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Wu M, Li J, Lai CY, Leu AO, Sun S, Gu R, Erler DV, Liu L, Li L, Tyson GW, Yuan Z, McIlroy SJ, Guo J. Nitrate-driven anaerobic oxidation of ethane and butane by bacteria. THE ISME JOURNAL 2024; 18:wrad011. [PMID: 38365228 PMCID: PMC10811727 DOI: 10.1093/ismejo/wrad011] [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: 11/06/2023] [Revised: 11/15/2023] [Accepted: 11/15/2023] [Indexed: 02/18/2024]
Abstract
The short-chain gaseous alkanes (ethane, propane, and butane; SCGAs) are important components of natural gas, yet their fate in environmental systems is poorly understood. Microbially mediated anaerobic oxidation of SCGAs coupled to nitrate reduction has been demonstrated for propane, but is yet to be shown for ethane or butane-despite being energetically feasible. Here we report two independent bacterial enrichments performing anaerobic ethane and butane oxidation, respectively, coupled to nitrate reduction to dinitrogen gas and ammonium. Isotopic 13C- and 15N-labelling experiments, mass and electron balance tests, and metabolite and meta-omics analyses collectively reveal that the recently described propane-oxidizing "Candidatus Alkanivorans nitratireducens" was also responsible for nitrate-dependent anaerobic oxidation of the SCGAs in both these enrichments. The complete genome of this species encodes alkylsuccinate synthase genes for the activation of ethane/butane via fumarate addition. Further substrate range tests confirm that "Ca. A. nitratireducens" is metabolically versatile, being able to degrade ethane, propane, and butane under anoxic conditions. Moreover, our study proves nitrate as an additional electron sink for ethane and butane in anaerobic environments, and for the first time demonstrates the use of the fumarate addition pathway in anaerobic ethane oxidation. These findings contribute to our understanding of microbial metabolism of SCGAs in anaerobic environments.
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Affiliation(s)
- Mengxiong Wu
- Australian Centre for Water and Environmental Biotechnology, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Jie Li
- Australian Centre for Water and Environmental Biotechnology, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Chun-Yu Lai
- Australian Centre for Water and Environmental Biotechnology, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, St Lucia, Queensland 4072, Australia
- College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China
| | - Andy O Leu
- Centre for Microbiome Research, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology (QUT), Woolloongabba, Queensland, Australia
| | - Shengjie Sun
- Computational Science Program, The University of Texas at El Paso, El Paso, TX, United States
| | - Rui Gu
- Australian Centre for Water and Environmental Biotechnology, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Dirk V Erler
- Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia
| | - Lian Liu
- Metabolomics Australia (Queensland Node), Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Lin Li
- Department of Physics, University of Texas at El Paso, El Paso, TX, United States
| | - Gene W Tyson
- Centre for Microbiome Research, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology (QUT), Woolloongabba, Queensland, Australia
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, St Lucia, Queensland 4072, Australia
- School of Energy and Environment, City University of Hong Kong, Hong Kong SAR, China
| | - Simon J McIlroy
- Centre for Microbiome Research, School of Biomedical Sciences, Translational Research Institute, Queensland University of Technology (QUT), Woolloongabba, Queensland, Australia
| | - Jianhua Guo
- Australian Centre for Water and Environmental Biotechnology, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, St Lucia, Queensland 4072, Australia
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2
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Edgcomb VP, Teske AP, Mara P. Microbial Hydrocarbon Degradation in Guaymas Basin-Exploring the Roles and Potential Interactions of Fungi and Sulfate-Reducing Bacteria. Front Microbiol 2022; 13:831828. [PMID: 35356530 PMCID: PMC8959706 DOI: 10.3389/fmicb.2022.831828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/04/2022] [Indexed: 11/13/2022] Open
Abstract
Hydrocarbons are degraded by specialized types of bacteria, archaea, and fungi. Their occurrence in marine hydrocarbon seeps and sediments prompted a study of their role and their potential interactions, using the hydrocarbon-rich hydrothermal sediments of Guaymas Basin in the Gulf of California as a model system. This sedimented vent site is characterized by localized hydrothermal circulation that introduces seawater sulfate into methane- and hydrocarbon-rich sediments, and thus selects for diverse hydrocarbon-degrading communities of which methane, alkane- and aromatics-oxidizing sulfate-reducing bacteria and archaea have been especially well-studied. Current molecular and cultivation surveys are detecting diverse fungi in Guaymas Basin hydrothermal sediments, and draw attention to possible fungal-bacterial interactions. In this Hypothesis and Theory article, we report on background, recent results and outcomes, and underlying hypotheses that guide current experiments on this topic in the Edgcomb and Teske labs in 2021, and that we will revisit during our ongoing investigations of bacterial, archaeal, and fungal communities in the deep sedimentary subsurface of Guaymas Basin.
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Affiliation(s)
| | - Andreas P. Teske
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Paraskevi Mara
- Woods Hole Oceanographic Institution, Woods Hole, MA, United States
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3
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Yang Z, Liu Z, Dabrowska M, Debiec-Andrzejewska K, Stasiuk R, Yin H, Drewniak L. Biostimulation of sulfate-reducing bacteria used for treatment of hydrometallurgical waste by secondary metabolites of urea decomposition by Ochrobactrum sp. POC9: From genome to microbiome analysis. CHEMOSPHERE 2021; 282:131064. [PMID: 34118631 DOI: 10.1016/j.chemosphere.2021.131064] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 04/25/2021] [Accepted: 05/28/2021] [Indexed: 06/12/2023]
Abstract
Sulfate-reducing bacteria (SRB) are key players in many passive and active systems dedicated to the treatment of hydrometallurgical leachates. One of the main factors reducing the efficiency and activity of SRB is the low pH and poor nutrients in leachates. We propose an innovative solution utilizing biogenic ammonia (B-NH3), produced by urea degrading bacteria, as a pretreatment agent for increasing the pH of the leachate and spontaneously stimulating SRB activity via bacterial secondary metabolites. The selected strain, Ochrobactrum sp. POC9, generated 984.7 mg/L of ammonia in 24 h and promotes an effective neutralization of B-NH3. The inferred metabolic traits indicated that the Ochrobactrum sp. POC9 can synthesize a group of vitamins B, and the production of various organic metabolites was confirmed by GC-MS analysis. These metabolites comprise alcohols, organic acids, and unsaturated hydrocarbons that may stimulate biological sulfate reduction. With the pretreatment of B-NH3, sulfate removal efficiency reached ~92.3% after 14 days of incubation, whereas SRB cell count and abundance were boosted (~107 cell counts and 88 OTUs of SRB) compared to synthetic ammonia (S-NH3) (~103 cell counts and 40 OTUs of SRB). The dominant SRB is Desulfovibrio in both S-NH3 and B-NH3 pretreated leachate, however, it belonged to two different clades. By reconstructing the ecological network, we found that B-NH3 not only directly increases SRB performance but also promotes other strains with positive correlations with SRB.
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Affiliation(s)
- Zhendong Yang
- Institute of Microbiology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland
| | - Zhenghua Liu
- Central South University, School of Resource Processing and Bioengineering, No. 932 Lushan South Road, Changsha, China
| | - Maria Dabrowska
- Institute of Microbiology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland
| | - Klaudia Debiec-Andrzejewska
- Institute of Microbiology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland
| | - Robert Stasiuk
- Institute of Microbiology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland
| | - Huaqun Yin
- Central South University, School of Resource Processing and Bioengineering, No. 932 Lushan South Road, Changsha, China
| | - Lukasz Drewniak
- Institute of Microbiology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland.
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4
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Adam N, Han Y, Laufer-Meiser K, Bährle R, Schwarz-Schampera U, Schippers A, Perner M. Deltaproteobacterium Strain KaireiS1, a Mesophilic, Hydrogen-Oxidizing and Sulfate-Reducing Bacterium From an Inactive Deep-Sea Hydrothermal Chimney. Front Microbiol 2021; 12:686276. [PMID: 34630341 PMCID: PMC8494109 DOI: 10.3389/fmicb.2021.686276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 08/24/2021] [Indexed: 11/13/2022] Open
Abstract
A novel deltaproteobacterial, mesophilic, hydrogen-oxidizing, and sulfate-reducing bacterium (strain KaireiS1) was highly enriched from an inactive chimney located in the active zone of the Kairei hydrothermal vent field (Central Indian Ridge) in the Indian Ocean. Based on 16S rRNA gene analyses, strain KaireiS1 is the currently only cultured representative of a cluster of uncultured Deltaproteobacteria, positioned within the Desulfobulbaceae family, between the Desulfobulbus genus and the “Cable Bacteria.” A facultative autotrophic lifestyle of KaireiS1 is indicated by its growth in the absence of organic compounds, measurements of CO2-fixation rates, and activity measurements of carbon monoxide dehydrogenase, the key enzyme of the reductive Acetyl-CoA pathway. Apart from hydrogen, strain KaireiS1 can also use propionate, lactate, and pentadecane as electron donors. However, the highest cell numbers were reached when grown autotrophically with molecular hydrogen. Hydrogen uptake activity was found in membrane and soluble fractions of cell-free extracts and reached up to 2,981±129 nmol H2*min−1*mg−1 of partially purified protein. Commonly, autotrophic sulfate-reducing bacteria from the Deltaproteobacteria class, thriving in hydrothermal vent habitats are described as thermophiles. Given its physiological characteristics and specific isolation source, strain KaireiS1 demonstrates a previously unnoticed potential for microbial sulfate reduction by autotrophs taking place at moderate temperatures in hydrothermal vent fields.
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Affiliation(s)
- Nicole Adam
- GEOMAR and Molecular Biology of Microbial Consortia, GEOMAR Helmholtz Center for Ocean Research Kiel, Kiel, Germany
| | - Yuchen Han
- GEOMAR and Molecular Biology of Microbial Consortia, Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany.,Microbiology and Biotechnology, Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
| | - Katja Laufer-Meiser
- GEOMAR and Molecular Biology of Microbial Consortia, GEOMAR Helmholtz Center for Ocean Research Kiel, Kiel, Germany
| | - Rebecca Bährle
- GEOMAR and Molecular Biology of Microbial Consortia, GEOMAR Helmholtz Center for Ocean Research Kiel, Kiel, Germany
| | - Ulrich Schwarz-Schampera
- Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany.,International Seabed Authority, Kingston, Jamaica
| | - Axel Schippers
- Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany
| | - Mirjam Perner
- GEOMAR and Molecular Biology of Microbial Consortia, GEOMAR Helmholtz Center for Ocean Research Kiel, Kiel, Germany.,GEOMAR and Molecular Biology of Microbial Consortia, Biocenter Klein Flottbek, University of Hamburg, Hamburg, Germany
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5
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Kharey G, Scheffer G, Gieg LM. Combined Use of Diagnostic Fumarate Addition Metabolites and Genes Provides Evidence for Anaerobic Hydrocarbon Biodegradation in Contaminated Groundwater. Microorganisms 2020; 8:microorganisms8101532. [PMID: 33036175 PMCID: PMC7599786 DOI: 10.3390/microorganisms8101532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 09/28/2020] [Accepted: 09/28/2020] [Indexed: 12/05/2022] Open
Abstract
The widespread use of hydrocarbon-based fuels has led to the contamination of many natural environments due to accidental spills or leaks. While anaerobic microorganisms indigenous to many fuel-contaminated groundwater sites can play a role in site remediation (e.g., monitored natural attenuation, MNA) via hydrocarbon biodegradation, multiple lines of evidence in support of such bioremediation are required. In this study, we investigated two fuel-contaminated groundwater sites for their potential to be managed by MNA. Microbial community composition, biogeochemical indicators, fumarate addition metabolites, and genes diagnostic of both alkane and alkyl-monoaromatic hydrocarbon activation were assessed. Fumarate addition metabolites and catabolic genes were detected for both classes of hydrocarbon biodegradation at both sites, providing strong evidence for in situ anaerobic hydrocarbon biodegradation. However, relevant metabolites and genes did not consistently co-occur within all groundwater samples. Using newly designed mixtures of quantitative polymerase chain reaction (qPCR) primers to target diverse assA and bssA genes, we measured assA gene abundances ranging from 105–108 copies/L, and bssA gene abundances ranging from 105–1010 copies/L at the sites. Overall, this study demonstrates the value of investigating fuel-contaminated sites using both metabolites and genes diagnostic of anaerobic hydrocarbon biodegradation for different classes of hydrocarbons to help assess field sites for management by MNA.
