Alcanivorax xenomutans sp. nov., a hydrocarbonoclastic bacterium isolated from a shrimp cultivation pond.

Two bacterial strains (JC109(T) and JC261) were isolated from a sediment sample collected from a shrimp cultivation pond in Tamil Nadu (India). Cells were Gram-stain-negative, motile rods. Both strains were positive for catalase and oxidase, hydrolysed Tween 80, and grew chemo-organoheterotrophically with an optimal pH of 6 (range pH 4-9) and at 30 °C (range 25-40 °C). Based on 16S rRNA gene sequence analysis, strains JC109(T) and JC261 were identified as belonging to the genus Alcanivorax with Alcanivorax dieselolei B-5(T) (sequence similarity values of 99.3 and 99.7%, respectively) and Alcanivorax balearicus MACL04(T) (sequence similarity values of 98.8 and 99.2%, respectively) as their closest phylogenetic neighbours. The 16S rRNA gene sequence similarity between strains JC109(T) and JC261 was 99.6%. The level of DNA-DNA relatedness between the two strains was 88%. Strain JC109(T) showed 31 ± 1 and 26 ± 2% DNA-DNA relatedness with A. dieselolei DSM 16502(T) and A. balearicus DSM 23776(T), respectively. The DNA G+C content of strains JC109(T) and JC261 was 54.5 and 53.4 mol%, respectively. Polar lipids of strain JC109(T) included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified aminophospholipids, two unidentified phospholipids and two unidentified lipids. The major fatty acids were C10:0, C12:0, C16:0, C12:0 3-OH, C16:1ω7c, C18:1ω7c and C19:0 cyclo ω8c. Both strains could utilize diesel oil and a variety of xenobiotics as carbon and energy sources. The results of physiological, biochemical, chemotaxonomic and molecular analyses allowed the clear differentiation of strains JC109(T) and JC261 from all other members of the genus Alcanivorax. Strains JC109(T) and JC261 are thus considered to represent a novel species, for which the name Alcanivorax xenomutans sp. nov. is proposed. The type strain is JC109(T) ( = KCTC 23751(T) = NBRC 108843(T)). IUMS.