201
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van Grinsven S, Sinninghe Damsté JS, Villanueva L. Assessing the Effect of Humic Substances and Fe(III) as Potential Electron Acceptors for Anaerobic Methane Oxidation in a Marine Anoxic System. Microorganisms 2020; 8:E1288. [PMID: 32846903 PMCID: PMC7564286 DOI: 10.3390/microorganisms8091288] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/06/2020] [Accepted: 08/17/2020] [Indexed: 12/13/2022] Open
Abstract
Marine anaerobic methane oxidation (AOM) is generally assumed to be coupled to sulfate reduction, via a consortium of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB). ANME-1 are, however, often found as single cells, or only loosely aggregated with SRB, suggesting they perform a form of AOM independent of sulfate reduction. Oxidized metals and humic substances have been suggested as potential electron acceptors for ANME, but up to now, AOM linked to reduction of these compounds has only been shown for the ANME-2 and ANME-3 clades. Here, the effect of the electron acceptors anthraquinone-disulfonate (AQDS), a humic acids analog, and Fe3+ on anaerobic methane oxidation were assessed by incubation experiments with anoxic Black Sea water containing ANME-1b. Incubation experiments with 13C-methane and AQDS showed a stimulating effect of AQDS on methane oxidation. Fe3+ enhanced the ANME-1b abundance but did not substantially increase methane oxidation. Sodium molybdate, which was added as an inhibitor of sulfate reduction, surprisingly enhanced methane oxidation, possibly related to the dominant abundance of Sulfurospirillum in those incubations. The presented data suggest the potential involvement of ANME-1b in AQDS-enhanced anaerobic methane oxidation, possibly via electron shuttling to AQDS or via interaction with other members of the microbial community.
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Affiliation(s)
- Sigrid van Grinsven
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Utrecht University, 1797 SZ ’t Horntje, Texel, The Netherlands; (J.S.S.D.); (L.V.)
| | - Jaap S. Sinninghe Damsté
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Utrecht University, 1797 SZ ’t Horntje, Texel, The Netherlands; (J.S.S.D.); (L.V.)
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, 3584 CB Utrecht, The Netherlands
| | - Laura Villanueva
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Utrecht University, 1797 SZ ’t Horntje, Texel, The Netherlands; (J.S.S.D.); (L.V.)
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202
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Raggi L, García-Guevara F, Godoy-Lozano EE, Martínez-Santana A, Escobar-Zepeda A, Gutierrez-Rios RM, Loza A, Merino E, Sanchez-Flores A, Licea-Navarro A, Pardo-Lopez L, Segovia L, Juarez K. Metagenomic Profiling and Microbial Metabolic Potential of Perdido Fold Belt (NW) and Campeche Knolls (SE) in the Gulf of Mexico. Front Microbiol 2020; 11:1825. [PMID: 32903729 PMCID: PMC7438803 DOI: 10.3389/fmicb.2020.01825] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/10/2020] [Indexed: 01/04/2023] Open
Abstract
The Gulf of Mexico (GoM) is a particular environment that is continuously exposed to hydrocarbon compounds that may influence the microbial community composition. We carried out a metagenomic assessment of the bacterial community to get an overall view of this geographical zone. We analyzed both taxonomic and metabolic markers profiles to explain how the indigenous GoM microorganims participate in the biogeochemical cycling. Two geographically distant regions in the GoM, one in the north-west (NW) and one in the south-east (SE) of the GoM were analyzed and showed differences in their microbial composition and metabolic potential. These differences provide evidence the delicate equilibrium that sustains microbial communities and biogeochemical cycles. Based on the taxonomy and gene groups, the NW are more oxic sediments than SE ones, which have anaerobic conditions. Both water and sediments show the expected sulfur, nitrogen, and hydrocarbon metabolism genes, with particularly high diversity of the hydrocarbon-degrading ones. Accordingly, many of the assigned genera were associated with hydrocarbon degradation processes, Nitrospira and Sva0081 were the most abundant in sediments, while Vibrio, Alteromonas, and Alcanivorax were mostly detected in water samples. This basal-state analysis presents the GoM as a potential source of aerobic and anaerobic hydrocarbon degradation genes important for the ecological dynamics of hydrocarbons and the potential use for water and sediment bioremediation processes.
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Affiliation(s)
- Luciana Raggi
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
- CONACYT-Laboratorio de Biotecnología Acuícola, Instituto de Investigaciones Agropecuarias y Forestales, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mexico
| | | | - E. Ernestina Godoy-Lozano
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
- Centro de Investigación Sobre Enfermedades Infecciosas, Departamento de Bioinformática en Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Mexico
| | | | | | | | - Antonio Loza
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Enrique Merino
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | | | - Alexei Licea-Navarro
- Laboratorio de Inmunología Molecular y Biotoxinas, Departamento de Innovación Biomedica, CICESE, Ensenada, Mexico
| | - Liliana Pardo-Lopez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Lorenzo Segovia
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Katy Juarez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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203
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Wang H, Li J, Zhao Y, Xu C, Zhang K, Li J, Yan L, Gu JD, Wei D, Wang W. Establishing practical strategies to run high loading corn stover anaerobic digestion: Methane production performance and microbial responses. BIORESOURCE TECHNOLOGY 2020; 310:123364. [PMID: 32334357 DOI: 10.1016/j.biortech.2020.123364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/06/2020] [Accepted: 04/07/2020] [Indexed: 06/11/2023]
Abstract
It is significant to understand corn stover (CS) in anaerobic digestion (AD) under high organic loadings. A semi-continuous mesophilic (37 ± 1 °C) CS AD was conducted in this study with increasing loadings. The initial total solids (TS) gradually increased with 1% gradient at every 10 days from 8% to 15% until the system was acidified. Adding different ratios of cattle manure (CM) (20%, 30% and 40% (v/v)) to rescue this system back to a stable operation was adopted. The diversity of bacteria and archaea was analyzed by 16S rRNA gene sequencing technology. The results showed that when loading TS content was increased to 15%, AD system was acidized with pH value of 5.13. 30% of CM was the optimal ratio to recover biogas production. High abundance (31.07%) of Bathyarchaeota was first found in AD system. Acidification of high loading CS AD can be highly correlating with bacterial community, specially Clostridium and Caproiciproducens.
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Affiliation(s)
- Haipeng Wang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Agro-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China
| | - Jiawei Li
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Agro-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China
| | - Yiquan Zhao
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Agro-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China
| | - Congfeng Xu
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Agro-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China
| | - Keqiang Zhang
- Agro-Environmental Protection Institute of Ministry of Agriculture, Tianjin 300191, China
| | - Jiajia Li
- Agro-Environmental Protection Institute of Ministry of Agriculture, Tianjin 300191, China
| | - Lei Yan
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Agro-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China
| | - Ji-Dong Gu
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Hong Kong 999077, China
| | - Dan Wei
- Institute of Plant Nutrition and Resources, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100081, China
| | - Weidong Wang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Agro-Waste in Cold Region, College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China.
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204
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Lam TYC, Mei R, Wu Z, Lee PKH, Liu WT, Lee PH. Superior resolution characterisation of microbial diversity in anaerobic digesters using full-length 16S rRNA gene amplicon sequencing. WATER RESEARCH 2020; 178:115815. [PMID: 32380296 DOI: 10.1016/j.watres.2020.115815] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 03/18/2020] [Accepted: 04/08/2020] [Indexed: 05/24/2023]
Abstract
In the past decade, the characterisation of the microbial community in anaerobic digestion was primarily done by using high-throughput short-read amplicon sequencing. However, the short-read approach has inherent primer bias and low phylogenetic resolution. Our previous study using Illumina MiSeq suggested that the heterogeneity of AD microbiome was operation-driven. To advance our knowledge towards the complexity of the AD microbiome, we performed full-length 16S rRNA gene amplicon sequencing using PacBio Sequel for a more accurate phylogenetic identification. To this end, purified DNA samples from 19 global anaerobic digesters were sequenced. Sixteen methanogenic archaea were identified at the species level. Among them, Methanosarcina horonobensis and Methanosarcina flavescens had significant presence under specific operating conditions. Methanothrix concilii presented in all digesters sequenced. Unexpectedly, over 90% of the Smithella detected were closely related to alkane-degrading Smithella strains D17 and M82, not Smithella propionica. Using LEfSe and network analysis, the interspecies relationship between the fermentative and syntrophic bacteria was addressed. Comparison of the short- and long-read sequencing results were performed and discussed. From sample preparation to data analysis, this work characterised the digester microbiomes in a superior resolution.
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Affiliation(s)
- Theo Y C Lam
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
| | - Ran Mei
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | - Zhuoying Wu
- Department of Civil and Environmental Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Patrick K H Lee
- School of Energy and Environment, City University of Hong Kong, Kowloon, Hong Kong
| | - Wen-Tso Liu
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | - Po-Heng Lee
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; Department of Civil and Environmental Engineering, Imperial College London, London, SW7 2AZ, UK.
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205
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Xu L, Zhuang GC, Montgomery A, Liang Q, Joye SB, Wang F. Methyl-compounds driven benthic carbon cycling in the sulfate-reducing sediments of South China Sea. Environ Microbiol 2020; 23:641-651. [PMID: 32506654 DOI: 10.1111/1462-2920.15110] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/30/2020] [Indexed: 11/29/2022]
Abstract
Methane is a potent greenhouse gas; methane production and consumption within seafloor sediments has generated intense interest. Anaerobic oxidation of methane (AOM) and methanogenesis (MOG) primarily occur at the depth of the sulfate-methane transition zone or underlying sediment respectively. Methanogenesis can also occur in the sulfate-reducing sediments through the utilization of non-competitive methylated compounds; however, the occurrence and importance of this process are not fully understood. Here, we combined a variety of data, including geochemical measurements, rate measurements and molecular analyses to demonstrate the presence of a cryptic methane cycle in sulfate-reducing sediments from the continental shelf of the northern South China Sea. The abundance of methanogenic substrates as well as the high MOG rates from methylated compounds indicated that methylotrophic methanogenesis was the dominant methanogenic pathway; this conclusion was further supported by the presence of the methylotrophic genus Methanococcoides. High potential rates of AOM were observed in the sediments, indicating that methane produced in situ could be oxidized simultaneously by AOM, presumably by ANME-2a/b as indicated by 16S rRNA gene analysis. A significant correlation between the relative abundance of methanogens and methanotrophs was observed over sediment depth, indicating that methylotrophic methanogenesis could potentially fuel AOM in this environment. In addition, higher potential rates of AOM than sulfate reduction rates at in situ methane conditions were observed, making alternative electron acceptors important to support AOM in sulfate-reducing sediment. AOM rates were stimulated by the addition of Fe/Mn oxides, suggesting AOM could be partially coupled to metal oxide reduction. These results suggest that methyl-compounds driven methane production drives a cryptic methane cycling and fuels AOM coupled to the reduction of sulfate and other electron acceptors.
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Affiliation(s)
- Lei Xu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Guang-Chao Zhuang
- Frontiers Science Centre for Deep Ocean Multispheres and Earth System (FDOMES)/Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, China.,Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.,Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA
| | - Andrew Montgomery
- Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA
| | - Qianyong Liang
- Guangzhou Marine Geological Survey, China Geological Survey, Guangzhou, 510740, China
| | - Samantha B Joye
- Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA
| | - Fengping Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,School of Oceanography, Shanghai Jiao Tong University, Shanghai, 200240, China
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206
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Tschoeke DA, Coutinho FH, Leomil L, Cavalcanti G, Silva BS, Garcia GD, Dos Anjos LC, Nascimento LB, Moreira LS, Otsuki K, Cordeiro RC, Rezende CE, Thompson FL, Thompson CC. New bacterial and archaeal lineages discovered in organic rich sediments of a large tropical Bay. Mar Genomics 2020; 54:100789. [PMID: 32563694 DOI: 10.1016/j.margen.2020.100789] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 12/15/2022]
Abstract
The nutrient and oxygen gradient present in marine sediments promotes high levels of microbial diversity. We applied metagenomics and biogeochemical tools to analyze microbial communities in different sediment depths (0-4 m below sea floor, mbsf) from Guanabara Bay, Brazil, a brackish tropical ecosystem with a history of massive anthropogenic impacts, and a largely unknown sediment microbial diversity. Methanogens (e.g. Methanosarcinales, Methanomicrobiales) were more abundant at 1 mbsf, while sulphate-reducing microbes (Desulfurococcales, Thermoprotales, and Sulfolobales) were more abundant at deeper layers (4 mbsf; corresponding to 3 K Radiocarbon years before present, Holocene Epoch). Taxonomic analyzes and functional gene identification associated with anaerobic methane oxidation (e.g. monomethylamine methyltransferase (mtmB), trimethylamine methyltransferase (mttB) and CO dehydrogenase/acetyl-CoA synthase delta subunit) and sulfate reduction indicated the dominance of Campylobacteria (Sulfurimonas) at deeper sediment layers. Gene sequences related to assimilation of inorganic sulfur increased with depth, while organic sulfur related sequences decrease, accompanying the clear reduction in the concentration of sulfur, organic carbon and chla torwards deeper layers. Analyzes of metagenome assembled genomes also led to the discovery of a novel order within the phylum Acidobacteriota, named Guanabacteria. This novel order had several in silico phenotyping features that differentiate it from closely related phylogenetic neighbors (e.g. Acidobacteria, Aminicenantes, and Thermoanaerobaculum), including several genes (carbon monoxide dehydrogenase, CO dehydrogenase/CO-methylating acetyl-CoA synthase complex subunit beta, heterodisulfide reductase, sulfite exporter TauE/SafE family protein, sulfurtransferase) that relevant for the S and C cycles. Furthermore, the recovered Bathyarchaeota genome SS9 illustrates the methanogenic potential in deeper sediment layer.
