1
|
Wang Y, Bai Y, Su J, Xu L, Ren Y, Ren M, Hou C, Cao M. Enhanced denitrification and p-nitrophenol removal performance via hydrophilic sponge carriers fixed with dual-bacterial: Optimization, performance, and enhancement mechanism. JOURNAL OF HAZARDOUS MATERIALS 2024; 475:134922. [PMID: 38885589 DOI: 10.1016/j.jhazmat.2024.134922] [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: 04/03/2024] [Revised: 05/18/2024] [Accepted: 06/13/2024] [Indexed: 06/20/2024]
Abstract
Effective treatment of industrial wastewater containing complex pollutants, such as nitrate (NO3--N) and organic pollutants, remains a significant challenge to date. Here, a strain Nocardioides sp. ZS2 with denitrification and degradation of p-nitrophenol (PNP) was isolated and its culture conditions were optimized by kinetic analysis. Hydrophilic sponge carriers were prepared using polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), and chitosan (CS) to construct bioreactors. Furthermore, to further enhance the PNP degradation and denitrification performance of bioreactors, Pseudomonas stutzeri GF2 with denitrification capability was introduced. The results revealed that the removal efficiencies of PNP and NO3--N reached 97.9 % and 91.9 %, respectively, when hydraulic retention time (HRT) of 6 h, C/N of 2.0, and pH of 6.5. The bioreactor exhibited stable denitrification performance even with fluctuations in the influent PNP concentration. The potential functional prediction results revealed that the abundance of amino acids, fatty acids, and carbohydrates increased as the influent C/N decreased, reflecting a tendency of the microbial community to adjust carbon source utilization to maintain cell growth, metabolic balance, and resist adverse C/N environments. This research provides new insights into the effective removal of organic pollutants and NO3--N in wastewater treatment.
Collapse
Affiliation(s)
- Yue Wang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yihan Bai
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Junfeng Su
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Liang Xu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yi Ren
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Miqi Ren
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Chenxi Hou
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Meng Cao
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| |
Collapse
|
2
|
Kang L, Song Y, Mackelprang R, Zhang D, Qin S, Chen L, Wu L, Peng Y, Yang Y. Metagenomic insights into microbial community structure and metabolism in alpine permafrost on the Tibetan Plateau. Nat Commun 2024; 15:5920. [PMID: 39004662 PMCID: PMC11247091 DOI: 10.1038/s41467-024-50276-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 07/05/2024] [Indexed: 07/16/2024] Open
Abstract
Permafrost, characterized by its frozen soil, serves as a unique habitat for diverse microorganisms. Understanding these microbial communities is crucial for predicting the response of permafrost ecosystems to climate change. However, large-scale evidence regarding stratigraphic variations in microbial profiles remains limited. Here, we analyze microbial community structure and functional potential based on 16S rRNA gene amplicon sequencing and metagenomic data obtained from an ∼1000 km permafrost transect on the Tibetan Plateau. We find that microbial alpha diversity declines but beta diversity increases down the soil profile. Microbial assemblages are primarily governed by dispersal limitation and drift, with the importance of drift decreasing but that of dispersal limitation increasing with soil depth. Moreover, genes related to reduction reactions (e.g., ferric iron reduction, dissimilatory nitrate reduction, and denitrification) are enriched in the subsurface and permafrost layers. In addition, microbial groups involved in alternative electron accepting processes are more diverse and contribute highly to community-level metabolic profiles in the subsurface and permafrost layers, likely reflecting the lower redox potential and more complicated trophic strategies for microorganisms in deeper soils. Overall, these findings provide comprehensive insights into large-scale stratigraphic profiles of microbial community structure and functional potentials in permafrost regions.
Collapse
Affiliation(s)
- Luyao Kang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yutong Song
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | | | - Dianye Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
| | - Shuqi Qin
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
| | - Leiyi Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
| | - Linwei Wu
- Institute of Ecology, Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Yunfeng Peng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
- China National Botanical Garden, Beijing, China.
- University of Chinese Academy of Sciences, Beijing, China.
| |
Collapse
|
3
|
Li L, Huang H, Jin Z, Jiang K, Zeng Y, Pathier D, Cheng X, Shen W. Strawberry Yield Improvement by Hydrogen-Based Irrigation Is Functionally Linked to Altered Rhizosphere Microbial Communities. PLANTS (BASEL, SWITZERLAND) 2024; 13:1723. [PMID: 38999563 PMCID: PMC11243525 DOI: 10.3390/plants13131723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 06/10/2024] [Accepted: 06/17/2024] [Indexed: 07/14/2024]
Abstract
Molecular hydrogen (H2) is crucial for agricultural microbial systems. However, the mechanisms underlying its influence on crop yields is yet to be fully elucidated. This study observed that H2-based irrigation significantly increased strawberry (Fragaria × ananassa Duch.) yield with/without nutrient fertilization. The reduction in soil available nitrogen (N), phosphorus (P), potassium (K), and organic matter was consistent with the increased expression levels of N/P/K-absorption-related genes in root tissues at the fruiting stage. Metagenomics profiling showed the alterations in rhizosphere microbial community composition achieved by H2, particularly under the conditions without fertilizers. These included the enrichment of plant-growth-promoting rhizobacteria, such as Burkholderia, Pseudomonas, and Cupriavidus genera. Rhizobacteria with the capability to oxidize H2 (group 2a [NiFe] hydrogenase) were also enriched. Consistently, genes related to soil carbon (C) fixation (i.e., rbcL, porD, frdAB, etc.), dissimilar nitrate reduction (i.e., napAB and nrfAH), and P solublization, mineralization, and transportation (i.e., ppx-gppA, appA, and ugpABCE) exhibited higher abundance. Contrary tendencies were observed in the soil C degradation and N denitrification genes. Together, these results clearly indicate that microbe-mediated soil C, N, and P cycles might be functionally altered by H2, thus increasing plant nutrient uptake capacity and horticultural crop yield.
Collapse
Affiliation(s)
- Longna Li
- Laboratory Center of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (L.L.); (H.H.); (Z.J.); (K.J.)
| | - Huize Huang
- Laboratory Center of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (L.L.); (H.H.); (Z.J.); (K.J.)
| | - Zhiwei Jin
- Laboratory Center of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (L.L.); (H.H.); (Z.J.); (K.J.)
| | - Ke Jiang
- Laboratory Center of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (L.L.); (H.H.); (Z.J.); (K.J.)
| | - Yan Zeng
- Air Liquide (China) R&D Co., Ltd., Shanghai 201108, China; (Y.Z.); (D.P.); (X.C.)
| | - Didier Pathier
- Air Liquide (China) R&D Co., Ltd., Shanghai 201108, China; (Y.Z.); (D.P.); (X.C.)
| | - Xu Cheng
- Air Liquide (China) R&D Co., Ltd., Shanghai 201108, China; (Y.Z.); (D.P.); (X.C.)
| | - Wenbiao Shen
- Laboratory Center of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (L.L.); (H.H.); (Z.J.); (K.J.)
| |
Collapse
|
4
|
Qi YL, Chen YT, Xie YG, Li YX, Rao YZ, Li MM, Xie QJ, Cao XR, Chen L, Qu YN, Yuan ZX, Xiao ZC, Lu L, Jiao JY, Shu WS, Li WJ, Hedlund BP, Hua ZS. Analysis of nearly 3000 archaeal genomes from terrestrial geothermal springs sheds light on interconnected biogeochemical processes. Nat Commun 2024; 15:4066. [PMID: 38744885 PMCID: PMC11094006 DOI: 10.1038/s41467-024-48498-5] [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: 09/07/2023] [Accepted: 05/02/2024] [Indexed: 05/16/2024] Open
Abstract
Terrestrial geothermal springs are physicochemically diverse and host abundant populations of Archaea. However, the diversity, functionality, and geological influences of these Archaea are not well understood. Here we explore the genomic diversity of Archaea in 152 metagenomes from 48 geothermal springs in Tengchong, China, collected from 2016 to 2021. Our dataset is comprised of 2949 archaeal metagenome-assembled genomes spanning 12 phyla and 392 newly identified species, which increases the known species diversity of Archaea by ~48.6%. The structures and potential functions of the archaeal communities are strongly influenced by temperature and pH, with high-temperature acidic and alkaline springs favoring archaeal abundance over Bacteria. Genome-resolved metagenomics and metatranscriptomics provide insights into the potential ecological niches of these Archaea and their potential roles in carbon, sulfur, nitrogen, and hydrogen metabolism. Furthermore, our findings illustrate the interplay of competition and cooperation among Archaea in biogeochemical cycles, possibly arising from overlapping functional niches and metabolic handoffs. Taken together, our study expands the genomic diversity of Archaea inhabiting geothermal springs and provides a foundation for more incisive study of biogeochemical processes mediated by Archaea in geothermal ecosystems.
