Lawsonibacter asaccharolyticus gen. nov., sp. nov., a butyrate-producing bacterium isolated from human faeces.

An obligately anaerobic, Gram-positive, non-spore-forming, straight rod-shaped bacterium, designated strain 3BBH22T , was isolated from a faecal sample of a healthy Japanese woman. The 16S rRNA gene sequence analysis showed that strain 3BBH22T formed a monophyletic cluster with species in the genera Pseudoflavonifractor and Flavonifractor within the family Ruminococcaceae and had highest similarity to Pseudoflavonifractor capillosus ATCC 29799T (96.7 % sequence similarity), followed by Flavonifractor plautii ATCC 29863T (96.4 %). Acetate and butyrate were produced by strain 3BBH22T as metabolic end-products. The major cellular fatty acids were C14 : 0, C16 : 0, C18 : 1ω9c, C16 : 0 dimethyl acetal, C18 : 0 and C18 : 2ω6,9c. No respiratory quinones were detected. In contrast to F. plautii JCM 32125T , strain 3BBH22T did not degrade quercetin, one of the flavonoids. P. capillosus JCM 32126T also did not. Strain 3BBH22T was differentiated from P. capillosus JCM 32126T by its inability to hydrolyse aesculin. The G+C content of the genomic DNA was 61.2±1.0 mol%. On the basis of these data and the phylogenetic tree based on 89 proteins, strain 3BBH22T represents a novel species in a novel genus of the family Ruminococcaceae, for which the name Lawsonibacter asaccharolyticus gen. nov., sp. nov. is proposed. The type strain of L. asaccharolyticus is 3BBH22T (=JCM 32166T =DSM 106493T ).