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Affiliation(s)
- Diogo A Tschoeke
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Núcleo Professor Rogerio Valle de Produção Sustentável-SAGE/COPPE, Centro de Gestão Tecnológica-CT2, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Programa de Engenharia Biomédica, COPPE, CT, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil.
| | - Felipe H Coutinho
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, Alicante, Spain
| | - Luciana Leomil
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Núcleo Professor Rogerio Valle de Produção Sustentável-SAGE/COPPE, Centro de Gestão Tecnológica-CT2, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Giselle Cavalcanti
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Núcleo Professor Rogerio Valle de Produção Sustentável-SAGE/COPPE, Centro de Gestão Tecnológica-CT2, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Bruno S Silva
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Núcleo Professor Rogerio Valle de Produção Sustentável-SAGE/COPPE, Centro de Gestão Tecnológica-CT2, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Gizele D Garcia
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Universidade Federal do Rio de Janeiro (UFRJ), Departamento de Ensino de Graduação, Campus UFRJ - Macaé Professor Aloisio Teixeira, Macaé, RJ, Brazil
| | - Leandro Candeia Dos Anjos
- Programa de Geoquímica, Departamento de Geoquímica, Instituto de Química, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Larissa Borges Nascimento
- Programa de Geoquímica, Departamento de Geoquímica, Instituto de Química, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Luciane S Moreira
- Programa de Geoquímica, Departamento de Geoquímica, Instituto de Química, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Koko Otsuki
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Núcleo Professor Rogerio Valle de Produção Sustentável-SAGE/COPPE, Centro de Gestão Tecnológica-CT2, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Renato C Cordeiro
- Programa de Geoquímica, Departamento de Geoquímica, Instituto de Química, Universidade Federal Fluminense, Niterói, RJ, Brazil
| | - Carlos E Rezende
- Laboratório de Ciências Ambientais, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, UENF, RJ, Brazil
| | - Fabiano L Thompson
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Núcleo Professor Rogerio Valle de Produção Sustentável-SAGE/COPPE, Centro de Gestão Tecnológica-CT2, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Cristiane C Thompson
- Laboratório de Microbiologia, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil; Núcleo Professor Rogerio Valle de Produção Sustentável-SAGE/COPPE, Centro de Gestão Tecnológica-CT2, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil.
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207
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Zhang CJ, Pan J, Liu Y, Duan CH, Li M. Genomic and transcriptomic insights into methanogenesis potential of novel methanogens from mangrove sediments. MICROBIOME 2020; 8:94. [PMID: 32552798 PMCID: PMC7302380 DOI: 10.1186/s40168-020-00876-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 05/26/2020] [Indexed: 05/19/2023]
Abstract
BACKGROUND Methanogens are crucial to global methane budget and carbon cycling. Methanogens from the phylum Euryarchaeota are currently classified into one class and seven orders, including two novel methanogen taxa, Methanofastidiosa and Methanomassiliicoccales. The relative importance of the novel methanogens to methane production in the natural environment is poorly understood. RESULTS Here, we used a combined metagenomic and metatranscriptomic approach to investigate the metabolic activity of methanogens in mangrove sediments in Futian Nature Reserve, Shenzhen. We obtained 13 metagenome-assembled genomes (MAGs) representing one class (Methanofastidiosa) and five orders (Methanomassiliicoccales, Methanomicrobiales, Methanobacteriales, Methanocellales, and Methanosarcinales) of methanogens, including the two novel methanogens. Comprehensive annotation indicated the presence of an H2-dependent methylotrophic methanogenesis pathway in Methanofastidiosa and Methanomassiliicoccales. Based on the functional gene analysis, hydrogenotrophic and methylotrophic methanogenesis are the dominant pathways in mangrove sediments. MAG mapping revealed that hydrogenotrophic Methanomicrobiales were the most abundant methanogens and that methylotrophic Methanomassiliicoccales were the most active methanogens in the analyzed sediment profile, suggesting their important roles in methane production. CONCLUSIONS Partial or near-complete genomes of two novel methanogen taxa, Methanofastidiosa and Methanomassiliicoccales, in natural environments were recovered and analyzed here for the first time. The presented findings highlight the ecological importance of the two novel methanogens and complement knowledge of how methane is produced in mangrove ecosystem. This study implies that two novel methanogens play a vital role in carbon cycle. Video Abstract.
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Affiliation(s)
- Cui-Jing Zhang
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, China
| | - Jie Pan
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Yang Liu
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Chang-Hai Duan
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Meng Li
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China.
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208
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Wei Y, Wachemo AC, Yuan H, Li X. Enhanced hydrolysis and acidification strategy for efficient co-digestion of pretreated corn stover with chicken manure: Digestion performance and microbial community structure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 720:137401. [PMID: 32325556 DOI: 10.1016/j.scitotenv.2020.137401] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/01/2020] [Accepted: 02/16/2020] [Indexed: 06/11/2023]
Abstract
The effect of enhanced hydrolysis and acidification (EHA) strategy on co-digestion performance of pretreated corn stover (CS) with chicken manure (CM) was investigated. The EHA process was applied to the CS pretreated with KOH and liquid fraction of digestate (LFD), prior to anaerobic digestion. The results showed that the efficiencies of hydrolysis and acidification for the pretreated CS group were significantly higher than the CS group. The maximum cumulative biomethane yield of 240.5 mL·gVS-1 and 242.0 mL·gVS-1 were obtained for the KOH CS group and LFD CS group during the EHA process at 1 day, showing 26.6% and 27.4% improvement over that of the control, respectively. T90 was shortened by 38.2%-44.1% and 17.7%-38.2%, correspondingly. The synergistic effects and hydrolysis kinetics were also enhanced by the EHA process. The communities of bacteria (Firmicutes, Proteobacteria, and Bacteroidetes) and archaea (Methanosaeta, Methanobacterium, and Methanosarcina) were enriched by the EHA process, and their interactions contributed to the improved digestion performance. Therefore, the EHA process was recommended for efficient biomethane conversion in co-digestion of CS and CM.
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Affiliation(s)
- Yufang Wei
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing 100029, PR China
| | - Akiber Chufo Wachemo
- Faculty of Water Supply and Environmental Engineering, Arba Minch University, P.O. Box 21, Arba Minch, Ethiopia
| | - HaiRong Yuan
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing 100029, PR China.
| | - XiuJin Li
- Department of Environmental Science and Engineering, Beijing University of Chemical Technology, 15 Beisanhuan East Road, Chaoyang District, Beijing 100029, PR China.
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209
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Wang Y, Wegener G, Ruff SE, Wang F. Methyl/alkyl-coenzyme M reductase-based anaerobic alkane oxidation in archaea. Environ Microbiol 2020; 23:530-541. [PMID: 32367670 DOI: 10.1111/1462-2920.15057] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 04/28/2020] [Accepted: 04/30/2020] [Indexed: 02/04/2023]
Abstract
Methyl-coenzyme M reductase (MCR) has been originally identified to catalyse the final step of the methanogenesis pathway. About 20 years ago anaerobic methane-oxidizing archaea (ANME) were discovered that use MCR enzymes to activate methane. ANME thrive at the thermodynamic limit of life, are slow-growing, and in most cases form syntrophic consortia with sulfate-reducing bacteria. Recently, archaea that have the ability to anaerobically oxidize non-methane multi-carbon alkanes such as ethane and n-butane were described in both enrichment cultures and environmental samples. These anaerobic multi-carbon alkane-oxidizing archaea (ANKA) use enzymes homologous to MCR named alkyl-coenzyme M reductase (ACR). Here we review the recent progresses on the diversity, distribution and functioning of both ANME and ANKA by presenting a detailed MCR/ACR-based phylogeny, compare their metabolic pathways and discuss the gaps in our knowledge of physiology of these organisms. To improve our understanding of alkane oxidation in archaea, we identified three directions for future research: (i) expanding cultivation attempts to validate omics-based metabolic models of yet-uncultured organisms, (ii) performing biochemical and structural analyses of key enzymes to understand thermodynamic and steric constraints and (iii) investigating the evolution of anaerobic alkane metabolisms and their impact on biogeochemical cycles.
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Affiliation(s)
- Yinzhao Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Gunter Wegener
- Max Planck Institute for Marine Microbiology, Bremen, Germany.,MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - S Emil Ruff
- Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA, USA.,J. Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, USA
| | - Fengping Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.,School of Oceanography, Shanghai Jiao Tong University, Shanghai, 200240, China.,Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, Guangdong, China
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210
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Diversity, ecology and evolution of Archaea. Nat Microbiol 2020; 5:887-900. [PMID: 32367054 DOI: 10.1038/s41564-020-0715-z] [Citation(s) in RCA: 202] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 03/30/2020] [Indexed: 12/23/2022]
Abstract
Compared to bacteria, our knowledge of archaeal biology is limited. Historically, microbiologists have mostly relied on culturing and single-gene diversity surveys to understand Archaea in nature. However, only six of the 27 currently proposed archaeal phyla have cultured representatives. Advances in genomic sequencing and computational approaches are revolutionizing our understanding of Archaea. The recovery of genomes belonging to uncultured groups from the environment has resulted in the description of several new phyla, many of which are globally distributed and are among the predominant organisms on the planet. In this Review, we discuss how these genomes, together with long-term enrichment studies and elegant in situ measurements, are providing insights into the metabolic capabilities of the Archaea. We also debate how such studies reveal how important Archaea are in mediating an array of ecological processes, including global carbon and nutrient cycles, and how this increase in archaeal diversity has expanded our view of the tree of life and early archaeal evolution, and has provided new insights into the origin of eukaryotes.
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211
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Cavalier-Smith T, Chao EEY. Multidomain ribosomal protein trees and the planctobacterial origin of neomura (eukaryotes, archaebacteria). PROTOPLASMA 2020. [PMID: 31900730 DOI: 10.1007/s00709-019-01442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Palaeontologically, eubacteria are > 3× older than neomura (eukaryotes, archaebacteria). Cell biology contrasts ancestral eubacterial murein peptidoglycan walls and derived neomuran N-linked glycoprotein coats/walls. Misinterpreting long stems connecting clade neomura to eubacteria on ribosomal sequence trees (plus misinterpreted protein paralogue trees) obscured this historical pattern. Universal multiprotein ribosomal protein (RP) trees, more accurate than rRNA trees, are taxonomically undersampled. To reduce contradictions with genically richer eukaryote trees and improve eubacterial phylogeny, we constructed site-heterogeneous and maximum-likelihood universal three-domain, two-domain, and single-domain trees for 143 eukaryotes (branching now congruent with 187-protein trees), 60 archaebacteria, and 151 taxonomically representative eubacteria, using 51 and 26 RPs. Site-heterogeneous trees greatly improve eubacterial phylogeny and higher classification, e.g. showing gracilicute monophyly, that many 'rDNA-phyla' belong in Proteobacteria, and reveal robust new phyla Synthermota and Aquithermota. Monoderm Posibacteria and Mollicutes (two separate wall losses) are both polyphyletic: multiple outer membrane losses in Endobacteria occurred separately from Actinobacteria; neither phylum is related to Chloroflexi, the most divergent prokaryotes, which originated photosynthesis (new model proposed). RP trees support an eozoan root for eukaryotes and are consistent with archaebacteria being their sisters and rooted between Filarchaeota (=Proteoarchaeota, including 'Asgardia') and Euryarchaeota sensu-lato (including ultrasimplified 'DPANN' whose long branches often distort trees). Two-domain trees group eukaryotes within Planctobacteria, and archaebacteria with Planctobacteria/Sphingobacteria. Integrated molecular/palaeontological evidence favours negibacterial ancestors for neomura and all life. Unique presence of key pre-neomuran characters favours Planctobacteria only as ancestral to neomura, which apparently arose by coevolutionary repercussions (explained here in detail, including RP replacement) of simultaneous outer membrane and murein loss. Planctobacterial C-1 methanotrophic enzymes are likely ancestral to archaebacterial methanogenesis and β-propeller-α-solenoid proteins to eukaryotic vesicle coats, nuclear-pore-complexes, and intraciliary transport. Planctobacterial chaperone-independent 4/5-protofilament microtubules and MamK actin-ancestors prepared for eukaryote intracellular motility, mitosis, cytokinesis, and phagocytosis. We refute numerous wrong ideas about the universal tree.
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Affiliation(s)
| | - Ema E-Yung Chao
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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212
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Cavalier-Smith T, Chao EEY. Multidomain ribosomal protein trees and the planctobacterial origin of neomura (eukaryotes, archaebacteria). PROTOPLASMA 2020; 257:621-753. [PMID: 31900730 PMCID: PMC7203096 DOI: 10.1007/s00709-019-01442-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 09/19/2019] [Indexed: 05/02/2023]
Abstract
Palaeontologically, eubacteria are > 3× older than neomura (eukaryotes, archaebacteria). Cell biology contrasts ancestral eubacterial murein peptidoglycan walls and derived neomuran N-linked glycoprotein coats/walls. Misinterpreting long stems connecting clade neomura to eubacteria on ribosomal sequence trees (plus misinterpreted protein paralogue trees) obscured this historical pattern. Universal multiprotein ribosomal protein (RP) trees, more accurate than rRNA trees, are taxonomically undersampled. To reduce contradictions with genically richer eukaryote trees and improve eubacterial phylogeny, we constructed site-heterogeneous and maximum-likelihood universal three-domain, two-domain, and single-domain trees for 143 eukaryotes (branching now congruent with 187-protein trees), 60 archaebacteria, and 151 taxonomically representative eubacteria, using 51 and 26 RPs. Site-heterogeneous trees greatly improve eubacterial phylogeny and higher classification, e.g. showing gracilicute monophyly, that many 'rDNA-phyla' belong in Proteobacteria, and reveal robust new phyla Synthermota and Aquithermota. Monoderm Posibacteria and Mollicutes (two separate wall losses) are both polyphyletic: multiple outer membrane losses in Endobacteria occurred separately from Actinobacteria; neither phylum is related to Chloroflexi, the most divergent prokaryotes, which originated photosynthesis (new model proposed). RP trees support an eozoan root for eukaryotes and are consistent with archaebacteria being their sisters and rooted between Filarchaeota (=Proteoarchaeota, including 'Asgardia') and Euryarchaeota sensu-lato (including ultrasimplified 'DPANN' whose long branches often distort trees). Two-domain trees group eukaryotes within Planctobacteria, and archaebacteria with Planctobacteria/Sphingobacteria. Integrated molecular/palaeontological evidence favours negibacterial ancestors for neomura and all life. Unique presence of key pre-neomuran characters favours Planctobacteria only as ancestral to neomura, which apparently arose by coevolutionary repercussions (explained here in detail, including RP replacement) of simultaneous outer membrane and murein loss. Planctobacterial C-1 methanotrophic enzymes are likely ancestral to archaebacterial methanogenesis and β-propeller-α-solenoid proteins to eukaryotic vesicle coats, nuclear-pore-complexes, and intraciliary transport. Planctobacterial chaperone-independent 4/5-protofilament microtubules and MamK actin-ancestors prepared for eukaryote intracellular motility, mitosis, cytokinesis, and phagocytosis. We refute numerous wrong ideas about the universal tree.
