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Xu Y, Teng Y, Wang X, Wang H, Li Y, Ren W, Zhao L, Wei M, Luo Y. Biohydrogen utilization in legume-rhizobium symbiosis reveals a novel mechanism of accelerated tetrachlorobiphenyl transformation. BIORESOURCE TECHNOLOGY 2024; 404:130918. [PMID: 38823562 DOI: 10.1016/j.biortech.2024.130918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 05/23/2024] [Accepted: 05/30/2024] [Indexed: 06/03/2024]
Abstract
Symbiosis between Glycine max and Bradyrhizobium diazoefficiens were used as a model system to investigate whether biohydrogen utilization promotes the transformation of the tetrachlorobiphenyl PCB77. Both a H2 uptake-positive (Hup+) strain (wild type) and a Hup- strain (a hupL deletion mutant) were inoculated into soybean nodules. Compared with Hup- nodules, Hup+ nodules increased dechlorination significantly by 61.1 % and reduced the accumulation of PCB77 in nodules by 37.7 % (p < 0.05). After exposure to nickel, an enhancer of uptake hydrogenase, dechlorination increased significantly by 2.2-fold, and the accumulation of PCB77 in nodules decreased by 54.4 % (p < 0.05). Furthermore, the tetrachlorobiphenyl transformation in the soybean root nodules was mainly testified to be mediated by nitrate reductase (encoded by the gene NR) for tetrachlorobiphenyl dechlorination and biphenyl-2,3-diol 1,2-dioxygenase (bphC) for biphenyl degradation. This study demonstrates for the first time that biohydrogen utilization has a beneficial effect on tetrachlorobiphenyl biotransformation in a legume-rhizobium symbiosis.
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Affiliation(s)
- Yongfeng Xu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying Teng
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Xiaomi Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongzhe Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanning Li
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjie Ren
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ling Zhao
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Wei
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Yongming Luo
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Greening C, Cabotaje PR, Valentin Alvarado LE, Leung PM, Land H, Rodrigues-Oliveira T, Ponce-Toledo RI, Senger M, Klamke MA, Milton M, Lappan R, Mullen S, West-Roberts J, Mao J, Song J, Schoelmerich M, Stairs CW, Schleper C, Grinter R, Spang A, Banfield JF, Berggren G. Minimal and hybrid hydrogenases are active from archaea. Cell 2024:S0092-8674(24)00573-7. [PMID: 38866018 DOI: 10.1016/j.cell.2024.05.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 04/12/2024] [Accepted: 05/16/2024] [Indexed: 06/14/2024]
Abstract
Microbial hydrogen (H2) cycling underpins the diversity and functionality of diverse anoxic ecosystems. Among the three evolutionarily distinct hydrogenase superfamilies responsible, [FeFe] hydrogenases were thought to be restricted to bacteria and eukaryotes. Here, we show that anaerobic archaea encode diverse, active, and ancient lineages of [FeFe] hydrogenases through combining analysis of existing and new genomes with extensive biochemical experiments. [FeFe] hydrogenases are encoded by genomes of nine archaeal phyla and expressed by H2-producing Asgard archaeon cultures. We report an ultraminimal hydrogenase in DPANN archaea that binds the catalytic H-cluster and produces H2. Moreover, we identify and characterize remarkable hybrid complexes formed through the fusion of [FeFe] and [NiFe] hydrogenases in ten other archaeal orders. Phylogenetic analysis and structural modeling suggest a deep evolutionary history of hybrid hydrogenases. These findings reveal new metabolic adaptations of archaea, streamlined H2 catalysts for biotechnological development, and a surprisingly intertwined evolutionary history between the two major H2-metabolizing enzymes.
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Affiliation(s)
- Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia; SAEF: Securing Antarctica's Environmental Future, Monash University, Clayton, VIC, Australia.
| | - Princess R Cabotaje
- Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Luis E Valentin Alvarado
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94709, USA
| | - Pok Man Leung
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia; SAEF: Securing Antarctica's Environmental Future, Monash University, Clayton, VIC, Australia
| | - Henrik Land
- Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Thiago Rodrigues-Oliveira
- Department of Functional and Evolutionary Ecology, Archaea Biology and Ecogenomics Unit, University of Vienna, Vienna, Austria
| | - Rafael I Ponce-Toledo
- Department of Functional and Evolutionary Ecology, Archaea Biology and Ecogenomics Unit, University of Vienna, Vienna, Austria
| | - Moritz Senger
- Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Max A Klamke
- Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Michael Milton
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Rachael Lappan
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia; SAEF: Securing Antarctica's Environmental Future, Monash University, Clayton, VIC, Australia
| | - Susan Mullen
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94709, USA
| | - Jacob West-Roberts
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94709, USA
| | - Jie Mao
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia; Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Jiangning Song
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Marie Schoelmerich
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94709, USA
| | | | - Christa Schleper
- Department of Functional and Evolutionary Ecology, Archaea Biology and Ecogenomics Unit, University of Vienna, Vienna, Austria
| | - Rhys Grinter
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.
| | - Anja Spang
- Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Den Hoorn, the Netherlands; Department of Evolutionary and Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands.
| | - Jillian F Banfield
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia; Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94709, USA.
| | - Gustav Berggren
- Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden.
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3
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Ma Y, Qu Y, Yao X, Xia C, Lv M, Lin X, Zhang L, Zhang M, Hu B. Unveiling the unique role of iron in the metabolism of methanogens: A review. ENVIRONMENTAL RESEARCH 2024; 250:118495. [PMID: 38367837 DOI: 10.1016/j.envres.2024.118495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/06/2024] [Accepted: 02/13/2024] [Indexed: 02/19/2024]
Abstract
Methanogens are the main participants in the carbon cycle, catalyzing five methanogenic pathways. Methanogens utilize different iron-containing functional enzymes in different methanogenic processes. Iron is a vital element in methanogens, which can serve as a carrier or reactant in electron transfer. Therefore, iron plays an important role in the growth and metabolism of methanogens. In this paper, we cast light on the types and functions of iron-containing functional enzymes involved in different methanogenic pathways, and the roles iron play in energy/substance metabolism of methanogenesis. Furthermore, this review provides certain guiding significance for lowering CH4 emissions, boosting the carbon sink capacity of ecosystems and promoting green and low-carbon development in the future.
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Affiliation(s)
- Yuxin Ma
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China; Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ying Qu
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiangwu Yao
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, Zhejiang, China; Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chujun Xia
- Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Mengjie Lv
- Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiao Lin
- Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lili Zhang
- Beijing Enterprises Water Group Limited, Beijing, China
| | - Meng Zhang
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, Zhejiang, China; Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Baolan Hu
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, Zhejiang, China; Department of Environmental Engineering, Zhejiang University, Hangzhou, Zhejiang, China.
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Demin KA, Prazdnova EV, Minkina TM, Gorovtsov AV. Sulfate-reducing bacteria unearthed: ecological functions of the diverse prokaryotic group in terrestrial environments. Appl Environ Microbiol 2024; 90:e0139023. [PMID: 38551370 PMCID: PMC11022543 DOI: 10.1128/aem.01390-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2024] Open
Abstract
Sulfate-reducing prokaryotes (SRPs) are essential microorganisms that play crucial roles in various ecological processes. Even though SRPs have been studied for over a century, there are still gaps in our understanding of their biology. In the past two decades, a significant amount of data on SRP ecology has been accumulated. This review aims to consolidate that information, focusing on SRPs in soils, their relation to the rare biosphere, uncultured sulfate reducers, and their interactions with other organisms in terrestrial ecosystems. SRPs in soils form part of the rare biosphere and contribute to various processes as a low-density population. The data reveal a diverse range of sulfate-reducing taxa intricately involved in terrestrial carbon and sulfur cycles. While some taxa like Desulfitobacterium and Desulfosporosinus are well studied, others are more enigmatic. For example, members of the Acidobacteriota phylum appear to hold significant importance for the terrestrial sulfur cycle. Many aspects of SRP ecology remain mysterious, including sulfate reduction in different bacterial phyla, interactions with bacteria and fungi in soils, and the existence of soil sulfate-reducing archaea. Utilizing metagenomic, metatranscriptomic, and culture-dependent approaches will help uncover the diversity, functional potential, and adaptations of SRPs in the global environment.
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Woern C, Grossmann L. Microbial gas fermentation technology for sustainable food protein production. Biotechnol Adv 2023; 69:108240. [PMID: 37647973 DOI: 10.1016/j.biotechadv.2023.108240] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/16/2023] [Accepted: 08/21/2023] [Indexed: 09/01/2023]
Abstract
The development of novel, sustainable, and robust food production technologies represents one of the major pillars to address the most significant challenges humanity is going to face on earth in the upcoming decades - climate change, population growth, and resource depletion. The implementation of microfoods, i.e., foods formulated with ingredients from microbial cultivation, into the food supply chain has a huge potential to contribute towards energy-efficient and nutritious food manufacturing and represents a means to sustainably feed a growing world population. This review recapitulates and assesses the current state in the establishment and usage of gas fermenting bacteria as an innovative feedstock for protein production. In particular, we focus on the most promising representatives of this taxon: the hydrogen-oxidizing bacteria (hydrogenotrophs) and the methane-oxidizing bacteria (methanotrophs). These unicellular microorganisms can aerobically metabolize gaseous hydrogen and methane, respectively, to provide the required energy for building up cell material. A protein yield over 70% in the dry matter cell mass can be reached with no need for arable land and organic substrates making it a promising alternative to plant- and animal-based protein sources. We illuminate the holistic approach to incorporate protein extracts obtained from the cultivation of gas fermenting bacteria into microfoods. Herein, the fundamental properties of the bacteria, cultivation methods, downstream processing, and potential food applications are discussed. Moreover, this review covers existing and future challenges as well as sustainability aspects associated with the production of microbial protein through gas fermentation.
