1
|
Chen M, Grégoire DS, Bain JG, Blowes DW, Hug LA. Legacy copper/nickel mine tailings potentially harbor novel iron/sulfur cycling microorganisms within highly variable communities. Appl Environ Microbiol 2024:e0014324. [PMID: 38814057 DOI: 10.1128/aem.00143-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 05/07/2024] [Indexed: 05/31/2024] Open
Abstract
The oxidation of sulfide-bearing mine tailings catalyzed by acidophilic iron and sulfur-oxidizing bacteria releases toxic metals and other contaminants into soil and groundwater as acid mine drainage. Understanding the environmental variables that control the community structure and metabolic activity of microbes indigenous to tailings (especially the abiotic stressors of low pH and high dissolved metal content) is crucial to developing sustainable bioremediation strategies. We determined the microbial community composition along two continuous vertical gradients of Cu/Ni mine tailings at each of two tailings impoundments near Sudbury, Ontario. 16S rRNA amplicon data showed high variability in community diversity and composition between locations, as well as at different depths within each location. A temporal comparison for one tailings location showed low fluctuation in microbial communities across 2 years. Differences in community composition correlated most strongly with pore-water pH, Eh, alkalinity, salinity, and the concentration of several dissolved metals (including iron, but not copper or nickel). The relative abundances of individual genera differed in their degrees of correlation with geochemical factors. Several abundant lineages present at these locations have not previously been associated with mine tailings environments, including novel species predicted to be involved in iron and sulfur cycling.IMPORTANCEMine tailings represent a significant threat to North American freshwater, with legacy tailings areas generating acid mine drainage (AMD) that contaminates rivers, lakes, and aquifers. Microbial activity accelerates AMD formation through oxidative metabolic processes but may also ameliorate acidic tailings by promoting secondary mineral precipitation and immobilizing dissolved metals. Tailings exhibit high geochemical variation within and between mine sites and may harbor many novel extremophiles adapted to high concentrations of toxic metals. Characterizing the unique microbiomes associated with tailing environments is key to identifying consortia that may be used as the foundation for innovative mine-waste bioremediation strategies. We provide an in-depth analysis of microbial diversity at four copper/nickel mine tailings impoundments, describe how communities (and individual lineages) differ based on geochemical gradients, predict organisms involved in AMD transformations, and identify taxonomically novel groups present that have not previously been observed in mine tailings.
Collapse
Affiliation(s)
- Molly Chen
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Daniel S Grégoire
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
- Department of Chemistry, Carleton University, Ottawa, Ontario, Canada
| | - Jeffrey G Bain
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - David W Blowes
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Laura A Hug
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| |
Collapse
|
2
|
Diep P, Stogios PJ, Evdokimova E, Savchenko A, Mahadevan R, Yakunin AF. Ni(II)-binding affinity of CcNikZ-II and its homologs: the role of the HH-prong and variable loop revealed by structural and mutational studies. FEBS J 2024. [PMID: 38555564 DOI: 10.1111/febs.17125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/30/2024] [Accepted: 03/13/2024] [Indexed: 04/02/2024]
Abstract
Extracytoplasmic Ni(II)-binding proteins (NiBPs) are molecular shuttles involved in cellular nickel uptake. Here, we determined the crystal structure of apo CcNikZ-II at 2.38 Å, which revealed a Ni(II)-binding site comprised of the double His (HH-)prong (His511, His512) and a short variable (v-)loop nearby (Thr59-Thr64, TEDKYT). Mutagenesis of the site identified Glu60 and His511 as critical for high affinity Ni(II)-binding. Phylogenetic analysis showed 15 protein clusters with two groups containing the HH-prong. Metal-binding assays with 11 purified NiBPs containing this feature yielded higher Ni(II)-binding affinities. Replacement of the wild type v-loop with those from other NiBPs improved the affinity by up to an order of magnitude. This work provides molecular insights into the determinants for Ni(II) affinity and paves way for NiBP engineering.
Collapse
Affiliation(s)
- Patrick Diep
- Department of Chemical Engineering and Applied Chemistry, BioZone - Centre for Applied Bioscience and Bioengineering, University of Toronto, Toronto, Ontario, Canada
- Systems & Synthetic Biology Group, Biosciences and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Peter J Stogios
- Department of Chemical Engineering and Applied Chemistry, BioZone - Centre for Applied Bioscience and Bioengineering, University of Toronto, Toronto, Ontario, Canada
| | - Elena Evdokimova
- Department of Chemical Engineering and Applied Chemistry, BioZone - Centre for Applied Bioscience and Bioengineering, University of Toronto, Toronto, Ontario, Canada
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, BioZone - Centre for Applied Bioscience and Bioengineering, University of Toronto, Toronto, Ontario, Canada
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Radhakrishnan Mahadevan
- Department of Chemical Engineering and Applied Chemistry, BioZone - Centre for Applied Bioscience and Bioengineering, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Alexander F Yakunin
- Department of Chemical Engineering and Applied Chemistry, BioZone - Centre for Applied Bioscience and Bioengineering, University of Toronto, Toronto, Ontario, Canada
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Bangor, Wales, UK
| |
Collapse
|
3
|
Zhang Y, O'Loughlin EJ, Park SY, Kwon MJ. Effects of Fe(III) (hydr)oxide mineralogy on the development of microbial communities originating from soil, surface water, groundwater, and aerosols. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:166993. [PMID: 37717756 DOI: 10.1016/j.scitotenv.2023.166993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/09/2023] [Accepted: 09/09/2023] [Indexed: 09/19/2023]
Abstract
Microbial Fe(III) reduction is a key component of the iron cycle in natural environments. However, the susceptibility of Fe(III) (hydr)oxides to microbial reduction varies depending on the mineral's crystallinity, and the type of Fe(III) (hydr)oxide in turn will affect the composition of the microbial community. We created microcosm reactors with microbial communities from four different sources (soil, surface water, groundwater, and aerosols), three Fe(III) (hydr)oxides (lepidocrocite, goethite, and hematite) as electron acceptors, and acetate as an electron donor to investigate the shaping effect of Fe(III) mineral type on the development of microbial communities. During a 10-month incubation, changes in microbial community composition, Fe(III) reduction, and acetate utilization were monitored. Overall, there was greater reduction of lepidocrocite than of goethite and hematite, and the development of microbial communities originating from the same source diverged when supplied with different Fe(III) (hydr)oxides. Furthermore, each Fe(III) mineral was associated with unique taxa that emerged from different sources. This study illustrates the taxonomic diversity of Fe(III)-reducing microbes from a broad range of natural environments.
Collapse
Affiliation(s)
- Yidan Zhang
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea
| | - Edward J O'Loughlin
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States
| | - Su-Young Park
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea
| | - Man Jae Kwon
- Department of Earth and Environmental Sciences, Korea University, Seoul 02841, South Korea.
| |
Collapse
|
4
|
Akaçin İ, Ersoy Ş, Doluca O, Güngörmüşler M. Using custom-built primers and nanopore sequencing to evaluate CO-utilizer bacterial and archaeal populations linked to bioH 2 production. Sci Rep 2023; 13:17025. [PMID: 37813931 PMCID: PMC10562470 DOI: 10.1038/s41598-023-44357-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 10/06/2023] [Indexed: 10/11/2023] Open
Abstract
The microbial community composition of five distinct thermophilic hot springs was effectively described in this work, using broad-coverage nanopore sequencing (ONT MinION sequencer). By examining environmental samples from the same source, but from locations with different temperatures, bioinformatic analysis revealed dramatic changes in microbial diversity and archaeal abundance. More specifically, no archaeal presence was reported with universal bacterial primers, whereas a significant archaea presence and also a wider variety of bacterial species were reported. These results revealed the significance of primer preference for microbiomes in extreme environments. Bioinformatic analysis was performed by aligning the reads to 16S microbial databases for identification using three different alignment methods, Epi2Me (Fastq 16S workflow), Kraken, and an in-house BLAST tool, including comparison at the genus and species levels. As a result, this approach to data analysis had a significant impact on the genera identified, and thus, it is recommended that use of multiple analysis tools to support findings on taxonomic identification using the 16S region until more precise bioinformatics tools become available. This study presents the first compilation of the ONT-based inventory of the hydrogen producers in the designated hot springs in Türkiye.
Collapse
Affiliation(s)
- İlayda Akaçin
- Division of Bioengineering, Graduate School, Izmir University of Economics, Sakarya Caddesi No: 156, 35330, Balçova, Izmir, Türkiye
| | - Şeymanur Ersoy
- Division of Bioengineering, Graduate School, Izmir University of Economics, Sakarya Caddesi No: 156, 35330, Balçova, Izmir, Türkiye
| | - Osman Doluca
- Division of Bioengineering, Graduate School, Izmir University of Economics, Sakarya Caddesi No: 156, 35330, Balçova, Izmir, Türkiye
- Department of Biomedical Engineering, Faculty of Engineering, Izmir University of Economics, Sakarya Caddesi No: 156, 35330, Balçova, Izmir, Türkiye
| | - Mine Güngörmüşler
- Division of Bioengineering, Graduate School, Izmir University of Economics, Sakarya Caddesi No: 156, 35330, Balçova, Izmir, Türkiye.
- Department of Genetics and Bioengineering, Faculty of Engineering, Izmir University of Economics, Sakarya Caddesi No: 156, 35330, Balçova, Izmir, Türkiye.
| |
Collapse
|
5
|
Roberts M, Srivastava P, Webster G, Weightman AJ, Sapsford DJ. Biostimulation of jarosite and iron oxide-bearing mine waste enhances subsequent metal recovery. JOURNAL OF HAZARDOUS MATERIALS 2023; 445:130498. [PMID: 36459883 DOI: 10.1016/j.jhazmat.2022.130498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 06/17/2023]
Abstract
Novel resource recovery technologies are required for metals-bearing hazardous wastes in order to achieve circular economy outcomes and industrial symbiosis. Iron oxide and co-occurring hydroxysulphate-bearing wastes are globally abundant and often contain other elements of value. This work addresses the biostimulation of indigenous microbial communities within an iron oxide/ hydroxysulphate-bearing waste and its effect on the subsequent recoverability of metals by hydrochloric, sulphuric, citric acids, and EDTA. Laboratory-scale flow-through column reactors were used to examine the effect of using glycerol (10% w/w) to stimulate the in situ microbial community in an iron oxide/ hydroxysulphate-bearing mine waste. The effects on the evolution of leachate chemistry, changes in microbiological community, and subsequent hydrometallurgical extractability of metals were studied. Results demonstrated increased leachability and selectivity of Pb, Cu, and Zn relative to iron after biostimulation with a total of 0.027 kg of glycerol per kg of waste. Biostimulation, which can be readily applied in situ, potentially opens new routes to metal recovery from globally abundant waste streams that contain jarosite and iron oxides.
Collapse
Affiliation(s)
- Mark Roberts
- School of Engineering, Cardiff University, Queen's Building, The Parade, Cardiff CF24 3AA, United Kingdom
| | - Pallavee Srivastava
- School of Engineering, Cardiff University, Queen's Building, The Parade, Cardiff CF24 3AA, United Kingdom.
| | - Gordon Webster
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, United Kingdom
| | - Andrew J Weightman
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, United Kingdom
| | - Devin J Sapsford
- School of Engineering, Cardiff University, Queen's Building, The Parade, Cardiff CF24 3AA, United Kingdom
| |
Collapse
|
6
|
Shao P, Chen Y, Gu D, Zeng J, Zhang S, Wu Y, Lin X. Resistance and resilience of soil bacterial community to zero-valent iron disposal of lindane contamination. CHEMOSPHERE 2022; 306:135612. [PMID: 35817188 DOI: 10.1016/j.chemosphere.2022.135612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 04/29/2022] [Accepted: 07/03/2022] [Indexed: 06/15/2023]
Abstract
Zero-valent iron (ZVI, Fe0) enables chemical reduction of environmental pollutants coupled with reactivity loss due to surface oxidation. During ZVI treatment process, however, microbial community stability in terms of resistance and resilience remains largely unclear. Here, we monitored bacterial community succession over a 4 weeks period in soil microcosms with or without 2% (w/w) Fe0 amendment. To simulate soil pollution, 100 μg g-1 chlorinated pesticide lindane (γ-hexachlorocyclohexane) was added to the microcosms as a model contaminant. In addition to microbial activity as measured by soil organic carbon mineralization, bacterial abundance, diversity and composition were determined using qPCR and high-throughput sequencing of 16 S rRNA genes. Co-occurrence analysis was performed to reveal the interaction patterns within the bacterial communities. The results indicated that ZVI caused near-complete transformation of lindane, while in the microcosms without Fe0 amendment the pesticide was recalcitrant. ZVI strongly inhibited CO2-efflux at the early stage of incubation, but the bacterial community appeared to be less sensitive to Fe0 amendment. The ratios of negative to positive correlations between network nodes suggested that Fe0 had marginal influence on community stability compared to the lindane treatments, which destabilized the bacterial community. Community succession occurred in the presence of ZVI, as exemplified by a dominancy transition from anaerobic to aerobic taxa. Yet, ZVI alleviated the stress of lindane on soil bacteria by improving community structure and increasing network complexity. Taken together, these findings demonstrate the stability of soil bacterial community under Fe0 stress, which might be conducive to functional recovery of soil microorganisms following ZVI remediation.
