Anthocyanin Boosts Electroactive Biofilms Formation and Regulates Intrinsic Catalytic Activity of Single Cells in Escherichia coli for Sustainable Bio-Electrocatalysis in Microbial Fuel Cells

Microbial fuel cells (MFCs) are a sustainable approach to wastewater treatment and energy recovery. However, their practical utility is often limited by sluggish cathode kinetics. For this technology, developing cost-effective biocatalysts that do not compromise effectiveness is a primary challenge. In this study, we utilized anthocyanin molecularly functionalized Escherichia coli (Cya-WT) to promote the formation of electroactive biofilms and regulate the intrinsic catalytic activity of single cells, thereby enhancing extracellular electron transfer. MFCs incorporating Cya-WT-loaded carbon cloth (CC) biocathodes were configured to simultaneously evaluate power generation and glucose degradation activity. The results indicated that Cya-WT exhibited significantly improved oxygen reduction reaction (ORR) activity, achieving a reduction peak current of 3.61 mA cm−2, compared to 2.02 mA cm−2 for wild-type E. coli (WT). The assembled MFC offers a peak power density of 268 ± 13.4 μW cm−2 and decomposes 17.1 ± 1.15 mM of glucose in 150 h, maintaining a consistent voltage output for 800 h. These results demonstrate that anthocyanin functionalization significantly enhances the electrocatalytic performance and metabolic capabilities of E. coli. This novel catalyst design method offers a new strategy for low-cost, renewable MFC cathode catalysts and shows good promise in MFC biopower generation through the assembly of carbon-based biocathodes.