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Affiliation(s)
- Carlos Woern
- Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA
| | - Lutz Grossmann
- Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA.
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Cheng P, Wang Y, Cai C, Li L, Zeng Y, Cheng X, Shen W. Molecular hydrogen positively regulates nitrate uptake and seed size by targeting nitrate reductase. PLANT PHYSIOLOGY 2023; 193:2734-2749. [PMID: 37625793 DOI: 10.1093/plphys/kiad474] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/27/2023]
Abstract
Although the sources of molecular hydrogen (H2) synthesis in plants remain to be fully elucidated, ample evidence shows that plant-based H2 can regulate development and stress responses. Here, we present genetic and molecular evidence indicating that nitrate reductase (NR) might be a target of H2 sensing that positively regulates nitrogen use efficiency (NUE) and seed size in Arabidopsis (Arabidopsis thaliana). The expression level of NR and changes of NUE under control and, in particular, low nitrogen supply were positively associated with H2 addition supplied exogenously or through genetic manipulation. The improvement in nitrate assimilation achieved by H2 was also mediated via NR dephosphorylation. H2 control of seed size was impaired by NR mutation. Further genetic evidence revealed that H2, NR, and nitric oxide can synergistically regulate nitrate assimilation in response to N starvation conditions. Collectively, our data indicate that NR might be a target for H2 sensing, ultimately positively regulating nitrate uptake and seed size. These results provide insights into H2 signaling and its functions in plant metabolism.
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Affiliation(s)
- Pengfei Cheng
- College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yueqiao Wang
- College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Chenxu Cai
- College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Longna Li
- College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yan Zeng
- Life Science Group, Air Liquide (China) R&D Co., Ltd., Shanghai 201108, China
| | - Xu Cheng
- Life Science Group, Air Liquide (China) R&D Co., Ltd., Shanghai 201108, China
| | - Wenbiao Shen
- College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
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7
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Baril X, Constant P. Carbon amendments in soil microcosms induce uneven response on H2 oxidation activity and microbial community composition. FEMS Microbiol Ecol 2023; 99:fiad159. [PMID: 38040657 PMCID: PMC10716739 DOI: 10.1093/femsec/fiad159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/27/2023] [Accepted: 11/30/2023] [Indexed: 12/03/2023] Open
Abstract
High-affinity H2-oxidizing bacteria (HA-HOB) thriving in soil are responsible for the most important sink of atmospheric H2. Their activity increases with soil organic carbon content, but the incidence of different carbohydrate fractions on the process has received little attention. Here we tested the hypothesis that carbon amendments impact HA-HOB activity and diversity differentially depending on their recalcitrance and their concentration. Carbon sources (sucrose, starch, cellulose) and application doses (0, 0.1, 1, 3, 5% Ceq soildw-1) were manipulated in soil microcosms. Only 0.1% Ceq soildw-1 cellulose treatment stimulated the HA-HOB activity. Sucrose amendments induced the most significant changes, with an abatement of 50% activity at 1% Ceq soildw-1. This was accompanied with a loss of bacterial and fungal alpha diversity and a reduction of high-affinity group 1 h/5 [NiFe]-hydrogenase gene (hhyL) abundance. A quantitative classification framework was elaborated to assign carbon preference traits to 16S rRNA gene, ITS and hhyL genotypes. The response was uneven at the taxonomic level, making carbon preference a difficult trait to predict. Overall, the results suggest that HA-HOB activity is more susceptible to be stimulated by low doses of recalcitrant carbon, while labile carbon-rich environment is an unfavorable niche for HA-HOB, inducing catabolic repression of hydrogenase.
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Affiliation(s)
- Xavier Baril
- Institut national de la recherche scientifique, Centre Armand-Frappier Santé Biotechnologie, 531 boulevard des Prairies, Laval, Québec H7V 1B7, Canada
| | - Philippe Constant
- Institut national de la recherche scientifique, Centre Armand-Frappier Santé Biotechnologie, 531 boulevard des Prairies, Laval, Québec H7V 1B7, Canada
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8
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Xu Y, Teng Y, Wang X, Ren W, Zhao L, Luo Y, Christie P, Greening C. Endogenous biohydrogen from a rhizobium-legume association drives microbial biodegradation of polychlorinated biphenyl in contaminated soil. ENVIRONMENT INTERNATIONAL 2023; 176:107962. [PMID: 37196568 DOI: 10.1016/j.envint.2023.107962] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 04/11/2023] [Accepted: 05/04/2023] [Indexed: 05/19/2023]
Abstract
Endogenous hydrogen (H2) is produced through rhizobium-legume associations in terrestrial ecosystems worldwide through dinitrogen fixation. In turn, this gas may alter rhizosphere microbial community structure and modulate biogeochemical cycles. However, very little is understood about the role that this H2 leaking to the rhizosphere plays in shaping the persistent organic pollutants degrading microbes in contaminated soils. Here, we combined DNA-stable isotope probing (DNA-SIP) with metagenomics to explore how endogenous H2 from the symbiotic rhizobium-alfalfa association drives the microbial biodegradation of tetrachlorobiphenyl PCB 77 in a contaminated soil. The results showed that PCB77 biodegradation efficiency increased significantly in soils treated with endogenous H2. Based on metagenomes of 13C-enriched DNA fractions, endogenous H2 selected bacteria harboring PCB degradation genes. Functional gene annotation allowed the reconstruction of several complete pathways for PCB catabolism, with different taxa conducting successive metabolic steps of PCB metabolism. The enrichment through endogenous H2 of hydrogenotrophic Pseudomonas and Magnetospirillum encoding biphenyl oxidation genes drove PCB biodegradation. This study proves that endogenous H2 is a significant energy source for active PCB-degrading communities and suggests that elevated H2 can influence the microbial ecology and biogeochemistry of the legume rhizosphere.
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Affiliation(s)
- Yongfeng Xu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Ying Teng
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Xiaomi Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Wenjie Ren
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Ling Zhao
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Yongming Luo
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Peter Christie
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
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Katsyv A, Kumar A, Saura P, Pöverlein MC, Freibert SA, T Stripp S, Jain S, Gamiz-Hernandez AP, Kaila VRI, Müller V, Schuller JM. Molecular Basis of the Electron Bifurcation Mechanism in the [FeFe]-Hydrogenase Complex HydABC. J Am Chem Soc 2023; 145:5696-5709. [PMID: 36811855 PMCID: PMC10021017 DOI: 10.1021/jacs.2c11683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Electron bifurcation is a fundamental energy coupling mechanism widespread in microorganisms that thrive under anoxic conditions. These organisms employ hydrogen to reduce CO2, but the molecular mechanisms have remained enigmatic. The key enzyme responsible for powering these thermodynamically challenging reactions is the electron-bifurcating [FeFe]-hydrogenase HydABC that reduces low-potential ferredoxins (Fd) by oxidizing hydrogen gas (H2). By combining single-particle cryo-electron microscopy (cryoEM) under catalytic turnover conditions with site-directed mutagenesis experiments, functional studies, infrared spectroscopy, and molecular simulations, we show that HydABC from the acetogenic bacteria Acetobacterium woodii and Thermoanaerobacter kivui employ a single flavin mononucleotide (FMN) cofactor to establish electron transfer pathways to the NAD(P)+ and Fd reduction sites by a mechanism that is fundamentally different from classical flavin-based electron bifurcation enzymes. By modulation of the NAD(P)+ binding affinity via reduction of a nearby iron-sulfur cluster, HydABC switches between the exergonic NAD(P)+ reduction and endergonic Fd reduction modes. Our combined findings suggest that the conformational dynamics establish a redox-driven kinetic gate that prevents the backflow of the electrons from the Fd reduction branch toward the FMN site, providing a basis for understanding general mechanistic principles of electron-bifurcating hydrogenases.
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Affiliation(s)
- Alexander Katsyv
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany
| | - Anuj Kumar
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany.,SYNMIKRO Research Center and Department of Chemistry, Philipps-University of Marburg, Marburg 35032, Germany
| | - Patricia Saura
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Maximilian C Pöverlein
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Sven A Freibert
- Institut für Zytobiologie im Zentrum SYNMIKRO, Philipps-University of Marburg, Marburg 35032, Germany.,Core Facility "Protein Biochemistry and Spectroscopy", Marburg 35032, Germany
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin 14195, Germany
| | - Surbhi Jain
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany
| | - Ana P Gamiz-Hernandez
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main 60438, Germany
| | - Jan M Schuller
- SYNMIKRO Research Center and Department of Chemistry, Philipps-University of Marburg, Marburg 35032, Germany
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10
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Chen K, Chen X, Stegen JC, Villa JA, Bohrer G, Song X, Chang KY, Kaufman M, Liang X, Guo Z, Roden EE, Zheng C. Vertical Hydrologic Exchange Flows Control Methane Emissions from Riverbed Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:4014-4026. [PMID: 36811826 DOI: 10.1021/acs.est.2c07676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
CH4 emissions from inland waters are highly uncertain in the current global CH4 budget, especially for streams, rivers, and other lotic systems. Previous studies have attributed the strong spatiotemporal heterogeneity of riverine CH4 to environmental factors such as sediment type, water level, temperature, or particulate organic carbon abundance through correlation analysis. However, a mechanistic understanding of the basis for such heterogeneity is lacking. Here, we combine sediment CH4 data from the Hanford reach of the Columbia River with a biogeochemical-transport model to show that vertical hydrologic exchange flows (VHEFs), driven by the difference between river stage and groundwater level, determine CH4 flux at the sediment-water interface. CH4 fluxes show a nonlinear relationship with the magnitude of VHEFs, where high VHEFs introduce O2 into riverbed sediments, which inhibit CH4 production and induce CH4 oxidation, and low VHEFs cause transient reduction in CH4 flux (relative to production) due to reduced advective CH4 transport. In addition, VHEFs lead to the hysteresis of temperature rise and CH4 emissions because high river discharge caused by snowmelt in spring leads to strong downwelling flow that offsets increasing CH4 production with temperature rise. Our findings reveal how the interplay between in-stream hydrologic flux besides fluvial-wetland connectivity and microbial metabolic pathways that compete with methanogenic pathways can produce complex patterns in CH4 production and emission in riverbed alluvial sediments.