Collapse
Affiliation(s)
- Pengfei Shao
- College of Life Sciences, Henan Agricultural University, Zhengzhou, 450046, China; Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing, 210008, China.
| | - Yuzhu Chen
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing, 210008, China
| | - Decheng Gu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing, 210008, China
| | - Jun Zeng
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing, 210008, China
| | - Shimin Zhang
- College of Life Sciences, Henan Agricultural University, Zhengzhou, 450046, China.
| | - Yucheng Wu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing, 210008, China.
| | - Xiangui Lin
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing, 210008, China
| |
Collapse
|
7
|
Edel M, Philipp LA, Lapp J, Reiner J, Gescher J. Electron transfer of extremophiles in bioelectrochemical systems. Extremophiles 2022; 26:31. [PMID: 36222927 PMCID: PMC9556394 DOI: 10.1007/s00792-022-01279-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 10/02/2022] [Indexed: 11/30/2022]
Abstract
The interaction of bacteria and archaea with electrodes is a relatively new research field which spans from fundamental to applied research and influences interdisciplinary research in the fields of microbiology, biochemistry, biotechnology as well as process engineering. Although a substantial understanding of electron transfer processes between microbes and anodes and between microbes and cathodes has been achieved in mesophilic organisms, the mechanisms used by microbes under extremophilic conditions are still in the early stages of discovery. Here, we review our current knowledge on the biochemical solutions that evolved for the interaction of extremophilic organisms with electrodes. To this end, the available knowledge on pure cultures of extremophilic microorganisms has been compiled and the study has been extended with the help of bioinformatic analyses on the potential distribution of different electron transfer mechanisms in extremophilic microorganisms.
Collapse
Affiliation(s)
- Miriam Edel
- Institute of Technical Microbiology, Hamburg University of Technology, Hamburg, Germany
| | - Laura-Alina Philipp
- Institute of Technical Microbiology, Hamburg University of Technology, Hamburg, Germany
| | - Jonas Lapp
- Institute of Technical Microbiology, Hamburg University of Technology, Hamburg, Germany
| | - Johannes Reiner
- Karlsruhe Institute of Technology, Engler-Bunte-Institute, Karlsruhe, Germany
| | - Johannes Gescher
- Institute of Technical Microbiology, Hamburg University of Technology, Hamburg, Germany.
| |
Collapse
|
8
|
Nixon SL, Bonsall E, Cockell CS. Limitations of microbial iron reduction under extreme conditions. FEMS Microbiol Rev 2022; 46:6645348. [PMID: 35849069 PMCID: PMC9629499 DOI: 10.1093/femsre/fuac033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 06/23/2022] [Accepted: 07/15/2022] [Indexed: 01/09/2023] Open
Abstract
Microbial iron reduction is a widespread and ancient metabolism on Earth, and may plausibly support microbial life on Mars and beyond. Yet, the extreme limits of this metabolism are yet to be defined. To investigate this, we surveyed the recorded limits to microbial iron reduction in a wide range of characterized iron-reducing microorganisms (n = 141), with a focus on pH and temperature. We then calculated Gibbs free energy of common microbially mediated iron reduction reactions across the pH-temperature habitability space to identify thermodynamic limits. Comparing predicted and observed limits, we show that microbial iron reduction is generally reported at extremes of pH or temperature alone, but not when these extremes are combined (with the exception of a small number of acidophilic hyperthermophiles). These patterns leave thermodynamically favourable combinations of pH and temperature apparently unoccupied. The empty spaces could be explained by experimental bias, but they could also be explained by energetic and biochemical limits to iron reduction at combined extremes. Our data allow for a review of our current understanding of the limits to microbial iron reduction at extremes and provide a basis to test more general hypotheses about the extent to which biochemistry establishes the limits to life.
Collapse
Affiliation(s)
- Sophie L Nixon
- Corresponding author: Department of Earth and Environmental Sciences, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK. E-mail:
| | - Emily Bonsall
- Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, United Kingdom
| | - Charles S Cockell
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3FD, United Kingdom
| |
Collapse
|
9
|
Kochetkova TV, Podosokorskaya OA, Elcheninov AG, Kublanov IV. Diversity of Thermophilic Prokaryotes Inhabiting Russian Natural Hot Springs. Microbiology (Reading) 2022. [DOI: 10.1134/s0026261722010064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
10
|
Mao Z, Gräßle F, Frey J, Franchini P, Schleheck D, Müller N, Schink B. Phosphitispora fastidiosa gen. nov. sp. nov., a new dissimilatory phosphite-oxidizing anaerobic bacterium isolated from anaerobic sewage sludge. Int J Syst Evol Microbiol 2021; 71. [PMID: 34878375 DOI: 10.1099/ijsem.0.005142] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A new strictly anaerobic bacterium, strain DYL19T, was enriched and isolated with phosphite as the sole electron donor and CO2 as a single carbon source and electron acceptor from anaerobic sewage sludge sampled at a sewage treatment plant in Constance, Germany. It is a Gram-positive, spore-forming, slightly curved, rod-shaped bacterium which oxidizes phosphite to phosphate while reducing CO2 to biomass and small amounts of acetate. Optimal growth is observed at 30 °C, pH 7.2, with a doubling time of 3 days. Beyond phosphite, no further inorganic or organic electron donor can be used, and no other electron acceptor than CO2 is reduced. Sulphate inhibits growth with phosphite and CO2. The G+C content is 45.95 mol%, and dimethylmenaquinone-7 is the only quinone detectable in the cells. On the basis of 16S rRNA gene sequence analysis and other chemotaxonomic properties, strain DYL19T is described as the type strain of a new genus and species, Phosphitispora fastidiosa gen. nov., sp. nov.
Collapse
Affiliation(s)
- Zhuqing Mao
- Department of Biology, University of Konstanz, Constance, Germany.,Konstanz Research School Chemical Biology, University of Konstanz, Constance, Germany
| | - Fabian Gräßle
- Department of Biology, University of Konstanz, Constance, Germany
| | - Jasmin Frey
- Department of Biology, University of Konstanz, Constance, Germany
| | - Paolo Franchini
- Department of Biology, University of Konstanz, Constance, Germany
| | - David Schleheck
- Department of Biology, University of Konstanz, Constance, Germany.,Konstanz Research School Chemical Biology, University of Konstanz, Constance, Germany
| | - Nicolai Müller
- Department of Biology, University of Konstanz, Constance, Germany
| | - Bernhard Schink
- Department of Biology, University of Konstanz, Constance, Germany.,Konstanz Research School Chemical Biology, University of Konstanz, Constance, Germany
| |
Collapse
|
11
|
Aromokeye DA, Oni OE, Tebben J, Yin X, Richter-Heitmann T, Wendt J, Nimzyk R, Littmann S, Tienken D, Kulkarni AC, Henkel S, Hinrichs KU, Elvert M, Harder T, Kasten S, Friedrich MW. Crystalline iron oxides stimulate methanogenic benzoate degradation in marine sediment-derived enrichment cultures. THE ISME JOURNAL 2021; 15:965-980. [PMID: 33154547 PMCID: PMC8115662 DOI: 10.1038/s41396-020-00824-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 10/09/2020] [Accepted: 10/22/2020] [Indexed: 01/29/2023]
Abstract
Elevated dissolved iron concentrations in the methanic zone are typical geochemical signatures of rapidly accumulating marine sediments. These sediments are often characterized by co-burial of iron oxides with recalcitrant aromatic organic matter of terrigenous origin. Thus far, iron oxides are predicted to either impede organic matter degradation, aiding its preservation, or identified to enhance organic carbon oxidation via direct electron transfer. Here, we investigated the effect of various iron oxide phases with differing crystallinity (magnetite, hematite, and lepidocrocite) during microbial degradation of the aromatic model compound benzoate in methanic sediments. In slurry incubations with magnetite or hematite, concurrent iron reduction, and methanogenesis were stimulated during accelerated benzoate degradation with methanogenesis as the dominant electron sink. In contrast, with lepidocrocite, benzoate degradation, and methanogenesis were inhibited. These observations were reproducible in sediment-free enrichments, even after five successive transfers. Genes involved in the complete degradation of benzoate were identified in multiple metagenome assembled genomes. Four previously unknown benzoate degraders of the genera Thermincola (Peptococcaceae, Firmicutes), Dethiobacter (Syntrophomonadaceae, Firmicutes), Deltaproteobacteria bacteria SG8_13 (Desulfosarcinaceae, Deltaproteobacteria), and Melioribacter (Melioribacteraceae, Chlorobi) were identified from the marine sediment-derived enrichments. Scanning electron microscopy (SEM) and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) images showed the ability of microorganisms to colonize and concurrently reduce magnetite likely stimulated by the observed methanogenic benzoate degradation. These findings explain the possible contribution of organoclastic reduction of iron oxides to the elevated dissolved Fe2+ pool typically observed in methanic zones of rapidly accumulating coastal and continental margin sediments.
Collapse
Affiliation(s)
- David A. Aromokeye
- grid.7704.40000 0001 2297 4381Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany ,grid.7704.40000 0001 2297 4381MARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Oluwatobi E. Oni
- grid.7704.40000 0001 2297 4381Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany
| | - Jan Tebben
- grid.10894.340000 0001 1033 7684Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Xiuran Yin
- grid.7704.40000 0001 2297 4381Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany ,grid.7704.40000 0001 2297 4381MARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Tim Richter-Heitmann
- grid.7704.40000 0001 2297 4381Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany
| | - Jenny Wendt
- grid.7704.40000 0001 2297 4381MARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany ,grid.7704.40000 0001 2297 4381Faculty of Geosciences, University of Bremen, Bremen, Germany
| | - Rolf Nimzyk
- grid.7704.40000 0001 2297 4381Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany
| | - Sten Littmann
- grid.419529.20000 0004 0491 3210Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Daniela Tienken
- grid.419529.20000 0004 0491 3210Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Ajinkya C. Kulkarni
- grid.7704.40000 0001 2297 4381Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany
| | - Susann Henkel
- grid.7704.40000 0001 2297 4381MARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany ,grid.10894.340000 0001 1033 7684Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Kai-Uwe Hinrichs
- grid.7704.40000 0001 2297 4381MARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany ,grid.7704.40000 0001 2297 4381Faculty of Geosciences, University of Bremen, Bremen, Germany
| | - Marcus Elvert
- grid.7704.40000 0001 2297 4381MARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany ,grid.7704.40000 0001 2297 4381Faculty of Geosciences, University of Bremen, Bremen, Germany
| | - Tilmann Harder
- grid.7704.40000 0001 2297 4381Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany ,grid.10894.340000 0001 1033 7684Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Sabine Kasten
- grid.7704.40000 0001 2297 4381MARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany ,grid.10894.340000 0001 1033 7684Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany ,grid.7704.40000 0001 2297 4381Faculty of Geosciences, University of Bremen, Bremen, Germany
| | - Michael W. Friedrich
- grid.7704.40000 0001 2297 4381Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany ,grid.7704.40000 0001 2297 4381MARUM—Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| |
Collapse
|
12
|
Murphy TR, Xiao R, Hamilton-Brehm SD. Hybrid genome de novo assembly with methylome analysis of the anaerobic thermophilic subsurface bacterium Thermanaerosceptrum fracticalcis strain DRI-13 T. BMC Genomics 2021; 22:209. [PMID: 33757423 PMCID: PMC7988955 DOI: 10.1186/s12864-021-07535-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/15/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND There is a dearth of sequenced and closed microbial genomes from environments that exceed > 500 m below level terrestrial surface. Coupled with even fewer cultured isolates, study and understanding of how life endures in the extreme oligotrophic subsurface environments is greatly hindered. Using a de novo hybrid assembly of Illumina and Oxford Nanopore sequences we produced a circular genome with corresponding methylome profile of the recently characterized thermophilic, anaerobic, and fumarate-respiring subsurface bacterium, Thermanaerosceptrum fracticalcis, strain DRI-13T to understand how this microorganism survives the deep subsurface. RESULTS The hybrid assembly produced a single circular genome of 3.8 Mb in length with an overall GC content of 45%. Out of the total 4022 annotated genes, 3884 are protein coding, 87 are RNA encoding genes, and the remaining 51 genes were associated with regulatory features of the genome including riboswitches and T-box leader sequences. Approximately 24% of the protein coding genes were hypothetical. Analysis of strain DRI-13T genome revealed: 1) energy conservation by bifurcation hydrogenase when growing on fumarate, 2) four novel bacterial prophages, 3) methylation profile including 76.4% N6-methyladenine and 3.81% 5-methylcytosine corresponding to novel DNA methyltransferase motifs. As well a cluster of 45 genes of unknown protein families that have enriched DNA mCpG proximal to the transcription start sites, and 4) discovery of a putative core of bacteriophage exclusion (BREX) genes surrounded by hypothetical proteins, with predicted functions as helicases, nucleases, and exonucleases. CONCLUSIONS The de novo hybrid assembly of strain DRI-13T genome has provided a more contiguous and accurate view of the subsurface bacterium T. fracticalcis, strain DRI-13T. This genome analysis reveals a physiological focus supporting syntrophy, non-homologous double stranded DNA repair, mobility/adherence/chemotaxis, unique methylome profile/recognized motifs, and a BREX defense system. The key to microbial subsurface survival may not rest on genetic diversity, but rather through specific syntrophy niches and novel methylation strategies.
