101
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Atashgahi S, Liebensteiner MG, Janssen DB, Smidt H, Stams AJM, Sipkema D. Microbial Synthesis and Transformation of Inorganic and Organic Chlorine Compounds. Front Microbiol 2018; 9:3079. [PMID: 30619161 PMCID: PMC6299022 DOI: 10.3389/fmicb.2018.03079] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 11/29/2018] [Indexed: 12/26/2022] Open
Abstract
Organic and inorganic chlorine compounds are formed by a broad range of natural geochemical, photochemical and biological processes. In addition, chlorine compounds are produced in large quantities for industrial, agricultural and pharmaceutical purposes, which has led to widespread environmental pollution. Abiotic transformations and microbial metabolism of inorganic and organic chlorine compounds combined with human activities constitute the chlorine cycle on Earth. Naturally occurring organochlorines compounds are synthesized and transformed by diverse groups of (micro)organisms in the presence or absence of oxygen. In turn, anthropogenic chlorine contaminants may be degraded under natural or stimulated conditions. Here, we review phylogeny, biochemistry and ecology of microorganisms mediating chlorination and dechlorination processes. In addition, the co-occurrence and potential interdependency of catabolic and anabolic transformations of natural and synthetic chlorine compounds are discussed for selected microorganisms and particular ecosystems.
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Affiliation(s)
- Siavash Atashgahi
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | | | - Dick B. Janssen
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Alfons J. M. Stams
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
- Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Detmer Sipkema
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
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102
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Terán JE, Zambrano CH, Mora JR, Rincón L, Torres FJ. Theoretical investigation of the mechanism for the reductive dehalogenation of methyl halides mediated by the Co I-based compounds cobalamin and cobaloxime. J Mol Model 2018; 24:316. [PMID: 30338391 DOI: 10.1007/s00894-018-3844-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 09/17/2018] [Indexed: 11/30/2022]
Abstract
Theoretical calculations focusing on the cleavage of the C-X bond in methyl halides (CH3X; X = Cl, Br, I) as mediated by CoI-based systems have been carried out using the hybrid functional ωB97-XD together with the basis set 6-311++G(2d,2p). A total of seven CoI-based compounds were evaluated: cob[I]alamin (CoICbl) in its base-on form and cobaloxime (CoICbx) with either no ligand or different ligands (either pyridine (PYR), tributylphosphine (TBP), dimethyl sulfide (DMS), cyclohexylisocyanide (CI), or 5,6-dimethylbenzimidazole (DMB)) at the lower axial position. For the large CoICbl system, an ONIOM scheme was employed, where the high layer was described at the DFT level and the low layer was computed using the semi-empirical method PM6. A full DFT model was employed for the CoICbx cases. An SN2-like mechanism was evaluated in all cases. The intrinsic reaction coordinate profiles suggested early transition states with activation energies of ≈ 12 kcal/mol, ≈ 10 kcal/mol, and ≈ 5 kcal/mol for C-Cl, C-Br, and C-I cleavage, respectively, which is consistent with the leaving group abilities of these halides. The evolutions of the atomic charges in and the bond orders of Co-C and C-X were computed, and the results confirmed the existence of early transition states (δBav≈ 40%), where the polarization Cδ+-Xδ- (%Ev ≈ 43%) is the determining factor in the reaction process. Finally, a comparison of all the determined parameters showed that the reaction in the DMB-CoICbx system resembles the process that occurs in the larger CoICbl, suggesting that the former system could be a reliable model for the study of reductive dehalogenation mediated by vitamin B12, which is key to the anaerobic microbiological treatment of halocarbon contaminants.
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Affiliation(s)
- Julio E Terán
- Universidad San Francisco de Quito, Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador.,Universidad San Francisco de Quito, Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador
| | - Cesar H Zambrano
- Universidad San Francisco de Quito, Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador.,Universidad San Francisco de Quito, Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador
| | - Jose R Mora
- Universidad San Francisco de Quito, Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador. .,Universidad San Francisco de Quito, Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador.
| | - L Rincón
- Universidad San Francisco de Quito, Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador.,Universidad San Francisco de Quito, Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador
| | - F J Torres
- Universidad San Francisco de Quito, Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador.,Universidad San Francisco de Quito, Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador
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103
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Chen F, Li Z, Yang J, Liang B, Huang C, Cai W, Nan J, Wang A. Electron Fluxes in Biocathode Bioelectrochemical Systems Performing Dechlorination of Chlorinated Aliphatic Hydrocarbons. Front Microbiol 2018; 9:2306. [PMID: 30323798 PMCID: PMC6173060 DOI: 10.3389/fmicb.2018.02306] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 09/10/2018] [Indexed: 11/13/2022] Open
Abstract
Bioelectrochemical systems (BESs) are regarded as a promising approach for the enhanced dechlorination of chlorinated aliphatic hydrocarbons (CAHs). However, the electron distribution and transfer considering dechlorination, methanogenesis, and other bioprocesses in these systems are little understood. This study investigated the electron fluxes in biocathode BES performing dechlorination of three typical CAHs, 1,1,2,2-tetrachloroethene (PCE), 1,1,2-trichloroethene (TCE) and 1,2-dichloroethane (1,2-DCA). Anaerobic sludge was inoculated to cathode and biocathode was acclimated by the direct acclimation and selection. The constructed biocathode at −0.26 V had significantly higher dechlorination efficiency (E24h > 99.0%) than the opened circuit (E24h of 17.2–27.5%) and abiotic cathode (E24h of 5.5–10.8%), respectively. Cyclic voltammetry analysis demonstrated the enhanced cathodic current and the positive shift of onset potential in the cathodic biofilm. Under autotrophic conditions with electrons from the cathode as sole energy source (columbic efficiencies of 80.4–90.0%) and bicarbonate as sole carbon source, CAHs dechlorination efficiencies were still maintained at 85.0 ± 2.0%, 91.4 ± 1.8%, and 84.9 ± 3.1% for PCE, TCE, and 1,2-DCA, respectively. Cis-1,2-dichloroethene was the final product for PCE and TCE, while 1,2-DCA went through a different dechlorination pathway with the non-toxic ethene as the final metabolite. Methane was the main by-product of the heterotrophic biocathode, and methane production could be enhanced to some extent by electrochemical stimulation. The various electron fluxes originating from the cathode and oxidation of organic substrates might be responsible for the enhanced CAHs dechlorination, while methane generation and bacterial growth would probably reduce the fraction of electrons provided for CAH dechlorination. The study deals with the dechlorination and competitive bioprocesses in CAH-dechlorinating biocathodes with a focus on electron fluxes.
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Affiliation(s)
- Fan Chen
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
| | - Zhiling Li
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
| | - Jiaqi Yang
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
| | - Bin Liang
- Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Cong Huang
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
| | - Weiwei Cai
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
| | - Jun Nan
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, China
| | - Aijie Wang
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin, China.,Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
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104
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Molenda O, Tang S, Lomheim L, Gautam VK, Lemak S, Yakunin AF, Maxwell KL, Edwards EA. Extrachromosomal circular elements targeted by CRISPR-Cas in Dehalococcoides mccartyi are linked to mobilization of reductive dehalogenase genes. ISME JOURNAL 2018; 13:24-38. [PMID: 30104577 DOI: 10.1038/s41396-018-0254-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/13/2018] [Accepted: 06/19/2018] [Indexed: 01/12/2023]
Abstract
Dehalococcoides mccartyi are obligate organohalide-respiring bacteria that play an important detoxifying role in the environment. They have small genomes (~1.4 Mb) with a core region interrupted by two high plasticity regions (HPRs) containing dozens of genes encoding reductive dehalogenases involved in organohalide respiration. The genomes of eight new strains of D. mccartyi were closed from metagenomic data from a related set of enrichment cultures, bringing the total number of genomes to 24. Two of the newly sequenced strains and three previously sequenced strains contain CRISPR-Cas systems. These D. mccartyi CRISPR-Cas systems were found to primarily target prophages and genomic islands. The genomic islands were identified either as integrated into D. mccartyi genomes or as circular extrachromosomal elements. We observed active circularization of the integrated genomic island containing vcrABC operon encoding the dehalogenase (VcrA) responsible for the transformation of vinyl chloride to non-toxic ethene. We interrogated archived DNA from established enrichment cultures and found that the CRISPR array acquired three new spacers in 11 years. These data provide a glimpse into dynamic processes operating on the genomes distinct to D. mccartyi strains found in enrichment cultures and provide the first insights into possible mechanisms of lateral DNA exchange in D. mccartyi.
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Affiliation(s)
- Olivia Molenda
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | | | - Line Lomheim
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Vasu K Gautam
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Sofia Lemak
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Alexander F Yakunin
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Karen L Maxwell
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Elizabeth A Edwards
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada. .,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.
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105
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Wang S, Qiu L, Liu X, Xu G, Siegert M, Lu Q, Juneau P, Yu L, Liang D, He Z, Qiu R. Electron transport chains in organohalide-respiring bacteria and bioremediation implications. Biotechnol Adv 2018; 36:1194-1206. [DOI: 10.1016/j.biotechadv.2018.03.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 03/22/2018] [Accepted: 03/23/2018] [Indexed: 01/08/2023]
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106
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Zhao S, Rogers MJ, Ding C, He J. Reductive Debromination of Polybrominated Diphenyl Ethers - Microbes, Processes and Dehalogenases. Front Microbiol 2018; 9:1292. [PMID: 29971048 PMCID: PMC6018424 DOI: 10.3389/fmicb.2018.01292] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 05/28/2018] [Indexed: 02/03/2023] Open
Abstract
Extensive utilization of polybrominated diphenyl ethers (PBDEs) as flame retardants since the 1960s in a variety of commercial products has resulted in ubiquitous environmental distribution of commercial PBDE mixtures. Dangers posed to biological populations became apparent after the discovery of elevated levels of PBDEs in biota, most notably in human breast milk and tissues. Environmental persistence of PBDEs results in significant transboundary displacement, threatening fragile ecosystems globally. Despite efforts to curtail usage of PBDEs, public concern remains about the effects of legacy PBDEs contamination and continued discharge of PBDEs in regions lacking restrictions on usage and manufacture. Among available technologies for remediation of PBDEs such as ex-situ soil washing, electrokinetic degradation, and biodegradation, this review focuses on bioremediation by microbes under anaerobic conditions. Bioremediation is generally preferred as it is less disruptive to contaminated ecosystems, is cost-effective, and can be implemented at sites that may be inaccessible to more traditional ex-situ methods. The aims of this review are to (1) summarize current knowledge of anaerobic microbes that debrominate PBDEs and their associated synergistic partnerships with non-dehalogenating microbes; (2) explore current understandings of the metabolic reductive debromination of PBDE congeners; (3) discuss recent discoveries on dehalogenase genes involved in debromination of PBDEs.
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Affiliation(s)
- Siyan Zhao
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
| | - Matthew J Rogers
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
| | - Chang Ding
- Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Jianzhong He
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore, Singapore
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107
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Seidel K, Kühnert J, Adrian L. The Complexome of Dehalococcoides mccartyi Reveals Its Organohalide Respiration-Complex Is Modular. Front Microbiol 2018; 9:1130. [PMID: 29946299 PMCID: PMC6005880 DOI: 10.3389/fmicb.2018.01130] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 05/14/2018] [Indexed: 11/30/2022] Open
Abstract
Dehalococcoides mccartyi strain CBDB1 is a slow growing strictly anaerobic microorganism dependent on halogenated compounds as terminal electron acceptor for anaerobic respiration. Indications have been described that the membrane-bound proteinaceous organohalide respiration complex of strain CBDB1 is functional without quinone-mediated electron transfer. We here study this multi-subunit protein complex in depth in regard to participating protein subunits and interactions between the subunits using blue native gel electrophoresis coupled to mass spectrometric label-free protein quantification. Applying three different solubilization modes to detach the respiration complex from the membrane we describe different solubilization snapshots of the organohalide respiration complex. The results demonstrate the existence of a two-subunit hydrogenase module loosely binding to the rest of the complex, tight binding of the subunit HupX to OmeA and OmeB, predicted to be the two subunits of a molybdopterin-binding redox subcomplex, to form a second module, and the presence of two distinct reductive dehalogenase module variants with different sizes. In our data we obtained biochemical evidence for the specificity between a reductive dehalogenase RdhA (CbdbA80) and its membrane anchor protein RdhB (CbdbB3). We also observed weak interactions between the reductive dehalogenase and the hydrogenase module suggesting a not yet recognized contact surface between these two modules. Especially an interaction between the two integral membrane subunits OmeB and RdhB seems to promote the integrity of the complex. With the different solubilization strengths we observe successive disintegration of the complex into its subunits. The observed architecture would allow the association of different reductive dehalogenase modules RdhA/RdhB with the other two protein complex modules when the strain is growing on different electron acceptors. In the search for other respiratory complexes in strain CBDB1 the remarkable result is not the detection of a standard ATPase but the absence of any other abundant membrane complex although an 11-subunit version of complex I (Nuo) is encoded in the genome.