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Affiliation(s)
- Kewei Chen
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xingyuan Chen
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - James C Stegen
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Jorge A Villa
- School of Geosciences, University of Louisiana at Lafayette, Lafayette, Louisiana 70506, United States
| | - Gil Bohrer
- Department of Civil, Environmental and Geodetic Engineering, Ohio State University, Columbus, Ohio 43210, United States
| | - Xuehang Song
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Kuang-Yu Chang
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Matthew Kaufman
- Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Xiuyu Liang
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhiling Guo
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Eric E Roden
- Department of Geoscience, University of Wisconsin, Madison, Wisconsin 53706, United States
| | - Chunmiao Zheng
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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11
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Magotra VK, Lee DJ, Kim DY, Lee SJ, Kang TW, Magotra A, Inamdar AI, Shrestha NK, Patil SA, Thammanu S, Jeon HC. Increasing power generation to a single-chamber compost soil urea fuel cell for carbon-neutral bioelectricity generation: A novel approach. Front Microbiol 2023; 14:1086962. [PMID: 36876058 PMCID: PMC9983554 DOI: 10.3389/fmicb.2023.1086962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/16/2023] [Indexed: 02/19/2023] Open
Abstract
Microbial fuel cells (CS-UFC) utilize waste resources containing biodegradable materials that play an essential role in green energy. MFC technology generates "carbon-neutral" bioelectricity and involves a multidisciplinary approach to microbiology. MFCs will play an important role in the harvesting of "green electricity." In this study, a single-chamber urea fuel cell is fabricated that uses these different wastewaters as fuel to generate power. Soil has been used to generate electrical power in microbial fuel cells and exhibited several potential applications to optimize the device; the urea fuel concentration is varied from 0.1 to 0.5 g/mL in a single-chamber compost soil urea fuel cell (CS-UFC). The proposed CS-UFC has a high power density and is suitable for cleaning chemical waste, such as urea, as it generates power by consuming urea-rich waste as fuel. The CS-UFC generates 12 times higher power than conventional fuel cells and exhibits size-dependent behavior. The power generation increases with a shift from the coin cell toward the bulk size. The power density of the CS-UFC is 55.26 mW/m2. This result confirmed that urea fuel significantly affects the power generation of single-chamber CS-UFC. This study aimed to reveal the effect of soil properties on the generated electric power from soil processes using waste, such as urea, urine, and industrial-rich wastewater as fuel. The proposed system is suitable for cleaning chemical waste; moreover, the proposed CS-UFC is a novel, sustainable, cheap, and eco-friendly design system for soil-based bulk-type design for large-scale urea fuel cell applications.
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Affiliation(s)
- Verjesh Kumar Magotra
- Quantum-Functional Semiconductor Research Center, Dongguk University, Seoul, Republic of Korea
| | - Dong-Jin Lee
- Quantum-Functional Semiconductor Research Center, Dongguk University, Seoul, Republic of Korea
| | - D Y Kim
- Quantum-Functional Semiconductor Research Center, Dongguk University, Seoul, Republic of Korea
| | - S J Lee
- Quantum-Functional Semiconductor Research Center, Dongguk University, Seoul, Republic of Korea
| | - T W Kang
- Quantum-Functional Semiconductor Research Center, Dongguk University, Seoul, Republic of Korea
| | - Arjun Magotra
- Department of Computer Science and Engineering, Dongguk University, Seoul, Republic of Korea
| | - Akbar I Inamdar
- Division of Physics and Semiconductor Science, Dongguk University, Seoul, Republic of Korea
| | - Nabeen K Shrestha
- Division of Physics and Semiconductor Science, Dongguk University, Seoul, Republic of Korea.,Department of Nano Technology and Advanced Materials Engineering, Sejong University, Seoul, Republic of Korea
| | - Supriya A Patil
- Department of Nano Technology and Advanced Materials Engineering, Sejong University, Seoul, Republic of Korea
| | | | - Hee Chang Jeon
- Quantum-Functional Semiconductor Research Center, Dongguk University, Seoul, Republic of Korea
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12
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Meinel M, Delgado AG, Ilhan ZE, Aguero ML, Aguiar S, Krajmalnik-Brown R, Torres CI. Organic carbon metabolism is a main determinant of hydrogen demand and dynamics in anaerobic soils. CHEMOSPHERE 2022; 303:134877. [PMID: 35577129 DOI: 10.1016/j.chemosphere.2022.134877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/29/2022] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
Hydrogen (H2) is a crucial electron donor for many processes in the environment including nitrate-, sulfate- and, iron-reduction, homoacetogenesis, and methanogenesis, and is a major determinant of microbial competition and metabolic pathways in groundwater, sediments, and soils. Despite the importance of H2 for many microbial processes in the environment, the total H2 consuming capacity (or H2 demand) of soils is generally unknown. Using soil microcosms with added H2, the aims of this study were 1) to measure the H2 demand of geochemically diverse soils and 2) to define the processes leading to this demand. Study results documented a large range of H2 demand in soil (0.034-1.2 millielectron equivalents H2 g-1 soil). The measured H2 demand greatly exceeded the theoretical demand predicted based on measured concentrations of common electron acceptors initially present in a library of 15 soils. While methanogenesis accounted for the largest fraction of H2 demand, humic acid reduction and acetogenesis were also significant contributing H2-consuming processes. Much of the H2 demand could be attributed to CO2 produced during incubation from fermentation and/or acetoclastic methanogenesis. The soil initial total organic carbon showed the strongest correlation to H2 demand. Besides external additions, H2 was likely generated or cycled in the microcosms. Apart from fermentative H2 production, carboxylate elongation to produce C4-C7 fatty acids may have accounted for additional H2 production in these soils. Many of these processes, especially the organic carbon contribution is underestimated in microbial models for H2 consumption in natural soil ecosystems or during bioremediation of contaminants in soils.
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Affiliation(s)
- Megan Meinel
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, School of Sustainable Engineering and the Built Environment, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA
| | - Anca G Delgado
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, School of Sustainable Engineering and the Built Environment, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA
| | - Zehra Esra Ilhan
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA
| | - Marisol Luna Aguero
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, School of Sustainable Engineering and the Built Environment, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA
| | - Samuel Aguiar
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA
| | - Rosa Krajmalnik-Brown
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, School of Sustainable Engineering and the Built Environment, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Biodesign Center for Health Through Microbiomes, 1001 S McAllister Ave, Tempe, AZ, USA.
| | - César I Torres
- Arizona State University, Biodesign Swette Center for Environmental Biotechnology, 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, Engineering Research Center for Bio-mediated and Bio-inspired Geotechnics (CBBG), 1001 S McAllister Ave, Tempe, AZ, USA; Arizona State University, School for Engineering of Matter, Transport & Energy, 1001 S McAllister Ave, Tempe, AZ, USA.
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13
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Zhang C, Atashgahi S, Bosma TNP, Peng P, Smidt H. Organohalide respiration potential in marine sediments from Aarhus Bay. FEMS Microbiol Ecol 2022; 98:6605901. [PMID: 35689665 PMCID: PMC9303371 DOI: 10.1093/femsec/fiac073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 05/09/2022] [Accepted: 06/08/2022] [Indexed: 11/14/2022] Open
Abstract
Organohalide respiration (OHR), catalysed by reductive dehalogenases (RDases), plays an important role in halogen cycling. Natural organohalides and putative RDase-encoding genes have been reported in Aarhus Bay sediments, however, OHR has not been experimentally verified. Here we show that sediments of Aarhus Bay can dehalogenate a range of organohalides, and different organohalides differentially affected microbial community compositions. PCE-dechlorinating cultures were further examined by 16S rRNA gene-targeted quantitative PCR and amplicon sequencing. Known organohalide-respiring bacteria (OHRB) including Dehalococcoides, Dehalobacter and Desulfitobacterium decreased in abundance during transfers and serial dilutions, suggesting the importance of yet uncharacterized OHRB in these cultures. Switching from PCE to 2,6-DBP led to its complete debromination to phenol in cultures with and without sulfate. 2,6-DBP debrominating cultures differed in microbial composition from PCE-dechlorinating cultures. Desulfobacterota genera recently verified to include OHRB, including Desulfovibrio and Desulfuromusa, were enriched in all microcosms, whereas Halodesulfovibrio was only enriched in cultures without sulfate. Hydrogen and methane were detected in cultures without sulfate. Hydrogen likely served as electron donor for OHR and methanogenesis. This study shows that OHR can occur in marine environments mediated by yet unknown OHRB, suggesting their role in natural halogen cycling.
