Flavobacterium effusum sp. nov., isolated from a freshwater river.

A yellowish-orange-coloured bacterial strain, PSI-22T, was isolated from a freshwater river in Taiwan. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain PSI-22T belonged to the genus Flavobacterium and showed the highest identity with respect to Flavobacterium dispersum MVW-23T (98.0 %), Flavobacterium tistrianum GB 56.1T (97.1 %), Flavobacterium denitrificans ED5T (97.1 %) and Flavobacterium daemonense THG-DJ7T (97.0 %) and less than 97 % to other members of the genus. Cells of strain PSI-22T were Gram-negative, strictly aerobic, motile by gliding and rod-shaped. Optimal growth occurred at 30 °C, pH 6 and in the presence of 0.5 % NaCl. Strain PSI-22T contained iso-C15 : 0 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) as the predominant fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, one uncharacterized aminophospholipid, one uncharacterized aminophosphoglycolipid, two uncharacterized aminolipids, one uncharacterized phospholipid and one uncharacterized lipid. The major polyamine was homospermidine. The major isoprenoid quinone was MK-6 and the DNA G+C content of the genomic DNA was 41.4 mol%. The DNA-DNA hybridization value for strain PSI-22T with F. dispersum BCRC 80978T, F. tistrianum KCTC 42679T, F. denitrificans DSM 15936T and F. daemonense KACC 17651T was less than 30 %. On the basis of the phylogenetic inference and phenotypic data, strain PSI-22T should be classified as a novel species, for which the name Flavobacterium effusum sp. nov. is proposed. The type strain is PSI-22T (=BCRC 80973T=LMG 29553T=KCTC 52233T).