A Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, aerobic bacterial strain, designated 16F3Y-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 16F3Y-2T belonged to the family Cytophagaceae in the phylum Bacteroidetes and was most closely related to 'Hymenobacter terrae' DG7A (98.01%), H. soli PB17T (97.26%), H. glaciei VUG-A130T (96.78%), H. antarcticus VUG-A42aaT (96.72%), H. ruber PB156T (96.61%), and H. saemangeumensis GSR0100T (95.77%). The G+C content of the genomic DNA of strain 16F3Y-2T was 62.9 mol%. The isolate contained MK-7 as the predominant respiratory quinone, and summed feature 3 (C16:1 ω7c/C16:1 ω6c; 35.5%), C15:0 iso (16.9%), C16:1 ω5c (10.9%), and C15:0 anteiso (9.9%) as major fatty acids. The major polar lipid was phosphatidylethanolamine. Phenotypic and chemotaxonomic data supported the affiliation of strain 16F3Y-2T with the genus Hymenobacter. However, strain 16F3Y-2T exhibited relatively low levels of DNA-DNA relatedness with 'H. terrae' KCTC 32554 (44.1%) and H. soli KCTC 12607T (24.3%), clearly indicating that the isolate constitutes a new genospecies. Strain 16F3Y-2T could be differentiated from its phylogenetic neighbors on the basis of several phenotypic, genotypic, and chemotaxonomic features. Therefore, strain 16F3Y-2T represents a novel species in the genus Hymenobacter, for which the name Hymenobacter daeguensis sp. nov. is proposed. The type strain is 16F3Y-2T (=KCTC 52537T =JCM 31654T).
Keywords: Bacteroidetes; Hymenobacter; polyphasic taxonomy.