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Affiliation(s)
| | - Ema E-Yung Chao
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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213
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Xueping C, Juan Y, Zheng C, Hongmei Z, Wangda C, Fayan B, Yu Z, Imran Ahamed K, Chiquan H, Xiaoyan L. Acetotrophic methanogens are sensitive to long-term nickel contamination in paddy soil. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:1014-1025. [PMID: 32096538 DOI: 10.1039/d0em00029a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Paddy soil accounts for approximately one-fifth of the world's cultivated area and faces a serious threat from nickel (Ni). Ni pollution has an impact on the activity, composition and emission of methanogens in paddy, which is a major natural source of methane (CH4) emissions. We combined a high-throughput sequencing approach and laboratory incubation methods to evaluate the impact of long-term Ni pollution on the methanogenic archaeal community in paddy soil. The highest rate of CH4 production was 697 mg kg-1 of dry soil per d with the addition of sodium acetate at 50 mg kg-1 of Ni, which was significantly negatively correlated with the total and available Ni (p < 0.05). While the highest CH4 production rates were 485 and 544 mg kg-1 of dry soil per d with the addition of sodium formate and methanol, respectively, there was no significant difference in the CH4 production rate and maximum CH4 accumulation between the different Ni additions. Heavy pollution with 500 mg kg-1 of Ni unexceptionally inhibited the relative abundance of various genera of methanogens (22.2% in total). The abundance of acetotrophic Methanosaeta decreased with an increasing concentration of Ni (3.25-1.11%). The diverse nutrient types of species belonging to Methanosarcina were the highest under treatment with Ni200 (18.0%), and lowest in the soil with 500 mg kg-1 of Ni (2.8%). Similarly, the abundances of the most abundant hydrogenotrophic methanogens of Methanocellales were relatively high with Ni200 (26.2%) compared with those with Ni500 (5.4%). The mcrA gene was enriched under the light pollution treatment (50 mg kg-1 of Ni, 6.73 × 107 ± 9.0 × 106 copies per g of soil) compared with the control (4.18 × 107 ± 5.1 × 106 copies per g of soil). These results indicate that the long-term pollution by Ni has an impact on the activity and composition of methanogens with heavy Ni pollution, and in particular, acetotrophic methanogens are sensitive to Ni pollution in paddy soil.
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Affiliation(s)
- Chen Xueping
- S, chool of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
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214
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Finn DR, Ziv-El M, van Haren J, Park JG, Del Aguila-Pasquel J, Urquiza-Muñoz JD, Cadillo-Quiroz H. Methanogens and Methanotrophs Show Nutrient-Dependent Community Assemblage Patterns Across Tropical Peatlands of the Pastaza-Marañón Basin, Peruvian Amazonia. Front Microbiol 2020; 11:746. [PMID: 32390985 PMCID: PMC7193774 DOI: 10.3389/fmicb.2020.00746] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 03/30/2020] [Indexed: 11/17/2022] Open
Abstract
Tropical peatlands are globally important carbon reservoirs that play a crucial role in fluxes of atmospheric greenhouse gases. Amazon peatlands are expected to be large source of atmospheric methane (CH4) emissions, however little is understood about the rates of CH4 flux or the microorganisms that mediate it in these environments. Here we studied a mineral nutrient gradient across peatlands in the Pastaza-Marañón Basin, the largest tropical peatland in South America, to describe CH4 fluxes and environmental factors that regulate species assemblages of methanogenic and methanotrophic microorganisms. Peatlands were grouped as minerotrophic, mixed and ombrotrophic categories by their general water source leading to different mineral nutrient content (rich, mixed and poor) quantified by trace elements abundance. Microbial communities clustered dependent on nutrient content (ANOSIM p < 0.001). Higher CH4 flux was associated with minerotrophic communities compared to the other categories. The most dominant methanogens and methanotrophs were represented by Methanobacteriaceae, and Methylocystaceae, respectively. Weighted network analysis demonstrated tight clustering of most methanogen families with minerotrophic-associated microbial families. Populations of Methylocystaceae were present across all peatlands. Null model testing for species assemblage patterns and species rank distributions confirmed non-random aggregations of Methylococcacae methanotroph and methanogen families (p < 0.05). We conclude that in studied amazon peatlands increasing mineral nutrient content provides favorable habitats for Methanobacteriaceae, while Methylocystaceae populations seem to broadly distribute independent of nutrient content.
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Affiliation(s)
- Damien Robert Finn
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Michal Ziv-El
- School of Life Sciences, Arizona State University, Tempe, AZ, United States.,Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Joost van Haren
- Biosphere 2, University of Arizona, Tucson, AZ, United States
| | - Jin Gyoon Park
- Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | | | - Jose David Urquiza-Muñoz
- Laboratorio de Suelos del Centro de Investigaciones de Recursos Naturales de la Amazonia Peruana, and Facultad de Ciencias Forestales, Universidad de la Amazonia Peruana, Iquitos, Peru
| | - Hinsby Cadillo-Quiroz
- School of Life Sciences, Arizona State University, Tempe, AZ, United States.,Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, Tempe, AZ, United States.,Center for Fundamental and Applied Microbiomics, Biodesign Institute, Arizona State University, Tempe, AZ, United States
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215
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Compte-Port S, Fillol M, Gich F, Borrego CM. Metabolic versatility of freshwater sedimentary archaea feeding on different organic carbon sources. PLoS One 2020; 15:e0231238. [PMID: 32267873 PMCID: PMC7141681 DOI: 10.1371/journal.pone.0231238] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/19/2020] [Indexed: 12/25/2022] Open
Abstract
Members of the phylum Bathyarchaeota and the class Thermoplasmata are widespread in marine and freshwater sediments where they have been recognized as key players in the carbon cycle. Here, we tested the responsiveness of archaeal communities on settled plant debris and sediment from a karstic lake to different organic carbon amendments (amino acids, plant-derived carbohydrates, and aromatics) using a lab-scale microcosm. Changes in the composition and abundance of sediment and biofilm archaeal communities in both DNA and RNA fractions were assessed by 16S rRNA gene amplicon sequencing and qPCR, respectively, after 7 and 30 days of incubation. Archaeal communities showed compositional changes in terms of alpha and beta diversity in relation to the type of carbon source (amino acids vs. plant-derived compounds), the nucleic acid fraction (DNA vs. RNA), and the incubation time (7 vs. 30 days). Distinct groups within the Bathyarchaeota (Bathy-15 and Bathy-6) and the Thermoplasmata (MBG-D) differently reacted to carbon supplements as deduced from the analysis of RNA libraries. Whereas Bathyarchaeota in biofilms showed a long-term positive response to humic acids, their counterparts in the sediment were mainly stimulated by the addition of tryptophan, suggesting the presence of different subpopulations in both habitats. Overall, our work presents an in vitro assessment of the versatility of archaea inhabiting freshwater sediments towards organic carbon and introduces settled leaf litter as a new habitat for the Bathyarchaeota and the Thermoplasmata.
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Affiliation(s)
- Sergi Compte-Port
- Water Quality and Microbial Diversity, Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, Girona, Spain
| | - Mireia Fillol
- Water Quality and Microbial Diversity, Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, Girona, Spain
| | - Frederic Gich
- Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, Girona, Spain
| | - Carles M. Borrego
- Water Quality and Microbial Diversity, Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, Girona, Spain
- Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, Girona, Spain
- * E-mail:
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216
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Sun Y, Liu Y, Pan J, Wang F, Li M. Perspectives on Cultivation Strategies of Archaea. MICROBIAL ECOLOGY 2020; 79:770-784. [PMID: 31432245 DOI: 10.1007/s00248-019-01422-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
Archaea have been recognized as a major domain of life since the 1970s and occupy a key position in the tree of life. Recent advances in culture-independent approaches have greatly accelerated the research son Archaea. However, many hypotheses concerning the diversity, physiology, and evolution of archaea are waiting to be confirmed by culture-base experiments. Consequently, archaeal isolates are in great demand. On the other hand, traditional approaches of archaeal cultivation are rarely successful and require urgent improvement. Here, we review the current practices and applicable microbial cultivation techniques, to inform on potential strategies that could improve archaeal cultivation in the future. We first summarize the current knowledge on archaeal diversity, with an emphasis on cultivated and uncultivated lineages pertinent to future research. Possible causes for the low success rate of the current cultivation practices are then discussed to propose future improvements. Finally, innovative insights for archaeal cultivation are described, including (1) medium refinement for selective cultivation based on the genetic and transcriptional information; (2) consideration of the up-to-date archaeal culturing skills; and (3) application of multiple cultivation techniques, such as co-culture, direct interspecies electron transfer (DIET), single-cell isolation, high-throughput culturing (HTC), and simulation of the natural habitat. Improved cultivation efforts should allow successful isolation of as yet uncultured archaea, contributing to the much-needed physiological investigation of archaea.
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Affiliation(s)
- Yihua Sun
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Yang Liu
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Jie Pan
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China
| | - Fengping Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China
- State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Meng Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, People's Republic of China.
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217
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Pan J, Zhou Z, Béjà O, Cai M, Yang Y, Liu Y, Gu JD, Li M. Genomic and transcriptomic evidence of light-sensing, porphyrin biosynthesis, Calvin-Benson-Bassham cycle, and urea production in Bathyarchaeota. MICROBIOME 2020; 8:43. [PMID: 32234071 PMCID: PMC7110647 DOI: 10.1186/s40168-020-00820-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 03/02/2020] [Indexed: 05/19/2023]
Abstract
BACKGROUND Bathyarchaeota, a newly proposed archaeal phylum, is considered as an important driver of the global carbon cycle. However, due to the great diversity of them, there is limited genomic information that accurately encompasses the metabolic potential of the entire archaeal phylum. RESULTS In the current study, nine metagenome-assembled genomes of Bathyarchaeota from four subgroups were constructed from mangrove sediments, and metatranscriptomes were obtained for evaluating their in situ transcriptional activities. Comparative analyses with reference genomes and the transcripts of functional genes posit an expanded role for Bathyarchaeota in phototrophy, autotrophy, and nitrogen and sulfur cycles, respectively. Notably, the presence of genes for rhodopsins, cobalamin biosynthesis, and the oxygen-dependent metabolic pathways in some Bathyarchaeota subgroup 6 genomes suggest a light-sensing and microoxic lifestyle within this subgroup. CONCLUSIONS The results of this study expand our knowledge of metabolic abilities and diverse lifestyles of Bathyarchaeota, highlighting the crucial role of Bathyarchaeota in geochemical cycle. Video abstract.
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Affiliation(s)
- Jie Pan
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Zhichao Zhou
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR China
| | - Oded Béjà
- Faculty of Biology, Technion-Israel Institute of Technology, 32000 Haifa, Israel
| | - Mingwei Cai
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Yuchun Yang
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR China
| | - Yang Liu
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Ji-Dong Gu
- Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR China
| | - Meng Li
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
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218
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Abstract
Current understanding of the diversity, biology, and ecology of Archaea is very limited, especially considering how few of the known phyla have been cultured or genomically explored. The reconstruction of “Ca. Methanomixophus” MAGs not only expands the known range of metabolic versatility of the members of Archaeoglobi but also suggests that the phylogenetic distribution of MCR and MTR complexes is even wider than previously anticipated. Euryarchaeal lineages have been believed to have a methanogenic last common ancestor. However, members of euryarchaeal Archaeoglobi have long been considered nonmethanogenic and their evolutionary history remains elusive. Here, three high-quality metagenomic-assembled genomes (MAGs) retrieved from high-temperature oil reservoir and hot springs, together with three newly assembled Archaeoglobi MAGs from previously reported hot spring metagenomes, are demonstrated to represent a novel genus of Archaeoglobaceae, “Candidatus Methanomixophus.” All “Ca. Methanomixophus” MAGs encode an M methyltransferase (MTR) complex and a traditional type of methyl-coenzyme M reductase (MCR) complex, which is different from the divergent MCR complexes found in “Ca. Polytropus marinifundus.” In addition, “Ca. Methanomixophus dualitatem” MAGs preserve the genomic capacity for dissimilatory sulfate reduction. Comparative phylogenetic analysis supports a laterally transferred origin for an MCR complex and vertical heritage of the MTR complex in this lineage. Metatranscriptomic analysis revealed concomitant in situ activity of hydrogen-dependent methylotrophic methanogenesis and heterotrophic fermentation within populations of “Ca. Methanomixophus hydrogenotrophicum” in a high-temperature oil reservoir. IMPORTANCE Current understanding of the diversity, biology, and ecology of Archaea is very limited, especially considering how few of the known phyla have been cultured or genomically explored. The reconstruction of “Ca. Methanomixophus” MAGs not only expands the known range of metabolic versatility of the members of Archaeoglobi but also suggests that the phylogenetic distribution of MCR and MTR complexes is even wider than previously anticipated.
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219
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Zou D, Pan J, Liu Z, Zhang C, Liu H, Li M. The Distribution of Bathyarchaeota in Surface Sediments of the Pearl River Estuary Along Salinity Gradient. Front Microbiol 2020; 11:285. [PMID: 32174899 PMCID: PMC7056671 DOI: 10.3389/fmicb.2020.00285] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 02/07/2020] [Indexed: 01/05/2023] Open
Abstract
Bathyarchaeota, a recently proposed archaeal phylum, is globally distributed and highly abundant in anoxic sediments. Metabolic pathways of the Bathyarchaeota members are diverse and, hence, this phylum has been proposed to play an important role in global biogeochemical cycles. Bathyarchaeota members are distributed in the estuarine environments. However, limited information is available about their detailed community structure, abundance, and functions in the Pearl River estuary (PRE). In the current study, we performed a comprehensive investigation of the archaeal community in the PRE surface sediments along a salinity gradient, with a focus on Bathyarchaeota. Bathyarchaeota was the dominant archaeal phylum, with the abundance of the bathyarchaeotal 16S rRNA gene ranging from 1.43 × 108 to 1.22 × 109 copies/g sediment dry weight (d.w.), and Bathy-8 was the dominant subgroup. Thaumarchaeota, Lokiarchaeota, and Euryarchaeota, including Thermoprofundales (MBG-D archaea), were the other major archaeal groups in the PRE. The differences of community distributions in the high- and low-salinity sediments were hence investigated. Statistical analysis revealed that besides salinity, ammonium, and total organic carbon were the most important environmental factors influencing the archaea community structure, including that of Bathyarchaeota, in the PRE. The archaeal network indicated the cooccurrence among Bathyarchaeota, Lokiarchaeota, and Euryarchaeota, while Bathy-6 presented unique correlations compared with other bathyarchaeotal subgroups. These observations indicate that Bathyarchaeota may play a role in ecosystem function through microbe-microbe interactions, revealing a possible different lifestyle for Bathy-6 in eutrophic estuarine sediments.