Collapse
Affiliation(s)
- Yan-Ling Qi
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Ya-Ting Chen
- Institute for Disaster Management and Reconstruction, Sichuan University-Hong Kong Polytechnic University, Chengdu, 610207, China
| | - Yuan-Guo Xie
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Yu-Xian Li
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Yang-Zhi Rao
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Meng-Meng Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China
| | - Qi-Jun Xie
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Xing-Ru Cao
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Lei Chen
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Yan-Ni Qu
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Zhen-Xuan Yuan
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Zhi-Chao Xiao
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China
| | - Lu Lu
- College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China
| | - Jian-Yu Jiao
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China
| | - Wen-Sheng Shu
- School of Life Sciences, South China Normal University, Guangzhou, PR China
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, PR China.
| | - Brian P Hedlund
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, 89154, USA.
- Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV, 89154, USA.
| | - Zheng-Shuang Hua
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China.
| |
Collapse
|
5
|
Leung PM, Grinter R, Tudor-Matthew E, Lingford JP, Jimenez L, Lee HC, Milton M, Hanchapola I, Tanuwidjaya E, Kropp A, Peach HA, Carere CR, Stott MB, Schittenhelm RB, Greening C. Trace gas oxidation sustains energy needs of a thermophilic archaeon at suboptimal temperatures. Nat Commun 2024; 15:3219. [PMID: 38622143 PMCID: PMC11018855 DOI: 10.1038/s41467-024-47324-2] [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: 02/03/2023] [Accepted: 03/22/2024] [Indexed: 04/17/2024] Open
Abstract
Diverse aerobic bacteria use atmospheric hydrogen (H2) and carbon monoxide (CO) as energy sources to support growth and survival. Such trace gas oxidation is recognised as a globally significant process that serves as the main sink in the biogeochemical H2 cycle and sustains microbial biodiversity in oligotrophic ecosystems. However, it is unclear whether archaea can also use atmospheric H2. Here we show that a thermoacidophilic archaeon, Acidianus brierleyi (Thermoproteota), constitutively consumes H2 and CO to sub-atmospheric levels. Oxidation occurs across a wide range of temperatures (10 to 70 °C) and enhances ATP production during starvation-induced persistence under temperate conditions. The genome of A. brierleyi encodes a canonical CO dehydrogenase and four distinct [NiFe]-hydrogenases, which are differentially produced in response to electron donor and acceptor availability. Another archaeon, Metallosphaera sedula, can also oxidize atmospheric H2. Our results suggest that trace gas oxidation is a common trait of Sulfolobales archaea and may play a role in their survival and niche expansion, including during dispersal through temperate environments.
Collapse
Affiliation(s)
- Pok Man Leung
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
| | - Rhys Grinter
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Eve Tudor-Matthew
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - James P Lingford
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Luis Jimenez
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Han-Chung Lee
- Monash Proteomics and Metabolomics Platform and Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Michael Milton
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Iresha Hanchapola
- Monash Proteomics and Metabolomics Platform and Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Erwin Tanuwidjaya
- Monash Proteomics and Metabolomics Platform and Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Ashleigh Kropp
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Hanna A Peach
- Geomicrobiology Research Group, Department of Geothermal Sciences, Te Pū Ao | GNS Science, Wairakei, Taupō, 3377, Aotearoa New Zealand
| | - Carlo R Carere
- Geomicrobiology Research Group, Department of Geothermal Sciences, Te Pū Ao | GNS Science, Wairakei, Taupō, 3377, Aotearoa New Zealand
- Te Tari Pūhanga Tukanga Matū | Department of Chemical and Process Engineering, Te Whare Wānanga o Waitaha | University of Canterbury, Christchurch, 8140, Aotearoa New Zealand
| | - Matthew B Stott
- Geomicrobiology Research Group, Department of Geothermal Sciences, Te Pū Ao | GNS Science, Wairakei, Taupō, 3377, Aotearoa New Zealand
- Te Kura Pūtaiao Koiora | School of Biological Sciences, Te Whare Wānanga o Waitaha | University of Canterbury, Christchurch, 8140, Aotearoa New Zealand
| | - Ralf B Schittenhelm
- Monash Proteomics and Metabolomics Platform and Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
| |
Collapse
|
6
|
Williams TJ, Allen MA, Ray AE, Benaud N, Chelliah DS, Albanese D, Donati C, Selbmann L, Coleine C, Ferrari BC. Novel endolithic bacteria of phylum Chloroflexota reveal a myriad of potential survival strategies in the Antarctic desert. Appl Environ Microbiol 2024; 90:e0226423. [PMID: 38372512 PMCID: PMC10952385 DOI: 10.1128/aem.02264-23] [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] [Received: 12/15/2023] [Accepted: 01/02/2024] [Indexed: 02/20/2024] Open
Abstract
The ice-free McMurdo Dry Valleys of Antarctica are dominated by nutrient-poor mineral soil and rocky outcrops. The principal habitat for microorganisms is within rocks (endolithic). In this environment, microorganisms are provided with protection against sub-zero temperatures, rapid thermal fluctuations, extreme dryness, and ultraviolet and solar radiation. Endolithic communities include lichen, algae, fungi, and a diverse array of bacteria. Chloroflexota is among the most abundant bacterial phyla present in these communities. Among the Chloroflexota are four novel classes of bacteria, here named Candidatus Spiritibacteria class. nov. (=UBA5177), Candidatus Martimicrobia class. nov. (=UBA4733), Candidatus Tarhunnaeia class. nov. (=UBA6077), and Candidatus Uliximicrobia class. nov. (=UBA2235). We retrieved 17 high-quality metagenome-assembled genomes (MAGs) that represent these four classes. Based on genome predictions, all these bacteria are inferred to be aerobic heterotrophs that encode enzymes for the catabolism of diverse sugars. These and other organic substrates are likely derived from lichen, algae, and fungi, as metabolites (including photosynthate), cell wall components, and extracellular matrix components. The majority of MAGs encode the capacity for trace gas oxidation using high-affinity uptake hydrogenases, which could provide energy and metabolic water required for survival and persistence. Furthermore, some MAGs encode the capacity to couple the energy generated from H2 and CO oxidation to support carbon fixation (atmospheric chemosynthesis). All encode mechanisms for the detoxification and efflux of heavy metals. Certain MAGs encode features that indicate possible interactions with other organisms, such as Tc-type toxin complexes, hemolysins, and macroglobulins.IMPORTANCEThe ice-free McMurdo Dry Valleys of Antarctica are the coldest and most hyperarid desert on Earth. It is, therefore, the closest analog to the surface of the planet Mars. Bacteria and other microorganisms survive by inhabiting airspaces within rocks (endolithic). We identify four novel classes of phylum Chloroflexota, and, based on interrogation of 17 metagenome-assembled genomes, we predict specific metabolic and physiological adaptations that facilitate the survival of these bacteria in this harsh environment-including oxidation of trace gases and the utilization of nutrients (including sugars) derived from lichen, algae, and fungi. We propose that such adaptations allow these endolithic bacteria to eke out an existence in this cold and extremely dry habitat.
Collapse
Affiliation(s)
- Timothy J. Williams
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Michelle A. Allen
- School of Biological, Earth and Environmental Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Angelique E. Ray
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Nicole Benaud
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Devan S. Chelliah
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Davide Albanese
- Research and Innovation Center, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Claudio Donati
- Research and Innovation Center, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Laura Selbmann
- Department of Ecological and Biological Sciences, University of Tuscia, Largo dell’Università, Viterbo, Italy
- Mycological Section, Italian Antarctic National Museum (MNA), Genova, Italy
| | - Claudia Coleine
- Department of Ecological and Biological Sciences, University of Tuscia, Largo dell’Università, Viterbo, Italy
| | - Belinda C. Ferrari
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| |
Collapse
|
7
|
Garvin ZK, Abades SR, Trefault N, Alfaro FD, Sipes K, Lloyd KG, Onstott TC. Prevalence of trace gas-oxidizing soil bacteria increases with radial distance from Polloquere hot spring within a high-elevation Andean cold desert. THE ISME JOURNAL 2024; 18:wrae062. [PMID: 38625060 PMCID: PMC11094475 DOI: 10.1093/ismejo/wrae062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/29/2024] [Accepted: 04/10/2024] [Indexed: 04/17/2024]
Abstract
High-elevation arid regions harbor microbial communities reliant on metabolic niches and flexibility to survive under biologically stressful conditions, including nutrient limitation that necessitates the utilization of atmospheric trace gases as electron donors. Geothermal springs present "oases" of microbial activity, diversity, and abundance by delivering water and substrates, including reduced gases. However, it is unknown whether these springs exhibit a gradient of effects, increasing their impact on trace gas-oxidizers in the surrounding soils. We assessed whether proximity to Polloquere, a high-altitude geothermal spring in an Andean salt flat, alters the diversity and metabolic structure of nearby soil bacterial populations compared to the surrounding cold desert. Recovered DNA and metagenomic analyses indicate that the spring represents an oasis for microbes in this challenging environment, supporting greater biomass with more diverse metabolic functions in proximal soils that declines sharply with radial distance from the spring. Despite the sharp decrease in biomass, potential rates of atmospheric hydrogen (H2) and carbon monoxide (CO) uptake increase away from the spring. Kinetic estimates suggest this activity is due to high-affinity trace gas consumption, likely as a survival strategy for energy/carbon acquisition. These results demonstrate that Polloquere regulates a gradient of diverse microbial communities and metabolisms, culminating in increased activity of trace gas-oxidizers as the influence of the spring yields to that of the regional salt flat environment. This suggests the spring holds local importance within the context of the broader salt flat and potentially represents a model ecosystem for other geothermal systems in high-altitude desert environments.