Collapse
Affiliation(s)
- Trevor R Murphy
- Department of Microbiology, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Rui Xiao
- Department of Microbiology, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Scott D Hamilton-Brehm
- Department of Microbiology, Southern Illinois University Carbondale, Carbondale, IL, USA.
| |
Collapse
|
13
|
Omae K, Oguro T, Inoue M, Fukuyama Y, Yoshida T, Sako Y. Diversity analysis of thermophilic hydrogenogenic carboxydotrophs by carbon monoxide dehydrogenase amplicon sequencing using new primers. Extremophiles 2021; 25:61-76. [PMID: 33415441 PMCID: PMC7811984 DOI: 10.1007/s00792-020-01211-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 11/23/2020] [Indexed: 11/16/2022]
Abstract
The microbial H2-producing (hydrogenogenic) carbon monoxide (CO)-oxidizing activity by the membrane-associated CO dehydrogenase (CODH)/energy-converting hydrogenase (ECH) complex is an important metabolic process in the microbial community. However, the studies on hydrogenogenic carboxydotrophs had to rely on inherently cultivation and isolation methods due to their rare abundance, which was a bottleneck in ecological study. Here, we provided gene-targeted sequencing method for the diversity estimation of thermophilic hydrogenogenic carboxydotrophs. We designed six new degenerate primer pairs which effectively amplified the coding regions of CODH genes forming gene clusters with ECH genes (CODHech genes) in Firmicutes which includes major thermophilic hydrogenogenic carboxydotrophs in terrestrial thermal habitats. Amplicon sequencing by these primers using DNAs from terrestrial hydrothermal sediments and CO-gas-incubated samples specifically detected multiple CODH genes which were identical or phylogenetically related to the CODHech genes in Firmictes. Furthermore, we found that phylogenetically distinct CODHech genes were enriched in CO-gas-incubated samples, suggesting that our primers detected uncultured hydrogenogenic carboxydotrophs as well. The new CODH-targeted primers provided us with a fine-grained (~ 97.9% in nucleotide sequence identity) diversity analysis of thermophilic hydrogenogenic carboxydotrophs by amplicon sequencing and will bolster the ecological study of these microorganisms.
Collapse
Affiliation(s)
- Kimiho Omae
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Tatsuki Oguro
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Masao Inoue
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Yuto Fukuyama
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.,Research Center for Bioscience and Nanoscience, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, Kanagawa, 237-0061, Japan
| | - Takashi Yoshida
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.
| | - Yoshihiko Sako
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan
| |
Collapse
|
14
|
Podosokorskaya OA, Kochetkova TV, Novikov AA, Toshchakov SV, Elcheninov AG, Kublanov IV. Tenuifilum thalassicum gen. nov., sp. nov., a novel moderate thermophilic anaerobic bacterium from a Kunashir Island shallow hot spring representing a new family Tenuifilaceae fam. nov. in the class Bacteroidia. Syst Appl Microbiol 2020; 43:126126. [DOI: 10.1016/j.syapm.2020.126126] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/15/2020] [Accepted: 07/16/2020] [Indexed: 01/23/2023]
|
15
|
Aerobic microbial life persists in oxic marine sediment as old as 101.5 million years. Nat Commun 2020; 11:3626. [PMID: 32724059 PMCID: PMC7387439 DOI: 10.1038/s41467-020-17330-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 06/22/2020] [Indexed: 01/20/2023] Open
Abstract
Sparse microbial populations persist from seafloor to basement in the slowly accumulating oxic sediment of the oligotrophic South Pacific Gyre (SPG). The physiological status of these communities, including their substrate metabolism, is previously unconstrained. Here we show that diverse aerobic members of communities in SPG sediments (4.3‒101.5 Ma) are capable of readily incorporating carbon and nitrogen substrates and dividing. Most of the 6986 individual cells analyzed with nanometer-scale secondary ion mass spectrometry (NanoSIMS) actively incorporated isotope-labeled substrates. Many cells responded rapidly to incubation conditions, increasing total numbers by 4 orders of magnitude and taking up labeled carbon and nitrogen within 68 days after incubation. The response was generally faster (on average, 3.09 times) for nitrogen incorporation than for carbon incorporation. In contrast, anaerobic microbes were only minimally revived from this oxic sediment. Our results suggest that microbial communities widely distributed in organic-poor abyssal sediment consist mainly of aerobes that retain their metabolic potential under extremely low-energy conditions for up to 101.5 Ma. The discovery of aerobic microbial communities in nutrient-poor sediments below the seafloor begs the question of the mechanisms for their persistence. Here the authors investigate subseafloor sediment in the South Pacific Gyre abyssal plain, showing that aerobic microbial life can be revived and retain metabolic potential even from 101.5 Ma-old sediment.
Collapse
|
16
|
Gupta A, Sar P. Characterization and application of an anaerobic, iron and sulfate reducing bacterial culture in enhanced bioremediation of acid mine drainage impacted soil. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2020; 55:464-482. [PMID: 31971065 DOI: 10.1080/10934529.2019.1709362] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
Development of an appropriate bioremediation strategy for acid mine drainage (AMD) impacted environment is imperative for sustainable mining but remained critically challenged due to the paucity of knowledge on desired microbiological factors and their nutrient requirements. The present study was conducted to utilize the potential of an anaerobic, acid-tolerant, Fe3+ and SO42- reducing microbial consortium for in situ remediation of highly acidic (pH 3.21), SO42- rich (6285 mg/L) mine drainage impacted soil (AIS). A microbial consortium enriched from AMD system and composed of Clostridiales and Bacillales members was characterized and tested for in situ application through microcosms. A combination of bioaugmentation (enriched consortium) and biostimulation (cellulose) allowed 97% reduction in dissolved sulfate and rise in pH up to 7.5. 16S rRNA gene-based amplicon sequencing confirmed that although the bioaugmented community could survive in AIS, availability of carbon source was necessary for superior iron- and sulfate- reduction. Quantitative PCR of dsrB gene confirmed the role of carbon source in boosting the SO42- reduction activities of sulfate reducers. This study demonstrated that native AIS harbored limited catabolic activities required for the remediation but addition of catabolically active microbial populations along with necessary carbon and energy source facilitate the bioremediation of AIS.
Collapse
Affiliation(s)
- Abhishek Gupta
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Pinaki Sar
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
| |
Collapse
|
17
|
Fukuyama Y, Inoue M, Omae K, Yoshida T, Sako Y. Anaerobic and hydrogenogenic carbon monoxide-oxidizing prokaryotes: Versatile microbial conversion of a toxic gas into an available energy. ADVANCES IN APPLIED MICROBIOLOGY 2020; 110:99-148. [PMID: 32386607 DOI: 10.1016/bs.aambs.2019.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Carbon monoxide (CO) is a gas that is toxic to various organisms including humans and even microbes; however, it has low redox potential, which can fuel certain microbes, namely, CO oxidizers. Hydrogenogenic CO oxidizers utilize an energy conservation system via a CO dehydrogenase/energy-converting hydrogenase complex to produce hydrogen gas, a zero emission fuel, by CO oxidation coupled with proton reduction. Biochemical and molecular biological studies using a few model organisms have revealed their enzymatic reactions and transcriptional response mechanisms using CO. Biotechnological studies for CO-dependent hydrogen production have also been carried out with these model organisms. In this chapter, we review recent advances in the studies of these microbes, which reveal their unique and versatile metabolic profiles and provides future perspectives on ecological roles and biotechnological applications. Over the past decade, the number of isolates has doubled (37 isolates in 5 phyla, 20 genera, and 32 species). Some of the recently isolated ones show broad specificity to electron acceptors. Moreover, accumulating genomic information predicts their unique physiologies and reveals their phylogenomic relationships with novel potential hydrogenogenic CO oxidizers. Combined with genomic database surveys, a molecular ecological study has unveiled the wide distribution and low abundance of these microbes. Finally, recent biotechnological applications of hydrogenogenic CO oxidizers have been achieved via diverse approaches (e.g., metabolic engineering and co-cultivation), and the identification of thermophilic facultative anaerobic CO oxidizers will promote industrial applications as oxygen-tolerant biocatalysts for efficient hydrogen production by genomic engineering.
Collapse
Affiliation(s)
- Yuto Fukuyama
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Masao Inoue
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kimiho Omae
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takashi Yoshida
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yoshihiko Sako
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
| |
Collapse
|
18
|
Gustave W, Yuan ZF, Sekar R, Ren YX, Liu JY, Zhang J, Chen Z. Soil organic matter amount determines the behavior of iron and arsenic in paddy soil with microbial fuel cells. CHEMOSPHERE 2019; 237:124459. [PMID: 31377597 DOI: 10.1016/j.chemosphere.2019.124459] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 06/19/2019] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
Arsenic (As) mobility in paddy soils is mainly controlled by iron (Fe) oxides and iron reducing bacteria (IBR). The Fe reducing bacteria are also considered to be enriched on the anode of soil microbial fuel cells (sMFC). Thus, the sMFC may have an impact on elements' behavior, especially Fe and As, mobilization and immobilization in paddy soils. In this study, we found dissolved organic matter (DOC) abundance was a major determinate for the sMFC impact on Fe and As. In the constructed sMFCs with and without water management, distinctive behaviors of Fe and As in paddy soil were observed, which can be explained by the low or high DOC content under different water management. When the sMFC was deployed without water management, i.e. DOC was abundant, the sMFC promoted Fe and As movement into the soil porewater. The As release into the porewater was associated with the enhanced Fe reduction by the sMFC. This was ascribed to the acidification effect of sMFC anode and the increase of Fe reducing bacteria in the sMFC anode vicinity and associated bulk soil. However, when the sMFC was coupled with alternating dry-wet cycles, i.e. DOC was limited, the Fe and As concentrations in the soil porewater dramatically decreased by up to 2.3 and 1.6 fold, respectively, compared to the controls under the same water management regime. This study implies an environmental risk for the in-situ application of sMFC in organic matter rich wetlands and also points out a new mitigation strategy for As management in paddy soils.
