Removal of Sulfachloropyridazine and Associated Antibiotic Resistance Genes During Anaerobic Digestion for Lactic Acid Production

Highlights Anaerobic digestion for lactic acid process can effectively remove sulfachloropyridazine. Threshold concentration for complete removal of sulfachloropyridazine is 50 mg/kg·TS. Sulfachloropyridazine did not significantly affect lactic acid production. IntI1, sul1, sul2, sul3, sulA, and tnpA were reduced by 28%–98%. IntI1 was significantly correlated with sul1, sul2, and sul3. ABSTRACT. Livestock manure containing sulfachloropyridazine (SCP) and associated antibiotic resistance genes (ARGs) requires effective treatment to mitigate environmental risks. Although anaerobic digestion (AD) for lactic acid (LA) production is valuable, its efficacy in reducing SCP and ARGs remains unclear. This study investigated the removal of SCP and ARGs during AD for LA process. Results showed that AD for LA process is effective in removing SCP and ARGs. Complete SCP degradation was achieved at a threshold concentration of 50 mg/kg·TS. Significant reductions were observed in ARGs, including intI1 (98%), sul1 (97%), sul2 (86%), sul3 (90%), sulA (28%), and tnpA (78%). IntI1 was significantly correlated with sul1, sul2, and sul3. SCP had not significantly affected LA production, with the maximum concentration of LA reaching 57,307±4,003 mg/L. This study can provide new knowledge about the AD for LA process that can be used to reduce the negative effects of antibiotics and ARGs contained in livestock manure. Keywords: Anaerobic digestion, Antibiotic resistance genes, Lactic acid, Removal, Sulfachloropyridazine.