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Affiliation(s)
- Katja Seidel
- Department Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Joana Kühnert
- Department Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Lorenz Adrian
- Department Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany.,Chair of Geobiotechnology, Technische Universität Berlin, Berlin, Germany
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108
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Mattes TE, Ewald JM, Liang Y, Martinez A, Awad A, Richards P, Hornbuckle KC, Schnoor JL. PCB dechlorination hotspots and reductive dehalogenase genes in sediments from a contaminated wastewater lagoon. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:16376-16388. [PMID: 28803405 PMCID: PMC6206866 DOI: 10.1007/s11356-017-9872-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 07/31/2017] [Indexed: 05/04/2023]
Abstract
Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants that are distributed worldwide. Although industrial PCB production has stopped, legacy contamination can be traced to several different commercial mixtures (e.g., Aroclors in the USA). Despite their persistence, PCBs are subject to naturally occurring biodegradation processes, although the microbes and enzymes involved are poorly understood. The biodegradation potential of PCB-contaminated sediments in a wastewater lagoon located in Virginia (USA) was studied. Total PCB concentrations in sediments ranged from 6.34 to 12,700 mg/kg. PCB congener profiles in sediment sample were similar to Aroclor 1248; however, PCB congener profiles at several locations showed evidence of dechlorination. The sediment microbial community structure varied among samples but was dominated by Proteobacteria and Firmicutes. The relative abundance of putative dechlorinating Chloroflexi (including Dehalococcoides sp.) was 0.01-0.19% among the sediment samples, with Dehalococcoides sp. representing 0.6-14.8% of this group. Other possible PCB dechlorinators present included the Clostridia and the Geobacteraceae. A PCR survey for potential PCB reductive dehalogenase genes (RDases) yielded 11 sequences related to RDase genes in PCB-respiring Dehalococcoides mccartyi strain CG5 and PCB-dechlorinating D. mccartyi strain CBDB1. This is the first study to retrieve potential PCB RDase genes from unenriched PCB-contaminated sediments.
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Affiliation(s)
- Timothy E Mattes
- Department of Civil and Environmental Engineering, University of Iowa, 4105 Seamans Center, Iowa City, IA, 52242, USA.
| | - Jessica M Ewald
- Department of Civil and Environmental Engineering, University of Iowa, 4105 Seamans Center, Iowa City, IA, 52242, USA
| | - Yi Liang
- Department of Civil and Environmental Engineering, University of Iowa, 4105 Seamans Center, Iowa City, IA, 52242, USA
| | - Andres Martinez
- Department of Civil and Environmental Engineering, University of Iowa, 4105 Seamans Center, Iowa City, IA, 52242, USA
| | - Andrew Awad
- Department of Civil and Environmental Engineering, University of Iowa, 4105 Seamans Center, Iowa City, IA, 52242, USA
| | - Patrick Richards
- Department of Civil and Environmental Engineering, University of Iowa, 4105 Seamans Center, Iowa City, IA, 52242, USA
| | - Keri C Hornbuckle
- Department of Civil and Environmental Engineering, University of Iowa, 4105 Seamans Center, Iowa City, IA, 52242, USA
| | - Jerald L Schnoor
- Department of Civil and Environmental Engineering, University of Iowa, 4105 Seamans Center, Iowa City, IA, 52242, USA
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109
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Pérez-de-Mora A, Lacourt A, McMaster ML, Liang X, Dworatzek SM, Edwards EA. Chlorinated Electron Acceptor Abundance Drives Selection of Dehalococcoides mccartyi ( D. mccartyi) Strains in Dechlorinating Enrichment Cultures and Groundwater Environments. Front Microbiol 2018; 9:812. [PMID: 29867784 PMCID: PMC5968391 DOI: 10.3389/fmicb.2018.00812] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/10/2018] [Indexed: 01/23/2023] Open
Abstract
Dehalococcoides mccartyi (D. mccartyi) strains differ primarily from one another by the number and identity of the reductive dehalogenase homologous catalytic subunit A (rdhA) genes within their respective genomes. While multiple rdhA genes have been sequenced, the activity of the corresponding proteins has been identified in only a few cases. Examples include the enzymes whose substrates are groundwater contaminants such as trichloroethene (TCE), cis-dichloroethene (cDCE) and vinyl chloride (VC). The associated rdhA genes, namely tceA, bvcA, and vcrA, along with the D. mccartyi 16S rRNA gene are often used as biomarkers of growth in field samples. In this study, we monitored an additional 12 uncharacterized rdhA sequences identified in the metagenome in the mixed D. mccartyi-containing culture KB-1 to monitor population shifts in more detail. Quantitative PCR (qPCR) assays were developed for 15 D. mccartyi rdhA genes and used to measure population diversity in 11 different sub-cultures of KB-1, each enriched on different chlorinated ethenes and ethanes. The proportion of rdhA gene copies relative to D. mccartyi 16S rRNA gene copies revealed the presence of multiple distinct D. mccartyi strains in each culture, many more than the two strains inferred from 16S rRNA analysis. The specific electron acceptor amended to each culture had a major influence on the distribution of D. mccartyi strains and their associated rdhA genes. We also surveyed the abundance of rdhA genes in samples from two bioaugmented field sites (Canada and United Kingdom). Growth of the dominant D. mccartyi strain in KB-1 was detected at the United Kingdom site. At both field sites, the measurement of relative rdhA abundances revealed D. mccartyi population shifts over time as dechlorination progressed from TCE through cDCE to VC and ethene. These shifts indicate a selective pressure of the most abundant chlorinated electron acceptor, as was also observed in lab cultures. These results also suggest that reductive dechlorination at contaminated sites is brought about by multiple strains of D. mccartyi whether or not the site is bioaugmented. Understanding the driving forces behind D. mccartyi population selection and activity is improving predictability of remediation performance at chlorinated solvent contaminated sites.
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Affiliation(s)
- Alfredo Pérez-de-Mora
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, ON, Canada.,Research Unit Analytical Biogeochemistry, Department of Environmental Sciences, Helmholtz Zentrum München, Neuherberg, Germany
| | - Anna Lacourt
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | | | - Xiaoming Liang
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | | | - Elizabeth A Edwards
- Department of Chemical Engineering & Applied Chemistry, University of Toronto, Toronto, ON, Canada
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110
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Wang YF, Zhu HW, Wang Y, Zhang XL, Tam NFY. Diversity and Dynamics of Microbial Community Structure in Different Mangrove, Marine and Freshwater Sediments During Anaerobic Debromination of PBDEs. Front Microbiol 2018; 9:952. [PMID: 29867858 PMCID: PMC5962692 DOI: 10.3389/fmicb.2018.00952] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/24/2018] [Indexed: 01/11/2023] Open
Abstract
Little is known about the diversity and succession of indigenous microbial community during debromination of polybrominated diphenyl ethers (PBDEs). This study examined the diversity and dynamics of microbial community structure in eight saline (mangrove and marine) and freshwater sediment microcosms exhibiting different debrominating capabilities for hexa-BDE 153, a common congener in sediments, using terminal restriction fragment length polymorphism (T-RFLP) and clone library analyses. The results showed that microbial community structure greatly differed between the saline and freshwater microcosms, likely leading to distinct variations in their debrominating capabilities and pathways. Higher relative abundances of Chloroflexi and Deltaproteobacteria succeed by Alphaproteobacteria and Betaproteobacteria were detected in the two mangrove microcosms with the fastest debrominating capabilities mainly via para pathway, respectively; the dominance of Alphaproteobacteria resulted in less accumulation of tetra-BDEs and more complete debromination of lower brominated congeners (from di- to tetra-BDEs). Meanwhile, the shifts in both microbial community structure and PBDE profiles were relatively small in the less efficient freshwater microcosms, with relatively more ortho and meta brominated products of BDE-153 resulted. Coincidently, one of the freshwater microcosms showed sudden increases of Chloroflexi and Deltaproteobacteria by the end of incubation, which synchronized with the increase in the removal rate of BDE-153. The significant relationship between microbial community structure and PBDEs was confirmed by redundancy analysis (18.7% of total variance explained, P = 0.002). However, the relative abundance of the well-known dechlorinator Dehalococcoides showed no clear correlation with the debrominating capability across different microcosms. These findings shed light in the significance of microbial community network in different saline environments on enhancement of PBDE intrinsic debromination.
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Affiliation(s)
- Ya Fen Wang
- Laboratory of Basin Hydrology and Wetland Eco-restoration, School of Environmental Studies, China University of Geosciences, Wuhan, China.,Department of Biology and Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Hao Wen Zhu
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Ying Wang
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Xiang Ling Zhang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, China
| | - Nora Fung Yee Tam
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong.,State Key Laboratory in Marine Pollution, City University of Hong Kong, Kowloon Tong, Hong Kong
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111
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El-Sayed WS. Characterization of a Highly Enriched Microbial Consortium Reductively Dechlorinating 2,3-Dichlorophenol and 2,4,6-Trichlorophenol and the Corresponding cprA Genes from River Sediment. Pol J Microbiol 2018; 65:341-352. [PMID: 29334051 DOI: 10.5604/17331331.1215613] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Anaerobic reductive dechlorination of 2,3-dichlorophenol (2,3DCP) and 2,4,6-trichlorophenol (2,4,6TCP) was investigated in microcosms from River Nile sediment. A stable sediment-free anaerobic microbial consortium reductively dechlorinating 2,3DCP and 2,4,6TCP was established. Defined sediment-free cultures showing stable dechlorination were restricted to ortho chlorine when enriched with hydrogen as the electron donor, acetate as the carbon source, and either 2,3-DCP or 2,4,6-TCP as electron acceptors. When acetate, formate, or pyruvate were used as electron donors, dechlorination activity was lost. Only lactate can replace dihydrogen as an electron donor. However, the dechlorination potential was decreased after successive transfers. To reveal chlororespiring species, the microbial community structure of chlorophenol-reductive dechlorinating enrichment cultures was analyzed by PCR-denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments. Eight dominant bacteria were detected in the dechlorinating microcosms including members of the genera Citrobacter, Geobacter, Pseudomonas, Desulfitobacterium, Desulfovibrio and Clostridium. Highly enriched dechlorinating cultures were dominated by four bacterial species belonging to the genera Pseudomonas, Desulfitobacterium, and Clostridium. Desulfitobacterium represented the major fraction in DGGE profiles indicating its importance in dechlorination activity, which was further confirmed by its absence resulting in complete loss of dechlorination. Reductive dechlorination was confirmed by the stoichiometric dechlorination of 2,3DCP and 2,4,6TCP to metabolites with less chloride groups and by the detection of chlorophenol RD cprA gene fragments in dechlorinating cultures. PCR amplified cprA gene fragments were cloned and sequenced and found to cluster with the cprA/pceA type genes of Dehalobacter restrictus.
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Affiliation(s)
- Wael S El-Sayed
- Biology Department, Faculty of Science, Taibah University, Almadinah Almunawarah, KSA; Microbiology Department, Faculty of Science, Ain Shams University, Cairo, Egypt
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Türkowsky D, Esken J, Goris T, Schubert T, Diekert G, Jehmlich N, von Bergen M. A Retentive Memory of Tetrachloroethene Respiration in Sulfurospirillum halorespirans - involved Proteins and a possible link to Acetylation of a Two-Component Regulatory System. J Proteomics 2018; 181:36-46. [PMID: 29617628 DOI: 10.1016/j.jprot.2018.03.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/08/2018] [Accepted: 03/27/2018] [Indexed: 10/17/2022]
Abstract
Organohalide respiration (OHR), comprising the reductive dehalogenation of halogenated organic compounds, is subject to a unique memory effect and long-term transcriptional downregulation of the involved genes in Sulfurospirillum multivorans. Gene expression ceases slowly over approximately 100 generations in the absence of tetrachloroethene (PCE). However, the molecular mechanisms of this regulation process are not understood. We show here that Sulfurospirillum halorespirans undergoes the same type of regulation when cultivated without chlorinated ethenes for a long period of time. In addition, we compared the proteomes of S. halorespirans cells cultivated in the presence of PCE with those of cells long- and short-term cultivated with nitrate as the sole electron acceptor. Important OHR-related proteins previously unidentified in S. multivorans include a histidine kinase, a putative quinol dehydrogenase membrane protein, and a PCE-induced porin. Since for some regulatory proteins a posttranslational regulation of activity by lysine acetylations is known, we also analyzed the acetylome of S. halorespirans, revealing that 32% of the proteome was acetylated in at least one condition. The data indicate that the response regulator and the histidine kinase of a two-component system most probably involved in induction of PCE respiration are highly acetylated during short-term cultivation with nitrate in the absence of PCE. SIGNIFICANCE The so far unique long-term downregulation of organohalide respiration is now identified in a second species suggesting a broader distribution of this regulatory phenomenon. An improved protein extraction method allowed the identification of proteins most probably involved in transcriptional regulation of OHR in Sulfurospirillum spp. Our data indicate that acetylations of regulatory proteins are involved in this extreme, sustained standby-mode of metabolic enzymes in the absence of a substrate. This first published acetylome of Epsilonproteobacteria might help to study other ecologically or medically important species of this clade.
