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Teng Z, Zhang N, Zhang L, Zhang L, Liu S, Fu T, Wang Q, Gao T. Integrated Multi-Omics Reveals New Ruminal Microbial Features Associated with Peanut Vine Efficiency in Dairy Cattle. Life (Basel) 2024; 14:802. [PMID: 39063557 PMCID: PMC11277927 DOI: 10.3390/life14070802] [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: 04/20/2024] [Revised: 06/17/2024] [Accepted: 06/22/2024] [Indexed: 07/28/2024] Open
Abstract
The aim of this study was to improve the utilization of peanut vines as forage material for ruminants by investigating the degradation pattern of peanut vines in the dairy cow rumen. Samples of peanut vine incubated in cow rumens were collected at various time points. Bacterial diversity was investigated by scanning electron microscopy (SEM) and 16S rRNA gene sequencing. Carbohydrate-active enzymes (CAZymes) were analyzed by metagenomics. The peanut vines degraded rapidly from 2 to 24 h, before slowing from 24 to 72 h. SEM images confirmed dynamic peanut vine colonization. Firmicutes and Bacteroidetes were the two most dominant bacterial phyla throughout. Principal coordinates analysis indicated significant microbial composition changes at 6 and 24 h. This may be because, in the early stage, soluble carbohydrates that are easily degradable were degraded, while in the later stage, fibrous substances that are difficult to degrade were mainly degraded. Glycoside hydrolases (GHs) were the most abundant CAZymes, with peak relative abundance at 6 h (56.7 trans per million, TPM), and reducing at 24 (55.9 TPM) and 72 h (55.3 TPM). Spearman correlation analysis showed that Alistipes_sp._CAG:435, Alistipes_sp._CAG:514, Bacteroides_sp._CAG:1060, Bacteroides_sp._CAG:545, Bacteroides_sp._CAG:709, Bacteroides_sp._CAG:770, bacterium_F082, bacterium_F083, GH29, GH78, and GH92 were important for plant fiber degradation. These findings provide fundamental knowledge about forage degradation in the cow rumen, and will be important for the targeted improvement of ruminant plant biomass utilization efficiency.
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Affiliation(s)
- Zhanwei Teng
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, China; (Z.T.)
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
- Postdoctoral Research Base, Henan Institute of Science and Technology, Xinxiang 453003, China
| | - Ningning Zhang
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, China; (Z.T.)
| | - Lijie Zhang
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
| | - Liyang Zhang
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
| | - Shenhe Liu
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
| | - Tong Fu
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
| | - Qinghua Wang
- College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, China; (Z.T.)
| | - Tengyun Gao
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, China
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2
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Suzuki S, Ishii S, Chadwick GL, Tanaka Y, Kouzuma A, Watanabe K, Inagaki F, Albertsen M, Nielsen PH, Nealson KH. A non-methanogenic archaeon within the order Methanocellales. Nat Commun 2024; 15:4858. [PMID: 38871712 DOI: 10.1038/s41467-024-48185-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 04/22/2024] [Indexed: 06/15/2024] Open
Abstract
Serpentinization, a geochemical process found on modern and ancient Earth, provides an ultra-reducing environment that can support microbial methanogenesis and acetogenesis. Several groups of archaea, such as the order Methanocellales, are characterized by their ability to produce methane. Here, we generate metagenomic sequences from serpentinized springs in The Cedars, California, and construct a circularized metagenome-assembled genome of a Methanocellales archaeon, termed Met12, that lacks essential methanogenesis genes. The genome includes genes for an acetyl-CoA pathway, but lacks genes encoding methanogenesis enzymes such as methyl-coenzyme M reductase, heterodisulfide reductases and hydrogenases. In situ transcriptomic analyses reveal high expression of a multi-heme c-type cytochrome, and heterologous expression of this protein in a model bacterium demonstrates that it is capable of accepting electrons. Our results suggest that Met12, within the order Methanocellales, is not a methanogen but a CO2-reducing, electron-fueled acetogen without electron bifurcation.
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Affiliation(s)
- Shino Suzuki
- Geobiology and Astrobiology Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, Japan.
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa, Japan.
- School of Physical Sciences, SOKENDAI (Graduate University for Advanced Studies), Sagamihara, Kanagawa, Japan.
- Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), Japan Agency for Marine and Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan.
| | - Shun'ichi Ishii
- Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), Japan Agency for Marine and Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan.
| | - Grayson L Chadwick
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Yugo Tanaka
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Atsushi Kouzuma
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Kazuya Watanabe
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Fumio Inagaki
- Advanced Institute for Marine Ecosystem Change (WPI-AIMEC), JAMSTEC, Yokohama, Kanagawa, Japan
- Department of Earth Science, Graduate School of Science, Tohoku University, Sendai, Miyagi, Japan
| | - Mads Albertsen
- Center for Microbial Communities, Aalborg University, Aalborg, Denmark
| | - Per H Nielsen
- Center for Microbial Communities, Aalborg University, Aalborg, Denmark
| | - Kenneth H Nealson
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA
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Cong S, Xu Y, Lu Y. Growth Coordination Between Butyrate-Oxidizing Syntrophs and Hydrogenotrophic Methanogens. Front Microbiol 2021; 12:742531. [PMID: 34603271 PMCID: PMC8481629 DOI: 10.3389/fmicb.2021.742531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 08/18/2021] [Indexed: 11/13/2022] Open
Abstract
Syntrophy is a thermodynamically required mutualistic cooperation between fatty acid-oxidizing bacteria and methanogens that plays the important role in organic decomposition and methanogenesis in anoxic environments. In this study, three experiments were conducted to evaluate the cell-to-cell interaction in a thermophilic coculture consisting of Syntrophothermus lipocalidus and Methanocella conradii and a mesophilic coculture consisting of Syntrophomonas wolfei and Methanococcus maripaludis. First, syntrophs and methanogens were inoculated at different initial cell ratios to evaluate the growth synchronization. The quantitative PCR analysis revealed that the organism with a lower relative abundance at the beginning always grew faster, and the cell ratio converged over time to relative constant values in both the thermophilic and mesophilic cocultures. Next, intermittent ultrasound and constant shaking treatments were used to evaluate the influence of physical disturbance on microbial aggregation in the mesophilic coculture. The fluorescence in situ hybridization and scanning electron microscopy revealed that the tendency of syntrophic aggregation was not affected by the physical disturbances, although the activity was slightly depressed. Syntrophomonas dominated in the initial microbial aggregates, which, however, did not grow until Methanococcus was attached and increased to a significant extent, indicating the local growth synchronization during the formation and maturation of syntrophic aggregates. Last, microfluidic experiments revealed that whether or not Syntrophomonas or Methanococcus was loaded first, the second organism preferred moving to the place where the first organism was located, suggesting the cell-to-cell attraction between Syntrophomonas and Methanococcus. Collectively, our study demonstrated the growth synchronization and cell-to-cell attraction between the butyrate-oxidizing bacteria and methanogens for optimizing the syntrophic cooperation.
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Affiliation(s)
- Shuqi Cong
- College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Yiqin Xu
- College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Yahai Lu
- College of Urban and Environmental Sciences, Peking University, Beijing, China
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4
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Kruse S, Türkowsky D, Birkigt J, Matturro B, Franke S, Jehmlich N, von Bergen M, Westermann M, Rossetti S, Nijenhuis I, Adrian L, Diekert G, Goris T. Interspecies metabolite transfer and aggregate formation in a co-culture of Dehalococcoides and Sulfurospirillum dehalogenating tetrachloroethene to ethene. THE ISME JOURNAL 2021; 15:1794-1809. [PMID: 33479489 PMCID: PMC8163811 DOI: 10.1038/s41396-020-00887-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 12/04/2020] [Accepted: 12/16/2020] [Indexed: 01/30/2023]
Abstract
Microbial communities involving dehalogenating bacteria assist in bioremediation of areas contaminated with halocarbons. To understand molecular interactions between dehalogenating bacteria, we co-cultured Sulfurospirillum multivorans, dechlorinating tetrachloroethene (PCE) to cis-1,2-dichloroethene (cDCE), and Dehalococcoides mccartyi strains BTF08 or 195, dehalogenating PCE to ethene. The co-cultures were cultivated with lactate as electron donor. In co-cultures, the bacterial cells formed aggregates and D. mccartyi established an unusual, barrel-like morphology. An extracellular matrix surrounding bacterial cells in the aggregates enhanced cell-to-cell contact. PCE was dehalogenated to ethene at least three times faster in the co-culture. The dehalogenation was carried out via PceA of S. multivorans, and PteA (a recently described PCE dehalogenase) and VcrA of D. mccartyi BTF08, as supported by protein abundance. The co-culture was not dependent on exogenous hydrogen and acetate, suggesting a syntrophic relationship in which the obligate hydrogen consumer D. mccartyi consumes hydrogen and acetate produced by S. multivorans. The cobamide cofactor of the reductive dehalogenase-mandatory for D. mccartyi-was also produced by S. multivorans. D. mccartyi strain 195 dechlorinated cDCE in the presence of norpseudo-B12 produced by S. multivorans, but D. mccartyi strain BTF08 depended on an exogenous lower cobamide ligand. This observation is important for bioremediation, since cofactor supply in the environment might be a limiting factor for PCE dehalogenation to ethene, described for D. mccartyi exclusively. The findings from this co-culture give new insights into aggregate formation and the physiology of D. mccartyi within a bacterial community.