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Affiliation(s)
- Chen Zhang
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.,Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
| | - Siavash Atashgahi
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Tom N P Bosma
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Peng Peng
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.,Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan 48109-2125, United States
| | - Hauke Smidt
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
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14
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An Accurate Model for Estimating H2 Solubility in Pure Water and Aqueous NaCl Solutions. ENERGIES 2022. [DOI: 10.3390/en15145021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
By employing a specific particle interaction theory and a high-precision equation of states for the liquid and vapor phases of H2, respectively, a new H2 solubility model in pure water and aqueous NaCl solutions is proposed in this study. The model established by fitting the experimental data of H2 solubility can be used to estimate H2 solubility in pure water at temperatures and pressures of 273.15–423.15 K and 0–1100 bar, respectively, and in salt solutions (NaCl concentration = 0–5 mol/kg) at temperatures and pressures of 273.15–373.15 K and 0–230 bar, respectively. By adopting the theory of liquid electrolyte solutions, the model can also be used to predict H2 solubility in seawater without fitting the experimental data of a seawater system. Within or close to experimental data uncertainty, the mean absolute percentage error between the model-predicted and experimentally obtained H2 solubilities was less than 1.14%.
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15
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Phylogenomic Analysis of Metagenome-Assembled Genomes Deciphered Novel Acetogenic Nitrogen-Fixing Bathyarchaeota from Hot Spring Sediments. Microbiol Spectr 2022; 10:e0035222. [PMID: 35647693 PMCID: PMC9241837 DOI: 10.1128/spectrum.00352-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study describes the phylogenomic analysis and metabolic insights of metagenome-assembled genomes (MAGs) retrieved from hot spring sediment samples. The metagenome-assembled sequences recovered three near-complete genomes belonging to the archaeal phylum. Analysis of genome-wide core genes and 16S rRNA-based phylogeny placed the ILS200 and ILS300 genomes within the uncultivated and largely understudied bathyarchaeal phylum, whereas ILS100 represented the phylum Thaumarchaeota. The average nucleotide identity (ANI) of the bin ILS100 was 76% with Nitrososphaeria_archaeon_isolate_SpSt-1069. However, the bins ILS200 and ILS300 showed ANI values of 75% and 70% with Candidatus_Bathyarchaeota_archaeon_isolate_DRTY-6_2_bin_115 and Candidatus_Bathyarchaeota_archaeon_BA1_ba1_01, respectively. The genomic potential of Bathyarchaeota bins ILS200 and ILS300 showed genes necessary for the Wood-Ljungdahl pathway, and the gene encoding the methyl coenzyme M reductase (mcr) complex essential for methanogenesis was absent. The metabolic potential of the assembled genomes included genes involved in nitrogen assimilation, including nitrogenase and the genes necessary for the urea cycle. The presence of these genes suggested the metabolic potential of Bathyarchaeota to fix nitrogen under extreme environments. In addition, the ILS200 and ILS300 genomes carried genes involved in the tricarboxylic acid (TCA) cycle, glycolysis, and degradation of organic carbons. Finally, we conclude that the reconstructed Bathyarchaeota bins are autotrophic acetogens and organo-heterotrophs. IMPORTANCE We describe the Bathyarchaeota bins that are likely to be acetogens with a wide range of metabolic potential. These bins did not exhibit methanogenic machinery, suggesting methane production may not occur by all subgroup lineages of Bathyarchaeota. Phylogenetic analysis support that both ILS200 and ILS300 belonged to the Bathyarchaeota. The discovery of new bathyarchaeotal MAGs provides additional knowledge for understanding global carbon and nitrogen metabolism under extreme conditions.
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16
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Buzzard V, Thorne D, Gil-Loaiza J, Cueva A, Meredith LK. Sensitivity of soil hydrogen uptake to natural and managed moisture dynamics in a semiarid urban ecosystem. PeerJ 2022; 10:e12966. [PMID: 35317075 PMCID: PMC8934528 DOI: 10.7717/peerj.12966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 01/28/2022] [Indexed: 01/11/2023] Open
Abstract
The North American Monsoon season (June-September) in the Sonoran Desert brings thunderstorms and heavy rainfall. These rains bring cooler temperature and account for roughly half of the annual precipitation making them important for biogeochemical processes. The intensity of the monsoon rains also increase flooding in urban areas and rely on green infrastructure (GI) stormwater management techniques such as water harvesting and urban rain gardens to capture runoff. The combination of increased water availability during the monsoon and water management provide a broad moisture regime for testing responses in microbial metabolism to natural and managed soil moisture pulses in drylands. Soil microbes rely on atmospheric hydrogen (H2) as an important energy source in arid and semiarid landscapes with low soil moisture and carbon availability. Unlike mesic ecosystems, transient water availability in arid and semiarid ecosystems has been identified as a key limiting driver of microbe-mediated H2 uptake. We measured soil H2 uptake in rain gardens exposed to three commonly used water harvesting practices during the monsoon season in Tucson AZ, USA. In situ static chamber measurements were used to calculate H2 uptake in each of the three water harvesting treatments passive (stormwater runoff), active (stored rooftop runoff), and greywater (used laundry water) compared to an unaltered control treatment to assess the effects of water management practices on soil microbial activity. In addition, soils were collected from each treatment and brought to the lab for an incubation experiment manipulating the soil moisture to three levels capturing the range observed from field samples. H2 fluxes from all treatments ranged between -0.72 nmol m-2 s-1 and -3.98 nmol m-2 s-1 over the monsoon season. Soil H2 uptake in the greywater treatment was on average 53% greater than the other treatments during pre-monsoon, suggesting that the increased frequency and availability of water in the greywater treatment resulted in higher H2 uptake during the dry season. H2 uptake was significantly correlated with soil moisture (r = -0.393, p = 0.001, df = 62) and temperature (r = 0.345, p = 0.005, df = 62). Our findings suggest that GI managed residential soils can maintain low levels of H2 uptake during dry periods, unlike unmanaged systems. The more continuous H2 uptake associated with GI may help reduce the impacts of drought on H2 cycling in semiarid urban ecosystems.
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Affiliation(s)
- Vanessa Buzzard
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, United States
| | - Dana Thorne
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, United States
| | - Juliana Gil-Loaiza
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, United States
| | - Alejandro Cueva
- Biosphere2, University of Arizona, Oracle, Arizona, United States
| | - Laura K. Meredith
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, United States,BIO5 Institute, University of Arizona, Tucson, Arizona, United States
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17
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Morra S. Fantastic [FeFe]-Hydrogenases and Where to Find Them. Front Microbiol 2022; 13:853626. [PMID: 35308355 PMCID: PMC8924675 DOI: 10.3389/fmicb.2022.853626] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 02/10/2022] [Indexed: 01/01/2023] Open
Abstract
[FeFe]-hydrogenases are complex metalloenzymes, key to microbial energy metabolism in numerous organisms. During anaerobic metabolism, they dissipate excess reducing equivalents by using protons from water as terminal electron acceptors, leading to hydrogen production. This reaction is coupled to reoxidation of specific redox partners [ferredoxins, NAD(P)H or cytochrome c3], that can be used either individually or simultaneously (via flavin-based electron bifurcation). [FeFe]-hydrogenases also serve additional physiological functions such as H2 uptake (oxidation), H2 sensing, and CO2 fixation. This broad functional spectrum is enabled by a modular architecture and vast genetic diversity, which is not fully explored and understood. This Mini Review summarises recent advancements in identifying and characterising novel [FeFe]-hydrogenases, which has led to expanding our understanding of their multiple roles in metabolism and functional mechanisms. For example, while numerous well-known [FeFe]-hydrogenases are irreversibly damaged by oxygen, some newly discovered enzymes display intrinsic tolerance. These findings demonstrate that oxygen sensitivity varies between different [FeFe]-hydrogenases: in some cases, protection requires the presence of exogenous compounds such as carbon monoxide or sulphide, while in other cases it is a spontaneous built-in mechanism that relies on a reversible conformational change. Overall, it emerges that additional research is needed to characterise new [FeFe]-hydrogenases as this will reveal further details on the physiology and mechanisms of these enzymes that will enable potential impactful applications.
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Affiliation(s)
- Simone Morra
- Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
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18
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Cowan DA, Ferrari BC, McKay CP. Out of Thin Air? Astrobiology and Atmospheric Chemotrophy. ASTROBIOLOGY 2022; 22:225-232. [PMID: 35025628 PMCID: PMC8861918 DOI: 10.1089/ast.2021.0066] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The emerging understanding of microbial trace gas chemotrophy as a metabolic strategy to support energy and carbon acquisition for microbial survival and growth has significant implications in the search for past, and even extant, life beyond Earth. The use of trace gases, including hydrogen and carbon monoxide as substrates for microbial oxidation, potentially offers a viable strategy with which to support life on planetary bodies that possess a suitable atmospheric composition, such as Mars and Titan. Here, we discuss the current state of knowledge of this process and explore its potential in the field of astrobiological exploration.
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Affiliation(s)
- Don A. Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Address correspondence to: Don A. Cowan, Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Building NW2, Room 3-12, Hatfield Campus, Lynnwood Road, Pretoria 0002, South Africa
| | - Belinda C. Ferrari
- School of Biotechnology and Biomolecular Sciences, Australian Centre for Astrobiology, UNSW Sydney, Randwick, Australia
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19
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Meredith LK, Tfaily MM. Capturing the microbial volatilome: an oft overlooked 'ome'. Trends Microbiol 2022; 30:622-631. [PMID: 35039213 DOI: 10.1016/j.tim.2021.12.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/03/2021] [Accepted: 12/08/2021] [Indexed: 11/26/2022]
Abstract
Among the diverse metabolites produced by microbial communities, some are volatile. Volatile organic compounds (VOCs) are vigorously cycled by microbes as metabolic substrates and products and as signaling molecules. Yet, current microbial metabolomic studies predominantly focus on nonvolatile metabolites and overlook VOCs, which therefore represent a missing component of the metabolome. Advances in VOC detection now allow simultaneous observation of the numerous VOCs constituting the 'volatilome' of microbial systems. We present a roadmap for integrating and advancing VOC and other 'omics approaches and highlight the potential for realtime VOC measurements to help overcome limitations in discrete 'omics sampling. Including volatile metabolites in metabolomics, both conceptually and in practice, will build a more comprehensive understanding of microbial processes across ecological communities.