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Affiliation(s)
- Dominique Türkowsky
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Jens Esken
- Department of Applied and Ecological Microbiology, Institute of Microbiology, Friedrich Schiller University, Philosophenweg 12, 07743 Jena, Germany
| | - Tobias Goris
- Department of Applied and Ecological Microbiology, Institute of Microbiology, Friedrich Schiller University, Philosophenweg 12, 07743 Jena, Germany
| | - Torsten Schubert
- Department of Applied and Ecological Microbiology, Institute of Microbiology, Friedrich Schiller University, Philosophenweg 12, 07743 Jena, Germany
| | - Gabriele Diekert
- Department of Applied and Ecological Microbiology, Institute of Microbiology, Friedrich Schiller University, Philosophenweg 12, 07743 Jena, Germany
| | - Nico Jehmlich
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, 04318 Leipzig, Germany; Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Brüderstraße, 34, Germany.
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113
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Schubert T, Adrian L, Sawers RG, Diekert G. Organohalide respiratory chains: composition, topology and key enzymes. FEMS Microbiol Ecol 2018; 94:4923014. [DOI: 10.1093/femsec/fiy035] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 02/28/2018] [Indexed: 02/07/2023] Open
Affiliation(s)
- Torsten Schubert
- Department of Applied and Ecological Microbiology, Institute of Microbiology, Friedrich Schiller University, Philosophenweg 12, D-07743 Jena, Germany
| | - Lorenz Adrian
- Department Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, D-04318 Leipzig, Germany
- Department of Geobiotechnology, Technische Universität Berlin, Ackerstraße 74, D-13355 Berlin, Germany
| | - R Gary Sawers
- Institute of Biology/Microbiology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Straße 3, D-06120 Halle (Saale), Germany
| | - Gabriele Diekert
- Department of Applied and Ecological Microbiology, Institute of Microbiology, Friedrich Schiller University, Philosophenweg 12, D-07743 Jena, Germany
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114
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Harrison BK, Myrbo A, Flood BE, Bailey JV. Abrupt burial imparts persistent changes to the bacterial diversity of turbidite-associated sediment profiles. GEOBIOLOGY 2018; 16:190-202. [PMID: 29350440 DOI: 10.1111/gbi.12271] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 11/09/2017] [Indexed: 06/07/2023]
Abstract
The emplacement of subaqueous gravity-driven sediment flows imposes a significant physical and geochemical impact on underlying sediment and microbial communities. Although previous studies have established lasting mineralogical and biological signatures of turbidite deposition, the response of bacteria and archaea within and beneath debris flows remains poorly constrained. Both bacterial cells associated with the underlying sediment and those attached to allochthonous material must respond to substantially altered environmental conditions and selective pressures. As a consequence, turbidites and underlying sediments provide an exceptional opportunity to examine (i) the microbial community response to rapid sedimentation and (ii) the preservation and identification of displaced micro-organisms. We collected Illumina MiSeq sequence libraries across turbidite boundaries at ~26 cm sediment depth in La Jolla Canyon off the coast of California, and at ~50 cm depth in meromictic Twin Lake, Hennepin County, MN. 16S rRNA gene signatures of relict and active bacterial populations exhibit persistent differences attributable to turbidite deposition. In particular, both the marine and lacustrine turbidite boundaries are sharply demarcated by the abundance and diversity of Chloroflexi, suggesting a characteristic sensitivity to sediment disturbance history or to differences in organic substrates across turbidite profiles. Variations in the abundance of putative dissimilatory sulfate-reducing Deltaproteobacteria across the buried La Jolla Canyon sediment-water interface reflect turbidite-induced changes to the geochemical environment. Species-level distinctions within the Deltaproteobacteria clearly conform to the sedimentological boundary, suggesting a continuing impact of genetic inheritance distinguishable from broader trends attributable to selective pressure. Abrupt, <1-cm scale changes in bacterial diversity across the Twin Lake turbidite contact are consistent with previous studies showing that relict DNA signatures attributable to sediment transport may be more easily preserved in low-energy, anoxic environments. This work raises the possibility that deep subsurface microbial communities may inherit variations in microbial diversity from sediment flow and deformation events.
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Affiliation(s)
- B K Harrison
- Department of Earth and Atmospheric Sciences, Central Michigan University, Mt. Pleasant, MI, USA
- Department of Earth Sciences, University of Minnesota, Twin Cities, Minneapolis, MN, USA
| | - A Myrbo
- LacCore/CSDCO, Limnological Research Center, Department of Earth Sciences, University of Minnesota, Twin Cities, Minneapolis, MN, USA
| | - B E Flood
- Department of Earth Sciences, University of Minnesota, Twin Cities, Minneapolis, MN, USA
| | - J V Bailey
- Department of Earth Sciences, University of Minnesota, Twin Cities, Minneapolis, MN, USA
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115
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Puentes Jácome LA, Edwards EA. A switch of chlorinated substrate causes emergence of a previously undetected native Dehalobacter population in an established Dehalococcoides-dominated chloroethene-dechlorinating enrichment culture. FEMS Microbiol Ecol 2018; 93:4569067. [PMID: 29088371 DOI: 10.1093/femsec/fix141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 10/26/2017] [Indexed: 01/08/2023] Open
Abstract
Chlorobenzenes are soil and groundwater pollutants of concern that can be reductively dehalogenated by organohalide-respiring bacteria from the genera Dehalococcoides and Dehalobacter. The bioaugmentation culture KB-1® harbours Dehalococcoides mccartyi spp. that reductively dehalogenate trichloroethene to ethene. It contains more than 30 reductive dehalogenase genes; some of them are highly similar to genes found in the chlorobenzene-respiring Dehalococcoides mccartyi strain CBDB1. We explored the chlorobenzene dehalogenation capability of the KB-1 enrichment culture using 1,2,4-trichlorobenzene (1,2,4-TCB). We achieved adaptation of KB-1 to 1,2,4-TCB that is dehalogenated to a mixture of dichlorobenzenes, and subsequently to monochlorobenzene and benzene. Surprisingly, a native Dehalobacter population, and not a Dehalococcoides population, couples the dechlorination of 1,2,4-TCB to growth achieving an average yield of 1.1 ± 0.6 × 1013 cells per mole of Cl- released. Interestingly, the dechlorination of 1,2,4-TCB occurs alongside the complete dechlorination of trichloroethene to ethene in cultures fed both electron acceptors. Dehalobacter was not previously identified as a major player in KB-1, but its ecological niche was favoured by the introduction of 1,2,4-TCB. Based on 16S rRNA phylogeny, Dehalobacter populations seem to cluster into specialised clades, and are likely undergoing substrate specialisation as a strategy to reduce competition for electron acceptors.
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Affiliation(s)
- Luz A Puentes Jácome
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5S 3E5, Canada
| | - Elizabeth A Edwards
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5S 3E5, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 1A1, Canada
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116
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Matturro B, Frascadore E, Rossetti S. High-throughput sequencing revealed novel Dehalococcoidia in dechlorinating microbial enrichments from PCB-contaminated marine sediments. FEMS Microbiol Ecol 2018; 93:4443194. [PMID: 29040506 DOI: 10.1093/femsec/fix134] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 10/10/2017] [Indexed: 01/07/2023] Open
Abstract
In this study, six PCE-to-ethene dechlorinating cultures, fed with a fermentable substrate (lactate) or hydrogen as electron donor, were obtained from PCB and PCE dechlorinating microcosms constructed with PCB-contaminated marine sediments. A novel Chloroflexi member (OTU-DIS1) affiliated to Dehalococcoidales Incertae Sedis, only distantly related to known dechlorinating bacteria, dominated the enrichment cultures (up to 86% of total OTUs). Sulfate-, thiosulfate- and sulfur-reducing bacteria affiliated to genera Desulfobacter, Dethiosulfatibacter and Desulfuromusa were also found to lesser extent. Remarkably, tceA, vcrA and the bifunctional PCE/PCB dehalogenase genes pcbA1, pcbA4 and pcbA5 were found in all dechlorinating microbial enrichments indicating the coexistence of different Dehalococcoides mccartyi strains. The reductive dechlorination rate in each culture remained unvaried over long-term operation (≈ 30 months) and ranged between 0.85 and 0.97 mmol Cl-1 released L-1 d-1 in the lactate-fed microbial enrichments and between 0.66 and 0.85 mmol Cl-1 released L-1 d-1 in the H2-fed microbial enrichments. Overall, this study highlights the presence of yet unexplored biodiversity in PCBs contaminated marine sediments and indicates these environments as promising sources of novel organohalide-respiring bacteria.
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Affiliation(s)
- Bruna Matturro
- Water Research Institute, IRSA-CNR, Via Salaria km 29,300, 00015 Monterotondo (RM), Italy
| | - Emanuela Frascadore
- Water Research Institute, IRSA-CNR, Via Salaria km 29,300, 00015 Monterotondo (RM), Italy
| | - Simona Rossetti
- Water Research Institute, IRSA-CNR, Via Salaria km 29,300, 00015 Monterotondo (RM), Italy
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117
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Zhang S, Adrian L, Schüürmann G. Interaction Mode and Regioselectivity in Vitamin B 12-Dependent Dehalogenation of Aryl Halides by Dehalococcoides mccartyi Strain CBDB1. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:1834-1843. [PMID: 29283566 DOI: 10.1021/acs.est.7b04278] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The bacterium Dehalococcoides, strain CBDB1, transforms aromatic halides through reductive dehalogenation. So far, however, the structures of its vitamin B12-containing dehalogenases are unknown, hampering clarification of the catalytic mechanism and substrate specificity as basis for targeted remediation strategies. This study employs a quantum chemical donor-acceptor approach for the Co(I)-substrate electron transfer. Computational characterization of the substrate electron affinity at carbon-halogen bonds enables discriminating aromatic halides ready for dehalogenation by strain CBDB1 (active substrates) from nondehalogenated (inactive) counterparts with 92% accuracy, covering 86 of 93 bromobenzenes, chlorobenzenes, chlorophenols, chloroanilines, polychlorinated biphenyls, and dibenzo-p-dioxins. Moreover, experimental regioselectivity is predicted with 78% accuracy by a site-specific parameter encoding the overlap potential between the Co(I) HOMO (highest occupied molecular orbital) and the lowest-energy unoccupied sigma-symmetry substrate MO (σ*), and the observed dehalogenation pathways are rationalized with a success rate of 81%. Molecular orbital analysis reveals that the most reactive unoccupied sigma-symmetry orbital of carbon-attached halogen X (σC-X*) mediates its reductive cleavage. The discussion includes predictions for untested substrates, thus providing opportunities for targeted experimental investigations. Overall, the presently introduced orbital interaction model supports the view that with bacterial strain CBDB1, an inner-sphere electron transfer from the supernucleophile B12 Co(I) to the halogen substituent of the aromatic halide is likely to represent the rate-determining step of the reductive dehalogenation.
