Isolation and characterization of a thermophilic, acetate-utilizing methanogenic bacterium

Abstract A thermophilic acetate-decarboxylating methanogenic bacterium was isolated from a laboratory-scale 60°C sludge digestor. Cells form straight filaments with flat to blunted ends normally consisting of 2–3 cells held together by a sheath-like outer cell wall. The organism uses acetate, H₂-CO₂ and formate for methanogenesis and growth. With acetate as the sole methanogenic substrate, almost all of the radioactivity from methyl-labelled acetate appeared as methane. Acetate was converted to methane in equimolar amounts with a doubling time of 3 days.