Flavobacterium olei sp. nov., a novel psychrotolerant bacterium isolated from oil-contaminated soil.

During a study of psychrophilic hydrocarbon-degrading bacteria, two yellow, Gram-staining-negative, non-motile, and rod shaped bacteria, designated R-10-9T and K-4-2 were isolated from oil-contaminated soil from Ulaanbaatar, Mongolia. Both strains were able to grow at 0-32 °C, pH 5.0-9.5, and 0-1 % (w/v) NaCl concentration. These strains were taxonomically characterized by a polyphasic approach. On the basis of the results of 16S rRNA gene sequence analysis, R-10-9T and K-4-2 belong to the genus Flavobacterium and are closely related to Flavobacterium oncorhynchi 631-08T (97.80 and 98.09 % sequence similarity, respectively). The pairwise sequence similarity between R-10-9T and K-4-2 was observed to be 99.72 %. In both strains, the predominant respiratory quinone was menaquinone-6; the major polar lipid was phosphatidylethanolamine; and the major fatty acids were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C15 : 0, C16 : 0 3-OH, antesio-C15 : 0, C16 : 0, iso-C17 : 0 3-OH, and iso-C15 : 0 3-OH. The genomic DNA G+C contents of R-10-9T and K-4-2 were 35.9 and 35.4 mol%, respectively. The DNA-DNA relatedness between R-10-9T and K-4-2 was higher than 70 % but relatedness values with closely related reference strains were less than 35 %. The morphological, physiological, chemotaxonomic, and phylogenetic analyses clearly distinguished R-10-9T from its closest phylogenetic neighbours. Thus, R-10-9T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium olei sp. nov. is proposed. The type strain is R-10-9T (=KEMB 9005-447T=KACC 18997T=JCM 31673T), and strain K-4-2 as an additional strain.