Flavobacterium rivulicola sp. nov., Isolated from a Freshwater Stream.

A Gram-strain-negative, aerobic, yellow-colored, non-motile, and rod-shaped bacterial strain, designated IMCC34852, was isolated from a freshwater stream in the Republic of Korea. Cellular growth occurred at 10-37 °C, pH 6.0-9.0, and with 0-0.5% (w/v) NaCl. The 16S rRNA gene sequence analysis showed that strain IMCC34852 belonged to the genus Flavobacterium and that the strain was most closely related to F. cheonhonense ARSA-15 (97.6%), F. buctense T7 (96.7%), F. silvisoli RD-2-33 (96.1%), and F. paronense KNUS1 (96.1%). The whole-genome sequence of strain IMCC34852 was 3.2 Mbp in size, with a DNA G + C content 37.3%. The average nucleotide identities (ANI) and digital DNA-DNA hybridization (dDDH) values between strain IMCC34852 and its related species were all below 79.8% and 22.7%, respectively, which are significantly lower than the thresholds of 95% for ANI and 70% for DDH for species delineation. The major respiratory quinone of strain IMCC34852 was menaquinone-6 (MK-6) and the predominant cellular fatty acids were iso-C (32.6%), iso-C (11.7%), iso-C G (10.3%), and iso-C (6.7%). The major polar lipids of the strain were phosphatidylethanolamine, two unidentified aminolipids and six unidentified lipids. Based on these results, it was concluded that strain IMCC34852 represents a novel species in the genus Flavobacterium, for which the name Flavobacterium rivulicola sp. nov is proposed. The type strain of the proposed novel species is IMCC34852 (= KACC 23133 = KCTC 82066 = NBRC 114419).