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Atmospheric hydrogen scavenging: From enzymes to ecosystems

Greening, Chris; Constant, Philippe; Hards, Kiel; Morales, Sergio E.; Oakeshott, John G.; Russell, Robyn J.; Taylor, Matthew C.; Berney, Michael; Conrad, Ralf; Cookb, Gregory M. (2015). Atmospheric hydrogen scavenging: From enzymes to ecosystems Applied and Environmental Microbiology , vol. 81 , nº 4. p. 1190-1199. DOI: 10.1128/AEM.03364-14.

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Résumé

We have known for 40 years that soils can consume the trace amounts of molecular hydrogen (H2) found in the Earth's atmosphere. This process is predicted to be the most significant process in the global hydrogen cycle. However, the organisms and enzymes responsible for this process were only recently identified. Pure culture experiments demonstrated that several species of Actinobacteria, including streptomycetes and mycobacteria, can couple the oxidation of atmospheric H2 to the reduction of ambient O2. A combination of genetic, biochemical, and phenotypic studies suggest that these organisms primarily use this fuel source to sustain electron input into the respiratory chain during energy-starvation. This process is mediated by a specialized enzyme, the Group 5 [NiFe]-hydrogenase, which is unusual for its high-affinity, oxygen-insensitivity, and thermostability. Atmospheric hydrogen scavenging is a particularly dependable mode of energy-generation, given both the ubiquity of the substrate and the stress-tolerance of its catalyst. This review summarizes the recent progress in understanding how and why certain organisms scavenge atmospheric H2. In addition, it provides insight into the wider significance of hydrogen scavenging in global H2 cycling and soil microbial ecology.

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Centre: Centre INRS-Institut Armand Frappier
Date de dépôt: 10 mars 2016 15:38
Dernière modification: 10 mars 2016 15:38
URI: http://espace.inrs.ca/id/eprint/3194

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