A bacterial strain designated CAR-16T was isolated from a freshwater lake in Taiwan and characterized using the polyphasic taxonomic approach. Cells were Gram-stain-negative, aerobic, motile by gliding, rod-shaped and formed rose-colored colonies. Optimal growth occurred at 30 °C, pH 7 and with 0 % NaCl. Phylogenetic analyses based on 16S rRNA gene sequences and coding sequences of 92 protein clusters indicated that CAR-16T represented a member of the family Cytophagaceae and formed a phylogenetic lineage in the genus Aquirufa. CAR-16T was most closely related to Aquirufa nivalisilvae 59G-WUEMPELT with a 99.7 % 16S rRNA gene sequence similarity. CAR-16T showed 71.2-79.5 % average nucleotide identity and 17.8-21.7 % digital DNA-DNA hybridization identity with the strains of other species of the genus Aquirufa. The major fatty acids of strain CAR-16T were iso-C15 : 0, iso-C15 : 0 3-OH, C16 : 1ω5c and summed feature 3 (C16 : 1ω7c/C16 : 1ω6c and/or iso-C15 : 0 2-OH). The polar lipid profile consisted of a mixture of phosphatidylethanolamine and several uncharacterized aminophospholipids, phospholipids and lipids. The major isoprenoid quinone was MK-7. The genomic DNA G+C content of CAR-16T was 38.8 mol%. On the basis of phenotypic and genotypic properties and phylogenetic inference, CAR-16T should be classified as representing a novel species of the genus Aquirufa, for which the name Aquirufa rosea sp. nov. is proposed. The type strain is CAR-16T (=BCRC 81153T=LMG 30923T=KCTC 62869T).
Keywords: Aquirufa; freshwater; novel species.