Anaerobic Storage of Erythromycin Fermentation Residue for Sustainable Management and Antibiotic Resistance Mitigation

Ensiling is an effective method for preserving solid organic wastes prior to anaerobic digestion; however, its potential in treating antibiotic fermentation residues remains unclear. This study evaluated the effectiveness of ensiling erythromycin fermentation residue (EFR) with rice straw and a silage additive for erythromycin degradation and reduction of antibiotic resistance genes (ARGs). After 56 days of ensiling, the treated samples showed high fermentation quality; in addition, the erythromycin concentration and ARG abundance decreased by 67 and 78.4%, respectively. Microbial community analysis revealed that the addition of silage additives resulted in a more complex and stable microbial network, suppressing the growth of undesirable microorganisms such as Ruminococcaceae and Clostridiaceae. Compared to traditional methods such as hydrothermal treatment and spray-drying, ensiling achieved cost reductions of 33–61% and significantly reduced CO2, SO2, and NOx emissions. These findings underscore the potential of optimized silage fermentation to enhance the management of antibiotic fermentation wastes, reduce antibiotic resistance risks, and promote environmental sustainability. Future research should aim to refine fermentation processes further and explore the potential use of ensiled EFR for biogas production, providing a comprehensive solution for waste management and renewable energy generation.