Hydrogenase-independent uptake and metabolism of electrons by the archaeon Methanococcus maripaludis

Svenja T. Lohner, Jörg S. Deutzmann, Bruce E. Logan, John Leigh, Alfred M. Spormann

Research output: Contribution to journalArticlepeer-review

137 Scopus citations

Abstract

Direct, shuttle-free uptake of extracellular, cathode-derived electrons has been postulated as a novel mechanism of electron metabolism in some prokaryotes that may also be involved in syntrophic electron transport between two microorganisms. Experimental proof for direct uptake of cathodic electrons has been mostly indirect and has been based on the absence of detectable concentrations of molecular hydrogen. However, hydrogen can be formed as a transient intermediate abiotically at low cathodic potentials (<-414 mV) under conditions of electromethanogenesis. Here we provide genetic evidence for hydrogen-independent uptake of extracellular electrons. Methane formation from cathodic electrons was observed in a wild-type strain of the methanogenic archaeon Methanococcus maripaludis as well as in a hydrogenase-deletion mutant lacking all catabolic hydrogenases, indicating the presence of a hydrogenase-independent mechanism of electron catabolism. In addition, we discovered a new route for hydrogen or formate production from cathodic electrons: Upon chemical inhibition of methanogenesis with 2-bromo-ethane sulfonate, hydrogen or formate accumulated in the bioelectrochemical cells instead of methane. These results have implications for our understanding on the diversity of microbial electron uptake and metabolism.

Original languageEnglish (US)
Pages (from-to)1673-1681
Number of pages9
JournalISME Journal
Volume8
Issue number8
DOIs
StatePublished - Aug 2014

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Ecology, Evolution, Behavior and Systematics

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