Antarctobacter jejuensis sp. nov., isolated from seawater in Jeju, Korea.

A novel bacterium, designated strain 13-2-B6(T), was isolated from seawater adjacent to Songak Mountain on Jeju Island, South Korea. The novel strain was observed to be Gram-negative, aerobic, rod-shaped and motile with a single polar flagellum. On the basis of 16S rRNA gene sequence similarity, strain 13-2-B6(T) was determined to be phylogenetically closely related to the type strain of Antarctobacter heliothermus, currently the sole species of the genus Antarctobacter (family Rhodobacteraceae). Sequence similarity between the 16S rRNA genes of strain 13-2-B6(T) and A. heliothermus EL-219(T) is 96.9 %. Strain 13-2-B6(T) was found to grow optimally at 25-30 °C, pH 7.0-8.0 and 3 % (w/v) NaCl. The predominant isoprenoid quinone in strain 13-2-B6(T) was identified as ubiquinone Q-10 and the major fatty acids were identified as C18:1 ω7c and/or C18:1 ω6c. Phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, two unknown aminolipids, two unknown phospholipids, an unknown glycolipid and an unknown lipid were found to be components of the polar lipid profile. The G + C content of strain 13-2-B6(T) was determined to be 62 mol %. On the basis of its phenotypic, chemotaxonomic and phylogenetic distinctiveness, strain 13-2-B6(T) is considered to represent a novel species of the genus Antarctobacter, for which the name Antarctobacter jejuensis sp. nov. is proposed. The type strain is 13-2-B6(T) (=KCTC 42009(T) =JCM 19898(T)).