Agathobaculum butyriciproducens gen. nov sp nov., a strict anaerobic, butyrate-producing gut bacterium isolated from human faeces and reclassification of Eubacterium desmolans as Agathobaculum desmolans comb. nov.

A novel bacterial strain, SR79(T), was isolated from a Korean faecal sample and characterized using a polyphasic approach. SR79(T) was found to be a strictly anaerobic, Gram-stain-positive, non-spore-forming, non-motile, catalase-and oxidase-negative short rod with no flagella. SR79(T) grew optimally at 37 degrees C in the presence of 0.5% (w/v) NaCl at pH 7. The NaCl range for growth was 0-1% (w/v). The isolate produced butyric acid (> 18 mM) as a major end product. A phylogenetic analysis based on 16S rRNA gene sequences revealed that the most closely related type strains were Eubacterium desmolans ATCC 43058(T) and Butyricicoccus pullicaecorum 25-3(T) (96.4 and 96.0% similarity, respectively). The DNA G+C content was determined to be 52.9 mol%. The major cellular fatty acids (> 10 %) were C-16 (:) (0), C-18 : (1) cis-9, C-19 (:) (1) cyc 9,10 and C-14 (:) (0). Meso-diaminopimelic acid was present in the cell wall peptidoglycan and the cell wall hydrolysates contained ribose, glucose and galactose. The 16S rRNA gene sequence similarity, phylogenetic analysis, chemotaxonomic and phenotypic characteristics allowed differentiation of SR79(T), which represents a novel species of a new genus within the family Ruminococcaceae, for which the name Agathobaculum butyriciproducens gen. nov. sp. nov. is proposed. The type strain is SR79(T) (=KCTC 15532(T) =DSM 100391(T)). Based on the results of this study, it is also proposed to transfer Eubacterium desmolans to this new genus, as Agathobaculum desmolans comb. nov. The type strain of Agathobaculum desmolans is ATCC 43058(T) (=CCUG 27818(T)).