The metabolic pathway of clodinafop-propargyl degradation by consortium WP and its bacterial diversity analysis

Abstract

Clodinafop-propargyl (CP) is a widely used post-emergence aryloxyphenoxy propionate (AOPP) herbicide and causes serious environmental problems. The elimination of CP from the environment is urgently required, but there are few reports on microbial degradation of CP. In this study, a bacterial consortium WP was enriched from the activated sludge of CP containment, which could completely degrade 50 mg L−1 of CP within 7 days. UPLC-MS analysis showed that the main intermediate metabolites of CP degradation were clodinafop acid (CA), 4-(5-chloro-3-fluoro-2-pyridyloxy) phenol, and 5-chloro-3-fluoropyridin-2-ol. And the metabolic pathway of CP degradation by consortium WP has been proposed. High-throughput sequencing revealed that the consortium WP had rich bacterial diversity, including 4 phyla, 14 classes, and 148 genera. Ten bacteria capable of converting CP to CA were isolated from the consortium WP using LB medium containing CP, and the strain Pseudoxanthomonas sp. WP66 had the strongest conversion ability, which could utilize CP as the sole source for growth and degrade 91.20% of 100 mg L−1 CP within 15 h. This study presented the main degradation pathways of CP by microorganisms, and provided resource of bacterial strain for the removal of CP from the environment.