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 Flavobacteriumspecies. 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-C15 : 0, iso-C15 : 1 G, anteiso-C15 : 0 and summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c). Phenotypic characteristics including enzyme activities and carbon source utilization differentiated the two strains from other Flavobacteriumspecies. 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.