Collapse
Affiliation(s)
- Williamson Gustave
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China; Department of Environmental Science, University of Liverpool, Brownlow Hill, Liverpool, L69 7ZX, United Kingdom; The School of Chemistry, Environmental & Life Sciences, University of The Bahamas, New Providence, Nassau, Bahamas
| | - Zhao-Feng Yuan
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China; Department of Environmental Science, University of Liverpool, Brownlow Hill, Liverpool, L69 7ZX, United Kingdom
| | - Raju Sekar
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, 215123, China
| | - Yu-Xiang Ren
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China
| | - Jinjing-Yuan Liu
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China
| | - Jun Zhang
- Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zheng Chen
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, 215123, China.
| |
Collapse
|
19
|
Rubiano-Labrador C, Díaz-Cárdenas C, López G, Gómez J, Baena S. Colombian Andean thermal springs: reservoir of thermophilic anaerobic bacteria producing hydrolytic enzymes. Extremophiles 2019; 23:793-808. [PMID: 31555903 DOI: 10.1007/s00792-019-01132-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 09/13/2019] [Indexed: 11/25/2022]
Abstract
Anaerobic cultivable microbial communities in thermal springs producing hydrolytic enzymes were studied. Thermal water samples from seven thermal springs located in the Andean volcanic belt, in the eastern and central mountain ranges of the Colombian Andes were used as inocula for the growth and isolation of thermophilic microorganisms using substrates such as starch, gelatin, xylan, cellulose, Tween 80, olive oil, peptone and casamino acids. These springs differed in temperature (50-70 °C) and pH (6.5-7.5). The predominant ion in eastern mountain range thermal springs was sulphate, whereas that in central mountain range springs was bicarbonate. A total of 40 anaerobic thermophilic bacterial strains that belonged to the genera Thermoanaerobacter, Caloramator, Anoxybacillus, Caloranaerobacter, Desulfomicrobium, Geotoga, Hydrogenophilus, Desulfacinum and Thermoanaerobacterium were isolated. To investigate the metabolic potential of these isolates, selected strains were analysed for enzymatic activities to identify strains than can produce hydrolytic enzymes. We demonstrated that these thermal springs contained diverse microbial populations of anaerobic thermophilic comprising different metabolic groups of bacteria including strains belonging to the genera Thermoanaerobacter, Caloramator, Anoxybacillus, Caloranaerobacter, Desulfomicrobium, Geotoga, Hydrogenophilus, Desulfacinum and Thermoanaerobacterium with amylases, proteases, lipases, esterases, xylanases and pectinases; therefore, the strains represent a promising source of enzymes with biotechnological potential.
Collapse
Affiliation(s)
- Carolina Rubiano-Labrador
- Unidad de Saneamiento y Biotecnología Ambiental, Departamento de Biología, Pontificia Universidad Javeriana, 56710, Bogotá DC, Colombia
- Facultad de Ciencias Básicas, Universidad Tecnológica de Bolívar, Cartagena de Indias D.T. y C., Colombia
| | - Carolina Díaz-Cárdenas
- Unidad de Saneamiento y Biotecnología Ambiental, Departamento de Biología, Pontificia Universidad Javeriana, 56710, Bogotá DC, Colombia.
| | - Gina López
- Unidad de Saneamiento y Biotecnología Ambiental, Departamento de Biología, Pontificia Universidad Javeriana, 56710, Bogotá DC, Colombia
| | - Javier Gómez
- Unidad de Saneamiento y Biotecnología Ambiental, Departamento de Biología, Pontificia Universidad Javeriana, 56710, Bogotá DC, Colombia
| | - Sandra Baena
- Unidad de Saneamiento y Biotecnología Ambiental, Departamento de Biología, Pontificia Universidad Javeriana, 56710, Bogotá DC, Colombia
| |
Collapse
|
20
|
How Thermophilic Gram-Positive Organisms Perform Extracellular Electron Transfer: Characterization of the Cell Surface Terminal Reductase OcwA. mBio 2019; 10:mBio.01210-19. [PMID: 31431546 PMCID: PMC6703420 DOI: 10.1128/mbio.01210-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Thermophilic Gram-positive organisms were recently shown to be a promising class of organisms to be used in bioelectrochemical systems for the production of electrical energy. These organisms present a thick peptidoglycan layer that was thought to preclude them to perform extracellular electron transfer (i.e., exchange catabolic electrons with solid electron acceptors outside the cell). In this paper, we describe the structure and functional mechanisms of the multiheme cytochrome OcwA, the terminal reductase of the Gram-positive bacterium Thermincola potens JR found at the cell surface of this organism. The results presented here show that this protein can take the role of a respiratory “Swiss Army knife,” allowing this organism to grow in environments with soluble and insoluble substrates. Moreover, it is shown that it is unrelated to terminal reductases found at the cell surface of other electroactive organisms. Instead, OcwA is similar to terminal reductases of soluble electron acceptors. Our data reveal that terminal oxidoreductases of soluble and insoluble substrates are evolutionarily related, providing novel insights into the evolutionary pathway of multiheme cytochromes. Extracellular electron transfer is the key process underpinning the development of bioelectrochemical systems for the production of energy or added-value compounds. Thermincola potens JR is a promising Gram-positive bacterium to be used in these systems because it is thermophilic. In this paper, we describe the structural and functional properties of the nonaheme cytochrome OcwA, which is the terminal reductase of this organism. The structure of OcwA, determined at 2.2-Å resolution, shows that the overall fold and organization of the hemes are not related to other metal reductases and instead are similar to those of multiheme cytochromes involved in the biogeochemical cycles of nitrogen and sulfur. We show that, in addition to solid electron acceptors, OcwA can also reduce soluble electron shuttles and oxyanions. These data reveal that OcwA can work as a multipurpose respiratory enzyme allowing this organism to grow in environments with rapidly changing availability of terminal electron acceptors without the need for transcriptional regulation and protein synthesis.
Collapse
|
21
|
Xu JX, Li XM, Sun GX, Cui L, Ding LJ, He C, Li LG, Shi Q, Smets BF, Zhu YG. Fate of Labile Organic Carbon in Paddy Soil Is Regulated by Microbial Ferric Iron Reduction. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:8533-8542. [PMID: 31269402 DOI: 10.1021/acs.est.9b01323] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Global paddy soil is the primary source of methane, a potent greenhouse gas. It is therefore highly important to understand the carbon cycling in paddy soil. Microbial reduction of iron, which is widely found in paddy soil, is likely coupled with the oxidation of dissolved organic matter (DOM) and suppresses methanogenesis. However, little is known about the biotransformation of small molecular DOM accumulated under flooded conditions and the effect of iron reduction on the biotransformation pathway. Here, we carried out anaerobic incubation experiments using field-collected samples amended with ferrihydrite and different short-chain fatty acids. Our results showed that less than 20% of short-chain fatty acids were mineralized and released to the atmosphere. Using Fourier transform ion cyclotron resonance mass spectrometry, we further found that a large number of recalcitrant molecules were produced during microbial consumption of these short-chain fatty acids. Moreover, the biotransformation efficiency of short-chain fatty acids decreased with the increasing length of carbon chains. Ferrihydrite addition promoted microbial assimilation of short-chain fatty acids as well as enhanced the activation and biotransformation of indigenous stable carbon in the soil replenished with formate. This study demonstrates the significance of ferrihydrite in the biotransformation of labile DOM and promotes a more comprehensive understanding of the coupling of iron reduction and carbon cycling in paddy soils.
Collapse
Affiliation(s)
- Jian-Xin Xu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , People's Republic of China
- Department of Environmental Engineering , Technical University of Denmark , 2800 Kongens Lyngby , Denmark
- Sino-Danish College of University of Chinese Academy of Sciences , Beijing 101400 , People's Republic of China
- Sino-Danish Centre for Education and Research , Beijing 100049 , People's Republic of China
| | - Xiao-Ming Li
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , People's Republic of China
- University of Chinese Academy of Sciences , Beijing 100049 , People's Republic of China
| | - Guo-Xin Sun
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , People's Republic of China
- University of Chinese Academy of Sciences , Beijing 100049 , People's Republic of China
| | - Li Cui
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment , Chinese Academy of Sciences , Xiamen , Fujian 361021 , People's Republic of China
| | - Long-Jun Ding
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , People's Republic of China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing , China University of Petroleum , Beijing 102249 , People's Republic of China
| | - Li-Guan Li
- Department of Environmental Engineering , Technical University of Denmark , 2800 Kongens Lyngby , Denmark
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing , China University of Petroleum , Beijing 102249 , People's Republic of China
| | - Barth F Smets
- Department of Environmental Engineering , Technical University of Denmark , 2800 Kongens Lyngby , Denmark
| | - Yong-Guan Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , People's Republic of China
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment , Chinese Academy of Sciences , Xiamen , Fujian 361021 , People's Republic of China
- University of Chinese Academy of Sciences , Beijing 100049 , People's Republic of China
| |
Collapse
|
22
|
Electron Donor Utilization and Secondary Mineral Formation during the Bioreduction of Lepidocrocite by Shewanella putrefaciens CN32. MINERALS 2019. [DOI: 10.3390/min9070434] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The bioreduction of Fe(III) oxides by dissimilatory iron reducing bacteria (DIRB) may result in the production of a suite of Fe(II)-bearing secondary minerals, including magnetite, siderite, vivianite, green rusts, and chukanovite; the formation of specific phases controlled by the interaction of various physiological and geochemical factors. In an effort to better understand the effects of individual electron donors on the formation of specific Fe(II)-bearing secondary minerals, we examined the effects of a series of potential electron donors on the bioreduction of lepidocrocite (γ-FeOOH) by Shewanella putrefaciens CN32. Biomineralization products were identified by X-ray diffraction, Mössbauer spectroscopy, and scanning electron microscopy. Acetate, citrate, ethanol, glucose, glutamate, glycerol, malate, and succinate were not effectively utilized for the bioreduction of lepidocrocite by S. putrefaciens CN32; however, substantial Fe(II) production was observed when formate, lactate, H2, pyruvate, serine, or N acetylglucosamine (NAG) was provided as an electron donor. Carbonate or sulfate green rust was the dominant Fe(II)-bearing secondary mineral when formate, H2, lactate, or NAG was provided, however, siderite formed with pyruvate or serine. Geochemical modeling indicated that pH and carbonate concentration are the key factors determining the prevalence of carbonate green rust verses siderite.
Collapse
|
23
|
Omae K, Fukuyama Y, Yasuda H, Mise K, Yoshida T, Sako Y. Diversity and distribution of thermophilic hydrogenogenic carboxydotrophs revealed by microbial community analysis in sediments from multiple hydrothermal environments in Japan. Arch Microbiol 2019; 201:969-982. [PMID: 31030239 PMCID: PMC6687684 DOI: 10.1007/s00203-019-01661-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 03/15/2019] [Accepted: 04/15/2019] [Indexed: 12/18/2022]
Abstract
In hydrothermal environments, carbon monoxide (CO) utilisation by thermophilic hydrogenogenic carboxydotrophs may play an important role in microbial ecology by reducing toxic levels of CO and providing H2 for fuelling microbial communities. We evaluated thermophilic hydrogenogenic carboxydotrophs by microbial community analysis. First, we analysed the correlation between carbon monoxide dehydrogenase (CODH)–energy-converting hydrogenase (ECH) gene cluster and taxonomic affiliation by surveying an increasing genomic database. We identified 71 genome-encoded CODH–ECH gene clusters, including 46 whose owners were not reported as hydrogenogenic carboxydotrophs. We identified 13 phylotypes showing > 98.7% identity with these taxa as potential hydrogenogenic carboxydotrophs in hot springs. Of these, Firmicutes phylotypes such as Parageobacillus, Carboxydocella, Caldanaerobacter, and Carboxydothermus were found in different environmental conditions and distinct microbial communities. The relative abundance of the potential thermophilic hydrogenogenic carboxydotrophs was low. Most of them did not show any symbiotic networks with other microbes, implying that their metabolic activities might be low.
