Abstract

A polyphasic taxonomy approach was used to characterize strain YBJ-36T, isolated from a freshwater lake in Taiwan. Phylogenetic analyses, based on 16S rRNA gene sequences and coding sequences of an up-to-date bacterial core gene set (92 protein clusters), indicated that strain YBJ-36T formed a phylogenetic lineage in the genus Mucilaginibacter. 16S rRNA gene sequence similarity indicated that strain YBJ-36T is closely related to species within the genus Mucilaginibacter (93.8–97.8% sequence similarity) and is most similar to Mucilaginibacter fluminis TTM-2T (97.8%), followed by Mucilaginibacter roseus TTM-1T (97.2%). Microbiological analyses demonstrated that strain YBJ-36T is Gram-negative, aerobic, non-motile, rod-shaped, surrounded by a thick capsule, and forms pink-colored colonies. Strain YBJ-36T grew between 20–40°C (optimal range, 35–37°C), pH 5.5–7.0 (optimal pH of 6) and 0–2% NaCl (optimal concentration, 0.5%). The predominant fatty acids of strain YBJ-36T are iso-C15:0 and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), the major polar lipid is phosphatidylethanolamine, the major polyamine is homospermidine, and the major isoprenoid quinone is MK-7. The draft genome is approximately 4.63 Mb in size with a G+C content of 42.8 mol%. Strain YBJ-36T exhibited less than 35% DNA-DNA relatedness with Mucilaginibacter fluminis TTM-2T and Mucilaginibacter roseus TTM-1T. Based on phenotypic and genotypic properties and phylogenetic inference, strain YBJ-36T should be classified in a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter limnophilus sp. nov. is proposed. The type strain is YBJ-36T (= BCRC 81056T = KCTC 52811T = LMG 30058T).

• Keywords: Mucilaginibacter limnophilus sp. nov.; Bacteroidetes; Sphingobacteriia; Sphingobacteriales; Sphingobacteriaceae; polyphasic taxonomy