Flavobacterium commune sp. nov., isolated from freshwater and emended description of Flavobacterium seoulense

A Gram-stain-negative, yellow, facultatively-anaerobic, short, rod-shaped, non-spore-forming bacterium, designated PK15^T, was isolated from freshwater. Growth was observed at 4-40 °C (optimum, 30 °C), pH 6-9 (optimum, 8), and in the presence of 0-0.8 % (w/v) NaCl (optimum, 0.4 %). Strain PK15^T exhibited both catalase and oxidase activities and was able to reduce nitrate. On the basis of 16S rRNA gene sequence similarities, strain PK15^T was shown to belong to the genus Flavobacterium with close similarities to Flavobacterium palustre S44^T (97.9 %) and Flavobacterium seoulense EM1321^T (97.7 %). Menaquinone-6 (MK-6) was the major respiratory quinone, while the G+C content of the genomic DNA was 35.5 (±0.9) mol%. The major polar lipids were phosphatidylethanolamine, three unidentified aminolipids, one unidentified aminophospholipid and three unidentified polar lipids. The predominant cellular fatty acids (≥10 %) were anteiso-C15 : 0 (17.3 %), a summed feature comprising C16 : 1ω7c and/or C16 : 1ω6c (15.1 %) and iso-C15 : 0 (10.0 %). Chemotaxonomic data supported the affiliation of strain PK15^T to the genus Flavobacterium. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain PK15^T from strains of closely related species. It was, therefore, evident that PK15^T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium commune sp. nov. is proposed with strain PK15^T (=KCTC 52562^T=JCM 32115^T) as the type strain. Based on the results of the chemotaxonomic characterization in the present study, an emended description of Flavobacterium seoulense is also proposed.