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

Abstract

Two Gram-negative, non-spore-forming, slightly halophilic gliding bacterial strains, DSW-8T 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 °C and in the presence of 2–3 % (w/v) NaCl. Strains DSW-8T and DSW-9 were characterized chemotaxonomically as containing MK-6 as the predominant menaquinone and iso-C17 : 0 3-OH, iso-C15 : 0 and iso-C15 : 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-8T and DSW-9 fell within the genus Maribacter of the family Flavobacteriaceae. Strains DSW-8T and DSW-9 exhibited no difference in their 16S rRNA gene sequences and possessed a mean DNA–DNA relatedness level of 89 %. Strains DSW-8T 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-8T (=KCTC 12393T=DSM 17201T) 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.