Investigation of the influence of polystyrene microplastics in wastewater on anode biofilm viability and electron transfer in microbial fuel cells performance

Polystyrene microplastics (PSMPs) affect biological processes within microbial fuel cells (MFCs). However, their influence on anode biofilms and MFC performance has yet to be investigated. We studied the impact of PSMPs in wastewater on electroactive biofilm anode formation and voltage production during MFC start-up and operation. The dynamics of anode materials and associated variables were extensively investigated to elucidate their combined effect on MFC performance. Briefly, the intrusion of PSMPs in anolyte electrolytes reduced voltage production, hindered MFC performance, and increased the number of nonelectroactive microorganisms in the biofilm of the anode, which altered electron transport and electrode‒biofilm interactions. The detrimental effects of PSMPs on carbon-based electrodes and carbon cloth (CC) were lower than those of metal-based electrodes and stainless steel (SS). The CC-control configuration demonstrated higher performance, achieving the highest voltage output of 600 mV. It exhibited minimal membrane fouling and sustained long-term voltage production, outperforming both PSMP-affected configurations (CC-PSMP MFC and SS-PSMP MFC). PSMPs applied to wastewater MFC electrodes strengthened initial biofilm structures but deteriorated mature biofilm anodes, reducing the electroactive population and extracellular polymeric substances (EPSs) and leading to decreased MFC performance. Our study reveals the significant influence of PSMPs on MFC performance, emphasizing the need for sustainable solutions to mitigate microplastic pollution. Understanding the complex dynamics among anode materials, PSMP intrusion, and microbial behavior is vital for enhancing MFC efficiency and promoting environmental sustainability. This study does not focus on the specific effects of microplastics on the microbial community structure and metabolic activities in the Microbial Fuel Cell (MFC) system. Instead, our research has primarily demonstrated the impacts of polystyrene microplastics on the overall performance of MFCs.