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Affiliation(s)
- Stefan Kruse
- grid.9613.d0000 0001 1939 2794Department of Applied and Ecological Microbiology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Dominique Türkowsky
- grid.7492.80000 0004 0492 3830Department Molecular Systems Biology, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
| | - Jan Birkigt
- grid.7492.80000 0004 0492 3830Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
| | - Bruna Matturro
- grid.435629.f0000 0004 1755 3971Water Research Institute, IRSA-CNR, Monterotondo, Rome, Italy
| | - Steffi Franke
- grid.7492.80000 0004 0492 3830Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany ,Present Address: Eurofins Institute Dr. Appelt Leipzig, Leipzig, Germany
| | - Nico Jehmlich
- grid.7492.80000 0004 0492 3830Department Molecular Systems Biology, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
| | - Martin von Bergen
- grid.7492.80000 0004 0492 3830Department Molecular Systems Biology, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany ,grid.9647.c0000 0004 7669 9786Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Leipzig, Germany
| | - Martin Westermann
- grid.275559.90000 0000 8517 6224Center for Electron Microscopy of the University Hospital Jena, Jena, Germany
| | - Simona Rossetti
- grid.435629.f0000 0004 1755 3971Water Research Institute, IRSA-CNR, Monterotondo, Rome, Italy
| | - Ivonne Nijenhuis
- grid.7492.80000 0004 0492 3830Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
| | - Lorenz Adrian
- grid.6734.60000 0001 2292 8254Chair of Geobiotechnology, Technische Universität Berlin, Berlin, Germany ,grid.7492.80000 0004 0492 3830Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Gabriele Diekert
- grid.9613.d0000 0001 1939 2794Department of Applied and Ecological Microbiology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Tobias Goris
- grid.9613.d0000 0001 1939 2794Department of Applied and Ecological Microbiology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany ,grid.418213.d0000 0004 0390 0098Present Address: German Institute of Human Nutrition, Department Molecular Toxicology, Research Group Intestinal Microbiology, Potsdam-Rehbrücke, Nuthetal, Germany
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5
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Afonso AC, Gomes IB, Saavedra MJ, Giaouris E, Simões LC, Simões M. Bacterial coaggregation in aquatic systems. WATER RESEARCH 2021; 196:117037. [PMID: 33751976 DOI: 10.1016/j.watres.2021.117037] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 03/07/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
The establishment of a sessile community is believed to occur in a sequence of steps where genetically distinct bacteria can become attached to partner cells via specific molecules, in a process known as coaggregation. The presence of bacteria with the ability to autoaggregate and coaggregate has been described for diverse aquatic systems, particularly freshwater, drinking water, wastewater, and marine water. In these aquatic systems, coaggregation already demonstrated a role in the development of complex multispecies sessile communities, including biofilms. While specific molecular aspects on coaggregation in aquatic systems remain to be understood, clear evidence exist on the impact of this mechanism in multispecies biofilm resilience and homeostasis. The identification of bridging bacteria among coaggregating consortia has potential to improve the performance of wastewater treatment plants and/or to contribute for the development of strategies to control undesirable biofilms. This study provides a comprehensive analysis on the occurrence and role of bacterial coaggregation in diverse aquatic systems. The potential of this mechanism in water-related biotechnology is further described, with particular emphasis on the role of bridging bacteria.
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Affiliation(s)
- Ana C Afonso
- LEPABE, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal
| | - Inês B Gomes
- LEPABE, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal
| | - Maria José Saavedra
- CITAB, Centre for the Research and Technology for Agro-Environment and Biological Sciences, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal
| | - Efstathios Giaouris
- Department of Food Science and Nutrition, School of the Environment, University of the Aegean, Ierou Lochou 10 & Makrygianni, Myrina 81400, Lemnos, Greece
| | - Lúcia C Simões
- CEB, Centre of Biological Engineering, University of Minho, Campus de Gualtar, Braga, Portugal
| | - Manuel Simões
- LEPABE, Faculty of Engineering, Department of Chemical Engineering, University of Porto, Porto, Portugal.
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6
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The significance of microbial community functions and symbiosis in enhancing methane production during anaerobic digestion: a review. Symbiosis 2020. [DOI: 10.1007/s13199-020-00734-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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7
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Gupta D, Guzman MS, Bose A. Extracellular electron uptake by autotrophic microbes: physiological, ecological, and evolutionary implications. ACTA ACUST UNITED AC 2020; 47:863-876. [DOI: 10.1007/s10295-020-02309-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/07/2020] [Indexed: 02/05/2023]
Abstract
Abstract
Microbes exchange electrons with their extracellular environment via direct or indirect means. This exchange is bidirectional and supports essential microbial oxidation–reduction processes, such as respiration and photosynthesis. The microbial capacity to use electrons from insoluble electron donors, such as redox-active minerals, poised electrodes, or even other microbial cells is called extracellular electron uptake (EEU). Autotrophs with this capability can thrive in nutrient and soluble electron donor-deficient environments. As primary producers, autotrophic microbes capable of EEU greatly impact microbial ecology and play important roles in matter and energy flow in the biosphere. In this review, we discuss EEU-driven autotrophic metabolisms, their mechanism and physiology, and highlight their ecological, evolutionary, and biotechnological implications.
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Affiliation(s)
- Dinesh Gupta
- grid.4367.6 0000 0001 2355 7002 Department of Biology Washington University in St. Louis One Brookings Drive 63130 St. Louis MO USA
| | - Michael S Guzman
- grid.250008.f 0000 0001 2160 9702 Biosciences and Biotechnology Division Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory Livermore CA USA
| | - Arpita Bose
- grid.4367.6 0000 0001 2355 7002 Department of Biology Washington University in St. Louis One Brookings Drive 63130 St. Louis MO USA
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8
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Bi Y, Marcus AK, Robert H, Krajmalnik-Brown R, Rittmann BE, Westerhoff P, Ropers MH, Mercier-Bonin M. The complex puzzle of dietary silver nanoparticles, mucus and microbiota in the gut. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2020; 23:69-89. [PMID: 31920169 DOI: 10.1080/10937404.2019.1710914] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Hundreds of consumer and commercial products containing silver nanoparticles (AgNPs) are currently used in food, personal-care products, pharmaceutical, and many other applications. Human exposure to AgNPs includes oral intake, inhalation, and dermal contact. The aim of this review was to focus on oral intake, intentional and incidental of AgNPs where well-known antimicrobial characteristics that might affect the microbiome and mucus in the gastrointestinal tract (GIT). This critical review summarizes what is known regarding the impacts of AgNPs on gut homeostasis. It is fundamental to understand the forms of AgNPs and their physicochemical characterization before and during digestion. For example, lab-synthesized AgNPs differ from "real" ingestable AgNPs used as food additives and dietary supplements. Similarly, the gut environment alters the chemical and physical state of Ag that is ingested as AgNPs. Emerging research on in vitro and in vivo rodent and human indicated complex multi-directional relationships among AgNPs, the intestinal microbiota, and the epithelial mucus. It may be necessary to go beyond today's descriptive approach to a modeling-based ecosystem approach that might quantitatively integrate spatio-temporal interactions among microbial groups, host factors (e.g., mucus), and environmental factors, including lifestyle-based stressors. It is suggested that future research (1) utilize more representative AgNPs, focus on microbe/mucus interactions, (2) assess the effects of environmental stressors for longer and longitudinal conditions, and (3) be integrated using quantitative modeling.
