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Bulka O, Picott K, Mahadevan R, Edwards EA. From mec cassette to rdhA: a key Dehalobacter genomic neighborhood in a chloroform and dichloromethane-transforming microbial consortium. Appl Environ Microbiol 2024; 90:e0073224. [PMID: 38819127 PMCID: PMC11218628 DOI: 10.1128/aem.00732-24] [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] [Received: 04/16/2024] [Accepted: 05/20/2024] [Indexed: 06/01/2024] Open
Abstract
Chloroform (CF) and dichloromethane (DCM) are groundwater contaminants of concern due to their high toxicity and inhibition of important biogeochemical processes such as methanogenesis. Anaerobic biotransformation of CF and DCM has been well documented but typically independently of one another. CF is the electron acceptor for certain organohalide-respiring bacteria that use reductive dehalogenases (RDases) to dechlorinate CF to DCM. In contrast, known DCM degraders use DCM as their electron donor, which is oxidized using a series of methyltransferases and associated proteins encoded by the mec cassette to facilitate the entry of DCM to the Wood-Ljungdahl pathway. The SC05 culture is an enrichment culture sold commercially for bioaugmentation, which transforms CF via DCM to CO2. This culture has the unique ability to dechlorinate CF to DCM using electron equivalents provided by the oxidation of DCM to CO2. Here, we use metagenomic and metaproteomic analyses to identify the functional genes involved in each of these transformations. Though 91 metagenome-assembled genomes were assembled, the genes for an RDase-named acdA-and a complete mec cassette were found to be encoded on a single contig belonging to Dehalobacter. AcdA and critical Mec proteins were also highly expressed by the culture. Heterologously expressed AcdA dechlorinated CF and other chloroalkanes but had 100-fold lower activity on DCM. Overall, the high expression of Mec proteins and the activity of AcdA suggest a Dehalobacter capable of dechlorination of CF to DCM and subsequent mineralization of DCM using the mec cassette. IMPORTANCE Chloroform (CF) and dichloromethane (DCM) are regulated groundwater contaminants. A cost-effective approach to remove these pollutants from contaminated groundwater is to employ microbes that transform CF and DCM as part of their metabolism, thus depleting the contamination as the microbes continue to grow. In this work, we investigate bioaugmentation culture SC05, a mixed microbial consortium that effectively and simultaneously degrades both CF and DCM coupled to the growth of Dehalobacter. We identified the functional genes responsible for the transformation of CF and DCM in SC05. These genetic biomarkers provide a means to monitor the remediation process in the field.
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Affiliation(s)
- Olivia Bulka
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Katherine Picott
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Elizabeth A. Edwards
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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Chen G, Yang Y, Yan J, Löffler FE. Metabolite cross-feeding enables concomitant catabolism of chlorinated methanes and chlorinated ethenes in synthetic microbial assemblies. THE ISME JOURNAL 2024; 18:wrae090. [PMID: 38818735 PMCID: PMC11170663 DOI: 10.1093/ismejo/wrae090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 04/19/2024] [Accepted: 05/21/2024] [Indexed: 06/01/2024]
Abstract
Isolate studies have been a cornerstone for unraveling metabolic pathways and phenotypical (functional) features. Biogeochemical processes in natural and engineered ecosystems are generally performed by more than a single microbe and often rely on mutualistic interactions. We demonstrate the rational bottom-up design of synthetic, interdependent co-cultures to achieve concomitant utilization of chlorinated methanes as electron donors and organohalogens as electron acceptors. Specialized anaerobes conserve energy from the catabolic conversion of chloromethane or dichloromethane to formate, H2, and acetate, compounds that the organohalide-respiring bacterium Dehalogenimonas etheniformans strain GP requires to utilize cis-1,2-dichloroethenene and vinyl chloride as electron acceptors. Organism-specific qPCR enumeration matched the growth of individual dechlorinators to the respective functional (i.e. dechlorination) traits. The metabolite cross-feeding in the synthetic (co-)cultures enables concomitant utilization of chlorinated methanes (i.e. chloromethane and dichloromethane) and chlorinated ethenes (i.e. cis-1,2-dichloroethenene and vinyl chloride) without the addition of an external electron donor (i.e. formate and H2). The findings illustrate that naturally occurring chlorinated C1 compounds can sustain anaerobic food webs, an observation with implications for the development of interdependent, mutualistic communities, the sustenance of microbial life in oligotrophic and energy-deprived environments, and the fate of chloromethane/dichloromethane and chlorinated electron acceptors (e.g. chlorinated ethenes) in pristine environments and commingled contaminant plumes.