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6
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Zamanpour MK, Kaliappan RS, Rockne KJ. Gas ebullition from petroleum hydrocarbons in aquatic sediments: A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 271:110997. [PMID: 32778285 DOI: 10.1016/j.jenvman.2020.110997] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 05/19/2020] [Accepted: 06/21/2020] [Indexed: 06/11/2023]
Abstract
Gas ebullition in sediment results from biogenic gas production by mixtures of bacteria and archaea. It often occurs in organic-rich sediments that have been impacted by petroleum hydrocarbon (PHC) and other anthropogenic pollution. Ebullition occurs under a relatively narrow set of biological, chemical, and sediment geomechanical conditions. This process occurs in three phases: I) biogenic production of primarily methane and dissolved phase transport of the gases in the pore water to a bubble nucleation site, II) bubble growth and sediment fracture, and III) bubble rise to the surface. The rate of biogenic gas production in phase I and the resistance of the sediment to gas fracture in phase II play the most significant roles in ebullition kinetics. What is less understood is the role that substrate structure plays in the rate of methanogenesis that drives gas ebullition. It is well established that methanogens have a very restricted set of compounds that can serve as substrates, so any complex organic molecule must first be broken down to fermentable compounds. Given that most ebullition-active sediments are completely anaerobic, the well-known difficulty in degrading PHCs under anaerobic conditions suggests potential limitations on PHC-derived gas ebullition. To date, there are no studies that conclusively demonstrate that weathered PHCs can alone drive gas ebullition. This review consists of an overview of the factors affecting gas ebullition and the biochemistry of anaerobic PHC biodegradation and methanogenesis in sediment systems. We next compile results from the scholarly literature on PHCs serving as a source of methanogenesis. We combine these results to assess the potential for PHC-driven gas ebullition using energetics, kinetics, and sediment geomechanics analyses. The results suggest that short chain <C10 alkanes are the only PHC class that alone may have the potential to drive ebullition, and that PHC-derived methanogenesis likely plays a minor part in driving gas ebullition in contaminated sediments compared to natural organic matter.
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Affiliation(s)
| | - Raja Shankar Kaliappan
- Department of Civil and Materials Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Karl John Rockne
- Department of Civil and Materials Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA.
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7
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Chen J, Liu YF, Zhou L, Irfan M, Hou ZW, Li W, Mbadinga SM, Liu JF, Yang SZ, Wu XL, Gu JD, Mu BZ. Long-chain n-alkane biodegradation coupling to methane production in an enriched culture from production water of a high-temperature oil reservoir. AMB Express 2020; 10:63. [PMID: 32266503 PMCID: PMC7138878 DOI: 10.1186/s13568-020-00998-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 03/21/2020] [Indexed: 11/18/2022] Open
Abstract
Paraffinic n-alkanes (C22–C30), crucial portions of residual oil, are generally considered to be difficult to be biodegraded owing to their general solidity at ambient temperatures and low water solubility, rendering relatively little known about metabolic processes in different methanogenic hydrocarbon-contaminated environments. Here, we established a methanogenic C22–C30 n-alkane-degrading enrichment culture derived from a high-temperature oil reservoir production water. During two-year incubation (736 days), unexpectedly significant methane production was observed. The measured maximum methane yield rate (164.40 μmol L−1 d−1) occurred during the incubation period from day 351 to 513. The nearly complete consumption (> 97%) of paraffinic n-alkanes and the detection of dicarboxylic acids in n-alkane-amended cultures indicated the biotransformation of paraffin to methane under anoxic condition. 16S rRNA gene analysis suggested that the dominant methanogen in n-alkane-degrading cultures shifted from Methanothermobacter on day 322 to Thermoplasmatales on day 736. Bacterial community analysis based on high-throughput sequencing revealed that members of Proteobacteria and Firmicutes exhibiting predominant in control cultures, while microorganisms affiliated with Actinobacteria turned into the most dominant phylum in n-alkane-dependent cultures. Additionally, the relative abundance of mcrA gene based on genomic DNA significantly increased over the incubation time, suggesting an important role of methanogens in these consortia. This work extends our understanding of methanogenic paraffinic n-alkanes conversion and has biotechnological implications for microbial enhanced recovery of residual hydrocarbons and effective bioremediation of hydrocarbon-containing biospheres.
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8
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Liang R, Davidova I, Hirano SI, Duncan KE, Suflita JM. Community succession in an anaerobic long-chain paraffin-degrading consortium and impact on chemical and electrical microbially influenced iron corrosion. FEMS Microbiol Ecol 2019; 95:5529450. [DOI: 10.1093/femsec/fiz111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 07/06/2019] [Indexed: 11/12/2022] Open
Abstract
ABSTRACT
Community compositional changes and the corrosion of carbon steel in the presence of different electron donor and acceptor combinations were examined with a methanogenic consortium enriched for its ability to mineralize paraffins. Despite cultivation in the absence of sulfate, metagenomic analysis revealed the persistence of several sulfate-reducing bacterial taxa. Upon sulfate amendment, the consortium was able to couple C28H58 biodegradation with sulfate reduction. Comparative analysis suggested that Desulforhabdus and/or Desulfovibrio likely supplanted methanogens as syntrophic partners needed for C28H58 mineralization. Further enrichment in the absence of a paraffin revealed that the consortium could also utilize carbon steel as a source of electrons. The severity of both general and localized corrosion increased in the presence of sulfate, regardless of the electron donor utilized. With carbon steel as an electron donor, Desulfobulbus dominated in the consortium and electrons from iron accounted for ∼92% of that required for sulfate reduction. An isolated Desulfovibrio spp. was able to extract electrons from iron and accelerate corrosion. Thus, hydrogenotrophic partner microorganisms required for syntrophic paraffin metabolism can be readily substituted depending on the availability of an external electron acceptor and a single paraffin-degrading consortium harbored microbes capable of both chemical and electrical microbially influenced iron corrosion.
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Affiliation(s)
- Renxing Liang
- Department of Microbiology and Plant Biology, Institute for Energy and the Environment, University of Oklahoma, Norman, OK 73019, USA
| | - Irene Davidova
- Department of Microbiology and Plant Biology, Institute for Energy and the Environment, University of Oklahoma, Norman, OK 73019, USA
| | - Shin-ichi Hirano
- Department of Microbiology and Plant Biology, Institute for Energy and the Environment, University of Oklahoma, Norman, OK 73019, USA
| | - Kathleen E Duncan
- Department of Microbiology and Plant Biology, Institute for Energy and the Environment, University of Oklahoma, Norman, OK 73019, USA
| | - Joseph M Suflita
- Department of Microbiology and Plant Biology, Institute for Energy and the Environment, University of Oklahoma, Norman, OK 73019, USA
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9
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Anaerobic degradation of hexadecane and phenanthrene coupled to sulfate reduction by enriched consortia from northern Gulf of Mexico seafloor sediment. Sci Rep 2019; 9:1239. [PMID: 30718896 PMCID: PMC6361983 DOI: 10.1038/s41598-018-36567-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 11/12/2018] [Indexed: 11/16/2022] Open
Abstract
To advance understanding of the fate of hydrocarbons released from the Deepwater Horizon oil spill and deposited in marine sediments, this study characterized the microbial populations capable of anaerobic hydrocarbon degradation coupled with sulfate reduction in non-seep sediments of the northern Gulf of Mexico. Anaerobic, sediment-free enrichment cultures were obtained with either hexadecane or phenanthrene as sole carbon source and sulfate as a terminal electron acceptor. Phylogenetic analysis revealed that enriched microbial populations differed by hydrocarbon substrate, with abundant SSU rRNA gene amplicon sequences from hexadecane cultures showing high sequence identity (up to 98%) to Desulfatibacillum alkenivorans (family Desulfobacteraceae), while phenanthrene-enriched populations were most closely related to Desulfatiglans spp. (up to 95% sequence identity; family Desulfarculaceae). Assuming complete oxidation to CO2, observed stoichiometric ratios closely resembled the theoretical ratios of 12.25:1 for hexadecane and 8.25:1 for phenanthrene degradation coupled to sulfate reduction. Phenanthrene carboxylic acid was detected in the phenanthrene-degrading enrichment cultures, providing evidence to indicate carboxylation as an activation mechanism for phenanthrene degradation. Metagenome-assembled genomes (MAGs) revealed that phenanthrene degradation is likely mediated by novel genera or families of sulfate-reducing bacteria along with their fermentative syntrophic partners, and candidate genes linked to the degradation of aromatic hydrocarbons were detected for future study.
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10
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Reyes-Sosa MB, Apodaca-Hernández JE, Arena-Ortiz ML. Bioprospecting for microbes with potential hydrocarbon remediation activity on the northwest coast of the Yucatan Peninsula, Mexico, using DNA sequencing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 642:1060-1074. [PMID: 30045488 DOI: 10.1016/j.scitotenv.2018.06.097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 06/05/2018] [Accepted: 06/08/2018] [Indexed: 05/16/2023]
Abstract
Coastal environments harbor diverse microbial communities, which can contain genera with potential bioremediation activity. Next-generation DNA sequencing was used to identify bacteria to the genus level in water and sediment samples collected from the open ocean, shoreline, wetlands and freshwater upwellings on the northwest coast of the Yucatan Peninsula. Supported by an extensive literature review, a phylogenetic investigation of the communities was done using reconstruction of unobserved states software (PICRUSt) to predict metagenome functional content from the sequenced 16S gene in all the samples. Bacterial genera were identified for their potential hydrocarbon bioremediation activity. These included generalist genera commonly reported in hydrocarbon-polluted areas and petroleum reservoirs, as well as specialists such as Alcanivorax and Cycloclasticus. The highest readings for bacteria with potential hydrocarbon bioremediation activity were for the genera Vibrio, Alteromonas, Pseudomonas, Acinetobacter, Burkholderia, Acidovorax and Pseudoalteromonas from different environments in the study area. Some genera were identified only in specific sites; for example, Aquabacterium and Polaromonas were found only in freshwater upwellings. Variation in genera distribution was probably due to differences in environmental conditions in the sampled zones. Bacterial diversity was high in the study area and included numerous genera with known bioremediation activity. Functional prediction of the metagenome indicated that the studied bacterial communities would most probably degrade toluene, naphthalene, chloroalkane and chloroalkene, with lower degradation proportions for aromatic hydrocarbons, fluorobenzoate and xylene. Differences in predicted degradation existed between sediments and water, and between different locations.