Collapse
Affiliation(s)
- Zachary K Garvin
- Department of Geosciences, Princeton University, Princeton, NJ 08544, United States
| | - Sebastián R Abades
- GEMA Center for Genomics, Ecology and Environment, Faculty of Interdisciplinary Studies, Universidad Mayor, 8580745, Santiago, Chile
| | - Nicole Trefault
- GEMA Center for Genomics, Ecology and Environment, Faculty of Interdisciplinary Studies, Universidad Mayor, 8580745, Santiago, Chile
| | - Fernando D Alfaro
- GEMA Center for Genomics, Ecology and Environment, Faculty of Interdisciplinary Studies, Universidad Mayor, 8580745, Santiago, Chile
| | - Katie Sipes
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, United States
- Department of Environmental Science, Aarhus University, 4000, Roskilde, Denmark
| | - Karen G Lloyd
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tullis C Onstott
- Department of Geosciences, Princeton University, Princeton, NJ 08544, United States
| |
Collapse
|
8
|
Ray AE, Tribbia DZ, Cowan DA, Ferrari BC. Clearing the air: unraveling past and guiding future research in atmospheric chemosynthesis. Microbiol Mol Biol Rev 2023; 87:e0004823. [PMID: 37914532 PMCID: PMC10732025 DOI: 10.1128/mmbr.00048-23] [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: 11/03/2023] Open
Abstract
SUMMARY Atmospheric chemosynthesis is a recently proposed form of chemoautotrophic microbial primary production. The proposed process relies on the oxidation of trace concentrations of hydrogen (≤530 ppbv), carbon monoxide (≤90 ppbv), and methane (≤1,870 ppbv) gases using high-affinity enzymes. Atmospheric hydrogen and carbon monoxide oxidation have been primarily linked to microbial growth in desert surface soils scarce in liquid water and organic nutrients, and low in photosynthetic communities. It is well established that the oxidation of trace hydrogen and carbon monoxide gases widely supports the persistence of microbial communities in a diminished metabolic state, with the former potentially providing a reliable source of metabolic water. Microbial atmospheric methane oxidation also occurs in oligotrophic desert soils and is widespread throughout copiotrophic environments, with established links to microbial growth. Despite these findings, the direct link between trace gas oxidation and carbon fixation remains disputable. Here, we review the supporting evidence, outlining major gaps in our understanding of this phenomenon, and propose approaches to validate atmospheric chemosynthesis as a primary production process. We also explore the implications of this minimalistic survival strategy in terms of nutrient cycling, climate change, aerobiology, and astrobiology.
Collapse
Affiliation(s)
- Angelique E. Ray
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, Australia
- Australian Centre for Astrobiology, UNSW Sydney, Sydney, Australia
| | - Dana Z. Tribbia
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, Australia
- Australian Centre for Astrobiology, UNSW Sydney, Sydney, Australia
| | - Don A. Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Belinda C. Ferrari
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, Australia
- Australian Centre for Astrobiology, UNSW Sydney, Sydney, Australia
| |
Collapse
|
9
|
Greening C, Kropp A, Vincent K, Grinter R. Developing high-affinity, oxygen-insensitive [NiFe]-hydrogenases as biocatalysts for energy conversion. Biochem Soc Trans 2023; 51:1921-1933. [PMID: 37743798 PMCID: PMC10657181 DOI: 10.1042/bst20230120] [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: 08/14/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 09/26/2023]
Abstract
The splitting of hydrogen (H2) is an energy-yielding process, which is important for both biological systems and as a means of providing green energy. In biology, this reaction is mediated by enzymes called hydrogenases, which utilise complex nickel and iron cofactors to split H2 and transfer the resulting electrons to an electron-acceptor. These [NiFe]-hydrogenases have received considerable attention as catalysts in fuel cells, which utilise H2 to produce electrical current. [NiFe]-hydrogenases are a promising alternative to the platinum-based catalysts that currently predominate in fuel cells due to the abundance of nickel and iron, and the resistance of some family members to inhibition by gases, including carbon monoxide, which rapidly poison platinum-based catalysts. However, the majority of characterised [NiFe]-hydrogenases are inhibited by oxygen (O2), limiting their activity and stability. We recently reported the isolation and characterisation of the [NiFe]-hydrogenase Huc from Mycobacterium smegmatis, which is insensitive to inhibition by O2 and has an extremely high affinity, making it capable of oxidising H2 in air to below atmospheric concentrations. These properties make Huc a promising candidate for the development of enzyme-based fuel cells (EBFCs), which utilise H2 at low concentrations and in impure gas mixtures. In this review, we aim to provide context for the use of Huc for this purpose by discussing the advantages of [NiFe]-hydrogenases as catalysts and their deployment in fuel cells. We also address the challenges associated with using [NiFe]-hydrogenases for this purpose, and how these might be overcome to develop EBFCs that can be deployed at scale.
Collapse
Affiliation(s)
- Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
- Securing Antarctica's Environmental Future, Monash University, Clayton, VIC 3800, Australia
- Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia
- ARC Research Hub for Carbon Utilisation and Recycling, Monash University, Clayton, VIC 3800, Australia
| | - Ashleigh Kropp
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Kylie Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford OX1 3QR, U.K
| | - Rhys Grinter
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
- Centre for Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria 3052, Australia
| |
Collapse
|
10
|
Aldeguer-Riquelme B, Antón J, Santos F. Distribution, abundance, and ecogenomics of the Palauibacterales, a new cosmopolitan thiamine-producing order within the Gemmatimonadota phylum. mSystems 2023; 8:e0021523. [PMID: 37345931 PMCID: PMC10469786 DOI: 10.1128/msystems.00215-23] [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] [Received: 03/05/2023] [Accepted: 04/19/2023] [Indexed: 06/23/2023] Open
Abstract
The phylum Gemmatimonadota comprises mainly uncultured microorganisms that inhabit different environments such as soils, freshwater lakes, marine sediments, sponges, or corals. Based on 16S rRNA gene studies, the group PAUC43f is one of the most frequently retrieved Gemmatimonadota in marine samples. However, its physiology and ecological roles are completely unknown since, to date, not a single PAUC43f isolate or metagenome-assembled genome (MAG) has been characterized. Here, we carried out a broad study of the distribution, abundance, ecotaxonomy, and metabolism of PAUC43f, for which we propose the name of Palauibacterales. This group was detected in 4,965 16S rRNA gene amplicon datasets, mainly from marine sediments, sponges, corals, soils, and lakes, reaching up to 34.3% relative abundance, which highlights its cosmopolitan character, mainly salt-related. The potential metabolic capabilities inferred from 52 Palauibacterales MAGs recovered from marine sediments, sponges, and saline soils suggested a facultative aerobic and chemoorganotrophic metabolism, although some members may also oxidize hydrogen. Some Palauibacterales species might also play an environmental role as N2O consumers as well as suppliers of serine and thiamine. When compared to the rest of the Gemmatimonadota phylum, the biosynthesis of thiamine was one of the key features of the Palauibacterales. Finally, we show that polysaccharide utilization loci (PUL) are widely distributed within the Gemmatimonadota so that they are not restricted to Bacteroidetes, as previously thought. Our results expand the knowledge about this cryptic phylum and provide new insights into the ecological roles of the Gemmatimonadota in the environment. IMPORTANCE Despite advances in molecular and sequencing techniques, there is still a plethora of unknown microorganisms with a relevant ecological role. In the last years, the mostly uncultured Gemmatimonadota phylum is attracting scientific interest because of its widespread distribution and abundance, but very little is known about its ecological role in the marine ecosystem. Here we analyze the global distribution and potential metabolism of the marine Gemmatimonadota group PAUC43f, for which we propose the name of Palauibacterales order. This group presents a saline-related character and a chemoorganoheterotrophic and facultatively aerobic metabolism, although some species might oxidize H2. Given that Palauibacterales is potentially able to synthesize thiamine, whose auxotrophy is the second most common in the marine environment, we propose Palauibacterales as a key thiamine supplier to the marine communities. This finding suggests that Gemmatimonadota could have a more relevant role in the marine environment than previously thought.
