Microbial electrochemical systems for bio-solar energy conversion: recent advances, interfaces, future challenges

Microbial fuel cells (MFCs) are bioelectrochemical structures that rely on microbial activity to transform chemical energy contained in organic substrates into electrical power. Solar-assisted MFCs enhance this concept by combining light-driven processes with microbial catalysis to increase energy harvesting and expand the functional range of traditional MFC-based systems. This review highlights solar-assisted MFCs and related hybrid configurations, including microbial solar cells, Biophotovoltaics systems, MFCs with photobioanodes, microscale MFCs using ultraelectrodes, intimately coupled photobiocatalysis, and dye-sensitized solar cell-based platforms. Recent developments in hybrid bio-solar interface engineering, electrode design, membrane selection, and system integration are compiled in this mini-review. Along with highlighting future research directions towards more sustainable solar-assisted bioelectrochemical energy conversion systems, it also identifies the main challenges limiting performance, stability, and scalability.