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Affiliation(s)
| | | | - María Leticia Arena-Ortiz
- Posgrado en Ciencias del Mar y Limnología UNAM, Mérida, Yucatán, Mexico; Laboratorio de Ecogenonomica Universidad Nacional Autonoma de Mexico.
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11
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Toth CRA, Gieg LM. Time Course-Dependent Methanogenic Crude Oil Biodegradation: Dynamics of Fumarate Addition Metabolites, Biodegradative Genes, and Microbial Community Composition. Front Microbiol 2018; 8:2610. [PMID: 29354103 PMCID: PMC5758579 DOI: 10.3389/fmicb.2017.02610] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/14/2017] [Indexed: 11/13/2022] Open
Abstract
Biodegradation of crude oil in subsurface petroleum reservoirs has adversely impacted most of the world's oil, converting this resource to heavier forms that are of lower quality and more challenging to recover. Oil degradation in deep reservoir environments has been attributed to methanogenesis over geological time, yet our understanding of the processes and organisms mediating oil transformation in the absence of electron acceptors remains incomplete. Here, we sought to identify hydrocarbon activation mechanisms and reservoir-associated microorganisms that may have helped shape the formation of biodegraded oil by incubating oilfield produced water in the presence of light (°API = 32) or heavy crude oil (°API = 16). Over the course of 17 months, we conducted routine analytical (GC, GC-MS) and molecular (PCR/qPCR of assA and bssA genes, 16S rRNA gene sequencing) surveys to assess microbial community composition and activity changes over time. Over the incubation period, we detected the formation of transient hydrocarbon metabolites indicative of alkane and alkylbenzene addition to fumarate, corresponding with increases in methane production and fumarate addition gene abundance. Chemical and gene-based evidence of hydrocarbon biodegradation under methanogenic conditions was supported by the enrichment of hydrocarbon fermenters known to catalyze fumarate addition reactions (e.g., Desulfotomaculum, Smithella), along with syntrophic bacteria (Syntrophus), methanogenic archaea, and several candidate phyla (e.g., “Atribacteria”, “Cloacimonetes”). Our results reveal that fumarate addition is a possible mechanism for catalyzing the methanogenic biodegradation of susceptible saturates and aromatic hydrocarbons in crude oil, and we propose the roles of community members and candidate phyla in our cultures that may be involved in hydrocarbon transformation to methane in crude oil systems.
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Affiliation(s)
- Courtney R A Toth
- Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Lisa M Gieg
- Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
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12
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Qin QS, Feng DS, Liu PF, He Q, Li X, Liu AM, Zhang H, Hu GQ, Cheng L. Metagenomic Characterization of Candidatus Smithella cisternae Strain M82_1, a Syntrophic Alkane-Degrading Bacteria, Enriched from the Shengli Oil Field. Microbes Environ 2017; 32:234-243. [PMID: 28781346 PMCID: PMC5606693 DOI: 10.1264/jsme2.me17022] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The methanogenic degradation of hydrocarbons plays an important role in hydrocarbon-contaminated environments in the absence of an external electron acceptor. Members of Syntrophaceae sublineages were previously reported to be responsible for syntrophic alkane degradation. However, limited information is currently available on their physiological capabilities in nature because it is very challenging to cultivate these as-yet uncultured microbes. We herein performed metagenomic sequencing of the methanogenic hexadecane-degrading culture M82 and recovered a nearly complete genome (2.75 Mb, estimated completeness ≥97%) belonging to Syntrophaceae sublineage II. The assembly genome was tentatively named “Candidatus Smithella cisternae strain M82_1”. Genes encoding alkylsuccinate synthase for alkane activation were identified, suggesting that this organism is capable of oxidizing alkanes through fumarate addition. This capability was further supported by the detection of methyl pentadecyl succinic acid and methyl tetradecyl succinic acid in cultures amended with hexadecane and pentadecane, respectively. Genes encoding enzymes for the β-oxidation of long-chain fatty acids and butyrate were also identified. The electron transfer flavoprotein/DUF224 complex is presumed to link electron flow from acyl-CoA dehydrogenase to a membrane hydrogenase or formate dehydrogenase. Although no indications of Rnf complexes were detected, genes encoding electron-confurcating hydrogenase and formate dehydrogenase were proposed to couple the thermodynamically favorable oxidation of ferredoxin to generate H2 and formate from NADH. Strain M82_1 synthesized ATP from acetyl-CoA by substrate-level phosphorylation or F1F0-ATP synthases. These results provide an insight into the potential metabolic traits and ecophysiological roles of the syntrophic alkane degrader Syntrophaceae.
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Affiliation(s)
- Qian-Shan Qin
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture
| | | | - Peng-Fei Liu
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture
| | - Qiao He
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture
| | - Xia Li
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture
| | | | - Hui Zhang
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture
| | - Guo-Quan Hu
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture
| | - Lei Cheng
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture
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Ghattas AK, Fischer F, Wick A, Ternes TA. Anaerobic biodegradation of (emerging) organic contaminants in the aquatic environment. WATER RESEARCH 2017; 116:268-295. [PMID: 28347952 DOI: 10.1016/j.watres.2017.02.001] [Citation(s) in RCA: 152] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 05/22/2023]
Abstract
Although strictly anaerobic conditions prevail in several environmental compartments, up to now, biodegradation studies with emerging organic contaminants (EOCs), such as pharmaceuticals and personal care products, have mainly focused on aerobic conditions. One of the reasons probably is the assumption that the aerobic degradation is more energetically favorable than degradation under strictly anaerobic conditions. Certain aerobically recalcitrant contaminants, however, are biodegraded under strictly anaerobic conditions and little is known about the organisms and enzymatic processes involved in their degradation. This review provides a comprehensive survey of characteristic anaerobic biotransformation reactions for a variety of well-studied, structurally rather simple contaminants (SMOCs) bearing one or a few different functional groups/structural moieties. Furthermore it summarizes anaerobic degradation studies of more complex contaminants with several functional groups (CMCs), in soil, sediment and wastewater treatment. While strictly anaerobic conditions are able to promote the transformation of several aerobically persistent contaminants, the variety of observed reactions is limited, with reductive dehalogenations and the cleavage of ether bonds being the most prevalent. Thus, it becomes clear that the transferability of degradation mechanisms deduced from culture studies of SMOCs to predict the degradation of CMCs, such as EOCs, in environmental matrices is hampered due the more complex chemical structure bearing different functional groups, different environmental conditions (e.g. matrix, redox, pH), the microbial community (e.g. adaptation, competition) and the low concentrations typical for EOCs.
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Affiliation(s)
- Ann-Kathrin Ghattas
- Federal Institute of Hydrology (BfG), D-56068 Koblenz, Am Mainzer Tor 1, Germany
| | - Ferdinand Fischer
- Federal Institute of Hydrology (BfG), D-56068 Koblenz, Am Mainzer Tor 1, Germany
| | - Arne Wick
- Federal Institute of Hydrology (BfG), D-56068 Koblenz, Am Mainzer Tor 1, Germany
| | - Thomas A Ternes
- Federal Institute of Hydrology (BfG), D-56068 Koblenz, Am Mainzer Tor 1, Germany.
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14
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State of the art of biological processes for coal gasification wastewater treatment. Biotechnol Adv 2016; 34:1064-1072. [DOI: 10.1016/j.biotechadv.2016.06.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 06/19/2016] [Accepted: 06/26/2016] [Indexed: 11/17/2022]
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15
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Wang X, Zhao X, Li H, Jia J, Liu Y, Ejenavi O, Ding A, Sun Y, Zhang D. Separating and characterizing functional alkane degraders from crude-oil-contaminated sites via magnetic nanoparticle-mediated isolation. Res Microbiol 2016; 167:731-744. [PMID: 27475037 DOI: 10.1016/j.resmic.2016.07.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 07/06/2016] [Accepted: 07/08/2016] [Indexed: 11/18/2022]
Abstract
Uncultivable microorganisms account for over 99% of all species on the planet, but their functions are yet not well characterized. Though many cultivable degraders for n-alkanes have been intensively investigated, the roles of functional n-alkane degraders remain hidden in the natural environment. This study introduces the novel magnetic nanoparticle-mediated isolation (MMI) technology in Nigerian soils and successfully separates functional microbes belonging to the families Oxalobacteraceae and Moraxellaceae, which are dominant and responsible for alkane metabolism in situ. The alkR-type n-alkane monooxygenase genes, instead of alkA- or alkP-type, were the key functional genes involved in the n-alkane degradation process. Further physiological investigation via a BIOLOG PM plate revealed some carbon (Tween 20, Tween 40 and Tween 80) and nitrogen (tyramine, l-glutamine and d-aspartic acid) sources promoting microbial respiration and n-alkane degradation. With further addition of promoter carbon or nitrogen sources, the separated functional alkane degraders significantly improved n-alkane biodegradation rates. This suggests that MMI is a promising technology for separating functional microbes from complex microbiota, with deeper insight into their ecological functions and influencing factors. The technique also broadens the application of the BIOLOG PM plate for physiological research on functional yet uncultivable microorganisms.
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Affiliation(s)
- Xinzi Wang
- Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, UK
| | - Xiaohui Zhao
- Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, UK; College of Water Sciences, Beijing Normal University, Beijing 100875, PR China
| | - Hanbing Li
- Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, UK
| | - Jianli Jia
- School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing 100083, PR China
| | - Yueqiao Liu
- Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, UK; College of Water Sciences, Beijing Normal University, Beijing 100875, PR China
| | - Odafe Ejenavi
- Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, UK
| | - Aizhong Ding
- College of Water Sciences, Beijing Normal University, Beijing 100875, PR China
| | - Yujiao Sun
- College of Water Sciences, Beijing Normal University, Beijing 100875, PR China
| | - Dayi Zhang
- Lancaster Environment Center, Lancaster University, Lancaster LA1 4YQ, UK.
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16
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Liang R, Aktas DF, Aydin E, Bonifay V, Sunner J, Suflita JM. Anaerobic Biodegradation of Alternative Fuels and Associated Biocorrosion of Carbon Steel in Marine Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:4844-4853. [PMID: 27058258 DOI: 10.1021/acs.est.5b06388] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Fuels that biodegrade too easily can exacerbate through-wall pitting corrosion of pipelines and tanks and result in unintentional environmental releases. We tested the biological stability of two emerging naval biofuels (camelina-JP5 and Fischer-Tropsch-F76) and their potential to exacerbate carbon steel corrosion in seawater incubations with and without a hydrocarbon-degrading sulfate-reducing bacterium. The inclusion of sediment or the positive control bacterium in the incubations stimulated a similar pattern of sulfate reduction with different inocula. However, the highest rates of sulfate reduction were found in incubations amended with camelina-JP5 [(57.2 ± 2.2)-(80.8 ± 8.1) μM/day] or its blend with petroleum-JP5 (76.7 ± 2.4 μM/day). The detection of a suite of metabolites only in the fuel-amended incubations confirmed that alkylated benzene hydrocarbons were metabolized via known anaerobic mechanisms. Most importantly, general (r(2) = 0.73) and pitting (r(2) = 0.69) corrosion were positively correlated with sulfate loss in the incubations. Thus, the anaerobic biodegradation of labile fuel components coupled with sulfate respiration greatly contributed to the biocorrosion of carbon steel. While all fuels were susceptible to anaerobic metabolism, special attention should be given to camelina-JP5 biofuel due to its relatively rapid biodegradation. We recommend that this biofuel be used with caution and that whenever possible extended storage periods should be avoided.
