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 CRIB^T 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).