Marinobacterium mangrovicola sp. nov., a marine nitrogen-fixing bacterium isolated from mangrove roots of Rhizophora mangle

A nitrogen-fixing marine bacterium, designated strain Gal22(T), was isolated from mangrove roots of Rhizophora mangle. Cells were Gram-stain-negative rods, motile with a single polar flagellum. Growth was observed at 4-42 °C, pH 5.5 to 10 and with 0-18 % (w/v) NaCl. Strain Gal22(T) was positive for catalase and oxidase. Q-8 was the predominant lipoquinone. The DNA G+C content was 57.0 mol%. Based on phylogenetic analysis of 16S rRNA gene, strain Gal22(T) belongs to the genus Marinobacterium. The closely related strains were shown to be Marinobacterium lutimaris DSM 22012(T) and Marinobacterium litorale IMCC1877(T) with 99 % and 96 % 16S rRNA gene sequence similarity, respectively. DNA-DNA relatedness analysis indicated that strain Gal22(T) was different from M. lutimaris DSM 22012(T). On the basis of genotypic, morphological and biochemical characteristics, a novel species, Marinobacterium mangrovicola sp. nov. (type strain, Gal22(T) = DSM 27697(T) = CIP 110653(T)), is proposed.