Collapse
Affiliation(s)
- Borja Aldeguer-Riquelme
- Department of Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain
| | - Josefa Antón
- Department of Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain
- Multidisciplinary Institute of Environmental Studies Ramón Margalef, University of Alicante, Alicante, Spain
| | - Fernando Santos
- Department of Physiology, Genetics, and Microbiology, University of Alicante, Alicante, Spain
| |
Collapse
|
11
|
Islam ZF, Greening C, Hu HW. Microbial hydrogen cycling in agricultural systems - plant beneficial or detrimental? Microb Biotechnol 2023. [PMID: 37354042 PMCID: PMC10364306 DOI: 10.1111/1751-7915.14300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 06/11/2023] [Indexed: 06/26/2023] Open
Abstract
Hydrogen-oxidising bacteria play a key role in maintaining the composition of gases within the atmosphere and are ubiquitous in agricultural soils. While studies have shown that hydrogen accumulates in soil surrounding legume nodules and the soil surface, soils as a whole act as a net sink for hydrogen, raising questions about how hydrogen is internally recycled by soils. Can the energy derived from hydrogen oxidation be directly funnelled into plants to promote their growth or does it only act as a booster for other plant-growth promoting bacteria? Moreover, while the fertilisation effect of hydrogen on plants has previously been shown to be beneficial, questions remain about the upper limit of hydrogen uptake by plants before it becomes detrimental. Agricultural practices such as fertilisation may impact the balance of hydrogen-oxidisers and hydrogen-producers in these ecosystems, potentially having detrimental effects on not only agricultural land but also global biogeochemical cycles. In this perspectives piece, we highlight the importance of understanding the contribution of hydrogen to agricultural soils and the effects of agricultural practices on the ability for bacteria to cycle hydrogen in agricultural soils. We propose a framework to gain better insights into microbial hydrogen cycling within agroecosystems, which could contribute to the development of new agricultural biotechnologies.
Collapse
Affiliation(s)
- Zahra F Islam
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, Parkville, Victoria, Australia
- ARC Research Hub for Smart Fertilisers, The University of Melbourne, Parkville, Victoria, Australia
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
- SAEF: Securing Antarctica's Environmental Future, Monash University, Clayton, Victoria, Australia
| | - Hang-Wei Hu
- School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, The University of Melbourne, Parkville, Victoria, Australia
- ARC Research Hub for Smart Fertilisers, The University of Melbourne, Parkville, Victoria, Australia
| |
Collapse
|
12
|
Grinter R, Kropp A, Venugopal H, Senger M, Badley J, Cabotaje PR, Jia R, Duan Z, Huang P, Stripp ST, Barlow CK, Belousoff M, Shafaat HS, Cook GM, Schittenhelm RB, Vincent KA, Khalid S, Berggren G, Greening C. Structural basis for bacterial energy extraction from atmospheric hydrogen. Nature 2023; 615:541-547. [PMID: 36890228 PMCID: PMC10017518 DOI: 10.1038/s41586-023-05781-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 02/02/2023] [Indexed: 03/10/2023]
Abstract
Diverse aerobic bacteria use atmospheric H2 as an energy source for growth and survival1. This globally significant process regulates the composition of the atmosphere, enhances soil biodiversity and drives primary production in extreme environments2,3. Atmospheric H2 oxidation is attributed to uncharacterized members of the [NiFe] hydrogenase superfamily4,5. However, it remains unresolved how these enzymes overcome the extraordinary catalytic challenge of oxidizing picomolar levels of H2 amid ambient levels of the catalytic poison O2 and how the derived electrons are transferred to the respiratory chain1. Here we determined the cryo-electron microscopy structure of the Mycobacterium smegmatis hydrogenase Huc and investigated its mechanism. Huc is a highly efficient oxygen-insensitive enzyme that couples oxidation of atmospheric H2 to the hydrogenation of the respiratory electron carrier menaquinone. Huc uses narrow hydrophobic gas channels to selectively bind atmospheric H2 at the expense of O2, and 3 [3Fe-4S] clusters modulate the properties of the enzyme so that atmospheric H2 oxidation is energetically feasible. The Huc catalytic subunits form an octameric 833 kDa complex around a membrane-associated stalk, which transports and reduces menaquinone 94 Å from the membrane. These findings provide a mechanistic basis for the biogeochemically and ecologically important process of atmospheric H2 oxidation, uncover a mode of energy coupling dependent on long-range quinone transport, and pave the way for the development of catalysts that oxidize H2 in ambient air.
Collapse
Affiliation(s)
- Rhys Grinter
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
| | - Ashleigh Kropp
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Hari Venugopal
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Victoria, Australia
| | - Moritz Senger
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Jack Badley
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Princess R Cabotaje
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Ruyu Jia
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Zehui Duan
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, UK
| | - Ping Huang
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Sven T Stripp
- Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, Berlin, Germany
| | - Christopher K Barlow
- Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Monash Proteomics and Metabolomics Facility, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Matthew Belousoff
- Centre for Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Hannah S Shafaat
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Ralf B Schittenhelm
- Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Monash Proteomics and Metabolomics Facility, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Kylie A Vincent
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, UK
| | - Syma Khalid
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Gustav Berggren
- Department of Chemistry, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
- Securing Antarctica's Environmental Future, Monash University, Clayton, Victoria, Australia.
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia.
- ARC Research Hub for Carbon Utilisation and Recycling, Monash University, Clayton, Victoria, Australia.
| |
Collapse
|
13
|
Molecular hydrogen in seawater supports growth of diverse marine bacteria. Nat Microbiol 2023; 8:581-595. [PMID: 36747116 DOI: 10.1038/s41564-023-01322-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 01/05/2023] [Indexed: 02/08/2023]
Abstract
Molecular hydrogen (H2) is an abundant and readily accessible energy source in marine systems, but it remains unknown whether marine microbial communities consume this gas. Here we use a suite of approaches to show that marine bacteria consume H2 to support growth. Genes for H2-uptake hydrogenases are prevalent in global ocean metagenomes, highly expressed in metatranscriptomes and found across eight bacterial phyla. Capacity for H2 oxidation increases with depth and decreases with oxygen concentration, suggesting that H2 is important in environments with low primary production. Biogeochemical measurements of tropical, temperate and subantarctic waters, and axenic cultures show that marine microbes consume H2 supplied at environmentally relevant concentrations, yielding enough cell-specific power to support growth in bacteria with low energy requirements. Conversely, our results indicate that oxidation of carbon monoxide (CO) primarily supports survival. Altogether, H2 is a notable energy source for marine bacteria and may influence oceanic ecology and biogeochemistry.
