Sphingopyxis nepalensis sp. nov., isolated from oil-contaminated soil

During a study of oil-degrading bacteria, three yellow-coloured, Gram-stain-negative, non-motile and rod-shaped bacteria, designated strains Ktm-14^T, Ktm-17 and Ktm-18, were isolated from oil-contaminated soil of Biratnagar, Morang, Nepal. The strains were able to grow at 15-37 °C, pH 4.5-10.0 and 0-2 % (w/v) NaCl concentration. Strains Ktm-14^T, Ktm-17 and Ktm-18 were characterized by multiple taxonomic approaches. Based on 16S rRNA gene sequence analysis, strains Ktm-14^T, Ktm-17 and Ktm-18 belonged to the genus Sphingopyxis and shared highest sequence similarity with Sphingopyxis ginsengisoliGsoil 250^T (98.94 %). The only respiratory quinone was ubiquinone-10 and the predominant polyamine was spermidine. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, phosphatidylmonomethylethanolamine and sphingoglycolipids. The predominant fatty acids were C17 : 1ω6c, summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The DNA G+C content values of strains Ktm-14^T, Ktm-17 and Ktm-18 were 65.8, 65.9 and 65.6 mol%, respectively. The DNA-DNA relatedness between Ktm-14^T and Ktm-17 and Ktm-18 were higher than 70 % but with closely related reference strains were less than 40 %. The morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished strain Ktm-14^T from its closest phylogenetic neighbours. Thus, strain Ktm-14^T represents a novel species of the genus Sphingopyxis, for which the name Sphingopyxisnepalensis sp. nov. is proposed. The type strain is Ktm-14^T (=KEMB 9005-694^T=KACC 19389^T=JCM 32250^T), and strains Ktm-17 and Ktm-18 represent two additional strains.