Isolation, identification and characterization of clodinafop-propargyl degrading Sphingopyxis sp. WP68

Abstract:

[Background] Although clodinafop-propargyl (CP) can efficiently control malignant weeds in wheat field, the producing and using of CP cause damage to the environment, and pose a threat to the health of animal and human. [Objective] We isolated an efficient CP-degrading bacterium and studied its degradation characteristics to provide microbial resource for bioremediation of CP pollution. [Methods] The active sludge sample was collected from a pesticide factory. The CP-degrading bacterium was isolated by enrichment cultivation and Luria-Bertani (LB) medium containing CP, and identified by morphological, physiological characteristics and analysis of 16S rRNA gene sequence. Single factor experiments were used to evaluate the degradation characteristics including temperature, pH, inoculum, substrate concentration. The degradation product of CP was identified by UPLC-MS. [Results] An efficient CP-degrading strain WP68 was isolated and identified as Sphingopyxis sp.. Strain WP68 was able to degrade 98.26% of 200 mg/L of CP within 10 h under the condition of 37 °C and pH value of 8.0. The optimal culture conditions for strain WP68 degrading CP were temperature 37 °C, pH 8.0, inoculum 5%, and substrate concentration 200 mg/L. The degradation product of CP was identified as clodinafop acid (CA) by UPLC-MS. Strain WP68 was also capable of degrading cyhalofop-butyl and quizalofop-p-ethyl. [Conclusion] Based on the high efficient degradation ability and high CP-tolerance, Sphingopyxis sp. WP68 has the potential prospect in bioremediation of CP-contaminated soil.

Key words:Clodinafop-propargyl, Sphingopyxis, Isolation and identification, Degradation characteristics