quantitative PCR (qPCR) assay for the dehalogenase gene dhlA was developed to monitor DCA-degrading bacteria in the MBR, and a positive correlation was seen between dhlA gene abundance and the cumulative amount of DCA that had entered the MBR. Genera previously associated with aerobic DCA biodegradation (Xanthobacter, Ancylobacter, Azoarcus) were present in the MBR, and the abundance of Azoarcus correlated well with dhlA gene abundance. This study shows that MBRs can be an effective method for removal of DCA from groundwater, and that the dhlA qPCR is a rapid and sensitive method for detection of DCA-degrading bacteria.
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Affiliation(s)
- Jacob E Munro
- School of Molecular Bioscience, Building G08, University of Sydney , Darlington, New South Wales, 2006, Australia
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18
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Arjoon A, Olaniran AO, Pillay B. Enhanced 1,2-dichloroethane degradation in heavy metal co-contaminated wastewater undergoing biostimulation and bioaugmentation. Chemosphere 2013; 93:1826-1834. [PMID: 23835411 DOI: 10.1016/j.chemosphere.2013.06.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 05/25/2013] [Accepted: 06/07/2013] [Indexed: 06/02/2023]
Abstract
Biostimulation, bioaugmentation and dual-bioaugmentation strategies were investigated in this study for efficient bioremediation of water co-contaminated with 1,2-dichloroethane (1,2-DCA) and heavy metals, in a microcosm set-up. 1,2-DCA concentration was periodically measured in the microcosms by gas chromatographic analysis of the headspace samples, while bacterial population and diversity were determined by standard plate count technique and Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) analysis, respectively. Dual-bioaugmentation, proved to be most effective exhibiting 22.43%, 26.54%, 19.58% and 30.49% increase in 1,2-DCA degradation in microcosms co-contaminated with As(3+), Cd(2+), Hg(2+) and Pb(2+), respectively, followed by bioaugmentation and biostimulation. Dual-bioaugmented microcosms also exhibited the highest increase in the biodegradation rate constant (k1) resulting in 1.76-, 2-, 1.7- and 2.1-fold increase in As(3+), Cd(2+), Hg(2+) and Pb(2+) co-contaminated microcosms respectively, compared to the untreated microcosms. Dominant bacterial strains obtained from the co-contaminated microcosms were found to belong to the genera Burkholderia, Pseudomonas, Bacillus, Enterobacter and Bradyrhizobium, previously reported for 1,2-DCA and other chlorinated compounds degradation. PCR-DGGE analysis revealed variation in microbial diversity over time in the different co-contaminated microcosms. Results obtained in this study have significant implications for developing innovative bioremediation strategies for treating water co-contaminated with chlorinated organics and heavy metals.
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Affiliation(s)
- Ashmita Arjoon
- Discipline of Microbiology, School of Life Sciences, University of KwaZulu-Natal (Westville Campus), Private Bag X54001, Durban 4000, South Africa
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Take M, Takanobu K, Takeuchi T, Haresaku M, Matsumoto M, Nagano K, Yamamoto S, Fukushima S. Distribution of blood and tissue concentrations in rats by inhalation exposure to 1,2-dichloroethane. J Environ Sci Health A Tox Hazard Subst Environ Eng 2013; 48:1031-1036. [PMID: 23573923 DOI: 10.1080/10934529.2013.773765] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The compound 1,2-dichloroethane (DCE) is a ubiquitous environmental contaminant. The primary route of exposure of humans to DCE is inhalation of its vapor. The present investigation was undertaken to determine the distribution and accumulation of DCE in the blood, lung, liver, brain, kidney and abdominal fat of rats during and after inhalation exposure. Male rats were exposed to 160 ppm (v/v) of DCE vapor for 360 min and the concentrations of DCE in the blood and tissues during the inhalation exposure period and after the end of the exposure period were measured. DCE accumulation in the abdominal fat was much greater than that in the blood and other tissues. The information we obtained in this study is useful basic data pertaining to the pharmacokinetics of DCE and DCE-mediated carcinogenicity: Our results suggest that one of the factors involved in the induction of peritoneal tumors in rats exposed to DCE vapor by inhalation is DCE accumulation in the abdominal fat.
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Affiliation(s)
- Makoto Take
- Japan Bioassay Research Center, Japan Industrial Safety and Health Association, Hadano, Kanagawa, Japan.
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Tang Y, Krajmalnik-Brown R, Rittmann BE. Modeling trichloroethene reduction in a hydrogen-based biofilm. Water Sci Technol 2013; 68:1158-1163. [PMID: 24037169 DOI: 10.2166/wst.2013.362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We constructed a multispecies biofilm model for simultaneous reduction of trichloroethene (TCE) and nitrate (NO3(-)) in the biofilm of a H2-based membrane biofilm reactor (MBfR). The one-dimensional model includes dual-substrate Monod kinetics for a steady-state biofilm with multiple solid and dissolved components. The model has five solid components: autotrophic denitrifying bacteria (ADB), heterotrophic denitrifying bacteria (HDB), Dehalococcoides (DHC), inert biomass (IB), and extracellular polymeric substances (EPS). The model has eight dissolved components: NO3(-), TCE, dichloroethene (DCE), vinyl chloride (VC), ethene, hydrogen (H2), substrate-utilization-associated products (UAP), and biomass-associated products (BAP). We used this model to simulate a bench-scale experiment in a H2-based MBfR. The model simulated the trends well: almost complete removal of nitrate, incomplete reduction of TCE, and almost no accumulation of DCE and VC. To gain insight into reductive dehalogenation in a H2-based MBfR, we also simulated the concentrations of nitrate, TCE, DCE, VC, and ethene in the reactor effluent while varying the influent nitrate concentration. Simultaneous low concentrations of nitrate and the three chlorinated ethenes can occur as long as the influent ratio of NO3(-) to TCE is not too large, so that DHC are a significant fraction of the biofilm.
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Affiliation(s)
- Youneng Tang
- Swette Center for Environmental Biotechnology, Biodesign Institute at Arizona State University, 1001 South McAllister Avenue, Tempe, AZ 85287-5701, USA E-mail:
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21
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Wei YT, Wu SC, Yang SW, Che CH, Lien HL, Huang DH. Biodegradable surfactant stabilized nanoscale zero-valent iron for in situ treatment of vinyl chloride and 1,2-dichloroethane. J Hazard Mater 2012; 211-212:373-380. [PMID: 22118849 DOI: 10.1016/j.jhazmat.2011.11.018] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 11/02/2011] [Accepted: 11/03/2011] [Indexed: 05/31/2023]
Abstract
Nanoscale zero-valent iron (NZVI) stabilized with dispersants is a promising technology for the remediation of contaminated groundwater. In this study, we demonstrated the use of biodegradable surfactant stabilized NZVI slurry for successful treatment of vinyl chloride (VC) and 1,2-dichloroethane (1,2-DCA) in a contaminated site in Taiwan. The biodegradable surfactant stabilized NZVI was coated with palladium and synthesized on-site. From monitoring the iron concentration breakthrough and distribution, it was found that the stabilized NZVI is capable of transporting in the aquifer at the test plot (200 m(2)). VC was effectively degraded by NZVI while the 1,2-DCA degradation was relatively sluggish during the 3-month field test. Nevertheless, as 1,2-DCA is known to resist abiotic reduction by NZVI, the observation of 1,2-DCA degradation and hydrocarbon production suggested a bioremediation took place. ORP and pH results revealed that a reducing condition was achieved at the testing area facilitating the biodegradation of chlorinated organic hydrocarbons. The bioremediation may be attributed to the production of hydrogen gas as electron donor from the corrosion of NZVI in the presence of water or the added biodegradable surfactant serving as the carbon source as well as electron donor to stimulate microbial growth.