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Affiliation(s)
- Yuqiang Bi
- Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, Arizona State University, Tempe, AZ, USA
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA
| | - Andrew K Marcus
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, USA
| | - Hervé Robert
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Rosa Krajmalnik-Brown
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, USA
| | - Bruce E Rittmann
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University, Tempe, AZ, USA
| | - Paul Westerhoff
- Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment, Arizona State University, Tempe, AZ, USA
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, USA
| | | | - Muriel Mercier-Bonin
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
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9
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Wang C, Wang C, Jin L, Lu D, Chen H, Zhu W, Xu X, Zhu L. Response of syntrophic aggregates to the magnetite loss in continuous anaerobic bioreactor. WATER RESEARCH 2019; 164:114925. [PMID: 31382155 DOI: 10.1016/j.watres.2019.114925] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 07/25/2019] [Accepted: 07/27/2019] [Indexed: 06/10/2023]
Abstract
Increasing studies indicate that magnetite addition could accelerate the methanogenesis via enhancing direct interspecies electron transfer (DIET)-based anaerobic syntrophy. However, magnetite is found to run off in continuous bioreactor, and the effect of magnetite loss on syntrophic aggregates is still underreported. In this study, two EGSB reactors (RM with magnetite-enhanced sludge, and RB as a control) were operated to investigate the magnetite behavior in continuous bioreactor and the corresponding response of syntrophic aggregates. Results showed that magnetite in RM was washed out gradually in form of iron ions, and a slightly acidic niche was supposed to be the major cause. Nevertheless, candidate DIET partners like Geobacter and Methanothrix along with syntrophic volatile fatty acids (VFAs)-degrading microbes were enriched in RM. In addition, the improved redox activity of extracellular polymeric substance (EPS), higher sludge conductivity and electron transport activity suggested that the DIET ability of sludge in RM was still enhanced, which favors the syntrophic metabolism of VFAs. Interestingly, syntrophic partners were loosely combined under the condition of high organic loading rate (OLR) in the presence of magnetite, but with gradual loss of magnetite, dense and active anaerobic granular sludge (AGS) was formed in RM. This study provided a comprehensive understanding of magnetite behavior in continuous bioreactor and the response of syntrophic aggregates. The robust DIET-based syntrophy after magnetite adding could favor the high-efficient anaerobic wastewater treatment and resource recovery in the future, and further investigations on magnetite resupply and the mechanism of magnetite enriching candidate DIET partners are recommended.
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Affiliation(s)
- Caiqin Wang
- Institute of Environment Pollution Control and Treatment, Zhejiang University, Hangzhou, 310058, China
| | - Chen Wang
- Institute of Environment Pollution Control and Treatment, Zhejiang University, Hangzhou, 310058, China
| | - Luonan Jin
- Hangzhou Urban & Rural Construction Design Institute Co., LTD, Hangzhou, 310004, China
| | - Donghui Lu
- Institute of Environment Pollution Control and Treatment, Zhejiang University, Hangzhou, 310058, China
| | - Hui Chen
- Institute of Environment Pollution Control and Treatment, Zhejiang University, Hangzhou, 310058, China
| | - Weitang Zhu
- Environmental Protection Bureau of Changxing County, Huzhou, 313100, China
| | - Xiangyang Xu
- Institute of Environment Pollution Control and Treatment, Zhejiang University, Hangzhou, 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310058, China; Zhejiang Provincial Engineering Laboratory of Water Pollution Control, 388 Yuhangtang Road, Hangzhou, 310058, China
| | - Liang Zhu
- Institute of Environment Pollution Control and Treatment, Zhejiang University, Hangzhou, 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310058, China; Zhejiang Provincial Engineering Laboratory of Water Pollution Control, 388 Yuhangtang Road, Hangzhou, 310058, China.
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10
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Kosaka T, Goda M, Inoue M, Yakushi T, Yamada M. Flagellum-mediated motility in Pelotomaculum thermopropionicum SI. Biosci Biotechnol Biochem 2019; 83:1362-1371. [PMID: 30919743 DOI: 10.1080/09168451.2019.1597618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The basic functions of a propionate-oxidizing bacterium Pelotomaculum thermopropionicum flagellum, such as motility and chemotaxis, have not been studied. To investigate its motility, we compared with that of Syntrophobacter fumaroxidans, an aflagellar propionate-oxidizing bacterium, in soft agar medium. P. thermopropionicum cells spread, while S. fumaroxidans cells moved downward slightly, indicating flagellum-dependent motility in P. thermopropionicum SI. The motility of P. thermopropionicum was inhibited by the addition of carbonyl cyanide m-chlorophenyl hydrazone, a proton uncoupler, which is consistent with the fact that stator protein, MotB of P. thermopropionicum, shared sequence homology with proton-type stators. In addition, 5-N-ethyl-N-isopropyl amiloride, an Na+ channel blocker, showed no inhibitory effect on the motility. Furthermore, motAB of P. thermopropionicum complemented the defective swimming ability of Escherichia coli ∆motAB. These results suggest that the motility of P. thermopropionicum SI depends on the proton-type flagellar motor.
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Affiliation(s)
- Tomoyuki Kosaka
- a Department of Biological Chemistry, College of Agriculture, Graduate school of Science and Technology for Innovation , Yamaguchi University , Yamaguchi , Japan.,b Research Center for Thermotolerant Microbial Resources , Yamaguchi University , Yamaguchi , Japan
| | - Mutsumi Goda
- a Department of Biological Chemistry, College of Agriculture, Graduate school of Science and Technology for Innovation , Yamaguchi University , Yamaguchi , Japan
| | - Manami Inoue
- a Department of Biological Chemistry, College of Agriculture, Graduate school of Science and Technology for Innovation , Yamaguchi University , Yamaguchi , Japan
| | - Toshiharu Yakushi
- a Department of Biological Chemistry, College of Agriculture, Graduate school of Science and Technology for Innovation , Yamaguchi University , Yamaguchi , Japan.,b Research Center for Thermotolerant Microbial Resources , Yamaguchi University , Yamaguchi , Japan
| | - Mamoru Yamada
- a Department of Biological Chemistry, College of Agriculture, Graduate school of Science and Technology for Innovation , Yamaguchi University , Yamaguchi , Japan.,b Research Center for Thermotolerant Microbial Resources , Yamaguchi University , Yamaguchi , Japan
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11
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Liu P, Lu Y. Concerted Metabolic Shifts Give New Insights Into the Syntrophic Mechanism Between Propionate-Fermenting Pelotomaculum thermopropionicum and Hydrogenotrophic Methanocella conradii. Front Microbiol 2018; 9:1551. [PMID: 30038609 PMCID: PMC6046458 DOI: 10.3389/fmicb.2018.01551] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 06/21/2018] [Indexed: 11/13/2022] Open
Abstract
Microbial syntrophy is a thermodynamically-based cooperation between microbial partners that share the small amounts of free energy for anaerobic growth. To gain insights into the mechanism by which syntrophic microorganisms coordinate their metabolism, we constructed cocultures of propionate-oxidizing Pelotomaculum thermopropionicum and hydrogenotrophic Methanocella conradii and compared them to monocultures. Transcriptome analysis was performed on these cultures using strand-specific mRNA sequencing (RNA-Seq). The results showed that in coculture both P. thermopropionicum and M. conradii significantly upregulated the expression of genes involved in catabolism but downregulated those for anabolic biosynthesis. Specifically, genes coding for the methylmalonyl-CoA pathway in P. thermopropionicum and key genes for methanogenesis in M. conradii were substantially upregulated in coculture compared to monoculture. The putative flavin-based electron bifurcation/confurcation systems in both organisms were also upregulated in coculture. Formate dehydrogenase encoding genes in both organisms were markedly upregulated, indicating that formate was produced and utilized by P. thermopropionicum and M. conradii, respectively. The inhibition of syntrophic activity by formate and 2-bromoethanesulphonate (2-BES) but not H2/CO2 also suggested that formate production was used by P. thermopropionicum for the recycling of intracellular redox mediators. Finally, flagellum-induced signal transduction and amino acids exchange was upregulated for syntrophic interactions. Together, our study suggests that syntrophic organisms employ multiple strategies including global metabolic shift, utilization of electron bifurcation/confurcation and employing formate as an alternate electron carrier to optimize their metabolisms for syntrophic growth.
