Polluticaenibacter yanchengensis gen. nov., sp. nov., A Novel Taxon Within the Family Chitinophagaceae Isolated from Activated Sludge

A Gram-stain-negative bacterium, designated strain LY-5 ^T, was isolated from an activated sludge sample collected from a river in Yancheng city, Jiangsu province, China. Cells of strain LY-5 ^T, were strictly aerobic, non-motile and rod-shaped. Growth occurred at 15–37 °C (optimum, 30 °C), at pH 5.0–9.0 (optimum 7.0) and at 0–3% (w/v) NaCl (optimum, 0%). Phylogenetic analysis based on 16S rRNA gene and genome sequences indicated that strain LY-5 ^T formed a distinct phyletic branch within the family Chitinophagaceae, with closest relatives being members of the genera Phnomibacter, Aurantisolimonas, and Chitinophaga, sharing 88.5–90.3% sequence similarity. Moreover, the average amino acid identity (AAI) between strain LY-5 ^T and its closed phylogenetic neighbors was below 70%, indicating it belongs to a novel genus. The predominant cellular fatty acids of LY-5 ^T were iso-C_15:0, iso-C_15:1 G and summed feature 3 (C_16:1 ω7c and/or C_16:1 ω6c), and the only isoprenoid quinone was menaquinone-7 (MK-7). The major polar lipids identified in strain LY-5 ^T comprised phosphatidylethanolamine, two unidentified aminolipids and five unidentified lipids. The genome size of strain LY-5 ^T was 4.8 Mbp with a G + C content of 38.9%. Based on the evidence presented in this study, strain LY-5 ^T represents a novel species of a new genus in the family Chitinophagaceae, for which the name Polluticaenibacter yanchengensis gen. nov., sp. nov. (Type strain LY-5 ^T = CCTCC AB 2023260 ^T = KCTC 102218 ^T) is proposed.