Collapse
|
14
|
Ni G, Lappan R, Hernández M, Santini T, Tomkins AG, Greening C. Functional basis of primary succession: Traits of the pioneer microbes. Environ Microbiol 2023; 25:171-176. [PMID: 36309943 PMCID: PMC10098604 DOI: 10.1111/1462-2920.16266] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 10/27/2022] [Indexed: 01/21/2023]
Affiliation(s)
- Gaofeng Ni
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Rachael Lappan
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Marcela Hernández
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom
| | - Talitha Santini
- School of Agriculture and Environment, University of Western Australia, Perth, Western Australia, Australia
| | - Andrew G Tomkins
- School of Earth, Atmosphere & Environment, Monash University, Clayton, Victoria, Australia
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.,Securing Antarctica's Environmental Future, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
15
|
Mandal S, Bose H, Ramesh K, Sahu RP, Saha A, Sar P, Kazy SK. Depth wide distribution and metabolic potential of chemolithoautotrophic microorganisms reactivated from deep continental granitic crust underneath the Deccan Traps at Koyna, India. Front Microbiol 2022; 13:1018940. [PMID: 36504802 PMCID: PMC9731672 DOI: 10.3389/fmicb.2022.1018940] [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: 08/14/2022] [Accepted: 11/01/2022] [Indexed: 11/25/2022] Open
Abstract
Characterization of inorganic carbon (C) utilizing microorganisms from deep crystalline rocks is of major scientific interest owing to their crucial role in global carbon and other elemental cycles. In this study we investigate the microbial populations from the deep [up to 2,908 meters below surface (mbs)] granitic rocks within the Koyna seismogenic zone, reactivated (enriched) under anaerobic, high temperature (50°C), chemolithoautotrophic conditions. Subsurface rock samples from six different depths (1,679-2,908 mbs) are incubated (180 days) with CO2 (+H2) or HCO3 - as the sole C source. Estimation of total protein, ATP, utilization of NO3 - and SO4 2- and 16S rRNA gene qPCR suggests considerable microbial growth within the chemolithotrophic conditions. We note a better response of rock hosted community towards CO2 (+H2) over HCO3 -. 16S rRNA gene amplicon sequencing shows a depth-wide distribution of diverse chemolithotrophic (and a few fermentative) Bacteria and Archaea. Comamonas, Burkholderia-Caballeronia-Paraburkholderia, Ralstonia, Klebsiella, unclassified Burkholderiaceae and Enterobacteriaceae are reactivated as dominant organisms from the enrichments of the deeper rocks (2335-2,908 mbs) with both CO2 and HCO3 -. For the rock samples from shallower depths, organisms of varied taxa are enriched under CO2 (+H2) and HCO3 -. Pseudomonas, Rhodanobacter, Methyloversatilis, and Thaumarchaeota are major CO2 (+H2) utilizers, while Nocardioides, Sphingomonas, Aeromonas, respond towards HCO3 -. H2 oxidizing Cupriavidus, Hydrogenophilus, Hydrogenophaga, CO2 fixing Cyanobacteria Rhodobacter, Clostridium, Desulfovibrio and methanogenic archaea are also enriched. Enriched chemolithoautotrophic members show good correlation with CO2, CH4 and H2 concentrations of the native rock environments, while the organisms from upper horizons correlate more to NO3 -, SO4 2- , Fe and TIC levels of the rocks. Co-occurrence networks suggest close interaction between chemolithoautotrophic and chemoorganotrophic/fermentative organisms. Carbon fixing 3-HP and DC/HB cycles, hydrogen, sulfur oxidation, CH4 and acetate metabolisms are predicted in the enriched communities. Our study elucidates the presence of live, C and H2 utilizing Bacteria and Archaea in deep subsurface granitic rocks, which are enriched successfully. Significant impact of depth and geochemical controls on relative distribution of various chemolithotrophic species enriched and their C and H2 metabolism are highlighted. These endolithic microorganisms show great potential for answering the fundamental questions of deep life and their exploitation in CO2 capture and conversion to useful products.
Collapse
Affiliation(s)
- Sunanda Mandal
- Environmental Microbiology and Biotechnology Laboratory, Department of Biotechnology, National Institute of Technology Durgapur, Durgapur, WB, India
| | - Himadri Bose
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, WB, India
| | - Kheerthana Ramesh
- Environmental Microbiology and Biotechnology Laboratory, Department of Biotechnology, National Institute of Technology Durgapur, Durgapur, WB, India
| | - Rajendra Prasad Sahu
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, WB, India
| | - Anumeha Saha
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, WB, India
| | - Pinaki Sar
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, WB, India
| | - Sufia Khannam Kazy
- Environmental Microbiology and Biotechnology Laboratory, Department of Biotechnology, National Institute of Technology Durgapur, Durgapur, WB, India,*Correspondence: Sufia Khannam Kazy,
| |
Collapse
|
16
|
Adam PS, Kolyfetis GE, Bornemann TLV, Vorgias CE, Probst AJ. Genomic remnants of ancestral methanogenesis and hydrogenotrophy in Archaea drive anaerobic carbon cycling. SCIENCE ADVANCES 2022; 8:eabm9651. [PMID: 36332026 PMCID: PMC9635834 DOI: 10.1126/sciadv.abm9651] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 09/19/2022] [Indexed: 05/19/2023]
Abstract
Anaerobic methane metabolism is among the hallmarks of Archaea, originating very early in their evolution. Here, we show that the ancestor of methane metabolizers was an autotrophic CO2-reducing hydrogenotrophic methanogen that possessed the two main complexes, methyl-CoM reductase (Mcr) and tetrahydromethanopterin-CoM methyltransferase (Mtr), the anaplerotic hydrogenases Eha and Ehb, and a set of other genes collectively called "methanogenesis markers" but could not oxidize alkanes. Overturning recent inferences, we demonstrate that methyl-dependent hydrogenotrophic methanogenesis has emerged multiple times independently, either due to a loss of Mtr while Mcr is inherited vertically or from an ancient lateral acquisition of Mcr. Even if Mcr is lost, Mtr, Eha, Ehb, and the markers can persist, resulting in mixotrophic metabolisms centered around the Wood-Ljungdahl pathway. Through their methanogenesis remnants, Thorarchaeia and two newly reconstructed order-level lineages in Archaeoglobi and Bathyarchaeia act as metabolically versatile players in carbon cycling of anoxic environments across the globe.
Collapse
Affiliation(s)
- Panagiotis S. Adam
- Environmental Microbiology and Biotechnology, Faculty of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
- Corresponding author.
| | - George E. Kolyfetis
- Environmental Microbiology and Biotechnology, Faculty of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15784 Athens, Greece
| | - Till L. V. Bornemann
- Environmental Microbiology and Biotechnology, Faculty of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
| | - Constantinos E. Vorgias
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15784 Athens, Greece
| | - Alexander J. Probst
- Environmental Microbiology and Biotechnology, Faculty of Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
- Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
- Research Center One Health Ruhr, Research Alliance Ruhr, Environmental Metagenomics, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
| |
Collapse
|
17
|
Thermophilic Water Gas Shift Reaction at High Carbon Monoxide and Hydrogen Partial Pressures in Parageobacillus thermoglucosidasius KP1013. FERMENTATION 2022. [DOI: 10.3390/fermentation8110596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The facultatively anaerobic Parageobacillus thermoglucosidasius oxidizes carbon monoxide to produce hydrogen via the water gas shift (WGS) reaction. In the current work, we examined the influence of carbon monoxide (CO) and hydrogen (H2) on the WGS reaction in the thermophilic P. thermoglucosidasius by cultivating two hydrogenogenic strains under varying CO and H2 compositions. Microbial growth and dynamics of the WGS reaction were monitored by evaluating parameters such as pressure, headspace composition, metabolic intermediates, pH, and optical density. Our analyses revealed that compared to the previously studied P. thermoglucosidasius strains, the strain KP1013 demonstrated higher CO tolerance and improved WGS reaction kinetics. Under anaerobic conditions, the lag phase before the WGS reaction shortened to 8 h, with KP1013 showing no hydrogen-induced product inhibition at hydrogen partial pressures up to 1.25 bar. The observed lack of product inhibition and the reduced lag phase of the WGS reaction support the possibility of establishing an industrial process for biohydrogen production with P. thermoglucosidasius.
Collapse
|
18
|
Leung PM, Daebeler A, Chiri E, Hanchapola I, Gillett DL, Schittenhelm RB, Daims H, Greening C. A nitrite-oxidising bacterium constitutively consumes atmospheric hydrogen. THE ISME JOURNAL 2022; 16:2213-2219. [PMID: 35752717 PMCID: PMC9381531 DOI: 10.1038/s41396-022-01265-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 05/27/2022] [Accepted: 06/07/2022] [Indexed: 11/08/2022]
Abstract
Chemolithoautotrophic nitrite-oxidising bacteria (NOB) of the genus Nitrospira contribute to nitrification in diverse natural environments and engineered systems. Nitrospira are thought to be well-adapted to substrate limitation owing to their high affinity for nitrite and capacity to use alternative energy sources. Here, we demonstrate that the canonical nitrite oxidiser Nitrospira moscoviensis oxidises hydrogen (H2) below atmospheric levels using a high-affinity group 2a nickel-iron hydrogenase [Km(app) = 32 nM]. Atmospheric H2 oxidation occurred under both nitrite-replete and nitrite-deplete conditions, suggesting low-potential electrons derived from H2 oxidation promote nitrite-dependent growth and enable survival during nitrite limitation. Proteomic analyses confirmed the hydrogenase was abundant under both conditions and indicated extensive metabolic changes occur to reduce energy expenditure and growth under nitrite-deplete conditions. Thermodynamic modelling revealed that H2 oxidation theoretically generates higher power yield than nitrite oxidation at low substrate concentrations and significantly contributes to growth at elevated nitrite concentrations. Collectively, this study suggests atmospheric H2 oxidation enhances the growth and survival of NOB amid variability of nitrite supply, extends the phenomenon of atmospheric H2 oxidation to an eighth phylum (Nitrospirota), and reveals unexpected new links between the global hydrogen and nitrogen cycles. Long classified as obligate nitrite oxidisers, our findings suggest H2 may primarily support growth and survival of certain NOB in natural environments.
