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 degrees C (optimum, 30 degrees 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-C-15:0 (17.3 %), a summed feature comprising C-16:1 omega 7c and/or C-16:1 omega 6c (15.1 %) and iso-C-15:0 (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.