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Affiliation(s)
- Shangwei Zhang
- UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research , Permoserstraße 15, 04318 Leipzig, Germany
- Technical University Bergakademie Freiberg , Institute for Organic Chemistry, Leipziger Straße 29, 09596 Freiberg, German y
| | - Lorenz Adrian
- UFZ Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research , Permoserstraße 15, 04318 Leipzig, Germany
- Technische Universität Berlin , Chair of Geobiotechnology, Ackerstraße 76, 13355 Berlin, Germany
| | - Gerrit Schüürmann
- UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research , Permoserstraße 15, 04318 Leipzig, Germany
- Technical University Bergakademie Freiberg , Institute for Organic Chemistry, Leipziger Straße 29, 09596 Freiberg, German y
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118
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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 RESEARCH 2018; 128:362-382. [PMID: 29126033 DOI: 10.1016/j.watres.2017.10.059] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [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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119
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Tiedt O, Mergelsberg M, Eisenreich W, Boll M. Promiscuous Defluorinating Enoyl-CoA Hydratases/Hydrolases Allow for Complete Anaerobic Degradation of 2-Fluorobenzoate. Front Microbiol 2017; 8:2579. [PMID: 29312255 PMCID: PMC5742626 DOI: 10.3389/fmicb.2017.02579] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/11/2017] [Indexed: 01/20/2023] Open
Abstract
Biodegradation of the environmentally hazardous fluoroaromatics has mainly been associated with oxygenase-dependent defluorination reactions. Only very recently a novel mode of oxygen-independent defluorination was identified for the complete degradation of para-substituted fluoroaromatics in the denitrifying Thauera aromatica: a promiscuous class I benzoyl-coenzyme A (BzCoA) reductase (BCR) catalyzed the ATP-dependent defluorination of 4-F-BzCoA to BzCoA. Here, we studied the unknown enzymatic defluorination during the complete degradation of 2-F-benzoate to CO2 and HF. We demonstrate that after activation of 2-F-benzoate by a promiscuous AMP-forming benzoate-CoA ligase, the 2-F-BzCoA formed is subsequently dearomatized by BCR to a mixture of 2-F- and 6-F-cyclohexa-1,5-diene-1-carboxyl-CoA (2-F-/6-F-1,5-dienoyl-CoA). This finding indicates that BCR is not involved in C–F-bond cleavage during growth with 2-F-benzoate. Instead, we identified defluorination of the two isomers by enoyl-CoA hydratases/hydrolases involved in down-stream reactions of the BzCoA degradation pathway. (i) The 1,5-dienoyl-CoA hydratase hydrated the F-1,5-dienoyl-CoA isomers to a mixture of the stable 2-F-6-OH-1-enoyl-CoA and the unstable α-fluorohydrin 6-F-6-OH-1-enoyl-CoA; the latter spontaneously decomposed to HF and 6-oxo-cyclohex-1-enoyl-CoA (6-oxo-1-enoyl-CoA), a common intermediate of the BzCoA degradation pathway. (ii) 6-Oxo-1-enoyl-CoA hydrolase/hydratase catalyzed the defluorination of 2-F-6-OH-1-enoyl-CoA to 2-oxo-6-OH-1-enoyl-CoA and HF again via water addition to an F-enoyl-CoA functionality. Based on these in vitro results, we demonstrate a previously overseen capability of 2-F-benzoate degradation for many but not all tested facultatively and obligately anaerobic bacteria that degrade aromatic compounds via the BzCoA degradation pathway. In conclusion, the newly identified enzymatic defluorination by enoyl-CoA hydratases via α-fluorohydrin formation represents an abundant, physiologically relevant principle of enzymatic defluorination.
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Affiliation(s)
- Oliver Tiedt
- Faculty of Biology - Microbiology, Institute of Biology II, University of Freiburg, Freiburg, Germany
| | - Mario Mergelsberg
- Faculty of Biology - Microbiology, Institute of Biology II, University of Freiburg, Freiburg, Germany
| | | | - Matthias Boll
- Faculty of Biology - Microbiology, Institute of Biology II, University of Freiburg, Freiburg, Germany
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120
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Atashgahi S, Häggblom MM, Smidt H. Organohalide respiration in pristine environments: implications for the natural halogen cycle. Environ Microbiol 2017; 20:934-948. [PMID: 29215190 DOI: 10.1111/1462-2920.14016] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 11/29/2017] [Accepted: 12/01/2017] [Indexed: 11/29/2022]
Abstract
Halogenated organic compounds, also termed organohalogens, were initially considered to be of almost exclusively anthropogenic origin. However, over 5000 naturally synthesized organohalogens are known today. This has also fuelled the hypothesis that the natural and ancient origin of organohalogens could have primed development of metabolic machineries for their degradation, especially in microorganisms. Among these, a special group of anaerobic microorganisms was discovered that could conserve energy by reducing organohalogens as terminal electron acceptor in a process termed organohalide respiration. Originally discovered in a quest for biodegradation of anthropogenic organohalogens, these organohalide-respiring bacteria (OHRB) were soon found to reside in pristine environments, such as the deep subseafloor and Arctic tundra soil with limited/no connections to anthropogenic activities. As such, accumulating evidence suggests an important role of OHRB in local natural halogen cycles, presumably taking advantage of natural organohalogens. In this minireview, we integrate current knowledge regarding the natural origin and occurrence of industrially important organohalogens and the evolution and spread of OHRB, and describe potential implications for natural halogen and carbon cycles.
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Affiliation(s)
- Siavash Atashgahi
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Wageningen 6708 WE, The Netherlands
| | - Max M Häggblom
- Department of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Wageningen 6708 WE, The Netherlands
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121
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Franke S, Lihl C, Renpenning J, Elsner M, Nijenhuis I. Triple-element compound-specific stable isotope analysis of 1,2-dichloroethane for characterization of the underlying dehalogenation reaction in two Dehalococcoides mccartyi strains. FEMS Microbiol Ecol 2017; 93:4561051. [DOI: 10.1093/femsec/fix137] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 10/17/2017] [Indexed: 11/12/2022] Open
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122
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Xu Y, He Y, Tang X, Brookes PC, Xu J. Reconstruction of microbial community structures as evidences for soil redox coupled reductive dechlorination of PCP in a mangrove soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 596-597:147-157. [PMID: 28431359 DOI: 10.1016/j.scitotenv.2017.04.073] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 04/07/2017] [Accepted: 04/09/2017] [Indexed: 05/26/2023]
Abstract
The aim was to investigate the influence of pentachlorophenol (PCP) on the soil microbial communities and the coupled mechanism between PCP reductive dechlorination and soil redox under anaerobic condition. Accordingly, a slurry incubation experiment was carried out in which bacterial and archaeal communities were detected by MiSeq amplicon sequencing. The original microbial community balance was gradually disrupted and new microbial structure was reconstructed subsequently through self-regulation and acclimation during PCP transformation, coupling with the changes of soil biogeochemical redox dynamics. The phylum Bacteroidetes predominated during the earlier PCP dechlorination period and then was progressively replaced by Proteobacteria and Firmicutes groups when PCP was mostly transformed into 2,3,4,5-TeCP and 3,4,5-TCP. Heatmap and hierarchical cluster analysis revealed the Clostridium-like, Geobacter-like and Dehalococcoides-like organisms enriched concurrently during PCP reductive dechlorination processes. The relative abundance changes of the redox-active microorganisms, together with their relevance to the corresponding biogeochemical redox processes, showed that PCP dechlorination, Fe(III) and SO42- reduction, as well as methanogenesis were coupled terminal electron accepting processes. The combined analysis of the microbial function, the affinity for substrates (H2 and acetate) and the sensitivity for PCP toxicity by microorganisms might explain why electron transport chain has changed in soil biogeochemical redox process. Our study offers a comprehensive description of the impact of PCP on the soil microbial community structures, which could be very useful for understanding the regulation of soil nutrient and energy transfer during biogeochemical cycling processes in soils with significant inputs of exogenous pollutants.
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Affiliation(s)
- Yan Xu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China
| | - Yan He
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China.
| | - Xianjin Tang
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China
| | - Philip C Brookes
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China
| | - Jianming Xu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China
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Kruse T, Goris T, Maillard J, Woyke T, Lechner U, de Vos W, Smidt H. Comparative genomics of the genus Desulfitobacterium. FEMS Microbiol Ecol 2017; 93:4443196. [DOI: 10.1093/femsec/fix135] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 10/10/2017] [Indexed: 02/03/2023] Open
Affiliation(s)
- Thomas Kruse
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Tobias Goris
- Department of Applied and Ecological Microbiology, Friedrich-Schiller-University Jena, Philosophenweg 12, 07743 Jena, Germany
| | - Julien Maillard
- Laboratory for Environmental Biotechnology, ENAC-IIE-LBE, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015 Lausanne, Switzerland
| | - Tanja Woyke
- U.S. Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Ute Lechner
- Institute of Biology/Microbiology, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 3, Halle 06120, Germany
| | - Willem de Vos
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
- Research Programme Unit Immunobiology, Department of Bacteriology and Immunology, Helsinki University, P.O. Box 21, 00014 Helsinki, Finland
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
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Liu J, Lopez N, Ahn Y, Goldberg T, Bromberg Y, Kerkhof LJ, Häggblom MM. Novel reductive dehalogenases from the marine sponge associated bacterium Desulfoluna spongiiphila. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:537-549. [PMID: 28618195 DOI: 10.1111/1758-2229.12556] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 05/08/2017] [Accepted: 06/03/2017] [Indexed: 06/07/2023]
Abstract
Desulfoluna spongiiphila strain AA1 is an organohalide respiring bacterium, isolated from the marine sponge Aplysina aerophoba, that can use brominated and iodinated phenols, in addition to sulfate and thiosulfate as terminal electron acceptors. The genome of Desulfoluna spongiiphila strain AA1 is approximately 6.5 Mb. Three putative reductive dehalogenase (rdhA) genes involved in respiratory metabolism of organohalides were identified within the sequence. Conserved motifs found in respiratory reductive dehalogenases (a twin arginine translocation signal sequence and two iron-sulfur clusters) were present in all three putative AA1 rdhA genes. Transcription of one of the three rdhA genes was significantly upregulated during respiration of 2,6-dibromophenol and sponge extracts. Strain AA1 appears to have the ability to synthesize cobalamin, the key cofactor of most characterized reductive dehalogenase enzymes. The genome contains genes involved in cobalamin synthesis and uptake and can grow without cobalamin supplementation. Identification of this target gene associated with debromination lays the foundation for understanding how dehalogenating bacteria control the fate of organohalide compounds in sponges and their role in a symbiotic organobromine cycle. In the sponge environment, D. spongiiphila strain AA1 may thus take advantage of both brominated compounds and sulfate as electron acceptors for respiration.
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Affiliation(s)
- Jie Liu
- Departments of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Nora Lopez
- Departments of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
- Marine and Coastal Sciences, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Youngbeom Ahn
- Departments of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Tatyana Goldberg
- Department for Bioinformatics and Computational Biology, Technical University Munich, Garching, 85748, Germany
| | - Yana Bromberg
- Departments of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Lee J Kerkhof
- Marine and Coastal Sciences, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
| | - Max M Häggblom
- Departments of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
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125
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Kunze C, Diekert G, Schubert T. Subtle changes in the active site architecture untangled overlapping substrate ranges and mechanistic differences of two reductive dehalogenases. FEBS J 2017; 284:3520-3535. [DOI: 10.1111/febs.14258] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/20/2017] [Accepted: 08/30/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Cindy Kunze
- Department of Applied and Ecological Microbiology; Institute of Microbiology; Friedrich Schiller University; Jena Germany
| | - Gabriele Diekert
- Department of Applied and Ecological Microbiology; Institute of Microbiology; Friedrich Schiller University; Jena Germany
| | - Torsten Schubert
- Department of Applied and Ecological Microbiology; Institute of Microbiology; Friedrich Schiller University; Jena Germany
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Identification of Multiple Dehalogenase Genes Involved in Tetrachloroethene-to-Ethene Dechlorination in a Dehalococcoides-Dominated Enrichment Culture. BIOMED RESEARCH INTERNATIONAL 2017; 2017:9191086. [PMID: 28894752 PMCID: PMC5574268 DOI: 10.1155/2017/9191086] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 07/03/2017] [Indexed: 11/17/2022]
Abstract
Chloroethenes (CEs) are widespread groundwater toxicants that are reductively dechlorinated to nontoxic ethene (ETH) by members of Dehalococcoides. This study established a Dehalococcoides-dominated enrichment culture (designated “YN3”) that dechlorinates tetrachloroethene (PCE) to ETH with high dechlorination activity, that is, complete dechlorination of 800 μM PCE to ETH within 14 days in the presence of Dehalococcoides species at 5.7 ± 1.9 × 107 copies of 16S rRNA gene/mL. The metagenome of YN3 harbored 18 rdhA genes (designated YN3rdhA1–18) encoding the catalytic subunit of reductive dehalogenase (RdhA), four of which were suggested to be involved in PCE-to-ETH dechlorination based on significant increases in their transcription in response to CE addition. The predicted proteins for two of these four genes, YN3RdhA8 and YN3RdhA16, showed 94% and 97% of amino acid similarity with PceA and VcrA, which are well known to dechlorinate PCE to trichloroethene (TCE) and TCE to ETH, respectively. The other two rdhAs, YN3rdhA6 and YN3rdhA12, which were never proved as rdhA for CEs, showed particularly high transcription upon addition of vinyl chloride (VC), with 75 ± 38 and 16 ± 8.6 mRNA copies per gene, respectively, suggesting their possible functions as novel VC-reductive dehalogenases. Moreover, metagenome data indicated the presence of three coexisting bacterial species, including novel species of the genus Bacteroides, which might promote CE dechlorination by Dehalococcoides.