Collapse
Affiliation(s)
- Pok Man Leung
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Anne Daebeler
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.
- Soil and Water Research Infrastructure, Biology Centre CAS, Budweis, Czechia.
| | - Eleonora Chiri
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Iresha Hanchapola
- Monash Proteomics and Metabolomics Facility and Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - David L Gillett
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Ralf B Schittenhelm
- Monash Proteomics and Metabolomics Facility and Department of Biochemistry, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Holger Daims
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.
- University of Vienna, The Comammox Research Platform, Vienna, Austria.
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
| |
Collapse
|
19
|
Ray AE, Zaugg J, Benaud N, Chelliah DS, Bay S, Wong HL, Leung PM, Ji M, Terauds A, Montgomery K, Greening C, Cowan DA, Kong W, Williams TJ, Hugenholtz P, Ferrari BC. Atmospheric chemosynthesis is phylogenetically and geographically widespread and contributes significantly to carbon fixation throughout cold deserts. THE ISME JOURNAL 2022; 16:2547-2560. [PMID: 35933499 PMCID: PMC9561532 DOI: 10.1038/s41396-022-01298-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 07/05/2022] [Accepted: 07/15/2022] [Indexed: 11/24/2022]
Abstract
Cold desert soil microbiomes thrive despite severe moisture and nutrient limitations. In Eastern Antarctic soils, bacterial primary production is supported by trace gas oxidation and the light-independent RuBisCO form IE. This study aims to determine if atmospheric chemosynthesis is widespread within Antarctic, Arctic and Tibetan cold deserts, to identify the breadth of trace gas chemosynthetic taxa and to further characterize the genetic determinants of this process. H2 oxidation was ubiquitous, far exceeding rates reported to fulfill the maintenance needs of similarly structured edaphic microbiomes. Atmospheric chemosynthesis occurred globally, contributing significantly (p < 0.05) to carbon fixation in Antarctica and the high Arctic. Taxonomic and functional analyses were performed upon 18 cold desert metagenomes, 230 dereplicated medium-to-high-quality derived metagenome-assembled genomes (MAGs) and an additional 24,080 publicly available genomes. Hydrogenotrophic and carboxydotrophic growth markers were widespread. RuBisCO IE was discovered to co-occur alongside trace gas oxidation enzymes in representative Chloroflexota, Firmicutes, Deinococcota and Verrucomicrobiota genomes. We identify a novel group of high-affinity [NiFe]-hydrogenases, group 1m, through phylogenetics, gene structure analysis and homology modeling, and reveal substantial genetic diversity within RuBisCO form IE (rbcL1E), and high-affinity 1h and 1l [NiFe]-hydrogenase groups. We conclude that atmospheric chemosynthesis is a globally-distributed phenomenon, extending throughout cold deserts, with significant implications for the global carbon cycle and bacterial survival within environmental reservoirs.
Collapse
|
20
|
Greening C, Grinter R. Microbial oxidation of atmospheric trace gases. Nat Rev Microbiol 2022; 20:513-528. [PMID: 35414013 DOI: 10.1038/s41579-022-00724-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2022] [Indexed: 02/06/2023]
Abstract
The atmosphere has recently been recognized as a major source of energy sustaining life. Diverse aerobic bacteria oxidize the three most abundant reduced trace gases in the atmosphere, namely hydrogen (H2), carbon monoxide (CO) and methane (CH4). This Review describes the taxonomic distribution, physiological role and biochemical basis of microbial oxidation of these atmospheric trace gases, as well as the ecological, environmental, medical and astrobiological importance of this process. Most soil bacteria and some archaea can survive by using atmospheric H2 and CO as alternative energy sources, as illustrated through genetic studies on Mycobacterium cells and Streptomyces spores. Certain specialist bacteria can also grow on air alone, as confirmed by the landmark characterization of Methylocapsa gorgona, which grows by simultaneously consuming atmospheric CH4, H2 and CO. Bacteria use high-affinity lineages of metalloenzymes, namely hydrogenases, CO dehydrogenases and methane monooxygenases, to utilize atmospheric trace gases for aerobic respiration and carbon fixation. More broadly, trace gas oxidizers enhance the biodiversity and resilience of soil and marine ecosystems, drive primary productivity in extreme environments such as Antarctic desert soils and perform critical regulatory services by mitigating anthropogenic emissions of greenhouse gases and toxic pollutants.
Collapse
Affiliation(s)
- Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia. .,Securing Antarctica's Environmental Future, Monash University, Clayton, Victoria, Australia. .,Centre to Impact AMR, Monash University, Clayton, Victoria, Australia.
| | - Rhys Grinter
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
| |
Collapse
|
21
|
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.
Collapse
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
| |
Collapse
|
22
|
Ortiz M, Leung PM, Shelley G, Jirapanjawat T, Nauer PA, Van Goethem MW, Bay SK, Islam ZF, Jordaan K, Vikram S, Chown SL, Hogg ID, Makhalanyane TP, Grinter R, Cowan DA, Greening C. Multiple energy sources and metabolic strategies sustain microbial diversity in Antarctic desert soils. Proc Natl Acad Sci U S A 2021; 118:e2025322118. [PMID: 34732568 PMCID: PMC8609440 DOI: 10.1073/pnas.2025322118] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2021] [Indexed: 12/11/2022] Open
Abstract
Numerous diverse microorganisms reside in the cold desert soils of continental Antarctica, though we lack a holistic understanding of the metabolic processes that sustain them. Here, we profile the composition, capabilities, and activities of the microbial communities in 16 physicochemically diverse mountainous and glacial soils. We assembled 451 metagenome-assembled genomes from 18 microbial phyla and inferred through Bayesian divergence analysis that the dominant lineages present are likely native to Antarctica. In support of earlier findings, metagenomic analysis revealed that the most abundant and prevalent microorganisms are metabolically versatile aerobes that use atmospheric hydrogen to support aerobic respiration and sometimes carbon fixation. Surprisingly, however, hydrogen oxidation in this region was catalyzed primarily by a phylogenetically and structurally distinct enzyme, the group 1l [NiFe]-hydrogenase, encoded by nine bacterial phyla. Through gas chromatography, we provide evidence that both Antarctic soil communities and an axenic Bacteroidota isolate (Hymenobacter roseosalivarius) oxidize atmospheric hydrogen using this enzyme. Based on ex situ rates at environmentally representative temperatures, hydrogen oxidation is theoretically sufficient for soil communities to meet energy requirements and, through metabolic water production, sustain hydration. Diverse carbon monoxide oxidizers and abundant methanotrophs were also active in the soils. We also recovered genomes of microorganisms capable of oxidizing edaphic inorganic nitrogen, sulfur, and iron compounds and harvesting solar energy via microbial rhodopsins and conventional photosystems. Obligately symbiotic bacteria, including Patescibacteria, Chlamydiae, and predatory Bdellovibrionota, were also present. We conclude that microbial diversity in Antarctic soils reflects the coexistence of metabolically flexible mixotrophs with metabolically constrained specialists.
