Syntrophic Acetate Oxidation and “Reversible Acetogenesis”

Abstract

Acetate is an important CH4 precursor in nature, accounting for two-thirds of the CH4 produced in many natural habitats and in anaerobic bioreactors. Although microbial methanogenesis from acetate was first described in the early 1900s, the mechanism of methanogenesis from acetate was controversial until 1978, when it was demonstrated that a pure culture of Methanosarcina barkeri could grow on acetate (Mah et al., 1978; Smith and Mah, 1978; Weimer and Zeikus, 1978) and convert acetate to CH4 by a decarboxylation mechanism sometimes called the aceticlastic reaction. With the description of a similar mechanism for Methanothrix soehngenii in 1980 (Zehnder et al., 1980), it appeared that acetate decarboxylation was “the” mechanism for methanogenesis from acetate.