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Wang Z, Yu Y, Zhao R, Li A. Construction of a synthetic anaerobic dechlorination microbiome to degrade chlorinated ethenes by application of metabolic interactions principle. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 955:176981. [PMID: 39427906 DOI: 10.1016/j.scitotenv.2024.176981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 10/05/2024] [Accepted: 10/14/2024] [Indexed: 10/22/2024]
Abstract
Bioaugmentation is a bioremediation approach to treat groundwater contaminated with chlorinated ethenes, but currently it faces challenges such as poor microbiome stability and effectiveness, due to blind species integration and metabolic inhibition. The objective of this study was to create a controllable and functionally stable microbial community for dichlorination application. For this, we utilized targeted screening to identify dechlorinating bacteria from contaminated groundwater, that in combination would form an anaerobic dechlorination microbial community with stabilizing metabolic interactions between the constituents. The results showed that two organohalide-respiring bacterial (OHRB) species were isolated, and these were identified as Enterobacter bugandensis X4 and Enterobacter sichuanensis C4. Upon co-cultivation with lactic acid as the carbon source, the strains demonstrated metabolic interactions and synergistic dehalogenation ability towards trichloroethene (TCE). It was further demonstrated that the functional microbiome constructed with the strains was stable over time and exhibited a robust TCE degradation rate of 80.85% at 13.13 mg/L TCE within 10 days. Additionally, the complete conversion of TCE was achieved through microbiome bioaugmentation, this augmented microbiome increased the degradation rate towards 52.55 mg/L TCE by approximately 30% within 6 days. Additionally, bioaugmentation stimulated the growth of indigenous OHRB, such as Dehalobacter and Desulfovibrio. It also promoted a positive succession of the microbial community. These findings offer valuable insights into the microbial remediation of chlorinated ethenes-contaminated groundwater and offers novel ideas for the construction of an artificial functional microbiome.
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Affiliation(s)
- Zeyi Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Yang Yu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Rongjian Zhao
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - Ang Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China.
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2
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Hu M, Scott C. Toward the development of a molecular toolkit for the microbial remediation of per-and polyfluoroalkyl substances. Appl Environ Microbiol 2024; 90:e0015724. [PMID: 38477530 PMCID: PMC11022551 DOI: 10.1128/aem.00157-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024] Open
Abstract
Per- and polyfluoroalkyl substances (PFAS) are highly fluorinated synthetic organic compounds that have been used extensively in various industries owing to their unique properties. The PFAS family encompasses diverse classes, with only a fraction being commercially relevant. These substances are found in the environment, including in water sources, soil, and wildlife, leading to human exposure and fueling concerns about potential human health impacts. Although PFAS degradation is challenging, biodegradation offers a promising, eco-friendly solution. Biodegradation has been effective for a variety of organic contaminants but is yet to be successful for PFAS due to a paucity of identified microbial species capable of transforming these compounds. Recent studies have investigated PFAS biotransformation and fluoride release; however, the number of specific microorganisms and enzymes with demonstrable activity with PFAS remains limited. This review discusses enzymes that could be used in PFAS metabolism, including haloacid dehalogenases, reductive dehalogenases, cytochromes P450, alkane and butane monooxygenases, peroxidases, laccases, desulfonases, and the mechanisms of microbial resistance to intracellular fluoride. Finally, we emphasize the potential of enzyme and microbial engineering to advance PFAS degradation strategies and provide insights for future research in this field.