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Affiliation(s)
- Renxing Liang
- Department of Microbiology and Plant Biology and OU Biocorrosion Center, University of Oklahoma , Norman, Oklahoma 73069, United States
| | - Deniz F Aktas
- Department of Microbiology and Plant Biology and OU Biocorrosion Center, University of Oklahoma , Norman, Oklahoma 73069, United States
| | - Egemen Aydin
- Department of Microbiology and Plant Biology and OU Biocorrosion Center, University of Oklahoma , Norman, Oklahoma 73069, United States
| | - Vincent Bonifay
- Department of Microbiology and Plant Biology and OU Biocorrosion Center, University of Oklahoma , Norman, Oklahoma 73069, United States
| | - Jan Sunner
- Department of Microbiology and Plant Biology and OU Biocorrosion Center, University of Oklahoma , Norman, Oklahoma 73069, United States
| | - Joseph M Suflita
- Department of Microbiology and Plant Biology and OU Biocorrosion Center, University of Oklahoma , Norman, Oklahoma 73069, United States
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17
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Fowler SJ, Toth CRA, Gieg LM. Community Structure in Methanogenic Enrichments Provides Insight into Syntrophic Interactions in Hydrocarbon-Impacted Environments. Front Microbiol 2016; 7:562. [PMID: 27148240 PMCID: PMC4840303 DOI: 10.3389/fmicb.2016.00562] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 04/04/2016] [Indexed: 11/17/2022] Open
Abstract
The methanogenic biodegradation of crude oil involves the conversion of hydrocarbons to methanogenic substrates by syntrophic bacteria and subsequent methane production by methanogens. Assessing the metabolic roles played by various microbial species in syntrophic communities remains a challenge, but such information has important implications for bioremediation and microbial enhanced energy recovery technologies. Many factors such as changing environmental conditions or substrate variations can influence the composition and biodegradation capabilities of syntrophic microbial communities in hydrocarbon-impacted environments. In this study, a methanogenic crude oil-degrading enrichment culture was successively transferred onto the single long chain fatty acids palmitate or stearate followed by their parent alkanes, hexadecane or octadecane, respectively, in order to assess the impact of different substrates on microbial community composition and retention of hydrocarbon biodegradation genes. 16S rRNA gene sequencing showed that a reduction in substrate diversity resulted in a corresponding loss of microbial diversity, but that hydrocarbon biodegradation genes (such as assA/masD encoding alkylsuccinate synthase) could be retained within a community even in the absence of hydrocarbon substrates. Despite substrate-related diversity changes, all communities were dominated by hydrogenotrophic and acetotrophic methanogens along with bacteria including Clostridium sp., members of the Deltaproteobacteria, and a number of other phyla. Microbial co-occurrence network analysis revealed a dense network of interactions amongst syntrophic bacteria and methanogens that were maintained despite changes in the substrates for methanogenesis. Our results reveal the effect of substrate diversity loss on microbial community diversity, indicate that many syntrophic interactions are stable over time despite changes in substrate pressure, and show that syntrophic interactions amongst bacteria themselves are as important as interactions between bacteria and methanogens in complex methanogenic communities.
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Affiliation(s)
- S Jane Fowler
- Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary AB, Canada
| | - Courtney R A Toth
- Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary AB, Canada
| | - Lisa M Gieg
- Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary AB, Canada
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18
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Herath A, Wawrik B, Qin Y, Zhou J, Callaghan AV. Transcriptional response of Desulfatibacillum alkenivorans AK-01 to growth on alkanes: insights from RT-qPCR and microarray analyses. FEMS Microbiol Ecol 2016; 92:fiw062. [PMID: 27009900 DOI: 10.1093/femsec/fiw062] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2016] [Indexed: 12/16/2022] Open
Abstract
Microbial transformation of n-alkanes in anaerobic ecosystems plays a pivotal role in biogeochemical carbon cycling and bioremediation, but the requisite genetic machinery is not well elucidated.Desulfatibacillum alkenivorans AK-01 utilizes n-alkanes (C13 to C18) and contains two genomic loci encoding alkylsuccinate synthase (ASS) gene clusters. ASS catalyzes alkane addition to fumarate to form methylalkylsuccinic acids. We hypothesized that the genes in the two clusters would be differentially expressed depending on the alkane substrate utilized for growth. RT-qPCR was used to investigate ass-gene expression across AK-01's known substrate range, and microarray-based transcriptomic analysis served to investigate whole-cell responses to growth on n-hexadecane versus hexadecanoate. RT-qPCR revealed induction of ass gene cluster 1 during growth on all tested alkane substrates, and the transcriptional start sites in cluster 1 were determined via 5'RACE. Induction of ass gene cluster 2 was not observed under the tested conditions. Transcriptomic analysis indicated that the upregulation of genes potentially involved in methylalkylsuccinate metabolism, including methylmalonyl-CoA mutase and a putative carboxyl transferase. These findings provide new directions for studying the transcriptional regulation of genes involved in alkane addition to fumarate, fumarate recycling and the processing of methylalkylsuccinates with regard to isolates, enrichment cultures and ecological datasets.
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Affiliation(s)
- Anjumala Herath
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Boris Wawrik
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
| | - Yujia Qin
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA Institute of Environmental Genomics, Stephenson Research Center, 101 David L. Boren Blvd, Norman, OK 73019, USA
| | - Jizhong Zhou
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA Institute of Environmental Genomics, Stephenson Research Center, 101 David L. Boren Blvd, Norman, OK 73019, USA Earth Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94270, USA State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Amy V Callaghan
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019, USA
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19
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Jiménez N, Richnow HH, Vogt C, Treude T, Krüger M. Methanogenic Hydrocarbon Degradation: Evidence from Field and Laboratory Studies. J Mol Microbiol Biotechnol 2016; 26:227-42. [PMID: 26959375 DOI: 10.1159/000441679] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Microbial transformation of hydrocarbons to methane is an environmentally relevant process taking place in a wide variety of electron acceptor-depleted habitats, from oil reservoirs and coal deposits to contaminated groundwater and deep sediments. Methanogenic hydrocarbon degradation is considered to be a major process in reservoir degradation and one of the main processes responsible for the formation of heavy oil deposits and oil sands. In the absence of external electron acceptors such as oxygen, nitrate, sulfate or Fe(III), fermentation and methanogenesis become the dominant microbial metabolisms. The major end product under these conditions is methane, and the only electron acceptor necessary to sustain the intermediate steps in this process is CO2, which is itself a net product of the overall reaction. We are summarizing the state of the art and recent advances in methanogenic hydrocarbon degradation research. Both the key microbial groups involved as well as metabolic pathways are described, and we discuss the novel insights into methanogenic hydrocarbon-degrading populations studied in laboratory as well as environmental systems enabled by novel cultivation-based and molecular approaches. Their possible implications on energy resources, bioremediation of contaminated sites, deep-biosphere research, and consequences for atmospheric composition and ultimately climate change are also addressed.
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Affiliation(s)
- Núria Jiménez
- Department of Resource Geochemistry, BGR - Federal Institute for Geosciences and Natural Resources, Hannover, Germany
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20
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Wilkes H, Buckel W, Golding BT, Rabus R. Metabolism of Hydrocarbons in n-Alkane-Utilizing Anaerobic Bacteria. J Mol Microbiol Biotechnol 2016; 26:138-51. [PMID: 26959725 DOI: 10.1159/000442160] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The glycyl radical enzyme-catalyzed addition of n-alkanes to fumarate creates a C-C-bond between two concomitantly formed stereogenic carbon centers. The configurations of the two diastereoisomers of the product resulting from n-hexane activation by the n-alkane-utilizing denitrifying bacterium strain HxN1, i.e. (1-methylpentyl)succinate, were assigned as (2S,1'R) and (2R,1'R). Experiments with stereospecifically deuterated n-(2,5-2H2)hexanes revealed that exclusively the pro-S hydrogen atom is abstracted from C2 of the n-alkane by the enzyme and later transferred back to C3 of the alkylsuccinate formed. These results indicate that the alkylsuccinate-forming reaction proceeds with an inversion of configuration at the carbon atom (C2) of the n-alkane forming the new C-C-bond, and thus stereochemically resembles a SN2-type reaction. Therefore, the reaction may occur in a concerted manner, which may avoid the highly energetic hex-2-yl radical as an intermediate. The reaction is associated with a significant primary kinetic isotope effect (kH/kD ≥3) for hydrogen, indicating that the homolytic C-H-bond cleavage is involved in the first irreversible step of the reaction mechanism. The (1-methylalkyl)succinate synthases of n-alkane-utilizing anaerobic bacteria apparently have very broad substrate ranges enabling them to activate not only aliphatic but also alkyl-aromatic hydrocarbons. Thus, two denitrifiers and one sulfate reducer were shown to convert the nongrowth substrate toluene to benzylsuccinate and further to the dead-end product benzoyl-CoA. For this purpose, however, the modified β-oxidation pathway known from alkylbenzene-utilizing bacteria was not employed, but rather the pathway used for n-alkane degradation involving CoA ligation, carbon skeleton rearrangement and decarboxylation. Furthermore, various n-alkane- and alkylbenzene-utilizing denitrifiers and sulfate reducers were found to be capable of forming benzyl alcohols from diverse alkylbenzenes, putatively via dehydrogenases. The thermophilic sulfate reducer strain TD3 forms n-alkylsuccinates during growth with n-alkanes or crude oil, which, based on the observed patterns of homologs, do not derive from a terminal activation of n-alkanes.
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Affiliation(s)
- Heinz Wilkes
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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21
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Zhou J, Bian XY, Zhou L, Mbadinga SM, Yang SZ, Liu JF, Gu JD, Mu BZ. Synthesis and characterization of anaerobic degradation biomarkers of n-alkanes via hydroxylation/carboxylation pathways. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2016; 22:31-37. [PMID: 26863073 DOI: 10.1255/ejms.1402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Metabolite profiling is a powerful method in research on anaerobic biodegradation of hydrocarbons. Hydroxylation and carboxylation are proposed pathways in anaerobic degradation but very little direct evidence is available about metabolites and signature biomarkers. 2-Acetylalkanoic acid is a potential signature metabolite because of its unique and specific structure among possible intermediates. A procedure for the synthesis of four homologues with various carbon chain lengths was proposed and the characteristics of 2-acetyl- alkanoic acid esters were investigated using four derivatization processes, namely methyl, ethyl, n-butyl and trimethylsilyl esterification. Four intermediate fragments observed were at m/z 73 + 14n, 87 + 14n, 102 + 14n (n = 1, 2 and 4 for methyl, ethyl and n-butyl ester, respectively) and [M - 42]+ for three of the derivatization methods. For silylation, characteristic ions were observed at m/z 73, 117, [M - 42](+) and [M - 55](+). These are basic and significant data for the future identification of potential intermediates of the hydroxylation and carboxylation pathways in hydrocarbon degradation.
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Affiliation(s)
- Jing Zhou
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, PR China.
| | - Xin-Yu Bian
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, PR China.
| | - Lei Zhou
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, PR China.
| | - Serge Maurice Mbadinga
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, PR China and Shanghai Collaborative Innovation Center for Biomanufacturing Technology, Shanghai 200237, PR China.
| | - Shi-Zhong Yang
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, PR China.
| | - Jin-Feng Liu
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, PR China.
| | - Ji-Dong Gu
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, PR China.
| | - Bo-Zhong Mu
- State Key Laboratory of Bioreactor Engineering and Institute of Applied Chemistry, East China University of Science and Technology, Shanghai 200237, PR China and Shanghai Collaborative Innovation Center for Biomanufacturing Technology, Shanghai 200237, PR China.
