Bacillus oleivorans sp. nov., a diesel oil-degrading and solvent-tolerant bacterium.

Abstract

Two Gram-stain-positive, diesel oil-degrading, solvent-tolerant, aerobic, endospore-forming, rod-shaped bacteria were isolated from a contaminated laboratory plate. Based on 16S rRNA gene sequence analysis, strains JC228(T) and JC279 were identified as belonging to the genus Bacillus within the family Bacillaceae of the phylum Firmicutes and were found to be most closely related to Bacillus carboniphilus JCM 9731(T) (98.1% 16S rRNA gene sequence similarity) and shared <96.0% 16S rRNA gene sequence similarity with other members of the genus Bacillus . The DNA-DNA hybridization value between the two strains was 88±2%. Strain JC228(T) showed 23.4±1% reassociation (based on DNA-DNA hybridization) with B. carboniphilus LMG 18001(T). The DNA G+C content of strains JC228(T) and JC279 was 39 and 38.4 mol%, respectively. Both strains were positive for catalase and oxidase activities, and negative for hydrolysis of starch and Tween 80. Strains JC228(T) and JC279 grew chemoorganoheterotrophically with optimum growth at pH 7 (range pH 7-9.5) and 35 °C (range 25-40 °C). Diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and an unidentified phospholipid (PL2) were the major polar lipids. Major cellular fatty acids were iso-C(15 : 0), anteiso-C(15 : 0), iso-C(17 : 0) and C(16 : 0). Whole-cell hydrolysates contained l-alanine, d-alanine, d-glutamic acid and meso-diaminopimelic acid. Both strains utilized diesel oil as sole carbon and energy source. The results of physiological, biochemical, chemotaxonomic and molecular analyses allowed clear differentiation of strains JC228(T) and JC279 from their closest phylogenetic neighbours. Therefore strains JC228(T) and JC279 represent a novel species of the genus Bacillus , for which the name Bacillus oleivorans sp. nov. is proposed. The type strain is JC228(T) ( = LMG 28084(T) = CCTCC AB 2013353(T)).