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Affiliation(s)
- Miao Hu
- CSIRO Environment, Black Mountain Science and Innovation Park, Canberra, ACT, Australia
| | - Colin Scott
- CSIRO Environment, Black Mountain Science and Innovation Park, Canberra, ACT, Australia
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3
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Zhong H, Lyu H, Wang Z, Tian J, Wu Z. Application of dissimilatory iron-reducing bacteria for the remediation of soil and water polluted with chlorinated organic compounds: Progress, mechanisms, and directions. CHEMOSPHERE 2024; 352:141505. [PMID: 38387660 DOI: 10.1016/j.chemosphere.2024.141505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
Chlorinated organic compounds are widely used as solvents, but they are pollutants that can have adverse effects on the environment and human health. Dissimilatory iron-reducing bacteria (DIRB) such as Shewanella and Geobacter have been applied to treat a wide range of halogenated organic compounds due to their specific biological properties. Until now, there has been no systematic review on the mechanisms of direct or indirect degradation of halogenated organic compounds by DIRB. This work summarizes the discussion of DIRB's ability to enhance the dechlorination of reaction systems through different pathways, both biological and biochemical. For biological dechlorination, some DIRB have self-dechlorination capabilities that directly dechlorinate by hydrolysis. Adjustment of dechlorination genes through genetic engineering can improve the dechlorination capabilities of DIRB. DIRB can also adjust the capacity for the microbial community to dechlorinate and provide nutrients to enhance the expression of dechlorination genes in other bacteria. In biochemical dechlorination, DIRB bioconverts Fe(III) to Fe(II), which is capable of dichlorination. On this basis, the DIRB-driven Fenton reaction can efficiently degrade chlorinated organics by continuously maintaining anoxic conditions to generate Fe(II) and oxic conditions to generate H2O2. DIRB can drive microbial fuel cells due to their electroactivity and have a good dechlorination capacity at low levels of energy consumption. The contribution of DIRB to the removal of pesticides, antibiotics and POPs is summarized. Then the DIRB electron transfer mechanism is discussed, which is core to their ability to dechlorinate. Finally, the prospect of future work on the removal of chlorine-containing organic pollutants by DIRB is presented, and the main challenges and further research directions are suggested.
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Affiliation(s)
- Hua Zhong
- Tianjin Key Laboratory of Clean Energy and Pollution Control, Hebei Engineering Research Center of Pollution Control in Power System, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China
| | - Honghong Lyu
- Tianjin Key Laboratory of Clean Energy and Pollution Control, Hebei Engineering Research Center of Pollution Control in Power System, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China.
| | - Zhiqiang Wang
- Tianjin Key Laboratory of Clean Energy and Pollution Control, Hebei Engineering Research Center of Pollution Control in Power System, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China
| | - Jingya Tian
- Tianjin Key Laboratory of Clean Energy and Pollution Control, Hebei Engineering Research Center of Pollution Control in Power System, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China
| | - Zhineng Wu
- Tianjin Key Laboratory of Clean Energy and Pollution Control, Hebei Engineering Research Center of Pollution Control in Power System, School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300401, China.
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4
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Ng TL, Silver PA. Sustainable B 12-Dependent Dehalogenation of Organohalides in E. coli. ACS Chem Biol 2024; 19:380-391. [PMID: 38254247 DOI: 10.1021/acschembio.3c00585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Microbial bioremediation can provide an environmentally friendly and scalable solution to treat contaminated soil and water. However, microbes have yet to optimize pathways for degrading persistent anthropogenic pollutants, in particular organohalides. In this work, we first expand our repertoire of enzymes useful for bioremediation. By screening a panel of cobalamin (B12)-dependent reductive dehalogenases, we identified previously unreported enzymes that dechlorinate perchloroethene and regioselectively deiodinate the thyroidal disruptor 2,4,6-triiodophenol. One deiodinase, encoded by the animal-associated anaerobe Clostridioides difficile, was demonstrated to dehalogenate the naturally occurring metabolites L-halotyrosines. In cells, several combinations of ferredoxin oxidoreductase and flavodoxin extract and transfer low-potential electrons from pyruvate to drive reductive dehalogenation without artificial reductants and mediators. This work provides new insights into a relatively understudied family of B12-dependent enzymes and sets the stage for engineering synthetic pathways for degrading unnatural small molecule pollutants.