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Affiliation(s)
- Dayu Zou
- SZU-HKUST Joint Ph.D. Program in Marine Environmental Science, Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Jie Pan
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Zongbao Liu
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Chuanlun Zhang
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Southern University of Science and Technology, Shenzhen, China
| | - Hongbin Liu
- Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Meng Li
- SZU-HKUST Joint Ph.D. Program in Marine Environmental Science, Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
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220
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Methylotrophic methanogens everywhere - physiology and ecology of novel players in global methane cycling. Biochem Soc Trans 2020; 47:1895-1907. [PMID: 31819955 DOI: 10.1042/bst20180565] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 01/14/2023]
Abstract
Research on methanogenic Archaea has experienced a revival, with many novel lineages of methanogens recently being found through cultivation and suggested via metagenomics approaches, respectively. Most of these lineages comprise Archaea (potentially) capable of methanogenesis from methylated compounds, a pathway that had previously received comparably little attention. In this review, we provide an overview of these new lineages with a focus on the Methanomassiliicoccales. These lack the Wood-Ljungdahl pathway and employ a hydrogen-dependent methylotrophic methanogenesis pathway fundamentally different from traditional methylotrophic methanogens. Several archaeal candidate lineages identified through metagenomics, such as the Ca. Verstraetearchaeota and Ca. Methanofastidiosa, encode genes for a methylotrophic methanogenesis pathway similar to the Methanomassiliicoccales. Thus, the latter are emerging as a model system for physiological, biochemical and ecological studies of hydrogen-dependent methylotrophic methanogens. Methanomassiliicoccales occur in a large variety of anoxic habitats including wetlands and animal intestinal tracts, i.e. in the major natural and anthropogenic sources of methane emissions, respectively. Especially in ruminant animals, they likely are among the major methane producers. Taken together, (hydrogen-dependent) methylotrophic methanogens are much more diverse and widespread than previously thought. Considering the role of methane as potent greenhouse gas, resolving the methanogenic nature of a broad range of putative novel methylotrophic methanogens and assessing their role in methane emitting environments are pressing issues for future research on methanogens.
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Metabolic potentials of archaeal lineages resolved from metagenomes of deep Costa Rica sediments. ISME JOURNAL 2020; 14:1345-1358. [PMID: 32066876 DOI: 10.1038/s41396-020-0615-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/30/2020] [Accepted: 02/07/2020] [Indexed: 02/06/2023]
Abstract
Numerous archaeal lineages are known to inhabit marine subsurface sediments, although their distributions, metabolic capacities, and interspecies interactions are still not well understood. Abundant and diverse archaea were recently reported in Costa Rica (CR) margin subseafloor sediments recovered during IODP Expedition 334. Here, we recover metagenome-assembled genomes (MAGs) of archaea from the CR margin and compare them to their relatives from shallower settings. We describe 31 MAGs of six different archaeal lineages (Lokiarchaeota, Thorarchaeota, Heimdallarchaeota, Bathyarcheota, Thermoplasmatales, and Hadesarchaea) and thoroughly analyze representative MAGs from the phyla Lokiarchaeota and Bathyarchaeota. Our analysis suggests the potential capability of Lokiarchaeota members to anaerobically degrade aliphatic and aromatic hydrocarbons. We show it is genetically possible and energetically feasible for Lokiarchaeota to degrade benzoate if they associate with organisms using nitrate, nitrite, and sulfite as electron acceptors, which suggests a possibility of syntrophic relationships between Lokiarchaeota and nitrite and sulfite reducing bacteria. The novel Bathyarchaeota lineage possesses an incomplete methanogenesis pathway lacking the methyl coenzyme M reductase complex and encodes a noncanonical acetogenic pathway potentially coupling methylotrophy to acetogenesis via the methyl branch of Wood-Ljungdahl pathway. These metabolic characteristics suggest the potential of this Bathyarchaeota lineage to be a transition between methanogenic and acetogenic Bathyarchaeota lineages. This work expands our knowledge about the metabolic functional repertoire of marine benthic archaea.
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Zhu X, Campanaro S, Treu L, Seshadri R, Ivanova N, Kougias PG, Kyrpides N, Angelidaki I. Metabolic dependencies govern microbial syntrophies during methanogenesis in an anaerobic digestion ecosystem. MICROBIOME 2020; 8:22. [PMID: 32061251 PMCID: PMC7024554 DOI: 10.1186/s40168-019-0780-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 12/27/2019] [Indexed: 05/03/2023]
Abstract
Methanogenesis, a biological process mediated by complex microbial communities, has attracted great attention due to its contribution to global warming and potential in biotechnological applications. The current study unveiled the core microbial methanogenic metabolisms in anaerobic vessel ecosystems by applying combined genome-centric metagenomics and metatranscriptomics. Here, we demonstrate that an enriched natural system, fueled only with acetate, could support a bacteria-dominated microbiota employing a multi-trophic methanogenic process. Moreover, significant changes, in terms of microbial structure and function, were recorded after the system was supplemented with additional H2. Methanosarcina thermophila, the predominant methanogen prior to H2 addition, simultaneously performed acetoclastic, hydrogenotrophic, and methylotrophic methanogenesis. The methanogenic pattern changed after the addition of H2, which immediately stimulated Methanomicrobia-activity and was followed by a slow enrichment of Methanobacteria members. Interestingly, the essential genes involved in the Wood-Ljungdahl pathway were not expressed in bacterial members. The high expression of a glycine cleavage system indicated the activation of alternative metabolic pathways for acetate metabolism, which were reconstructed in the most abundant bacterial genomes. Moreover, as evidenced by predicted auxotrophies, we propose that specific microbes of the community were forming symbiotic relationships, thus reducing the biosynthetic burden of individual members. These results provide new information that will facilitate future microbial ecology studies of interspecies competition and symbiosis in methanogenic niches. Video abstract.
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Affiliation(s)
- Xinyu Zhu
- Department of Environmental Engineering, Technical University of Denmark, Building 115, DK-2800, Kgs. Lyngby, Denmark
- US Department of Energy, Joint Genome Institute, Walnut Creek, CA, USA
| | - Stefano Campanaro
- Department of Biology, University of Padua, Via U. Bassi 58/b, 35121, Padua, Italy
- CRIBI Biotechnology Center, University of Padua, 35131, Padua, Italy
| | - Laura Treu
- Department of Environmental Engineering, Technical University of Denmark, Building 115, DK-2800, Kgs. Lyngby, Denmark.
- Department of Biology, University of Padua, Via U. Bassi 58/b, 35121, Padua, Italy.
| | - Rekha Seshadri
- US Department of Energy, Joint Genome Institute, Walnut Creek, CA, USA
| | - Natalia Ivanova
- US Department of Energy, Joint Genome Institute, Walnut Creek, CA, USA
| | - Panagiotis G Kougias
- Department of Environmental Engineering, Technical University of Denmark, Building 115, DK-2800, Kgs. Lyngby, Denmark.
- Soil and Water Resources Institute, Hellenic Organisation-DEMETER, 57001, Thermi-, Thessaloniki, Greece.
| | - Nikos Kyrpides
- US Department of Energy, Joint Genome Institute, Walnut Creek, CA, USA
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark, Building 115, DK-2800, Kgs. Lyngby, Denmark
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Wang W, Tao J, Liu H, Li P, Chen S, Wang P, Zhang C. Contrasting bacterial and archaeal distributions reflecting different geochemical processes in a sediment core from the Pearl River Estuary. AMB Express 2020; 10:16. [PMID: 31970539 PMCID: PMC6975606 DOI: 10.1186/s13568-020-0950-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 01/06/2020] [Indexed: 01/27/2023] Open
Abstract
Microbial community structure and metabolic activities have profound impacts on biogeochemical processes in marine sediments. Functional bacteria such as nitrate- and sulfate-reducing bacteria respond to redox gradients by coupling specific reactions amenable to relevant energy metabolisms. However, similar functional patterns have not been observed for sedimentary archaea (except for anaerobic methanotrophs and methanogens). We coupled taxonomic composition with comprehensive geochemical species to investigate the participation of distinct bacteria and archaea in sedimentary geochemical cycles in a sediment core (300 cm) from Pearl River Estuary (PRE). Geochemical properties (NO3−, dissolved Mn and Fe, SO42+, NH4+; dissolved inorganic carbon (DIC), δ13CDIC, dissolved organic carbon (DOC), total organic carbon (TOC), δ13CTOC, and fluorescent dissolved organic matter (FDOM)) exhibited strong depth variability of different trends. Bacterial 16S rRNA- and dsrB gene abundance decreased sharply with depth while archaeal and bathyarchaeotal 16S rRNA gene copies were relatively constant. This resulted in an increase in relative abundance of archaea from surface (11.6%) to bottom (42.8%). Network analysis showed that bacterial groups of Desulfobacterales, Syntrophobacterales and Gammaproteobacteria were significantly (P < 0.0001) associated with SO42− and dissolved Mn while archaeal groups of Bathyarchaeota, Group C3 and Marine Benthic Group D (MBGD) showed close positive correlations (P < 0.0001) with NH4+, δ13CTOC values and humic-like FDOM. Our study suggested that these bacterial groups dominated in redox processes relevant to sulfate or metal oxides, while the archaeal groups are more like to degrade recalcitrant organic compounds in anaerobic sediments.
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Posttranslational Methylation of Arginine in Methyl Coenzyme M Reductase Has a Profound Impact on both Methanogenesis and Growth of Methanococcus maripaludis. J Bacteriol 2020; 202:JB.00654-19. [PMID: 31740491 DOI: 10.1128/jb.00654-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 11/09/2019] [Indexed: 02/05/2023] Open
Abstract
Catalyzing the key step for anaerobic production and/or oxidation of methane and likely other short-chain alkanes, methyl coenzyme M reductase (Mcr) and its homologs play a key role in the global carbon cycle. The McrA subunit possesses up to five conserved posttranslational modifications (PTMs) at its active site. It was previously suggested that methanogenesis marker protein 10 (Mmp10) could play an important role in methanogenesis. To systematically examine its physiological role, mmpX (locus tag MMP1554), the gene encoding Mmp10 in Methanococcus maripaludis, was deleted with a new genetic tool, resulting in the complete loss of the 5-C-(S)-methylarginine PTM of residue 275 in the McrA subunit. When the ΔmmpX mutant was complemented with the wild-type gene expressed by either a strong or a weak promoter, methylation was fully restored. Compared to the parental strain, maximal rates of methane formation by whole cells were reduced by 40 to 60% in the ΔmmpX mutant. The reduction in activity was fully reversed by the complement with the strong promoter. Site-directed mutagenesis of mmpX resulted in a differential loss of arginine methylation among the mutants in vivo, suggesting that activities of Mmp10 directly modulated methylation. R275 was present in a highly conserved PXRR275(A/S)R(G/A) signature sequence in McrAs. The only other protein in M. maripaludis containing a similar sequence was not methylated, suggesting that Mmp10 is specific for McrA. In conclusion, Mmp10 modulates the methyl-Arg PTM on McrA in a highly specific manner, which has a profound impact on Mcr activity.IMPORTANCE Mcr is the key enzyme in methanogenesis and a promising candidate for bioengineering the conversion of methane to liquid fuel. Our knowledge of Mcr is still limited. In terms of complexity, uniqueness, and environmental importance, Mcr is more comparable to photosynthetic reaction centers than conventional enzymes. PTMs have long been hypothesized to play key roles in modulating Mcr activity. Here, we directly link the mmpX gene to the arginine PTM of Mcr, demonstrate its association with methanogenesis activity, and offer insights into its substrate specificity and putative cofactor binding sites. This is also the first time that a PTM of McrA has been shown to have a substantial impact on both methanogenesis and growth in the absence of additional stressors.