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Affiliation(s)
- Laura K Meredith
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA; BIO5 Institute, University of Arizona, Tucson, AZ, USA.
| | - Malak M Tfaily
- BIO5 Institute, University of Arizona, Tucson, AZ, USA; Department of Environmental Science, University of Arizona, Tucson, AZ, USA.
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20
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Sharifi R, Jeon JS, Ryu CM. Belowground plant-microbe communications via volatile compounds. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:463-486. [PMID: 34727189 DOI: 10.1093/jxb/erab465] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 10/21/2021] [Indexed: 06/13/2023]
Abstract
Volatile compounds play important roles in rhizosphere biological communications and interactions. The emission of plant and microbial volatiles is a dynamic phenomenon that is affected by several endogenous and exogenous signals. Diffusion of volatiles can be limited by their adsorption, degradation, and dissolution under specific environmental conditions. Therefore, rhizosphere volatiles need to be investigated on a micro and spatiotemporal scale. Plant and microbial volatiles can expand and specialize the rhizobacterial niche not only by improving the root system architecture such that it serves as a nutrient-rich shelter, but also by inhibiting or promoting the growth, chemotaxis, survival, and robustness of neighboring organisms. Root volatiles play an important role in engineering the belowground microbiome by shaping the microbial community structure and recruiting beneficial microbes. Microbial volatiles are appropriate candidates for improving plant growth and health during environmental challenges and climate change. However, some technical and experimental challenges limit the non-destructive monitoring of volatile emissions in the rhizosphere in real-time. In this review, we attempt to clarify the volatile-mediated intra- and inter-kingdom communications in the rhizosphere, and propose improvements in experimental design for future research.
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Affiliation(s)
- Rouhallah Sharifi
- Department of Plant Protection, College of Agriculture and Natural Resources, Razi University, Kermanshah, Iran
| | - Je-Seung Jeon
- Molecular Phytobacteriology Laboratory, Infectious Disease Research Center, KRIBB, Daejeon 34141, South Korea
| | - Choong-Min Ryu
- Molecular Phytobacteriology Laboratory, Infectious Disease Research Center, KRIBB, Daejeon 34141, South Korea
- Biosystem and Bioengineering Program, University of Science and Technology (UST), Daejeon 34141, South Korea
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21
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Genome Sequence of a Thermoacidophilic Methanotroph Belonging to the Verrucomicrobiota Phylum from Geothermal Hot Springs in Yellowstone National Park: A Metagenomic Assembly and Reconstruction. Microorganisms 2022; 10:microorganisms10010142. [PMID: 35056591 PMCID: PMC8779874 DOI: 10.3390/microorganisms10010142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/23/2021] [Accepted: 01/07/2022] [Indexed: 02/04/2023] Open
Abstract
Verrucomicrobiotal methanotrophs are thermoacidophilic methane oxidizers that have been isolated from volcanic and geothermal regions of the world. We used a metagenomic approach that entailed obtaining the whole genome sequence of a verrucomicrobiotal methanotroph from a microbial consortium enriched from samples obtained from Nymph Lake (89.9 °C, pH 2.73) in Yellowstone National Park in the USA. To identify and reconstruct the verrucomicrobiotal genome from Illumina NovaSeq 6000 sequencing data, we constructed a bioinformatic pipeline with various combinations of de novo assembly, alignment, and binning algorithms. Based on the marker gene (pmoA), we identified and assembled the Candidatus Methylacidiphilum sp. YNP IV genome (2.47 Mbp, 2392 ORF, and 41.26% GC content). In a comparison of average nucleotide identity between Ca. Methylacidiphilum sp. YNP IV and Ca. Methylacidiphilum fumariolicum SolV, its closest 16S rRNA gene sequence relative, is lower than 95%, suggesting that Ca. Methylacidiphilum sp. YNP IV can be regarded as a different species. The Ca. Methylacidiphilum sp. YNP IV genome assembly showed most of the key genes for methane metabolism, the CBB pathway for CO2 fixation, nitrogen fixation and assimilation, hydrogenases, and rare earth elements transporter, as well as defense mechanisms. The assembly and reconstruction of a thermoacidophilic methanotroph belonging to the Verrucomicrobiota phylum from a geothermal environment adds further evidence and knowledge concerning the diversity of biological methane oxidation and on the adaptation of this geochemically relevant reaction in extreme environments.
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Abstract
Improvements in the growth, yield, and quality of horticultural crops require the development of simply integrated, cost-efficient, and eco-friendly solutions. Hydrogen gas (H2) has been observed to have fertilization effects on soils by influencing rhizospheric microorganisms, resulting in improvements in crop yield and quality. Ample studies have shown that H2 has positive effects on horticultural crops, such as promoting root development, enhancing tolerance against abiotic and biotic stress, prolonging storage life, and improving postharvest quality of fruits, vegetables and cut flowers. In this review, we aim to evaluate the feasibility of molecular hydrogen application in horticulture and the strategies for its application, including H2 delivery methods, treatment timing, and the concentration of H2 applied. The discussion will be accompanied by outlining the effects of H2 and the likely mechanisms of its efficacy. In short, the application of H2 may provide novel opportunities for simple and cost efficient improvements of horticultural production in terms of increased yield and product quality but with low carbon dioxide emissions.
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23
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Hancock JT, LeBaron TW, May J, Thomas A, Russell G. Molecular Hydrogen: Is This a Viable New Treatment for Plants in the UK? PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112270. [PMID: 34834633 PMCID: PMC8618766 DOI: 10.3390/plants10112270] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/07/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Despite being trialed in other regions of the world, the use of molecular hydrogen (H2) for enhanced plant growth and the postharvest storage of crops has yet to be widely accepted in the UK. The evidence that the treatment of plants and plant products with H2 alleviates plant stress and slows crop senescence continues to grow. Many of these effects appear to be mediated by the alteration of the antioxidant capacity of plant cells. Some effects seem to involve heme oxygenase, whilst the reduction in the prosthetic group Fe3+ is also suggested as a mechanism. Although it is difficult to use as a gaseous treatment in a field setting, the use of hydrogen-rich water (HRW) has the potential to be of significant benefit to agricultural practices. However, the use of H2 in agriculture will only be adopted if the benefits outweigh the production and application costs. HRW is safe and relatively easy to use. If H2 gas or HRW are utilized in other countries for agricultural purposes, it is tempting to suggest that they could also be widely used in the UK in the future, particularly for postharvest storage, thus reducing food waste.
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Affiliation(s)
- John T. Hancock
- Department of Applied Sciences, University of the West of England, Bristol BS16 1QY, UK; (J.M.); (A.T.); (G.R.)
| | - Tyler W. LeBaron
- Centre of Experimental Medicine, Institute for Heart Research, Slovak Academy of Sciences, Faculty of Natural Sciences of Comenius University, 84104 Bratislava, Slovakia;
- Molecular Hydrogen Institute, Enoch, UT 84721, USA
- Department of Kinesiology and Outdoor Recreation, Southern Utah University, Cedar City, UT 84720, USA
| | - Jennifer May
- Department of Applied Sciences, University of the West of England, Bristol BS16 1QY, UK; (J.M.); (A.T.); (G.R.)
| | - Adam Thomas
- Department of Applied Sciences, University of the West of England, Bristol BS16 1QY, UK; (J.M.); (A.T.); (G.R.)
| | - Grace Russell
- Department of Applied Sciences, University of the West of England, Bristol BS16 1QY, UK; (J.M.); (A.T.); (G.R.)
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24
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Hughes ER, Winter MG, Alves da Silva L, Muramatsu MK, Jimenez AG, Gillis CC, Spiga L, Chanin RB, Santos RL, Zhu W, Winter SE. Reshaping of bacterial molecular hydrogen metabolism contributes to the outgrowth of commensal E. coli during gut inflammation. eLife 2021; 10:e58609. [PMID: 34085924 PMCID: PMC8177889 DOI: 10.7554/elife.58609] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 05/20/2021] [Indexed: 12/24/2022] Open
Abstract
The composition of gut-associated microbial communities changes during intestinal inflammation, including an expansion of Enterobacteriaceae populations. The mechanisms underlying microbiota changes during inflammation are incompletely understood. Here, we analyzed previously published metagenomic datasets with a focus on microbial hydrogen metabolism. The bacterial genomes in the inflamed murine gut and in patients with inflammatory bowel disease contained more genes encoding predicted hydrogen-utilizing hydrogenases compared to communities found under non-inflamed conditions. To validate these findings, we investigated hydrogen metabolism of Escherichia coli, a representative Enterobacteriaceae, in mouse models of colitis. E. coli mutants lacking hydrogenase-1 and hydrogenase-2 displayed decreased fitness during colonization of the inflamed cecum and colon. Utilization of molecular hydrogen was in part dependent on respiration of inflammation-derived electron acceptors. This work highlights the contribution of hydrogenases to alterations of the gut microbiota in the context of non-infectious colitis.
