• Energy Research

Few studies have focused on the feasibility of microbial fuel cells (MFCs) for removing quinolones antibiotics and their anti-shock capabilities. After 1.5 years of operation, the removal efficiency of 10 mg/L ciprofloxacin in MFCs increased to 99.00% in 88 h. These results are in accordance with the enhanced activity of biofilms and voltage output of MFCs. Additionally, the anti-shock capacities of the biofilms in MFCs were evaluated by treating ofloxacin and enrofloxacin and operating at different temperature and salinity. These MFCs can remove 87.31% and 40.81% of ofloxacin and enrofloxacin in 72 h, respectively. Even exposed to a low temperature of 10 °C or a salinity of 3%, the MFCs can achieve greater than 50% and nearly 80% of ciprofloxacin removal efficiency, respectively. The enrichment of Alcaligenes and Chryseobacterium contributed mostly to the removal of quinolones antibiotics. This study provides scientific evidences for treating wastewater containing quinolones antibiotics using MFCs.

Microbial fuel cell (MFC) is regarded as a promising alternative for enhancing the removal of antibiotic pollutants. In this study, oxytetracycline served as an electron donor in the anode chamber of MFCs, and after continuous operation for 330 days, the efficiency of removal of 10 mg/L oxytetracycline in MFCs increased to 99.00% in 78 h, whereas removal efficiency of only 58.26% was achieved in microbial controls. Compared to microbial controls, higher ATP concentration and persistent electrical stimulation mainly contributed to bioelectrochemical reactions more rapidly to enhance oxytetracycline removal in MFCs. In addition, the analysis of bacterial communities revealed that Eubacterium spp.-as the main functional bacterial genus responsible for oxytetracycline biodegradation-flourished starting from merely 0.00%-91.69% ± 0.27% (mean ± SD) in MFCs. High-throughput quantitative PCR showed that the normalized copy numbers of total antibiotic resistance genes (ARGs) and mobile genetic elements in MFCs were 1.7364 and 0.0065 copies/cell respectively, which were markedly lower than those in the microbial controls. Furthermore, there was no significant correlation between oxytetracycline concentration in the influent and abundance of ARGs in effluent from MFCs. Nevertheless, Tp614, a transposase gene, was found to be enriched in both MFCs and microbial reactors, suggesting that it may be a common challenge for different biological processes for wastewater treatment. This study therefore showed a lower probability of upregulation and transmission of ARGs in MFCs when compared to a traditional anaerobic microbial treatment.