Collapse
Affiliation(s)
- Kimiho Omae
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8503, Japan
| | - Yuto Fukuyama
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8503, Japan
| | - Hisato Yasuda
- Center for Advanced Marine Core Research, Kochi University, B200 Monobe, Nankoku, Kochi, 783-8502, Japan
| | - Kenta Mise
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8503, Japan
| | - Takashi Yoshida
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8503, Japan
| | - Yoshihiko Sako
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8503, Japan.
| |
Collapse
|
24
|
Lusk BG. Thermophiles; or, the Modern Prometheus: The Importance of Extreme Microorganisms for Understanding and Applying Extracellular Electron Transfer. Front Microbiol 2019; 10:818. [PMID: 31080440 PMCID: PMC6497744 DOI: 10.3389/fmicb.2019.00818] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/01/2019] [Indexed: 11/30/2022] Open
Abstract
Approximately four billion years ago, the first microorganisms to thrive on earth were anaerobic chemoautotrophic thermophiles, a specific group of extremophiles that survive and operate at temperatures ∼50 – 125°C and do not use molecular oxygen (O2) for respiration. Instead, these microorganisms performed respiration via dissimilatory metal reduction by transferring their electrons extracellularly to insoluble electron acceptors. Genetic evidence suggests that Gram-positive thermophilic bacteria capable of extracellular electron transfer (EET) are positioned close to the root of the Bacteria kingdom on the tree of life. On the contrary, EET in Gram-negative mesophilic bacteria is a relatively new phenomenon that is evolutionarily distinct from Gram-positive bacteria. This suggests that EET evolved separately in Gram-positive thermophiles and Gram-negative mesophiles, and that EET in these bacterial types is a result of a convergent evolutionary process leading to homoplasy. Thus, the study of dissimilatory metal reducing thermophiles provides a glimpse into some of Earth’s earliest forms of respiration. This will provide new insights for understanding biogeochemistry and the development of early Earth in addition to providing unique avenues for exploration and discovery in astrobiology. Lastly, the physiological composition of Gram-positive thermophiles, coupled with the kinetic and thermodynamic consequences of surviving at elevated temperatures, makes them ideal candidates for developing new mathematical models and designing innovative next-generation biotechnologies. KEY CONCEPTS Anaerobe: organism that does not require oxygen for growth. Chemoautotroph: organism that obtains energy by oxidizing inorganic electron donors. Convergent Evolution: process in which organisms which are not closely related independently evolve similar traits due to adapting to similar ecological niches and/or environments. Dissimilatory Metal Reduction: reduction of a metal or metalloid that uses electrons from oxidized organic or inorganic electron donors. Exoelectrogen: microorganism that performs dissimilatory metal reduction via extracellular electron transfer. Extremophiles: organisms that thrive in physical or geochemical conditions that are considered detrimental to most life on Earth. Homoplasy: a character shared by a set of species that is not shared by a common ancestor Non-synonymous Substitutions (Ka): a substitution of a nucleotide that changes a codon sequence resulting in a change in the amino acid sequence of a protein. Synonymous Substitutions (Ks): a substitution of a nucleotide that may change a codon sequence, but results in no change in the amino acid sequence of a protein. Thermophiles: a specific group of extremophiles that survive and operate at temperatures ∼50–125°C.
Collapse
|
25
|
Kato S, Wada K, Kitagawa W, Mayumi D, Ikarashi M, Sone T, Asano K, Kamagata Y. Conductive Iron Oxides Promote Methanogenic Acetate Degradation by Microbial Communities in a High-Temperature Petroleum Reservoir. Microbes Environ 2019; 34:95-98. [PMID: 30773516 PMCID: PMC6440731 DOI: 10.1264/jsme2.me18140] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Supplementation with conductive magnetite particles promoted methanogenic acetate degradation by microbial communities enriched from the production water of a high-temperature petroleum reservoir. A microbial community analysis revealed that Petrothermobacter spp. (phylum Deferribacteres), known as thermophilic Fe(III) reducers, predominated in the magnetite-supplemented enrichment, whereas other types of Fe(III) reducers, such as Thermincola spp. and Thermotoga spp., were dominant under ferrihydrite-reducing conditions. These results suggest that magnetite induced interspecies electron transfer via electric currents through conductive particles between Petrothermobacter spp. and methanogens. This is the first evidence for possible electric syntrophy in high-temperature subsurface environments.
Collapse
Affiliation(s)
- Souichiro Kato
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University.,Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
| | - Kaoru Wada
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University
| | - Wataru Kitagawa
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University.,Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
| | | | | | - Teruo Sone
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University
| | - Kozo Asano
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University
| | - Yoichi Kamagata
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University.,Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST).,Bioproduction Research Institute, AIST
| |
Collapse
|
26
|
Gupta A, Dutta A, Sarkar J, Panigrahi MK, Sar P. Low-Abundance Members of the Firmicutes Facilitate Bioremediation of Soil Impacted by Highly Acidic Mine Drainage From the Malanjkhand Copper Project, India. Front Microbiol 2018; 9:2882. [PMID: 30619102 PMCID: PMC6297179 DOI: 10.3389/fmicb.2018.02882] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 11/12/2018] [Indexed: 11/16/2022] Open
Abstract
Sulfate- and iron-reducing heterotrophic bacteria represented minor proportion of the indigenous microbial community of highly acidic, oligotrophic acid mine drainage (AMD), but they can be successfully stimulated for in situ bioremediation of an AMD impacted soil (AIS). These anaerobic microorganisms although played central role in sulfate- and metal-removal, they remained inactive in the AIS due to the paucity of organic carbon and extreme acidity of the local environment. The present study investigated the scope for increasing the abundance and activity of inhabitant sulfate- and iron-reducing bacterial populations of an AIS from Malanjkhand Copper Project. An AIS of pH 3.5, high soluble SO4 2- (7838 mg/l) and Fe (179 mg/l) content was amended with nutrients (cysteine and lactate). Thorough geochemical analysis, 16S rRNA gene amplicon sequencing and qPCR highlighted the intrinsic metabolic abilities of native bacteria in AMD bioremediation. Following 180 days incubation, the nutrient amended AIS showed marked increase in pH (to 6.6) and reduction in soluble -SO4 2- (95%), -Fe (50%) and other heavy metals. Concomitant to physicochemical changes a vivid shift in microbial community composition was observed. Members of the Firmicutes present as a minor group (1.5% of total community) in AIS emerged as the single most abundant taxon (∼56%) following nutrient amendments. Organisms affiliated to Clostridiaceae, Peptococcaceae, Veillonellaceae, Christensenellaceae, Lachnospiraceae, Bacillaceae, etc. known for their fermentative, iron and sulfate reducing abilities were prevailed in the amended samples. qPCR data corroborated with this change and further revealed an increase in abundance of dissimilatory sulfite reductase gene (dsrB) and specific bacterial taxa. Involvement of these enhanced populations in reductive processes was validated by further enrichments and growth in sulfate- and iron-reducing media. Amplicon sequencing of these enrichments confirmed growth of Firmicutes members and proved their sulfate- and iron-reduction abilities. This study provided a better insight on ecological perspective of Firmicutes members within the AMD impacted sites, particularly their involvement in sulfate- and iron-reduction processes, in situ pH management and bioremediation.
Collapse
Affiliation(s)
- Abhishek Gupta
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Avishek Dutta
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Jayeeta Sarkar
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Mruganka Kumar Panigrahi
- Department of Geology and Geophysics, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Pinaki Sar
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, India
| |
Collapse
|
27
|
Vuillemin A, Horn F, Friese A, Winkel M, Alawi M, Wagner D, Henny C, Orsi WD, Crowe SA, Kallmeyer J. Metabolic potential of microbial communities from ferruginous sediments. Environ Microbiol 2018; 20:4297-4313. [PMID: 29968357 DOI: 10.1111/1462-2920.14343] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/22/2018] [Accepted: 06/25/2018] [Indexed: 01/22/2023]
Abstract
Ferruginous (Fe-rich, SO4 -poor) conditions are generally restricted to freshwater sediments on Earth today, but were likely widespread during the Archean and Proterozoic Eons. Lake Towuti, Indonesia, is a large ferruginous lake that likely hosts geochemical processes analogous to those that operated in the ferruginous Archean ocean. The metabolic potential of microbial communities and related biogeochemical cycling under such conditions remain largely unknown. We combined geochemical measurements (pore water chemistry, sulfate reduction rates) with metagenomics to link metabolic potential with geochemical processes in the upper 50 cm of sediment. Microbial diversity and quantities of genes for dissimilatory sulfate reduction (dsrAB) and methanogenesis (mcrA) decrease with increasing depth, as do rates of potential sulfate reduction. The presence of taxa affiliated with known iron- and sulfate-reducers implies potential use of ferric iron and sulfate as electron acceptors. Pore-water concentrations of acetate imply active production through fermentation. Fermentation likely provides substrates for respiration with iron and sulfate as electron donors and for methanogens that were detected throughout the core. The presence of ANME-1 16S and mcrA genes suggests potential for anaerobic methane oxidation. Overall our data suggest that microbial community metabolism in anoxic ferruginous sediments support coupled Fe, S and C biogeochemical cycling.
Collapse
Affiliation(s)
- Aurèle Vuillemin
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3: Geomicrobiology, Potsdam, Germany.,Department of Earth & Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Fabian Horn
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3: Geomicrobiology, Potsdam, Germany
| | - André Friese
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3: Geomicrobiology, Potsdam, Germany
| | - Matthias Winkel
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3: Geomicrobiology, Potsdam, Germany
| | - Mashal Alawi
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3: Geomicrobiology, Potsdam, Germany
| | - Dirk Wagner
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3: Geomicrobiology, Potsdam, Germany.,University of Potsdam, Faculty of Mathematics and Natural Sciences, Institute of Earth and Environmental Sciences, Potsdam, Germany
| | - Cynthia Henny
- Research Center for Limnology (LIPI), Indonesian Institute of Sciences, Division of Inland Waterways Dynamics, Cibinong-Bogor, Indonesia
| | - William D Orsi
- Department of Earth & Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany.,Geobio-CenterLMU, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sean A Crowe
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada.,Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - Jens Kallmeyer
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3: Geomicrobiology, Potsdam, Germany
| |
Collapse
|
28
|
Wang Y, Li P, Jiang Z, Liu H, Wei D, Wang H, Wang Y. Diversity and abundance of arsenic methylating microorganisms in high arsenic groundwater from Hetao Plain of Inner Mongolia, China. ECOTOXICOLOGY (LONDON, ENGLAND) 2018; 27:1047-1057. [PMID: 29951795 DOI: 10.1007/s10646-018-1958-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/07/2018] [Indexed: 06/08/2023]
Abstract
Arsenic methylation is regarded as an effective way of arsenic detoxification. Current knowledge about arsenic biomethylation in high arsenic groundwater remains limited. In the present study, 16 high arsenic groundwater samples from deep wells of the Hetao Plain were investigated using clone library and quantitative polymerase chain reaction (qPCR) analyses of arsM genes as well as geochemical analysis. The concentrations of methylated arsenic (including monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA)) varied from 2.40 to 16.85 μg/L. Both bacterial and archaeal arsenic methylating populations were detected in the high arsenic aquifer. They were dominated by Proteobacteria, Firmicutes, Gemmatimonadetes, Nitrospirae, Methanomicrobia and a large unidentified group. The abundances of predominant populations were correlated positively to either total organic carbon or total arsenic and arsenite concentrations. The arsM gene abundances in high arsenic groundwater ranged from below detection to 5.71 × 106 copies/L and accounted for 0-3.32‰ of total bacterial and archaeal 16S rRNA genes. The arsM gene copies in high arsenic groundwater showed closely positive correlations with methylated arsenic concentrations. The overall results implied that arsenic methylating microorganisms were abundant and diverse in high arsenic groundwater. This was the first study of arsenic methylating microbial communities in high arsenic groundwater aquifers and might provide useful information for arsenic bioremediation in groundwater systems.
Collapse
Affiliation(s)
- Yanhong Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Ping Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China.
| | - Zhou Jiang
- School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Han Liu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Dazhun Wei
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Helin Wang
- School of Environmental Studies, China University of Geosciences, Wuhan, China
| | - Yanxin Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China.
