Sporomusa malonica sp. nov., a homoacetogenic bacterium growing by decarboxylation of malonate or succinate

Abstract

A new strictly anaerobic bacterium was isolated from an enrichment culture with glutarate as sole substrate and freshwater sediment as inoculum, however, glutarate was not metabolized by the pure culture. The isolate was a mesophilic, spore-forming, Gram-negative, motile curved rod. It fermented various organic acids, alcohols, fructose, acetoin, and H2/CO2 to acetate, usually as the only product. Other acids were fermented to acetate and propionate or acetate and butyrate. Succinate and malonate were decarboxylated to propionate or acetate, respectively, and served as sole sources of carbon and energy for growth. No inorganic electron acceptors except CO2 were reduced. Yeast extract (0.05% w/v) was required for growth. Small amounts of cytochrome b were detected in membrane fractions. The guanine-plus-cytosine content of the DNA was 44.1±2 mol%. The isolate is described as a new species of the genus Sporomusa, S. malonica.