Effects of chloramphenicol on denitrification in single-chamber microbial fuel cell: Comprehensive performance and bacterial community structure

Abstract

This study investigated the effects of chloramphenicol (CAP) pressure on denitrification performance, electricity generation performance, the expression of antibiotic resistance genes (ARGs), and microbial community structure in microbial fuel cell (MFC) system and plain anaerobic reactor. The results showed that the MFC had better denitrification and CAP degradation performances under CAP stress. CAP at a concentration of 10 mg L–1 significantly inhibited denitrification in both systems. However, at 20 mg L–1 CAP, the denitrification capacity recovered and seemed unaffected, especially in MFC system, due to the increased abundance of Rhodocyclaceae electron transfer dominant bacteria, pseudomonas denitrifying bacteria, and Burkholderiaceae carrying both ARGs and denitrifying genes. In addition, the qPCR results showed that the MFC could promote the horizontal transfer of resistance genes, making MFC superior under CAP pressure. The high-throughput sequencing results showed that bacterial communities significantly changed under different CAP concentrations, especially the dominant bacteria, such as Geobacter, Pannonibacter, Pseudomonas, Rhodocyclaceae and Burkholderiaceae. In conclusion, this study reveals MFC is a more promising method and provides theoretical guidance for the treatment of practical wastewater by MFCs.