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Affiliation(s)
- Tai L Ng
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, United States
- Wyss Institute of Biologically-Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
| | - Pamela A Silver
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, United States
- Wyss Institute of Biologically-Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
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Deng Z, Chen H, Wang J, Zhang N, Han Z, Xie Y, Zhang X, Fang X, Yu H, Zhang D, Yue Z, Zhang C. Marine Dehalogenator and Its Chaperones: Microbial Duties and Responses in 2,4,6-Trichlorophenol Dechlorination. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023. [PMID: 37478352 DOI: 10.1021/acs.est.3c03738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
Marine environments contain diverse halogenated organic compounds (HOCs), both anthropogenic and natural, nourishing a group of versatile organohalide-respiring bacteria (OHRB). Here, we identified a novel OHRB (Peptococcaceae DCH) with conserved motifs but phylogenetically diverse reductive dehalogenase catalytic subunit (RdhAs) from marine enrichment culture. Further analyses clearly demonstrate the horizontal gene transfer of rdhAs among marine OHRB. Moreover, 2,4,6-trichlorophenol (TCP) was dechlorinated to 2,4-dichlorophenol and terminated at 4-chlorophenol in culture. Dendrosporobacter and Methanosarcina were the two dominant genera, and the constructed and verified metabolic pathways clearly demonstrated that the former provided various substrates for other microbes, while the latter drew nutrients, but might provide little benefit to microbial dehalogenation. Furthermore, Dendrosporobacter could readily adapt to TCP, and sporulation-related proteins of Dendrosporobacter were significantly upregulated in TCP-free controls, whereas other microbes (e.g., Methanosarcina and Aminivibrio) became more active, providing insights into how HOCs shape microbial communities. Additionally, sulfate could affect the dechlorination of Peptococcaceae DCH, but not debromination. Considering their electron accessibility and energy generation, the results clearly demonstrate that bromophenols are more suitable than chlorophenols for the enrichment of OHRB in marine environments. This study will greatly enhance our understanding of marine OHRB (rdhAs), auxiliary microbes, and microbial HOC adaptive mechanisms.
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Affiliation(s)
- Zhaochao Deng
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China
| | - Haixin Chen
- BGI-Sanya, BGI-Shenzhen, Sanya 572025, China
| | - Jun Wang
- BGI-Sanya, BGI-Shenzhen, Sanya 572025, China
| | - Ning Zhang
- Department of Environmental Engineering, School of Chemical Engineering and Pharmacy, Henan University of Science and Technology, Luoyang 471000, Henan, China
| | - Zhiqiang Han
- Department of Marine Resources and Environment, Fishery College, Zhejiang Ocean University, Zhoushan 316002, Zhejiang, China
| | - Yeting Xie
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, Guangxi, China
| | - Xiaoyan Zhang
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, Guangxi, China
| | | | - Hao Yu
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China
| | - Dongdong Zhang
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China
| | - Zhen Yue
- BGI-Sanya, BGI-Shenzhen, Sanya 572025, China
| | - Chunfang Zhang
- Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, Zhoushan 316021, Zhejiang, China
- College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, Guangxi, China
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Asai M, Yoshida N, Kusakabe T, Ismaeil M, Nishiuchi T, Katayama A. Dehalococcoides mccartyi NIT01, a novel isolate, dechlorinates high concentrations of chloroethenes by expressing at least six different reductive dehalogenases. ENVIRONMENTAL RESEARCH 2022; 207:112150. [PMID: 34619124 DOI: 10.1016/j.envres.2021.112150] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/07/2021] [Accepted: 09/27/2021] [Indexed: 06/13/2023]
Abstract
This study presents the isolation of a novel strain of Dehalococcoides mccartyi, NIT01, which can completely dechlorinate up to 4.0 mM of trichloroethene to ethene via 1,2-cis-dichroroethene and vinyl chloride within 25 days. Strain NIT01 dechlorinated chloroethenes (CEs) at a temperature range of 25-32 °C and pH range of 6.5-7.8. The activity of the strain was inhibited by salt at more than 1.3% and inactivated by 1 h exposure to 2.0% air or 0.5 ppm hypochlorous acid. The genome of NIT01 was highly similar to that of the Dehalococcoides strains DCMB5, GT, 11a5, CBDB1, and CG5, and all included identical 16S rRNA genes. Moreover, NIT01 had 19 rdhA genes including NIT01-rdhA7 and rdhA13, which are almost identical to vcrA and pceA that encode known dehalogenases for tetrachloroethene and vinyl chloride, respectively. We also extracted RdhAs from the membrane fraction of NIT01 using 0.5% n-dodecyl-β-d-maltoside and separated them by anion exchange chromatography to identify those involved in CE dechlorination. LC/MS identification of the LDS-PAGE bands and RdhA activities in the fractions indicated cellular expression of six RdhAs. NIT01-RdhA7 (VcrA) and NIT01-RdhA15 were highly detected and NIT01-RdhA6 was the third-most detected. Among these three RdhAs, NIT01-RdhA15 and NIT01-RdhA6 had no biochemically identified relatives and were suggested to be novel functional dehalogenases for CEs. The expression of multiple dehalogenases may support bacterial tolerance to high concentrations of CEs.
