A Gram-negative, non-motile, rod-shaped, aerobic bacterial strain, designated S2-3-6T, was isolated from soil in Jeollabuk-do province, South Korea, and was characterized taxonomically using a polyphasic approach. According to a comparative 16S rRNA gene sequence analysis, strain S2-3-6T belonged to the family Cytophagaceae and was most closely related to Spirosoma endophyticum EX36T (98.2%), Spirosoma fluviale MSd3T (96.0%), and Spirosoma linguale DSM 74T (95.7%). Strain S2-3-6T contained summed feature 3 (C16:1 ω7c/C16:1 ω6c), C16:1 ω5c, and C16:0 N alcohol as major cellular fatty acids, MK-7 as the predominant respiratory quinone, and phosphatidylethanolamine as the main polar lipid. The DNA G+C content of strain S2-3-6T was 47.8%. Phenotypic and chemotaxonomic data supported the affiliation of strain S2-3-6T to the genus Spirosoma. However, the DNA-DNA relatedness between strain S2-3-6T and Spirosoma endophyticum KACC 17920T was 27%, clearly showing that the isolate constitutes a new genospecies. Strain S2-3-6T could be clearly differentiated from its closest neighbors based on its phenotypic, genotypic, and chemotaxonomic features. Therefore, strain S2-3-6T represents a novel species of the genus Spirosoma, for which the name Spirosoma jeollabukense sp. nov. is proposed. The type strain is S2-3-6T (= KCTC 52725T = JCM 32129T).
Keywords: Bacteroidetes; Polyphasic taxonomy; Spirosoma.