Advances in photobioelectrochemistry: From interface engineering to integrated biohybrid systems for CO₂ conversion, waste valorization, and solar-driven resource recovery.

Photobioelectrochemistry couples light-harvesting and electrochemical materials with biological catalysts to convert solar energy into fuels, chemicals, and recoverable resources. A central premise is that photobioelectrochemical performance depends on how biological catalysts, photoactive materials, interfacial charge-transfer pathways, and operating environments are coupled, rather than on any component in isolation. The biotic-abiotic interface and reactor context provide the basis for comparing recent advances in biological catalysts, engineered photoactive interfaces, and reactor configurations. These advances are discussed with particular focus on solar fuel generation, CO₂ conversion and upgrading, and the use of waste and wastewater streams for value recovery, nutrient capture, bioproduction, and bioremediation. Across these systems, the review examines how interface design, electrode architecture, and reactor conditions control the delivery of photogenerated charge to biological catalysts, thereby influencing activity, selectivity, and stability. By linking interfacial charge transfer with biological function and reactor-level constraints, this review aims to identify design considerations that can support the transition of photobioelectrochemical systems from isolated demonstrations to practical sustainable biotechnology applications.