Chitinophaga defluvii sp. nov., a Cyhalofop-Butyl-Degrading Bacterium Isolated from Municipal Sludge.

Abstract

A yellow-colored, Gram-stain-negative, non-motile, and rod-shaped bacterium, designated strain H8^T, was isolated from municipal sludge in Huaibei, China. Strain H8^T was able to grow at 15-37 °C (optimum at 30 °C), pH 6.0-8.0 (optimum at pH 7.0), and 0-2.5% (w/v) NaCl concentration (optimum at 0%). This strain was taxonomically characterized by a polyphasic approach. Based on the 16S rRNA gene sequence analysis, strain H8^T represented to the genus Chitinophaga and shared highest sequence similarities with C. arvensicola DSM 3695^T (97.5%), C. niastensis JS16-4^T (97.3%), C. hostae 2R12^T (97.1%), and C. ginsengisegetis Gsoil 040^T (96.8%). The 16S rRNA gene similarities with other members of the genus Chitinophaga are less than 96.3%. The only respiratory quinone was a menaquinone with seven isoprene units (MK-7); the major polar lipid was phosphatidylethanolamine; and the predominant fatty acids were iso-C_15:0 and C_16:1 ω5c. The genome size of strain H8^T was 7.6 Mb, with 44.3% G + C content. The DNA-DNA relatedness and the average nucleotide identity values among strain H8^T and other relatives were all less than 19.7% and 72.6%, respectively, which fall below the threshold value of 70% and 95% for the strain to be considered as novel. The morphological, physiological, chemotaxonomic, and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbors. Thus, strain H8^T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga defluvii sp. nov. is proposed. The type strain is H8^T (= CCTCC AB 2023228^T = KCTC 102174^T).