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22
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Bharadwaj VS, Vyas S, Villano SM, Maupin CM, Dean AM. Unravelling the impact of hydrocarbon structure on the fumarate addition mechanism--a gas-phase ab initio study. Phys Chem Chem Phys 2016; 17:4054-66. [PMID: 25566585 DOI: 10.1039/c4cp04317k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The fumarate addition reaction mechanism is central to the anaerobic biodegradation pathway of various hydrocarbons, both aromatic (e.g., toluene, ethyl benzene) and aliphatic (e.g., n-hexane, dodecane). Succinate synthase enzymes, which belong to the glycyl radical enzyme family, are the main facilitators of these biochemical reactions. The overall catalytic mechanism that converts hydrocarbons to a succinate molecule involves three steps: (1) initial H-abstraction from the hydrocarbon by the radical enzyme, (2) addition of the resulting hydrocarbon radical to fumarate, and (3) hydrogen abstraction by the addition product to regenerate the radical enzyme. Since the biodegradation of hydrocarbon fuels via the fumarate addition mechanism is linked to bio-corrosion, an improved understanding of this reaction is imperative to our efforts of predicting the susceptibility of proposed alternative fuels to biodegradation. An improved understanding of the fuel biodegradation process also has the potential to benefit bioremediation. In this study, we consider model aromatic (toluene) and aliphatic (butane) compounds to evaluate the impact of hydrocarbon structure on the energetics and kinetics of the fumarate addition mechanism by means of high level ab initio gas-phase calculations. We predict that the rate of toluene degradation is ∼100 times faster than butane at 298 K, and that the first abstraction step is kinetically significant for both hydrocarbons, which is consistent with deuterium isotope effect studies on toluene degradation. The detailed computations also show that the predicted stereo-chemical preference of the succinate products for both toluene and butane are due to the differences in the radical addition rate constants for the various isomers. The computational and kinetic modeling work presented here demonstrates the importance of considering pre-reaction and product complexes in order to accurately treat gas phase systems that involve intra and inter-molecular non-covalent interactions.
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Affiliation(s)
- Vivek S Bharadwaj
- Chemical and Biological Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401, USA.
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23
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Gittel A, Donhauser J, Røy H, Girguis PR, Jørgensen BB, Kjeldsen KU. Ubiquitous Presence and Novel Diversity of Anaerobic Alkane Degraders in Cold Marine Sediments. Front Microbiol 2015; 6:1414. [PMID: 26733961 PMCID: PMC4681840 DOI: 10.3389/fmicb.2015.01414] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 11/27/2015] [Indexed: 01/05/2023] Open
Abstract
Alkanes are major constituents of crude oil and are released to the marine environment by natural seepage and from anthropogenic sources. Due to their chemical inertness, their removal from anoxic marine sediments is primarily controlled by the activity of anaerobic alkane-degrading microorganisms. To facilitate comprehensive cultivation-independent surveys of the diversity and distribution of anaerobic alkane degraders, we designed novel PCR primers that cover all known diversity of the 1-methylalkyl succinate synthase gene (masD/assA), which catalyzes the initial activation of alkanes. We studied masD/assA gene diversity in pristine and seepage-impacted Danish coastal sediments, as well as in sediments and alkane-degrading enrichment cultures from the Middle Valley (MV) hydrothermal vent system in the Pacific Northwest. MasD/assA genes were ubiquitously present, and the primers captured the diversity of both known and previously undiscovered masD/assA gene diversity. Seepage sediments were dominated by a single masD/assA gene cluster, which is presumably indicative of a substrate-adapted community, while pristine sediments harbored a diverse range of masD/assA phylotypes including those present in seepage sediments. This rare biosphere of anaerobic alkane degraders will likely increase in abundance in the event of seepage or accidental oil spillage. Nanomolar concentrations of short-chain alkanes (SCA) were detected in pristine and seepage sediments. Interestingly, anaerobic alkane degraders closely related to strain BuS5, the only SCA degrader in pure culture, were found in mesophilic MV enrichments, but not in cold sediments from Danish waters. We propose that the new masD/assA gene lineages in these sediments represent novel phylotypes that are either fueled by naturally occurring low levels of SCA or that metabolize medium- to long-chain alkanes. Our study highlights that masD/assA genes are a relevant diagnostic marker to identify seepage and microseepage, e.g., during prospecting for oil and gas, and may act as an indicator of anthropogenic oil spills in marine sediments.
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Affiliation(s)
- Antje Gittel
- Center for Geomicrobiology, Department of Bioscience, Aarhus University Aarhus, Denmark
| | - Johanna Donhauser
- Center for Geomicrobiology, Department of Bioscience, Aarhus University Aarhus, Denmark
| | - Hans Røy
- Center for Geomicrobiology, Department of Bioscience, Aarhus University Aarhus, Denmark
| | - Peter R Girguis
- Department of Organismic and Evolutionary Biology, Harvard University Cambridge, MA, USA
| | - Bo B Jørgensen
- Center for Geomicrobiology, Department of Bioscience, Aarhus University Aarhus, Denmark
| | - Kasper U Kjeldsen
- Center for Geomicrobiology, Department of Bioscience, Aarhus University Aarhus, Denmark
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Stauffert M, Cravo-Laureau C, Duran R. Dynamic of sulphate-reducing microorganisms in petroleum-contaminated marine sediments inhabited by the polychaete Hediste diversicolor. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:15273-15284. [PMID: 25256587 DOI: 10.1007/s11356-014-3624-y] [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: 07/16/2014] [Accepted: 09/16/2014] [Indexed: 06/03/2023]
Abstract
The behaviour of sulphate-reducing microbial community was investigated at the oxic-anoxic interface (0-2 cm) of marine sediments when submitted to oil and enhanced bioturbation activities by the addition of Hediste diversicolor. Although total hydrocarbon removal was not improved by the addition of H. diversicolor, terminal restriction fragment length polymorphism (T-RFLP) analyses based on dsrAB (dissimilatory sulphite reductase) genes and transcripts showed different patterns according to the presence of H. diversicolor which favoured the abundance of dsrB genes during the early stages of incubation. Complementary DNA (cDNA) dsrAB libraries revealed that in presence of H. diversicolor, most dsrAB sequences belonged to hydrocarbonoclastic Desulfobacteraceae, suggesting that sulphate-reducing microorganisms (SRMs) may play an active role in hydrocarbon biodegradation in sediments where the reworking activity is enhanced. Furthermore, the presence of dsrAB sequences related to sequences found associated to environments with high dinitrogen fixation activity suggested potential N2 fixation by SRMs in bioturbated-polluted sediments.
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Affiliation(s)
- Magalie Stauffert
- Equipe Environnement et Microbiologie, Université de Pau et des Pays de l'Adour, IPREM UMR CNRS 5254, BP 1155, 64013, Pau Cedex, France
| | - Cristiana Cravo-Laureau
- Equipe Environnement et Microbiologie, Université de Pau et des Pays de l'Adour, IPREM UMR CNRS 5254, BP 1155, 64013, Pau Cedex, France.
| | - Robert Duran
- Equipe Environnement et Microbiologie, Université de Pau et des Pays de l'Adour, IPREM UMR CNRS 5254, BP 1155, 64013, Pau Cedex, France
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Lv L, Mbadinga SM, Wang LY, Liu JF, Gu JD, Mu BZ, Yang SZ. Acetoclastic methanogenesis is likely the dominant biochemical pathway of palmitate degradation in the presence of sulfate. Appl Microbiol Biotechnol 2015; 99:7757-69. [DOI: 10.1007/s00253-015-6669-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 04/29/2015] [Accepted: 05/01/2015] [Indexed: 10/23/2022]
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Insights into the Anaerobic Biodegradation Pathway of n-Alkanes in Oil Reservoirs by Detection of Signature Metabolites. Sci Rep 2015; 5:9801. [PMID: 25966798 PMCID: PMC4429370 DOI: 10.1038/srep09801] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 03/16/2015] [Indexed: 11/28/2022] Open
Abstract
Anaerobic degradation of alkanes in hydrocarbon-rich environments has been documented
and different degradation strategies proposed, of which the most encountered one is
fumarate addition mechanism, generating alkylsuccinates as specific biomarkers.
However, little is known about the mechanisms of anaerobic degradation of alkanes in
oil reservoirs, due to low concentrations of signature metabolites and lack of mass
spectral characteristics to allow identification. In this work, we used a
multidisciplinary approach combining metabolite profiling and selective gene assays
to establish the biodegradation mechanism of alkanes in oil reservoirs. A total of
twelve production fluids from three different oil reservoirs were collected and
treated with alkali; organic acids were extracted, derivatized with ethanol to form
ethyl esters and determined using GC-MS analysis. Collectively, signature metabolite
alkylsuccinates of parent compounds from C1 to C8 together with their (putative)
downstream metabolites were detected from these samples. Additionally, metabolites
indicative of the anaerobic degradation of mono- and poly-aromatic hydrocarbons
(2-benzylsuccinate, naphthoate, 5,6,7,8-tetrahydro-naphthoate) were also observed.
The detection of alkylsuccinates and genes encoding for alkylsuccinate synthase
shows that anaerobic degradation of alkanes via fumarate addition occurs in oil
reservoirs. This work provides strong evidence on the in situ anaerobic
biodegradation mechanisms of hydrocarbons by fumarate addition.
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A Comprehensive Review of Aliphatic Hydrocarbon Biodegradation by Bacteria. Appl Biochem Biotechnol 2015; 176:670-99. [PMID: 25935219 DOI: 10.1007/s12010-015-1603-5] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 03/31/2015] [Indexed: 02/07/2023]
Abstract
Hydrocarbons are relatively recalcitrant compounds and are classified as high-priority pollutants. However, these compounds are slowly degraded by a large variety of microorganisms. Bacteria are able to degrade aliphatic saturated and unsaturated hydrocarbons via both aerobic and anaerobic pathways. Branched hydrocarbons and cyclic hydrocarbons are also degraded by bacteria. The aerobic bacteria use different types of oxygenases, including monooxygenase, cytochrome-dependent oxygenase and dioxygenase, to insert one or two atoms of oxygen into their targets. Anaerobic bacteria, on the other hand, employ a variety of simple organic and inorganic molecules, including sulphate, nitrate, carbonate and metals, for hydrocarbon oxidation.
