A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterium, designated 15J8-5T, was isolated from beach soil on Jeju Island, Republic of Korea. The isolate grew at 10-37 °C (optimal 25 °C), pH 6-8 (optimal pH 7) and in the presence of 0-1 % (w/v) NaCl. The results of comparative 16S rRNA gene sequence analysis indicated that strain 15J8-5T represented a member of the family Cytophagaceae, phylum Bacteroidetes and was most closely related to Spirosoma knui 15J8-12T (93.1 % similarity), Spirosoma spitsbergense SPM-9T (93.1 %) and Spirosoma endophyticum EX36T (93.1 %). The G+C content of the genomic DNA of the novel strain was 48.0 mol%. The isolate contained menaquinone MK-7 as the predominant respiratory quinone, phosphatidylethanolamine as the major polar lipid, and summed feature 3 (C16 : 1ω7c/C16 : 1ω6c; 32.8 %), C16 : 1ω5c (24.8 %) and C16 : 0 (11.7 %) as the major fatty acids, which supported the affiliation of strain 15J8-5T to the genus Spirosoma. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain 15J8-5T from members of the genus Spirosoma. Based on its phenotypic properties and phylogenetic distinctiveness, strain 15J8-5T represents a novel species of the genus Spirosoma, for which the name Spirosomakoreense sp. nov. is proposed. The type strain is 15J8-5T (=KCTC 52027T=JCM 31992T).
Keywords: Bacteroidetes; Spirosoma; polyphasic taxonomy.