Maribacter dokdonensis sp. nov., isolated from sea water off a Korean island, Dokdo

Two Gram-negative, non-spore-forming, slightly halophilic gliding bacterial strains, DSW-8(T) and DSW-9, were isolated from sea water off a Korean island, Dokdo, of the East Sea, Korea, and their taxonomic position was investigated by a polyphasic study. The two strains grew optimally at 30 degrees C and in the presence of 2-3% (w/v) NaCl. Strains DSW-8(T) and DSW-9 were characterized chemotaxonomically as containing MK-6 as the predominant menaquinone and iso-C(17:0) 3-OH, iso-C(15:0) and iso-C(15:1) as the major fatty acids. Major polar lipids were phosphatidylethanolamine, two unidentified phospholipids, an unidentified glycolipid and an amino group-containing lipid that was ninhydrin-positive. Their DNA G+C contents were 36.1 and 35.9 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains DSW-8(T) and DSW-9 fell within the genus Maribacter of the family Flavobacteriaceae. Strains DSW-8(T) and DSW-9 exhibited no difference in their 16S rRNA gene sequences and possessed a mean DNA-DNA relatedness level of 89%. Strains DSW-8(T) and DSW-9 exhibited 16S rRNA gene sequence similarity levels of 96.9-98.0% to the type strains of the four recognized Maribacter species, but their low level of DNA-DNA relatedness with these species demonstrated that they constitute a distinct Maribacter species. On the basis of phenotypic and phylogenetic data and genetic distinctiveness, strains DSW-8(T) (=KCTC 12393(T)=DSM 17201(T)) and DSW-9 were classified in the genus Maribacter as members of a novel species, for which the name Maribacter dokdonensis sp. nov. is proposed.