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Affiliation(s)
- Pengfei Liu
- College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Yahai Lu
- College of Urban and Environmental Sciences, Peking University, Beijing, China
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12
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Schouw A, Vulcano F, Roalkvam I, Hocking WP, Reeves E, Stokke R, Bødtker G, Steen IH. Genome Analysis of Vallitalea guaymasensis Strain L81 Isolated from a Deep-Sea Hydrothermal Vent System. Microorganisms 2018; 6:E63. [PMID: 29973550 PMCID: PMC6163223 DOI: 10.3390/microorganisms6030063] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 06/28/2018] [Accepted: 06/29/2018] [Indexed: 12/21/2022] Open
Abstract
Abyssivirga alkaniphila strain L81T, recently isolated from a black smoker biofilm at the Loki’s Castle hydrothermal vent field, was previously described as a mesophilic, obligately anaerobic heterotroph able to ferment carbohydrates, peptides, and aliphatic hydrocarbons. The strain was classified as a new genus within the family Lachnospiraceae. Herein, its genome is analyzed and A. alkaniphila is reassigned to the genus Vallitalea as a new strain of V. guaymasensis, designated V. guaymasensis strain L81. The 6.4 Mbp genome contained 5651 protein encoding genes, whereof 4043 were given a functional prediction. Pathways for fermentation of mono-saccharides, di-saccharides, peptides, and amino acids were identified whereas a complete pathway for the fermentation of n-alkanes was not found. Growth on carbohydrates and proteinous compounds supported methane production in co-cultures with Methanoplanus limicola. Multiple confurcating hydrogen-producing hydrogenases, a putative bifurcating electron-transferring flavoprotein—butyryl-CoA dehydrogenase complex, and a Rnf-complex form a basis for the observed hydrogen-production and a putative reverse electron-transport in V. guaymasensis strain L81. Combined with the observation that n-alkanes did not support growth in co-cultures with M. limicola, it seemed more plausible that the previously observed degradation patterns of crude-oil in strain L81 are explained by unspecific activation and may represent a detoxification mechanism, representing an interesting ecological function. Genes encoding a capacity for polyketide synthesis, prophages, and resistance to antibiotics shows interactions with the co-occurring microorganisms. This study enlightens the function of the fermentative microorganisms from hydrothermal vents systems and adds valuable information on the bioprospecting potential emerging in deep-sea hydrothermal systems.
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Affiliation(s)
- Anders Schouw
- Department of Biological Sciences and KG Jebsen Centre for Deep Sea Research, University of Bergen, N-5020 Bergen, Norway.
| | - Francesca Vulcano
- Department of Biological Sciences and KG Jebsen Centre for Deep Sea Research, University of Bergen, N-5020 Bergen, Norway.
| | - Irene Roalkvam
- Department of Biological Sciences and KG Jebsen Centre for Deep Sea Research, University of Bergen, N-5020 Bergen, Norway.
| | - William Peter Hocking
- Department of Biological Sciences and KG Jebsen Centre for Deep Sea Research, University of Bergen, N-5020 Bergen, Norway.
| | - Eoghan Reeves
- Department of Earth Science and KG Jebsen Centre for Deep Sea Research, University of Bergen, N-5020 Bergen, Norway.
| | - Runar Stokke
- Department of Biological Sciences and KG Jebsen Centre for Deep Sea Research, University of Bergen, N-5020 Bergen, Norway.
| | - Gunhild Bødtker
- Centre for Integrated Petroleum Research (CIPR), Uni Research AS, Nygårdsgaten 112, N-5008 Bergen, Norway.
| | - Ida Helene Steen
- Department of Biological Sciences and KG Jebsen Centre for Deep Sea Research, University of Bergen, N-5020 Bergen, Norway.
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Liu Y, He P, Shao L, Zhang H, Lü F. Significant enhancement by biochar of caproate production via chain elongation. WATER RESEARCH 2017; 119:150-159. [PMID: 28456078 DOI: 10.1016/j.watres.2017.04.050] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 05/24/2023]
Abstract
In this study, biochar was introduced into a chain elongation system to enhance the bioproduction of caproate and caprylate. The concentration of caproate increased to 21.1 g/L upon the addition of biochar, which is the highest level of caproate reported for such a system to date when ethanol was used as electron donor. The addition of biochar created a tougher system with more stable microorganism community structure for chain elongation, in which no obvious inhibition by products or substrates was observed, moreover, the lag phase was reduced 2.3-fold compared to the system without biochar. These reinforcement effect of biochar are attributed to the enhanced conductivity due to the significant enrichment of functional microorganisms via the microbial network surrounding smaller biochar particles, and via the adsorption on the rough surfaces or pores of larger particles, which facilitated electron transfer. Higher amounts of extracellular polymer substances and higher conductivity induced by biochar could contribute to the reinforcement effect in chain elongation.
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Affiliation(s)
- Yuhao Liu
- State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China
| | - Pinjing He
- Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China; Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of P.R. China (MOHURD), China
| | - Liming Shao
- Centre for the Technology Research and Training on Household Waste in Small Towns & Rural Area, Ministry of Housing and Urban-Rural Development of P.R. China (MOHURD), China
| | - Hua Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China
| | - Fan Lü
- State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China.
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14
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Bretschger O, Carpenter K, Phan T, Suzuki S, Ishii S, Grossi-Soyster E, Flynn M, Hogan J. Functional and taxonomic dynamics of an electricity-consuming methane-producing microbial community. BIORESOURCE TECHNOLOGY 2015; 195:254-264. [PMID: 26178785 DOI: 10.1016/j.biortech.2015.06.129] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/25/2015] [Accepted: 06/26/2015] [Indexed: 06/04/2023]
Abstract
The functional and taxonomic microbial dynamics of duplicate electricity-consuming methanogenic communities were observed over a 6 months period to characterize the reproducibility, stability and recovery of electromethanogenic consortia. The highest rate of methanogenesis was 0.72 mg-CH4/L/day, which occurred during the third month of enrichment when multiple methanogenic phylotypes and associated Desulfovibrionaceae phylotypes were present in the electrode-associated microbial community. Results also suggest that electromethanogenic microbial communities are very sensitive to electron donor-limiting open-circuit conditions. A 45 min exposure to open-circuit conditions induced an 87% drop in volumetric methane production rates. Methanogenic performance recovered after 4 months to a maximum value of 0.30 mg-CH4/L/day under set potential operation (-700 mV vs Ag/AgCl); however, current consumption and biomass production was variable over time. Long-term functional and taxonomic analyses from experimental replicates provide new knowledge toward understanding how to enrich electromethanogenic communities and operate bioelectrochemical systems for stable and reproducible performance.
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Affiliation(s)
| | | | - Tony Phan
- J. Craig Venter Institute, La Jolla, CA, USA
| | - Shino Suzuki
- J. Craig Venter Institute, La Jolla, CA, USA; Japan Agency for Marine-Earth Science and Technology, Kochi, Japan
| | - Shun'ichi Ishii
- J. Craig Venter Institute, La Jolla, CA, USA; Japan Agency for Marine-Earth Science and Technology, Kochi, Japan
| | - Elysse Grossi-Soyster
- University Affiliated Research Center, UC Santa Cruz, Moffett Field, CA, USA; Stanford University, Stanford, CA, USA; NASA Ames Research Center, Moffett Field, CA, USA
| | | | - John Hogan
- NASA Ames Research Center, Moffett Field, CA, USA
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15
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Microbial metabolic networks in a complex electrogenic biofilm recovered from a stimulus-induced metatranscriptomics approach. Sci Rep 2015; 5:14840. [PMID: 26443302 PMCID: PMC4595844 DOI: 10.1038/srep14840] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 09/01/2015] [Indexed: 01/28/2023] Open
Abstract
Microorganisms almost always exist as mixed communities in nature. While the significance of microbial community activities is well appreciated, a thorough understanding about how microbial communities respond to environmental perturbations has not yet been achieved. Here we have used a combination of metagenomic, genome binning, and stimulus-induced metatranscriptomic approaches to estimate the metabolic network and stimuli-induced metabolic switches existing in a complex microbial biofilm that was producing electrical current via extracellular electron transfer (EET) to a solid electrode surface. Two stimuli were employed: to increase EET and to stop EET. An analysis of cell activity marker genes after stimuli exposure revealed that only two strains within eleven binned genomes had strong transcriptional responses to increased EET rates, with one responding positively and the other responding negatively. Potential metabolic switches between eleven dominant members were mainly observed for acetate, hydrogen, and ethanol metabolisms. These results have enabled the estimation of a multi-species metabolic network and the associated short-term responses to EET stimuli that induce changes to metabolic flow and cooperative or competitive microbial interactions. This systematic meta-omics approach represents a next step towards understanding complex microbial roles within a community and how community members respond to specific environmental stimuli.
