Marinobacter excellens sp. nov., isolated from sediments of the Sea of Japan

Five strains of halophilic, Gram-negative marine bacteria (KMM 3809(T), KMM 3814, KMM 3815, KMM 3817 and KMM 3818) were isolated from sediments collected from Chazhma Bay, Sea of Japan. Phylogenetic 16S rRNA gene sequence-based analysis placed these bacteria in a clade within the genus Marinobacter in the gamma-Proteobacteria. KMM 3809(T) showed highest 16S rRNA gene sequence similarity of 97.3 % to Marinobacter litoralis and 96.9 % to Marinobacter hydrocarbonoclasticus and Marinobacter aquaeolei. DNA-DNA hybridization between the five isolates was at the conspecific level (94-96 %) and that among the closest phylogenetic neighbours ranged from 45.0 to 62.5 %. The new organisms were susceptible to polymyxin. Predominant fatty acids were C(16 : 0), C(16 : 1)omega9c, C(16 : 1)omega7c and C(18 : 1)omega9c. Phylogenetic evidence, along with phenotypic and genotypic characteristics, showed that the bacteria constituted a novel species of the genus Marinobacter. The name Marinobacter excellens sp. nov. is proposed for this species, with the type strain KMM 3809(T) (=CIP 107686(T)).