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Affiliation(s)
- Masaki Asai
- Department of Civil and Environmental Engineering, Nagoya Institute of Technology (Nitech), Gokiso-Cho, Showa-Ku, Nagoya, Aichi, Japan
| | - Naoko Yoshida
- Department of Civil and Environmental Engineering, Nagoya Institute of Technology (Nitech), Gokiso-Cho, Showa-Ku, Nagoya, Aichi, Japan.
| | - Toshiya Kusakabe
- Department of Civil and Environmental Engineering, Nagoya Institute of Technology (Nitech), Gokiso-Cho, Showa-Ku, Nagoya, Aichi, Japan
| | - Mohamed Ismaeil
- Department of Environmental Engineering and Architecture, Graduate School of Environmental Studies, Nagoya University, Nagoya, 464-8603, Japan; Department of Microbiology, Faculty of Science, Ain Shams University, Cairo, Egypt
| | - Takumi Nishiuchi
- Division of Integrated Omics Research, Kanazawa University, Ishikawa, Japan
| | - Arata Katayama
- Department of Environmental Engineering and Architecture, Graduate School of Environmental Studies, Nagoya University, Nagoya, 464-8603, Japan
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7
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OUP accepted manuscript. FEMS Microbiol Ecol 2022; 98:6577122. [DOI: 10.1093/femsec/fiac054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 04/07/2022] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
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Halliwell T, Fisher K, Payne KAP, Rigby SEJ, Leys D. Catabolic Reductive Dehalogenase Substrate Complex Structures Underpin Rational Repurposing of Substrate Scope. Microorganisms 2020; 8:microorganisms8091344. [PMID: 32887524 PMCID: PMC7565698 DOI: 10.3390/microorganisms8091344] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 11/17/2022] Open
Abstract
Reductive dehalogenases are responsible for the reductive cleavage of carbon-halogen bonds during organohalide respiration. A variety of mechanisms have been proposed for these cobalamin and [4Fe-4S] containing enzymes, including organocobalt, radical, or cobalt-halide adduct based catalysis. The latter was proposed for the oxygen-tolerant Nitratireductor pacificus pht-3B catabolic reductive dehalogenase (NpRdhA). Here, we present the first substrate bound NpRdhA crystal structures, confirming a direct cobalt–halogen interaction is established and providing a rationale for substrate preference. Product formation is observed in crystallo due to X-ray photoreduction. Protein engineering enables rational alteration of substrate preference, providing a future blue print for the application of this and related enzymes in bioremediation.
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Affiliation(s)
- Tom Halliwell
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK; (T.H.); (K.F.); (K.A.P.P.); (S.E.J.R.)
| | - Karl Fisher
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK; (T.H.); (K.F.); (K.A.P.P.); (S.E.J.R.)
| | - Karl A. P. Payne
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK; (T.H.); (K.F.); (K.A.P.P.); (S.E.J.R.)
- Future Biomanufacturing Research Hub (FutureBRH), Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK
| | - Stephen E. J. Rigby
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK; (T.H.); (K.F.); (K.A.P.P.); (S.E.J.R.)
| | - David Leys
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK; (T.H.); (K.F.); (K.A.P.P.); (S.E.J.R.)
