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, was isolated from an activated sludge sample collected from a river in Yancheng city, Jiangsu province, China. Cells of strain LY-5, 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 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 and its closed phylogenetic neighbors was below 70%, indicating it belongs to a novel genus. The predominant cellular fatty acids of LY-5 were iso-C, iso-C G and summed feature 3 (C ω7c and/or C ω6c), and the only isoprenoid quinone was menaquinone-7 (MK-7). The major polar lipids identified in strain LY-5 comprised phosphatidylethanolamine, two unidentified aminolipids and five unidentified lipids. The genome size of strain LY-5 was 4.8 Mbp with a G + C content of 38.9%. Based on the evidence presented in this study, strain LY-5 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 = CCTCC AB 2023260 = KCTC 102218) is proposed.