Bioconversion of sulfamethazine-contaminated chicken manure by black soldier fly larvae: Effects on antibiotic resistance genes and microbial communities

Sulfamethazine (SM2), a widely detected antibiotic in livestock manure, poses environmental and health risks due to its persistence and the proliferation of antibiotic resistance genes (ARGs). In this study, we investigated the degradation of SM2 and the elimination of sulfonamide ARGs (sul1 and sul2) in chicken manure contaminated with varying concentration of SM2 by black soldier fly larvae (BSFL). Quantitative PCR and 16S rRNA gene sequencing were employed to monitor changes in sulfa ARGs and microbial community composition within both the larvae gut and chicken manure. During the 12-day test period, BSFL exhibited strong tolerance to SM2, significantly reducing SM2 concentrations by 80.54%–92.22% across different treatment groups. Concurrently, the abundance of sul1 and sul2 decreased by 79.27% and 79.92% in chicken manure, respectively. Additionally, microbial genera such as Firmicutes (47.18–65%) and Bacillus (9.32–10.25%), which were enriched in both the BSFL gut and chicken manure, were identified as potential contributors to SM2 degradation. These findings provide a promising biotechnological strategy for mitigating antibiotic contamination in livestock manure.