Sulfide-mediated anammox performance under antibiotics stress, Linking antibiotic resistance genes, functional microbes and nitrogen-sulfur metabolism
Anaerobic ammonium oxidation (Anammox) is a pivotal low-carbon technology for biological nitrogen removal, yet its operational stability is frequently compromised by residual antibiotics in wastewater. This study investigated the combined inhibitory effects of Oxytetracycline (OTC) and Sulfamethoxazole (SMX) on Anammox performance and evaluated the restorative potential of sulfide addition. While high concentrations of OTC and SMX severely suppressed nitrogen removal efficiency, sulfide supplementation successfully restored system activity by establishing a coupled sulfide - autotrophic denitrification and anammox system. Metagenomic analysis revealed that sulfide drove a restructuring of the metabolic network: gene modules related to energy conversion, amino acid synthesis, and cofactor metabolism were significantly upregulated, indicating enhanced interspecies electron transfer and metabolic crosstalk driven by the sulfide - autotrophic denitrification process. Furthermore, sulfide acted as a selective factor promoting the enrichment of the ARGs - containing functional bacterium Brocadia sapporoensis, thereby bolstering the community's resistance profile. This study elucidates the biological mechanisms by which sulfide mitigates antibiotic stress, providing theoretical support and practical strategies for the robust application of anammox in treating antibiotic-laden wastewater.