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Klasek S, Torres ME, Bartlett DH, Tyler M, Hong W, Colwell F. Microbial communities from Arctic marine sediments respond slowly to methane addition during
ex situ
enrichments. Environ Microbiol 2020; 22:1829-1846. [DOI: 10.1111/1462-2920.14895] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/11/2019] [Accepted: 11/30/2019] [Indexed: 11/27/2022]
Affiliation(s)
- Scott Klasek
- Department of Microbiology Oregon State University Corvallis Oregon USA
| | - Marta E. Torres
- College of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis Oregon USA
| | - Douglas H. Bartlett
- Marine Biology Research Division, Scripps Institution of Oceanography University of California San Diego California 92093‐0202 USA
| | - Madeline Tyler
- Department of Microbiology Oregon State University Corvallis Oregon USA
| | - Wei‐Li Hong
- Centre for Arctic Gas Hydrate, Environment and Climate (CAGE), Department of Geosciences UiT The Arctic University of Norway N‐9037 Tromsø Norway
| | - Frederick Colwell
- Department of Microbiology Oregon State University Corvallis Oregon USA
- College of Earth, Ocean, and Atmospheric Sciences Oregon State University Corvallis Oregon USA
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Genome- and Community-Level Interaction Insights into Carbon Utilization and Element Cycling Functions of Hydrothermarchaeota in Hydrothermal Sediment. mSystems 2020; 5:5/1/e00795-19. [PMID: 31911466 PMCID: PMC6946796 DOI: 10.1128/msystems.00795-19] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Hydrothermal vents release reduced compounds and small organic carbon compounds into the surrounding seawater, providing essential substrates for microbial growth and bioenergy transformations. Despite the wide distribution of the marine benthic group E archaea (referred to as Hydrothermarchaeota) in the hydrothermal environment, little is known about their genomic repertoires and biogeochemical significance. Here, we studied four highly complete (>80%) metagenome-assembled genomes (MAGs) from a black smoker chimney and the surrounding sulfur-rich sediments on the South Atlantic Mid-Ocean Ridge and publicly available data sets (the Integrated Microbial Genomes system of the U.S. Department of Energy-Joint Genome Institute and NCBI SRA data sets). Genomic analysis suggested a wide carbon metabolic diversity of Hydrothermarchaeota members, including the utilization of proteins, lactate, and acetate; the anaerobic degradation of aromatics; the oxidation of C1 compounds (CO, formate, and formaldehyde); the utilization of methyl compounds; CO2 incorporation by the tetrahydromethanopterin-based Wood-Ljungdahl pathway; and participation in the type III ribulose-1,5-bisphosphate carboxylase/oxygenase-based Calvin-Benson-Bassham cycle. These microbes also potentially oxidize sulfur, arsenic, and hydrogen and engage in anaerobic respiration based on sulfate reduction and denitrification. Among the 140 MAGs reconstructed from the black smoker chimney microbial community (including Hydrothermarchaeota MAGs), community-level metabolic predictions suggested a redundancy of carbon utilization and element cycling functions and interactive syntrophic and sequential utilization of substrates. These processes might make various carbon and energy sources widely accessible to the microorganisms. Further, the analysis suggested that Hydrothermarchaeota members contained important functional components obtained from the community via lateral gene transfer, becoming a distinctive clade. This might serve as a niche-adaptive strategy for metabolizing heavy metals, C1 compounds, and reduced sulfur compounds. Collectively, the analysis provides comprehensive metabolic insights into the Hydrothermarchaeota IMPORTANCE This study provides comprehensive metabolic insights into the Hydrothermarchaeota from comparative genomics, evolution, and community-level perspectives. Members of the Hydrothermarchaeota synergistically participate in a wide range of carbon-utilizing and element cycling processes with other microorganisms in the community. We expand the current understanding of community interactions within the hydrothermal sediment and chimney, suggesting that microbial interactions based on sequential substrate metabolism are essential to nutrient and element cycling.
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Campanaro S, Treu L, Rodriguez-R LM, Kovalovszki A, Ziels RM, Maus I, Zhu X, Kougias PG, Basile A, Luo G, Schlüter A, Konstantinidis KT, Angelidaki I. New insights from the biogas microbiome by comprehensive genome-resolved metagenomics of nearly 1600 species originating from multiple anaerobic digesters. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:25. [PMID: 32123542 PMCID: PMC7038595 DOI: 10.1186/s13068-020-01679-y] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/08/2020] [Indexed: 05/20/2023]
Abstract
BACKGROUND Microorganisms in biogas reactors are essential for degradation of organic matter and methane production. However, a comprehensive genome-centric comparison, including relevant metadata for each sample, is still needed to identify the globally distributed biogas community members and serve as a reliable repository. RESULTS Here, 134 publicly available metagenomes derived from different biogas reactors were used to recover 1635 metagenome-assembled genomes (MAGs) representing different biogas bacterial and archaeal species. All genomes were estimated to be > 50% complete and nearly half ≥ 90% complete with ≤ 5% contamination. In most samples, specialized microbial communities were established, while only a few taxa were widespread among the different reactor systems. Metabolic reconstruction of the MAGs enabled the prediction of functional traits related to biomass degradation and methane production from waste biomass. An extensive evaluation of the replication index provided an estimation of the growth dynamics for microbes involved in different steps of the food chain. CONCLUSIONS The outcome of this study highlights a high flexibility of the biogas microbiome, allowing it to modify its composition and to adapt to the environmental conditions, including temperatures and a wide range of substrates. Our findings enhance our mechanistic understanding of the AD microbiome and substantially extend the existing repository of genomes. The established database represents a relevant resource for future studies related to this engineered ecosystem.
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Affiliation(s)
- Stefano Campanaro
- Department of Biology, University of Padova, Via U. Bassi 58/b, 35121 Padua, Italy
- CRIBI Biotechnology Center, University of Padova, 35131 Padua, Italy
| | - Laura Treu
- Department of Biology, University of Padova, Via U. Bassi 58/b, 35121 Padua, Italy
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Luis M. Rodriguez-R
- School of Civil & Environmental Engineering and School of Biological Sciences (Adjunct), Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0512 USA
| | - Adam Kovalovszki
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Ryan M. Ziels
- Department of Civil Engineering, University of British Columbia, Vancouver, BC Canada
| | - Irena Maus
- Genome Research of Industrial Microorganisms, Center for Biotechnology (CeBiTec), Bielefeld University, Universitätsstr. 27, 33615 Bielefeld, Germany
| | - Xinyu Zhu
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Panagiotis G. Kougias
- Hellenic Agricultural Organization DEMETER, Soil and Water Resources Institute, Thermi-Thessaloniki, Greece
| | - Arianna Basile
- Department of Biology, University of Padova, Via U. Bassi 58/b, 35121 Padua, Italy
| | - Gang Luo
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433 China
| | - Andreas Schlüter
- Hellenic Agricultural Organization DEMETER, Soil and Water Resources Institute, Thermi-Thessaloniki, Greece
| | - Konstantinos T. Konstantinidis
- School of Civil & Environmental Engineering and School of Biological Sciences (Adjunct), Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0512 USA
| | - Irini Angelidaki
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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Rissanen AJ, Peura S, Mpamah PA, Taipale S, Tiirola M, Biasi C, Mäki A, Nykänen H. Vertical stratification of bacteria and archaea in sediments of a small boreal humic lake. FEMS Microbiol Lett 2019; 366:5365400. [PMID: 30806656 PMCID: PMC6476745 DOI: 10.1093/femsle/fnz044] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 02/23/2019] [Indexed: 01/22/2023] Open
Abstract
Although sediments of small boreal humic lakes are important carbon stores and greenhouse gas sources, the composition and structuring mechanisms of their microbial communities have remained understudied. We analyzed the vertical profiles of microbial biomass indicators (PLFAs, DNA and RNA) and the bacterial and archaeal community composition (sequencing of 16S rRNA gene amplicons and qPCR of mcrA) in sediment cores collected from a typical small boreal lake. While microbial biomass decreased with sediment depth, viable microbes (RNA and PLFA) were present all through the profiles. The vertical stratification patterns of the bacterial and archaeal communities resembled those in marine sediments with well-characterized groups (e.g. Methanomicrobia, Proteobacteria, Cyanobacteria, Bacteroidetes) dominating in the surface sediment and being replaced by poorly-known groups (e.g. Bathyarchaeota, Aminicenantes and Caldiserica) in the deeper layers. The results also suggested that, similar to marine systems, the deep bacterial and archaeal communities were predominantly assembled by selective survival of taxa able to persist in the low energy conditions. Methanotrophs were rare, further corroborating the role of these methanogen-rich sediments as important methane emitters. Based on their taxonomy, the deep-dwelling groups were putatively organo-heterotrophic, organo-autotrophic and/or acetogenic and thus may contribute to changes in the lake sediment carbon storage.
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Affiliation(s)
- Antti J Rissanen
- Tampere University, Faculty of Engineering and Natural Sciences, Korkeakoulunkatu 10, FI-33720, Tampere, Finland.,University of Jyväskylä, Department of Biological and Environmental Science, PO Box 35, FI-40014, Jyväskylä, Finland
| | - Sari Peura
- University of Jyväskylä, Department of Biological and Environmental Science, PO Box 35, FI-40014, Jyväskylä, Finland
| | - Promise A Mpamah
- University of Jyväskylä, Department of Biological and Environmental Science, PO Box 35, FI-40014, Jyväskylä, Finland
| | - Sami Taipale
- University of Jyväskylä, Department of Biological and Environmental Science, PO Box 35, FI-40014, Jyväskylä, Finland
| | - Marja Tiirola
- University of Jyväskylä, Department of Biological and Environmental Science, PO Box 35, FI-40014, Jyväskylä, Finland
| | - Christina Biasi
- University of Eastern Finland, Department of Environmental and Biological Sciences, PO Box 1627, FI-70211, Kuopio, Finland
| | - Anita Mäki
- University of Jyväskylä, Department of Biological and Environmental Science, PO Box 35, FI-40014, Jyväskylä, Finland
| | - Hannu Nykänen
- University of Eastern Finland, Department of Environmental and Biological Sciences, PO Box 1627, FI-70211, Kuopio, Finland
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Chen S, Wang P, Liu H, Xie W, Wan XS, Kao SJ, Phelps TJ, Zhang C. Population dynamics of methanogens and methanotrophs along the salinity gradient in Pearl River Estuary: implications for methane metabolism. Appl Microbiol Biotechnol 2019; 104:1331-1346. [DOI: 10.1007/s00253-019-10221-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 10/11/2019] [Accepted: 10/27/2019] [Indexed: 01/01/2023]
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Abstract
Understanding the sources and controls on microbial methane production from wetland soils is critical to global methane emission predictions, particularly in light of changing climatic conditions. Current biogeochemical models of methanogenesis consider only acetoclastic and hydrogenotrophic sources and exclude methylotrophic methanogenesis, potentially underestimating microbial contributions to methane flux. Our multi-omic results demonstrated that methylotrophic methanogens of the family Methanomassiliicoccaceae were present and active in a freshwater wetland, with metatranscripts indicating that methanol, not methylamines, was the likely substrate under the conditions measured here. However, laboratory experiments indicated the potential for other methanogens to become enriched in response to trimethylamine, revealing the reservoir of methylotrophic methanogenesis potential residing in these soils. Collectively, our approach used coupled field and laboratory investigations to illuminate metabolisms influencing the terrestrial microbial methane cycle, thereby offering direction for increased realism in predictive process-oriented models of methane flux in wetland soils. Wetland soils are one of the largest natural contributors to the emission of methane, a potent greenhouse gas. Currently, microbial contributions to methane emissions from these systems emphasize the roles of acetoclastic and hydrogenotrophic methanogens, while less frequently considering methyl-group substrates (e.g., methanol and methylamines). Here, we integrated laboratory and field experiments to explore the potential for methylotrophic methanogenesis in Old Woman Creek (OWC), a temperate freshwater wetland located in Ohio, USA. We first demonstrated the capacity for methylotrophic methanogenesis in these soils using laboratory soil microcosms amended with trimethylamine. However, subsequent field porewater nuclear magnetic resonance (NMR) analyses to identify methanogenic substrates failed to detect evidence for methylamine compounds in soil porewaters, instead noting the presence of the methylotrophic substrate methanol. Accordingly, our wetland soil-derived metatranscriptomic data indicated that methanol utilization by the Methanomassiliicoccaceae was the likely source of methylotrophic methanogenesis. Methanomassiliicoccaceae relative contributions to mcrA transcripts nearly doubled with depth, accounting for up to 8% of the mcrA transcripts in 25-cm-deep soils. Longitudinal 16S rRNA amplicon and mcrA gene surveys demonstrated that Methanomassiliicoccaceae were stably present over 2 years across lateral and depth gradients in this wetland. Meta-analysis of 16S rRNA sequences similar (>99%) to OWC Methanomassiliicoccaceae in public databases revealed a global distribution, with a high representation in terrestrial soils and sediments. Together, our results demonstrate that methylotrophic methanogenesis likely contributes to methane flux from climatically relevant wetland soils. IMPORTANCE Understanding the sources and controls on microbial methane production from wetland soils is critical to global methane emission predictions, particularly in light of changing climatic conditions. Current biogeochemical models of methanogenesis consider only acetoclastic and hydrogenotrophic sources and exclude methylotrophic methanogenesis, potentially underestimating microbial contributions to methane flux. Our multi-omic results demonstrated that methylotrophic methanogens of the family Methanomassiliicoccaceae were present and active in a freshwater wetland, with metatranscripts indicating that methanol, not methylamines, was the likely substrate under the conditions measured here. However, laboratory experiments indicated the potential for other methanogens to become enriched in response to trimethylamine, revealing the reservoir of methylotrophic methanogenesis potential residing in these soils. Collectively, our approach used coupled field and laboratory investigations to illuminate metabolisms influencing the terrestrial microbial methane cycle, thereby offering direction for increased realism in predictive process-oriented models of methane flux in wetland soils.
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231
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Han W, He P, Shao L, Lü F. Road to full bioconversion of biowaste to biochemicals centering on chain elongation: A mini review. J Environ Sci (China) 2019; 86:50-64. [PMID: 31787190 DOI: 10.1016/j.jes.2019.05.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 05/16/2019] [Accepted: 05/16/2019] [Indexed: 06/10/2023]
Abstract
Production of biochemicals from waste streams has been attracting increasing worldwide interest to achieve climate protection goals. Chain elongation (CE) for production of medium-chain carboxylic acids (MCCAs, especially caproate, enanthate and caprylate) from diverse biowaste has emerged as a potential economic and environmental technology for a sustainable society. The present mini review summarizes the research utilizing various synthetic or real waste-derived substrates available for MCCA production. Additionally, the microbial characteristics of the CE process are surveyed and discussed. Considering that a large proportion of recalcitrantly biodegradable biowaste and residues cannot be further utilized by CE systems and remain to be treated and disposed, we propose here a loop concept of bioconversion of biowaste to MCCAs making full use of the biowaste with zero emission. This could make possible an alternative technology for synthesis of value-added products from a wide range of biowaste, or even non-biodegradable waste (such as, plastics and rubbers). Meanwhile, the remaining scientific questions, unsolved problems, application potential and possible developments for this technology are discussed.
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Affiliation(s)
- Wenhao Han
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Pinjing He
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; 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 China (MOHURD), China
| | - Liming Shao
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; 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 China (MOHURD), China
| | - Fan Lü
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China; Institute of Waste Treatment and Reclamation, Tongji University, Shanghai 200092, China.