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Affiliation(s)
- Yu-Ting Wei
- Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan, ROC
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22
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Olaniran AO, Balgobind A, Pillay B. Quantitative assessment of the toxic effects of heavy metals on 1,2-dichloroethane biodegradation in co-contaminated soil under aerobic condition. Chemosphere 2011; 85:839-847. [PMID: 21762948 DOI: 10.1016/j.chemosphere.2011.06.091] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 06/21/2011] [Accepted: 06/22/2011] [Indexed: 05/31/2023]
Abstract
1,2-Dichloroethane (1,2-DCA) is one of the most hazardous pollutant of soil and groundwater, and is produced in excess of 5.44×10⁹ kg annually. Owing to their toxicity, persistence and potential for bioaccumulation, there is a growing interest in technologies for their removal. Heavy metals are known to be toxic to soil microorganisms at high concentrations and can hinder the biodegradation of organic contaminants. In this study, the inhibitory effect of heavy metals, namely; arsenic, cadmium, mercury and lead, on the aerobic biodegradation of 1,2-DCA by autochthonous microorganisms was evaluated in soil microcosm setting. The presence of heavy metals was observed to have a negative impact on the biodegradation of 1,2-DCA in both soil samples tested, with the toxic effect being more pronounced in loam soil, than in clay soil. Generally, 75 ppm As³⁺, 840 ppm Hg²⁺, and 420 ppm Pb²⁺ resulted in 34.24%, 40.64%, and 45.94% increase in the half live (t½) of 1,2-DCA, respectively, in loam soil, while concentrations above 127.5 ppm Cd²⁺, 840 ppm Hg²⁺ and 420 ppm of Pb²⁺ and less than 75 ppm As³⁺ was required to cause a >10% increase in the t½ of 1,2-DCA in clay soil. A dose-dependent relationship between degradation rate constant (k₁) of 1,2-DCA and metal ion concentrations was observed for all the heavy metals tested, except for Hg²⁺. This study demonstrated that different heavy metals have different impacts on the degree of 1,2-DCA degradation. Results also suggest that the degree of inhibition is metal specific and is also dependent on several factors including; soil type, pH, moisture content and available nutrients.
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Affiliation(s)
- Ademola Olufolahan Olaniran
- Discipline of Microbiology, School of Biochemistry, Genetics and Microbiology, Faculty of Science and Agriculture, University of KwaZulu-Natal (Westville Campus), Durban 4000, South Africa.
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Elango V, Kurtz HD, Freedman DL. Aerobic cometabolism of trichloroethene and cis-dichloroethene with benzene and chlorinated benzenes as growth substrates. Chemosphere 2011; 84:247-253. [PMID: 21531438 DOI: 10.1016/j.chemosphere.2011.04.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 04/01/2011] [Accepted: 04/02/2011] [Indexed: 05/30/2023]
Abstract
Using inoculum from a microcosm study that exhibited aerobic transformation of cis-1,2-dichloroethene (cDCE) and trichloroethene (TCE) commensurate with biodegradation of monoaromatic compounds, enrichment cultures were developed by providing benzene, chlorobenzene (CB), dichlorobenzene (DCB) isomers and 1,2,4-trichlorobenzene as carbon and energy sources. Isolates that grow on benzene, CB, 1,2-DCB and 1,3-DCB were identified as Rhodococcus, Ralstonia, Variovorax and Ralstonia spp., respectively. Cometabolic transformation of cDCE and TCE by resting cells was demonstrated. Transformation capacities (T(c)=0.47-1.0 μg TCE mg(-1)biomass; 1.3-5.3 μg cDCE mg(-1)biomass), transformation yields (T(y)=0.18-0.27 μg TCE mg(-1)substrate; 0.46-2.1 μg cDCE mg(-1)substrate), and pseudo-first-order cometabolic degradation rate constants (0.00081-0.0031 L mg TCE(-1)d(-1); 0.0012-0.030 L mg cDCE(-1)d(-1)) for resting cells grown on benzene, CB, 1,2-DCB and 1,3-DCB were generally lower in comparison to phenol and toluene-grown isolates. Cometabolic transformation of cDCE and TCE also occurred while the cultures concurrently consumed their growth substrate (T(c)(')=0.15-0.33 μg TCE mg(-1)biomass; 4.9-11 μg cDCE mg(-1)biomass; T(y)(')=0.06-0.11 μg TCE mg(-1)substrate; 1.7-4.6 μg cDCE mg(-1)substrate), a condition that is more likely to be encountered in situ compared to cometabolic transformations by resting cells. This study is the first to report transformation rates, capacities, and yields for cometabolism of cDCE and TCE during aerobic growth on benzene, CB, 1,2-DCB and 1,3-DCB. This type of information is needed to predict the potential for natural attenuation when these compounds occur as co-contaminants.
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Affiliation(s)
- Vijai Elango
- Hazardous Substance Research Center/South and Southwest, 3221 Patrick Taylor Hall, Baton Rouge, LA 70803, USA.
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Knapp JE, Pahl R, Cohen J, Nichols JC, Schulten K, Gibson QH, Srajer V, Royer WE. Ligand migration and cavities within Scapharca Dimeric HbI: studies by time-resolved crystallo-graphy, Xe binding, and computational analysis. Structure 2010; 17:1494-504. [PMID: 19913484 DOI: 10.1016/j.str.2009.09.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 08/25/2009] [Accepted: 09/09/2009] [Indexed: 11/19/2022]
Abstract
As in many other hemoglobins, no direct route for migration of ligands between solvent and active site is evident from crystal structures of Scapharca inaequivalvis dimeric HbI. Xenon (Xe) and organic halide binding experiments, along with computational analysis presented here, reveal protein cavities as potential ligand migration routes. Time-resolved crystallographic experiments show that photodissociated carbon monoxide (CO) docks within 5 ns at the distal pocket B site and at more remote Xe4 and Xe2 cavities. CO rebinding is not affected by the presence of dichloroethane within the major Xe4 protein cavity, demonstrating that this cavity is not on the major exit pathway. The crystal lattice has a substantial influence on ligand migration, suggesting that significant conformational rearrangements may be required for ligand exit. Taken together, these results are consistent with a distal histidine gate as one important ligand entry and exit route, despite its participation in the dimeric interface.
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Affiliation(s)
- James E Knapp
- Department of Biochemistry and Molecular Pharmacology, The University of Massachusetts Medical School, Worcester, MA 01605, USA
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25
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van der Zaan B, de Weert J, Rijnaarts H, de Vos WM, Smidt H, Gerritse J. Degradation of 1,2-dichloroethane by microbial communities from river sediment at various redox conditions. Water Res 2009; 43:3207-3216. [PMID: 19501382 DOI: 10.1016/j.watres.2009.04.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 04/20/2009] [Accepted: 04/22/2009] [Indexed: 05/27/2023]
Abstract
Insight into the pathways of biodegradation and external factors controlling their activity is essential in adequate environmental risk assessment of chlorinated aliphatic hydrocarbon pollution. This study focuses on biodegradation of 1,2-dichloroethane (1,2-DCA) in microcosms containing sediment sourced from the European rivers Ebro, Elbe and Danube. Biodegradation was studied under different redox conditions. Reductive dechlorination of 1,2-DCA was observed with Ebro and Danube sediment with chloroethane, or ethene, respectively, as the major dechlorination products. Different reductively dehalogenating micro-organisms (Dehalococcoides spp., Dehalobacter spp., Desulfitobacterium spp. and Sulfurospirillum spp.) were detected by 16S ribosomal RNA gene-targeted PCR and sequence analyses of 16S rRNA gene clone libraries showed that only 2-5 bacterial orders were represented in the microcosms. With Ebro and Danube sediment, indications for anaerobic oxidation of 1,2-DCA were obtained under denitrifying or iron-reducing conditions. No biodegradation of 1,2-DCA was observed in microcosms with Ebro sediment under the different tested redox conditions. This research shows that 1,2-DCA biodegradation capacity was present in different river sediments, but not in the water phase of the river systems and that biodegradation potential with associated microbial communities in river sediments varies with the geochemical properties of the sediments.
