Construction and functional characterization of a synthetic consortium for synergistic degradation of dimethachlon

The residual dicarboximide fungicide dimethachlon and its primary metabolite 3,5-dichloroaniline entail significant health and ecological risks. Microbial degradation effectively mitigates associated environmental risks. The microbial degradation of organic contaminants is a complex process, typically facilitated by microbial consortia rather than individual species. However, research on the biodegradation of dimethachlon by synergistic microbial consortia is limited. In this study, an enriched bacterial consortium designated as JHJ-2 capable of degrading dimethachlon was obtained. A synthetic consortium was constructed, comprising Bosea sp. S6, which transforms dimethachlon to 3,5-dichloroaniline, and Pseudomonas sp. KH-1, which degrades 3,5-dichloroaniline; both strains were isolated from the enriched consortium JHJ-2 and synergistically degrade dimethachlon. Toxicity assays using the zebrafish showed that dimethachlon is converted into non-toxic products by the synthetic consortium (strains S6 and KH-1). Bioaugmentation with the synthetic consortium led to the complete removal of dimethachlon and its highly toxic metabolite 3,5-dichloroaniline from contaminated soil. In addition, 16 bins were successfully recovered by metagenomic binning, including bin 12 (Bosea sp.) and bin 15 (Pseudomonas sp.), and several potential degradation enzymes were hypothesized in the genomes of bins 12 and 15. Overall, the developed synthetic consortium exhibits significant potential for the enhanced bioremediation and detoxification of dimethachlon-contaminated sites.