Chlorpyrifos was one of the most widely used organophosphorus insecticides and the neurotoxicity and genotoxicity of chlorpyrifos to mammals, aquatic organisms and other non-target organisms have caused much public concern. Cupriavidus nantongensis X1^T, a type of strain of the genus Cupriavidus, is capable of efficiently degrading 200 mg/L of chlorpyrifos within 48 h. This is ~100 fold faster than Enterobacter B-14, a well-studied chlorpyrifos-degrading bacterial strain. Strain X1^T can tolerate high concentrations (500 mg/L) of chlorpyrifos over a wide range of temperatures (30–42 °C) and pH values (5–9). RT-qPCR analysis showed that the organophosphorus hydrolase (OpdB) in strain X1^T was an inducible enzyme, and the crude enzyme isolated in vitro could still maintain 75% degradation activity. Strain X1^T can simultaneously degrade chlorpyrifos and its main hydrolysate 3,5,6-trichloro-2-pyridinol. TCP could be further metabolized through stepwise oxidative dechlorination and further opening of the benzene ring to be completely degraded by the tricarboxylic acid cycle. The results provide a potential means for the remediation of chlorpyrifos- contaminated soil and water.

A Gram-stain-negative, aerobic, coccoid to small rod-shaped bacterium, designated X1T, was isolated from sludge collected from the vicinity of pesticide manufacturer in Nantong, Jiangsu Province, China. Based on 16S rRNA gene sequence analysis, strain X1T belonged to the genus Cupriavidus, and was most closely related to C. taiwanensis LMG 19424T (99.1% 16S rRNA gene sequence similarity) and C. alkaliphilus LMG 26294T (98.9%). Strain X1T showed 16S rRNA gene sequence similarities of 97.2%-98.2% with other species of the genus Cupriavidus. The major cellular fatty acids of strain X1T were C16:0, C16:1ω7c and/or iso-C15:0 2-OH (Summed feature 3), C18:1ω7c and C17:0 cyclo, and the major respiratory quinone was ubiquinone Q-8 (94%). The major polar lipids of strain X1T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, aminophospholipid and hydroxyphosphatidylethanolamine. The DNA G+C content was 66.6 mol%. The DNA-DNA relatedness values of strain X1T with five reference strains Cupriavidus taiwanensis LMG 19424T, Cupriavidus alkaliphilus LMG 26294T, Cupriavidus necator LMG 8453T, Cupriavidus gilardii LMG 5886T and Cupriavidus yeoncheonense KCTC 42053T were lower than 70%. The results obtained from phylogenetic analysis, phenotypic characterization and DNA-DNA hybridization indicated that strain X1T should be proposed to represent a novel species of the genus Cupriavidus, for which the name Cupriavidus nantongensis sp. nov. is proposed. The type strain is X1T (=KCTC 42909T=LMG 29218T).