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Affiliation(s)
- Bas van der Zaan
- Soil and Ground Water Systems, TNO Built Environment and Geosciences, Princetonlaan 6, 3584 CB Utrecht, the Netherlands.
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Davis GB, Patterson BM, Johnston CD. Aerobic bioremediation of 1,2 dichloroethane and vinyl chloride at field scale. J Contam Hydrol 2009; 107:91-100. [PMID: 19428139 DOI: 10.1016/j.jconhyd.2009.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 04/06/2009] [Accepted: 04/07/2009] [Indexed: 05/27/2023]
Abstract
Aerobic bioremediation of 1,2 dichloroethane (1,2 DCA) and vinyl chloride (VC) was evaluated at field scale in a layered, silty and fine-sand anaerobic aquifer. Maximum concentrations of 1,2 DCA (2 g/L) and VC (0.75 g/L) in groundwater were within 25% and 70% of pure compound solubility, respectively. Aerobic conditions were induced by injecting air into sparging wells screened 20.5-21.5 m below ground (17-18 m below the water table). Using a cycle of 23 h of air injection followed by three days of no air injection, fifty days of air injection were accumulated over a 12 month period which included some longer periods of operational shutdown. Oxygen and volatile organic compound probes, and multilevel samplers were used to determine changes of the primary contaminants and the associated inorganic chemistry at multiple locations and depths. Air (oxygen) was distributed laterally up to 25 m from the sparge points, with oxygen partial pressures up to 0.7 atmospheres (28-35 mg/L in groundwater) near to the sparge points. The dissolved mass of 1,2 DCA and VC was reduced by greater than 99% over the 590 m(2) trial plot. Significantly, pH declined from nearly 11 to less than 9, and sulfate concentrations increased dramatically, suggesting the occurrence of mineral sulfide (e.g., pyrite) oxidation. Chloride and bicarbonate (aerobic biodegradation by-products) concentration increases were used to estimate that 300-1000 kg of chlorinated hydrocarbons were biodegraded, although the ratio of 1,2 DCA to VC that was biodegraded remained uncertain. The mass biodegraded was comparable but less than the 400-1400 kg of chlorinated compounds removed from the aqueous phase within a 10,000 m(3) volume of the aquifer. Due to the likely presence of non-aqueous phase liquid, the relative proportion of volatilisation compared to biodegradation could not be determined. The aerobic biodegradation rates were greater than those previously estimated from laboratory-based studies.
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Pham H, Boon N, Marzorati M, Verstraete W. Enhanced removal of 1,2-dichloroethane by anodophilic microbial consortia. Water Res 2009; 43:2936-2946. [PMID: 19443006 DOI: 10.1016/j.watres.2009.04.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 04/02/2009] [Accepted: 04/02/2009] [Indexed: 05/27/2023]
Abstract
1,2-Dichloroethane (1,2-DCA) is a well-known recalcitrant groundwater contaminant. New environment-friendly approaches for the removal of 1,2-DCA that does not bring about volatilization of the compound are required. In this study, different anodophilic consortia enriched in microbial fuel cells (MFCs) operated under airtight conditions were shown to effectively degrade 1,2-DCA (up to 102mg per liter reactor volume per day), while concomitantly generating a current. An anodophilic consortium previously enriched with acetate as the electron donor changed its composition at the rate of 48% per week and increased its richness (Rr) 3-fold, upon adapting to 1,2-DCA as the new electron donor. After being stable, during 1month of operation, it removed up to 95% of the 1,2-DCA amount in the medium in the first 2weeks, while converting 43+/-4% of electrons available from the removal to electricity. A natural consortium from a 1,2-DCA contaminated site changed its composition at the rate of 9% per week and increased its Rr 2-fold, upon adapting to the MFC anode conditions with 1,2-DCA as the electron donor. After being stable, during 1month of operation, it removed up to 85% of the 1,2-DCA amount in the medium in the first 2weeks and the coulombic efficiency was 25+/-4%. The operation of the MFCs under closed circuit conditions resulted in higher 1,2-DCA removal rates than the operation under open circuit conditions, indicating that bioelectrochemical activities enhanced the removal of 1,2-DCA in the MFC anode. The production of ethylene glycol, acetate and carbon dioxide indicated that the anodophilic bacteria oxidatively metabolized 1,2-DCA, probably by means of a hydrolysis-based pathway. The results show that MFCs can be potentially used as a practically convenient technology for the biological removal of 1,2-DCA.
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Affiliation(s)
- Hai Pham
- Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, B 9000 Gent, Belgium
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James CA, Strand SE. Phytoremediation of small organic contaminants using transgenic plants. Curr Opin Biotechnol 2009; 20:237-41. [PMID: 19342219 PMCID: PMC2857588 DOI: 10.1016/j.copbio.2009.02.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 02/19/2009] [Accepted: 02/26/2009] [Indexed: 11/18/2022]
Abstract
The efficacy of transgenic plants in the phytoremediation of small organic contaminants has been investigated. Two principal strategies have been pursued (1) the manipulation of phase I metabolic activity to enhance in planta degradation rates, or to impart novel metabolic activity, and (2) the enhanced secretion of reactive enzymes from roots leading to accelerated ex planta degradation of organic contaminants. A pair of dehalogenase genes from Xanthobacter autotrophicus was expressed in tobacco resulting in the dehalogenation of 1,2-dichloroethane, which was otherwise recalcitrant. A laccase gene from cotton was overexpressed in Arabidopsis thaliana resulting in increased secretory laccase activity and the enhanced resistance to trichlorophenol in soils. Although the results to date are promising, much of the work has been limited to laboratory settings; field demonstrations are needed.
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Affiliation(s)
- C Andrew James
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA 98195, USA
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Abstract
1,2-Dichloroethane (DCA), a potential mutagen and carcinogen, is commonly introduced into the environment through its industrial and agricultural use. In this study, the impact of lead and mercury on DCA degradation in soil was investigated, owing to the complex co-contamination problem frequently encountered in most sites. 1,2-Dichloroethane was degraded readily in both contaminated loam and clay soils with the degradation rate constants ranging between 0.370-0.536 week(-1) and 0.309-0.417 week(-1), respectively. The presence of heavy metals have a negative impact on DCA degradation in both soil types, resulting in up to 24.11% reduction in DCA degradation within one week. Both biostimulation and treatment additives increased DCA degradation, with the best degradation observed upon addition of glucose and a combination of diphosphate salt and sodium chloride, leading to about 17.91% and 43.50% increase in DCA degradation, respectively. The results have promising potential for effective remediation of soils co-contaminated with chlorinated organics and heavy metals. However, the best bioremediation strategy will depend on the soil types, microbial population present in the soil matrices, nutrients availability and metal forms.