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Affiliation(s)
| | - Maria G Winter
- Department of Microbiology, UT SouthwesternDallasUnited States
| | - Laice Alves da Silva
- Departamento de Clinica e Cirurgia Veterinarias, Escola de Veterinaria, Universidade Federal de Minas GeraisBelo HorizonteBrazil
| | | | - Angel G Jimenez
- Department of Microbiology, UT SouthwesternDallasUnited States
| | | | - Luisella Spiga
- Department of Microbiology, UT SouthwesternDallasUnited States
| | | | - Renato L Santos
- Departamento de Clinica e Cirurgia Veterinarias, Escola de Veterinaria, Universidade Federal de Minas GeraisBelo HorizonteBrazil
| | - Wenhan Zhu
- Department of Microbiology, UT SouthwesternDallasUnited States
| | - Sebastian E Winter
- Department of Microbiology, UT SouthwesternDallasUnited States
- Department of Immunology, UT SouthwesternDallasUnited States
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25
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Xu Y, Teng Y, Wang X, Li R, Christie P. Exploring bacterial community structure and function associated with polychlorinated biphenyl biodegradation in two hydrogen-amended soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 745:140839. [PMID: 32726695 DOI: 10.1016/j.scitotenv.2020.140839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/07/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Hydrogen (H2) is a universal energy source supplying survival energy for numerous microbial functions. Diffusive fluxes of H2 released by rhizobacterial symbiont nodules in which H2 is an obligate by-product of dinitrogen fixation may act as an additional energy input shaping microbial community structure and function in soils. However, the effects of H2 at the soil-nodule interface on soil contaminant degradation processes are poorly understood. Here, we mimicked the hydrogen conditions present at the soil-nodule interface (10,000 ppmv) to test the impact of elevated H2 concentrations on soil microbial removal of 3, 3', 4, 4'-tetrachlorobiphenyl (PCB77) and examined the associated bacterial communities and their functions by conducting a microcosm experiment using two different soil types at three PCB contamination levels (0.5, 1.0 and 5.0 mg kg-1). After incubation for 84 days the PCB77 removal rates in the elevated H2 treatments in the Paddy soil were significantly promoted (by 4.88 to 6.41%) compared with the control (0.5 ppmv H2) but no significant effect was observed in a Fluvo-aquic soil. This is consistent with changes in the abundance of functional genes for PCB-degraders as shown by quantitative real-time PCR (Q-PCR) and phylogenetic investigation of bacterial communities by reconstruction of unobserved states (PICRUSt). 16S amplicon sequencing was conducted to explore bacterial community structure and correlate the genera to potential PCB degradation. The abundance of a total of four potentially PCB-degrading bacterial genera (Bacillus, Streptomyces, Ramlibacter and Paenibacillus) increased with increasing H2 level. In addition, the abundance of hydrogenase in the elevated H2 treatments was higher than in the control across different contamination levels in both soil types. Thus, elevated H2 stimulated soil PCB degradation with direct effects (aerobic PCB-degrading bacteria directly utilized H2 as an energy source for growth and thus enhanced PCB degradation efficiency) and indirect effects (aerobic PCB-degrading bacteria acted synergistically with other hydrogenotrophs to enhance PCB degradation efficiency by exchange of substances and energy). These results help to further understand the role of elevated hydrogen amendment in the PCB biodegradation process and provide evidence that H2 supports metabolic and energetic flexibility in microorganisms supplying a range of ecosystem services.
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Affiliation(s)
- Yongfeng Xu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of the Chinese Academy of Sciences, Beijing, China
| | - Ying Teng
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Xiaomi Wang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Ran Li
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of the Chinese Academy of Sciences, Beijing, China
| | - Peter Christie
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
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26
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Giguere AT, Eichorst SA, Meier DV, Herbold CW, Richter A, Greening C, Woebken D. Acidobacteria are active and abundant members of diverse atmospheric H 2-oxidizing communities detected in temperate soils. ISME JOURNAL 2020; 15:363-376. [PMID: 33024291 PMCID: PMC8027828 DOI: 10.1038/s41396-020-00750-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/30/2020] [Accepted: 08/12/2020] [Indexed: 12/24/2022]
Abstract
Significant rates of atmospheric dihydrogen (H2) consumption have been observed in temperate soils due to the activity of high-affinity enzymes, such as the group 1h [NiFe]-hydrogenase. We designed broadly inclusive primers targeting the large subunit gene (hhyL) of group 1h [NiFe]-hydrogenases for long-read sequencing to explore its taxonomic distribution across soils. This approach revealed a diverse collection of microorganisms harboring hhyL, including previously unknown groups and taxonomically not assignable sequences. Acidobacterial group 1h [NiFe]-hydrogenase genes were abundant and expressed in temperate soils. To support the participation of acidobacteria in H2 consumption, we studied two representative mesophilic soil acidobacteria, which expressed group 1h [NiFe]-hydrogenases and consumed atmospheric H2 during carbon starvation. This is the first time mesophilic acidobacteria, which are abundant in ubiquitous temperate soils, have been shown to oxidize H2 down to below atmospheric concentrations. As this physiology allows bacteria to survive periods of carbon starvation, it could explain the success of soil acidobacteria. With our long-read sequencing approach of group 1h [NiFe]-hydrogenase genes, we show that the ability to oxidize atmospheric levels of H2 is more widely distributed among soil bacteria than previously recognized and could represent a common mechanism enabling bacteria to persist during periods of carbon deprivation.
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Affiliation(s)
- Andrew T Giguere
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.,Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Stephanie A Eichorst
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.
| | - Dimitri V Meier
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Craig W Herbold
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Andreas Richter
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.,School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Dagmar Woebken
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
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27
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Farhan Ul Haque M, Xu HJ, Murrell JC, Crombie A. Facultative methanotrophs - diversity, genetics, molecular ecology and biotechnological potential: a mini-review. MICROBIOLOGY (READING, ENGLAND) 2020; 166:894-908. [PMID: 33085587 PMCID: PMC7660913 DOI: 10.1099/mic.0.000977] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/20/2020] [Indexed: 12/18/2022]
Abstract
Methane-oxidizing bacteria (methanotrophs) play a vital role in reducing atmospheric methane emissions, and hence mitigating their potent global warming effects. A significant proportion of the methane released is thermogenic natural gas, containing associated short-chain alkanes as well as methane. It was one hundred years following the description of methanotrophs that facultative strains were discovered and validly described. These can use some multi-carbon compounds in addition to methane, often small organic acids, such as acetate, or ethanol, although Methylocella strains can also use short-chain alkanes, presumably deriving a competitive advantage from this metabolic versatility. Here, we review the diversity and molecular ecology of facultative methanotrophs. We discuss the genetic potential of the known strains and outline the consequent benefits they may obtain. Finally, we review the biotechnological promise of these fascinating microbes.
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Affiliation(s)
| | - Hui-Juan Xu
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
- Present address: Joint Institute for Environmental Research & Education, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China
| | - J. Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Andrew Crombie
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
- Present address: School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
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28
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Ray AE, Zhang E, Terauds A, Ji M, Kong W, Ferrari BC. Soil Microbiomes With the Genetic Capacity for Atmospheric Chemosynthesis Are Widespread Across the Poles and Are Associated With Moisture, Carbon, and Nitrogen Limitation. Front Microbiol 2020; 11:1936. [PMID: 32903524 PMCID: PMC7437527 DOI: 10.3389/fmicb.2020.01936] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 07/22/2020] [Indexed: 11/13/2022] Open
Abstract
Soil microbiomes within oligotrophic cold deserts are extraordinarily diverse. Increasingly, oligotrophic sites with low levels of phototrophic primary producers are reported, leading researchers to question their carbon and energy sources. A novel microbial carbon fixation process termed atmospheric chemosynthesis recently filled this gap as it was shown to be supporting primary production at two Eastern Antarctic deserts. Atmospheric chemosynthesis uses energy liberated from the oxidation of atmospheric hydrogen to drive the Calvin-Benson-Bassham (CBB) cycle through a new chemotrophic form of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), designated IE. Here, we propose that the genetic determinants of this process; RuBisCO type IE (rbcL1E) and high affinity group 1h-[NiFe]-hydrogenase (hhyL) are widespread across cold desert soils and that this process is linked to dry and nutrient-poor environments. We used quantitative PCR (qPCR) to quantify these genes in 122 soil microbiomes across the three poles; spanning the Tibetan Plateau, 10 Antarctic and three high Arctic sites. Both genes were ubiquitous, being present at variable abundances in all 122 soils examined (rbcL1E, 6.25 × 103–1.66 × 109 copies/g soil; hhyL, 6.84 × 103–5.07 × 108 copies/g soil). For the Antarctic and Arctic sites, random forest and correlation analysis against 26 measured soil physicochemical parameters revealed that rbcL1E and hhyL genes were associated with lower soil moisture, carbon and nitrogen content. While further studies are required to quantify the rates of trace gas carbon fixation and the organisms involved, we highlight the global potential of desert soil microbiomes to be supported by this new minimalistic mode of carbon fixation, particularly throughout dry oligotrophic environments, which encompass more than 35% of the Earth’s surface.