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127
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Yang Y, Higgins SA, Yan J, Şimşir B, Chourey K, Iyer R, Hettich RL, Baldwin B, Ogles DM, Löffler FE. Grape pomace compost harbors organohalide-respiring Dehalogenimonas species with novel reductive dehalogenase genes. ISME JOURNAL 2017; 11:2767-2780. [PMID: 28809851 DOI: 10.1038/ismej.2017.127] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 06/12/2017] [Accepted: 06/16/2017] [Indexed: 12/15/2022]
Abstract
Organohalide-respiring bacteria have key roles in the natural chlorine cycle; however, most of the current knowledge is based on cultures from contaminated environments. We demonstrate that grape pomace compost without prior exposure to chlorinated solvents harbors a Dehalogenimonas (Dhgm) species capable of using chlorinated ethenes, including the human carcinogen and common groundwater pollutant vinyl chloride (VC) as electron acceptors. Grape pomace microcosms and derived solid-free enrichment cultures were able to dechlorinate trichloroethene (TCE) to less chlorinated daughter products including ethene. 16S rRNA gene amplicon and qPCR analyses revealed a predominance of Dhgm sequences, but Dehalococcoides mccartyi (Dhc) biomarker genes were not detected. The enumeration of Dhgm 16S rRNA genes demonstrated VC-dependent growth, and 6.55±0.64 × 108 cells were measured per μmole of chloride released. Metagenome sequencing enabled the assembly of a Dhgm draft genome, and 52 putative reductive dehalogenase (RDase) genes were identified. Proteomic workflows identified a putative VC RDase with 49 and 56.1% amino acid similarity to the known VC RDases VcrA and BvcA, respectively. A survey of 1,173 groundwater samples collected from 111 chlorinated solvent-contaminated sites in the United States and Australia revealed that Dhgm 16S rRNA genes were frequently detected and outnumbered Dhc in 65% of the samples. Dhgm are likely greater contributors to reductive dechlorination of chlorinated solvents in contaminated aquifers than is currently recognized, and non-polluted environments represent sources of organohalide-respiring bacteria with novel RDase genes.
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Affiliation(s)
- Yi Yang
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN, USA.,Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN, USA.,Joint Institute for Biological Sciences (JIBS), Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Steven A Higgins
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN, USA.,Joint Institute for Biological Sciences (JIBS), Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Department of Microbiology, University of Tennessee, Knoxville, TN, USA.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Jun Yan
- Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN, USA.,Joint Institute for Biological Sciences (JIBS), Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Department of Microbiology, University of Tennessee, Knoxville, TN, USA.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, China
| | - Burcu Şimşir
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN, USA
| | - Karuna Chourey
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Ramsunder Iyer
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Genome Science and Technology, University of Tennessee, Knoxville, TN, USA
| | - Robert L Hettich
- Joint Institute for Biological Sciences (JIBS), Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Genome Science and Technology, University of Tennessee, Knoxville, TN, USA
| | | | | | - Frank E Löffler
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN, USA.,Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN, USA.,Joint Institute for Biological Sciences (JIBS), Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Department of Microbiology, University of Tennessee, Knoxville, TN, USA.,Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.,Genome Science and Technology, University of Tennessee, Knoxville, TN, USA
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128
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Yang Y, Cápiro NL, Marcet TF, Yan J, Pennell KD, Löffler FE. Organohalide Respiration with Chlorinated Ethenes under Low pH Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:8579-8588. [PMID: 28665587 DOI: 10.1021/acs.est.7b01510] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Bioremediation at chlorinated solvent sites often leads to groundwater acidification due to electron donor fermentation and enhanced dechlorination activity. The microbial reductive dechlorination process is robust at circumneutral pH, but activity declines at groundwater pH values below 6.0. Consistent with this observation, the activity of tetrachloroethene (PCE) dechlorinating cultures declined at pH 6.0 and was not sustained in pH 5.5 medium, with one notable exception. Sulfurospirillum multivorans dechlorinated PCE to cis-1,2-dichloroethene (cDCE) in pH 5.5 medium and maintained this activity upon repeated transfers. Microcosms established with soil and aquifer materials from five distinct locations dechlorinated PCE-to-ethene at pH 5.5 and pH 7.2. Dechlorination to ethene was maintained following repeated transfers at pH 7.2, but no ethene was produced at pH 5.5, and only the transfer cultures derived from the Axton Cross Superfund (ACS) microcosms sustained PCE dechlorination to cDCE as a final product. 16S rRNA gene amplicon sequencing of pH 7.2 and pH 5.5 ACS enrichments revealed distinct microbial communities, with the dominant dechlorinator being Dehalococcoides in pH 7.2 and Sulfurospirillum in pH 5.5 cultures. PCE-to-trichloroethene- (TCE-) and PCE-to-cDCE-dechlorinating isolates obtained from the ACS pH 5.5 enrichment shared 98.6%, and 98.5% 16S rRNA gene sequence similarities to Sulfurospirillum multivorans. These findings imply that sustained Dehalococcoides activity cannot be expected in low pH (i.e., ≤ 5.5) groundwater, and organohalide-respiring Sulfurospirillum spp. are key contributors to in situ PCE reductive dechlorination under low pH conditions.
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Affiliation(s)
| | - Natalie L Cápiro
- Department of Civil and Environmental Engineering, Tufts University , Medford, Massachusetts 02155, United States
| | - Tyler F Marcet
- Department of Civil and Environmental Engineering, Tufts University , Medford, Massachusetts 02155, United States
| | | | - Kurt D Pennell
- Department of Civil and Environmental Engineering, Tufts University , Medford, Massachusetts 02155, United States
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129
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Cobamide-mediated enzymatic reductive dehalogenation via long-range electron transfer. Nat Commun 2017; 8:15858. [PMID: 28671181 PMCID: PMC5500849 DOI: 10.1038/ncomms15858] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/03/2017] [Indexed: 12/18/2022] Open
Abstract
The capacity of metal-containing porphyrinoids to mediate reductive dehalogenation is implemented in cobamide-containing reductive dehalogenases (RDases), which serve as terminal reductases in organohalide-respiring microbes. RDases allow for the exploitation of halogenated compounds as electron acceptors. Their reaction mechanism is under debate. Here we report on substrate–enzyme interactions in a tetrachloroethene RDase (PceA) that also converts aryl halides. The shape of PceA’s highly apolar active site directs binding of bromophenols at some distance from the cobalt and with the hydroxyl substituent towards the metal. A close cobalt–substrate interaction is not observed by electron paramagnetic resonance spectroscopy. Nonetheless, a halogen substituent para to the hydroxyl group is reductively eliminated and the path of the leaving halide is traced in the structure. Based on these findings, an enzymatic mechanism relying on a long-range electron transfer is concluded, which is without parallel in vitamin B12-dependent biochemistry and represents an effective mode of RDase catalysis. Cobalamin-containing reductive dehalogenases from organohalide-respiring bacteria play a key role in the degradation of halogenated organic compounds. Here the authors proposed a catalytic mechanism for dehalogenation that relies on a long-range electron transfer from the cobalt in the centre of the enzyme’s cofactor to the substrate.
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130
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Affiliation(s)
- Maeva Fincker
- Department of Civil and Environmental Engineering and Department of Chemical Engineering, Stanford University, Stanford, California 94305;,
| | - Alfred M. Spormann
- Department of Civil and Environmental Engineering and Department of Chemical Engineering, Stanford University, Stanford, California 94305;,
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131
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Dolinová I, Štrojsová M, Černík M, Němeček J, Macháčková J, Ševců A. Microbial degradation of chloroethenes: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:13262-13283. [PMID: 28378313 DOI: 10.1007/s11356-017-8867-y] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 03/17/2017] [Indexed: 05/28/2023]
Abstract
Contamination by chloroethenes has a severe negative effect on both the environment and human health. This has prompted intensive remediation activity in recent years, along with research into the efficacy of natural microbial communities for degrading toxic chloroethenes into less harmful compounds. Microbial degradation of chloroethenes can take place either through anaerobic organohalide respiration, where chloroethenes serve as electron acceptors; anaerobic and aerobic metabolic degradation, where chloroethenes are used as electron donors; or anaerobic and aerobic co-metabolic degradation, with chloroethene degradation occurring as a by-product during microbial metabolism of other growth substrates, without energy or carbon benefit. Recent research has focused on optimising these natural processes to serve as effective bioremediation technologies, with particular emphasis on (a) the diversity and role of bacterial groups involved in dechlorination microbial processes, and (b) detection of bacterial enzymes and genes connected with dehalogenation activity. In this review, we summarise the different mechanisms of chloroethene bacterial degradation suitable for bioremediation and provide a list of dechlorinating bacteria. We also provide an up-to-date summary of primers available for detecting functional genes in anaerobic and aerobic bacteria degrading chloroethenes metabolically or co-metabolically.
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Affiliation(s)
- Iva Dolinová
- Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic
- Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic
| | - Martina Štrojsová
- Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic
| | - Miroslav Černík
- Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic
- Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic
| | - Jan Němeček
- Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic
| | - Jiřina Macháčková
- Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic
| | - Alena Ševců
- Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic.
- Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Studentská 2, 461 17, Liberec, Czech Republic.
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132
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Agarwal V, Miles ZD, Winter JM, Eustáquio AS, El Gamal AA, Moore BS. Enzymatic Halogenation and Dehalogenation Reactions: Pervasive and Mechanistically Diverse. Chem Rev 2017; 117:5619-5674. [PMID: 28106994 PMCID: PMC5575885 DOI: 10.1021/acs.chemrev.6b00571] [Citation(s) in RCA: 249] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Naturally produced halogenated compounds are ubiquitous across all domains of life where they perform a multitude of biological functions and adopt a diversity of chemical structures. Accordingly, a diverse collection of enzyme catalysts to install and remove halogens from organic scaffolds has evolved in nature. Accounting for the different chemical properties of the four halogen atoms (fluorine, chlorine, bromine, and iodine) and the diversity and chemical reactivity of their organic substrates, enzymes performing biosynthetic and degradative halogenation chemistry utilize numerous mechanistic strategies involving oxidation, reduction, and substitution. Biosynthetic halogenation reactions range from simple aromatic substitutions to stereoselective C-H functionalizations on remote carbon centers and can initiate the formation of simple to complex ring structures. Dehalogenating enzymes, on the other hand, are best known for removing halogen atoms from man-made organohalogens, yet also function naturally, albeit rarely, in metabolic pathways. This review details the scope and mechanism of nature's halogenation and dehalogenation enzymatic strategies, highlights gaps in our understanding, and posits where new advances in the field might arise in the near future.
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Affiliation(s)
- Vinayak Agarwal
- Center for Oceans and Human Health, Scripps Institution of Oceanography, University of California, San Diego
| | - Zachary D. Miles
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego
| | | | - Alessandra S. Eustáquio
- College of Pharmacy, Department of Medicinal Chemistry & Pharmacognosy and Center for Biomolecular Sciences, University of Illinois at Chicago
| | - Abrahim A. El Gamal
- Center for Oceans and Human Health, Scripps Institution of Oceanography, University of California, San Diego
| | - Bradley S. Moore
- Center for Oceans and Human Health, Scripps Institution of Oceanography, University of California, San Diego
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego
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133
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Microbial reductive dehalogenation of trihalomethanes by a Dehalobacter-containing co-culture. Appl Microbiol Biotechnol 2017; 101:5481-5492. [DOI: 10.1007/s00253-017-8236-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/06/2017] [Accepted: 03/09/2017] [Indexed: 10/19/2022]
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134
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Zhang S, Wondrousch D, Cooper M, Zinder SH, Schüürmann G, Adrian L. Anaerobic Dehalogenation of Chloroanilines by Dehalococcoides mccartyi Strain CBDB1 and Dehalobacter Strain 14DCB1 via Different Pathways as Related to Molecular Electronic Structure. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:3714-3724. [PMID: 28233989 DOI: 10.1021/acs.est.6b05730] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Dehalococcoides mccartyi strain CBDB1 and Dehalobacter strain 14DCB1 are organohalide-respiring microbes of the phyla Chloroflexi and Firmicutes, respectively. Here, we report the transformation of chloroanilines by these two bacterial strains via dissimilar dehalogenation pathways and discuss the underlying mechanism with quantum chemically calculated net atomic charges of the substrate Cl, H, and C atoms. Strain CBDB1 preferentially removed Cl doubly flanked by two Cl or by one Cl and NH2, whereas strain 14DCB1 preferentially dechlorinated Cl that has an ortho H. For the CBDB1-mediated dechlorination, comparative analysis with Hirshfeld charges shows that the least-negative Cl discriminates active from nonactive substrates in 14 out of 15 cases and may represent the preferred site of primary attack through cob(I)alamin. For the latter trend, three of seven active substrates provide strong evidence, with partial support from three of the remaining four substrates. Regarding strain 14DCB1, the most positive carbon-attached H atom discriminates active from nonactive chloroanilines in again 14 out of 15 cases. Here, regioselectivity is governed for 10 of the 11 active substrates by the most positive H attached to the highest-charge (most positive or least negative) aromatic C carrying the Cl to be removed. These findings suggest the aromatic ring H as primary site of attack through the supernucleophile Co(I), converting an initial H bond to a full electron transfer as start of the reductive dehalogenation. For both mechanisms, one- and two-electron transfer to Cl (strain CBDB1) or H (strain 14DCB1) are compatible with the presently available data. Computational chemistry research into reaction intermediates and pathways may further aid in understanding the bacterial reductive dehalogenation at the molecular level.
