Ketobacter nezhaii sp. nov., a marine bacterium isolated from coastal sediment

A Gram-stain-negative, motile, aerobic and heterotrophic bacterium, designated as GYS_M3H T , was isolated from marine coastal sediment sampled at Xiamen Island. Cells were rod-shaped with one polar flagellum and weakly positive for oxidase and catalase. Growth of the strain occurred at pH 6–9 (optimum, pH 7–8), at 15–37 °C (optimum, 28 °C) and with NaCl concentrations of 1.0–6.0 % (optimum, 2.0 %). It had highest 16S rRNA similarity (97.7 %) to Ketobacter alkanivorans GI5 T , followed by the members of the genus Alcanivorax (lower than 91.2 %). The results of phylogenetic analysis indicated that it belonged to the genus Ketobacter within the family Alcanivoracaceae . In addition, the average nucleotide identity and digital DNA–DNA hybridization values between strain GYS_M3H T and K. alkanivorans GI5 T were 71.4 and 19.7 %, respectively, indicating that strain GYS_M3H T belonged to a novel species. Its genome consisted of 5 318 758 bp, with a genomic DNA G+C content of 50.0 mol%. The respiratory quinone was Q-8 and the dominant fatty acids were identified as iso-C 15 : 0 (25.4 %), C 16 : 1   ω6c/C 16 : 1   ω7 c (14.4 %) and iso-C 13 : 0 (7.2 %). The main polar lipids were phosphatidylethanolamine and phosphatidylglycerol. Therefore, based on phenotypic, chemotaxonomic and phylogenetic results, strain GYS_M3H T represents a novel species within the genus Ketobacter , for which the name Ketobacter nezhaii sp. nov. is proposed, with the type strain GYS_M3H T (=MCCC 1A13808 T =KCTC 72247 T ).