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Genomic and phenotypic insights point to diverse ecological strategies by facultative anaerobes obtained from subsurface coal seams. Sci Rep 2019; 9:16186. [PMID: 31700097 PMCID: PMC6838118 DOI: 10.1038/s41598-019-52846-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/04/2019] [Indexed: 02/07/2023] Open
Abstract
Microbes in subsurface coal seams are responsible for the conversion of the organic matter in coal to methane, resulting in vast reserves of coal seam gas. This process is important from both environmental and economic perspectives as coal seam gas is rapidly becoming a popular fuel source worldwide and is a less carbon intensive fuel than coal. Despite the importance of this process, little is known about the roles of individual bacterial taxa in the microbial communities carrying out this process. Of particular interest is the role of members of the genus Pseudomonas, a typically aerobic taxa which is ubiquitous in coal seam microbial communities worldwide and which has been shown to be abundant at early time points in studies of ecological succession on coal. The current study performed aerobic isolations of coal seam microbial taxa generating ten facultative anaerobic isolates from three coal seam formation waters across eastern Australia. Subsequent genomic sequencing and phenotypic analysis revealed a range of ecological strategies and roles for these facultative anaerobes in biomass recycling, suggesting that this group of organisms is involved in the degradation of accumulated biomass in coal seams, funnelling nutrients back into the microbial communities degrading coal to methane.
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Vigneron A, Cruaud P, Bhiry N, Lovejoy C, Vincent WF. Microbial Community Structure and Methane Cycling Potential along a Thermokarst Pond-Peatland Continuum. Microorganisms 2019; 7:microorganisms7110486. [PMID: 31652931 PMCID: PMC6920961 DOI: 10.3390/microorganisms7110486] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 01/08/2023] Open
Abstract
The thawing of ice-rich permafrost soils in northern peatlands leads to the formation of thermokarst ponds, surrounded by organic-rich soils. These aquatic ecosystems are sites of intense microbial activity, and CO2 and CH4 emissions. Many of the pond systems in northern landscapes and their surrounding peatlands are hydrologically contiguous, but little is known about the microbial connectivity of concentric habitats around the thermokarst ponds, or the effects of peat accumulation and infilling on the microbial communities. Here we investigated microbial community structure and abundance in a thermokarst pond-peatland system in subarctic Canada. Several lineages were ubiquitous, supporting a prokaryotic continuum from the thermokarst pond to surrounding peatlands. However, the microbial community structure shifted from typical aerobic freshwater microorganisms (Betaproteobacteria and Alphaproteobacteria) in the pond towards acidophilic and anaerobic lineages (Acidobacteria and Choroflexi) in the connected peatland waters, likely selected by the acidification of the water by Sphagnum mosses. Marked changes in abundance and community composition of methane cycling microorganisms were detected along the thermokarst pond-peatland transects, suggesting fine tuning of C-1 carbon cycling within a highly connected system, and warranting the need for higher spatial resolution across the thermokarst landscape to accurately predict net greenhouse gas emissions from northern peatlands.
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Affiliation(s)
- Adrien Vigneron
- Centre d'études Nordiques (CEN), Université Laval, Québec, QC G1V 0A6, Canada.
- Département de Biologie, Université Laval, Québec, QC G1V 0A6, Canada.
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC G1V 0A6, Canada.
- Takuvik Joint International Laboratory, Université Laval, Québec, QC G1V 0A6, Canada.
| | - Perrine Cruaud
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC G1V 0A6, Canada.
- Département de Biochimie, de Microbiologie et de Bio-informatique, Université Laval, Québec, QC G1V 0A6, Canada.
| | - Najat Bhiry
- Centre d'études Nordiques (CEN), Université Laval, Québec, QC G1V 0A6, Canada.
- Département de Géographie, Université Laval, Québec, QC G1V 0A6, Canada.
| | - Connie Lovejoy
- Centre d'études Nordiques (CEN), Université Laval, Québec, QC G1V 0A6, Canada.
- Département de Biologie, Université Laval, Québec, QC G1V 0A6, Canada.
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC G1V 0A6, Canada.
- Takuvik Joint International Laboratory, Université Laval, Québec, QC G1V 0A6, Canada.
| | - Warwick F Vincent
- Centre d'études Nordiques (CEN), Université Laval, Québec, QC G1V 0A6, Canada.
- Département de Biologie, Université Laval, Québec, QC G1V 0A6, Canada.
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC G1V 0A6, Canada.
- Takuvik Joint International Laboratory, Université Laval, Québec, QC G1V 0A6, Canada.
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234
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Yu T, Zhang M, Kang D, Zhao S, Ding A, Lin Q, Xu D, Hong Y, Wang L, Zheng P. Characteristics of Microbial Communities and Their Correlation With Environmental Substrates and Sediment Type in the Gas-Bearing Formation of Hangzhou Bay, China. Front Microbiol 2019; 10:2421. [PMID: 31708895 PMCID: PMC6819322 DOI: 10.3389/fmicb.2019.02421] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 10/07/2019] [Indexed: 12/02/2022] Open
Abstract
Shallow gas is a kind of natural gas buried in shallow strata, generally, with methane as the main component, endowing it a potential energy resource while also a potential risk to the safety of ground engineering and environment. Microbial activity is usually regarded as an important driving force to generate shallow gas via metabolizing the environmental substrates. Therefore, the research on the microbial communities will be helpful to reveal the distribution of shallow gas in the gas-bearing formation. In this study, 30 sediment samples below the seabed in Hangzhou Bay (China) from depths of 1.5 m to 55 m were collected to investigate their microbial community, environmental characteristics and sediment type (clay or sand). It turned out that the presence of shallow gas had a good correlation with the distribution of archaea rather than bacteria, with the dominant microbe of Bathyarchaeota, Thaumarchaeota, and Euryarchaeota in the formation. Methanosarcinaceae and ANME-1a with the capacity of methane metabolism occupied high proportions. The correlation analysis and redundancy analysis (RDA) suggested that ammonium was a key environmental substrate to indicate the microbial community in the formation. The sediment type was proposed to shape environmental substrates in the formation, thus further affecting the microbial communities. The clay strata were demonstrated to have an important role in the generation and distribution of shallow gas, and more attention should be paid in terms of its resource discovery and engineering safety assessment.
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Affiliation(s)
- Tao Yu
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Meng Zhang
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
- Advanced Environmental Biotechnology Centre, Nanyang Environment & Water Research Institute, Nanyang Technological University, Singapore, Singapore
| | - Da Kang
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Shuang Zhao
- Key Laboratory of Offshore Geotechnics and Material of Zhejiang Province, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, China
| | - Aqiang Ding
- Department of Environmental Science, College of Resources and Environmental Science, Chongqing University, Chongqing, China
| | - Qiujian Lin
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Dongdong Xu
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
| | - Yi Hong
- Key Laboratory of Offshore Geotechnics and Material of Zhejiang Province, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, China
| | - Lizhong Wang
- Key Laboratory of Offshore Geotechnics and Material of Zhejiang Province, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, China
| | - Ping Zheng
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, China
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235
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Hua ZS, Wang YL, Evans PN, Qu YN, Goh KM, Rao YZ, Qi YL, Li YX, Huang MJ, Jiao JY, Chen YT, Mao YP, Shu WS, Hozzein W, Hedlund BP, Tyson GW, Zhang T, Li WJ. Insights into the ecological roles and evolution of methyl-coenzyme M reductase-containing hot spring Archaea. Nat Commun 2019; 10:4574. [PMID: 31594929 PMCID: PMC6783470 DOI: 10.1038/s41467-019-12574-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 09/12/2019] [Indexed: 01/10/2023] Open
Abstract
Several recent studies have shown the presence of genes for the key enzyme associated with archaeal methane/alkane metabolism, methyl-coenzyme M reductase (Mcr), in metagenome-assembled genomes (MAGs) divergent to existing archaeal lineages. Here, we study the mcr-containing archaeal MAGs from several hot springs, which reveal further expansion in the diversity of archaeal organisms performing methane/alkane metabolism. Significantly, an MAG basal to organisms from the phylum Thaumarchaeota that contains mcr genes, but not those for ammonia oxidation or aerobic metabolism, is identified. Together, our phylogenetic analyses and ancestral state reconstructions suggest a mostly vertical evolution of mcrABG genes among methanogens and methanotrophs, along with frequent horizontal gene transfer of mcr genes between alkanotrophs. Analysis of all mcr-containing archaeal MAGs/genomes suggests a hydrothermal origin for these microorganisms based on optimal growth temperature predictions. These results also suggest methane/alkane oxidation or methanogenesis at high temperature likely existed in a common archaeal ancestor. Methane metabolism by some lineages of Archaea contributes to the cycling of carbon on Earth. Here, the authors show high diversity of methyl-coenzyme M reductase (Mcr), a key enzyme associated with archaeal methane/alkane metabolism, in hot spring Archaea, and investigate their ecological roles and evolution.
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Affiliation(s)
- Zheng-Shuang Hua
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, 510275, Guangzhou, PR China.,Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - Yu-Lin Wang
- Environmental Microbiome Engineering and Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, 999077, Hong Kong, SAR, PR China
| | - Paul N Evans
- The Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, 4072, QLD, Australia
| | - Yan-Ni Qu
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, 510275, Guangzhou, PR China
| | - Kian Mau Goh
- Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Skudai, Johor, 81310, Malaysia
| | - Yang-Zhi Rao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, 510275, Guangzhou, PR China
| | - Yan-Ling Qi
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, 510275, Guangzhou, PR China
| | - Yu-Xian Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, 510275, Guangzhou, PR China
| | - Min-Jun Huang
- Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - Jian-Yu Jiao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, 510275, Guangzhou, PR China
| | - Ya-Ting Chen
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, 510275, Guangzhou, PR China
| | - Yan-Ping Mao
- Environmental Microbiome Engineering and Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, 999077, Hong Kong, SAR, PR China.,College of Chemistry and Environmental Engineering, Shenzhen University, 518060, Shenzhen, PR China
| | - Wen-Sheng Shu
- School of Life Sciences, South China Normal University, 510631, Guangzhou, PR China
| | - Wael Hozzein
- Bioproducts Research Chair, Zoology Department, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.,Botany and Microbiology Department, Faculty of Science, Beni-Suef University, Beni-Suef, 65211, Egypt
| | - Brian P Hedlund
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, 89154, USA.,Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV, 89154, USA
| | - Gene W Tyson
- The Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, 4072, QLD, Australia. .,Advanced Water Management Centre, University of Queensland, St Lucia, 4072, QLD, Australia.
| | - Tong Zhang
- Environmental Microbiome Engineering and Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, 999077, Hong Kong, SAR, PR China.
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, 510275, Guangzhou, PR China. .,Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 830011, Urumqi, PR China.
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236
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High-Level Abundances of Methanobacteriales and Syntrophobacterales May Help To Prevent Corrosion of Metal Sheet Piles. Appl Environ Microbiol 2019; 85:AEM.01369-19. [PMID: 31420342 DOI: 10.1128/aem.01369-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/11/2019] [Indexed: 11/20/2022] Open
Abstract
Iron sheet piles are widely used in flood protection, dike construction, and river bank reinforcement. Their corrosion leads to gradual deterioration and often makes replacement necessary. Natural deposit layers on these sheet piles can prevent degradation and significantly increase their life span. However, little is known about the mechanisms of natural protective layer formation. Here, we studied the microbially diverse populations of corrosion-protective deposit layers on iron sheet piles at the Gouderak pumping station in Zuid-Holland, the Netherlands. Deposit layers, surrounding sediment and top sediment samples were analyzed for soil physicochemical parameters, microbially diverse populations, and metabolic potential. Methanogens appeared to be enriched 18-fold in the deposit layers. After sequencing, metagenome assembly and binning, we obtained four nearly complete draft genomes of microorganisms (Methanobacteriales, two Coriobacteriales, and Syntrophobacterales) that were highly enriched in the deposit layers, strongly indicating a potential role in corrosion protection. Coriobacteriales and Syntrophobacterales could be part of a microbial food web degrading organic matter to supply methanogenic substrates. Methane-producing Methanobacteriales could metabolize iron, which may initially lead to mild corrosion but potentially stimulates the formation of a carbonate-rich protective deposit layer in the long term. In addition, Methanobacteriales and Coriobacteriales have the potential to interact with metal surfaces via direct interspecies or extracellular electron transfer. In conclusion, our study provides valuable insights into microbial populations involved in iron corrosion protection and potentially enables the development of novel strategies for in situ screening of iron sheet piles in order to reduce risks and develop more sustainable replacement practices.IMPORTANCE Iron sheet piles are widely used to reinforce dikes and river banks. Damage due to iron corrosion poses a significant safety risk and has significant economic impact. Different groups of microorganisms are known to either stimulate or inhibit the corrosion process. Recently, natural corrosion-protective deposit layers were found on sheet piles. Analyses of the microbial composition indicated a potential role for methane-producing archaea. However, the full metabolic potential of the microbial communities within these protective layers has not been determined. The significance of this work lies in the reconstruction of the microbial food web of natural corrosion-protective layers isolated from noncorroding metal sheet piles. With this work, we provide insights into the microbiological mechanisms that potentially promote corrosion protection in freshwater ecosystems. Our findings could support the development of screening protocols to assess the integrity of iron sheet piles to decide whether replacement is required.
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237
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Onstott T, Ehlmann B, Sapers H, Coleman M, Ivarsson M, Marlow J, Neubeck A, Niles P. Paleo-Rock-Hosted Life on Earth and the Search on Mars: A Review and Strategy for Exploration. ASTROBIOLOGY 2019; 19:1230-1262. [PMID: 31237436 PMCID: PMC6786346 DOI: 10.1089/ast.2018.1960] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 04/25/2019] [Indexed: 05/19/2023]
Abstract
Here we review published studies on the abundance and diversity of terrestrial rock-hosted life, the environments it inhabits, the evolution of its metabolisms, and its fossil biomarkers to provide guidance in the search for life on Mars. Key findings are (1) much terrestrial deep subsurface metabolic activity relies on abiotic energy-yielding fluxes and in situ abiotic and biotic recycling of metabolic waste products rather than on buried organic products of photosynthesis; (2) subsurface microbial cell concentrations are highest at interfaces with pronounced chemical redox gradients or permeability variations and do not correlate with bulk host rock organic carbon; (3) metabolic pathways for chemolithoautotrophic microorganisms evolved earlier in Earth's history than those of surface-dwelling phototrophic microorganisms; (4) the emergence of the former occurred at a time when Mars was habitable, whereas the emergence of the latter occurred at a time when the martian surface was not continually habitable; (5) the terrestrial rock record has biomarkers of subsurface life at least back hundreds of millions of years and likely to 3.45 Ga with several examples of excellent preservation in rock types that are quite different from those preserving the photosphere-supported biosphere. These findings suggest that rock-hosted life would have been more likely to emerge and be preserved in a martian context. Consequently, we outline a Mars exploration strategy that targets subsurface life and scales spatially, focusing initially on identifying rocks with evidence for groundwater flow and low-temperature mineralization, then identifying redox and permeability interfaces preserved within rock outcrops, and finally focusing on finding minerals associated with redox reactions and associated traces of carbon and diagnostic chemical and isotopic biosignatures. Using this strategy on Earth yields ancient rock-hosted life, preserved in the fossil record and confirmable via a suite of morphologic, organic, mineralogical, and isotopic fingerprints at micrometer scale. We expect an emphasis on rock-hosted life and this scale-dependent strategy to be crucial in the search for life on Mars.
