Anaerostipes rhamnosivorans sp. nov., a human intestinal butyrate forming bacterium

A novel butyrate producing bacterium, strain 1y-2T, was isolated from a stool sample of a 1-year old, healthy Dutch infant. The isolate was obtained by using lactate and acetate as sources of carbon and energy. The strain was Gram-variable, strictly anaerobic, spore-forming and formed curly rod-shaped cells that fermented glucose into butyrate, lactate, formate and acetate as main products. The G + C composition of the strain was 44.5 % and its major cellular fatty acids were C12:00, C19:1 iso I and C16:00. Strain 1y-2T was related to Anaerostipes caccae DSM14662T based on 16S rRNA analysis with 3 % divergence but hybridization studies of their genomic DNA revealed only 33 % similarity. Moreover, strain 1y-2T showed marked physiological and biochemical differences with known Anaerostipes species. Based on the phylogenetic, chemotypic and phenotypic criteria, we propose that strain 1y-2T should be classified in the genus Anaerostipes as a novel species, Anaerostipes rhamnosivorans sp. nov. The type strain is 1y-2T (= DSM 26241T = KCTC 15316T