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Affiliation(s)
- Gao Chen
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996, United States
| | - Yi Yang
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning 110016, China
| | - Jun Yan
- Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning 110016, China
| | - Frank E Löffler
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996, United States
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, United States
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN 37996, United States
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Tucci M, Fernández-Verdejo D, Resitano M, Ciacia P, Guisasola A, Blánquez P, Marco-Urrea E, Cruz Viggi C, Matturro B, Crognale S, Aulenta F. Toluene-driven anaerobic biodegradation of chloroform in a continuous-flow bioelectrochemical reactor. CHEMOSPHERE 2023; 338:139467. [PMID: 37437617 DOI: 10.1016/j.chemosphere.2023.139467] [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: 03/31/2023] [Revised: 06/12/2023] [Accepted: 07/09/2023] [Indexed: 07/14/2023]
Abstract
Subsurface co-contamination by multiple pollutants can be challenging for the design of bioremediation strategies since it may require promoting different and often antagonistic degradation pathways. Here, we investigated the simultaneous degradation of toluene and chloroform (CF) in a continuous-flow anaerobic bioelectrochemical reactor. As a result, 47 μmol L-1 d-1 of toluene and 60 μmol L-1 d-1 of CF were concurrently removed, when the anode was polarized at +0.4 V vs. Standard Hydrogen Electrode (SHE). Analysis of the microbial community structure and key functional genes allowed to identify the involved degradation pathways. Interestingly, when acetate was supplied along with toluene, to simulate the impact of a readily biodegradable substrate on process performance, toluene degradation was adversely affected, likely due to competitive inhibition effects. Overall, this study proved the efficacy of the developed bioelectrochemical system in simultaneously treating multiple groundwater contaminants, paving the way for the application in real-world scenarios.
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Affiliation(s)
- Matteo Tucci
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km 29.300, 00015, Monterotondo, RM, Italy
| | - David Fernández-Verdejo
- Biorem UAB, Department of Chemical, Biological and Environmental Engineering, School of Engineering, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Marco Resitano
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km 29.300, 00015, Monterotondo, RM, Italy
| | - Pamela Ciacia
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km 29.300, 00015, Monterotondo, RM, Italy
| | - Albert Guisasola
- GENOCOV, Department of Chemical, Biological and Environmental Engineering, School of Engineering, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Paqui Blánquez
- Biorem UAB, Department of Chemical, Biological and Environmental Engineering, School of Engineering, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Ernest Marco-Urrea
- Biorem UAB, Department of Chemical, Biological and Environmental Engineering, School of Engineering, Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain
| | - Carolina Cruz Viggi
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km 29.300, 00015, Monterotondo, RM, Italy
| | - Bruna Matturro
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km 29.300, 00015, Monterotondo, RM, Italy; National Biodiversity Future Center (NBFC), Palermo, Italy
| | - Simona Crognale
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km 29.300, 00015, Monterotondo, RM, Italy; National Biodiversity Future Center (NBFC), Palermo, Italy
| | - Federico Aulenta
- Water Research Institute (IRSA), National Research Council (CNR), Via Salaria km 29.300, 00015, Monterotondo, RM, Italy; National Biodiversity Future Center (NBFC), Palermo, Italy.
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Wasmund K, Trueba-Santiso A, Vicent T, Adrian L, Vuilleumier S, Marco-Urrea E. Proteogenomics of the novel Dehalobacterium formicoaceticum strain EZ94 highlights a key role of methyltransferases during anaerobic dichloromethane degradation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:80602-80612. [PMID: 37300728 PMCID: PMC10344839 DOI: 10.1007/s11356-023-28144-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 06/02/2023] [Indexed: 06/12/2023]
Abstract
Dichloromethane (DCM, methylene chloride) is a toxic, high-volume industrial pollutant of long-standing. Anaerobic biodegradation is crucial for its removal from contaminated environments, yet prevailing mechanisms remain unresolved, especially concerning dehalogenation. In this study, we obtained an assembled genome of a novel DCM-degrading strain, Dehalobacterium formicoaceticum strain EZ94, from a stable DCM-degrading consortium, and we analyzed its proteome during degradation of DCM. A gene cluster recently predicted to play a major role in anaerobic DCM catabolism (the mec cassette) was found. Methyltransferases and other proteins encoded by the mec cassette were among the most abundant proteins produced, suggesting their involvement in DCM catabolism. Reductive dehalogenases were not detected. Genes and corresponding proteins for a complete Wood-Ljungdahl pathway, which could enable further metabolism of DCM carbon, were also found. Unlike for the anaerobic DCM degrader "Ca. F. warabiya," no genes for metabolism of the quaternary amines choline and glycine betaine were identified. This work provides independent and supporting evidence that mec-associated methyltransferases are key to anaerobic DCM metabolism.
