Rhodobacter kunshanensis sp. nov., a Novel Bacterium Isolated from Activated Sludge

Strain HX-7-19^T was isolated from the activated sludge collected from an abandoned herbicide manufacturing plant in Kunshan, China. Cells were Gram-reaction-negative, rod-shaped, and non-motile. The phylogenetic analysis based on 16S rRNA gene indicated that strain HX-7-19^T formed a clade with Rhodobacter blasticus CGMCC 1.3365^T (96.3% sequence similarity). The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain HX-7-19^T and R. blasticus CGMCC 1.3365^T were 76.2% and 20.3%, respectively. The genomic DNA G + C content of strain HX-7-19^T was 65.9%. The major fatty acids (> 10% of the total fatty acids) were C_18:1 ω7c and C_18:1 ω7c 11-methyl. The major respiratory quinone was quinone Q-10. The major polar lipid profile consists of phosphatidylglycerol (PG), diphosphatidyl-glycerol (DPG), phosphatidylethanolamine (PE), and phosphatidylcholine (PC). Photosynthesis pigments bacteriochlorophyll a and carotenoids were formed and photosynthesis genes pufL and pufM were detected. On the basis of phenotypic and phylogenetic evidences, strain HX-7-19^T is considered as a novel species in the genus Rhodobacter, for which the name Rhodobacter kunshanensis sp. nov. is proposed. The type strain is HX-7-19^T (= KCTC 72471^T = CCTCC AB 2020148^T).