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Affiliation(s)
- Ademola O Olaniran
- Discipline of Microbiology, School of Biochemistry, Genetics, Microbiology and Plant Pathology, Faculty of Science and Agriculture, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, Republic of South Africa.
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Mena-Benitez GL, Gandia-Herrero F, Graham S, Larson TR, McQueen-Mason SJ, French CE, Rylott EL, Bruce NC. Engineering a catabolic pathway in plants for the degradation of 1,2-dichloroethane. Plant Physiol 2008; 147:1192-8. [PMID: 18467461 PMCID: PMC2442539 DOI: 10.1104/pp.108.119008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 04/29/2008] [Indexed: 05/05/2023]
Abstract
Plants are increasingly being employed to clean up environmental pollutants such as heavy metals; however, a major limitation of phytoremediation is the inability of plants to mineralize most organic pollutants. A key component of organic pollutants is halogenated aliphatic compounds that include 1,2-dichloroethane (1,2-DCA). Although plants lack the enzymatic activity required to metabolize this compound, two bacterial enzymes, haloalkane dehalogenase (DhlA) and haloacid dehalogenase (DhlB) from the bacterium Xanthobacter autotrophicus GJ10, have the ability to dehalogenate a range of halogenated aliphatics, including 1,2-DCA. We have engineered the dhlA and dhlB genes into tobacco (Nicotiana tabacum 'Xanthi') plants and used 1,2-DCA as a model substrate to demonstrate the ability of the transgenic tobacco to remediate a range of halogenated, aliphatic hydrocarbons. DhlA converts 1,2-DCA to 2-chloroethanol, which is then metabolized to the phytotoxic 2-chloroacetaldehyde, then chloroacetic acid, by endogenous plant alcohol dehydrogenase and aldehyde dehydrogenase activities, respectively. Chloroacetic acid is dehalogenated by DhlB to produce the glyoxylate cycle intermediate glycolate. Plants expressing only DhlA produced phytotoxic levels of chlorinated intermediates and died, while plants expressing DhlA together with DhlB thrived at levels of 1,2-DCA that were toxic to DhlA-expressing plants. This represents a significant advance in the development of a low-cost phytoremediation approach toward the clean-up of halogenated organic pollutants from contaminated soil and groundwater.
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Hirschorn SK, Dinglasan-Panlilio MJ, Edwards EA, Lacrampe-Couloume G, Sherwood Lollar B. Isotope analysis as a natural reaction probe to determine mechanisms of biodegradation of 1,2-dichloroethane. Environ Microbiol 2008; 9:1651-7. [PMID: 17564600 DOI: 10.1111/j.1462-2920.2007.01282.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
1,2-Dichloroethane (1,2-DCA), a chlorinated aliphatic hydrocarbon, is a well-known groundwater contaminant. In this study, fractionation of stable carbon isotope values of 1,2-DCA during biodegradation was used as a novel reaction probe to provide information about the mechanism of 1,2-DCA biodegradation under both aerobic (O2-reducing) and anaerobic (NO3-reducing) conditions. Under O2-reducing conditions, an isotopic enrichment value (epsilon) of -25.8 +/- 1.1 per thousand (+/-95% confidence intervals) was measured for the enrichment culture. Under NO3-reducing conditions, an epsilon-value of -25.8 +/- 3.5 per thousand was measured. The microbial culture produced isotopic enrichment values (epsilon) that are not only large and reproducible, but also are the same whether O2 or NO3 was used as an electron acceptor. Combining data measured under both O2- and NO3-reducing conditions, an isotopic enrichment value (epsilon) of -25.8 +/- 1.6 per thousand is measured for the microbial culture during 1,2-DCA degradation. The epsilon-value can be converted into a kinetic isotope effect (KIE) value to relate the observed isotopic fractionation to the mechanism of degradation. This KIE value (1.05) is consistent with degradation via hydrolytic dehalogenation under both electron-accepting conditions. This study demonstrates the added value of compound-specific isotope analysis not only as a technique to verify the occurrence and extent of biodegradation in the field, but also as a natural reaction probe to provide insight into the enzymatic mechanism of contaminant degradation.
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Affiliation(s)
- Sarah K Hirschorn
- Stable Isotope Laboratory, Department of Geology, University of Toronto, Toronto, ON, Canada
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Henderson JK, Freedman DL, Falta RW, Kuder T, Wilson JT. Anaerobic biodegradation of ethylene dibromide and 1,2-dichloroethane in the presence of fuel hydrocarbons. Environ Sci Technol 2008; 42:864-870. [PMID: 18323114 DOI: 10.1021/es0712773] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Field evidence from underground storage tank sites where leaded gasoline leaked indicates the lead scavengers 1,2-dibromoethane (ethylene dibromide, or EDB) and 1,2-dichloroethane (1,2-DCA) may be present in groundwater at levels that pose unacceptable risk. These compounds are seldom tested for at UST sites. Although dehalogenation of EDB and 1,2-DCA is well established, the effect of fuel hydrocarbons on their biodegradability under anaerobic conditions is poorly understood. Microcosms (2 L glass bottles) were prepared with soil and groundwater from a UST site in Clemson, South Carolina, using samples collected from the source (containing residual fuel) and less contaminated downgradient areas. Anaerobic biodegradation of EDB occurred in microcosms simulating natural attenuation, but was more extensive and predictable in treatments biostimulated with lactate. In the downgradient biostimulated microcosms, EDB decreased below its maximum contaminant level (MCL) (0.05 microg/L) at a first order rate of 9.4 +/- 0.2 yr(-1). The pathway for EDB dehalogenation proceeded mainly by dihaloelimination to ethene in the source microcosms, while sequential hydrogenolysis to bromoethane and ethane was predominant in the downgradient treatments. Biodegradation of EDB in the source microcosms was confirmed by carbon specific isotope analysis, with a delta13C enrichment factor of -5.6 per thousand. The highest levels of EDB removal occurred in microcosms that produced the highest amounts of methane. Extensive biodegradation of benzene, ethylbenzene, toluene and ortho-xylene was also observed in the source and downgradient area microcosms. In contrast, biodegradation of 1,2-DCA proceeded at a considerably slower rate than EDB, with no response to lactate additions. The slower biodegradation rates for 1,2-DCA agree with field observations and indicate that even if EDB is removed to below its MCL, 1,2-DCA may persist.
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Affiliation(s)
- James K Henderson
- Department of Environmental Engineering and Earth Sciences, Clemson University, Clemson, South Carolina 29634-5002, USA.