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Affiliation(s)
- Shangwei Zhang
- Institute for Organic Chemistry, Technical University Bergakademie Freiberg , Leipziger Straße 29, 09596 Freiberg, Germany
| | - Dominik Wondrousch
- Institute for Organic Chemistry, Technical University Bergakademie Freiberg , Leipziger Straße 29, 09596 Freiberg, Germany
| | | | - Stephen H Zinder
- Department of Microbiology, Cornell University , Ithaca, New York 14853, United States
| | - Gerrit Schüürmann
- Institute for Organic Chemistry, Technical University Bergakademie Freiberg , Leipziger Straße 29, 09596 Freiberg, Germany
| | - Lorenz Adrian
- Fachgebiet Applied Biochemistry, Technische Universität Berlin , Gustav-Meyer-Allee 25, 13355 Berlin, Germany
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135
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Alfán-Guzmán R, Ertan H, Manefield M, Lee M. Isolation and Characterization of Dehalobacter sp. Strain TeCB1 Including Identification of TcbA: A Novel Tetra- and Trichlorobenzene Reductive Dehalogenase. Front Microbiol 2017; 8:558. [PMID: 28421054 PMCID: PMC5379058 DOI: 10.3389/fmicb.2017.00558] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 03/16/2017] [Indexed: 11/13/2022] Open
Abstract
Dehalobacter sp. strain TeCB1 was isolated from groundwater near Sydney, Australia, that is polluted with a range of organochlorines. The isolated strain is able to grow by reductive dechlorination of 1,2,4,5-tetrachlorobenzene to 1,3- and 1,4-dichlorobenzene with 1,2,4-trichlorobenzene being the intermediate daughter product. Transient production of 1,2-dichlorobenzene was detected with subsequent conversion to monochlorobenzene. The dehalogenation capability of strain TeCB1 to respire 23 alternative organochlorines was examined and shown to be limited to the use of 1,2,4,5-tetrachlorobenzene and 1,2,4-trichlorobenzene. Growth on 1,2,4-trichlorobenzene resulted in the production of predominantly 1,3- and 1,4-dichlorobenzene. The inability of strain TeCB1 to grow on 1,2-dichlorobenzene indicated that the production of monochlorobenzene during growth on 1,2,4,5-tetarchlorobezene was cometabolic. The annotated genome of strain TeCB1 contained only one detectable 16S rRNA gene copy and genes for 23 full-length and one truncated Reductive Dehalogenase (RDase) homologs, five unique to strain TeCB1. Identification and functional characterization of the 1,2,4,5-tetrachlorobenzene and 1,2,4-trichlorobenzene RDase (TcbA) was achieved using native-PAGE coupled with liquid chromatography tandem mass spectrometry. Interestingly, TcbA showed higher amino acid identity with tetrachloroethene reductases PceA (95% identity) from Dehalobacter restrictus PER-K23 and Desulfitobacterium hafniense Y51 than with the only other chlorinated benzene reductase [i.e., CbrA (30% identity)] functionally characterized to date.
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Affiliation(s)
- Ricardo Alfán-Guzmán
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, SydneyNSW, Australia
| | - Haluk Ertan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, SydneyNSW, Australia.,Department of Molecular Biology and Genetics, Istanbul UniversityIstanbul, Turkey
| | - Mike Manefield
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, SydneyNSW, Australia
| | - Matthew Lee
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, SydneyNSW, Australia
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136
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Temme HR, Sande K, Yan T, Novak PJ. Rapid Enrichment of Dehalococcoides-Like Bacteria by Partial Hydrophobic Separation. Appl Environ Microbiol 2017; 83:e02946-16. [PMID: 28087526 PMCID: PMC5335530 DOI: 10.1128/aem.02946-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/05/2017] [Indexed: 11/20/2022] Open
Abstract
Organohalide-respiring bacteria can be difficult to enrich and isolate, which can limit research on these important organisms. The goal of this research was to develop a method to rapidly (minutes to days) enrich these organisms from a mixed community. The method presented is based on the hypothesis that organohalide-respiring bacteria would be more hydrophobic than other bacteria as they dehalogenate hydrophobic compounds. The method developed tests this hypothesis by separating a portion of putative organohalide-respiring bacteria, those phylogenetically related to Dehalococcoides mccartyi, at the interface between a hydrophobic organic solvent and an aqueous medium. This novel partial separation technique was tested with a polychlorinated biphenyl-enriched sediment-free culture, a tetrachloroethene-enriched digester sludge culture, and uncontaminated lake sediment. Significantly higher fractions, up to 20.4 times higher, of putative organohalide-respiring bacteria were enriched at the interface between the medium and either hexadecane or trichloroethene. The selective partial separation of these putative organohalide-respiring bacteria occurred after 20 min, strongly suggesting that the separation was a result of physical-chemical interactions between the cell surface and hydrophobic solvent. Dechlorination activity postseparation was verified by the production of cis-dichloroethene when amended with tetrachloroethene. A longer incubation time of 6 days prior to separation with trichloroethene increased the total number of putative organohalide-respiring bacteria. This method provides a way to quickly separate some of the putative organohalide-respiring bacteria from other bacteria, thereby improving our ability to study multiple and different bacteria of potential interest and improving knowledge of these bacteria.IMPORTANCE Organohalide-respiring bacteria, bacteria capable of respiring chlorinated contaminants, can be difficult to enrich, which can limit their predictable use for the bioremediation of contaminated sites. This paper describes a method to quickly separate Dehalococcoides-like bacteria, a group of organisms containing organohalide-respiring bacteria, from other bacteria in a mixed community. From this work, Dehalococcoides-like bacteria appear to have a hydrophobic cell surface, facilitating a rapid (20 min) partial separation from a mixed culture at the surface of a hydrophobic liquid. This method was verified in a polychlorinated biphenyl-enriched sediment-free culture, an anaerobic digester sludge, and uncontaminated sediment. The method described can drastically reduce the amount of time required to partially separate Dehalococcoides-like bacteria from a complex mixed culture, improving researchers' ability to study these important bacteria.
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Affiliation(s)
- Hanna R Temme
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kipp Sande
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Tao Yan
- Department of Civil and Environmental Engineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Paige J Novak
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA
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137
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Dehalococcoides and general bacterial ecology of differentially trichloroethene dechlorinating flow-through columns. Appl Microbiol Biotechnol 2017; 101:4799-4813. [PMID: 28213734 DOI: 10.1007/s00253-017-8180-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 02/03/2017] [Indexed: 10/20/2022]
Abstract
The diversity of Dehalococcoides mccartyi (Dhc) and/or other organohalide respiring or associated microorganisms in parallel, partial, or complete trichloroethene (TCE) dehalogenating systems has not been well described. The composition of Dhc populations and the associated bacterial community that developed over 7.5 years in the top layer (0-10 cm) of eight TCE-fed columns were examined using pyrosequencing. Columns biostimulated with one of three carbon sources, along with non-stimulated controls, developed into complete (ethene production, whey amended), partial (cis-dichloroethene (DCE) and VC, an emulsified oil with nonionic surfactant), limited (<5 % cis-DCE and 95 % TCE, an emulsified oil), and non- (controls) TCE dehalogenating systems. Bioaugmentation of one column of each treatment with Bachman Road enrichment culture did not change Dhc populations nor the eventual degree of TCE dehalogenation. Pyrosequencing revealed high diversity among Dhc strains. There were 13 OTUs that were represented by more than 1000 sequences each. Cornell group-related populations dominated in complete TCE dehalogenating columns, while Pinellas group related Dhc dominated in all other treatments. General microbial communities varied with biostimulation, and three distinct microbial communities were established: one each for whey, oils, and control treatments. Bacterial genera, including Dehalobacter, Desulfitobacterium, Sulfurospirillum, Desulfuromonas, and Geobacter, all capable of partial TCE dehalogenation, were abundant in the limited and partial TCE dehalogenating systems. Dhc strain diversity was wider than previously reported and their composition within the community varied significantly depending on the nature of the carbon source applied and/or changes in the Dhc associated partners that fostered different biogeochemical conditions across the columns.
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138
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Dam HT, Häggblom MM. Impact of estuarine gradients on reductive dechlorination of 1,2,3,4-tetrachlorodibenzo-p-dioxin in river sediment enrichment cultures. CHEMOSPHERE 2017; 168:1177-1185. [PMID: 27817900 DOI: 10.1016/j.chemosphere.2016.10.082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 09/17/2016] [Accepted: 10/22/2016] [Indexed: 06/06/2023]
Abstract
Polychlorinated dibenzo-p-dioxins (PCDDs) are among the most persistent organic pollutants. Although the total input of PCDDs into the environment has decreased substantially over the past four decades, their input via non-point sources is still increasing, especially in estuarine metropolitan areas. Here we report on the microbially mediated reductive dechlorination of PCDDs in anaerobic enrichment cultures established from sediments collected from five locations along the Hackensack River, NJ and investigate the impacts of sediment physicochemical characteristics on dechlorination activity. Dechlorination of 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TeCDD) and abundance of Dehalococcoides spp. negatively correlated with salinity and sulfate concentration in sediments used to establish the cultures. 1,2,3,4-TeCDD was dechlorinated to a lesser extent in cultures established from sediments from the tidally influenced estuarine mouth of the river. In cultures established from low salinity sediments, 1,2,3,4-TeCDD was reductively dechlorinated with the accumulation of 2-monochlorodibenzo-p-dioxin as the major product. Sulfate concentrations above 2 mM inhibited 1,2,3,4-TecDD dechlorination activity. Consecutive lateral- and peri- dechlorination took place in enrichment cultures with a minimal accumulation of 2,3-dichlorodibenzo-p-dioxin in active cultures. A Dehalococcoides spp. community was enriched and accounted for up to 64% of Chloroflexi detected in these sediment cultures.
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Affiliation(s)
- Hang T Dam
- Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, 76 Lipman Drive, New Brunswick, NJ 08901, USA.
| | - Max M Häggblom
- Department of Biochemistry and Microbiology, Rutgers, the State University of New Jersey, 76 Lipman Drive, New Brunswick, NJ 08901, USA.
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139
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Complete Genome Sequence of Dehalococcoides mccartyi Strain WBC-2, Capable of Anaerobic Reductive Dechlorination of Vinyl Chloride. GENOME ANNOUNCEMENTS 2016; 4:4/6/e01375-16. [PMID: 28007851 PMCID: PMC5180379 DOI: 10.1128/genomea.01375-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dehalococcoides mccartyi strain WBC-2 dechlorinates carcinogen vinyl chloride to ethene in the West Branch Canal Creek (WBC-2) microbial consortium used for bioaugmentation. We assembled and closed the complete genome sequence of this prokaryote using metagenomic sequencing from an enrichment culture.
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140
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Chaussonnerie S, Saaidi PL, Ugarte E, Barbance A, Fossey A, Barbe V, Gyapay G, Brüls T, Chevallier M, Couturat L, Fouteau S, Muselet D, Pateau E, Cohen GN, Fonknechten N, Weissenbach J, Le Paslier D. Microbial Degradation of a Recalcitrant Pesticide: Chlordecone. Front Microbiol 2016; 7:2025. [PMID: 28066351 PMCID: PMC5167691 DOI: 10.3389/fmicb.2016.02025] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 12/02/2016] [Indexed: 01/17/2023] Open
Abstract
Chlordecone (Kepone®) is a synthetic organochlorine insecticide (C10Cl10O) used worldwide mostly during the 1970 and 1980s. Its intensive application in the French West Indies to control the banana black weevil Cosmopolites sordidus led to a massive environmental pollution. Persistence of chlordecone in soils and water for numerous decades even centuries causes global public health and socio-economic concerns. In order to investigate the biodegradability of chlordecone, microbial enrichment cultures from soils contaminated by chlordecone or other organochlorines and from sludge of a wastewater treatment plant have been conducted. Different experimental procedures including original microcosms were carried out anaerobically over long periods of time. GC-MS monitoring resulted in the detection of chlorinated derivatives in several cultures, consistent with chlordecone biotransformation. More interestingly, disappearance of chlordecone (50 μg/mL) in two bacterial consortia was concomitant with the accumulation of a major metabolite of formula C9Cl5H3 (named B1) as well as two minor metabolites C10Cl9HO (named A1) and C9Cl4H4 (named B3). Finally, we report the isolation and the complete genomic sequences of two new Citrobacter isolates, closely related to Citrobacter amalonaticus, and that were capable of reproducing chlordecone transformation. Further characterization of these Citrobacter strains should yield deeper insights into the mechanisms involved in this transformation process.
