Aestuariibaculum marinum sp. nov., a marine bacterium isolated from seawater in South Korea

A Gram-negative, non-motile, aerobic bacterium, designated strain IP7^T, was isolated from seawater at the shore of the Incheon Eulwang-ri beach, South Korea. Cells of strain IP7^T are straight or slightly rod-shaped and colonies are round, convex and orange-yellow. Strain IP7^T is flexirubin-negative, mild halophile, catalase-and oxidase-positive, and produces a yellow-orange carotenoid pigment. Growth is optimal at 30°C, pH 7–9, and 2.0–4.0% NaCl (w/v). On the basis of 16S rRNA gene sequence similarity, strain IP7^T is affiliated with genus Aestuariibaculum in the family Flavobacteriaceae, the closest relative being Aestuariibaculum suncheonense SC17^T (98.3% sequence similarity). The DNA G + C content of the novel strain is 37.4 mol%. The only quinone is MK-6 menaquinone. Iso-branched C_15:0, iso-branched C_15:1 G, and iso-branched C_17:0 3-OH are major fatty acids. The major polar lipids are phosphatidylethanolamine, an unidentified aminoglycolipid and two unidentified glycolipids. The DNA-DNA hybridization value of strain IP7^T with Aestuariibaculum suncheonense SC17^T is 28.87%. Based on the collective DNA-DNA hybridization, biochemical, phylogenetic and physiological data, we report a novel species of the genus Aestuariibaculum for which the name Aestuariibaculum marinum sp. nov. is proposed. The type strain is IP7^T (= KCTC 52521^T = JCM 31725^T).