Aminobacterium colombiense gen. nov. sp. nov., an amino acid-degrading anaerobe isolated from anaerobic sludge

A new Gram-negative, non-sporulating, mesophilic, amino acid-fermenting bacterium, designated strain ALA-1(T) (T = type strain), was isolated from an anaerobic lagoon of a dairy wastewater treatment plant. The strain is curved (3-4 μm x 0.2-0.3 μm) and occurs singly or in pairs. Optimum growth occurs at 37°C and pH 7.3. The G + C content of the DNA is 46 mol %. The strain requires yeast extract for growth, grows poorly on casamino acids, peptones, cystein, and α-ketoglutarate, but readily grows on serine, threonine, glycine and pyruvate. When cocultured with the hydrogenotrophic methanogen Methanobacterium formicicum, strain ALA-1(T) oxidized alanine, glutamate, leucine, isoleucine, valine, aspartate, and methionine. Phylogenetic analysis revealed that it forms a distinct and independent line of descent in the vicinity of Dethiosulfovibrio peptidovorans, Dictyoglomus thermophilum, and Anaerobaculum thermoterrenum which are members of the low G + C containing Gram-positive bacteria. The phylogenetic results concur with the phenotypic and genomic data which reveal that it is a novel strain. Based on these findings, we designate strain ALA-1(T) as Aminobacterium colombiense (DSM 12261) gen. nov., sp. nov.