Microbial manganese(III) reduction fuelled by anaerobic acetate oxidation. (17th July 2017)

• Record Type: Journal Article
• Authors: Szeinbaum, Nadia; Lin, Hui; Brandes, Jay A.; Taillefert, Martial; Glass, Jennifer B.; DiChristina, Thomas J.
• Is Part Of: Environmental microbiology. Volume 19:Number 9(2017:Sep.)
• Page Start: 3475
• Page End: 3486
• Publication Date: 2017-07-17
• Subjects: Microbial ecology -- Periodicals; Environmental Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1462-2920.13829
• Languages: English
• ISSNs: 1462-2912

Abstract

Summary: Soluble manganese in the intermediate +III oxidation state (Mn 3+ ) is a newly identified oxidant in anoxic environments, whereas acetate is a naturally abundant substrate that fuels microbial activity. Microbial populations coupling anaerobic acetate oxidation to Mn 3+ reduction, however, have yet to be identified. We isolated a Shewanella strain capable of oxidizing acetate anaerobically with Mn 3+ as the electron acceptor, and confirmed this phenotype in other strains. This metabolic connection between acetate and soluble Mn 3+ represents a new biogeochemical link between carbon and manganese cycles. Genomic analyses uncovered four distinct genes that allow for pathway variations in the complete dehydrogenase‐driven TCA cycle that could support anaerobic acetate oxidation coupled to metal reduction in Shewanella and other Gammaproteobacteria. An oxygen‐tolerant TCA cycle supporting anaerobic manganese reduction is thus a new connection in the manganese‐driven carbon cycle, and a new variable for models that use manganese as a proxy to infer oxygenation events on early Earth.