Aquabacterium olei sp. nov., an oil-degrading bacterium isolated from oil-contaminated soil.

Strain NHI-1T is a Gram-negative, motile, non-spore-forming bacterium isolated from oil-contaminated soil in South Korea. The strain was able to grow by using gasoline, diesel and kerosene as energy and carbon sources. After incubation for 14 days, cells (1 g l- 1) degraded approximately 58 % of oil present at concentration of 1500 p.p.m. at pH 8 and 28 °C. Strain NHI-1T grew well under aerobic conditions, with optimal growth at pH 7-9 and 28 °C-37 °C but grew poorly in the presence of ≥ 0.5 % NaCl. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the closest relatives of strain NHI-1T were Aquabacterium fontiphilum CS-6T (97.96 % sequence similarity), Aquabacterium parvum B6T (96.39 %), Aquabacterium commune B8T (95.76 %), Aquabacterium limnoticum ABP-4T (95.72 %) and Aquabacterium citratiphilum B4T (95.25 %). DNA-DNA relatedness was 41-53 % between strain NHI-1T and its closest type strains. The major fatty acids present in strain NHI-1T were summed feature 3 (C16 : 1ω7c/C16 : 1ω6c, 44.5 %), summed feature 8 (C18 : 1ω7c/C18 : 1ω6c, 21.5 %) and C16 : 0 (16.2 %), and the predominant polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylserine, diphosphatidylglycerol and uncharacterized aminophospholipids. Strain NHI-1T was distinguishable from other members of genus Aquabacterium based on phenotypic, chemotaxonomic and genotypic characteristics. Therefore, strain NHI-1T represents a novel species of the genus Aquabacterium for which the name Aquabacterium olei sp. nov. is proposed. The type strain is NHI-1T ( = KEMB 9005-082T =  KACC 18244T = NBRC 110486T).