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Mono- and dialkyl glycerol ether lipids in anaerobic bacteria: biosynthetic insights from the mesophilic sulfate reducer Desulfatibacillum alkenivorans PF2803T. Appl Environ Microbiol 2015; 81:3157-68. [PMID: 25724965 DOI: 10.1128/aem.03794-14] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/22/2015] [Indexed: 11/20/2022] Open
Abstract
Bacterial glycerol ether lipids (alkylglycerols) have received increasing attention during the last decades, notably due to their potential role in cell resistance or adaptation to adverse environmental conditions. Major uncertainties remain, however, regarding the origin, biosynthesis, and modes of formation of these uncommon bacterial lipids. We report here the preponderance of monoalkyl- and dialkylglycerols (1-O-alkyl-, 2-O-alkyl-, and 1,2-O-dialkylglycerols) among the hydrolyzed lipids of the marine mesophilic sulfate-reducing proteobacterium Desulfatibacillum alkenivorans PF2803T grown on n-alkenes (pentadec-1-ene or hexadec-1-ene) as the sole carbon and energy source. Alkylglycerols account for one-third to two-thirds of the total cellular lipids (alkylglycerols plus acylglycerols), depending on the growth substrate, with dialkylglycerols contributing to one-fifth to two-fifths of the total ether lipids. The carbon chain distribution of the lipids of D. alkenivorans also depends on that of the substrate, but the chain length and methyl-branching patterns of fatty acids and monoalkyl- and dialkylglycerols are systematically congruent, supporting the idea of a biosynthetic link between the three classes of compounds. Vinyl ethers (1-alken-1'-yl-glycerols, known as plasmalogens) are not detected among the lipids of strain PF2803T. Cultures grown on different (per)deuterated n-alkene, n-alkanol, and n-fatty acid substrates further demonstrate that saturated alkylglycerols are not formed via the reduction of hypothetic alken-1'-yl intermediates. Our results support an unprecedented biosynthetic pathway to monoalkyl/monoacyl- and dialkylglycerols in anaerobic bacteria and suggest that n-alkyl compounds present in the environment can serve as the substrates for supplying the building blocks of ether phospholipids of heterotrophic bacteria.
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Khelifi N, Amin Ali O, Roche P, Grossi V, Brochier-Armanet C, Valette O, Ollivier B, Dolla A, Hirschler-Réa A. Anaerobic oxidation of long-chain n-alkanes by the hyperthermophilic sulfate-reducing archaeon, Archaeoglobus fulgidus. THE ISME JOURNAL 2014; 8:2153-66. [PMID: 24763368 PMCID: PMC4992073 DOI: 10.1038/ismej.2014.58] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 03/11/2014] [Accepted: 03/16/2014] [Indexed: 11/08/2022]
Abstract
The thermophilic sulfate-reducing archaeon Archaeoglobus fulgidus strain VC-16 (DSM 4304), which is known to oxidize fatty acids and n-alkenes, was shown to oxidize saturated hydrocarbons (n-alkanes in the range C10-C21) with thiosulfate or sulfate as a terminal electron acceptor. The amount of n-hexadecane degradation observed was in stoichiometric agreement with the theoretically expected amount of thiosulfate reduction. One of the pathways used by anaerobic microorganisms to activate alkanes is addition to fumarate that involves alkylsuccinate synthase as a key enzyme. A search for genes encoding homologous enzymes in A. fulgidus identified the pflD gene (locus-tag AF1449) that was previously annotated as a pyruvate formate lyase. A phylogenetic analysis revealed that this gene is of bacterial origin and was likely acquired by A. fulgidus from a bacterial donor through a horizontal gene transfer. Based on three-dimensional modeling of the corresponding protein and molecular dynamic simulations, we hypothesize an alkylsuccinate synthase activity for this gene product. The pflD gene expression was upregulated during the growth of A. fulgidus on an n-alkane (C16) compared with growth on a fatty acid. Our results suggest that anaerobic alkane degradation in A. fulgidus may involve the gene pflD in alkane activation through addition to fumarate. These findings highlight the possible importance of hydrocarbon oxidation at high temperatures by A. fulgidus in hydrothermal vents and the deep biosphere.
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Affiliation(s)
- Nadia Khelifi
- Aix Marseille Université, CNRS, Université de Toulon, IRD, MIO UM 110, Marseille, France
| | - Oulfat Amin Ali
- Aix Marseille Université, CNRS, Université de Toulon, IRD, MIO UM 110, Marseille, France
| | - Philippe Roche
- Centre de Recherche en Cancérologie de Marseille (CRCM), CNRS UMR 7258, INSERM U 1068, Institut Paoli-Calmettes, Aix Marseille Université, Marseille, France
| | - Vincent Grossi
- Université de Lyon, Université Lyon 1, CNRS, UMR 5276, Laboratoire de Géologie de Lyon, Villeurbanne, France
| | - Céline Brochier-Armanet
- Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France
| | - Odile Valette
- Aix Marseille Université, CNRS, LCB UMR 7283, Marseille, France
| | - Bernard Ollivier
- Aix Marseille Université, CNRS, Université de Toulon, IRD, MIO UM 110, Marseille, France
| | - Alain Dolla
- Aix Marseille Université, CNRS, LCB UMR 7283, Marseille, France
| | - Agnès Hirschler-Réa
- Aix Marseille Université, CNRS, Université de Toulon, IRD, MIO UM 110, Marseille, France
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Stauffert M, Cravo-Laureau C, Duran R. Structure of hydrocarbonoclastic nitrate-reducing bacterial communities in bioturbated coastal marine sediments. FEMS Microbiol Ecol 2014; 89:580-93. [DOI: 10.1111/1574-6941.12359] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 05/13/2014] [Accepted: 05/19/2014] [Indexed: 11/28/2022] Open
Affiliation(s)
- Magalie Stauffert
- Equipe Environnement et Microbiologie; IPREM UMR CNRS 5254; Université de Pau et des Pays de l'Adour; Pau Cedex France
| | - Cristiana Cravo-Laureau
- Equipe Environnement et Microbiologie; IPREM UMR CNRS 5254; Université de Pau et des Pays de l'Adour; Pau Cedex France
| | - Robert Duran
- Equipe Environnement et Microbiologie; IPREM UMR CNRS 5254; Université de Pau et des Pays de l'Adour; Pau Cedex France
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Agrawal A, Gieg LM. In situ detection of anaerobic alkane metabolites in subsurface environments. Front Microbiol 2013; 4:140. [PMID: 23761789 PMCID: PMC3671572 DOI: 10.3389/fmicb.2013.00140] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 05/17/2013] [Indexed: 11/13/2022] Open
Abstract
Alkanes comprise a substantial fraction of crude oil and refined fuels. As such, they are prevalent within deep subsurface fossil fuel deposits and in shallow subsurface environments such as aquifers that are contaminated with hydrocarbons. These environments are typically anaerobic, and host diverse microbial communities that can potentially use alkanes as substrates. Anaerobic alkane biodegradation has been reported to occur under nitrate-reducing, sulfate-reducing, and methanogenic conditions. Elucidating the pathways of anaerobic alkane metabolism has been of interest in order to understand how microbes can be used to remediate contaminated sites. Alkane activation primarily occurs by addition to fumarate, yielding alkylsuccinates, unique anaerobic metabolites that can be used to indicate in situ anaerobic alkane metabolism. These metabolites have been detected in hydrocarbon-contaminated shallow aquifers, offering strong evidence for intrinsic anaerobic bioremediation. Recently, studies have also revealed that alkylsuccinates are present in oil and coal seam production waters, indicating that anaerobic microbial communities can utilize alkanes in these deeper subsurface environments. In many crude oil reservoirs, the in situ anaerobic metabolism of hydrocarbons such as alkanes may be contributing to modern-day detrimental effects such as oilfield souring, or may lead to more beneficial technologies such as enhanced energy recovery from mature oilfields. In this review, we briefly describe the key metabolic pathways for anaerobic alkane (including n-alkanes, isoalkanes, and cyclic alkanes) metabolism and highlight several field reports wherein alkylsuccinates have provided evidence for anaerobic in situ alkane metabolism in shallow and deep subsurface environments.
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Affiliation(s)
- Akhil Agrawal
- Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary Calgary, AB, Canada
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Tan B, Dong X, Sensen CW, Foght J. Metagenomic analysis of an anaerobic alkane-degrading microbial culture: potential hydrocarbon-activating pathways and inferred roles of community members. Genome 2013; 56:599-611. [PMID: 24237341 DOI: 10.1139/gen-2013-0069] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A microbial community (short-chain alkane-degrading culture, SCADC) enriched from an oil sands tailings pond was shown to degrade C6-C10 alkanes under methanogenic conditions. Total genomic DNA from SCADC was subjected to 454 pyrosequencing, Illumina paired-end sequencing, and 16S rRNA amplicon pyrotag sequencing; the latter revealed 320 operational taxonomic units at 5% distance. Metagenomic sequences were subjected to in-house quality control and co-assembly, yielding 984 086 contigs, and annotation using MG-Rast and IMG. Substantial nucleotide and protein recruitment to Methanosaeta concilii, Syntrophus aciditrophicus, and Desulfobulbus propionicus reference genomes suggested the presence of closely related strains in SCADC; other genomes were not well mapped, reflecting the paucity of suitable reference sequences for such communities. Nonetheless, we detected numerous homologues of putative hydrocarbon succinate synthase genes (e.g., assA, bssA, and nmsA) implicated in anaerobic hydrocarbon degradation, suggesting the ability of the SCADC microbial community to initiate methanogenic alkane degradation by addition to fumarate. Annotation of a large contig revealed analogues of the ass operon 1 in the alkane-degrading sulphate-reducing bacterium Desulfatibacillum alkenivorans AK-01. Despite being enriched under methanogenic-fermentative conditions, additional metabolic functions inferred by COG profiling indicated multiple CO(2) fixation pathways, organic acid utilization, hydrogenase activity, and sulphate reduction.
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Affiliation(s)
- Boonfei Tan
- a Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
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Callaghan AV. Enzymes involved in the anaerobic oxidation of n-alkanes: from methane to long-chain paraffins. Front Microbiol 2013; 4:89. [PMID: 23717304 PMCID: PMC3653055 DOI: 10.3389/fmicb.2013.00089] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 03/31/2013] [Indexed: 11/13/2022] Open
Abstract
Anaerobic microorganisms play key roles in the biogeochemical cycling of methane and non-methane alkanes. To date, there appear to be at least three proposed mechanisms of anaerobic methane oxidation (AOM). The first pathway is mediated by consortia of archaeal anaerobic methane oxidizers and sulfate-reducing bacteria (SRB) via “reverse methanogenesis” and is catalyzed by a homolog of methyl-coenzyme M reductase. The second pathway is also mediated by anaerobic methane oxidizers and SRB, wherein the archaeal members catalyze both methane oxidation and sulfate reduction and zero-valent sulfur is a key intermediate. The third AOM mechanism is a nitrite-dependent, “intra-aerobic” pathway described for the denitrifying bacterium, ‘Candidatus Methylomirabilis oxyfera.’ It is hypothesized that AOM proceeds via reduction of nitrite to nitric oxide, followed by the conversion of two nitric oxide molecules to dinitrogen and molecular oxygen. The latter can be used to functionalize the methane via a particulate methane monooxygenase. With respect to non-methane alkanes, there also appear to be novel mechanisms of activation. The most well-described pathway is the addition of non-methane alkanes across the double bond of fumarate to form alkyl-substituted succinates via the putative glycyl radical enzyme, alkylsuccinate synthase (also known as methylalkylsuccinate synthase). Other proposed mechanisms include anaerobic hydroxylation via ethylbenzene dehydrogenase-like enzymes and an “intra-aerobic” denitrification pathway similar to that described for ‘Methylomirabilis oxyfera.’