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Watanabe K, Liberman RG, Skipper PL, Tannenbaum SR, Guengerich FP. Analysis of DNA adducts formed in vivo in rats and mice from 1,2-dibromoethane, 1,2-dichloroethane, dibromomethane, and dichloromethane using HPLC/accelerator mass spectrometry and relevance to risk estimates. Chem Res Toxicol 2007; 20:1594-600. [PMID: 17907789 DOI: 10.1021/tx700125p] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Dihaloalkanes are of toxicological interest because of their high-volume use in industry and their abilities to cause tumors in rodents, particularly dichloromethane and 1,2-dichloroethane. The brominated analogues are not used as extensively but are known to produce more toxicity in some systems. Rats and mice were treated i.p. with (14)C-dichloromethane, -dibromomethane, -1,2-dichloroethane, or -1,2-dibromoethane [5 mg (kg body weight)(-1)], and livers and kidneys were collected to rapidly isolate DNA. The DNA was digested using a procedure designed to minimize processing time, because some of the potential dihalomethane-derived DNA-glutathione (GSH) adducts are known to be unstable, and the HPLC fractions corresponding to major adduct standards were separated and analyzed for (14)C using accelerator mass spectrometry. The level of liver or kidney S-[2-(N(7)-guanyl)ethyl]GSH in rats treated with 1,2-dibromoethane was approximately 1 adduct/10(5) DNA bases; in male or female mice, the level was approximately one-half of this. The levels of 1,2-dichloroethane adducts were 10-50-fold lower. None of four known (in vitro) GSH-DNA adducts was detected at a level of >2/10(8) DNA bases from dibromomethane or dichloromethane. These results provide parameters for risk assessment of these compounds: DNA binding occurs with 1,2-dichloroethane but is considerably less than from 1,2-dibromoethane in vivo, and low exposure to dihalomethanes does not produce appreciable DNA adduct levels in rat or mouse liver and kidney of the doses used. The results may be used to address issues in human risk assessment.
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Affiliation(s)
- Kengo Watanabe
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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Mileva A, Sapundzhiev T, Beschkov V. Modeling 1,2-dichloroethane biodegradation by Klebsiella oxytoca va 8391 immobilized on granulated activated carbon. Bioprocess Biosyst Eng 2007; 31:75-85. [PMID: 17690915 DOI: 10.1007/s00449-007-0148-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 07/13/2007] [Indexed: 11/28/2022]
Abstract
A mathematical model of the biodegradation of xenobiotics by microbial cells attached to particles of granulated activated carbon was developed. The model allowed the quantitative evaluation of different characteristics of the biofilm behavior: retarded microbial growth, increased concentration of immobilized cells compared to suspended cultures, potential cell detachment from the solid support and consequent independent growth of free cells. The applicability of the model was demonstrated for our own experimental data for 1,2- dichloroethane (DCA) biodegradation by Klebsiella oxytoca VA 8391 cells attached to granulated activated carbon. Two types of reactors, recirculated batch and continuous flow bioreactor, were studied. It was shown that in all investigated cases, the major contribution to DCA biodegradation was provided by the immobilized cells. Furthermore, immobilized cells were found to tolerate much higher substrate concentration and dilution rates in continuous culture than the free cells.
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Affiliation(s)
- A Mileva
- Institute of Chemical Engineering, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria
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Abstract
The catalytic site of haloalkane dehalogenase DhlA is buried more than 10 A from the protein surface. While potential access channels to this site have been reported, the precise mechanism of substrate import and product export is still unconfirmed. We used computational methods to examine surface pockets and their putative roles in ligand access to and from the catalytic site. Computational solvent mapping moves small organic molecule as probes over the protein surface in order to identify energetically favorable sites, that is, regions that tend to bind a variety of molecules. The mapping of three DhlA structures identifies seven such regions, some of which have been previously suggested to be involved in the binding and the import/export of substrates or products. These sites are the active site, the putative entrance of the channel leading to the active site, two pockets that bind Br- ions, a pocket in the slot region, and two additional sites between the main domain and the cap of DhlA. We also performed mapping and free energy analysis of the DhlA structures using the substrate, 1,2-dichloroethane, and halide ions as probes. The findings were compared to crystallographic data and to results obtained by CAVER, a program developed for finding routes from protein clefts and cavities to the surface. Solvent mapping precisely reproduced all three Br- binding sites identified by protein crystallography and the openings to four channels found by CAVER. The analyses suggest that (i) the active site has the highest affinity for the substrate molecule, (ii) the substrate initially binds at the entrance of the main tunnel, (iii) the site Br2, close to the entrance, is likely to serve as an intermediate binding site in product export, (iv) the site Br3, induced in the structure at high concentrations of Br-, could be part of an auxiliary route for product release, and (v) three of the identified sites are likely to be entrances of water-access channels leading to the active site. For comparison, we also mapped haloalkane dehalogenases DhaA and LinB, both of which contain significantly larger and more solvent accessible binding sites than DhlA. The mapping of DhaA and LinB places the majority of probes in the active site, but most of the other six regions consistently identified in DhlA were not observed, suggesting that the more open active site eliminates the need for intermediate binding sites for the collision complex seen in DhlA.
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Affiliation(s)
- Michael Silberstein
- Bioinformatics Program, Boston University, 44 Cummington Street, Boston, Massachusetts 02215, USA
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van Breukelen BM. Extending the Rayleigh equation to allow competing isotope fractionating pathways to improve quantification of biodegradation. Environ Sci Technol 2007; 41:4004-10. [PMID: 17612182 DOI: 10.1021/es0628452] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The Rayleigh equation relates the change in isotope ratio of an element in a substrate to the extent of substrate consumption via a single kinetic isotopic fractionation factor (alpha). Substrate consumption is, however, commonly distributed over several metabolic pathways each potentially having a different alpha. Therefore, extended Rayleigh-type equations were derived to account for multiple competing degradation pathways. The value of alpha as expressed in the environment appears a function of the alpha values and rate constants of the various involved degradation pathways. Remarkably, the environmental or apparent alpha value changes and shows non-Rayleigh behavior over a large and relevant concentration interval if Monod kinetics applies and the half-saturation constants of the competing pathways differ. Derived equations were applied to previously published data and enabled (i) quantification of the share that two competing degradation pathways had on aerobic 1,2-dichloroethane (1,2-DCA) biodegradation in laboratory batch experiments and (ii) calculation of the extent of methyl tert-butyl ether (MTBE) biodegradation shared over aerobic and anaerobic degradation at a field site by means of an improved solution to two-dimensional (carbon and hydrogen) compound-specific isotope analysis (CSIA).
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Affiliation(s)
- Boris M van Breukelen
- Department of Hydrology and Geo-Environmental Sciences, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands.
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Duhamel M, Edwards EA. Growth and yields of dechlorinators, acetogens, and methanogens during reductive dechlorination of chlorinated ethenes and dihaloelimination of 1 ,2-dichloroethane. Environ Sci Technol 2007; 41:2303-10. [PMID: 17438779 DOI: 10.1021/es062010r] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The population dynamics of a mixed microbial culture dechlorinating trichloroethene (TCE), cis-1,2-dichloroethene (cDCE), 1,2-dichloroethane (1,2-DCA), and vinyl chloride (VC) to ethene were studied. Quantitative PCR revealed that Dehalococcoides, Geobacter, Sporomusa, Spirochaetes, and Methanomicrobiales phylotypes grew in short-term experiments. Both Geobacter and Dehalococcoides populations grew during TCE dechlorination to cDCE, but only Dehalococcoides populations grew during further dechlorination to ethene. The cell yields for Dehalococcoides determined in this study were similar on an electron equivalent basis regardless of the chlorinated compound transformed: (0.9+/-0.3) x 10(8)16S rRNA gene copies/microelectron equivalent (microeeq) ethene produced during cDCE dechlorination, (1.5 +/-0.3) x 10(8) copies/microeeq ethene produced during VC dechlorination, and (1.6+/-0.8) x 10(8) copies/ u,eeq ethene produced during 1,2-DCA dihaloelimination. The yield for the Geobacter population on TCE was estimated to be (1+/-0.5) x 10(8) copies/microeeq cDCE produced. Calculations showed that the Geobacter population was likely responsible for approximately 80% of the TCE dechlorinated to cDCE in this experiment. Acetogenesis by a Sporomusa population was the main competition to dechlorination for reducing equivalents. Sporomusa did not transform any chlorinated substrates tested, but was capable of converting methanol to acetate and hydrogen for dechlorination. Understanding the functions of various populations in mixed communities may explain why Dehalococcoides spp. are active at some sites and not others, and may also assist in optimizing the growth of bioaugmentation cultures, both in the laboratory and in the field.