- School of Environmental Studies, China University of Geosciences, Wuhan, China.
| |
Collapse
|
29
|
Toshchakov SV, Lebedinsky AV, Sokolova TG, Zavarzina DG, Korzhenkov AA, Teplyuk AV, Chistyakova NI, Rusakov VS, Bonch-Osmolovskaya EA, Kublanov IV, Gavrilov SN. Genomic Insights Into Energy Metabolism of Carboxydocella thermautotrophica Coupling Hydrogenogenic CO Oxidation With the Reduction of Fe(III) Minerals. Front Microbiol 2018; 9:1759. [PMID: 30123201 PMCID: PMC6085454 DOI: 10.3389/fmicb.2018.01759] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 07/13/2018] [Indexed: 01/17/2023] Open
Abstract
The genus Carboxydocella forms a deeply branching family in the class Clostridia and is currently represented by three physiologically diverse species of thermophilic prokaryotes. The type strain of the type species, Carboxydocella thermautotrophica 41T, is an obligate chemolithoautotroph growing exclusively by hydrogenogenic CO oxidation. Another strain, isolated from a hot spring at Uzon caldera, Kamchatka in the course of this work, is capable of coupling carboxydotrophy and dissimilatory reduction of Fe(III) from oxic and phyllosilicate minerals. The processes of carboxydotrophy and Fe(III) reduction appeared to be interdependent in this strain. The genomes of both isolates were sequenced, assembled into single chromosome sequences (for strain 41T a plasmid sequence was also assembled) and analyzed. Genome analysis revealed that each of the two strains possessed six genes encoding diverse Ni,Fe-containing CO dehydrogenases (maximum reported in complete prokaryotic genomes), indicating crucial role of carbon monoxide in C. thermautotrophica metabolism. Both strains possessed a set of 30 multiheme c-type cytochromes, but only the newly isolated Fe-reducing strain 019 had one extra gene of a 17-heme cytochrome, which is proposed to represent a novel determinant of dissimilatory iron reduction in prokaryotes. Mössbauer studies revealed that strain 019 induced reductive transformation of the abundant ferric/ferrous-mica mineral glauconite to siderite during carboxydotrophic growth. Reconstruction of the C. thermautotrophica strains energy metabolism is the first comprehensive genome analysis of a representative of the deep phylogenetic branch Clostridia Incertae Sedis, family V. Our data provide insights into energy metabolism of C. thermautotrophica with an emphasis on its ecological implications.
Collapse
Affiliation(s)
- Stepan V. Toshchakov
- Laboratory of Microbial Genomics, Immanuel Kant Baltic Federal University, Kaliningrad, Russia
- Winogradsky Institute of Microbiology, FRC Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Alexander V. Lebedinsky
- Winogradsky Institute of Microbiology, FRC Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Tatyana G. Sokolova
- Winogradsky Institute of Microbiology, FRC Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Daria G. Zavarzina
- Winogradsky Institute of Microbiology, FRC Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Alexei A. Korzhenkov
- Laboratory of Microbial Genomics, Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - Alina V. Teplyuk
- Laboratory of Microbial Genomics, Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | | | | | | | - Ilya V. Kublanov
- Winogradsky Institute of Microbiology, FRC Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Sergey N. Gavrilov
- Winogradsky Institute of Microbiology, FRC Biotechnology, Russian Academy of Sciences, Moscow, Russia
| |
Collapse
|
30
|
Dai K, Wen JL, Zhang F, Ma XW, Cui XY, Zhang Q, Zhao TJ, Zeng RJ. Electricity production and microbial characterization of thermophilic microbial fuel cells. BIORESOURCE TECHNOLOGY 2017; 243:512-519. [PMID: 28697453 DOI: 10.1016/j.biortech.2017.06.167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/23/2017] [Accepted: 06/29/2017] [Indexed: 06/07/2023]
Abstract
Thermophilic microbial fuel cell (TMFC) offers many benefits, but the investigations on the diversity of exoelectrogenic bacteria are scarce. In this study, a two-chamber TMFC was constructed using ethanol as an electron donor, and the microbial dynamics were analyzed by high-throughput sequencing and 16S rRNA clone-library sequencing. The open-circuit potential of TMFC was approximately 650mV, while the maximum voltage was around 550mV. The maximum power density was 437mW/m2, and the columbic efficiency in this work was 20.5±6.0%. The Firmicutes bacteria, related to the uncultured bacterium clone A55_D21_H_B_C01 with a similarity of 99%, accounted for 90.9% of all bacteria in the TMFC biofilm. This unknown bacterium has the potential to become a new thermophilic exoelectrogenic bacterium that is yet to be cultured. The development of TMFC-involved biotechnologies will be beneficial for the production of valuable chemicals and generation of energy in the future.
Collapse
Affiliation(s)
- Kun Dai
- Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, People's Republic of China
| | - Jun-Li Wen
- Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, People's Republic of China
| | - Fang Zhang
- Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, People's Republic of China.
| | - Xi-Wen Ma
- Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, People's Republic of China
| | - Xiang-Yu Cui
- Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, People's Republic of China
| | - Qi Zhang
- Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, People's Republic of China
| | - Ting-Jia Zhao
- Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, People's Republic of China
| | - Raymond J Zeng
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| |
Collapse
|
31
|
Bray MS, Wu J, Reed BC, Kretz CB, Belli KM, Simister RL, Henny C, Stewart FJ, DiChristina TJ, Brandes JA, Fowle DA, Crowe SA, Glass JB. Shifting microbial communities sustain multiyear iron reduction and methanogenesis in ferruginous sediment incubations. GEOBIOLOGY 2017; 15:678-689. [PMID: 28419718 PMCID: PMC7780294 DOI: 10.1111/gbi.12239] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 03/17/2017] [Indexed: 05/16/2023]
Abstract
Reactive Fe(III) minerals can influence methane (CH4 ) emissions by inhibiting microbial methanogenesis or by stimulating anaerobic CH4 oxidation. The balance between Fe(III) reduction, methanogenesis, and CH4 oxidation in ferruginous Archean and Paleoproterozoic oceans would have controlled CH4 fluxes to the atmosphere, thereby regulating the capacity for CH4 to warm the early Earth under the Faint Young Sun. We studied CH4 and Fe cycling in anoxic incubations of ferruginous sediment from the ancient ocean analogue Lake Matano, Indonesia, over three successive transfers (500 days in total). Iron reduction, methanogenesis, CH4 oxidation, and microbial taxonomy were monitored in treatments amended with ferrihydrite or goethite. After three dilutions, Fe(III) reduction persisted only in bottles with ferrihydrite. Enhanced CH4 production was observed in the presence of goethite, highlighting the potential for reactive Fe(III) oxides to inhibit methanogenesis. Supplementing the media with hydrogen, nickel and selenium did not stimulate methanogenesis. There was limited evidence for Fe(III)-dependent CH4 oxidation, although some incubations displayed CH4 -stimulated Fe(III) reduction. 16S rRNA profiles continuously changed over the course of enrichment, with ultimate dominance of unclassified members of the order Desulfuromonadales in all treatments. Microbial diversity decreased markedly over the course of incubation, with subtle differences between ferrihydrite and goethite amendments. These results suggest that Fe(III) oxide mineralogy and availability of electron donors could have led to spatial separation of Fe(III)-reducing and methanogenic microbial communities in ferruginous marine sediments, potentially explaining the persistence of CH4 as a greenhouse gas throughout the first half of Earth history.
Collapse
Affiliation(s)
- M. S. Bray
- School of Biology, Georgia Institute of Technology, Atlanta, GA, USA
| | - J. Wu
- School of Biology, Georgia Institute of Technology, Atlanta, GA, USA
| | - B. C. Reed
- School of Biology, Georgia Institute of Technology, Atlanta, GA, USA
| | - C. B. Kretz
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - K. M. Belli
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - R. L. Simister
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada
| | - C. Henny
- Research Center for Limnology, Indonesian Institute of Sciences, Cibinong, Indonesia
| | - F. J. Stewart
- School of Biology, Georgia Institute of Technology, Atlanta, GA, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - T. J. DiChristina
- School of Biology, Georgia Institute of Technology, Atlanta, GA, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - J. A. Brandes
- Skidaway Institute of Oceanography, Savannah, GA, USA
| | - D. A. Fowle
- Department of Geology, University of Kansas, Lawrence, KS, USA
| | - S. A. Crowe
- Departments of Microbiology & Immunology and Earth, Ocean, & Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada
| | - J. B. Glass
- School of Biology, Georgia Institute of Technology, Atlanta, GA, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| |
Collapse
|
32
|
Lusk BG, Colin A, Parameswaran P, Rittmann BE, Torres CI. Simultaneous fermentation of cellulose and current production with an enriched mixed culture of thermophilic bacteria in a microbial electrolysis cell. Microb Biotechnol 2017; 11:63-73. [PMID: 28557303 PMCID: PMC5743814 DOI: 10.1111/1751-7915.12733] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 12/16/2022] Open
Abstract
An enriched mixed culture of thermophilic (60°C) bacteria was assembled for the purpose of using cellulose to produce current in thermophilic microbial electrolysis cells (MECs). Cellulose was fermented into sugars and acids before being consumed by anode‐respiring bacteria (ARB) for current production. Current densities (j) were sustained at 6.5 ± 0.2 A m−2 in duplicate reactors with a coulombic efficiency (CE) of 84 ± 0.3%, a coulombic recovery (CR) of 54 ± 11% and without production of CH4. Low‐scan rate cyclic voltammetry (LSCV) revealed a mid‐point potential (Eka) of −0.17 V versus SHE. Pyrosequencing analysis of the V4 hypervariable region of 16S rDNA and scanning electron microscopy present an enriched thermophilic microbial community consisting mainly of the phylum Firmicutes with the Thermoanaerobacter (46 ± 13%) and Thermincola (28 ± 14%) genera occupying the biofilm anode in high relative abundance and Tepidmicrobium (38 ± 6%) and Moorella (11 ± 8%) genera present in high relative abundance in the bulk medium. The Thermoanaerobacter (15 ± 16%) and Brevibacillus (21 ± 30%) genera were also present in the bulk medium; however, their relative abundance varied by reactor. This study indicates that thermophilic consortia can obtain high CE and CR, while sustaining high current densities from cellulose in MECs.
Collapse
Affiliation(s)
- Bradley G Lusk
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, P.O. Box 875701, Tempe, AZ, 85287-5701, USA.,#ScienceTheEarth, Mesa, AZ, 85201, USA
| | - Alexandra Colin
- Ecole Normale Superieure, 45, rue d'Ulm, 75230, Paris Cedex 05, France
| | - Prathap Parameswaran
- Department of Civil Engineering, Kansas State University, 2123 Fiedler Hall, Manhattan, KS, 66502, USA
| | - Bruce E Rittmann
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, P.O. Box 875701, Tempe, AZ, 85287-5701, USA.,School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA
| | - Cesar I Torres
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, P.O. Box 875701, Tempe, AZ, 85287-5701, USA.,School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| |
Collapse
|
33
|
Lusk BG, Parameswaran P, Popat SC, Rittmann BE, Torres CI. The effect of pH and buffer concentration on anode biofilms of Thermincola ferriacetica. Bioelectrochemistry 2016; 112:47-52. [DOI: 10.1016/j.bioelechem.2016.07.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 07/17/2016] [Accepted: 07/18/2016] [Indexed: 11/16/2022]
|
34
|
Shkoporov AN, Efimov BA, Kondova I, Ouwerling B, Chaplin AV, Shcherbakova VA, Langermans JAM. Peptococcus simiae sp. nov., isolated from rhesus macaque faeces and emended description of the genus Peptococcus. Int J Syst Evol Microbiol 2016; 66:5187-5191. [PMID: 27613234 DOI: 10.1099/ijsem.0.001494] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A study of the faecal microbiome in three healthy female rhesus macaques revealed the presence of a novel obligately anaerobic, chemoorganoheterotrophic, non-sporing, coccoid, non-motile, Gram-stain-positive bacterial species. Three strains of this species, designated as M108T, M916-1/1, and M919-2/1, were non-haemolytic, H2S-positive, catalase-positive, bile- and NaCl-sensitive and required peptone for growth. Strains also were asaccharolytic, able to utilize sulfite, thiosulfate and elemental sulfur as electron acceptors, and produced acetic and butyric acids as metabolic end-products. Strain M108T is characterized by the prevalence of C14 : 0, C16 : 0 and C18 : 1ω9cis dimethyl acetal among the cellular fatty acids, and the presence of MK-10 menaquinone. The DNA G+C content was found to be 51 mol%. Phylogenetic analysis of partial 16S rRNA gene sequences of strains M108T, M916-1/1 and M919-2/1 placed these strains into the genus Peptococcus (family Peptococcaceae). On the basis of phenotypic and genotypic properties we conclude that these strains represent a novel bacterial species for which the name Peptococcus simiae sp. nov. is proposed. The type strain is M108T (=DSM 100347T=VKM B-2932T).