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Affiliation(s)
- Amy V Callaghan
- Department of Microbiology and Plant Biology, University of Oklahoma Norman, OK, USA
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Ji Y, Mao G, Wang Y, Bartlam M. Structural insights into diversity and n-alkane biodegradation mechanisms of alkane hydroxylases. Front Microbiol 2013; 4:58. [PMID: 23519435 PMCID: PMC3604635 DOI: 10.3389/fmicb.2013.00058] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 02/28/2013] [Indexed: 11/13/2022] Open
Abstract
Environmental microbes utilize four degradation pathways for the oxidation of n-alkanes. Although the enzymes degrading n-alkanes in different microbes may vary, enzymes functioning in the first step in the aerobic degradation of alkanes all belong to the alkane hydroxylases. Alkane hydroxylases are a class of enzymes that insert oxygen atoms derived from molecular oxygen into different sites of the alkane terminus (or termini) depending on the type of enzymes. In this review, we summarize the different types of alkane hydroxylases, their degrading steps, and compare typical enzymes from various classes with regard to their three-dimensional structures, in order to provide insights into how the enzymes mediate their different roles in the degradation of n-alkanes and what determines their different substrate ranges. Through the above analyzes, the degrading mechanisms of enzymes can be elucidated and molecular biological methods can be utilized to expand their catalytic roles in the petrochemical industry or in bioremediation of oil-contaminated environments.
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Affiliation(s)
- Yurui Ji
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai UniversityTianjin, China
- State Key Laboratory of Medicinal Chemical Biology, Nankai UniversityTianjin, China
| | - Guannan Mao
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai UniversityTianjin, China
| | - Yingying Wang
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai UniversityTianjin, China
| | - Mark Bartlam
- State Key Laboratory of Medicinal Chemical Biology, Nankai UniversityTianjin, China
- College of Life Sciences, Nankai UniversityTianjin, China
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Hasinger M, Scherr KE, Lundaa T, Bräuer L, Zach C, Loibner AP. Changes in iso- and n-alkane distribution during biodegradation of crude oil under nitrate and sulphate reducing conditions. J Biotechnol 2011; 157:490-8. [PMID: 22001845 DOI: 10.1016/j.jbiotec.2011.09.027] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 09/22/2011] [Accepted: 09/26/2011] [Indexed: 11/26/2022]
Abstract
Crude oil consists of a large number of hydrocarbons with different susceptibility to microbial degradation. The influence of hydrocarbon structure and molecular weight on hydrocarbon biodegradation under anaerobic conditions is not fully explored. In this study oxygen, nitrate and sulphate served as terminal electron acceptors (TEAs) for the microbial degradation of a paraffin-rich crude oil in a freshly contaminated soil. During 185 days of incubation, alkanes from n-C11 to n-C39, three n- to iso-alkane ratios commonly used as weathering indicators and the unresolved complex mixture (UCM) were quantified and statistically analyzed. The use of different TEAs for hydrocarbon degradation resulted in dissimilar degradative patterns for n- and iso-alkanes. While n-alkane biodegradation followed well-established patterns under aerobic conditions, lower molecular weight alkanes were found to be more recalcitrant than mid- to high-molecular weight alkanes under nitrate-reducing conditions. Biodegradation with sulphate as the TEA was most pronounced for long-chain (n-C32 to n-C39) alkanes. The observation of increasing ratios of n-C17 to pristane and of n-C18 to phytane provides first evidence of the preferential degradation of branched over normal alkanes under sulphate reducing conditions. The formation of distinctly different n- and iso-alkane biodegradation fingerprints under different electron accepting conditions may be used to assess the occurrence of specific degradation processes at a contaminated site. The use of n- to iso-alkane ratios for this purpose may require adjustment if applied for anaerobic sites.
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Affiliation(s)
- Marion Hasinger
- Department for Agrobiotechnology, Institute for Environmental Biotechnology, University of Natural Resources and Life Sciences Vienna, Konrad Lorenz Strasse 20, 3430 Tulln, Austria
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Rabus R, Jarling R, Lahme S, Kühner S, Heider J, Widdel F, Wilkes H. Co-metabolic conversion of toluene in anaerobic n-alkane-degrading bacteria. Environ Microbiol 2011; 13:2576-86. [PMID: 21880102 DOI: 10.1111/j.1462-2920.2011.02529.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Diverse microorganisms have been described to degrade petroleum hydrocarbons anaerobically. Strains able to utilize n-alkanes do not grow with aromatic hydrocarbons, whereas strains able to utilize aromatic hydrocarbons do not grow with n-alkanes. To investigate this specificity in more detail, three anaerobic n-alkane degraders (two denitrifying, one sulfate-reducing) and eight anaerobic alkylbenzene degraders (five denitrifying, three sulfate-reducing) were incubated with mixtures of n-alkanes and toluene. Whereas the toluene degradationers formed only the characteristic toluene-derived benzylsuccinate and benzoate, but no n-alkane-derived metabolites, the n-alkane degraders formed toluene-derived benzylsuccinate, 4-phenylbutanoate, phenylacetate and benzoate besides the regular n-alkane-derived (1-methylalkyl)succinates and methyl-branched alkanoates. The co-metabolic conversion of toluene by anaerobic n-alkane degraders to the level of benzoate obviously follows the anaerobic n-alkane degradation pathway with C-skeleton rearrangement and decarboxylation rather than the β-oxidation pathway of anaerobic toluene metabolism. Hence, petroleum-derived aromatic metabolites detectable in anoxic environments may not be exclusively formed by genuine alkylbenzene degraders. In addition, the hitherto largely unexplored fate of fumarate hydrogen during the activation reactions was examined with (2,3-(2) H(2) )fumarate as co-substrate. Deuterium was completely exchanged with hydrogen at the substituted carbon atom (C-2) of the succinate adducts of n-alkanes, whereas it is retained in toluene-derived benzylsuccinate, regardless of the type of enzyme catalysing the fumarate addition reaction.
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Affiliation(s)
- Ralf Rabus
- Universität Oldenburg, Carl-von-Ossietzky Straße 9-11, 26111 Oldenburg, Germany.
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Siegert M, Cichocka D, Herrmann S, Gründger F, Feisthauer S, Richnow HH, Springael D, Krüger M. Accelerated methanogenesis from aliphatic and aromatic hydrocarbons under iron- and sulfate-reducing conditions. FEMS Microbiol Lett 2010; 315:6-16. [DOI: 10.1111/j.1574-6968.2010.02165.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Savage KN, Krumholz LR, Gieg LM, Parisi VA, Suflita JM, Allen J, Philp RP, Elshahed MS. Biodegradation of low-molecular-weight alkanes under mesophilic, sulfate-reducing conditions: metabolic intermediates and community patterns. FEMS Microbiol Ecol 2010; 72:485-95. [DOI: 10.1111/j.1574-6941.2010.00866.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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40
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Anaerobic oxidation of fatty acids and alkenes by the hyperthermophilic sulfate-reducing archaeon Archaeoglobus fulgidus. Appl Environ Microbiol 2010; 76:3057-60. [PMID: 20305028 DOI: 10.1128/aem.02810-09] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Archaeoglobus fulgidus oxidizes fatty acids (C(4) to C(18)) and n-alk-1-enes (C(12:1) to C(21:1)) in the presence of thiosulfate as a terminal electron acceptor. End products of metabolism were CO(2) and sulfide. Growth on perdeuterated hexadecene yielded C(15)- to C(17)-labeled fatty acids as metabolites, thus confirming the ability of A. fulgidus to oxidize alkyl chains.
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Jin S, Fallgren P, Luo H. Feasibility of enhanced biodegradation of petroleum compounds in groundwater under denitrifying conditions. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2010; 84:357-361. [PMID: 20111949 DOI: 10.1007/s00128-010-9935-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2009] [Accepted: 01/13/2010] [Indexed: 05/28/2023]
Abstract
Groundwater was collected from a petroleum hydrocarbon contaminated site and characterized for microbial and physiochemical properties to assess the feasibility of enhanced natural attenuation. Results demonstrate the depletion of nitrate and dominance of denitrifying bacteria in the groundwater. Microcosm studies of amending nitrate and nutrients were attempted to enhanced biodegradation of petroleum compounds under denitrifying condition. Results show that 75% of petroleum compounds was degraded within 152-day in microcosms amended with nitrate, compared to 25% removal in the non-amended controls. Data indicate that nitrate amendment to groundwater may offer a viable remedy for enhanced natural attenuation of petroleum compounds.
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Affiliation(s)
- Song Jin
- School of Resources and Environment, Hefei University of Technology, Hefei, People's Republic of China.
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Lara-Martín PA, Gómez-Parra A, Sanz JL, González-Mazo E. Anaerobic degradation pathway of linear Alkylbenzene sulfonates (LAS) in sulfate-reducing marine sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:1670-6. [PMID: 20121087 DOI: 10.1021/es9032887] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Linear alkylbenzene sulfonates (LAS) are among the principal synthetic surfactants used worldwide. Their presence in the environment has been reported in a significant number of studies, and it has been generally assumed that LAS are not biotransformed in the absence of oxygen. However, laboratory experiments performed by our group using anoxic marine sediments have reported LAS degradation percentages that can reach up to 79% in 165 days. Here, we show for the first time the initial reaction metabolites (generated via fumarate addition to the LAS molecules), their biotransformation into sulfophenyl carboxylic acids (SPC), and the progressive degradation of these by successive beta-oxidation reactions. Advanced mass spectrometry has been used to carry out the identification of these compounds. This is the first time that an anaerobic degradation pathway for LAS is described, and these results represent a significant advance in understanding the final fate of these and other similar compounds in anoxic environments.
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Affiliation(s)
- Pablo A Lara-Martín
- Departamento de Quimica Fisica, Universidad de Cadiz, Campus Rio San Pedro s/n, 11510 Puerto Real, Cadiz, Spain.
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Anaerobic biodegradation of n-hexadecane by a nitrate-reducing consortium. Appl Environ Microbiol 2008; 75:1339-44. [PMID: 19114507 DOI: 10.1128/aem.02491-08] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nitrate-reducing enrichments, amended with n-hexadecane, were established with petroleum-contaminated sediment from Onondaga Lake. Cultures were serially diluted to yield a sediment-free consortium. Clone libraries and denaturing gradient gel electrophoresis analysis of 16S rRNA gene community PCR products indicated the presence of uncultured alpha- and betaproteobacteria similar to those detected in contaminated, denitrifying environments. Cultures were incubated with H(34)-hexadecane, fully deuterated hexadecane (d(34)-hexadecane), or H(34)-hexadecane and NaH(13)CO(3). Gas chromatography-mass spectrometry analysis of silylated metabolites resulted in the identification of [H(29)]pentadecanoic acid, [H(25)]tridecanoic acid, [1-(13)C]pentadecanoic acid, [3-(13)C]heptadecanoic acid, [3-(13)C]10-methylheptadecanoic acid, and d(27)-pentadecanoic, d(25)-, and d(2)(4)-tridecanoic acids. The identification of these metabolites suggests a carbon addition at the C-3 position of hexadecane, with subsequent beta-oxidation and transformation reactions (chain elongation and C-10 methylation) that predominantly produce fatty acids with odd numbers of carbons. Mineralization of [1-(14)C]hexadecane was demonstrated based on the recovery of (14)CO(2) in active cultures.
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Abstract
Methane has long been known to be used as a carbon and energy source by some aerobic alpha- and delta-proteobacteria. In these organisms the metabolism of methane starts with its oxidation with O(2) to methanol, a reaction catalyzed by a monooxygenase and therefore restricted to the aerobic world. Methane has recently been shown to also fuel the growth of anaerobic microorganisms. The oxidation of methane with sulfate and with nitrate have been reported, but the mechanisms of anaerobic methane oxidation still remains elusive. Sulfate-dependent methane oxidation is catalyzed by methanotrophic archaea, which are related to the Methanosarcinales and which grow in close association with sulfate-reducing delta-proteobacteria. There is evidence that anaerobic methane oxidation with sulfate proceeds at least in part via reversed methanogenesis involving the nickel enzyme methyl-coenzyme M reductase for methane activation, which under standard conditions is an endergonic reaction, and thus inherently slow. Methane oxidation coupled to denitrification is mediated by bacteria belonging to a novel phylum and does not involve methyl-coenzyme M reductase. The first step in methane oxidation is most likely the exergonic formation of 2-methylsuccinate from fumarate and methane catalyzed by a glycine-radical enzyme.