- Correspondence: ; Tel.: +44-161-306-51-50
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Romero-Cedillo L, Poggi-Varaldo HM, Santoyo-Salazar J, Escamilla-Alvarado C, Matsumoto-Kuwabara Y, Ponce-Noyola MT, Bretón-Deval L, García-Rocha M. Biological synthesis of iron nanoparticles using hydrolysates from a waste-based biorefinery. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:28649-28669. [PMID: 32347480 DOI: 10.1007/s11356-020-08729-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
The purpose of this work was to produce iron nanoparticles (Fe-NP) by microbial pathway from anaerobic bacteria grown in anaerobic fluidized bed reactors (AnFBRs) that constitute a new stage of a waste-based biorefinery. Bioparticles from biological fluidized bed reactors from a biorefinery of organic fraction of municipal solid wastes (that produces hydrolysates rich in reducing sugars) were nanodecorated (embedded nanobioparticle or nanodecorated bioparticle, ENBP) by biological reduction of iron salts. Factors "origin of bioparticles" (either from hydrogenogenic or methanogenic fluidized bed reactor) and "type of iron precursor salt" (iron chloride or iron citrate) were explored. SEM and high-resolution transmission electron microscopy (HRTEM) showed amorphous distribution of nanoparticles (NP) on the bioparticles surface, although small structures that are nanoparticle-like could be seen in the SEM micrographs. Some agglomeration of NPs was confirmed by DLS. Average NP size was lower in general for NP in ENBP-M than ENBP-H according to HRTEM. The factors did not have a significant influence on the specific surface area of NPs, which was high and in the range 490 to 650 m2 g-1. Analysis by EDS displayed consistent iron concentration 60-65% iron in nanoparticles present in ENBP-M (bioparticles previously grown in methanogenic bioreactor), whereas the iron concentration in NPs present in ENBP-H (bioparticles previously grown in hydrogenogenic bioreactor) was more variable in a range from 8.5 to 62%, depending on the iron salt. X-ray diffraction patterns showed the typical peaks for magnetite at 35° (3 1 1), 43° (4 0 0), and 62° (4 0 0); moreover, siderite diffraction pattern was found at 26° (0 1 2), 38° (1 1 0), and 42° (1 1 3). Results of infrared analysis of ENBP in our work were congruent with presence of magnetite and occasionally siderite determined by XRD analysis as well as presence of both Fe+2 and F+3 (and selected satellite signal peaks) observed by XPS. Our results on the ENBPs hold promise for water treatment, since iron NPs are commonly used in wastewater technologies that treat a wide variety of pollutants. Finally, the biological production of ENBP coupled to a biorefinery could become an environmentally friendly platform for nanomaterial biosynthesis as well as an additional source of revenues for a waste-based biorefinery.
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Affiliation(s)
- Leticia Romero-Cedillo
- Programa de Doctorado en Nanociencias y Nanotecnología, CINVESTAV del IPN, P.O. Box 17-740, 07000, Mexico City, Mexico
- Environmental Biotechnology and Renewable Energies Group, CINVESTAV del IPN, P.O. Box 14-740, 07000, Mexico City, Mexico
| | - Héctor M Poggi-Varaldo
- Programa de Doctorado en Nanociencias y Nanotecnología, CINVESTAV del IPN, P.O. Box 17-740, 07000, Mexico City, Mexico.
- Environmental Biotechnology and Renewable Energies Group, CINVESTAV del IPN, P.O. Box 14-740, 07000, Mexico City, Mexico.
| | - Jaime Santoyo-Salazar
- Programa de Doctorado en Nanociencias y Nanotecnología, CINVESTAV del IPN, P.O. Box 17-740, 07000, Mexico City, Mexico
| | - Carlos Escamilla-Alvarado
- Centre for Research on Biotechnology and Nanotechnology (CIByN), Faculty of Chemical Sciences, Engineering and Sustainable Bioprocesses Group, UANL, Parque de Investigación e Innovación Tecnológica, km 10 Autopista al Aeropuerto Internacional Mariano Escobedo, 66629, Apodaca, Nuevo León, Mexico
| | - Yasuhiro Matsumoto-Kuwabara
- Programa de Doctorado en Nanociencias y Nanotecnología, CINVESTAV del IPN, P.O. Box 17-740, 07000, Mexico City, Mexico
| | - M Teresa Ponce-Noyola
- Departamento de Biotecnología y Bioingeniería, CINVESTAV del IPN, Mexico City, Mexico
| | - Luz Bretón-Deval
- Cátedras Conacyt - Instituto de Biotecnología, UNAM, Av. Universidad 2001, Chamilpa, 62210, Cuernavaca, Morelos, Mexico
| | - Miguel García-Rocha
- Programa de Doctorado en Nanociencias y Nanotecnología, CINVESTAV del IPN, P.O. Box 17-740, 07000, Mexico City, Mexico
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10
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Fincker M, Huber JA, Orphan VJ, Rappé MS, Teske A, Spormann AM. Metabolic strategies of marine subseafloor Chloroflexi inferred from genome reconstructions. Environ Microbiol 2020; 22:3188-3204. [PMID: 32372496 DOI: 10.1111/1462-2920.15061] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 04/29/2020] [Accepted: 05/03/2020] [Indexed: 12/20/2022]
Abstract
Uncultured members of the Chloroflexi phylum are highly enriched in numerous subseafloor environments. Their metabolic potential was evaluated by reconstructing 31 Chloroflexi genomes from six different subseafloor habitats. The near ubiquitous presence of enzymes of the Wood-Ljungdahl pathway, electron bifurcation, and ferredoxin-dependent transport-coupled phosphorylation indicated anaerobic acetogenesis was central to their catabolism. Most of the genomes simultaneously contained multiple degradation pathways for complex carbohydrates, detrital protein, aromatic compounds, and hydrogen, indicating the coupling of oxidation of chemically diverse organic substrates to ubiquitous CO2 reduction. Such pathway combinations may confer a fitness advantage in subseafloor environments by enabling these Chloroflexi to act as primary fermenters and acetogens in one microorganism without the need for syntrophic H2 consumption. While evidence for catabolic oxygen respiration was limited to two phylogenetic clusters, the presence of genes encoding putative reductive dehalogenases throughout the phylum expanded the phylogenetic boundary for potential organohalide respiration past the Dehalococcoidia class.
