Removal of prothioconazole using screened microorganisms and identification of biodegradation products via UPLC-QqTOF-MS

Degradation of the prothioconazole by three strains of microorganisms isolated from activated sludge obtained from a pesticide factory was assessed, and an ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QqTOF-MS) method for the determination of prothioconazole and its metabolites was established. The optimal conditions for the degradation of prothioconazole were determined by single factor optimization experiments. A degradation rate of 93.32% is achieved when the prothioconazole is co-cultured with the strain W313 at a cultivation time of 60 h, a cultivation temperature of 30 °C, a pH of 6.33, a prothioconazole concentration of 50 mg L−1, a microorganism volume of 10%, and a dextrose volume of 4%. The three effective microorganism strains were identified by morphological and molecular biology to be Candida tropicalis, Enterobacter cloacae, and Pseudomonas aeruginosa. UPLC-QqTOF-MS analysis allowed the identification of 62 different prothioconazole degradation products produced by the strain cultures, with prothioconazole-desthio, prothioconazole-dechloropropyl, and oxidizing prothioconazole being the main products. In addition, degradation products from different strains and conditions were compared. The results of scatter plot (S-Plot) analysis indicated that C9H7NO, C10H17N7, and C12H13ClN2O were only detected in the products incubated with Enterobacter cloacae. Thus, this study demonstrates that Enterobacter cloacae and Pseudomonas aeruginosa possesses high potential for bioremediation of prothioconazole-contaminated environments.