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Affiliation(s)
- Angelique E Ray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Eden Zhang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Aleks Terauds
- Australian Antarctic Division, Department of Environment, Antarctic Conservation and Management, Kingston, TAS, Australia
| | - Mukan Ji
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Weidong Kong
- Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Belinda C Ferrari
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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29
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Hakobyan A, Zhu J, Glatter T, Paczia N, Liesack W. Hydrogen utilization by Methylocystis sp. strain SC2 expands the known metabolic versatility of type IIa methanotrophs. Metab Eng 2020; 61:181-196. [PMID: 32479801 DOI: 10.1016/j.ymben.2020.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/20/2020] [Accepted: 05/01/2020] [Indexed: 12/19/2022]
Abstract
Methane, a non-expensive natural substrate, is used by Methylocystis spp. as a sole source of carbon and energy. Here, we assessed whether Methylocystis sp. strain SC2 is able to also utilize hydrogen as an energy source. The addition of 2% H2 to the culture headspace had the most significant positive effect on the growth yield under CH4 (6%) and O2 (3%) limited conditions. The SC2 biomass yield doubled from 6.41 (±0.52) to 13.82 (±0.69) mg cell dry weight per mmol CH4, while CH4 consumption was significantly reduced. Regardless of H2 addition, CH4 utilization was increasingly redirected from respiration to fermentation-based pathways with decreasing O2/CH4 mixing ratios. Theoretical thermodynamic calculations confirmed that hydrogen utilization under oxygen-limited conditions doubles the maximum biomass yield compared to fully aerobic conditions without H2 addition. Hydrogen utilization was linked to significant changes in the SC2 proteome. In addition to hydrogenase accessory proteins, the production of Group 1d and Group 2b hydrogenases was significantly increased in both short- and long-term incubations. Both long-term incubation with H2 (37 d) and treatments with chemical inhibitors revealed that SC2 growth under hydrogen-utilizing conditions does not require the activity of complex I. Apparently, strain SC2 has the metabolic capacity to channel hydrogen-derived electrons into the quinone pool, which provides a link between hydrogen oxidation and energy production. In summary, H2 may be a promising alternative energy source in biotechnologically oriented methanotroph projects that aim to maximize biomass yield from CH4, such as the production of high-quality feed protein.
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Affiliation(s)
- Anna Hakobyan
- Research Group "Methanotrophic Bacteria and Environmental Genomics/Transcriptomics", Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Jing Zhu
- Research Group "Methanotrophic Bacteria and Environmental Genomics/Transcriptomics", Max Planck Institute for Terrestrial Microbiology, Marburg, Germany; Institute of Environmental Science and Technology, Zhejiang University, Hangzhou, China
| | - Timo Glatter
- Core Facility for Mass Spectrometry and Proteomics, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Nicole Paczia
- Core Facility for Metabolomics and Small Molecule Mass Spectrometry, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Werner Liesack
- Research Group "Methanotrophic Bacteria and Environmental Genomics/Transcriptomics", Max Planck Institute for Terrestrial Microbiology, Marburg, Germany; Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany.
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30
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Leung PM, Bay SK, Meier DV, Chiri E, Cowan DA, Gillor O, Woebken D, Greening C. Energetic Basis of Microbial Growth and Persistence in Desert Ecosystems. mSystems 2020; 5:e00495-19. [PMID: 32291352 PMCID: PMC7159902 DOI: 10.1128/msystems.00495-19] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microbial life is surprisingly abundant and diverse in global desert ecosystems. In these environments, microorganisms endure a multitude of physicochemical stresses, including low water potential, carbon and nitrogen starvation, and extreme temperatures. In this review, we summarize our current understanding of the energetic mechanisms and trophic dynamics that underpin microbial function in desert ecosystems. Accumulating evidence suggests that dormancy is a common strategy that facilitates microbial survival in response to water and carbon limitation. Whereas photoautotrophs are restricted to specific niches in extreme deserts, metabolically versatile heterotrophs persist even in the hyper-arid topsoils of the Atacama Desert and Antarctica. At least three distinct strategies appear to allow such microorganisms to conserve energy in these oligotrophic environments: degradation of organic energy reserves, rhodopsin- and bacteriochlorophyll-dependent light harvesting, and oxidation of the atmospheric trace gases hydrogen and carbon monoxide. In turn, these principles are relevant for understanding the composition, functionality, and resilience of desert ecosystems, as well as predicting responses to the growing problem of desertification.
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Affiliation(s)
- Pok Man Leung
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Clayton, Victoria, Australia
| | - Sean K Bay
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Clayton, Victoria, Australia
| | - Dimitri V Meier
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Eleonora Chiri
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Clayton, Victoria, Australia
| | - Don A Cowan
- Centre for Microbial Ecology and Genomics, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Osnat Gillor
- Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sde Boker, Israel
| | - Dagmar Woebken
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Clayton, Victoria, Australia
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31
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de la Porte A, Schmidt R, Yergeau É, Constant P. A Gaseous Milieu: Extending the Boundaries of the Rhizosphere. Trends Microbiol 2020; 28:536-542. [PMID: 32544440 DOI: 10.1016/j.tim.2020.02.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/07/2019] [Accepted: 02/24/2020] [Indexed: 11/30/2022]
Abstract
Plant root activities shape microbial community functioning in the soil, making the rhizosphere the epicenter of soil biogeochemical processes. With this opinion article, we argue to rethink the rhizosphere boundaries: as gases can diffuse several centimeters away from the roots into the soil, the portion of soil influenced by root activities is larger than the strictly root-adhering soil. Indeed, gases are key drivers of biogeochemical processes due to their roles as energy sources or communication molecules, which has the potential to modify microbial community structure and functioning. In order to get a more holistic perspective on this key environment, we advocate for interdisciplinarity in rhizosphere research by combining knowledge of soluble compounds with gas dynamics.
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Affiliation(s)
- Anne de la Porte
- Institut National de la Recherche Scientifique, Centre Armand-Frappier Santé Biotechnologie, Laval, H7V 1B7, Canada; Quebec Center for Biodiversity Sciences (QCBS), Montreal, H3A 1B1, Canada
| | - Ruth Schmidt
- Institut National de la Recherche Scientifique, Centre Armand-Frappier Santé Biotechnologie, Laval, H7V 1B7, Canada; Quebec Center for Biodiversity Sciences (QCBS), Montreal, H3A 1B1, Canada.
| | - Étienne Yergeau
- Institut National de la Recherche Scientifique, Centre Armand-Frappier Santé Biotechnologie, Laval, H7V 1B7, Canada; Quebec Center for Biodiversity Sciences (QCBS), Montreal, H3A 1B1, Canada
| | - Philippe Constant
- Institut National de la Recherche Scientifique, Centre Armand-Frappier Santé Biotechnologie, Laval, H7V 1B7, Canada; Quebec Center for Biodiversity Sciences (QCBS), Montreal, H3A 1B1, Canada
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32
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It does not always take two to tango: "Syntrophy" via hydrogen cycling in one bacterial cell. ISME JOURNAL 2020; 14:1561-1570. [PMID: 32203116 PMCID: PMC7242416 DOI: 10.1038/s41396-020-0627-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 02/18/2020] [Accepted: 02/26/2020] [Indexed: 11/10/2022]
Abstract
Interspecies hydrogen transfer in anoxic ecosystems is essential for the complete microbial breakdown of organic matter to methane. Acetogenic bacteria are key players in anaerobic food webs and have been considered as prime candidates for hydrogen cycling. We have tested this hypothesis by mutational analysis of the hydrogenase in the model acetogen Acetobacterium woodii. Hydrogenase-deletion mutants no longer grew on H2 + CO2 or organic substrates such as fructose, lactate, or ethanol. Heterotrophic growth could be restored by addition of molecular hydrogen to the culture, indicating that hydrogen is an intermediate in heterotrophic growth. Indeed, hydrogen production from fructose was detected in a stirred-tank reactor. The mutant grew well on organic substrates plus caffeate, an alternative electron acceptor that does not require molecular hydrogen but NADH as reductant. These data are consistent with the notion that molecular hydrogen is produced from organic substrates and then used as reductant for CO2 reduction. Surprisingly, hydrogen cycling in A. woodii is different from the known modes of interspecies or intraspecies hydrogen cycling. Our data are consistent with a novel type of hydrogen cycling that connects an oxidative and reductive metabolic module in one bacterial cell, “intracellular syntrophy.”
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33
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Schmitz RA, Pol A, Mohammadi SS, Hogendoorn C, van Gelder AH, Jetten MSM, Daumann LJ, Op den Camp HJM. The thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV oxidizes subatmospheric H 2 with a high-affinity, membrane-associated [NiFe] hydrogenase. ISME JOURNAL 2020; 14:1223-1232. [PMID: 32042101 PMCID: PMC7174314 DOI: 10.1038/s41396-020-0609-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/28/2020] [Accepted: 01/30/2020] [Indexed: 12/23/2022]
Abstract
The trace amounts (0.53 ppmv) of atmospheric hydrogen gas (H2) can be utilized by microorganisms to persist during dormancy. This process is catalyzed by certain Actinobacteria, Acidobacteria, and Chloroflexi, and is estimated to convert 75 × 1012 g H2 annually, which is half of the total atmospheric H2. This rapid atmospheric H2 turnover is hypothesized to be catalyzed by high-affinity [NiFe] hydrogenases. However, apparent high-affinity H2 oxidation has only been shown in whole cells, rather than for the purified enzyme. Here, we show that the membrane-associated hydrogenase from the thermoacidophilic methanotroph Methylacidiphilum fumariolicum SolV possesses a high apparent affinity (Km(app) = 140 nM) for H2 and that methanotrophs can oxidize subatmospheric H2. Our findings add to the evidence that the group 1h [NiFe] hydrogenase is accountable for atmospheric H2 oxidation and that it therefore could be a strong controlling factor in the global H2 cycle. We show that the isolated enzyme possesses a lower affinity (Km = 300 nM) for H2 than the membrane-associated enzyme. Hence, the membrane association seems essential for a high affinity for H2. The enzyme is extremely thermostable and remains folded up to 95 °C. Strain SolV is the only known organism in which the group 1h [NiFe] hydrogenase is responsible for rapid growth on H2 as sole energy source as well as oxidation of subatmospheric H2. The ability to conserve energy from H2 could increase fitness of verrucomicrobial methanotrophs in geothermal ecosystems with varying CH4 fluxes. We propose that H2 oxidation can enhance growth of methanotrophs in aerated methane-driven ecosystems. Group 1h [NiFe] hydrogenases could therefore contribute to mitigation of global warming, since CH4 is an important and extremely potent greenhouse gas.
