Hymenobacter knuensis sp. nov., Isolated From River Water.

A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterial strain, designated 16F7C-2T, was isolated from the Han River, South Korea, and was characterized taxonomically using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain 16F7C-2T belonged to the family Cytophagaceae in the phylum Bacteroidetes and was most closely related to Hymenobacter algoricola VUG-A23aT (98.3%) and Hymenobacter fastidiosus VUG-A124T (97.7%). The G + C content of the genomic DNA of strain 16F7C-2T was 63.4 mol%. The detection of menaquinone MK-7 as the predominant respiratory quinone; a fatty acid profile with summed feature 3 (C16:1 ω7c/C16:1 ω6c; 19.5%), summed feature 4 (C17:1 iso I/C17:1 anteiso B; 15.9%), C15:0 iso (12.6%), C16:1 ω5c (10.5%), and C15:0 anteiso (10.4%) as the major components; and a polar lipid profile with phosphatidylethanolamine as the major component also supported the affiliation of strain 16F7C-2T to the genus Hymenobacter. The DNA-DNA relatedness between strain 16F7C-2T and H. algoricola JCM 17214T and H. fastidiosus JCM17224T were 45.2 ± 5.8 and 40.3 ± 2.9%, respectively, clearly showing that the isolate constitutes a new genospecies. Strain 16F7C-2T could be clearly differentiated from its closest neighbors on the basis of its phenotypic, genotypic, and chemotaxonomic features. Therefore, strain 16F7C-2T represents a novel species of the genus Hymenobacter, for which the name Hymenobacter knuensis sp. nov. is proposed. The type strain is 16F7C-2T (=KCTC 52538T = JCM 31814T).