Life on the thermodynamic edge: Respiratory growth of an acetotrophic methanogen

Divya Prakash, Shikha S. Chauhan, James G. Ferry

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Although two-thirds of the nearly 1 billion metric tons of methane produced annually in Earth’s biosphere derives from acetate, the in situ process has escaped rigorous understanding. The unresolved question concerns the mechanism by which the exceptionally marginal amount of available energy supports acetotrophic growth of methanogenic archaea in the environment. Here, we show that Methanosarcina acetivorans conserves energy by Fe(III)-dependent respiratory metabolism of acetate, augmenting production of the greenhouse gas methane. An extensively revised, ecologically relevant, biochemical pathway for acetotrophic growth is presented, in which the conservation of respiratory energy is maximized by electron bifurcation, a previously unknown mechanism of biological energy coupling. The results transform the ecological and biochemical understanding of methanogenesis and the role of iron in the mineralization of organic matter in anaerobic environments.

Original languageEnglish (US)
Article numbereaaw9059
JournalScience Advances
Volume5
Issue number8
DOIs
StatePublished - Aug 21 2019

All Science Journal Classification (ASJC) codes

  • General

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