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Affiliation(s)
- Rob A Schmitz
- Department of Microbiology, Radboud University, Heyendaalseweg 135, NL-6525 AJ, Nijmegen, The Netherlands
| | - Arjan Pol
- Department of Microbiology, Radboud University, Heyendaalseweg 135, NL-6525 AJ, Nijmegen, The Netherlands
| | - Sepehr S Mohammadi
- Department of Microbiology, Radboud University, Heyendaalseweg 135, NL-6525 AJ, Nijmegen, The Netherlands
| | - Carmen Hogendoorn
- Department of Microbiology, Radboud University, Heyendaalseweg 135, NL-6525 AJ, Nijmegen, The Netherlands
| | - Antonie H van Gelder
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Radboud University, Heyendaalseweg 135, NL-6525 AJ, Nijmegen, The Netherlands
| | - Lena J Daumann
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraβe 5-13, D-81377, München, Germany
| | - Huub J M Op den Camp
- Department of Microbiology, Radboud University, Heyendaalseweg 135, NL-6525 AJ, Nijmegen, The Netherlands.
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34
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Aerobic nitrogen-fixing bacteria for hydrogen and ammonium production: current state and perspectives. Appl Microbiol Biotechnol 2019; 104:1383-1399. [PMID: 31879824 DOI: 10.1007/s00253-019-10210-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 10/16/2019] [Accepted: 10/20/2019] [Indexed: 10/25/2022]
Abstract
Biological nitrogen fixation (BNF) is accomplished through the action of the oxygen-sensitive enzyme nitrogenase. One unique caveat of this reaction is the inclusion of hydrogen gas (H2) evolution as a requirement of the reaction mechanism. In the absence of nitrogen gas as a substrate, nitrogenase will reduce available protons to become a directional ATP-dependent hydrogenase. Aerobic nitrogen-fixing microbes are of particular interest, because these organisms have evolved to perform these reactions with oxygen-sensitive enzymes in an environment surrounded by oxygen. The ability to maintain a functioning nitrogenase in aerobic conditions facilitates the application of these organisms under conditions where most anaerobic nitrogen fixers are excluded. In recent years, questions related to the potential yields of the nitrogenase-derived products ammonium and H2 have grown more approachable to experimentation based on efforts to construct increasingly more complicated strains of aerobic nitrogen fixers such as the obligate aerobe Azotobacter vinelandii. This mini-review provides perspectives of recent and historical efforts to understand and quantify the yields of ammonium and H2 that can be obtained through the model aerobe A. vinelandii, and outstanding questions that remain to be answered to fully realize the potential of nitrogenase in these applications with model aerobic bacteria.
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Islam ZF, Cordero PRF, Greening C. Putative Iron-Sulfur Proteins Are Required for Hydrogen Consumption and Enhance Survival of Mycobacteria. Front Microbiol 2019; 10:2749. [PMID: 31824474 PMCID: PMC6883350 DOI: 10.3389/fmicb.2019.02749] [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: 04/25/2019] [Accepted: 11/12/2019] [Indexed: 01/01/2023] Open
Abstract
Aerobic soil bacteria persist by scavenging molecular hydrogen (H2) from the atmosphere. This key process is the primary sink in the biogeochemical hydrogen cycle and supports the productivity of oligotrophic ecosystems. In Mycobacterium smegmatis, atmospheric H2 oxidation is catalyzed by two phylogenetically distinct [NiFe]-hydrogenases, Huc (group 2a) and Hhy (group 1h). However, it is currently unresolved how these enzymes transfer electrons derived from H2 oxidation into the aerobic respiratory chain. In this work, we used genetic approaches to confirm that two putative iron-sulfur cluster proteins encoded on the hydrogenase structural operons, HucE and HhyE, are required for H2 consumption in M. smegmatis. Sequence analysis show that these proteins, while homologous, fall into distinct phylogenetic clades and have distinct metal-binding motifs. H2 oxidation was reduced when the genes encoding these proteins were deleted individually and was eliminated when they were deleted in combination. In turn, the growth yield and long-term survival of these deletion strains was modestly but significantly reduced compared to the parent strain. In both biochemical and phenotypic assays, the mutant strains lacking the putative iron-sulfur proteins phenocopied those of hydrogenase structural subunit mutants. We hypothesize that these proteins mediate electron transfer between the catalytic subunits of the hydrogenases and the menaquinone pool of the M. smegmatis respiratory chain; however, other roles (e.g., in maturation) are also plausible and further work is required to resolve their role. The conserved nature of these proteins within most Hhy- or Huc-encoding organisms suggests that these proteins are important determinants of atmospheric H2 oxidation.
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Affiliation(s)
| | | | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
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Cordero PRF, Grinter R, Hards K, Cryle MJ, Warr CG, Cook GM, Greening C. Two uptake hydrogenases differentially interact with the aerobic respiratory chain during mycobacterial growth and persistence. J Biol Chem 2019; 294:18980-18991. [PMID: 31624148 DOI: 10.1074/jbc.ra119.011076] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/12/2019] [Indexed: 12/11/2022] Open
Abstract
To persist when nutrient sources are limited, aerobic soil bacteria metabolize atmospheric hydrogen (H2). This process is the primary sink in the global H2 cycle and supports the productivity of microbes in oligotrophic environments. H2-metabolizing bacteria possess [NiFe] hydrogenases that oxidize H2 to subatmospheric concentrations. The soil saprophyte Mycobacterium smegmatis has two such [NiFe] hydrogenases, designated Huc and Hhy, that belong to different phylogenetic subgroups. Both Huc and Hhy are oxygen-tolerant, oxidize H2 to subatmospheric concentrations, and enhance bacterial survival during hypoxia and carbon limitation. Why does M. smegmatis require two hydrogenases with a seemingly similar function? In this work, we resolved this question by showing that Huc and Hhy are differentially expressed, localized, and integrated into the respiratory chain. Huc is active in late exponential and early stationary phases, supporting energy conservation during mixotrophic growth and transition into dormancy. In contrast, Hhy is most active during long-term persistence, providing energy for maintenance processes following carbon exhaustion. We also show that Huc and Hhy are obligately linked to the aerobic respiratory chain via the menaquinone pool and are differentially affected by respiratory uncouplers. Consistently, these two enzymes interacted differentially with the respiratory terminal oxidases. Huc exclusively donated electrons to, and possibly physically associated with, the proton-pumping cytochrome bcc-aa 3 supercomplex. In contrast the more promiscuous Hhy also provided electrons to the cytochrome bd oxidase complex. These results indicate that, despite their similar characteristics, Huc and Hhy perform distinct functions during mycobacterial growth and survival.
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Affiliation(s)
- Paul R F Cordero
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Rhys Grinter
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Kiel Hards
- Department of Microbiology and Immunology, University of Otago, Dunedin, OTA 9016, New Zealand
| | - Max J Cryle
- Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Coral G Warr
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia.,School of Medicine, University of Tasmania, Hobart, TAS 7000, Australia
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, OTA 9016, New Zealand
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
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Alves RJE, Kerou M, Zappe A, Bittner R, Abby SS, Schmidt HA, Pfeifer K, Schleper C. Ammonia Oxidation by the Arctic Terrestrial Thaumarchaeote Candidatus Nitrosocosmicus arcticus Is Stimulated by Increasing Temperatures. Front Microbiol 2019; 10:1571. [PMID: 31379764 PMCID: PMC6657660 DOI: 10.3389/fmicb.2019.01571] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/24/2019] [Indexed: 11/13/2022] Open
Abstract
Climate change is causing arctic regions to warm disproportionally faster than those at lower latitudes, leading to alterations in carbon and nitrogen cycling, and potentially higher greenhouse gas emissions. It is thus increasingly important to better characterize the microorganisms driving arctic biogeochemical processes and their potential responses to changing conditions. Here, we describe a novel thaumarchaeon enriched from an arctic soil, Candidatus Nitrosocosmicus arcticus strain Kfb, which has been maintained for seven years in stable laboratory enrichment cultures as an aerobic ammonia oxidizer, with ammonium or urea as substrates. Genomic analyses show that this organism harbors all genes involved in ammonia oxidation and in carbon fixation via the 3-hydroxypropionate/4-hydroxybutyrate cycle, characteristic of all AOA, as well as the capability for urea utilization and potentially also for heterotrophic metabolism, similar to other AOA. Ca. N. arcticus oxidizes ammonia optimally between 20 and 28°C, well above average temperatures in its native high arctic environment (-13-4°C). Ammonia oxidation rates were nevertheless much lower than those of most cultivated mesophilic AOA (20-45°C). Intriguingly, we repeatedly observed apparent faster growth rates (based on marker gene counts) at lower temperatures (4-8°C) but without detectable nitrite production. Together with potential metabolisms predicted from its genome content, these observations indicate that Ca. N. arcticus is not a strict chemolithotrophic ammonia oxidizer and add to cumulating evidence for a greater metabolic and physiological versatility of AOA. The physiology of Ca. N. arcticus suggests that increasing temperatures might drastically affect nitrification in arctic soils by stimulating archaeal ammonia oxidation.
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Affiliation(s)
- Ricardo J Eloy Alves
- Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Melina Kerou
- Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Anna Zappe
- Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria.,Max F. Perutz Laboratories, Center for Integrative Bioinformatics Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria
| | - Romana Bittner
- Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Sophie S Abby
- Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| | - Heiko A Schmidt
- Max F. Perutz Laboratories, Center for Integrative Bioinformatics Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria
| | - Kevin Pfeifer
- Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria.,Institute for Synthetic Bioarchitectures, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Christa Schleper
- Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
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