Romboutsia sedimentorum sp nov., isolated from an alkaline-saline lake sediment and emended description of the genus Romboutsia

A Gram-stain-positive, spore-forming, obligately anaerobic bacterium, designated LAM201(T), was isolated from sediment samples from an alkaline-saline lake located in Daqing oilfield, Daqing City, PR China. Cells of strain LAM201(T) were non-motile and straight or spiral rod-shapes. Strain LAM201(T) was able to utilize glucose, fructose, maltose, trehalose and sorbitol as the sole carbon source. Acetic acid, ethanol, iso-butanoic acid and iso-valeric acid were the main products of glucose fermentation. The major fatty acids of LAM201(T) were C-16:0 (26.7%) and C-18:0 (11.2 %). The main polar lipids were four unknown glycolipids and five unknown phospholipids. The predominant cell-wall sugars were ribose and galactose. The cell-wall peptidoglycan of strain LAM201(T) contained alanine, glycine, glutamic acid and aspartic acid. Sodium sulfite was used as the electron acceptor. The G+C content of the genomic DNA was 32 +/- 0.8 mol%, as determined by the T-m method. Analysis of the 16S rRNA gene sequence indicated that the isolate belonged to the genus Romboutsia and was most closely related to Romboutsia lituseburensis DSM 797(T) and Romboutsia ilealis CRIBT with 97.3% and 97.2% similarities, respectively. The DNA-DNA hybridization values between strain LAM201(T) and the two reference strains were 37 % and 31 %, respectively. On the basis of its phenotypic, phylogenetic and chemotaxonomic characteristics, strain LAM201(T) is suggested to represent a novel species within the genus Romboutsia, for which the name Romboutsia sedimentorum sp. nov. is proposed. The type strain is LAM201(T) (=ACCC 00717(T)=JCM 19607(T)).