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Affiliation(s)
- Maeva Fincker
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA
| | - Julie A Huber
- Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Victoria J Orphan
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Michael S Rappé
- Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI, USA
| | - Andreas Teske
- Department of Marine Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Alfred M Spormann
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA.,Department of Chemical Engineering, Stanford University, Stanford, CA, USA
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11
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Ang TF, Maiangwa J, Salleh AB, Normi YM, Leow TC. Dehalogenases: From Improved Performance to Potential Microbial Dehalogenation Applications. Molecules 2018; 23:E1100. [PMID: 29735886 PMCID: PMC6100074 DOI: 10.3390/molecules23051100] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/07/2018] [Accepted: 04/09/2018] [Indexed: 11/16/2022] Open
Abstract
The variety of halogenated substances and their derivatives widely used as pesticides, herbicides and other industrial products is of great concern due to the hazardous nature of these compounds owing to their toxicity, and persistent environmental pollution. Therefore, from the viewpoint of environmental technology, the need for environmentally relevant enzymes involved in biodegradation of these pollutants has received a great boost. One result of this great deal of attention has been the identification of environmentally relevant bacteria that produce hydrolytic dehalogenases—key enzymes which are considered cost-effective and eco-friendly in the removal and detoxification of these pollutants. These group of enzymes catalyzing the cleavage of the carbon-halogen bond of organohalogen compounds have potential applications in the chemical industry and bioremediation. The dehalogenases make use of fundamentally different strategies with a common mechanism to cleave carbon-halogen bonds whereby, an active-site carboxylate group attacks the substrate C atom bound to the halogen atom to form an ester intermediate and a halide ion with subsequent hydrolysis of the intermediate. Structurally, these dehalogenases have been characterized and shown to use substitution mechanisms that proceed via a covalent aspartyl intermediate. More so, the widest dehalogenation spectrum of electron acceptors tested with bacterial strains which could dehalogenate recalcitrant organohalides has further proven the versatility of bacterial dehalogenators to be considered when determining the fate of halogenated organics at contaminated sites. In this review, the general features of most widely studied bacterial dehalogenases, their structural properties, basis of the degradation of organohalides and their derivatives and how they have been improved for various applications is discussed.
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Affiliation(s)
- Thiau-Fu Ang
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
- Enzyme and Microbial Technology Research Centre, Centre of Excellence, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
| | - Jonathan Maiangwa
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
- Enzyme and Microbial Technology Research Centre, Centre of Excellence, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
| | - Abu Bakar Salleh
- Enzyme and Microbial Technology Research Centre, Centre of Excellence, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
- Institute of Bioscience, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
| | - Yahaya M Normi
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
- Enzyme and Microbial Technology Research Centre, Centre of Excellence, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
| | - Thean Chor Leow
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
- Enzyme and Microbial Technology Research Centre, Centre of Excellence, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
- Institute of Bioscience, University Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
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12
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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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13
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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: 56] [Impact Index Per Article: 8.0] [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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14
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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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15
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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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16
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Yang CW, Lee CC, Ku H, Chang BV. Bacterial communities associated with anaerobic debromination of decabromodiphenyl ether from mangrove sediment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:5391-5403. [PMID: 28013469 DOI: 10.1007/s11356-016-8259-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/13/2016] [Indexed: 06/06/2023]
Abstract
This study evaluated decabromodiphenyl ether (BDE-209) anaerobic debromination and bacterial community changes in mangrove sediment. BDE-209 debromination rates were enhanced with zerovalent iron compared to without zerovalent iron in the sediment. BDE-209 debromination rates in microcosms constructed with sediments collected in autumn were higher than in microcosms constructed with sediments collected in spring and were higher at the Bali sampling site than the Guandu sampling site. The intermediate products resulting from the reductive debromination of BDE-209 in sediment were nona-BDE (BDE-206, BDE-207), octa-BDEs (BDE-196, BDE-197), hepta-BDEs (BDE-183, BDE-184, BDE-191), hexa-BDEs (BDE-137, BDE-138, BDE-154, BDE-157), penta-BDEs (BDE-85, BDE-99, BDE-100, BDE-126), tetra-BDEs (BDE-47, BDE-49, BDE-66, BDE-77), tri-BDEs (BDE-17, BDE-28), and di-BDEs (BDE-15). Fifty bacterial genera associated with BDE-209 debromination were identified. Overall, 12 of the 50 bacterial genera were reported to be involved in dehalogenation of aromatic compounds. These bacteria have high potential to be BDE-209 debromination bacteria. Different combinations of bacterial community composition exhibit different abilities for BDE-209 anaerobic debromination.
