Flavobacterium hydrophilum sp. Nov. and flavobacterium cheongpyeongense sp. nov., isolated from freshwater

Two Gram-stain-negative, non-motile, yellow-pigmented bacterial strains, designated IMCC34758 ^T and IMCC34759 ^T , were isolated from freshwater. Phylogenetic analysis based on 16S rRNA gene sequences showed that the two strains formed a distinct clade within the genus Flavobacterium and they shared 97.9 % sequence similarity. The average nucleotide identity (ANI) and digital DNA–DNA hybridization values (dDDH) between the two strains were 85.5 and 30.2 %, respectively, indicating that they are separate species. The two strains showed 98.5 % 16S rRNA gene sequence similarities, 80.6–81.3 % of ANI and 24.7–25.1 % of dDDH values to closely related species of the genus Flavobacterium, indicating that the two strains each represent novel Flavobacterium species. The respiratory quinone detected in both strains was menaquinone-6 (MK-6). The major polar lipids of the two strains were phosphatidylethanolamine, an unidentified aminolipid, an unidentified aminophospholipid and an unidentified polar lipid. The DNA G+C contents of strains IMCC34758 ^T and IMCC34759 ^T were 34.0 and 34.1 mol%, respectively. The major fatty acids of the two strains were very similar to each other, comprising iso-C _{15: 0} , iso-C _{15: 1} G, anteiso-C _{15: 0} and summed feature 3 (C _{16: 1} ω6c and/or C _{16: 1} ω7c). Phenotypic characteristics including enzyme activities and carbon source utilization differentiated the two strains from other Flavobacterium species. Based on these results, strains IMCC34758 ^T and IMCC34759 ^T were considered to represent novel species in the genus Flavobacterium, for which the names Flavobacterium hydrophilum (IMCC34758 ^T =KACC 19591 ^T =NBRC 113423 ^T ) and Flavobacterium cheongpyeongense (IMCC34759 ^T =KACC 19592 ^T =NBRC 113424 ^T ) are proposed, respectively.