Aminomonas paucivorans gen. nov., sp nov., a mesophilic anaerobic, amino-acid-utilizing bacterium

A novel, asaccharolytic, amino-acid-degrading bacterium, designated strain GLU-3(T), was isolated from an anaerobic lagoon of a dairy wastewater treat ment plant. Strain GLU-3(T) stained Gram-negative and was an obligately ana erobic, non-spore-forming, slightly curved, rod-shaped bacterium (0.3 x 4.0 -6.0 mu m) which existed singly or in pairs. The DNA G+C content was 43 mol %. Optimum growth occurred at 35 degrees C and pH 7.5 on arginine with a ge neration time of 16 h. Good growth was obtained on arginine, histidine, gen eration time of 16 h. Good growth was obtained on arginine, histidine, thre onine and glycine. Acetate was the end-product formed from all these substr ates, but in addition, a trace of formate was detected from arginine and hi stidine, and ornithine was produced from arginine. Strain GLU-3(T) grew slo wly on glutamate and produced acetate, carbon dioxide, formate, hydrogen an d traces of propionate as the end-products. In syntrophic association with Methanobacterium formicicum, strain GLU-3(T) oxidized arginine, histidine a nd glutamate to give propionate as the major product; acetate, carbon dioxi de and methane were also produced. Strain GLU-3(T) did not degrade alanine and the branched-chain amino acids valine, leucine and isoleucine either in pure culture or in association with M. formicicum. The nearest phylogeneti c relative of strain GLU-3(T) was the thermophile Selenomonas acidaminovora ns (similarity value of 89.5 %). As strain GLU-3(T) is phylogenetically, ph ysiologically and genotypically different from other amino-acid-degrading g enera, it is proposed that it should be designated a new species of a new g enus Aminomonas paucivorans gen. nov., sp. nov. (DSM 12260(T)).