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Affiliation(s)
- Melanie Duhamel
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
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Marzorati M, de Ferra F, Van Raemdonck H, Borin S, Allifranchini E, Carpani G, Serbolisca L, Verstraete W, Boon N, Daffonchio D. A novel reductive dehalogenase, identified in a contaminated groundwater enrichment culture and in Desulfitobacterium dichloroeliminans strain DCA1, is linked to dehalogenation of 1,2-dichloroethane. Appl Environ Microbiol 2007; 73:2990-9. [PMID: 17351102 PMCID: PMC1892866 DOI: 10.1128/aem.02748-06] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A mixed culture dechlorinating 1,2-dichloroethane (1,2-DCA) to ethene was enriched from groundwater that had been subjected to long-term contamination. In the metagenome of the enrichment, a 7-kb reductive dehalogenase (RD) gene cluster sequence was detected by inverse and direct PCR. The RD gene cluster had four open reading frames (ORF) showing 99% nucleotide identity with pceB, pceC, pceT, and orf1 of Dehalobacter restrictus strain DSMZ 9455(T), a bacterium able to dechlorinate chlorinated ethenes. However, dcaA, the ORF encoding the catalytic subunit, showed only 94% nucleotide and 90% amino acid identity with pceA of strain DSMZ 9455(T). Fifty-three percent of the amino acid differences were localized in two defined regions of the predicted protein. Exposure of the culture to 1,2-DCA and lactate increased the dcaA gene copy number by 2 log units, and under these conditions the dcaA and dcaB genes were actively transcribed. A very similar RD gene cluster with 98% identity in the dcaA gene sequence was identified in Desulfitobacterium dichloroeliminans strain DCA1, the only known isolate that selectively dechlorinates 1,2-DCA but not chlorinated ethenes. The dcaA gene of strain DCA1 possesses the same amino acid motifs as the new dcaA gene. Southern hybridization using total genomic DNA of strain DCA1 with dcaA gene-specific and dcaB- and pceB-targeting probes indicated the presence of two identical or highly similar dehalogenase gene clusters. In conclusion, these data suggest that the newly described RDs are specifically adapted to 1,2-DCA dechlorination.
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Affiliation(s)
- Massimo Marzorati
- DESTAM, Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy
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Koutinas M, Baptista IIR, Peeva LG, Ferreira Jorge RM, Livingston AG. The use of an oil absorber as a strategy to overcome starvation periods in degrading 1,2-dichloroethane in waste gas. Biotechnol Bioeng 2007; 96:673-86. [PMID: 16937409 DOI: 10.1002/bit.21133] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This work investigates the use of an oil absorber as an operational strategy in vapor phase bioreactors exposed to starvation periods, during the treatment of inhibitory pollutants. After being exposed to 1,2-dichloroethane (DCE) starvation periods, the response and stability of a combined oil-absorber-bioscrubber (OAB) system was compared to that of a bioscrubber only (BO) system. In the BO system, after a 5.2 days starvation period, the DCE removal efficiency was reduced to 12%, and 6 days were needed to recover the initial removal efficiency when the DCE feed resumed. The total organic discharged (TOD(DCE)) was 16,500 g(DCE) m(bioscrubber) (-3) after the DCE starvation. Biomass analysis performed using fluorescence in situ hybridisation (FISH) showed that the microbial activity was significantly reduced during the starvation period and that 5 days were needed to recover the initial activity, after the re-introduction of DCE. In contrast, the performance of the OAB system was stable during 5.2 days of DCE starvation. The DCE removal efficiency was not affected when the DCE feed resumed and the TOD(DCE) was significantly reduced to 2,850 g(DCE) m(bioscrubber) (-3). During starvation, the activity of the microbial culture in the OAB system showed a substantially lower decrease than in the BO system and recovered almost immediately the initial activity after the re-introduction of DCE. Additionally, a mathematical model describing the performance of the OAB system was developed. The results of this study show that the OAB system can effectively sustain the biological treatment of waste gas during starvation periods of inhibitory pollutants.
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Affiliation(s)
- Michalis Koutinas
- Department of Chemical Engineering and Chemical Technology, Imperial College London, SW7 2AZ London, United Kingdom
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Van Raemdonck H, Maes A, Ossieur W, Verthé K, Vercauteren T, Verstraete W, Boon N. Real time PCR quantification in groundwater of the dehalorespiring Desulfitobacterium dichloroeliminans strain DCA1. J Microbiol Methods 2006; 67:294-303. [PMID: 16750582 DOI: 10.1016/j.mimet.2006.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Revised: 04/06/2006] [Accepted: 04/07/2006] [Indexed: 11/26/2022]
Abstract
Quantifying microorganisms responsible for bioremediation can provide insight in their behavior and can help to obtain a better understanding of the physicochemical parameters monitored during bioremediation. A real time PCR (RTm PCR) assay based on the detection with SYBR Green I was optimized in order to quantify the 1,2-dichloroethane dehalorespiring Desulfitobacterium dichloroeliminans strain DCA1. A primer pair targeting unique regions of the 16 S rRNA gene was designed and tested in silico for its specificity. Selectivity was furthermore evaluated and a Limit of Quantification of 1.5 x 10(4) cells/microL DNA extract was obtained for spiked groundwater. Real time measurements of groundwater samples retrieved from a bioaugmented monitoring well and which had an average concentration lying in the range of the Limit of Quantification were evaluated positively with regards to reproducibility. Validation of the RTm PCR assay on groundwater samples originating from different sites confirmed the specificity of the designed primer pair. This RTm PCR assay can be used to survey the abundance and kinetics of strain DCA1 in in situ bioaugmentation field studies.
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Affiliation(s)
- Hilde Van Raemdonck
- Ghent University, Laboratory of Microbial Ecology and Technology, Coupure Links 653, B-9000 Gent, Belgium
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Maes A, Van Raemdonck H, Smith K, Ossieur W, Lebbe L, Verstraete W. Transport and activity of Desulfitobacterium dichloroeliminans strain DCA1 during bioaugmentation of 1,2-DCA-contaminated groundwater. Environ Sci Technol 2006; 40:5544-52. [PMID: 16999138 DOI: 10.1021/es060953i] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The transport and activity of Desulfitobacterium dichloroeliminans strain DCA1 in 1,2-dichloroethane (1,2-DCA)-contaminated groundwater have been evaluated through an in situ bioaugmentation test at an industrial site (Belgium). The migration of strain DCA1 was monitored from an injection well toward a monitoring well, and the effect of the imposed groundwater flow on its distribution was assessed by means of transport model MOCDENS3D. The results of the real-time PCR (16S rRNA gene) quantification downstream from the injection point were used to evaluate the bacterial distribution pattern simulated by MOCDENS3D. In the injection well, the 1,2-DCA concentration in the groundwater decreased from 939.8 to 0.9 microM in a 35 day time interval and in the presence of a sodium lactate solution. Moreover, analyses from the monitoring well showed that the cells were still active after transport through the aquifer, although biodegradation occurred to a lesser extent. This study showed that strain DCA1 can be successfully applied for the removal of 1,2-DCA under field conditions and that its limited retardation offers perspectives for large-scale cleanup processes of industrial sites.