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Affiliation(s)
- Sébastien Chaussonnerie
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Pierre-Loïc Saaidi
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Edgardo Ugarte
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Agnès Barbance
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Aurélie Fossey
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Valérie Barbe
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de Génomique Evry, France
| | - Gabor Gyapay
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de Génomique Evry, France
| | - Thomas Brüls
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Marion Chevallier
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Loïc Couturat
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Stéphanie Fouteau
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de Génomique Evry, France
| | - Delphine Muselet
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Emilie Pateau
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | | | - Nuria Fonknechten
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Jean Weissenbach
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
| | - Denis Le Paslier
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction de la Recherche Fondamentale, Institut de GénomiqueEvry, France; Université d'Evry Val d'EssonneEvry, France; Centre National de la Recherche Scientifique, UMR8030, Génomique métaboliqueEvry, France
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141
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Hieke ASC, Brinkmeyer R, Yeager KM, Schindler K, Zhang S, Xu C, Louchouarn P, Santschi PH. Widespread Distribution of Dehalococcoides mccartyi in the Houston Ship Channel and Galveston Bay, Texas, Sediments and the Potential for Reductive Dechlorination of PCDD/F in an Estuarine Environment. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2016; 18:630-644. [PMID: 27844293 DOI: 10.1007/s10126-016-9723-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/04/2016] [Indexed: 05/14/2023]
Abstract
Sediments in the Houston Ship Channel and upper Galveston Bay, Texas, USA, are polluted with polychlorinated dibenzo-p-dioxins/furans (PCDD/F; ≤46,000 ng/kg dry weight (wt.)) with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener, contributing >50 % of the total toxic equivalents (TEQ) at most locations. We measured PCDD/F concentrations in sediments and evaluated the potential for enhanced in situ biodegradation by surveying for Dehalococcoides mccartyi, an obligate organohalide respiring bacterium. Dehalococcoides spp. (98 % similar to D. mccartyi) and 22 other members of the class Dehalococcoidia were predominant 16S ribosomal RNA (rRNA) phylotypes. Dehalococcoides spp. were also present in the active fraction of the bacterial community. Presence/absence PCR screening detected D. mccartyi in sediment cores and sediment grab samples having at least 1 ng/kg dry wt. TEQ at salinities ranging from 0.6 to 19.5 PSU, indicating that they are widespread in the estuarine environment. Organic carbon-only and organic carbon + sulfate-amended sediment microcosm experiments resulted in ∼60 % reduction of ambient 2,3,7,8-TCDD in just 24 months leading to reductions in total TEQs by 38.4 and 45.0 %, respectively, indicating that 2,3,7,8-TCDD degradation is occurring at appreciable rates.
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Affiliation(s)
- Anne-Sophie Charlotte Hieke
- Department of Oceanography, Texas A&M University, 3146 TAMU, College Station, TX, 77843, USA.
- Department of Poultry Science, Texas A&M University, 2472 TAMU, College Station, TX, 77843, USA.
| | - Robin Brinkmeyer
- Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA
| | - Kevin M Yeager
- Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA
- Department of Earth and Environmental Sciences, University of Kentucky, 101 Slone Research Building, Lexington, KY, 40506, USA
| | - Kimberly Schindler
- Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA
- Department of Earth and Environmental Sciences, University of Kentucky, 101 Slone Research Building, Lexington, KY, 40506, USA
| | - Saijin Zhang
- Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA
| | - Chen Xu
- Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA
| | - Patrick Louchouarn
- Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA
| | - Peter H Santschi
- Department of Marine Science, Texas A&M University, 200 Seawolf Parkway, Galveston, TX, 77553, USA
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142
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Mayer-Blackwell K, Fincker M, Molenda O, Callahan B, Sewell H, Holmes S, Edwards EA, Spormann AM. 1,2-Dichloroethane Exposure Alters the Population Structure, Metabolism, and Kinetics of a Trichloroethene-Dechlorinating Dehalococcoides mccartyi Consortium. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:12187-12196. [PMID: 27809491 DOI: 10.1021/acs.est.6b02957] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Bioremediation of groundwater contaminated with chlorinated aliphatic hydrocarbons such as perchloroethene and trichloroethene can result in the accumulation of the undesirable intermediate vinyl chloride. Such accumulation can either be due to the absence of specific vinyl chloride respiring Dehalococcoides mccartyi or to the inhibition of such strains by the metabolism of other microorganisms. The fitness of vinyl chloride respiring Dehalococcoides mccartyi subpopulations is particularly uncertain in the presence of chloroethene/chloroethane cocontaminant mixtures, which are commonly found in contaminated groundwater. Therefore, we investigated the structure of Dehalococcoides populations in a continuously fed reactor system under changing chloroethene/ethane influent conditions. We observed that increasing the influent ratio of 1,2-dichloroethane to trichloroethene was associated with ecological selection of a tceA-containing Dehalococcoides population relative to a vcrA-containing Dehalococcoides population. Although both vinyl chloride and 1,2-dichloroethane could be simultaneously transformed to ethene, prolonged exposure to 1,2-dichloroethane diminished the vinyl chloride transforming capacity of the culture. Kinetic tests revealed that dechlorination of 1,2-dichloroethane by the consortium was strongly inhibited by cis-dichloroethene but not vinyl chloride. Native polyacrylamide gel electrophoresis and mass spectrometry revealed that a trichloroethene reductive dehalogenase (TceA) homologue was the most consistently expressed of four detectable reductive dehalogenases during 1,2-dichloroethane exposure, suggesting that it catalyzes the reductive dihaloelimination of 1,2-dichloroethane to ethene.
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Affiliation(s)
- Koshlan Mayer-Blackwell
- Civil and Environmental Engineering, ‡Chemical Engineering, and §Department of Statistics, Stanford University , Stanford, California 94305, United States
- Chemical Engineering & Applied Chemistry, and ⊥Cell and Systems Biology, University of Toronto , Toronto, Ontario M5S 3E5, Canada
| | - Maeva Fincker
- Civil and Environmental Engineering, ‡Chemical Engineering, and §Department of Statistics, Stanford University , Stanford, California 94305, United States
- Chemical Engineering & Applied Chemistry, and ⊥Cell and Systems Biology, University of Toronto , Toronto, Ontario M5S 3E5, Canada
| | - Olivia Molenda
- Civil and Environmental Engineering, ‡Chemical Engineering, and §Department of Statistics, Stanford University , Stanford, California 94305, United States
- Chemical Engineering & Applied Chemistry, and ⊥Cell and Systems Biology, University of Toronto , Toronto, Ontario M5S 3E5, Canada
| | - Benjamin Callahan
- Civil and Environmental Engineering, ‡Chemical Engineering, and §Department of Statistics, Stanford University , Stanford, California 94305, United States
- Chemical Engineering & Applied Chemistry, and ⊥Cell and Systems Biology, University of Toronto , Toronto, Ontario M5S 3E5, Canada
| | - Holly Sewell
- Civil and Environmental Engineering, ‡Chemical Engineering, and §Department of Statistics, Stanford University , Stanford, California 94305, United States
- Chemical Engineering & Applied Chemistry, and ⊥Cell and Systems Biology, University of Toronto , Toronto, Ontario M5S 3E5, Canada
| | - Susan Holmes
- Civil and Environmental Engineering, ‡Chemical Engineering, and §Department of Statistics, Stanford University , Stanford, California 94305, United States
- Chemical Engineering & Applied Chemistry, and ⊥Cell and Systems Biology, University of Toronto , Toronto, Ontario M5S 3E5, Canada
| | - Elizabeth A Edwards
- Civil and Environmental Engineering, ‡Chemical Engineering, and §Department of Statistics, Stanford University , Stanford, California 94305, United States
- Chemical Engineering & Applied Chemistry, and ⊥Cell and Systems Biology, University of Toronto , Toronto, Ontario M5S 3E5, Canada
| | - Alfred M Spormann
- Civil and Environmental Engineering, ‡Chemical Engineering, and §Department of Statistics, Stanford University , Stanford, California 94305, United States
- Chemical Engineering & Applied Chemistry, and ⊥Cell and Systems Biology, University of Toronto , Toronto, Ontario M5S 3E5, Canada
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143
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Tiedt O, Mergelsberg M, Boll K, Müller M, Adrian L, Jehmlich N, von Bergen M, Boll M. ATP-Dependent C-F Bond Cleavage Allows the Complete Degradation of 4-Fluoroaromatics without Oxygen. mBio 2016; 7:e00990-16. [PMID: 27507824 PMCID: PMC4992971 DOI: 10.1128/mbio.00990-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/14/2016] [Indexed: 01/29/2023] Open
Abstract
UNLABELLED Complete biodegradation of the abundant and persistent fluoroaromatics requires enzymatic cleavage of an arylic C-F bond, probably the most stable single bond of a biodegradable organic molecule. While in aerobic microorganisms defluorination of fluoroaromatics is initiated by oxygenases, arylic C-F bond cleavage has never been observed in the absence of oxygen. Here, an oxygen-independent enzymatic aryl fluoride bond cleavage is described during the complete degradation of 4-fluorobenzoate or 4-fluorotoluene to CO2 and HF in the denitrifying Thauera aromatica: the ATP-dependent defluorination of 4-fluorobenzoyl-coenzyme A (4-F-BzCoA) to benzoyl-coenzyme A (BzCoA) and HF, catalyzed by class I BzCoA reductase (BCR). Adaptation to growth with the fluoroaromatics was accomplished by the downregulation of a promiscuous benzoate-CoA ligase and the concomitant upregulation of 4-F-BzCoA-defluorinating/dearomatizing BCR on the transcriptional level. We propose an unprecedented mechanism for reductive arylic C-F bond cleavage via a Birch reduction-like mechanism resulting in a formal nucleophilic aromatic substitution. In the proposed anionic 4-fluorodienoyl-CoA transition state, fluoride elimination to BzCoA is favored over protonation to a fluorinated cyclic dienoyl-CoA. IMPORTANCE Organofluorides are produced as pesticides, pharmaceuticals, and other chemicals and comprise approximately one quarter of all organic compounds in the pharmaceutical and agricultural sectors; they are considered a growing class of environmentally relevant persistent pollutants. Especially in the case of fluoroaromatics, biodegradation is hampered by the extreme stability of the arylic C-F bond. In aerobic microorganisms, degradation proceeds via oxygenase-dependent C-F bond cleavage reactions, whereas the enzymes involved in the degradation of fluoroaromatics at anoxic sites are unknown. Here we report a strategy for the complete biodegradation of a fluoroaromatic to CO2 and HF in a denitrifying bacterium via activation to a CoA ester, followed by oxygen-independent arylic C-F bond cleavage catalyzed by an ATP-dependent enzyme. This reaction, in conjunction with a transcriptional adaptation to fluorinated growth substrates, is essential for the anoxic biodegradation of 4-fluorobenzoate/4-F-toluene and probably other fluoroaromatics.
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Affiliation(s)
- Oliver Tiedt
- Faculty of Biology, Microbiology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Mario Mergelsberg
- Faculty of Biology, Microbiology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Kerstin Boll
- Faculty of Biology, Microbiology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Michael Müller
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Lorenz Adrian
- Department of Isotope Biogeochemistry Proteomics, Helmholtz Centre for Environmental Research, UFZ, Leipzig, Germany
| | - Nico Jehmlich
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research, UFZ, Leipzig, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research, UFZ, Leipzig, Germany Faculty of Biosciences, Pharmacy and Psychology, University of Leipzig, Leipzig, Germany Department of Chemistry and Bioscience, University of Aalborg, Aalborg, Denmark
| | - Matthias Boll
- Faculty of Biology, Microbiology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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Chen M, Liu C, Chen P, Tong H, Li F, Qiao J, Lan Q. Dynamics of the microbial community and Fe(III)-reducing and dechlorinating microorganisms in response to pentachlorophenol transformation in paddy soil. JOURNAL OF HAZARDOUS MATERIALS 2016; 312:97-105. [PMID: 27017395 DOI: 10.1016/j.jhazmat.2016.03.059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 03/01/2016] [Accepted: 03/21/2016] [Indexed: 06/05/2023]
Abstract
Soil microorganisms play crucial roles in the fates of pollutants, and understanding the behaviour of these microorganisms is critical for the bioremediation of PCP-contaminated soil. However, shifts remain unclear in the community structure and Fe(III)-reducing and dechlorinating microorganisms during PCP transformation processes, especially during the stages from the lag to the dechlorination phase and from the dechlorination to the stationary phase. Here, a set of lab-scale experiments was performed to investigate the microbial community dynamics accompanying PCP transformation in paddy soil. 19μM of PCP was biotransformed completely in 10days for all treatments. T-RFLP analysis of the microbial community confirmed that Veillonellaceae and Clostridium sensu stricto were the dominant groups during PCP transformation, and the structures of the microbial communities changed due to the degree of biotransformation and the addition of lactate and AQDS. However, similar temporal dynamics of the microbial communities were obtained among all treatments. Furthermore, as revealed by quantitative PCR, the dynamics of Fe(III)-reducing and dechlorinating microorganisms, including Geobacter sp., Shewanella sp., and Dehalobacter sp., were consistent with the transformation kinetics of PCP, suggesting the critical roles played by these microorganisms in PCP transformation. These findings are valuable for making predictions of and proposing methods for the microbial detoxification of residual organochlorine pesticides in paddy soil.
