Fermentation of maleate by a gram-negative strictly anaerobic non-spore-former, Propionivibrio dicarboxylicus gen. nov., sp. nov

Three strains of maleate-fermenting anaerobic curved rods were isolated in pure culture from anaerobic freshwater mud samples. Among the isolates, strain CreMal1 was studied in detail. It was a mesophilic non-sporing gram-negative strict anaerobe, and grew not only on maleate but also on fumarate and L-malate, producing propionate and acetate stoichiometrically as end products. Succinate was an intermediate in the degradation of maleate. Strain CreMal1 is described as a member of Propionivibrio dicarboxylicus gen. nov., sp. nov., in the family Bacteroidaceae.