Collapse
Affiliation(s)
- Maximiliano Ortiz
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa
| | - Pok Man Leung
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton VIC 3800, Australia;
| | - Guy Shelley
- School of Biological Sciences, Monash University, Clayton VIC 3800, Australia
| | - Thanavit Jirapanjawat
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton VIC 3800, Australia
| | - Philipp A Nauer
- School of Chemistry, Monash University, Clayton VIC 3800, Australia
| | - Marc W Van Goethem
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Sean K Bay
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton VIC 3800, Australia
- School of Biological Sciences, Monash University, Clayton VIC 3800, Australia
| | - Zahra F Islam
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton VIC 3800, Australia
- School of Biological Sciences, Monash University, Clayton VIC 3800, Australia
| | - Karen Jordaan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Surendra Vikram
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa
| | - Steven L Chown
- Securing Antarctica's Environmental Future, School of Biological Sciences, Monash University, Clayton VIC 3800, Australia
| | - Ian D Hogg
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa
- School of Science, University of Waikato, Hamilton 3240, New Zealand
- Polar Knowledge Canada, Canadian High Arctic Research Station, Cambridge Bay NU X0B 0C0, Canada
| | - Thulani P Makhalanyane
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa
| | - Rhys Grinter
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton VIC 3800, Australia
| | - Don A Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa;
| | - Chris Greening
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton VIC 3800, Australia;
- School of Biological Sciences, Monash University, Clayton VIC 3800, Australia
| |
Collapse
|
23
|
Candidatus Eremiobacterota, a metabolically and phylogenetically diverse terrestrial phylum with acid-tolerant adaptations. THE ISME JOURNAL 2021; 15:2692-2707. [PMID: 33753881 PMCID: PMC8397712 DOI: 10.1038/s41396-021-00944-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 02/11/2021] [Accepted: 02/18/2021] [Indexed: 02/01/2023]
Abstract
Candidatus phylum Eremiobacterota (formerly WPS-2) is an as-yet-uncultured bacterial clade that takes its name from Ca. Eremiobacter, an Antarctic soil aerobe proposed to be capable of a novel form of chemolithoautotrophy termed atmospheric chemosynthesis, that uses the energy derived from atmospheric H2-oxidation to fix CO2 through the Calvin-Benson-Bassham (CBB) cycle via type 1E RuBisCO. To elucidate the phylogenetic affiliation and metabolic capacities of Ca. Eremiobacterota, we analysed 63 public metagenome-assembled genomes (MAGs) and nine new MAGs generated from Antarctic soil metagenomes. These MAGs represent both recognized classes within Ca. Eremiobacterota, namely Ca. Eremiobacteria and UBP9. Ca. Eremiobacteria are inferred to be facultatively acidophilic with a preference for peptides and amino acids as nutrient sources. Epifluorescence microscopy revealed Ca. Eremiobacteria cells from Antarctica desert soil to be coccoid in shape. Two orders are recognized within class Ca. Eremiobacteria: Ca. Eremiobacterales and Ca. Baltobacterales. The latter are metabolically versatile, with individual members having genes required for trace gas driven autotrophy, anoxygenic photosynthesis, CO oxidation, and anaerobic respiration. UBP9, here renamed Ca. Xenobia class. nov., are inferred to be obligate heterotrophs with acidophilic adaptations, but individual members having highly divergent metabolic capacities compared to Ca. Eremiobacteria, especially with regard to respiration and central carbon metabolism. We conclude Ca. Eremiobacterota to be an ecologically versatile phylum with the potential to thrive under an array of "extreme" environmental conditions.
Collapse
|
24
|
Greening C, Islam ZF, Bay SK. Hydrogen is a major lifeline for aerobic bacteria. Trends Microbiol 2021; 30:330-337. [PMID: 34462186 DOI: 10.1016/j.tim.2021.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 12/31/2022]
Abstract
Molecular hydrogen (H2) is available in trace amounts in most ecosystems through atmospheric, biological, geochemical, and anthropogenic sources. Aerobic bacteria use this energy-dense gas, including at atmospheric concentrations, to support respiration and carbon fixation. While it was thought that aerobic H2 consumers are rare community members, here we summarize evidence suggesting that they are dominant throughout soils and other aerated ecosystems. Bacterial cultures from at least eight major phyla can consume atmospheric H2. At the ecosystem scale, H2 consumers are abundant, diverse, and active across diverse soils and are key primary producers in extreme environments such as hyper-arid deserts. On this basis, we propose that H2 is a universally available energy source for the survival of aerobic bacteria.
Collapse
Affiliation(s)
- Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Securing Antarctica's Environmental Future, Monash University, Clayton, VIC 3800, Australia; Centre to Impact AMR, Monash University, Clayton, VIC 3800, Australia.
| | - Zahra F Islam
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; STEM College, RMIT University, Bundoora, VIC 3083, Australia
| | - Sean K Bay
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; Securing Antarctica's Environmental Future, Monash University, Clayton, VIC 3800, Australia; School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| |
Collapse
|
25
|
Coskun ÖK, Vuillemin A, Schubotz F, Klein F, Sichel SE, Eisenreich W, Orsi WD. Quantifying the effects of hydrogen on carbon assimilation in a seafloor microbial community associated with ultramafic rocks. ISME JOURNAL 2021; 16:257-271. [PMID: 34312482 PMCID: PMC8692406 DOI: 10.1038/s41396-021-01066-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 07/05/2021] [Accepted: 07/09/2021] [Indexed: 11/09/2022]
Abstract
Thermodynamic models predict that H2 is energetically favorable for seafloor microbial life, but how H2 affects anabolic processes in seafloor-associated communities is poorly understood. Here, we used quantitative 13C DNA stable isotope probing (qSIP) to quantify the effect of H2 on carbon assimilation by microbial taxa synthesizing 13C-labeled DNA that are associated with partially serpentinized peridotite rocks from the equatorial Mid-Atlantic Ridge. The rock-hosted seafloor community was an order of magnitude more diverse compared to the seawater community directly above the rocks. With added H2, peridotite-associated taxa increased assimilation of 13C-bicarbonate and 13C-acetate into 16S rRNA genes of operational taxonomic units by 146% (±29%) and 55% (±34%), respectively, which correlated with enrichment of H2-oxidizing NiFe-hydrogenases encoded in peridotite-associated metagenomes. The effect of H2 on anabolism was phylogenetically organized, with taxa affiliated with Atribacteria, Nitrospira, and Thaumarchaeota exhibiting the most significant increases in 13C-substrate assimilation in the presence of H2. In SIP incubations with added H2, an order of magnitude higher number of peridotite rock-associated taxa assimilated 13C-bicarbonate, 13C-acetate, and 13C-formate compared to taxa that were not associated with peridotites. Collectively, these findings indicate that the unique geochemical nature of the peridotite-hosted ecosystem has selected for H2-metabolizing, rock-associated taxa that can increase anabolism under high H2 concentrations. Because ultramafic rocks are widespread in slow-, and ultraslow-spreading oceanic lithosphere, continental margins, and subduction zones where H2 is formed in copious amounts, the link between H2 and carbon assimilation demonstrated here may be widespread within these geological settings.
Collapse
Affiliation(s)
- Ömer K Coskun
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany
| | - Aurèle Vuillemin
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany.,GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
| | - Florence Schubotz
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Frieder Klein
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Susanna E Sichel
- Departamento de Geologia e Geofísica/LAGEMAR-Universidade Federal Fluminense-Brazil, Niterói, RJ, Brazil
| | - Wolfgang Eisenreich
- Department of Chemistry, Bavarian NMR Center-Structural Membrane Biochemistry, Technische Universität München, Garching, Germany
| | - William D Orsi
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany. .,GeoBio-CenterLMU, Ludwig-Maximilians-Universität München, Munich, Germany.
| |
Collapse
|
26
|
Termite gas emissions select for hydrogenotrophic microbial communities in termite mounds. Proc Natl Acad Sci U S A 2021; 118:2102625118. [PMID: 34285074 DOI: 10.1073/pnas.2102625118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Organoheterotrophs are the dominant bacteria in most soils worldwide. While many of these bacteria can subsist on atmospheric hydrogen (H2), levels of this gas are generally insufficient to sustain hydrogenotrophic growth. In contrast, bacteria residing within soil-derived termite mounds are exposed to high fluxes of H2 due to fermentative production within termite guts. Here, we show through community, metagenomic, and biogeochemical profiling that termite emissions select for a community dominated by diverse hydrogenotrophic Actinobacteriota and Dormibacterota. Based on metagenomic short reads and derived genomes, uptake hydrogenase and chemosynthetic RuBisCO genes were significantly enriched in mounds compared to surrounding soils. In situ and ex situ measurements confirmed that high- and low-affinity H2-oxidizing bacteria were highly active in the mounds, such that they efficiently consumed all termite-derived H2 emissions and served as net sinks of atmospheric H2 Concordant findings were observed across the mounds of three different Australian termite species, with termite activity strongly predicting H2 oxidation rates (R 2 = 0.82). Cell-specific power calculations confirmed the potential for hydrogenotrophic growth in the mounds with most termite activity. In contrast, while methane is produced at similar rates to H2 by termites, mounds contained few methanotrophs and were net sources of methane. Altogether, these findings provide further evidence of a highly responsive terrestrial sink for H2 but not methane and suggest H2 availability shapes composition and activity of microbial communities. They also reveal a unique arthropod-bacteria interaction dependent on H2 transfer between host-associated and free-living microbial communities.