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Affiliation(s)
- Rudolf K Thauer
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany.
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45
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Anaerobic alkane-degrading strain AK-01 contains two alkylsuccinate synthase genes. Biochem Biophys Res Commun 2007; 366:142-8. [PMID: 18053803 DOI: 10.1016/j.bbrc.2007.11.094] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Accepted: 11/19/2007] [Indexed: 11/24/2022]
Abstract
The sulfate-reducing strain AK-01 activates alkanes via addition of the subterminal carbon to the double bond of fumarate. This reaction is similar to the action of the glycyl radical enzyme benzylsuccinate synthase (Bss). It was hypothesized that strain AK-01 possesses a similar enzyme. Degenerate bssA primers and inverse PCR were used to amplify two unlinked genes (assA1 and assA2), which encode catalytic subunits of glycyl radical type enzymes. Subsequent genome sequencing of AK-01 revealed two ass operons. SDS-PAGE analysis of AK-01 grown on n-hexadecane revealed a 95-kDa protein which is absent in hexadecanoate-grown cells. LC-MS/MS data obtained from a tryptic digest of this protein match the deduced amino acid sequence encoded by assA1, thus confirming AssA1's involvement in alkane metabolism. This report is the first description of a gene involved in anaerobic n-alkane metabolism in a sulfate-reducer and provides evidence for a novel glycyl radical enzyme.
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Miralles G, Nérini D, Manté C, Acquaviva M, Doumenq P, Michotey V, Nazaret S, Bertrand JC, Cuny P. Effects of spilled oil on bacterial communities of mediterranean coastal anoxic sediments chronically subjected to oil hydrocarbon contamination. MICROBIAL ECOLOGY 2007; 54:646-61. [PMID: 17334965 DOI: 10.1007/s00248-007-9221-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 01/15/2007] [Accepted: 01/22/2007] [Indexed: 05/14/2023]
Abstract
The effects of spilled oil on sedimentary bacterial communities were examined in situ at 20 m water depth in a Mediterranean coastal area. Sediment collected at an experimental site chronically subjected to hydrocarbon inputs was reworked into PVC cores with or without a massive addition of crude Arabian light oil ( approximately 20 g kg(-1) dry weight). Cores were reinserted into the sediment and incubated in situ at the sampling site (20 m water depth) for 135 and 503 days. The massive oil contamination induced significant shifts in the structure of the indigenous bacterial communities as shown by ribosomal intergenic spacer analysis (RISA). The vertical heterogeneity of the bacterial communities within the sediment was more pronounced in the oiled sediments particularly after 503 days of incubation. Response to oil of the deeper depth communities (8-10 cm) was slower than that of superficial depth communities (0-1 and 2-4 cm). Analysis of the oil composition by gas chromatography revealed a typical microbial alteration of n-alkanes during the experiment. Predominant RISA bands in oiled sediments were affiliated to hydrocarbonoclastic bacteria sequences. In particular, a 395-bp RISA band, which was the dominant band in all the oiled sediments for both incubation times, was closely related to hydrocarbonoclastic sulfate-reducing bacteria (SRB). These bacteria may have contributed to the main fingerprint changes and to the observed biodegradation of n-alkanes. This study provides useful information on bacterial dynamics in anoxic contaminated infralittoral sediments and highlights the need to assess more precisely the contribution of SRB to bioremediation in oil anoxic contaminated areas.
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Affiliation(s)
- Gilles Miralles
- Laboratoire de Microbiologie, de Géochimie et d'Ecologie Marines, CNRS-UMR 6117, Centre d'Océanologie de Marseille, Cedex 9, Case 901, Campus de Luminy, Marseille, 13288, France
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47
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Anaerobic 1-alkene metabolism by the alkane- and alkene-degrading sulfate reducer Desulfatibacillum aliphaticivorans strain CV2803T. Appl Environ Microbiol 2007; 73:7882-90. [PMID: 17965214 DOI: 10.1128/aem.01097-07] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The alkane- and alkene-degrading, marine sulfate-reducing bacterium Desulfatibacillum aliphaticivorans strain CV2803(T), known to oxidize n-alkanes anaerobically by fumarate addition at C-2, was investigated for its 1-alkene metabolism. The total cellular fatty acids of this strain were predominantly C-(even number) (C-even) when it was grown on C-even 1-alkenes and predominantly C-(odd number) (C-odd) when it was grown on C-odd 1-alkenes. Detailed analyses of those fatty acids by gas chromatography-mass spectrometry after 6- to 10-week incubations allowed the identification of saturated 2- and 4-ethyl-, 2- and 4-methyl-, and monounsaturated 4-methyl-branched fatty acids with chain lengths that correlated with those of the 1-alkene. The growth of D. aliphaticivorans on (per)deuterated 1-alkenes provided direct evidence of the anaerobic transformation of these alkenes into the corresponding 1-alcohols and into linear as well as 10- and 4-methyl-branched fatty acids. Experiments performed with [(13)C]bicarbonate indicated that the initial activation of 1-alkene by the addition of inorganic carbon does not occur. These results demonstrate that D. aliphaticivorans metabolizes 1-alkene by the oxidation of the double bond at C-1 and by the subterminal addition of organic carbon at both ends of the molecule [C-2 and C-(omega-1)]. The detection of ethyl-branched fatty acids from unlabeled 1-alkenes further suggests that carbon addition also occurs at C-3. Alkylsuccinates were not observed as potential initial intermediates in alkene metabolism. Based on our observations, the first pathways for anaerobic 1-alkene metabolism in an anaerobic bacterium are proposed. Those pathways indicate that diverse initial reactions of 1-alkene activation can occur simultaneously in the same strain of sulfate-reducing bacterium.
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Wentzel A, Ellingsen TE, Kotlar HK, Zotchev SB, Throne-Holst M. Bacterial metabolism of long-chain n-alkanes. Appl Microbiol Biotechnol 2007; 76:1209-21. [PMID: 17673997 DOI: 10.1007/s00253-007-1119-1] [Citation(s) in RCA: 207] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2007] [Revised: 07/10/2007] [Accepted: 07/11/2007] [Indexed: 10/23/2022]
Abstract
Degradation of alkanes is a widespread phenomenon in nature, and numerous microorganisms, both prokaryotic and eukaryotic, capable of utilizing these substrates as a carbon and energy source have been isolated and characterized. In this review, we summarize recent advances in the understanding of bacterial metabolism of long-chain n-alkanes. Bacterial strategies for accessing these highly hydrophobic substrates are presented, along with systems for their enzymatic degradation and conversion into products of potential industrial value. We further summarize the current knowledge on the regulation of bacterial long-chain n-alkane metabolism and survey progress in understanding bacterial pathways for utilization of n-alkanes under anaerobic conditions.
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Affiliation(s)
- Alexander Wentzel
- Department of Biotechnology, Norwegian University of Science and Technology, Sem Saelandsvei 6/8, 7491 Trondheim, Norway.
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49
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Miralles G, Grossi V, Acquaviva M, Duran R, Claude Bertrand J, Cuny P. Alkane biodegradation and dynamics of phylogenetic subgroups of sulfate-reducing bacteria in an anoxic coastal marine sediment artificially contaminated with oil. CHEMOSPHERE 2007; 68:1327-34. [PMID: 17337033 DOI: 10.1016/j.chemosphere.2007.01.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 01/16/2007] [Accepted: 01/17/2007] [Indexed: 05/14/2023]
Abstract
For 503 days, unoiled control and artificially oiled sediments were incubated in situ at 20m water depth in a Mediterranean coastal area. Degradation of the aliphatic fraction of the oil added was followed by GC-MS. At the same time, terminal restriction fragment length polymorphism (T-RFLP) of 16S rRNA encoding genes was used to detect dynamics in the sulfate-reducing bacteria (SRB) community in response to the oil contamination. Specific polymerase chain reaction (PCR) primer sets for five generic or suprageneric groups of SRB were used for PCR amplification of DNA extracted from sediments. During the experiment, hydrocarbons from C(17) to C(30) were significantly degraded even in strictly anoxic sediment layers. Of the five SRB groups, only two groups were detected in the sediments (control and oiled), namely the Desulfococcus-Desulfonema-Desulfosarcina-like group and the Desulfovibrio-Desulfomicrobium-like group. Statistical analysis of community patterns revealed dynamic changes over time within these two groups following the contamination. Significant differences in community patterns were recorded in artificially oiled compared with control sediments. Cloning and sequencing of 16S rRNA encoding genes performed after 503 days showed that many of the most abundant sequences were closely related to hydrocarbonoclastic SRB which could have played an active role in the observed biodegradation of aliphatic hydrocarbons. Results from the present study provide useful information on the dynamics of dominant SRB in heavily oil-contaminated sediments and their potential for anaerobic biodegradation for the treatment of spilled oil in anoxic marine environments.
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Affiliation(s)
- Gilles Miralles
- Laboratoire de Microbiologie, de Géochimie et d'Ecologie Marines, CNRS-UMR 6117, Centre d'Océanologie de Marseille, Campus de Luminy, Case 901, 13288 Marseille Cedex 9, France
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50
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Winderl C, Schaefer S, Lueders T. Detection of anaerobic toluene and hydrocarbon degraders in contaminated aquifers using benzylsuccinate synthase (bssA) genes as a functional marker. Environ Microbiol 2007; 9:1035-46. [PMID: 17359274 DOI: 10.1111/j.1462-2920.2006.01230.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Benzylsuccinate synthase (Bss) is the key enzyme of anaerobic toluene degradation and has been found in all anaerobic toluene degrading bacterial isolates tested. However, only a few pure cultures capable of anaerobic toluene oxidation are available to date, and it is important to understand the relevance of these model organisms for in situ bioremediation of hydrocarbon-contaminated aquifers. Due to their phylogenetic dispersal, it is not possible to specifically target anaerobic toluene degraders using marker rRNA genes. We therefore established an assay targeting a approximately 794 bp fragment within the Bss alpha-subunit (bssA) gene, which allows for the specific detection and affiliation of both known and unknown anaerobic degraders. Three distinct tar-oil-contaminated aquifer sites were screened for intrinsic bssA gene pools in order to identify and compare the diversity of hydrocarbon degraders present at these selected sites. We were able to show that local diversity patterns of degraders were entirely distinct, apparently highly specialized and well-adapted to local biogeochemical settings. Discovered at one of the sites were bssA genes closely related to that of Geobacter spp., which provides evidence for an importance of iron reduction for toluene degradation in these sediments. Retrieved from the other two sites, dominated by sulfate reduction, were previously unidentified bssA genes and also deeply branching putative bssA homologues. We provide evidence for a previously unrecognized diversity of anaerobic toluene degraders and also of other hydrocarbon degraders using fumarate-adding key reactions in contaminated aquifers. These findings enhance our current understanding of intrinsic hydrocarbon-degrading microbial communities in perturbed aquifers and may have potential for the future assessment and prediction of natural attenuation based on degradation genes.
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Affiliation(s)
- Christian Winderl
- Institute of Groundwater Ecology, GSF - National Research Center for Environment and Health, Neuherberg, Germany
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