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16
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Smith AL, Skerlos SJ, Raskin L. Membrane biofilm development improves COD removal in anaerobic membrane bioreactor wastewater treatment. Microb Biotechnol 2015; 8:883-94. [PMID: 26238293 PMCID: PMC4554476 DOI: 10.1111/1751-7915.12311] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 07/01/2015] [Accepted: 07/09/2015] [Indexed: 02/03/2023] Open
Abstract
Membrane biofilm development was evaluated to improve psychrophilic (15°C) anaerobic membrane bioreactor (AnMBR) treatment of domestic wastewater. An AnMBR containing three replicate submerged membrane housings with separate permeate collection was operated at three levels of membrane fouling by independently controlling biogas sparging for each membrane unit. High membrane fouling significantly improved permeate quality, but resulted in dissolved methane in the permeate at a concentration two to three times the equilibrium concentration predicted by Henry's law. Illumina sequencing of 16S rRNA targeting Bacteria and Archaea and reverse transcription-quantitative polymerase chain reaction targeting the methyl coenzyme-M reductase (mcrA) gene in methanogens indicated that the membrane biofilm was enriched in highly active methanogens and syntrophic bacteria. Restoring fouled membranes to a transmembrane pressure (TMP) near zero by increasing biogas sparging did not disrupt the biofilm's treatment performance, suggesting that microbes in the foulant layer were tightly adhered and did not significantly contribute to TMP. Dissolved methane oversaturation persisted without high TMP, implying that methanogenesis in the biofilm, rather than high TMP, was the primary driving force in methane oversaturation. The results describe an attractive operational strategy to improve treatment performance in low-temperature AnMBR by supporting syntrophy and methanogenesis in the membrane biofilm through controlled membrane fouling.
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Affiliation(s)
- Adam L Smith
- Department of Civil and Environmental Engineering, University of Michigan, 2350 Hayward Road, Ann Arbor, MI, 48109, USA
| | - Steven J Skerlos
- Department of Civil and Environmental Engineering, University of Michigan, 2350 Hayward Road, Ann Arbor, MI, 48109, USA.,Department of Mechanical Engineering, University of Michigan, 2350 Hayward Road, Ann Arbor, MI, 48109, USA
| | - Lutgarde Raskin
- Department of Civil and Environmental Engineering, University of Michigan, 2350 Hayward Road, Ann Arbor, MI, 48109, USA
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17
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Kouzuma A, Kato S, Watanabe K. Microbial interspecies interactions: recent findings in syntrophic consortia. Front Microbiol 2015; 6:477. [PMID: 26029201 PMCID: PMC4429618 DOI: 10.3389/fmicb.2015.00477] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/30/2015] [Indexed: 01/12/2023] Open
Abstract
Microbes are ubiquitous in our biosphere, and inevitably live in communities. They excrete a variety of metabolites and support the growth of other microbes in a community. According to the law of chemical equilibrium, the consumption of excreted metabolites by recipient microbes can accelerate the metabolism of donor microbes. This is the concept of syntrophy, which is a type of mutualism and governs the metabolism and growth of diverse microbes in natural and engineered ecosystems. A representative example of syntrophy is found in methanogenic communities, where reducing equivalents, e.g., hydrogen and formate, transfer between syntrophic partners. Studies have revealed that microbes involved in syntrophy have evolved molecular mechanisms to establish specific partnerships and interspecies communication, resulting in efficient metabolic cooperation. In addition, recent studies have provided evidence suggesting that microbial interspecies transfer of reducing equivalents also occurs as electric current via biotic (e.g., pili) and abiotic (e.g., conductive mineral and carbon particles) electric conduits. In this review, we describe these findings as examples of sophisticated cooperative behavior between different microbial species. We suggest that these interactions have fundamental roles in shaping the structure and activity of microbial communities.
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Affiliation(s)
- Atsushi Kouzuma
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences Tokyo, Japan
| | - Souichiro Kato
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology Sapporo, Japan
| | - Kazuya Watanabe
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences Tokyo, Japan
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18
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Mao X, Stenuit B, Polasko A, Alvarez-Cohen L. Efficient metabolic exchange and electron transfer within a syntrophic trichloroethene-degrading coculture of Dehalococcoides mccartyi 195 and Syntrophomonas wolfei. Appl Environ Microbiol 2015; 81:2015-24. [PMID: 25576615 PMCID: PMC4345365 DOI: 10.1128/aem.03464-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/02/2015] [Indexed: 01/07/2023] Open
Abstract
Dehalococcoides mccartyi 195 (strain 195) and Syntrophomonas wolfei were grown in a sustainable syntrophic coculture using butyrate as an electron donor and carbon source and trichloroethene (TCE) as an electron acceptor. The maximum dechlorination rate (9.9 ± 0.1 μmol day(-1)) and cell yield [(1.1 ± 0.3) × 10(8) cells μmol(-1) Cl(-)] of strain 195 maintained in coculture were, respectively, 2.6 and 1.6 times higher than those measured in the pure culture. The strain 195 cell concentration was about 16 times higher than that of S. wolfei in the coculture. Aqueous H2 concentrations ranged from 24 to 180 nM during dechlorination and increased to 350 ± 20 nM when TCE was depleted, resulting in cessation of butyrate fermentation by S. wolfei with a theoretical Gibbs free energy of -13.7 ± 0.2 kJ mol(-1). Carbon monoxide in the coculture was around 0.06 μmol per bottle, which was lower than that observed for strain 195 in isolation. The minimum H2 threshold value for TCE dechlorination by strain 195 in the coculture was 0.6 ± 0.1 nM. Cell aggregates during syntrophic growth were observed by scanning electron microscopy. The interspecies distances to achieve H2 fluxes required to support the measured dechlorination rates were predicted using Fick's law and demonstrated the need for aggregation. Filamentous appendages and extracellular polymeric substance (EPS)-like structures were present in the intercellular spaces. The transcriptome of strain 195 during exponential growth in the coculture indicated increased ATP-binding cassette transporter activities compared to the pure culture, while the membrane-bound energy metabolism related genes were expressed at stable levels.
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Affiliation(s)
- Xinwei Mao
- Department of Civil and Environmental Engineering, College of Engineering, University of California, Berkeley, Berkeley, California, USA
| | - Benoit Stenuit
- Department of Civil and Environmental Engineering, College of Engineering, University of California, Berkeley, Berkeley, California, USA
| | - Alexandra Polasko
- Department of Civil and Environmental Engineering, College of Engineering, University of California, Berkeley, Berkeley, California, USA
| | - Lisa Alvarez-Cohen
- Department of Civil and Environmental Engineering, College of Engineering, University of California, Berkeley, Berkeley, California, USA Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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19
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Dubé CD, Guiot SR. Direct Interspecies Electron Transfer in Anaerobic Digestion: A Review. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 151:101-15. [PMID: 26337845 DOI: 10.1007/978-3-319-21993-6_4] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Direct interspecies electrons transfer (DIET) is a syntrophic metabolism in which free electrons flow from one cell to another without being shuttled by reduced molecules such as molecular hydrogen or formate. As more and more microorganisms show a capacity for electron exchange, either to export or import them, it becomes obvious that DIET is a syntrophic metabolism that is much more present in nature than previously thought. This article reviews literature related to DIET, specifically in reference to anaerobic digestion. Anaerobic granular sludge, a biofilm, is a specialized microenvironment where syntrophic bacterial and archaeal organisms grow together in close proximity. Exoelectrogenic bacteria degrading organic substrates or intermediates need an electron sink and electrotrophic methanogens represent perfect partners to assimilate those electrons and produce methane. The granule extracellular polymeric substances by making the biofilm matrix more conductive, play a role as electrons carrier in DIET.