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Affiliation(s)
- Chu-Wen Yang
- Department of Microbiology, Soochow University, Taipei, Taiwan
| | - Ching-Chang Lee
- Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - His Ku
- Department of Microbiology, Soochow University, Taipei, Taiwan
| | - Bea-Ven Chang
- Department of Microbiology, Soochow University, Taipei, Taiwan.
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17
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Jugder BE, Ertan H, Lee M, Manefield M, Marquis CP. Reductive Dehalogenases Come of Age in Biological Destruction of Organohalides. Trends Biotechnol 2015; 33:595-610. [DOI: 10.1016/j.tibtech.2015.07.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 07/27/2015] [Accepted: 07/30/2015] [Indexed: 11/28/2022]
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18
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Primers That Target Functional Genes of Organohalide-Respiring Bacteria. SPRINGER PROTOCOLS HANDBOOKS 2015. [DOI: 10.1007/8623_2015_75] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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19
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Krzmarzick MJ, Novak PJ. Removal of chlorinated organic compounds during wastewater treatment: achievements and limits. Appl Microbiol Biotechnol 2014; 98:6233-42. [DOI: 10.1007/s00253-014-5800-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/25/2014] [Accepted: 04/28/2014] [Indexed: 11/29/2022]
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20
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Kawai M, Futagami T, Toyoda A, Takaki Y, Nishi S, Hori S, Arai W, Tsubouchi T, Morono Y, Uchiyama I, Ito T, Fujiyama A, Inagaki F, Takami H. High frequency of phylogenetically diverse reductive dehalogenase-homologous genes in deep subseafloor sedimentary metagenomes. Front Microbiol 2014; 5:80. [PMID: 24624126 PMCID: PMC3939436 DOI: 10.3389/fmicb.2014.00080] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 02/13/2014] [Indexed: 02/01/2023] Open
Abstract
Marine subsurface sediments on the Pacific margin harbor diverse microbial communities even at depths of several hundreds meters below the seafloor (mbsf) or more. Previous PCR-based molecular analysis showed the presence of diverse reductive dehalogenase gene (rdhA) homologs in marine subsurface sediment, suggesting that anaerobic respiration of organohalides is one of the possible energy-yielding pathways in the organic-rich sedimentary habitat. However, primer-independent molecular characterization of rdhA has remained to be demonstrated. Here, we studied the diversity and frequency of rdhA homologs by metagenomic analysis of five different depth horizons (0.8, 5.1, 18.6, 48.5, and 107.0 mbsf) at Site C9001 off the Shimokita Peninsula of Japan. From all metagenomic pools, remarkably diverse rdhA-homologous sequences, some of which are affiliated with novel clusters, were observed with high frequency. As a comparison, we also examined frequency of dissimilatory sulfite reductase genes (dsrAB), key functional genes for microbial sulfate reduction. The dsrAB were also widely observed in the metagenomic pools whereas the frequency of dsrAB genes was generally smaller than that of rdhA-homologous genes. The phylogenetic composition of rdhA-homologous genes was similar among the five depth horizons. Our metagenomic data revealed that subseafloor rdhA homologs are more diverse than previously identified from PCR-based molecular studies. Spatial distribution of similar rdhA homologs across wide depositional ages indicates that the heterotrophic metabolic processes mediated by the genes can be ecologically important, functioning in the organic-rich subseafloor sedimentary biosphere.