Collapse
Affiliation(s)
- Andrei N Shkoporov
- Department of Microbiology and Virology, Pirogov Russian National Research Medical University, Moscow 117997, Russia
| | - Boris A Efimov
- Department of Microbiology and Virology, Pirogov Russian National Research Medical University, Moscow 117997, Russia
| | - Ivanela Kondova
- Animal Science Department, Biomedical Primate Research Center, P.O. Box 3306, 2280 GH Rijswijk, The Netherlands
| | - Boudewijn Ouwerling
- Animal Science Department, Biomedical Primate Research Center, P.O. Box 3306, 2280 GH Rijswijk, The Netherlands
| | - Andrei V Chaplin
- Department of Microbiology and Virology, Pirogov Russian National Research Medical University, Moscow 117997, Russia
| | - Victoria A Shcherbakova
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino 142290, Russia
| | - Jan A M Langermans
- Animal Science Department, Biomedical Primate Research Center, P.O. Box 3306, 2280 GH Rijswijk, The Netherlands
| |
Collapse
|
35
|
|
36
|
Vuillemin A, Friese A, Alawi M, Henny C, Nomosatryo S, Wagner D, Crowe SA, Kallmeyer J. Geomicrobiological Features of Ferruginous Sediments from Lake Towuti, Indonesia. Front Microbiol 2016; 7:1007. [PMID: 27446046 PMCID: PMC4928248 DOI: 10.3389/fmicb.2016.01007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/13/2016] [Indexed: 11/23/2022] Open
Abstract
Lake Towuti is a tectonic basin, surrounded by ultramafic rocks. Lateritic soils form through weathering and deliver abundant iron (oxy)hydroxides but very little sulfate to the lake and its sediment. To characterize the sediment biogeochemistry, we collected cores at three sites with increasing water depth and decreasing bottom water oxygen concentrations. Microbial cell densities were highest at the shallow site-a feature we attribute to the availability of labile organic matter (OM) and the higher abundance of electron acceptors due to oxic bottom water conditions. At the two other sites, OM degradation and reduction processes below the oxycline led to partial electron acceptor depletion. Genetic information preserved in the sediment as extracellular DNA (eDNA) provided information on aerobic and anaerobic heterotrophs related to Nitrospirae, Chloroflexi, and Thermoplasmatales. These taxa apparently played a significant role in the degradation of sinking OM. However, eDNA concentrations rapidly decreased with core depth. Despite very low sulfate concentrations, sulfate-reducing bacteria were present and viable in sediments at all three sites, as confirmed by measurement of potential sulfate reduction rates. Microbial community fingerprinting supported the presence of taxa related to Deltaproteobacteria and Firmicutes with demonstrated capacity for iron and sulfate reduction. Concomitantly, sequences of Ruminococcaceae, Clostridiales, and Methanomicrobiales indicated potential for fermentative hydrogen and methane production. Such first insights into ferruginous sediments showed that microbial populations perform successive metabolisms related to sulfur, iron, and methane. In theory, iron reduction could reoxidize reduced sulfur compounds and desorb OM from iron minerals to allow remineralization to methane. Overall, we found that biogeochemical processes in the sediments can be linked to redox differences in the bottom waters of the three sites, like oxidant concentrations and the supply of labile OM. At the scale of the lacustrine record, our geomicrobiological study should provide a means to link the extant subsurface biosphere to past environments.
Collapse
Affiliation(s)
- Aurèle Vuillemin
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3 Geomicrobiology, Potsdam Germany
| | - André Friese
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3 Geomicrobiology, Potsdam Germany
| | - Mashal Alawi
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3 Geomicrobiology, Potsdam Germany
| | - Cynthia Henny
- Research Center for Limnology, Indonesian Institute of Sciences Cibinong, Indonesia
| | - Sulung Nomosatryo
- Research Center for Limnology, Indonesian Institute of Sciences Cibinong, Indonesia
| | - Dirk Wagner
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3 Geomicrobiology, Potsdam Germany
| | - Sean A Crowe
- Department of Microbiology and Immunology, University of British ColumbiaVancouver, BC, Canada; Department of Earth, Ocean, and Atmospheric Sciences, University of British ColumbiaVancouver, BC, Canada
| | - Jens Kallmeyer
- GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section 5.3 Geomicrobiology, Potsdam Germany
| |
Collapse
|
37
|
Shen Y, Jarboe L, Brown R, Wen Z. A thermochemical–biochemical hybrid processing of lignocellulosic biomass for producing fuels and chemicals. Biotechnol Adv 2015; 33:1799-813. [DOI: 10.1016/j.biotechadv.2015.10.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/16/2015] [Accepted: 10/16/2015] [Indexed: 12/28/2022]
|
38
|
Diender M, Stams AJM, Sousa DZ. Pathways and Bioenergetics of Anaerobic Carbon Monoxide Fermentation. Front Microbiol 2015; 6:1275. [PMID: 26635746 PMCID: PMC4652020 DOI: 10.3389/fmicb.2015.01275] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/31/2015] [Indexed: 11/29/2022] Open
Abstract
Carbon monoxide can act as a substrate for different modes of fermentative anaerobic metabolism. The trait of utilizing CO is spread among a diverse group of microorganisms, including members of bacteria as well as archaea. Over the last decade this metabolism has gained interest due to the potential of converting CO-rich gas, such as synthesis gas, into bio-based products. Three main types of fermentative CO metabolism can be distinguished: hydrogenogenesis, methanogenesis, and acetogenesis, generating hydrogen, methane and acetate, respectively. Here, we review the current knowledge on these three variants of microbial CO metabolism with an emphasis on the potential enzymatic routes and bio-energetics involved.
Collapse
Affiliation(s)
- Martijn Diender
- Laboratory of Microbiology, Wageningen University Wageningen, Netherlands
| | - Alfons J M Stams
- Laboratory of Microbiology, Wageningen University Wageningen, Netherlands ; Centre of Biological Engineering, University of Minho Braga, Portugal
| | - Diana Z Sousa
- Laboratory of Microbiology, Wageningen University Wageningen, Netherlands
| |
Collapse
|
39
|
Diaby N, Dold B, Rohrbach E, Holliger C, Rossi P. Temporal evolution of bacterial communities associated with the in situ wetland-based remediation of a marine shore porphyry copper tailings deposit. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 533:110-121. [PMID: 26151655 DOI: 10.1016/j.scitotenv.2015.06.076] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 06/04/2023]
Abstract
Mine tailings are a serious threat to the environment and public health. Remediation of these residues can be carried out effectively by the activation of specific microbial processes. This article presents detailed information about temporal changes in bacterial community composition during the remediation of a section of porphyry copper tailings deposited on the Bahía de Ite shoreline (Peru). An experimental remediation cell was flooded and transformed into a wetland in order to prevent oxidation processes, immobilizing metals. Initially, the top oxidation zone of the tailings deposit displayed a low pH (3.1) and high concentrations of metals, sulfate, and chloride, in a sandy grain size geological matrix. This habitat was dominated by sulfur- and iron-oxidizing bacteria, such as Leptospirillum spp., Acidithiobacillus spp., and Sulfobacillus spp., in a microbial community which structure resembled acid mine drainage environments. After wetland implementation, the cell was water-saturated, the acidity was consumed and metals dropped to a fraction of their initial respective concentrations. Bacterial communities analyzed by massive sequencing showed time-dependent changes both in composition and cell numbers. The final remediation stage was characterized by the highest bacterial diversity and evenness. Aside from classical sulfate reducers from the phyla δ-Proteobacteria and Firmicutes, community structure comprised taxa derived from very diverse habitats. The community was also characterized by an elevated proportion of rare phyla and unaffiliated sequences. Numerical ecology analysis confirmed that the temporal population evolution was driven by pH, redox, and K. Results of this study demonstrated the usefulness of a detailed follow-up of the remediation process, not only for the elucidation of the communities gradually switching from autotrophic, oxidizing to heterotrophic and reducing living conditions, but also for the long term management of the remediation wetlands.
Collapse
Affiliation(s)
- N Diaby
- University of Lausanne, Institute of Mineralogy and Geochemistry, Anthropole, Lausanne, Switzerland
| | - B Dold
- University of Lausanne, Institute of Mineralogy and Geochemistry, Anthropole, Lausanne, Switzerland
| | - E Rohrbach
- Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Laboratory for Environmental Biotechnology, Lausanne, Switzerland
| | - C Holliger
- Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Laboratory for Environmental Biotechnology, Lausanne, Switzerland
| | - P Rossi
- Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Central Environmental Laboratory, Lausanne, Switzerland.
| |
Collapse
|
40
|
Draft Genome Sequence of the Gram-Positive Thermophilic Iron Reducer Thermincola ferriacetica Strain Z-0001T. GENOME ANNOUNCEMENTS 2015; 3:3/5/e01072-15. [PMID: 26404602 PMCID: PMC4582578 DOI: 10.1128/genomea.01072-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A 3.19-Mbp draft genome of the Gram-positive thermophilic iron-reducing Firmicutes isolate from the Peptococcaceae family, Thermincola ferriacetica Z-0001, was assembled at ~100× coverage from 100-bp paired-end Illumina reads. The draft genome contains 3,274 predicted genes (3,187 protein coding genes) and putative multiheme c-type cytochromes.
Collapse
|
41
|
Abstract
Formation of heat-resistant endospores is a specific property of the members of the phylum Firmicutes (low-G+C Gram-positive bacteria). It is found in representatives of four different classes of Firmicutes, Bacilli, Clostridia, Erysipelotrichia, and Negativicutes, which all encode similar sets of core sporulation proteins. Each of these classes also includes non-spore-forming organisms that sometimes belong to the same genus or even species as their spore-forming relatives. This chapter reviews the diversity of the members of phylum Firmicutes, its current taxonomy, and the status of genome-sequencing projects for various subgroups within the phylum. It also discusses the evolution of the Firmicutes from their apparently spore-forming common ancestor and the independent loss of sporulation genes in several different lineages (staphylococci, streptococci, listeria, lactobacilli, ruminococci) in the course of their adaptation to the saprophytic lifestyle in a nutrient-rich environment. It argues that the systematics of Firmicutes is a rapidly developing area of research that benefits from the evolutionary approaches to the ever-increasing amount of genomic and phenotypic data and allows arranging these data into a common framework.
Collapse
|
42
|
Singh R, Dong H, Liu D, Zhao L, Marts AR, Farquhar E, Tierney DL, Almquist CB, Briggs BR. Reduction of hexavalent chromium by the thermophilic methanogen Methanothermobacter thermautotrophicus. GEOCHIMICA ET COSMOCHIMICA ACTA 2015; 148:442-456. [PMID: 26120143 PMCID: PMC4477973 DOI: 10.1016/j.gca.2014.10.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Despite the significant progress on iron reduction by thermophilic microorganisms, studies on their ability to reduce toxic metals are still limited, despite their common co-existence in high temperature environments (up to 70°C). In this study, Methanothermobacter thermautotrophicus, an obligate thermophilic methanogen, was used to reduce hexavalent chromium. Experiments were conducted in a growth medium with H2/CO2 as substrate with various Cr6+ concentrations (0.2, 0.4, 1, 3, and 5 mM) in the form of potassium dichromate (K2Cr2O7). Time-course measurements of aqueous Cr6+ concentrations with the 1, 5-diphenylcarbazide colorimetric method showed complete reduction of the 0.2 and 0.4 mM Cr6+ solutions by this methanogen. However, much lower reduction extents of 43.6%, 13.0%, and 3.7% were observed at higher Cr6+ concentrations of 1, 3 and 5 mM, respectively. These lower extents of bioreduction suggest a toxic effect of aqueous Cr6+ to cells at this concentration range. At these higher Cr6+ concentrations, methanogenesis was inhibited and cell growth was impaired as evidenced by decreased total cellular protein production and live/dead cell ratio. Likewise, Cr6+ bioreduction rates decreased with increased initial concentrations of Cr6+ from 13.3 to1.9 µM h-1. X-ray absorption near-edge structure (XANES) spectroscopy revealed a progressive reduction of soluble Cr6+ to insoluble Cr3+ precipitates, which was confirmed as amorphous chromium hydroxide by X-ray diffraction and selected area electron diffraction pattern. However, a small fraction of reduced Cr occurred as aqueous Cr3+. Scanning and transmission electron microscope observations of M. thermautotrophicus cells after Cr6+ exposure suggest both extra- and intracellular chromium reduction mechanisms. Results of this study demonstrate the ability of M. thermautotrophicus cells to reduce toxic Cr6+ to less toxic Cr3+ and its potential application in metal bioremediation, especially at high temperature subsurface radioactive waste disposal sites, where the temperature may reach ∼70°C.
