Temperatibacter marinus gen. nov., sp. nov., a mesophilic bacterium isolated from surface seawater and description of Temperatibacteraceae fam. nov. in the class Alphaproteobacteria.

A Gram-stain-negative, motile, mesophilic, aerobic, rod-shaped bacterium, strain 5-11(T), was isolated from surface seawater at Muroto city, Kochi prefecture, Japan. The strain exhibited a narrow growth temperature range of 20-30 °C. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain fell within the order Kordiimonadales in the class Alphaproteobacteria and was related most closely to the genus Kordiimonas (up to 91.2 % similarity to the type strains of species of the genus) but branched deeply from species of Kordiimonas. The major fatty acids were iso-C17 : 1ω9c, iso-C15 : 0, and C16 : 1ω7c and/or iso-C15 : 0 2-OH. Ubiquinone-10 (Q-10) was detected as the sole isoprenoid quinone. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and one unidentified aminolipid. Although strains of Kordiimonas have been shown to contain unidentified glycolipids, they were not detected from strain 5-11(T). The DNA G+C content of strain 5-11(T) was 44.3 mol%, a value that was lower than those of strains of Kordiimonas (50-58 mol%) and was relatively low for the members of the class Alphaproteobacteria. On the basis of phenotypic, genotypic and chemotaxonomic data, it is proposed that strain 5-11(T) represents a novel species of a new genus, Temperatibacter marinus gen. nov., sp. nov., within a new family Temperatibacteraceae fam. nov. The type strain of Temperatibacter marinus is 5-11(T) ( = NBRC 110045(T) = LMG 28278(T)).