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Affiliation(s)
- Mikihiko Kawai
- Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Nankoku, Japan ; Microbial Genome Research Group, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Yokosuka, Japan
| | - Taiki Futagami
- Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Nankoku, Japan ; Department of Bioscience and Biotechnology, Kyushu University Fukuoka, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, Center for Information Biology, National Institute of Genetics Mishima, Japan
| | - Yoshihiro Takaki
- Microbial Genome Research Group, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Yokosuka, Japan
| | - Shinro Nishi
- Microbial Genome Research Group, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Yokosuka, Japan
| | - Sayaka Hori
- Microbial Genome Research Group, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Yokosuka, Japan
| | - Wataru Arai
- Microbial Genome Research Group, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Yokosuka, Japan
| | - Taishi Tsubouchi
- Microbial Genome Research Group, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Yokosuka, Japan
| | - Yuki Morono
- Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Nankoku, Japan ; Geobio-Engineering and Technology Group, Submarine Resources Research Project, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Nankoku, Japan
| | - Ikuo Uchiyama
- National Institute for Basic Biology, National Institutes of Natural Sciences Okazaki, Japan ; Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies Okazaki, Japan
| | - Takehiko Ito
- Department of Biological Sciences, Tokyo Institute of Technology Yokohama, Japan
| | - Asao Fujiyama
- Comparative Genomics Laboratory, Center for Information Biology, National Institute of Genetics Mishima, Japan
| | - Fumio Inagaki
- Geomicrobiology Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Nankoku, Japan ; Geobio-Engineering and Technology Group, Submarine Resources Research Project, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Nankoku, Japan
| | - Hideto Takami
- Microbial Genome Research Group, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Yokosuka, Japan
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21
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Novel Firmicutes group implicated in the dechlorination of two chlorinated xanthones, analogues of natural organochlorines. Appl Environ Microbiol 2013; 80:1210-8. [PMID: 24296507 DOI: 10.1128/aem.03472-13] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Although the abundance and diversity of natural organochlorines are well established, much is still unknown about the degradation of these compounds. Triplicate microcosms were used to determine whether, and which, bacterial communities could dechlorinate two chlorinated xanthones (2,7-dichloroxanthone and 5,7-dichloro-1,3-dihydroxylxanthone), analogues of a diverse class of natural organochlorines. According to quantitative-PCR (qPCR) results, several known dechlorinating genera were either not present or not enriched during dechlorination of the xanthones. Denaturing gradient gel electrophoresis, however, indicated that several Firmicutes were enriched in the dechlorinating cultures compared to triplicate controls amended with nonchlorinated xanthones. One such group, herein referred to as the Gopher group, was further studied with a novel qPCR method that confirmed enrichment of Gopher group 16S rRNA genes in the dechlorinating cultures. The enrichment of the Gopher group was again tested with two new sets of triplicate microcosms. Enrichment was observed during chlorinated xanthone dechlorination in one set of these triplicate microcosms. In the other set, two microcosms showed clear enrichment while a third did not. The Gopher group is a previously unidentified group of Firmicutes, distinct from but related to the Dehalobacter and Desulfitobacterium genera; this group also contains clones from at least four unique cultures capable of dechlorinating anthropogenic organochlorines that have been previously described in the literature. This study suggests that natural chlorinated xanthones may be effective biostimulants to enhance the remediation of pollutants and highlights the idea that novel genera of dechlorinators likely exist and may be active in bioremediation and the natural cycling of chlorine.
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Leys D, Adrian L, Smidt H. Organohalide respiration: microbes breathing chlorinated molecules. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120316. [PMID: 23479746 DOI: 10.1098/rstb.2012.0316] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Bacterial respiration has taken advantage of almost every redox couple present in the environment. The reduction of organohalide compounds to release the reduced halide ion drives energy production in organohalide respiring bacteria. This process is centred around the reductive dehalogenases, an iron-sulfur and corrinoid containing family of enzymes. These enzymes, transcriptional regulators and the bacteria themselves have potential to contribute to future bioremediation solutions that address the pollution of the environment by halogenated organic compounds.
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Affiliation(s)
- David Leys
- Manchester Institute of Biotechnology, University of Manchester, MIB 131 Princess Street, Manchester, UK.
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