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Affiliation(s)
- T.C. Onstott
- Department of Geosciences, Princeton University, Princeton, New Jersey, USA
- Address correspondence to: T.C. Onstott, Department of Geosciences, Princeton University,, Princeton, NJ 008544
| | - B.L. Ehlmann
- Division of Geological & Planetary Sciences, California Institute of Technology, Pasadena, California, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- B.L. Ehlmann, Division of Geological & Planetary Sciences, California Institute of Technology, Pasadena, CA 91125
| | - H. Sapers
- Division of Geological & Planetary Sciences, California Institute of Technology, Pasadena, California, USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- Department of Earth Sciences, University of Southern California, Los Angeles, California, USA
| | - M. Coleman
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- NASA Astrobiology Institute, Pasadena, California, USA
| | - M. Ivarsson
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - J.J. Marlow
- Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - A. Neubeck
- Department of Earth Sciences, Uppsala University, Uppsala, Sweden
| | - P. Niles
- Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, Texas, USA
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238
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A genomic view of the reef-building coral Porites lutea and its microbial symbionts. Nat Microbiol 2019; 4:2090-2100. [DOI: 10.1038/s41564-019-0532-4] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 07/05/2019] [Indexed: 11/09/2022]
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239
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Finke N, Simister RL, O'Neil AH, Nomosatryo S, Henny C, MacLean LC, Canfield DE, Konhauser K, Lalonde SV, Fowle DA, Crowe SA. Mesophilic microorganisms build terrestrial mats analogous to Precambrian microbial jungles. Nat Commun 2019; 10:4323. [PMID: 31541087 PMCID: PMC6754388 DOI: 10.1038/s41467-019-11541-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 07/03/2019] [Indexed: 12/02/2022] Open
Abstract
Development of Archean paleosols and patterns of Precambrian rock weathering suggest colonization of continents by subaerial microbial mats long before evolution of land plants in the Phanerozoic Eon. Modern analogues for such mats, however, have not been reported, and possible biogeochemical roles of these mats in the past remain largely conceptual. We show that photosynthetic, subaerial microbial mats from Indonesia grow on mafic bedrocks at ambient temperatures and form distinct layers with features similar to Precambrian mats and paleosols. Such subaerial mats could have supported a substantial aerobic biosphere, including nitrification and methanotrophy, and promoted methane emissions and oxidative weathering under ostensibly anoxic Precambrian atmospheres. High C-turnover rates and cell abundances would have made these mats prime locations for early microbial diversification. Growth of landmass in the late Archean to early Proterozoic Eons could have reorganized biogeochemical cycles between land and sea impacting atmospheric chemistry and climate.
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Affiliation(s)
- N Finke
- Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
- Nordic center for earth evolution (NordCEE), University of Southern Denmark, Odense, Denmark
| | - R L Simister
- Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | | | - S Nomosatryo
- Research center for Limnology, Indonesian Institute of Sciences (LIPI), Jawa Barat, Indonesia
- GFZ German Research Centre for Geosciences, Potsdam, Germany
| | - C Henny
- Research center for Limnology, Indonesian Institute of Sciences (LIPI), Jawa Barat, Indonesia
| | | | - D E Canfield
- Nordic center for earth evolution (NordCEE), University of Southern Denmark, Odense, Denmark
| | - K Konhauser
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Canada
| | - S V Lalonde
- European Institute for Marine Studies, Technopôle Brest-Iroise, Plouzané, France
| | - D A Fowle
- Department of Geology, University of Kansas, Lawrence, KS, USA
| | - S A Crowe
- Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada.
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Energy Conservation and Hydrogenase Function in Methanogenic Archaea, in Particular the Genus Methanosarcina. Microbiol Mol Biol Rev 2019; 83:83/4/e00020-19. [PMID: 31533962 DOI: 10.1128/mmbr.00020-19] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The biological production of methane is vital to the global carbon cycle and accounts for ca. 74% of total methane emissions. The organisms that facilitate this process, methanogenic archaea, belong to a large and phylogenetically diverse group that thrives in a wide range of anaerobic environments. Two main subgroups exist within methanogenic archaea: those with and those without cytochromes. Although a variety of metabolisms exist within this group, the reduction of growth substrates to methane using electrons from molecular hydrogen is, in a phylogenetic sense, the most widespread methanogenic pathway. Methanogens without cytochromes typically generate methane by the reduction of CO2 with electrons derived from H2, formate, or secondary alcohols, generating a transmembrane ion gradient for ATP production via an Na+-translocating methyltransferase (Mtr). These organisms also conserve energy with a novel flavin-based electron bifurcation mechanism, wherein the endergonic reduction of ferredoxin is facilitated by the exergonic reduction of a disulfide terminal electron acceptor coupled to either H2 or formate oxidation. Methanogens that utilize cytochromes have a broader substrate range, and can convert acetate and methylated compounds to methane, in addition to the ability to reduce CO2 Cytochrome-containing methanogens are able to supplement the ion motive force generated by Mtr with an H+-translocating electron transport system. In both groups, enzymes known as hydrogenases, which reversibly interconvert protons and electrons to molecular hydrogen, play a central role in the methanogenic process. This review discusses recent insight into methanogen metabolism and energy conservation mechanisms with a particular focus on the genus Methanosarcina.
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241
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Changes in the Substrate Source Reveal Novel Interactions in the Sediment-Derived Methanogenic Microbial Community. Int J Mol Sci 2019; 20:ijms20184415. [PMID: 31500341 PMCID: PMC6770359 DOI: 10.3390/ijms20184415] [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] [Received: 07/15/2019] [Revised: 09/05/2019] [Accepted: 09/06/2019] [Indexed: 12/23/2022] Open
Abstract
Methanogenesis occurs in many natural environments and is used in biotechnology for biogas production. The efficiency of methane production depends on the microbiome structure that determines interspecies electron transfer. In this research, the microbial community retrieved from mining subsidence reservoir sediment was used to establish enrichment cultures on media containing different carbon sources (tryptone, yeast extract, acetate, CO2/H2). The microbiome composition and methane production rate of the cultures were screened as a function of the substrate and transition stage. The relationships between the microorganisms involved in methane formation were the major focus of this study. Methanogenic consortia were identified by next generation sequencing (NGS) and functional genes connected with organic matter transformation were predicted using the PICRUSt approach and annotated in the KEGG. The methane production rate (exceeding 12.8 mg CH4 L−1 d−1) was highest in the culture grown with tryptone, yeast extract, and CO2/H2. The analysis of communities that developed on various carbon sources casts new light on the ecophysiology of the recently described bacterial phylum Caldiserica and methanogenic Archaea representing the genera Methanomassiliicoccus and Methanothrix. Furthermore, it is hypothesized that representatives of Caldiserica may support hydrogenotrophic methanogenesis.
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Laso-Pérez R, Hahn C, van Vliet DM, Tegetmeyer HE, Schubotz F, Smit NT, Pape T, Sahling H, Bohrmann G, Boetius A, Knittel K, Wegener G. Anaerobic Degradation of Non-Methane Alkanes by " Candidatus Methanoliparia" in Hydrocarbon Seeps of the Gulf of Mexico. mBio 2019; 10:e01814-19. [PMID: 31431553 PMCID: PMC6703427 DOI: 10.1128/mbio.01814-19] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 07/24/2019] [Indexed: 11/20/2022] Open
Abstract
Crude oil and gases in the seabed provide an important energy source for subsurface microorganisms. We investigated the role of archaea in the anaerobic degradation of non-methane alkanes in deep-sea oil seeps from the Gulf of Mexico. We identified microscopically the ethane and short-chain alkane oxidizers "Candidatus Argoarchaeum" and "Candidatus Syntrophoarchaeum" forming consortia with bacteria. Moreover, we found that the sediments contain large numbers of cells from the archaeal clade "Candidatus Methanoliparia," which was previously proposed to perform methanogenic alkane degradation. "Ca. Methanoliparia" occurred abundantly as single cells attached to oil droplets in sediments without apparent bacterial or archaeal partners. Metagenome-assembled genomes of "Ca. Methanoliparia" encode a complete methanogenesis pathway including a canonical methyl-coenzyme M reductase (MCR) but also a highly divergent MCR related to those of alkane-degrading archaea and pathways for the oxidation of long-chain alkyl units. Its metabolic genomic potential and its global detection in hydrocarbon reservoirs suggest that "Ca. Methanoliparia" is an important methanogenic alkane degrader in subsurface environments, producing methane by alkane disproportionation as a single organism.IMPORTANCE Oil-rich sediments from the Gulf of Mexico were found to contain diverse alkane-degrading groups of archaea. The symbiotic, consortium-forming "Candidatus Argoarchaeum" and "Candidatus Syntrophoarchaeum" are likely responsible for the degradation of ethane and short-chain alkanes, with the help of sulfate-reducing bacteria. "Ca. Methanoliparia" occurs as single cells associated with oil droplets. These archaea encode two phylogenetically different methyl-coenzyme M reductases that may allow this organism to thrive as a methanogen on a substrate of long-chain alkanes. Based on a library survey, we show that "Ca. Methanoliparia" is frequently detected in oil reservoirs and may be a key agent in the transformation of long-chain alkanes to methane. Our findings provide evidence for the important and diverse roles of archaea in alkane-rich marine habitats and support the notion of a significant functional versatility of the methyl coenzyme M reductase.
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Affiliation(s)
- Rafael Laso-Pérez
- Max-Planck Institute for Marine Microbiology, Bremen, Germany
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
- MARUM, Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Cedric Hahn
- Max-Planck Institute for Marine Microbiology, Bremen, Germany
| | - Daan M van Vliet
- Laboratory of Microbiology, Wageningen University and Research, Wageningen, The Netherlands
| | - Halina E Tegetmeyer
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
- Center for Biotechnology, Bielefeld University, Bielefeld, Germany
| | - Florence Schubotz
- MARUM, Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Nadine T Smit
- MARUM, Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Thomas Pape
- MARUM, Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Heiko Sahling
- MARUM, Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Gerhard Bohrmann
- MARUM, Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Antje Boetius
- Max-Planck Institute for Marine Microbiology, Bremen, Germany
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
- MARUM, Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Katrin Knittel
- Max-Planck Institute for Marine Microbiology, Bremen, Germany
| | - Gunter Wegener
- Max-Planck Institute for Marine Microbiology, Bremen, Germany
- Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
- MARUM, Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
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243
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Boyd JA, Woodcroft BJ, Tyson GW. GraftM: a tool for scalable, phylogenetically informed classification of genes within metagenomes. Nucleic Acids Res 2019; 46:e59. [PMID: 29562347 PMCID: PMC6007438 DOI: 10.1093/nar/gky174] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/06/2018] [Indexed: 12/01/2022] Open
Abstract
Large-scale metagenomic datasets enable the recovery of hundreds of population genomes from environmental samples. However, these genomes do not typically represent the full diversity of complex microbial communities. Gene-centric approaches can be used to gain a comprehensive view of diversity by examining each read independently, but traditional pairwise comparison approaches typically over-classify taxonomy and scale poorly with increasing metagenome and database sizes. Here we introduce GraftM, a tool that uses gene specific packages to rapidly identify gene families in metagenomic data using hidden Markov models (HMMs) or DIAMOND databases, and classifies these sequences using placement into pre-constructed gene trees. The speed and accuracy of GraftM was benchmarked with in silico and in vitro mock communities using taxonomic markers, and was found to have higher accuracy at the family level with a processing time 2.0–3.7× faster than currently available software. Exploration of a wetland metagenome using 16S rRNA- and methyl-coenzyme M reductase (McrA)-specific gpkgs revealed taxonomic and functional shifts across a depth gradient. Analysis of the NCBI nr database using the McrA gpkg allowed the detection of novel sequences belonging to phylum-level lineages. A growing collection of gpkgs is available online (https://github.com/geronimp/graftM_gpkgs), where curated packages can be uploaded and exchanged.
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Affiliation(s)
- Joel A Boyd
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Queensland, Australia
| | - Ben J Woodcroft
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Queensland, Australia
| | - Gene W Tyson
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Queensland, Australia
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244
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Houghton KM, Carere CR, Stott MB, McDonald IR. Thermophilic methanotrophs: in hot pursuit. FEMS Microbiol Ecol 2019; 95:5543213. [DOI: 10.1093/femsec/fiz125] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 07/31/2019] [Indexed: 11/13/2022] Open
Abstract
ABSTRACTMethane is a potent greenhouse gas responsible for 20–30% of global climate change effects. The global methane budget is ∼500–600 Tg y−1, with the majority of methane produced via microbial processes, including anthropogenic-mediated sources such as ruminant animals, rice fields, sewage treatment facilities and landfills. It is estimated that microbially mediated methane oxidation (methanotrophy) consumes >50% of global methane flux each year. Methanotrophy research has primarily focused on mesophilic methanotrophic representatives and cooler environments such as freshwater, wetlands or marine habitats from which they are sourced. Nevertheless, geothermal emissions of geological methane, produced from magma and lithosphere degassing micro-seepages, mud volcanoes and other geological sources, contribute an estimated 33–75 Tg y−1 to the global methane budget. The aim of this review is to summarise current literature pertaining to the activity of thermophilic and thermotolerant methanotrophs, both proteobacterial (Methylocaldum, Methylococcus, Methylothermus) and verrucomicrobial (Methylacidiphilum). We assert, on the basis of recently reported molecular and geochemical data, that geothermal ecosystems host hitherto unidentified species capable of methane oxidation at higher temperatures.