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Affiliation(s)
- Manjia Chen
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China
| | - Chengshuai Liu
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550009, China.
| | - Pengcheng Chen
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China
| | - Hui Tong
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China; State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550009, China
| | - Fangbai Li
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China.
| | - Jiangtao Qiao
- Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China
| | - Qing Lan
- Guangdong Polytechnic of Environmental Protection Engineering, Foshan, Guangdong 528216, China
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145
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Anaerobic Bioreactors for the Treatment of Chlorinated Hydrocarbons. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1201/b19347-15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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146
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Key TA, Richmond DP, Bowman KS, Cho YJ, Chun J, da Costa MS, Rainey FA, Moe WM. Genome sequence of the organohalide-respiring Dehalogenimonas alkenigignens type strain (IP3-3(T)). Stand Genomic Sci 2016; 11:44. [PMID: 27340512 PMCID: PMC4918011 DOI: 10.1186/s40793-016-0165-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 05/31/2016] [Indexed: 11/13/2022] Open
Abstract
Dehalogenimonas alkenigignens IP3-3T is a strictly anaerobic, mesophilic, Gram negative staining bacterium that grows by organohalide respiration, coupling the oxidation of H2 to the reductive dehalogenation of polychlorinated alkanes. Growth has not been observed with any non-polyhalogenated alkane electron acceptors. Here we describe the features of strain IP3-3T together with genome sequence information and its annotation. The 1,849,792 bp high-quality-draft genome contains 1936 predicted protein coding genes, 47 tRNA genes, a single large subunit rRNA (23S-5S) locus, and a single, orphan, small unit rRNA (16S) locus. The genome contains 29 predicted reductive dehalogenase genes, a large majority of which lack cognate genes encoding membrane anchoring proteins.
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Affiliation(s)
- Trent A Key
- Louisiana State University, Baton Rouge, LA USA
| | | | | | - Yong-Joon Cho
- ChunLab, Inc., Seoul National University, Seoul, Republic of Korea
| | - Jongsik Chun
- ChunLab, Inc., Seoul National University, Seoul, Republic of Korea
| | - Milton S da Costa
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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147
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Praveckova M, Brennerova MV, Holliger C, De Alencastro F, Rossi P. Indirect Evidence Link PCB Dehalogenation with Geobacteraceae in Anaerobic Sediment-Free Microcosms. Front Microbiol 2016; 7:933. [PMID: 27379063 PMCID: PMC4909783 DOI: 10.3389/fmicb.2016.00933] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/31/2016] [Indexed: 11/26/2022] Open
Abstract
Although polychlorinated biphenyls (PCBs) production was brought to a halt 30 years ago, recalcitrance to degradation makes them a major environmental pollutant at a global scale. Previous studies confirmed that organohalide-respiring bacteria (OHRB) were capable of utilizing chlorinated congeners as electron acceptor. OHRB belonging to the Phyla Chloroflexi and Firmicutes are nowadays considered as the main PCB-dechlorinating organisms. In this study, we aimed at exploring the involvement of other taxa in PCB dechlorination using sediment-free microcosms (SFMs) and the Delor PCB mixture. High rates of congener dehalogenation (up to 96%) were attained in long-term incubations of up to 692 days. Bacterial communities were dominated by Chloroflexi, Proteobacteria, and Firmicutes, among strictly simplified community structures composed of 12 major phyla only. In a first batch of SFMs, Dehalococcoides mccartyi closely affiliated with strains CG4 and CBDB1 was considered as the main actor associated with congener dehalogenation. Addition of 2-bromoethanesulfonate (BES), a known inhibitor of methanogenic activity in a second batch of SFMs had an adverse effect on the abundance of Dehalococcoides sp. Only two sequences affiliated to this Genus could be detected in two (out of six) BES-treated SFMs, contributing to a mere 0.04% of the communities. BES-treated SFMs showed very different community structures, especially in the contributions of organisms involved in fermentation and syntrophic activities. Indirect evidence provided by both statistical and phylogenetic analysis validated the implication of a new cluster of actors, distantly affiliated with the Family Geobacteraceae (Phylum δ-Proteobacteria), in the dehalogenation of low chlorinated PCB congeners. Members of this Family are known already for their dehalogenation capacity of chlorinated solvents. As a result, the present study widens the knowledge for the phylogenetic reservoir of indigenous PCB dechlorinating taxa.
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Affiliation(s)
- Martina Praveckova
- Laboratory of Molecular Genetics of Bacteria, Institute of Microbiology, Academy of Sciences of the Czech RepublicPrague, Czech Republic; Faculty of Science, Charles University PraguePrague, Czech Republic
| | - Maria V Brennerova
- Laboratory of Molecular Genetics of Bacteria, Institute of Microbiology, Academy of Sciences of the Czech Republic Prague, Czech Republic
| | - Christof Holliger
- Laboratory for Environmental Biotechnology, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne Lausanne, Switzerland
| | - Felippe De Alencastro
- Central Environmental Laboratory, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne Lausanne, Switzerland
| | - Pierre Rossi
- Central Environmental Laboratory, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne Lausanne, Switzerland
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148
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Fullerton H, Moyer CL. Comparative Single-Cell Genomics of Chloroflexi from the Okinawa Trough Deep-Subsurface Biosphere. Appl Environ Microbiol 2016; 82:3000-3008. [PMID: 26969693 PMCID: PMC4959059 DOI: 10.1128/aem.00624-16] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/04/2016] [Indexed: 11/25/2022] Open
Abstract
UNLABELLED Chloroflexi small-subunit (SSU) rRNA gene sequences are frequently recovered from subseafloor environments, but the metabolic potential of the phylum is poorly understood. The phylum Chloroflexi is represented by isolates with diverse metabolic strategies, including anoxic phototrophy, fermentation, and reductive dehalogenation; therefore, function cannot be attributed to these organisms based solely on phylogeny. Single-cell genomics can provide metabolic insights into uncultured organisms, like the deep-subsurface Chloroflexi Nine SSU rRNA gene sequences were identified from single-cell sorts of whole-round core material collected from the Okinawa Trough at Iheya North hydrothermal field as part of Integrated Ocean Drilling Program (IODP) expedition 331 (Deep Hot Biosphere). Previous studies of subsurface Chloroflexi single amplified genomes (SAGs) suggested heterotrophic or lithotrophic metabolisms and provided no evidence for growth by reductive dehalogenation. Our nine Chloroflexi SAGs (seven of which are from the order Anaerolineales) indicate that, in addition to genes for the Wood-Ljungdahl pathway, exogenous carbon sources can be actively transported into cells. At least one subunit for pyruvate ferredoxin oxidoreductase was found in four of the Chloroflexi SAGs. This protein can provide a link between the Wood-Ljungdahl pathway and other carbon anabolic pathways. Finally, one of the seven Anaerolineales SAGs contains a distinct reductive dehalogenase homologous (rdhA) gene. IMPORTANCE Through the use of single amplified genomes (SAGs), we have extended the metabolic potential of an understudied group of subsurface microbes, the Chloroflexi These microbes are frequently detected in the subsurface biosphere, though their metabolic capabilities have remained elusive. In contrast to previously examined Chloroflexi SAGs, our genomes (several are from the order Anaerolineales) were recovered from a hydrothermally driven system and therefore provide a unique window into the metabolic potential of this type of habitat. In addition, a reductive dehalogenase gene (rdhA) has been directly linked to marine subsurface Chloroflexi, suggesting that reductive dehalogenation is not limited to the class Dehalococcoidia This discovery expands the nutrient-cycling and metabolic potential present within the deep subsurface and provides functional gene information relating to this enigmatic group.
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Affiliation(s)
- Heather Fullerton
- Department of Biology, Western Washington University, Bellingham, Washington, USA
| | - Craig L Moyer
- Department of Biology, Western Washington University, Bellingham, Washington, USA
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149
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Wasmund K, Cooper M, Schreiber L, Lloyd KG, Baker BJ, Petersen DG, Jørgensen BB, Stepanauskas R, Reinhardt R, Schramm A, Loy A, Adrian L. Single-Cell Genome and Group-Specific dsrAB Sequencing Implicate Marine Members of the Class Dehalococcoidia (Phylum Chloroflexi) in Sulfur Cycling. mBio 2016; 7:e00266-16. [PMID: 27143384 PMCID: PMC4959651 DOI: 10.1128/mbio.00266-16] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/05/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The marine subsurface sediment biosphere is widely inhabited by bacteria affiliated with the class Dehalococcoidia (DEH), phylum Chloroflexi, and yet little is known regarding their metabolisms. In this report, genomic content from a single DEH cell (DEH-C11) with a 16S rRNA gene that was affiliated with a diverse cluster of 16S rRNA gene sequences prevalent in marine sediments was obtained from sediments of Aarhus Bay, Denmark. The distinctive gene content of this cell suggests metabolic characteristics that differ from those of known DEH and Chloroflexi The presence of genes encoding dissimilatory sulfite reductase (Dsr) suggests that DEH could respire oxidized sulfur compounds, although Chloroflexi have never been implicated in this mode of sulfur cycling. Using long-range PCR assays targeting DEH dsr loci, dsrAB genes were amplified and sequenced from various marine sediments. Many of the amplified dsrAB sequences were affiliated with the DEH Dsr clade, which we propose equates to a family-level clade. This provides supporting evidence for the potential for sulfite reduction by diverse DEH species. DEH-C11 also harbored genes encoding reductases for arsenate, dimethyl sulfoxide, and halogenated organics. The reductive dehalogenase homolog (RdhA) forms a monophyletic clade along with RdhA sequences from various DEH-derived contigs retrieved from available metagenomes. Multiple facts indicate that this RdhA may not be a terminal reductase. The presence of other genes indicated that nutrients and energy may be derived from the oxidation of substituted homocyclic and heterocyclic aromatic compounds. Together, these results suggest that marine DEH play a previously unrecognized role in sulfur cycling and reveal the potential for expanded catabolic and respiratory functions among subsurface DEH. IMPORTANCE Sediments underlying our oceans are inhabited by microorganisms in cell numbers similar to those estimated to inhabit the oceans. Microorganisms in sediments consist of various diverse and uncharacterized groups that contribute substantially to global biogeochemical cycles. Since most subsurface microorganisms continue to evade cultivation, possibly due to very slow growth, we obtained and analyzed genomic information from a representative of one of the most widespread and abundant, yet uncharacterized bacterial groups of the marine subsurface. We describe several key features that may contribute to their widespread distribution, such as respiratory flexibility and the potential to use oxidized sulfur compounds, which are abundant in marine environments, as electron acceptors. Together, these data provide important information that can be used to assist in designing enrichment strategies or other postgenomic studies, while also improving our understanding of the diversity and distribution of dsrAB genes, which are widely used functional marker genes for sulfur-cycling microbes.
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Affiliation(s)
- Kenneth Wasmund
- Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network Chemistry meets Microbiology, University of Vienna, Vienna, Austria
| | - Myriel Cooper
- Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Lars Schreiber
- Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus, Denmark
| | - Karen G Lloyd
- Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus, Denmark
| | - Brett J Baker
- Department of Marine Science, University of Texas-Austin, Marine Science Institute, Port Aransas, Texas, USA
| | - Dorthe G Petersen
- Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus, Denmark
| | - Bo Barker Jørgensen
- Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus, Denmark
| | | | | | - Andreas Schramm
- Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus, Denmark
| | - Alexander Loy
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Research Network Chemistry meets Microbiology, University of Vienna, Vienna, Austria
| | - Lorenz Adrian
- Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
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150
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Nijenhuis I, Kuntze K. Anaerobic microbial dehalogenation of organohalides — state of the art and remediation strategies. Curr Opin Biotechnol 2016; 38:33-8. [DOI: 10.1016/j.copbio.2015.11.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 11/03/2015] [Indexed: 11/26/2022]
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