Abstract

Bacterial strain Eg2T, an anaerobic, Gram-positive, non-motile, and non-spore-forming coccus, was isolated from human faeces. The optimal temperature for its growth was 37°C. Oxidase activity was negative, but catalase activity was positive. The strain was able to hydrolyze esculin and to produce acids from the fermentation of several substrates, including glucose. Lactic and acetic acids were the main products of glucose fermentation. The major fatty acids present in this strain were C16:0, C14:0, and C18:1 cis11 DMA. The G+C content was 43.4 mol%. Based on the 16S rRNA gene sequence, strain Eg2T was closely related to species of the genus Ruminococcus (96.3% similarity to R. torques and 96.2% similarity to R. lactaris), and its taxonomic position was placed within the Clostridium cluster XIVa. Based on phenotypic, chemotaxonomic, genotypic, and phylogenetic evidence, we propose that this novel strain be assigned to the genus Ruminococcus and be named Ruminococcus faecis sp. nov. The type strain is Eg2T (=KCTC 5757T =JCM 15917T).

• Keywords: gut bacteria; clostridium cluster XIVa; Ruminococcus faecis sp. nov.; taxonomy