Proteiniborus ethanoligenes gen. nov., sp. nov., an anaerobic protein-utilizing bacterium.

A novel anaerobic, mesophilic, protein-utilizing bacterial strain, GW(T), was isolated from the mesophilic hydrogen-producing granular sludge used to treat food industry wastewater. The strain was a Gram-positive, non-spore-forming and non-motile rod. Growth of the strain was observed at 20-48 degrees C and at pH 6.4-10.0. The strain used yeast extract and peptone as carbon and energy sources. Weak growth was also observed with tryptone and Casamino acids as carbon and energy sources. The strain used none of the tested carbohydrates, alcohols or fatty acids. The fermentation products in peptone-yeast broth included ethanol, acetic acid, hydrogen and carbon dioxide. Gelatin was not hydrolysed. Nitrate was reduced. Indole was produced. NH(3) and H(2)S were not produced. The DNA G+C content of strain GW(T) was 38.0 mol%. The predominant cellular fatty acids were the saturated fatty acids C(14:0) (15.58%), C(16:0) (25.40%) and C(18:0) (12.03%). Phylogenetic analysis based on 16S rRNA gene sequence similarity revealed that strain GW(T) represented a new branch within cluster XII of the Clostridium subphylum, with <89.6% 16S rRNA gene sequence similarities to all described species. On the basis of polyphasic evidence from this study, strain GW(T) represents a new genus and novel species, for which the name Proteiniborus ethanoligenes gen. nov., sp. nov. is proposed. The type strain is GW(T) (=CGMCC 1.5055(T)=JCM 14574(T)).