Two Gram-stain-negative, yellow-pigmented and strictly aerobic bacteria, designated strains SE-s27T and SE-s28T, were isolated from forest soil. Both strains were non-motile rods that were catalase-positive and oxidase-negative and grew optimally at 25-30 °C, pH 8.0 and with 0 % (w/v) NaCl. Strain SE-s28T produced flexirubin-type pigments, but strain SE-s27T did not produce them. Both strains contained menaquinone-6 as the sole respiratory quinone and phosphatidylethanolamine as a major polar lipid. As the major cellular fatty acids (>10 %), SE-s27T contained iso-C15 : 1 and iso-C15 : 1G, whereas SE-s28T contained iso-C15 : 0 and summed feature 3 comprising C16 : 1ω7c and/or C16 : 1ω6c and/or iso-C15 : 0 2-OH. The DNA G+C contents of strains SE-s27T and SE-s28T were 33.1 and 44.3 mol%, respectively. The results of phylogenetic analysis based on 16S rRNA gene sequences revealed that SE-s27T and SE-s28T formed respective distinct phylogenetic lineages within the genus Flavobacterium. Strains SE-s27T and SE-s28T were most closely related to Flavobacterium macrobrachii an-8T and Flavobacterium piscinae ICH-30T with 98.0 and 94.5 % 16S rRNA gene sequence similarities, respectively. In conclusion, strains SE-s27T and SE-s28T represent novel species of the genus Flavobacterium, for which the names Flavobacterium solisilvae sp. nov. and Flavobacterium silvaticum sp. nov. are proposed. The type strains of F. solisilvae and F. silvaticum are SE-s27T (=KACC 18802T=JCM 31544T) and SE-s28T (=KACC 18803T=JCM 31545T), respectively.
Keywords: Flavobacterium silvaticum; Flavobacterium solisilvae; forest soil; new taxa; taxonomy.