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Affiliation(s)
- Ann Maes
- Laboratory of Microbial Ecology and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
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Kassenga GR, Pardue JH. Effect of competitive terminal electron acceptor processes on dechlorination of cis-1,2-dichloroethene and 1,2-dichloroethane in constructed wetland soils. FEMS Microbiol Ecol 2006; 57:311-23. [PMID: 16867148 DOI: 10.1111/j.1574-6941.2006.00115.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Thermodynamic calculations were coupled with time-series measurements of chemical species (parent and daughter chlorinated solvents, H(2), sulfite, sulfate and methane) to predict the anaerobic transformation of cis-1,2-dichloroethene (cis-1,2-DCE) and 1,2-dichloroethane (1,2-DCA) in constructed wetland soil microcosms inoculated with a dehalorespiring culture. For cis-1,2-DCE, dechlorination occurred simultaneously with sulfite and sulfate reduction but competitive exclusion of methanogenesis was observed due to the rapid H(2) drawdown by the dehalorespiring bacteria. Rates of cis-1,2-DCE dechlorination decreased proportionally to the free energy yield of the competing electron acceptor and proportionally to the rate of H(2) drawdown, suggesting that H(2) competition between dehalorespirers and other populations was occurring, affecting the dechlorination rate. For 1,2-DCA, dechlorination occurred simultaneously with methanogenesis and sulfate reduction but occurred only after sulfite was completely depleted. Rates of 1,2-DCA dechlorination were unaffected by the presence of competing electron-accepting processes. The absence of a low H(2) threshold suggests that 1,2-DCA dechlorination is a cometabolic transformation, occurring at a higher H(2) threshold, despite the high free energy yields available for dehalorespiration of 1,2-DCA. We demonstrate the utility of kinetic and thermodynamic calculations to understand the complex, H(2)-utilizing reactions occurring in the wetland bed and their effect on rates of dechlorination of priority pollutants.
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Affiliation(s)
- Gabriel R Kassenga
- Department of Civil & Environmental Engineering, Louisiana State University, Baton Rouge, LA 70803, USA
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Bae HS, Moe WM, Yan J, Tiago I, da Costa MS, Rainey FA. Propionicicella superfundia gen. nov., sp. nov., a chlorosolvent-tolerant propionate-forming, facultative anaerobic bacterium isolated from contaminated groundwater. Syst Appl Microbiol 2006; 29:404-13. [PMID: 16338112 DOI: 10.1016/j.syapm.2005.11.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Indexed: 10/25/2022]
Abstract
A novel strain, designated as BL-10(T), was characterized using a polyphasic approach after isolation from groundwater contaminated by a mixture of chlorosolvents that included 1,1,2-trichloroethane, 1,2-dichloroethane, and vinyl chloride. Stain BL-10(T) is a facultatively anaerobic bacterium able to ferment glucose to form propionate, acetate, formate, lactate, and succinate. Fermentation occurred in the presence of 1,2-dichloroethane and 1,1,2-trichloroethane at concentrations to at least 9.8 and 5.9 mM, respectively. Cells are Gram-positive, rod-shaped, non-motile, and do not form spores. Oxidase and catalase are not produced and nitrate reduction did not occur in PYG medium. Menaquinone MK-9 is the predominant respiratory quinone and meso-diaminopimelic acid is present in the cell wall peptidoglycan layer. Major cellular fatty acids are C(15:0), iso C(16:0), and anteiso C(15:0). Genomic DNA G + C content is 69.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed strain BL-10(T) to fall within the radiation of genera Propionicimonas and Micropruina. On the basis of the results obtained in this study, it is proposed that strain BL-10(T) should be classified as a novel taxon, for which the name Propionicicella superfundia gen. nov., sp. nov. is proposed. The type strain of Propionicicella superfundia is BL-10(T) (=ATCC BAA-1218(T), =LMG 23096(T)).
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Affiliation(s)
- Hee-Sung Bae
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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Dinglasan-Panlilio MJ, Dworatzek S, Mabury S, Edwards E. Microbial oxidation of 1,2-dichloroethane under anoxic conditions with nitrate as electron acceptor in mixed and pure cultures. FEMS Microbiol Ecol 2006; 56:355-64. [PMID: 16689868 DOI: 10.1111/j.1574-6941.2006.00077.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Many organisms have been found to readily oxidize the prevalent contaminant 1,2-dichloroethane (1,2-DCA) to CO2 under aerobic conditions. Some organisms have also been isolated that can reduce 1,2-DCA to ethene via dihaloelimination under anaerobic, fermentative conditions. However, none have been described that can metabolize 1,2-DCA under anoxic, nitrate-reducing conditions. In microcosms prepared from aquifer material and groundwater samples from a contaminated site in eastern Louisiana, USA, 1,2-DCA was observed to degrade with nitrate as the terminal electron acceptor. Nitrate-dependent enrichment cultures were developed from these microcosms that sustained rapid 1,2-DCA degradation rates of up to 500 microM day(-1). This degradation was tightly coupled to complete reduction of nitrate via nitrite to nitrogen gas. A novel 1,2-DCA-degrading organism belonging to the Betaproteobacteria (affiliated with the genus Thauera) was isolated from this enrichment culture. However, degradation rates were much slower in cultures of the isolate than observed in the parent mixed culture. Complete mineralization of 1,2-DCA to CO2 was linked to cell growth and to nitrate reduction in both enrichment and isolated cultures. Monochloroacetate, a putative metabolite of 1,2-DCA degradation, could also be mineralized by these cultures.
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Olaniran AO, Pillay D, Pillay B. Biostimulation and bioaugmentation enhances aerobic biodegradation of dichloroethenes. Chemosphere 2006; 63:600-8. [PMID: 16213559 DOI: 10.1016/j.chemosphere.2005.08.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 08/08/2005] [Accepted: 08/12/2005] [Indexed: 05/04/2023]
Abstract
The accumulation of dichloroethenes (DCEs) as dominant products of microbial reductive dechlorination activity in soil and water represent a significant obstacle to the application of bioremediation as a remedial option for chloroethenes in many contaminated systems. In this study, the effects of biostimulation and/or bioaugmentation on the biodegradation of cis- and trans-DCE in soil and water samples collected from contaminated sites in South Africa were evaluated in order to determine the possible bioremediation option for these compounds in the contaminated sites. Results from this study indicate that cis- and trans-DCE were readily degraded to varying degrees by natural microbial populations in all the soil and water samples tested, with up to 44% of cis-DCE and 41% of trans-DCE degraded in the untreated soil and water samples in two weeks. The degradation rate constants ranged significantly (P<0.05) between 0.0938 and 0.560 wk(-1) and 0.182 and 0.401 wk(-1), for cis- and trans-DCE, respectively, for the various treatments employed. A combination of biostimulation and bioaugmentation significantly increased the biodegradation of both compounds within two weeks; 14% for cis-DCE and 18% for trans-DCE degradation, above those observed in untreated soil and water samples. These findings support the use of a combination of biostimulation and bioaugmentation for the efficient biodegradation of these compounds in contaminated soil and water. In addition, the results clearly demonstrate that while naturally occurring microorganisms are capable of aerobic biodegradation of cis- and trans-DCE, biotransformation may be affected by several factors, including isomer structure, soil type, and the amount of nutrients available in the water and soil.