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Affiliation(s)
- Kenneth Wasmund
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- School of Biological Sciences, University of Portsmouth, Portsmouth, UK
| | - Alba Trueba-Santiso
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, 08193, Cerdanyola del Valles, Spain
- Current address: Department of Chemical Engineering, CRETUS Institute, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Galicia, Spain
| | - Teresa Vicent
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, 08193, Cerdanyola del Valles, Spain
| | - Lorenz Adrian
- Department Environmental Biotechnology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
- Chair for Geobiotechnology, Technische Universität Berlin, Berlin, Germany
| | - Stéphane Vuilleumier
- Université de Strasbourg, CNRS, GMGM UMR 7156, Génétique Moléculaire, Génomique, Microbiologie, Strasbourg, France
| | - Ernest Marco-Urrea
- Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Carrer de les Sitges s/n, 08193, Cerdanyola del Valles, Spain.
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Holland SI, Vázquez-Campos X, Ertan H, Edwards RJ, Manefield MJ, Lee M. Metaproteomics reveals methyltransferases implicated in dichloromethane and glycine betaine fermentation by ' Candidatus Formimonas warabiya' strain DCMF. Front Microbiol 2022; 13:1035247. [PMID: 36569084 PMCID: PMC9768040 DOI: 10.3389/fmicb.2022.1035247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 11/15/2022] [Indexed: 12/12/2022] Open
Abstract
Dichloromethane (DCM; CH2Cl2) is a widespread pollutant with anthropogenic and natural sources. Anaerobic DCM-dechlorinating bacteria use the Wood-Ljungdahl pathway, yet dechlorination reaction mechanisms remain unclear and the enzyme(s) responsible for carbon-chlorine bond cleavage have not been definitively identified. Of the three bacterial taxa known to carry out anaerobic dechlorination of DCM, 'Candidatus Formimonas warabiya' strain DCMF is the only organism that can also ferment non-chlorinated substrates, including quaternary amines (i.e., choline and glycine betaine) and methanol. Strain DCMF is present within enrichment culture DFE, which was derived from an organochlorine-contaminated aquifer. We utilized the metabolic versatility of strain DCMF to carry out comparative metaproteomics of cultures grown with DCM or glycine betaine. This revealed differential abundance of numerous proteins, including a methyltransferase gene cluster (the mec cassette) that was significantly more abundant during DCM degradation, as well as highly conserved amongst anaerobic DCM-degrading bacteria. This lends strong support to its involvement in DCM dechlorination. A putative glycine betaine methyltransferase was also discovered, adding to the limited knowledge about the fate of this widespread osmolyte in anoxic subsurface environments. Furthermore, the metagenome of enrichment culture DFE was assembled, resulting in five high quality and two low quality draft metagenome-assembled genomes. Metaproteogenomic analysis did not reveal any genes or proteins for utilization of DCM or glycine betaine in the cohabiting bacteria, supporting the previously held idea that they persist via necromass utilization.
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Affiliation(s)
- Sophie I. Holland
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Xabier Vázquez-Campos
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Haluk Ertan
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, Australia,Department of Molecular Biology and Genetics, Istanbul University, Istanbul, Turkey
| | - Richard J. Edwards
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Michael J. Manefield
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia,School of Chemical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Matthew Lee
- Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia,*Correspondence: Matthew Lee,
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Duan Y, Liu P, Lin F, He Y, Zhu Y, Wang Z. Catalytic ozonation of dichloromethane at low temperature and even room temperature on Mn-loaded catalysts. RSC Adv 2022; 12:33429-33439. [PMID: 36425204 PMCID: PMC9679731 DOI: 10.1039/d2ra05828f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/14/2022] [Indexed: 11/23/2022] Open
Abstract
Five Mn-loaded catalysts were synthesized on γ-Al2O3, TiO2, ZrO2, nano γ-Al2O3 and nanoZrO2 supports. The catalytic ozonation of DCM (dichloromethane) was evaluated under industrial conditions (i.e., temperature, O3 input, H2O and SO2 content). According to results, >90% DCM conversion without O3 residue was achieved for all samples at 120 °C and an O3/DCM ratio of 6. At 20–120 °C, the highest Mn3+ content, abundant surface oxygen species and more weak acid sites led to the best performance of Mn/nanoAl2O3 (M/A-II). At 20 °C and 120 °C, 80% and 95% DCM can be degraded respectively on M/A-II at 20 °C with matched surface oxygen species and acidity. An O3/DCM ratio of 6 was optimal for performance and economy. For the effects of complex exhaust, both H2O and SO2 deactivated M/A-II. The H2O-induced deactivation was recoverable and also removed surface-deposited chlorine-containing species, enhancing the HCl selectivity. Finally, the Cl equilibrium of the reaction was comprehensively analyzed. The collaboration of abundant surface oxygen species and weak acid sites at low temperatures ensures the best functioning of M/A-II.![]()
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Affiliation(s)
- Yaxin Duan
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, P. R. China
| | - Peixi Liu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, P. R. China
| | - Fawei Lin
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, P. R. China
| | - Yong He
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, P. R. China
| | - Yanqun Zhu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, P. R. China
| | - Zhihua Wang
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, P. R. China
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