Flavobacterium keumense sp. nov., isolated from freshwater

A yellow-pigmented, oxidase-positive, catalase-negative, Gram-stain-negative, rod-shaped, aerobic and non-motile bacterial strain designated K3R-10T was isolated from a freshwater source. The strain grew over a temperature range from 4 to 35 °C (optimum, 30 °C), pH range pH 6-8 (optimum, pH 7) and in the presence of 0-0.5 % NaCl (optimum, 0 %). Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain K3R-10T belonged to the genus Flavobacterium and shared close similarities with Flavobacterium succinicans LMG 10402T (97.0 %), Flavobacterium chungangense LMG 26729T (96.4 %), Flavobacterium branchiophilum IFO 15030T (96.4 %) and Flavobacteriumpiscis412R-09T (96.3 %), but formed a distinct phylogenetic line of its own in the phylogenetic trees. The polar lipids consisted of phosphatidylethanolamine, an unidentified aminolipid and three unidentified phospholipids. The DNA G+C content was 35.4 mol%, MK-6 was the major isoprenoid quinone, and homospermidine was the predominant polyamine. The predominant cellular fatty acids were iso-C15 : 0 3-OH, iso-C15 : 0, a summed feature comprising C16 : 1ω7c and/or C16 : 1ω6c and iso-C15 : 1 G. The absence of aminophospholipid, acid production from carbohydrates, DNA G+C content and colony morphology differentiated strain K3R-10T from related species of the genus Flavobacterium. Thus, on the basis of phenotypic, chemotaxonomic and phylogenetic features, strain K3R-10T evidently represents a novel species in the genus Flavobacterium, for which the name Flavobacterium keumense sp. nov. is proposed. The type strain is K3R-10T (=JCM 31220T=KCTC 52563T).