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Affiliation(s)
- Karen M Houghton
- GNS Science, Wairakei Research Centre, 114 Karetoto Rd, Taupō 3384, New Zealand
- School of Science, University of Waikato, Knighton Rd, Hamilton 3240, New Zealand
| | - Carlo R Carere
- GNS Science, Wairakei Research Centre, 114 Karetoto Rd, Taupō 3384, New Zealand
- Department of Chemical and Process Engineering, University of Canterbury, 20 Kirkwood Ave, Upper Riccarton, Christchurch 8041, New Zealand
| | - Matthew B Stott
- GNS Science, Wairakei Research Centre, 114 Karetoto Rd, Taupō 3384, New Zealand
- School of Biological Sciences, University of Canterbury, 20 Kirkwood Ave, Upper Riccarton, Christchurch 8041, New Zealand
| | - Ian R McDonald
- School of Science, University of Waikato, Knighton Rd, Hamilton 3240, New Zealand
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245
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Microbial communities involved in the methane cycle in the near-bottom water layer and sediments of the meromictic subarctic Lake Svetloe. Antonie van Leeuwenhoek 2019; 112:1801-1814. [PMID: 31372944 DOI: 10.1007/s10482-019-01308-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 07/24/2019] [Indexed: 02/07/2023]
Abstract
Although arctic and subarctic lakes are important sources of methane, the emission of which will increase due to the melting of permafrost, the processes related to the methane cycle in such environments are far from being comprehensively understood. Here we studied the microbial communities in the near-bottom water layer and sediments of the meromictic subarctic Lake Svetloe using high-throughput sequencing of the 16S rRNA and methyl coenzyme M reductase subunit A genes. Hydrogenotrophic methanogens of the order Methanomicrobiales were abundant, both in the water column and in sediments, while the share of acetoclastic Methanosaetaceae decreased with the depth of sediments. Members of the Methanomassiliicoccales order were absent in the water but abundant in the deep sediments. Archaea known to perform anaerobic oxidation of methane were not found. The bacterial component of the microbial community in the bottom water layer included oxygenic (Cyanobacteria) and anoxygenic (Chlorobi) phototrophs, aerobic Type I methanotrophs, methylotrophs, syntrophs, and various organotrophs. In deeper sediments the diversity of the microbial community decreased, and it became dominated by methanogenic archaea and the members of the Bathyarchaeota, Chloroflexi and Deltaproteobacteria. This study shows that the sediments of a subarctic meromictic lake contain a taxonomically and metabolically diverse community potentially capable of complete mineralization of organic matter.
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246
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Kujala K, Mikkonen A, Saravesi K, Ronkanen AK, Tiirola M. Microbial diversity along a gradient in peatlands treating mining-affected waters. FEMS Microbiol Ecol 2019; 94:5066165. [PMID: 30137344 DOI: 10.1093/femsec/fiy145] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 08/02/2018] [Indexed: 01/27/2023] Open
Abstract
Peatlands are used for the purification of mining-affected waters in Northern Finland. In Northern climate, microorganisms in treatment peatlands (TPs) are affected by long and cold winters, but studies about those microorganisms are scarce. Thus, the bacterial, archaeal and fungal communities along gradients of mine water influence in two TPs were investigated. The TPs receive waters rich in contaminants, including arsenic (As), sulfate (SO42-) and nitrate (NO3-). Microbial diversity was high in both TPs, and microbial community composition differed between the studied TPs. Bacterial communities were dominated by Proteobacteria, Actinobacteria, Chloroflexi and Acidobacteria, archaeal communities were dominated by Methanomicrobia and the Candidate phylum Bathyarchaeota, and fungal communities were dominated by Ascomycota (Leotiomycetes, Dothideomycetes, Sordariomycetes). The functional potential of the bacterial and archaeal communities in TPs was predicted using PICRUSt. Sampling points affected by high concentrations of As showed higher relative abundance of predicted functions related to As resistance. Functions potentially involved in nitrogen and SO42- turnover in TPs were predicted for both TPs. The results obtained in this study indicate that (i) diverse microbial communities exist in Northern TPs, (ii) the functional potential of the peatland microorganisms is beneficial for contaminant removal in TPs and (iii) microorganisms in TPs are likely well-adapted to high contaminant concentrations as well as to the Northern climate.
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Affiliation(s)
- Katharina Kujala
- Water Resources and Environmental Engineering Research Unit, University of Oulu, PO Box 4300, FI-90014 Oulu, Finland
| | - Anu Mikkonen
- Department of Biological and Environmental Science, Nanoscience Center, University of Jyväskylä, PO Box 35, FI-40014 University of Jyväskylä, Finland
| | - Karita Saravesi
- Department of Ecology and Genetics, University of Oulu, PO Box 3000, FI-90014 Oulu, Finland
| | - Anna-Kaisa Ronkanen
- Water Resources and Environmental Engineering Research Unit, University of Oulu, PO Box 4300, FI-90014 Oulu, Finland
| | - Marja Tiirola
- Department of Biological and Environmental Science, Nanoscience Center, University of Jyväskylä, PO Box 35, FI-40014 University of Jyväskylä, Finland
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247
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Bomberg M, Claesson Liljedahl L, Lamminmäki T, Kontula A. Highly Diverse Aquatic Microbial Communities Separated by Permafrost in Greenland Show Distinct Features According to Environmental Niches. Front Microbiol 2019; 10:1583. [PMID: 31354674 PMCID: PMC6637822 DOI: 10.3389/fmicb.2019.01583] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 06/25/2019] [Indexed: 11/13/2022] Open
Abstract
The Greenland Analog Project (GAP) study area in the vicinity of Kangarlussuaq, Western Greenland, was sampled for surface water and deep groundwater in order to determine the composition and estimate the metabolic features of the microbial communities in water bodies separated by permafrost. The sampling sites comprised a freshwater pond, talik lake, deep anoxic groundwater, glacier ice and supraglacial river, meltwater river and melting permafrost active layer. The microbial communities were characterized by amplicon sequencing of the bacterial and archaeal 16S rRNA genes and fungal ITS1 spacer. In addition, bacterial, archaeal and fungal numbers were determined by qPCR and plate counts, and the utilization pattern of carbon and nitrogen substrates was determined with Biolog AN plates and metabolic functions were predicted with FAPROTAX. Different sample types were clearly distinguishable from each other based on community composition, microbial numbers, and substrate utilization patterns, forming four groups, (1) pond/lake, (2) deep groundwater, (3) glacial ice, and (4) meltwater. Bacteria were the most abundant microbial domain, ranging from 0.2–1.4 × 107 16S rRNA gene copies mL-1 in pond/lake and meltwater, 0.1-7.8 × 106 copies mL-1 in groundwater and less than 104 copies mL-1 in ice. The number of archaeal 16S and fungal 5.8S rRNA genes was generally less than 6.0 × 103 and 1.5 × 103, respectively. N2-fixing and methane-oxidizing Actinomycetes, Bacteroidetes and Verrucomicrobia were the dominant microorganisms in the pond/lake samples, whereas iron reducing Desulfosporosinus sp. dominated the deep anaerobic groundwater. The glacial ice was inhabited by Cyanobacteria, which were mostly Chloroplast-like. The meltwater contained methano- and methylotrophic Proteobacteria, but had also high relative abundances of the nano-sized Parcubacteria. The archaea composed approximately 1% of the 16S rRNA gene pool in the pond/lake samples with nano-sized Woesearchaeota as the dominating taxon, while in the other sample types archaea were almost negligent. Fungi were also most common in the pond/lake communities, were zoospore-forming Chytridiomycetes dominated. Our results show highly diverse microbial communities inhabiting the different cold Greenlandic aqueous environments and show clear segregation of the microbial communities according to habitat, with distinctive dominating metabolic features specifically inhabiting defined environmental niches and a high relative abundance of putatively parasitic or symbiotic nano-sized taxa.
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Affiliation(s)
- Malin Bomberg
- VTT Technical Research Centre of Finland Ltd., Espoo, Finland
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248
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Yi XY, Yang YP, Yuan HY, Chen Z, Duan GL, Zhu YG. Coupling metabolisms of arsenic and iron with humic substances through microorganisms in paddy soil. JOURNAL OF HAZARDOUS MATERIALS 2019; 373:591-599. [PMID: 30952004 DOI: 10.1016/j.jhazmat.2019.03.113] [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: 12/27/2018] [Revised: 03/20/2019] [Accepted: 03/26/2019] [Indexed: 05/12/2023]
Abstract
Humic acid (HA) and fulvic acid (FA) are dominating humic substances (HS) in soil. In this study, the effects of HA and FA addition (0.2%-1.5%) on arsenic (As) mobility and microbial community composition in paddy soil were investigated. FA significantly increased the concentrations of As (12-fold), iron (Fe; 20-fold), manganese (Mn; 3-fold) and acetic acid (3-fold) in soil porewater, and also caused significant enrichment of Desulfitobacterium (41-fold). Furthermore, the FA addition significantly increased the relative abundance of Bathyarchaeota (4-fold), a microorganism that is suggested to be important for FA degradation. In contrast, HA slightly increased As (1.2-fold) in porewater, had little effect on Fe, Mn and acetic acid, and 1.5% HA addition significantly decreased As in porewater at day 14 (45%). Both HA and FA addition promoted As methylation. HA increased dimethylarsenate concentration and FA increased monomethylarsenate concentration in porewater. These results highlight the contrasting effects of different (HA vs. FA) organic substances on As fate in paddy soil and advance our understanding of the associations among As, Fe and organic substances through microorganisms in paddy soil.
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Affiliation(s)
- Xing-Yun Yi
- State Key Lab 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
| | - Yu-Ping Yang
- State Key Lab 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
| | - Hai-Yan Yuan
- State Key Lab 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
| | - Zheng Chen
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, 215123, People's Republic of China
| | - Gui-Lan Duan
- State Key Lab 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.
| | - Yong-Guan Zhu
- State Key Lab 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; Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, People's Republic of China
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249
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Dong L, Cao G, Wu J, Yang S, Ren N. Reflux of acidizing fluid for enhancing biomethane production from cattle manure in plug flow reactor. BIORESOURCE TECHNOLOGY 2019; 284:248-255. [PMID: 30947139 DOI: 10.1016/j.biortech.2019.03.092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/15/2019] [Accepted: 03/17/2019] [Indexed: 06/09/2023]
Abstract
The performance and microbial community succession of a 36 L working volume plug flow reactor was evaluated for treated cattle manure at an organic loading rate of 2.67 g-TS/L/day, a temperature of 38 °C ± 1 °C, and a hydraulic retention time of 18 days. A reflux of acidizing fluid effectively enhanced anaerobic digestion performance and promoted optimization of microbial community structure. The average biogas volume production rate was 1.08 L biogas/L reactor, which was 116.5% higher than the control without reflux of acidizing fluid. The specific qmethane production yield and methane content reached 0.204 L/g VS and 70%. Moreover, methane yield achieved 0.34 m3/kg removal COD with a COD removal of about 70.56%. The bacteria genera Christensenellaceae, Bacteroidales, vadinBC27, Ruminococcaceae and Treponema_2 were further enriched. Methanosarcina became the dominant methanogen in the whole PFR operation process. This study offers new opportunities for producing renewable energy from enhanced cattle manure biodegradability.
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Affiliation(s)
- Lili Dong
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Guangli Cao
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Jiwen Wu
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shanshan Yang
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
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250
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Greening C, Geier R, Wang C, Woods LC, Morales SE, McDonald MJ, Rushton-Green R, Morgan XC, Koike S, Leahy SC, Kelly WJ, Cann I, Attwood GT, Cook GM, Mackie RI. Diverse hydrogen production and consumption pathways influence methane production in ruminants. ISME JOURNAL 2019; 13:2617-2632. [PMID: 31243332 PMCID: PMC6776011 DOI: 10.1038/s41396-019-0464-2] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 06/03/2019] [Accepted: 06/07/2019] [Indexed: 01/17/2023]
Abstract
Farmed ruminants are the largest source of anthropogenic methane emissions globally. The methanogenic archaea responsible for these emissions use molecular hydrogen (H2), produced during bacterial and eukaryotic carbohydrate fermentation, as their primary energy source. In this work, we used comparative genomic, metatranscriptomic and co-culture-based approaches to gain a system-wide understanding of the organisms and pathways responsible for ruminal H2 metabolism. Two-thirds of sequenced rumen bacterial and archaeal genomes encode enzymes that catalyse H2 production or consumption, including 26 distinct hydrogenase subgroups. Metatranscriptomic analysis confirmed that these hydrogenases are differentially expressed in sheep rumen. Electron-bifurcating [FeFe]-hydrogenases from carbohydrate-fermenting Clostridia (e.g., Ruminococcus) accounted for half of all hydrogenase transcripts. Various H2 uptake pathways were also expressed, including methanogenesis (Methanobrevibacter), fumarate and nitrite reduction (Selenomonas), and acetogenesis (Blautia). Whereas methanogenesis-related transcripts predominated in high methane yield sheep, alternative uptake pathways were significantly upregulated in low methane yield sheep. Complementing these findings, we observed significant differential expression and activity of the hydrogenases of the hydrogenogenic cellulose fermenter Ruminococcus albus and the hydrogenotrophic fumarate reducer Wolinella succinogenes in co-culture compared with pure culture. We conclude that H2 metabolism is a more complex and widespread trait among rumen microorganisms than previously recognised. There is evidence that alternative hydrogenotrophs, including acetogenic and respiratory bacteria, can prosper in the rumen and effectively compete with methanogens for H2. These findings may help to inform ongoing strategies to mitigate methane emissions by increasing flux through alternative H2 uptake pathways, including through animal selection, dietary supplementation and methanogenesis inhibitors.
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Affiliation(s)
- Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia.
| | - Renae Geier
- Department of Animal Sciences and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Cecilia Wang
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9016, New Zealand
| | - Laura C Woods
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Sergio E Morales
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9016, New Zealand
| | - Michael J McDonald
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Rowena Rushton-Green
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9016, New Zealand
| | - Xochitl C Morgan
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9016, New Zealand
| | - Satoshi Koike
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Sinead C Leahy
- Grasslands Research Centre, AgResearch Ltd., Palmerston North, 4410, New Zealand
| | | | - Isaac Cann
- Department of Animal Sciences and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Graeme T Attwood
- Grasslands Research Centre, AgResearch Ltd., Palmerston North, 4410, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9016, New Zealand
| | - Roderick I Mackie
- Department of Animal Sciences and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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