Enhancing tetracycline removal: Performance and mechanisms of interspecies electron transfer in microbial consortia

With the widespread application of antibiotics in aquaculture, antibiotic contamination of manure has become a serious concern. Interspecies electron transfer between microorganisms plays a crucial role in antibiotic biodegradation. This study investigated the impact and mechanism of electron transfer on tetracycline degradation in microbial electrochemical systems. The results demonstrated that at an initial tetracycline concentration of 5 mg/L, the closed-circuit (CC) group achieved a removal rate exceeding 91.98 % within 4 d, which was 2.71 times higher than that of the open-circuit (OC) group. The electron transfer capacity of the CC group was also significantly greater than that of the OC group. Microbial community analysis identified Serratia, Petrimonas, Pseudochrobactrum, and Sphingobacterium as the key potential tetracycline-degrading genera. Additionally, catalase activity in the CC group was significantly enhanced, reaching up to four times that observed in the OC group. Molecular docking further confirmed the strong affinity between catalase and tetracycline, suggesting that catalase plays a significant role in tetracycline degradation. This study offers both theoretical insights and technical support for enhancing the microbial treatment efficiency of organic pollutants.