Enhanced Co-degradation of chloramphenicol and polyvinyl chloride in water by bioelectrochemical systems

In response to the escalating issue of antibiotic-microplastic co-contamination in aquatic environments, this study first investigated the performance and underlying mechanisms of microbial fuel cells (MFCs) in treating such pollutants in wastewater. The degradation of chloramphenicol (CAP), polyvinyl chloride (PVC), their combined contamination, and the combined system supplemented with the quorum sensing signal molecule 3OC8-HSL were evaluated. The results demonstrated that PVC co-occurrence enhanced the degradation of both pollutants (CAP degradation rate constant increased by 31.65 % and PVC weight loss increased by 93.27 %). The addition of 3OC8-HSL further facilitated CAP degradation (degradation rate constant increased by 78.14 %) and electricity generation of the MFC (maximum power density enhanced by 81.05 %). PVC primarily promoted pollutant removal by adsorbing CAP, thereby alleviating its acute toxicity, while increasing the abundance of the dual-functional degradation gene adhP in the anode biofilm to enhance the CAP and PVC degradation efficiencies. The addition of 3OC8-HSL increased the biomass and activity of the anode biofilm, selectively enriched the electroactive bacteria for both CAP and PVC degradation, with Achromobacter sp. M3 and Klebsiella sp. X11 identified as the key bacteria which harbor complete sets of CAP and PVC degradation genes and secret riboflavin. Furthermore, 3OC8-HSL reinforced multi-pathway CAP degradation and bioelectricity generation by enriching key genes involved in acetylation (ACAT, atoB), dechlorination (E3.8.1.2, dehH), deamidation (E3.5.1.4, amiE), ring cleavage (pcaC), β-oxidation (Paaf, echA, paaH, hbd, fadB, mmgB), and riboflavin synthesis (rutF, ushA, ribE). This study offers a novel strategy for the bioremediation of antibiotic-microplastic co-contamination in aquatic environments.