Collapse
Affiliation(s)
- Rajesh Singh
- Department of Geology and Environmental Earth Science, Miami University, Oxford, OH-45056
| | - Hailiang Dong
- Department of Geology and Environmental Earth Science, Miami University, Oxford, OH-45056
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China
| | - Deng Liu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China
| | - Linduo Zhao
- Department of Geology and Environmental Earth Science, Miami University, Oxford, OH-45056
| | - Amy R. Marts
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH-45056
| | - Erik Farquhar
- Case Western Reserve University Center for Synchrotron Biosciences, National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973
| | - David L. Tierney
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH-45056
| | | | - Brandon R. Briggs
- Department of Geology and Environmental Earth Science, Miami University, Oxford, OH-45056
| |
Collapse
|
43
|
Rittmann SKM, Lee HS, Lim JK, Kim TW, Lee JH, Kang SG. One-carbon substrate-based biohydrogen production: Microbes, mechanism, and productivity. Biotechnol Adv 2015; 33:165-177. [DOI: 10.1016/j.biotechadv.2014.11.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 10/10/2014] [Accepted: 11/11/2014] [Indexed: 11/28/2022]
|
44
|
Martinez CM, Alvarez LH, Celis LB, Cervantes FJ. Humus-reducing microorganisms and their valuable contribution in environmental processes. Appl Microbiol Biotechnol 2013; 97:10293-308. [PMID: 24220793 DOI: 10.1007/s00253-013-5350-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/17/2013] [Accepted: 10/19/2013] [Indexed: 02/08/2023]
Abstract
Humus constitutes a very abundant class of organic compounds that are chemically heterogeneous and widely distributed in terrestrial and aquatic environments. Evidence accumulated during the last decades indicating that humic substances play relevant roles on the transport, fate, and redox conversion of organic and inorganic compounds both in chemically and microbially driven reactions. The present review underlines the contribution of humus-reducing microorganisms in relevant environmental processes such as biodegradation of recalcitrant pollutants and mitigation of greenhouse gases emission in anoxic ecosystems, redox conversion of industrial contaminants in anaerobic wastewater treatment systems, and on the microbial production of nanocatalysts and alternative energy sources.
Collapse
Affiliation(s)
- Claudia M Martinez
- División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), Camino a la Presa San José 2055, Col. Lomas 4a Sección, San Luis Potosí, SLP, 78216, Mexico
| | | | | | | |
Collapse
|
45
|
Parameswaran P, Bry T, Popat SC, Lusk BG, Rittmann BE, Torres CI. Kinetic, electrochemical, and microscopic characterization of the thermophilic, anode-respiring bacterium Thermincola ferriacetica. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:4934-4940. [PMID: 23544360 DOI: 10.1021/es400321c] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Thermincola ferriacetica is a recently isolated thermophilic, dissimilatory Fe(III)-reducing, Gram-positive bacterium with capability to generate electrical current via anode respiration. Our goals were to determine the maximum rates of anode respiration by T. ferriacetica and to perform a detailed microscopic and electrochemical characterization of the biofilm anode. T. ferriacetica DSM 14005 was grown at 60 °C on graphite-rod anodes poised at -0.06 V (vs) SHE in duplicate microbial electrolysis cells (MECs). The cultures grew rapidly until they achieved a sustained current density of 7-8 A m(-2) with only 10 mM bicarbonate buffer and an average Coulombic Efficiency (CE) of 93%. Cyclic voltammetry performed at maximum current density revealed a Nernst-Monod response with a half saturation potential (EKA) of -0.127 V (vs) SHE. Confocal microscopy images revealed a thick layer of actively respiring cells of T. ferriacetica (~38 μm), which is the first documentation for a gram positive anode respiring bacterium (ARB). Scanning electron microscopy showed a well-developed biofilm with a very dense network of extracellular appendages similar to Geobacter biofilms. The high current densities, a thick biofilm (~38 μm) with multiple layers of active cells, and Nernst-Monod behavior support extracellular electron transfer (EET) through a solid conductive matrix - the first such observation for Gram-positive bacteria. Operating with a controlled anode potential enabled us to grow T. ferriacetica that can use a solid conductive matrix resulting in high current densities that are promising for MXC applications.
Collapse
Affiliation(s)
- Prathap Parameswaran
- Swette Center for Environmental Biotechnology, The Biodesign Institute at Arizona State University, P.O. Box 875701, Tempe, Arizona 85287, USA.
| | | | | | | | | | | |
Collapse
|
46
|
Fu Q, Kobayashi H, Kawaguchi H, Vilcaez J, Wakayama T, Maeda H, Sato K. Electrochemical and phylogenetic analyses of current-generating microorganisms in a thermophilic microbial fuel cell. J Biosci Bioeng 2013; 115:268-71. [DOI: 10.1016/j.jbiosc.2012.10.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 09/29/2012] [Accepted: 10/09/2012] [Indexed: 11/25/2022]
|
47
|
Galperin MY, Mekhedov SL, Puigbo P, Smirnov S, Wolf YI, Rigden DJ. Genomic determinants of sporulation in Bacilli and Clostridia: towards the minimal set of sporulation-specific genes. Environ Microbiol 2012; 14:2870-90. [PMID: 22882546 PMCID: PMC3533761 DOI: 10.1111/j.1462-2920.2012.02841.x] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Three classes of low-G+C Gram-positive bacteria (Firmicutes), Bacilli, Clostridia and Negativicutes, include numerous members that are capable of producing heat-resistant endospores. Spore-forming firmicutes include many environmentally important organisms, such as insect pathogens and cellulose-degrading industrial strains, as well as human pathogens responsible for such diseases as anthrax, botulism, gas gangrene and tetanus. In the best-studied model organism Bacillus subtilis, sporulation involves over 500 genes, many of which are conserved among other bacilli and clostridia. This work aimed to define the genomic requirements for sporulation through an analysis of the presence of sporulation genes in various firmicutes, including those with smaller genomes than B. subtilis. Cultivable spore-formers were found to have genomes larger than 2300 kb and encompass over 2150 protein-coding genes of which 60 are orthologues of genes that are apparently essential for sporulation in B. subtilis. Clostridial spore-formers lack, among others, spoIIB, sda, spoVID and safA genes and have non-orthologous displacements of spoIIQ and spoIVFA, suggesting substantial differences between bacilli and clostridia in the engulfment and spore coat formation steps. Many B. subtilis sporulation genes, particularly those encoding small acid-soluble spore proteins and spore coat proteins, were found only in the family Bacillaceae, or even in a subset of Bacillus spp. Phylogenetic profiles of sporulation genes, compiled in this work, confirm the presence of a common sporulation gene core, but also illuminate the diversity of the sporulation processes within various lineages. These profiles should help further experimental studies of uncharacterized widespread sporulation genes, which would ultimately allow delineation of the minimal set(s) of sporulation-specific genes in Bacilli and Clostridia.
Collapse
Affiliation(s)
- Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
| | | | | | | | | | | |
Collapse
|
48
|
Kellermann C, Selesi D, Lee N, Hügler M, Esperschütz J, Hartmann A, Griebler C. Microbial CO2 fixation potential in a tar-oil-contaminated porous aquifer. FEMS Microbiol Ecol 2012; 81:172-87. [DOI: 10.1111/j.1574-6941.2012.01359.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 03/05/2012] [Accepted: 03/06/2012] [Indexed: 02/04/2023] Open
Affiliation(s)
- Claudia Kellermann
- Institute of Groundwater Ecology; Helmholtz Zentrum München; German Research Center for Environmental Health (GmbH); Neuherberg; Germany
| | - Draženka Selesi
- Institute of Groundwater Ecology; Helmholtz Zentrum München; German Research Center for Environmental Health (GmbH); Neuherberg; Germany
| | - Natuschka Lee
- Lehrstuhl für Mikrobiologie; Technische Universität München; Munich; Germany
| | - Michael Hügler
- DVGW - Technologiezentrum Wasser (TZW); Karlsruhe; Germany
| | - Jürgen Esperschütz
- Research Unit Environmental Genomics; Helmholtz Zentrum München; German Research Center for Environmental Health (GmbH); Neuherberg; Germany
| | - Anton Hartmann
- Research Unit Microbe-Plant Interactions; Helmholtz Zentrum München; German Research Center for Environmental Health (GmbH); Neuherberg; Germany
| | - Christian Griebler
- Institute of Groundwater Ecology; Helmholtz Zentrum München; German Research Center for Environmental Health (GmbH); Neuherberg; Germany
| |
Collapse
|
49
|
Surface multiheme c-type cytochromes from Thermincola potens and implications for respiratory metal reduction by Gram-positive bacteria. Proc Natl Acad Sci U S A 2012; 109:1702-7. [PMID: 22307634 DOI: 10.1073/pnas.1112905109] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Almost nothing is known about the mechanisms of dissimilatory metal reduction by Gram-positive bacteria, although they may be the dominant species in some environments. Thermincola potens strain JR was isolated from the anode of a microbial fuel cell inoculated with anaerobic digester sludge and operated at 55 °C. Preliminary characterization revealed that T. potens coupled acetate oxidation to the reduction of hydrous ferric oxides (HFO) or anthraquinone-2,6-disulfonate (AQDS), an analog of the redox active components of humic substances. The genome of T. potens was recently sequenced, and the abundance of multiheme c-type cytochromes (MHCs) is unusual for a Gram-positive bacterium. We present evidence from trypsin-shaving LC-MS/MS experiments and surface-enhanced Raman spectroscopy (SERS) that indicates the expression of a number of MHCs during T. potens growth on either HFO or AQDS, and that several MHCs are localized to the cell wall or cell surface. Furthermore, one of the MHCs can be extracted from cells with low pH or denaturants, suggesting a loose association with the cell wall or cell surface. Electron microscopy does not reveal an S-layer, and the precipitation of silver metal on the cell surface is inhibited by cyanide, supporting the involvement of surface-localized redox-active heme proteins in dissimilatory metal reduction. These results provide unique direct evidence for cell wall-associated cytochromes and support MHC involvement in conducting electrons across the cell envelope of a Gram-positive bacterium.
Collapse
|
50
|
Evidence for direct electron transfer by a gram-positive bacterium isolated from a microbial fuel cell. Appl Environ Microbiol 2011; 77:7633-9. [PMID: 21908627 DOI: 10.1128/aem.05365-11] [Citation(s) in RCA: 170] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite their importance in iron redox cycles and bioenergy production, the underlying physiological, genetic, and biochemical mechanisms of extracellular electron transfer by Gram-positive bacteria remain insufficiently understood. In this work, we investigated respiration by Thermincola potens strain JR, a Gram-positive isolate obtained from the anode surface of a microbial fuel cell, using insoluble electron acceptors. We found no evidence that soluble redox-active components were secreted into the surrounding medium on the basis of physiological experiments and cyclic voltammetry measurements. Confocal microscopy revealed highly stratified biofilms in which cells contacting the electrode surface were disproportionately viable relative to the rest of the biofilm. Furthermore, there was no correlation between biofilm thickness and power production, suggesting that cells in contact with the electrode were primarily responsible for current generation. These data, along with cryo-electron microscopy experiments, support contact-dependent electron transfer by T. potens strain JR from the cell membrane across the 37-nm cell envelope to the cell surface. Furthermore, we present physiological and genomic evidence that c-type cytochromes play a role in charge transfer across the Gram-positive bacterial cell envelope during metal reduction.
Collapse
|