From pollutants to power: Waste-derived materials in microbial fuel cell architecture and substrate utilization

Microbial fuel cells (MFCs) are emerging as a transformative bioelectrochemical technology capable of bridging the gap between circular waste management and sustainable, decentralized power generation. This review critically examines recent advances and emerging trends in waste-to-energy conversion, emphasizing the central role of waste not only as a substrate, but also as a crucial component in the architecture of MFCs. A shift toward waste-derived construction offers a novel pathway to overcome scalability limitations, reduce system costs, and simultaneously mitigate the environmental burden of persistent pollutants. The study highlights the growing importance of waste-derived materials, including both plant-derived biomass residues and non-biogenic waste streams (encompassing mineral, polymeric, and composite materials) for fabricating green electrodes, membranes, and reactors for MFC. Furthermore, the review discusses the advanced fabrication technologies in MFC systems, including 3D printing, nanostructuring, and surface functionalization for integrating waste streams into sustainable electrode and reactor design. A broad spectrum of unconventional substrates is analyzed, covering biodegradable fruit and vegetable waste, and metabolic by-products (human and animal urine, livestock manure, plant root exudates), as well as high-impact anthropogenic streams, specifically hazardous petroleum industry effluents and radioactive waste associated with nuclear power facilities. Waste streams employed as both structural components and substrates demonstrate functional competitiveness with conventional materials, often providing superior power density alongside enhanced pollution remediation. This shift fundamentally reframes MFC engineering by transforming waste from a disposal challenge into a strategic design resource. Within this framework, MFCs emerge as a versatile platform for circular economy development and next-generation sustainable infrastructure.