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Affiliation(s)
- Charles-David Dubé
- Department of Microbiology, Infectiology and Immunology, Université de Montréal, Montreal, Canada,
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20
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Piao H, Lachman M, Malfatti S, Sczyrba A, Knierim B, Auer M, Tringe SG, Mackie RI, Yeoman CJ, Hess M. Temporal dynamics of fibrolytic and methanogenic rumen microorganisms during in situ incubation of switchgrass determined by 16S rRNA gene profiling. Front Microbiol 2014; 5:307. [PMID: 25101058 PMCID: PMC4106096 DOI: 10.3389/fmicb.2014.00307] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 06/03/2014] [Indexed: 01/08/2023] Open
Abstract
The rumen microbial ecosystem is known for its biomass-degrading and methane-producing phenotype. Fermentation of recalcitrant plant material, comprised of a multitude of interwoven fibers, necessitates the synergistic activity of diverse microbial taxonomic groups that inhabit the anaerobic rumen ecosystem. Although interspecies hydrogen (H2) transfer, a process during which bacterially generated H2 is transferred to methanogenic Archaea, has obtained significant attention over the last decades, the temporal variation of the different taxa involved in in situ biomass-degradation, H2 transfer and the methanogenesis process remains to be established. Here we investigated the temporal succession of microbial taxa and its effect on fiber composition during rumen incubation using 16S rRNA amplicon sequencing. Switchgrass filled nylon bags were placed in the rumen of a cannulated cow and collected at nine time points for DNA extraction and 16S pyrotag profiling. The microbial community colonizing the air-dried and non-incubated (0 h) switchgrass was dominated by members of the Bacilli (recruiting 63% of the pyrotag reads). During in situ incubation of the switchgrass, two major shifts in the community composition were observed: Bacilli were replaced within 30 min by members belonging to the Bacteroidia and Clostridia, which recruited 34 and 25% of the 16S rRNA reads generated, respectively. A second significant shift was observed after 16 h of rumen incubation, when members of the Spirochaetes and Fibrobacteria classes became more abundant in the fiber-adherent community. During the first 30 min of rumen incubation ~13% of the switchgrass dry matter was degraded, whereas little biomass degradation appeared to have occurred between 30 min and 4 h after the switchgrass was placed in the rumen. Interestingly, methanogenic members of the Euryarchaeota (i.e., Methanobacteria) increased up to 3-fold during this period of reduced biomass-degradation, with peak abundance just before rates of dry matter degradation increased again. We hypothesize that during this period microbial-mediated fibrolysis was temporarily inhibited until H2 was metabolized into CH4 by methanogens. Collectively, our results demonstrate the importance of inter-species interactions for the biomass-degrading and methane-producing phenotype of the rumen microbiome—both microbially facilitated processes with global significance.
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Affiliation(s)
- Hailan Piao
- Systems Microbiology and Biotechnology Group, School of Molecular Biosciences, Washington State University Richland, WA, USA
| | - Medora Lachman
- Department of Animal and Range Sciences, Montana State University Bozeman, MT, USA
| | - Stephanie Malfatti
- Lawrence Livermore National Laboratory, Biosciences and Biotechnology Division Livermore, CA, USA
| | - Alexander Sczyrba
- Faculty of Technology and Center for Biotechnology, Bielefeld University Bielefeld, Germany
| | - Bernhard Knierim
- Lawrence Berkeley National Laboratory, Life Sciences Division Berkeley, CA, USA
| | - Manfred Auer
- Lawrence Berkeley National Laboratory, Life Sciences Division Berkeley, CA, USA
| | - Susannah G Tringe
- Prokaryote Super Program, DOE Joint Genome Institute Walnut Creek, CA, USA
| | - Roderick I Mackie
- Department of Animal Sciences and Institute for Genomic Biology, University of Illinois, Urbana-Champaign IL, USA
| | - Carl J Yeoman
- Department of Animal and Range Sciences, Montana State University Bozeman, MT, USA
| | - Matthias Hess
- Systems Microbiology and Biotechnology Group, School of Molecular Biosciences, Washington State University Richland, WA, USA ; Prokaryote Super Program, DOE Joint Genome Institute Walnut Creek, CA, USA ; Energy and Efficiency Division, Chemical and Biological Process Development Group, Pacific Northwest National Laboratory Richland, WA, USA
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21
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Kosaka T, Toh H, Fujiyama A, Sakaki Y, Watanabe K, Meng XY, Hanada S, Toyoda A. Physiological and genetic basis for self-aggregation of a thermophilic hydrogenotrophic methanogen, Methanothermobacter strain CaT2. ENVIRONMENTAL MICROBIOLOGY REPORTS 2014; 6:268-277. [PMID: 24983531 DOI: 10.1111/1758-2229.12128] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 11/05/2013] [Indexed: 06/03/2023]
Abstract
Several thermophilic hydrogenotrophic methanogens naturally aggregate in their habitats in association with hydrogen-producing bacteria for efficient transfer of the methane fermentation intermediates to produce methane. However, physiology of aggregation and the identity of aggregation-specific genes remain to be elucidated. Here, we isolated and characterized a hydrogen and formate-utilizing Methanothermobacter sp. CaT2 that is capable of self-aggregation and utilizing formate. CaT2 produced methane from propionate oxidation in association with a syntrophic propionate-oxidizing bacterium faster than other methanogens, including Methanothermobacter thermautotrophicus ΔH and Methanothermobacter thermautotrophicus Z-245. CaT2 also aggregated throughout the culture period and was coated with polysaccharides, which was not found on the ΔH and Z-245 cells. Sugar content (particularly of rhamnose and mannose) was also higher in the CaT2 cells than the ΔH and Z-245 cells. Comparative genomic analysis of CaT2 indicated that four candidate genes, all of which encode glycosyltransferase, were involved in aggregation of CaT2. Transcriptional analysis showed that one glycosyltransferase gene was expressed at relatively high levels under normal growth conditions. The polysaccharide layer on the CaT2 cell surface, which is probably assembled by these glycosyltransferases, may be involved in cell aggregation.
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Affiliation(s)
- Tomoyuki Kosaka
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan; PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama, 332-0012, Japan; Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8566, Japan
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22
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Meyer B, Kuehl JV, Deutschbauer AM, Arkin AP, Stahl DA. Flexibility of syntrophic enzyme systems in Desulfovibrio species ensures their adaptation capability to environmental changes. J Bacteriol 2013; 195:4900-14. [PMID: 23974031 PMCID: PMC3807489 DOI: 10.1128/jb.00504-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 08/20/2013] [Indexed: 12/31/2022] Open
Abstract
The mineralization of organic matter in anoxic environments relies on the cooperative activities of hydrogen producers and consumers obligately linked by interspecies metabolite exchange in syntrophic consortia that may include sulfate reducing species such as Desulfovibrio. To evaluate the metabolic flexibility of syntrophic Desulfovibrio to adapt to naturally fluctuating methanogenic environments, we studied Desulfovibrio alaskensis strain G20 grown in chemostats under respiratory and syntrophic conditions with alternative methanogenic partners, Methanococcus maripaludis and Methanospirillum hungatei, at different growth rates. Comparative whole-genome transcriptional analyses, complemented by G20 mutant strain growth experiments and physiological data, revealed a significant influence of both energy source availability (as controlled by dilution rate) and methanogen on the electron transfer systems, ratios of interspecies electron carriers, energy generating systems, and interspecies physical associations. A total of 68 genes were commonly differentially expressed under syntrophic versus respiratory lifestyle. Under low-energy (low-growth-rate) conditions, strain G20 further had the capacity to adapt to the metabolism of its methanogenic partners, as shown by its differing gene expression of enzymes involved in the direct metabolic interactions (e.g., periplasmic hydrogenases) and the ratio shift in electron carriers used for interspecies metabolite exchange (hydrogen/formate). A putative monomeric [Fe-Fe] hydrogenase and Hmc (high-molecular-weight-cytochrome c3) complex-linked reverse menaquinone (MQ) redox loop become increasingly important for the reoxidation of the lactate-/pyruvate oxidation-derived redox pair, DsrC(red) and Fd(red), relative to the Qmo-MQ-Qrc (quinone-interacting membrane-bound oxidoreductase; quinone-reducing complex) loop. Together, these data underscore the high enzymatic and metabolic adaptive flexibility that likely sustains Desulfovibrio in naturally fluctuating methanogenic environments.
