A novel actinobacterium producing biosurfactant, designated OTB305T, was isolated from marine sediment sampled at Otsuchi Bay, Iwate Prefecture, Japan and its taxonomic position was examined using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences exhibited that strain OTB305T was closely related to Streptomyces bohaiensis JCM 19630T (98.8 %) and Streptomyces lonarensis DSM 42084T (98.8 %). The chemotaxonomic characteristics of strain OTB305T corresponded to those of the genus Streptomyces as follows: the diamino acid of the cell-wall peptidoglycan was ll-diaminopimelic acid; whole-cell hydrolysates contained glucose and lacked characteristic major sugars; the predominant isoprenoid quinones were MK-9(H8) and MK-9(H6); the polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and an unidentified phospholipid; the major cellular fatty acids were iso-C16 : 0, C16 : 0 and C16 : 1 ω7c; and the genomic DNA G+C content was 72.83 mol%. However, genomic relatedness analysis based on the average nucleotide identity and some phenotypic characteristics revealed that strain OTB305T was distinguished from closely related Streptomyces species. Therefore, strain OTB305T represents a novel species of the genus Streptomyces, for which the name Streptomyces otsuchiensis sp. nov. is proposed. The type strain is OTB305T (=NBRC 113255T=TBRC 9682T).
Keywords: Streptomyces otsuchiensis; Streptomycetaceae; actinomycetes; biosurfactant; marine sediment.