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Affiliation(s)
- Ademola O Olaniran
- Department of Microbiology, Faculty of Science and Agriculture, University of KwaZulu-Natal (Westville Campus), Private Bag X54001, Durban 4000, South Africa.
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Abstract
Mixed anaerobic microbial subcultures enriched from a multilayered aquifer at a former chlorinated solvent disposal facility in West Louisiana were examined to determine the organism(s) involved in the dechlorination of the toxic compounds 1,2-dichloroethane (1,2-DCA) and 1,1,2-trichloroethane (1,1,2-TCA) to ethene. Sequences phylogenetically related to Dehalobacter and Dehalococcoides, two genera of anaerobic bacteria that are known to respire with chlorinated ethenes, were detected through cloning of bacterial 16S rRNA genes. Denaturing gradient gel electrophoresis analysis of 16S rRNA gene fragments after starvation and subsequent reamendment of culture with 1,2-DCA showed that the Dehalobacter sp. grew during the dichloroelimination of 1,2-DCA to ethene, implicating this organism in degradation of 1,2-DCA in these cultures. Species-specific real-time quantitative PCR was further used to monitor proliferation of Dehalobacter and Dehalococcoides during the degradation of chlorinated ethanes and showed that in fact both microorganisms grew simultaneously during the degradation of 1,2-DCA. Conversely, Dehalobacter grew during the dichloroelimination of 1,1,2-TCA to vinyl chloride (VC) but not during the subsequent reductive dechlorination of VC to ethene, whereas Dehalococcoides grew only during the reductive dechlorination of VC but not during the dichloroelimination of 1,1,2-TCA. This demonstrated that in mixed cultures containing multiple dechlorinating microorganisms, these organisms can have either competitive or complementary dechlorination activities, depending on the chloro-organic substrate.
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Affiliation(s)
- Ariel Grostern
- Department of Botany, University of Toronto, 200 College St., Toronto, ON M5S 3E5, Canada
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Koutinas M, Martin J, Peeva LG, Mantalaris A, Livingston AG. An oil-absorber-bioscrubber system to stabilize biotreatment of pollutants present in waste gas. Fluctuating loads of 1,2-dichloroethane. Environ Sci Technol 2006; 40:595-602. [PMID: 16468408 DOI: 10.1021/es051073r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Biotreatment technologies offer a cost-effective and efficient method for dealing with point-source releases of solvents. However, a major problem hampering these technologies is the fluctuating pollutant loads, which is especially critical for inhibitory pollutants. Provision of biotreatment systems able to cope with this problem is a significant technological and environmental challenge. This study investigates the potential for an absorber to act as buffer for shock loadings of inhibitory pollutants in waste-gas streams undergoing biological treatment. 1,2-Dichloroethane (DCE) was used as an example of a toxic and inhibitory organic pollutant. The stability of a combined oil-absorber-bioscrubber (OAB) system was compared to that of a bioscrubber only (BO) system when each was subjected to shock loads of DCE. The BO system was inoculated with Xanthobacter autotrophicus strain GJ10 and was submitted to sharp, sequential pulses in DCE inlet load, which caused system instability. Complete inhibition of the BO process occurred for a 3 h DCE pulse, leading to 9125 g of DCE m(-3)bioscrubber total organic discharged (TODDCE). Following the pulse, fluorescence in situ hybridization (FISH) showed that the active strain GJ10 was effectively washed-out. In contrast, the performance of the OAB system was stable during DCE shock loads. The carbon dioxide production remained stable, and low levels of effluent DCE and total organic carbon concentrations were found. For the 3 h pulse TODDCE was only 173 g of DCE m(-3)bioscrubber, and FISH indicated that the GJ10 strain remained active. We conclude that the OAB system offers an effective solution to the biological treatment of waste-gas containing fluctuating pollutant concentrations.
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Affiliation(s)
- Michalis Koutinas
- Department of Chemical Engineering and Chemical Technology, Imperial College London, United Kingdom
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Abstract
Microbial reductive dechlorination of [1,2-14C]trichloroethene to [14C]cis-dichloroethene and [14C]vinyl chloride was observed at 4 degrees C in anoxic microcosms prepared with cold temperature-adapted aquifer and river sediments from Alaska. Microbial anaerobic oxidation of [1,2-14C]cis-dichloroethene and [1,2-14C]vinyl chloride to 14CO2 also was observed under these conditions.
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Affiliation(s)
- P M Bradley
- U.S. Geological Survey, 720 Gracern Rd., Suite 129, Columbia, SC 29210, USA.
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Marzorati M, Borin S, Brusetti L, Daffonchio D, Marsilli C, Carpani G, de Ferra F. Response of 1,2-dichloroethane-adapted microbial communities to ex-situ biostimulation of polluted groundwater. Biodegradation 2005; 17:143-58. [PMID: 16565809 DOI: 10.1007/s10532-005-9004-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2005] [Indexed: 11/29/2022]
Abstract
The microbial community of a groundwater system contaminated by 1,2-dichloroethane (1,2-DCA), a toxic and persistent chlorinated hydrocarbon, has been investigated for its response to biostimulation finalized to 1,2-DCA removal by reductive dehalogenation. The microbial population profile of samples from different wells in the aquifer and from microcosms enriched in the laboratory with different organic electron donors was analyzed by ARISA (Amplified Ribosomal Intergenic Spacer Analysis) and DGGE (Denaturing Gradient Gel Electrophoresis) of 16S rRNA genes. 1,2-DCA was completely removed with release of ethene from most of the microcosms supplemented with lactate, acetate plus formate, while cheese whey supported 1,2-DCA dehalogenation only after a lag period. Microbial species richness deduced from ARISA profiles of the microbial community before and after electron donor amendments indicated that the response of the community to biostimulation was heterogeneous and depended on the well from which groundwater was sampled. Sequencing of 16S rRNA genes separated by DGGE indicated the presence of bacteria previously associated with soils and groundwater polluted by halogenated hydrocarbons or present in consortia active in the removal of these compounds. A PCR assay specific for Desulfitobacterium sp. showed the enrichment of this genus in some of the microcosms. The dehalogenation potential of the microbial community was confirmed by the amplification of dehalogenase-related sequences from the most active microcosms. Cloning and sequencing of PCR products indicated the presence in the metagenome of the bacterial community of a new dehalogenase potentially involved in 1,2-DCA reductive dechlorination.
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Affiliation(s)
- Massimo Marzorati
- DISTAM, Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università degli Studi di Milano, via Celoria 2, 20133 Milan, Italy
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Soriano A, Silla E, Tuñón I, Ruiz-López MF. Dynamic and electrostatic effects in enzymatic processes. An analysis of the nucleophilic substitution reaction in haloalkane dehalogenase. J Am Chem Soc 2005; 127:1946-57. [PMID: 15701029 DOI: 10.1021/ja046553h] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present an analysis of rare event trajectories for the nucleophilic displacement of a chloride anion of 1,2-dichloroethane by a carboxylate group in haloalkane dehalogenase from Xanthobacterautotrophicus (DhlA) and in aqueous solution. Differences in the transmission coefficient are rationalized on the basis of the electrostatic coupling between the chemical system and the environment. Detailed analysis of the reactive trajectories reveals that the evolution of the hydrogen bond interactions established between the substrate and the environment present significant differences in aqueous solution and in the enzyme. The structure of the enzymatic active site provides a more adequate interaction pattern for the reaction progress.
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Affiliation(s)
- Alejandro Soriano
- Departament de Química Física/IcMol, Universidad de Valencia, 46100 Burjasot, Valencia, Spain
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