Rhodococcus olei sp. nov., with the ability to degrade petroleum oil, isolated from oil-contaminated soil

A Gram-stain-positive, non-motile, creamy-white and rod-coccus shaped actinobacterium, designated strain Ktm-20 T , capable of degrading petroleum oil was isolated from oil-contaminated soil. Strain Ktm-20 T was able to grow at 15-37 °C, at pH 5.5-10.0 and at 0.0-2.0 % (w/v) NaCl concentration. This strain was taxonomically characterized by a polyphasic approach. The 16S rRNA gene sequence analysis showed that strain Ktm-20 T belonged to the genus Rhodococcus and is closely related to Rhodococcus triatomae DSM 44892 T , Rhodococcus pedocola UC12 T , Rhodococcus wratislaviensis NBRC 100605 T , Rhodococcus agglutinans CFH S0262 T and Rhodococcus canchipurensis MBRL 353T (98.8, 98.7, 98.5, 98.4 and 98.3 % gene sequence similarity, respectively). The only respiratory quinone was MK-8(H2); the major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside; and the predominant fatty acids were C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C18 : 1ω9c. The cell-wall peptidoglycan contained meso-diaminopimelic acid; and galactose, glucose, arabinose and ribose were detected as diagnostic sugars from whole-cell hydrolysates. Mycolic acids were detected. The DNA G+C content was 70.9 mol%. The DNA-DNA relatedness values between strain Ktm-20 T and closely related species of the genus Rhodococcus were between 38.3-25.3 %, which falls below the threshold value of 70 % for the strain to be considered as novel. The morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbours. Thus, strain Ktm-20 T represents a novel species of the genus Rhodococcus, for which the name Rhodococcus olei sp. nov. is proposed. The type strain is Ktm-20 T (=KEMB 9005-695 T =KACC 19390 T =JCM 32206 T ).