Abstract

A Gram-stain-negative, non-motile, non-spore-forming, rodshaped, aerobic bacterium, designated 15J9-6T, was isolated from beach soil on Jeju Island, South Korea. Strain 15J9-6T, grew at 10–30°C (optimum growth at 25°C) and pH 7–8 (optimum growth at pH 7) on R2A, NA, and TSA agar. Phylogenetically, the strain was closely related to members of the genus Spirosoma (92.3–90.1% 16S rRNA gene sequence similarities) and showed highest sequence similarity to Spirosoma panaciterrae DSM 21099T (92.3%). The G+C content of the genomic DNA of strain 15J9-6T was 45.7 mol%. The strain contained phosphatidylethanolamine, two unidentified aminophospholipids, an unidentified phospholipid, and an unidentified lipid as the major polar lipids; menaquinone MK-7 as the predominant respiratory quinone and summed feature 3 (C16:1 ω6c/C16:1 ω7c; 30.1%), C16:1 ω5c (23.1%), iso C15:0 (13.3%), and C16:0 (8.4%) as the major fatty acids which supported the affiliation of strain 15J9-6T to the genus Spirosoma. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain 15J9-6T from recognized Spirosoma species. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain 15J9-6T represents a novel species of the genus Spirosoma, for which the name Spirosoma daeguensis sp. nov. is proposed. The type strain is 15J9-6T (=KCTC 52036T =JCM 31995T)

• Keywords: Spirosoma;Bacteroidetes;polyphasic taxonomy