Oceaniglobus indicus gen. nov., sp. nov., a member of the family Rhodobacteraceae isolated from surface seawater

Abstract

A Gram-stain-negative, non-motile, aerobic and heterotrophic strain, designated 1-19bT, was isolated from surface seawater in the Indian Ocean. The cells were ovoid or coccus (0.8-1.0 µm in diameter) with no flagellum. Activities of catalase and oxidase were positive. Growth was observed at salinity of 0.5-10 (%NaCl, w/v) with an optimum of 3-4, at pH 5-10 with an optimum of 7-8, and at 5-37 °C with an optimum of 28-35 °C. It accumulated poly-β-hydroxybutyrate granules inside the cell. Bacteriochlorophyll a was absent. The respiratory quinone was Q-10 and the dominant fatty acid was summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The major polar lipids comprised phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, an unidentified phospholipid and two unidentified polar lipids. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 1-19bT belonged to the family Rhodobacteraceae and formed a distinct monophyletic clade with 'Oceaniovalibus guishaninsula' JLT2003 and Pontibaca methylaminivorans GRP21T, exhibiting similarities of 94.7 and 92.2 %, respectively. The genomic DNA G+C content was 64.2 mol%. Based on the phenotypic, chemotaxonomic and genotypic data, strain 1-19bT represents a novel species in a new genus of the family Rhodobacteraceae, for which the name Oceaniglobus indicus gen. nov., sp. nov. is proposed, with the type strain 1-19bT (=MCCC 1A11863T=KCTC 52709T).