Collapse
|
27
|
Trace gas oxidizers are widespread and active members of soil microbial communities. Nat Microbiol 2021; 6:246-256. [PMID: 33398096 DOI: 10.1038/s41564-020-00811-w] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/08/2020] [Indexed: 01/24/2023]
Abstract
Soil microorganisms globally are thought to be sustained primarily by organic carbon sources. Certain bacteria also consume inorganic energy sources such as trace gases, but they are presumed to be rare community members, except within some oligotrophic soils. Here we combined metagenomic, biogeochemical and modelling approaches to determine how soil microbial communities meet energy and carbon needs. Analysis of 40 metagenomes and 757 derived genomes indicated that over 70% of soil bacterial taxa encode enzymes to consume inorganic energy sources. Bacteria from 19 phyla encoded enzymes to use the trace gases hydrogen and carbon monoxide as supplemental electron donors for aerobic respiration. In addition, we identified a fourth phylum (Gemmatimonadota) potentially capable of aerobic methanotrophy. Consistent with the metagenomic profiling, communities within soil profiles from diverse habitats rapidly oxidized hydrogen, carbon monoxide and to a lesser extent methane below atmospheric concentrations. Thermodynamic modelling indicated that the power generated by oxidation of these three gases is sufficient to meet the maintenance needs of the bacterial cells capable of consuming them. Diverse bacteria also encode enzymes to use trace gases as electron donors to support carbon fixation. Altogether, these findings indicate that trace gas oxidation confers a major selective advantage in soil ecosystems, where availability of preferred organic substrates limits microbial growth. The observation that inorganic energy sources may sustain most soil bacteria also has broad implications for understanding atmospheric chemistry and microbial biodiversity in a changing world.
Collapse
|
28
|
Ertekin E, Meslier V, Browning A, Treadgold J, DiRuggiero J. Rock structure drives the taxonomic and functional diversity of endolithic microbial communities in extreme environments. Environ Microbiol 2020; 23:3937-3956. [PMID: 33078515 DOI: 10.1111/1462-2920.15287] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/07/2020] [Accepted: 10/18/2020] [Indexed: 11/29/2022]
Abstract
Endolithic (rock-dwelling) microbial communities are ubiquitous in hyper-arid deserts around the world and the last resort for life under extreme aridity. These communities are excellent models to explore biotic and abiotic drivers of diversity because they are of low complexity. Using high-throughput amplicon and metagenome sequencing, combined with X-ray computed tomography, we investigated how water availability and substrate architecture modulated the taxonomic and functional composition of gypsum endolithic communities in the Atacama Desert, Chile. We found that communities inhabiting gypsum rocks with a more fragmented substrate architecture had higher taxonomic and functional diversity, despite having less water available. This effect was tightly linked with community connectedness and likely the result of niche differentiation. Gypsum communities were functionally similar, yet adapted to their unique micro-habitats by modulating their carbon and energy acquisition strategies and their growth modalities. Reconstructed population genomes showed that these endolithic microbial populations encoded potential pathways for anoxygenic phototrophy and atmospheric hydrogen oxidation as supplemental energy sources.
Collapse
Affiliation(s)
- Emine Ertekin
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Victoria Meslier
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA.,MetaGenoPolis, Jouy-en-Josas, France
| | | | | | - Jocelyne DiRuggiero
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA.,Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, USA
| |
Collapse
|
29
|
Kucera J, Lochman J, Bouchal P, Pakostova E, Mikulasek K, Hedrich S, Janiczek O, Mandl M, Johnson DB. A Model of Aerobic and Anaerobic Metabolism of Hydrogen in the Extremophile Acidithiobacillus ferrooxidans. Front Microbiol 2020; 11:610836. [PMID: 33329503 PMCID: PMC7735108 DOI: 10.3389/fmicb.2020.610836] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 11/04/2020] [Indexed: 12/12/2022] Open
Abstract
Hydrogen can serve as an electron donor for chemolithotrophic acidophiles, especially in the deep terrestrial subsurface and geothermal ecosystems. Nevertheless, the current knowledge of hydrogen utilization by mesophilic acidophiles is minimal. A multi-omics analysis was applied on Acidithiobacillus ferrooxidans growing on hydrogen, and a respiratory model was proposed. In the model, [NiFe] hydrogenases oxidize hydrogen to two protons and two electrons. The electrons are used to reduce membrane-soluble ubiquinone to ubiquinol. Genetically associated iron-sulfur proteins mediate electron relay from the hydrogenases to the ubiquinone pool. Under aerobic conditions, reduced ubiquinol transfers electrons to either cytochrome aa 3 oxidase via cytochrome bc 1 complex and cytochrome c 4 or the alternate directly to cytochrome bd oxidase, resulting in proton efflux and reduction of oxygen. Under anaerobic conditions, reduced ubiquinol transfers electrons to outer membrane cytochrome c (ferrireductase) via cytochrome bc 1 complex and a cascade of electron transporters (cytochrome c 4, cytochrome c 552, rusticyanin, and high potential iron-sulfur protein), resulting in proton efflux and reduction of ferric iron. The proton gradient generated by hydrogen oxidation maintains the membrane potential and allows the generation of ATP and NADH. These results further clarify the role of extremophiles in biogeochemical processes and their impact on the composition of the deep terrestrial subsurface.
Collapse
Affiliation(s)
- Jiri Kucera
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czechia
| | - Jan Lochman
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czechia
| | - Pavel Bouchal
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czechia
| | - Eva Pakostova
- School of Biological Sciences, College of Natural Sciences, Bangor University, Bangor, United Kingdom
| | - Kamil Mikulasek
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Brno, Czechia
| | - Sabrina Hedrich
- Institute of Biosciences, Technische Universität (TU) Bergakademie Freiberg, Freiberg, Germany
| | - Oldrich Janiczek
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czechia
| | - Martin Mandl
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czechia
| | - D Barrie Johnson
- School of Biological Sciences, College of Natural Sciences, Bangor University, Bangor, United Kingdom
| |
Collapse
|
30
|
Jordaan K, Lappan R, Dong X, Aitkenhead IJ, Bay SK, Chiri E, Wieler N, Meredith LK, Cowan DA, Chown SL, Greening C. Hydrogen-Oxidizing Bacteria Are Abundant in Desert Soils and Strongly Stimulated by Hydration. mSystems 2020; 5:e01131-20. [PMID: 33203691 PMCID: PMC7677003 DOI: 10.1128/msystems.01131-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 10/29/2020] [Indexed: 01/19/2023] Open
Abstract
How the diverse bacterial communities inhabiting desert soils maintain energy and carbon needs is much debated. Traditionally, most bacteria are thought to persist by using organic carbon synthesized by photoautotrophs following transient hydration events. Recent studies focused on Antarctic desert soils have revealed, however, that some bacteria use atmospheric trace gases, such as hydrogen (H2), to conserve energy and fix carbon independently of photosynthesis. In this study, we investigated whether atmospheric H2 oxidation occurs in four nonpolar desert soils and compared this process to photosynthesis. To do so, we first profiled the distribution, expression, and activities of hydrogenases and photosystems in surface soils collected from the South Australian desert over a simulated hydration-desiccation cycle. Hydrogenase-encoding sequences were abundant in the metagenomes and metatranscriptomes and were detected in actinobacterial, acidobacterial, and cyanobacterial metagenome-assembled genomes. Native dry soil samples mediated H2 oxidation, but rates increased 950-fold following wetting. Oxygenic and anoxygenic phototrophs were also detected in the community but at lower abundances. Hydration significantly stimulated rates of photosynthetic carbon fixation and, to a lesser extent, dark carbon assimilation. Hydrogenase genes were also widespread in samples from three other climatically distinct deserts, the Namib, Gobi, and Mojave, and atmospheric H2 oxidation was also greatly stimulated by hydration at these sites. Together, these findings highlight that H2 is an important, hitherto-overlooked energy source supporting bacterial communities in desert soils. Contrary to our previous hypotheses, however, H2 oxidation occurs simultaneously rather than alternately with photosynthesis in such ecosystems and may even be mediated by some photoautotrophs.IMPORTANCE Desert ecosystems, spanning a third of the earth's surface, harbor remarkably diverse microbial life despite having a low potential for photosynthesis. In this work, we reveal that atmospheric hydrogen serves as a major previously overlooked energy source for a large proportion of desert bacteria. We show that both chemoheterotrophic and photoautotrophic bacteria have the potential to oxidize hydrogen across deserts sampled across four continents. Whereas hydrogen oxidation was slow in native dry deserts, it increased by three orders of magnitude together with photosynthesis following hydration. This study revealed that continual harvesting of atmospheric energy sources may be a major way that desert communities adapt to long periods of water and energy deprivation, with significant ecological and biogeochemical ramifications.
Collapse
Affiliation(s)
- Karen Jordaan
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Rachael Lappan
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Xiyang Dong
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, China
| | - Ian J Aitkenhead
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Sean K Bay
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Eleonora Chiri
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | | | - Laura K Meredith
- School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona, USA
| | - Don A Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Steven L Chown
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| |
Collapse
|
31
|
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.
Collapse
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
| |
Collapse
|