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Affiliation(s)
- Birte Meyer
- Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA
| | - Jennifer V. Kuehl
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Adam M. Deutschbauer
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Adam P. Arkin
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - David A. Stahl
- Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA
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Variation among Desulfovibrio species in electron transfer systems used for syntrophic growth. J Bacteriol 2012; 195:990-1004. [PMID: 23264581 DOI: 10.1128/jb.01959-12] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mineralization of organic matter in anoxic environments relies on the cooperative activities of hydrogen producers and consumers linked by interspecies electron transfer in syntrophic consortia that may include sulfate-reducing species (e.g., Desulfovibrio). Physiological differences and various gene repertoires implicated in syntrophic metabolism among Desulfovibrio species suggest considerable variation in the biochemical basis of syntrophy. In this study, comparative transcriptional and mutant analyses of Desulfovibrio alaskensis strain G20 and Desulfovibrio vulgaris strain Hildenborough growing syntrophically with Methanococcus maripaludis on lactate were used to develop new and revised models for their alternative electron transfer and energy conservation systems. Lactate oxidation by strain G20 generates a reduced thiol-disulfide redox pair(s) and ferredoxin that are energetically coupled to H(+)/CO(2) reduction by periplasmic formate dehydrogenase and hydrogenase via a flavin-based reverse electron bifurcation process (electron confurcation) and a menaquinone (MQ) redox loop-mediated reverse electron flow involving the membrane-bound Qmo and Qrc complexes. In contrast, strain Hildenborough uses a larger number of cytoplasmic and periplasmic proteins linked in three intertwining pathways to couple H(+) reduction to lactate oxidation. The faster growth of strain G20 in coculture is associated with a kinetic advantage conferred by the Qmo-MQ-Qrc loop as an electron transfer system that permits higher lactate oxidation rates under elevated hydrogen levels (thereby enhancing methanogenic growth) and use of formate as the main electron-exchange mediator (>70% electron flux), as opposed to the primarily hydrogen-based exchange by strain Hildenborough. This study further demonstrates the absence of a conserved gene core in Desulfovibrio that would determine the ability for a syntrophic lifestyle.
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Enoki M, Shinzato N, Sato H, Nakamura K, Kamagata Y. Comparative proteomic analysis of Methanothermobacter themautotrophicus ΔH in pure culture and in co-culture with a butyrate-oxidizing bacterium. PLoS One 2011; 6:e24309. [PMID: 21904627 PMCID: PMC3164167 DOI: 10.1371/journal.pone.0024309] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 08/06/2011] [Indexed: 11/21/2022] Open
Abstract
To understand the physiological basis of methanogenic archaea living on interspecies H2 transfer, the protein expression of a hydrogenotrophic methanogen, Methanothermobacter thermautotrophicus strain ΔH, was investigated in both pure culture and syntrophic coculture with an anaerobic butyrate oxidizer Syntrophothermus lipocalidus strain TGB-C1 as an H2 supplier. Comparative proteomic analysis showed that global protein expression of methanogen cells in the model coculture was substantially different from that of pure cultured cells. In brief, in syntrophic coculture, although methanogenesis-driven energy generation appeared to be maintained by shifting the pathway to the alternative methyl coenzyme M reductase isozyme I and cofactor F420-dependent process, the machinery proteins involved in carbon fixation, amino acid synthesis, and RNA/DNA metabolisms tended to be down-regulated, indicating restrained cell growth rather than vigorous proliferation. In addition, our proteome analysis revealed that α subunits of proteasome were differentially acetylated between the two culture conditions. Since the relevant modification has been suspected to regulate proteolytic activity of the proteasome, the global protein turnover rate could be controlled under syntrophic growth conditions. To our knowledge, the present study is the first report on N-acetylation of proteasome subunits in methanogenic archaea. These results clearly indicated that physiological adaptation of hydrogenotrophic methanogens to syntrophic growth is more complicated than that of hitherto proposed.
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Affiliation(s)
- Miho Enoki
- Research Institute of Biological Resources, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
- Marine Biotechnology Institute, Kamaishi, Iwate, Japan
| | - Naoya Shinzato
- Research Institute of Biological Resources, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
- Tropical Biosphere Research Center, University of the Ryukyus, Nishihara-cho, Okinawa, Japan
- * E-mail:
| | - Hiroaki Sato
- Research Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology (AIST), Japan
| | - Kohei Nakamura
- Research Institute of Biological Resources, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
- Faculty of Applied Biological Sciences, Gifu University, Gifu, Gifu, Japan
| | - Yoichi Kamagata
- Research Institute of Biological Resources, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
- Research Institute of Genome-Based Biofactory, National Institute of Advanced Industrial Science and Technology (AIST), Toyohira-ku, Sapporo, Japan
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25
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Weiss S, Zankel A, Lebuhn M, Petrak S, Somitsch W, Guebitz GM. Investigation of mircroorganisms colonising activated zeolites during anaerobic biogas production from grass silage. BIORESOURCE TECHNOLOGY 2011; 102:4353-4359. [PMID: 21277767 DOI: 10.1016/j.biortech.2010.12.076] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 12/18/2010] [Accepted: 12/20/2010] [Indexed: 05/30/2023]
Abstract
The colonisation of activated zeolites (i.e. clinoptilolites) as carriers for microorganisms involved in the biogas process was investigated. Zeolite particle sizes of 1.0-2.5mm were introduced to anaerobic laboratory batch-cultures and to continuously operated bioreactors during biogas production from grass silage. Incubation over 5-84 days led to the colonisation of zeolite surfaces in small batch-cultures (500 ml) and even in larger scaled and flow-through disturbed bioreactors (28 l). Morphological insights were obtained by using scanning electron microscopy (SEM). Single strand conformation polymorphism (SSCP) analysis based on amplification of bacterial and archaeal 16S rRNA fragments demonstrated structurally distinct populations preferring zeolite as operational environment. via sequence analysis conspicuous bands from SSCP patterns were identified. Populations immobilised on zeolite (e.g. Ruminofilibacter xylanolyticum) showed pronounced hydrolytic enzyme activity (xylanase) shortly after re-incubation in sterilised sludge on model substrate. In addition, the presence of methanogenic archaea on zeolite particles was demonstrated.
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Affiliation(s)
- S Weiss
- Department of Environmental Biotechnology, Graz University of Technology, Petersgasse 12, 8010 Graz, Austria
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26
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Breugelmans P, Horemans B, Hofkens J, Springael D. Response to mixed substrate feeds of the structure and activity of a linuron-degrading triple-species biofilm. Res Microbiol 2010; 161:660-6. [DOI: 10.1016/j.resmic.2010.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 06/09/2010] [Accepted: 06/11/2010] [Indexed: 11/16/2022]
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27
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Cavaleiro AJ, Sousa DZ, Alves MM. Methane production from oleate: assessing the bioaugmentation potential of Syntrophomonas zehnderi. WATER RESEARCH 2010; 44:4940-4947. [PMID: 20696454 DOI: 10.1016/j.watres.2010.07.039] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 07/02/2010] [Accepted: 07/13/2010] [Indexed: 05/29/2023]
Abstract
The potential for improving long-chain fatty acids (LCFA) conversion to methane was evaluated by bioaugmenting a non-acclimated anaerobic granular sludge with Syntrophomonas zehnderi. Batch bioaugmentation assays were performed with and without the solid microcarrier sepiolite, using 1 mM oleate as sole carbon and energy source. When S. zehnderi was added to the anaerobic sludge methane production from oleate was faster. High methane yields, i.e. 89 ± 5% and 72 ± 1%, were observed in bioaugmented assays in the absence and presence of sepiolite, respectively. Sepiolite stimulated a faster methane production from oleate and prevented the accumulation of acetate. Acetoclastic activity was affected by oleate in the absence of sepiolite, where methane production rate was 26% lower than in assays with microcarrier.
