A novel bacterial strain AHQ-46T was isolated from a freshwater lake in Taiwan. The strain was Gram-stain-negative, strictly aerobic, motile by gliding, rod-shaped and formed translucent yellow colonies. Optimal growth occurred at 20-25 �XC, pH 7.0, and in the absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain AHQ-46T belonged to the genus Flavobacterium and was most closely related to Flavobacterium verecundum TTM-46T with a sequence similarity of 95.8 %. Strain AHQ-46T contained iso-C15 : 1 G, iso-C15 : 0, summed feature 3 (C16 : 1�s6c and/or C16 : 1�s7c) and iso-C17 : 0 3-OH as the predominant fatty acids. The polar lipid profile consisted of phosphatidylethanolamine and several uncharacterized aminophospholipids and phospholipids. The major polyamine was homospermidine. The major isoprenoid quinone was MK-6. The DNA G+C content of the genomic DNA was 32.1 mol%. Differential phenotypic properties, together with the phylogenetic inference, demonstrate that strain AHQ-46T should be classified as a representative of a novel species of the genus Flavobacterium, for which the name Flavobacterium lacunae sp. nov. is proposed. The type strain is AHQ-46T (=BCRC 80889T=LMG 28710T).