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Affiliation(s)
- A J Cavaleiro
- Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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28
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Sieber JR, Sims DR, Han C, Kim E, Lykidis A, Lapidus AL, McDonnald E, Rohlin L, Culley DE, Gunsalus R, McInerney MJ. The genome of Syntrophomonas wolfei: new insights into syntrophic metabolism and biohydrogen production. Environ Microbiol 2010; 12:2289-301. [PMID: 21966920 DOI: 10.1111/j.1462-2920.2010.02237.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Syntrophomonas wolfei is a specialist, evolutionarily adapted for syntrophic growth with methanogens and other hydrogen- and/or formate-using microorganisms. This slow-growing anaerobe has three putative ribosome RNA operons, each of which has 16S rRNA and 23S rRNA genes of different length and multiple 5S rRNA genes. The genome also contains 10 RNA-directed, DNA polymerase genes. Genomic analysis shows that S. wolfei relies solely on the reduction of protons, bicarbonate or unsaturated fatty acids to re-oxidize reduced cofactors. Syntrophomonas wolfei lacks the genes needed for aerobic or anaerobic respiration and has an exceptionally limited ability to create ion gradients. An ATP synthase and a pyrophosphatase were the only systems detected capable of creating an ion gradient. Multiple homologues for β-oxidation genes were present even though S. wolfei uses a limited range of fatty acids from four to eight carbons in length.Syntrophomonas wolfei, other syntrophic metabolizers with completed genomic sequences, and thermophilic anaerobes known to produce high molar ratios of hydrogen from glucose have genes to produce H(2) from NADH by an electron bifurcation mechanism. Comparative genomic analysis also suggests that formate production from NADH may involve electron bifurcation. A membrane-bound, iron-sulfur oxidoreductase found in S. wolfei and Syntrophus aciditrophicus may be uniquely involved in reverse electron transport during syntrophic fatty acid metabolism. The genome sequence of S. wolfei reveals several core reactions that may be characteristic of syntrophic fatty acid metabolism and illustrates how biological systems produce hydrogen from thermodynamically difficult reactions.
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Affiliation(s)
- Jessica R Sieber
- Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA
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Kato S, Watanabe K. Ecological and Evolutionary Interactions in Syntrophic Methanogenic Consortia. Microbes Environ 2010; 25:145-51. [DOI: 10.1264/jsme2.me10122] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Kazuya Watanabe
- Hashimoto Light Energy Conversion Project, ERATO, JST
- Research Center for Advanced Science and Technology, University of Tokyo
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Plugge CM, Jiang B, de Bok FAM, Tsai C, Stams AJM. Effect of tungsten and molybdenum on growth of a syntrophic coculture of Syntrophobacter fumaroxidans and Methanospirillum hungatei. Arch Microbiol 2008; 191:55-61. [PMID: 18795263 DOI: 10.1007/s00203-008-0428-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Revised: 08/15/2008] [Accepted: 08/21/2008] [Indexed: 11/28/2022]
Abstract
The effect of tungsten (W) and molybdenum (Mo) on the growth of Syntrophobacter fumaroxidans and Methanospirillum hungatei was studied in syntrophic cultures and the pure cultures of both the organisms. Cells that were grown syntropically were separated by Percoll density centrifugation. Measurement of hydrogenase and formate dehydrogenase levels in cell extracts of syntrophically grown cells correlated with the methane formation rates in the co-cultures. The effect of W and Mo on the activity of formate dehydrogenase was considerable in both the organisms, whereas hydrogenase activity remained relatively constant. Depletion of tungsten and/or molybdenum, however, did not affect the growth of the pure culture of S. fumaroxidans on propionate plus fumarate significantly, although the specific activities of hydrogenase and especially formate dehydrogenase were influenced by the absence of Mo and W. This indicates that the organism has a low W or Mo requirement under these conditions. Growth of M. hungatei on either formate or H2/CO2 required tungsten, and molybdenum could replace tungsten to some extent. Our results suggest a more prominent role for H2 as electron carrier in the syntrophic conversion of propionate, when the essential trace metals W and Mo for the functioning of formate dehydrogenase are depleted.
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Affiliation(s)
- Caroline M Plugge
- Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB, Wageningen, The Netherlands.
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31
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Free A, Barton NH. Do evolution and ecology need the Gaia hypothesis? Trends Ecol Evol 2007; 22:611-9. [PMID: 17954000 DOI: 10.1016/j.tree.2007.07.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 07/06/2007] [Accepted: 07/06/2007] [Indexed: 11/27/2022]
Abstract
Gaia theory, which describes the life-environment system of the Earth as stable and self-regulating, has remained at the fringes of mainstream biological science owing to its historically inadequate definition and apparent incompatibility with individual-level natural selection. The key issue is whether and why the biosphere might tend towards stability and self-regulation. We review the various ways in which these issues have been addressed by evolutionary and ecological theory, and relate these to 'Gaia theory'. We then ask how this theory extends the perspectives offered by these disciplines, and how it might be tested by novel modelling approaches and laboratory experiments using emergent technologies.
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Affiliation(s)
- Andrew Free
- Centre for the Study of Environmental Change and Sustainability, University of Edinburgh, Edinburgh, EH9 3JN, UK.
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32
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Narihiro T, Sekiguchi Y. Microbial communities in anaerobic digestion processes for waste and wastewater treatment: a microbiological update. Curr Opin Biotechnol 2007; 18:273-8. [PMID: 17462878 DOI: 10.1016/j.copbio.2007.04.003] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2006] [Revised: 03/20/2007] [Accepted: 04/17/2007] [Indexed: 11/28/2022]
Abstract
Anaerobic digestion technology is the biological treatment of organic waste and wastewater without input of external electron acceptors (oxygen), offering the potential to reduce treatment cost and to produce energy as 'biogas' (methane) from organic waste. The technology has become enormously popular in the past two decades, and knowledge of microbiological aspects of the technology has also accumulated significantly. Major advances have been made in elucidating the diversity of yet-to-be cultured microbes in anaerobic digestion processes, and the cultivation of uncultured organisms is of great interest with regard to gaining insights into the function of these organisms. In addition, recent advances have been made in the development of microbial fuel cells as an alternative, direct energy-yielding treatment system.
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Affiliation(s)
- Takashi Narihiro
- Bio-Measurement Research Group, Institute for Biological Resources and Functions, National Institute of Advanced Science and Technology (AIST), AIST Tsukuba Central 6, Ibaraki 305-8566, Japan
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34
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McInerney MJ, Rohlin L, Mouttaki H, Kim U, Krupp RS, Rios-Hernandez L, Sieber J, Struchtemeyer CG, Bhattacharyya A, Campbell JW, Gunsalus RP. The genome of Syntrophus aciditrophicus: life at the thermodynamic limit of microbial growth. Proc Natl Acad Sci U S A 2007; 104:7600-5. [PMID: 17442750 PMCID: PMC1863511 DOI: 10.1073/pnas.0610456104] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biochemically, the syntrophic bacteria constitute the missing link in our understanding of anaerobic flow of carbon in the biosphere. The completed genome sequence of Syntrophus aciditrophicus SB, a model fatty acid- and aromatic acid-degrading syntrophic bacterium, provides a glimpse of the composition and architecture of the electron transfer and energy-transducing systems needed to exist on marginal energy economies of a syntrophic lifestyle. The genome contains 3,179,300 base pairs and 3,169 genes where 1,618 genes were assigned putative functions. Metabolic reconstruction of the gene inventory revealed that most biosynthetic pathways of a typical Gram-negative microbe were present. A distinctive feature of syntrophic metabolism is the need for reverse electron transport; the presence of a unique Rnf-type ion-translocating electron transfer complex, menaquinone, and membrane-bound Fe-S proteins with associated heterodisulfide reductase domains suggests mechanisms to accomplish this task. Previously undescribed approaches to degrade fatty and aromatic acids, including multiple AMP-forming CoA ligases and acyl-CoA synthetases seem to be present as ways to form and dissipate ion gradients by using a sodium-based energy strategy. Thus, S. aciditrophicus, although nutritionally self-sufficient, seems to be a syntrophic specialist with limited fermentative and respiratory metabolism. Genomic analysis confirms the S. aciditrophicus metabolic and regulatory commitment to a nonconventional mode of life compared with our prevailing understanding of microbiology.
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Affiliation(s)
- Michael J. McInerney
- *Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019
| | - Lars Rohlin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095
| | - Housna Mouttaki
- *Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019
| | - UnMi Kim
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095
| | - Rebecca S. Krupp
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095
| | - Luis Rios-Hernandez
- *Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019
| | - Jessica Sieber
- *Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019
| | | | | | - John W. Campbell
- Integrated Genomics, 2201 West Campbell Park Drive, Chicago, IL 60612; and
| | - Robert P. Gunsalus
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095
- To whom correspondence should be addressed. E-mail:
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35
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Verstraete W, Wittebolle L, Heylen K, Vanparys B, de Vos P, van de Wiele T, Boon N. Microbial Resource Management: The Road To Go for Environmental Biotechnology. Eng Life Sci 2007. [DOI: 10.1002/elsc.200620176] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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