Role of microalgae in fuel cell based wastewater treatment and bioelectricity generation

The accelerating global demand for sustainable energy and advanced wastewater treatment is driving the development of integrated bioelectrochemical platforms. Microalgae-assisted microbial fuel cells (MAFCs) have emerged as an innovative technology that couples renewable electricity generation with high-efficiency pollutant remediation, aligning closely with circular bioeconomy principles. In MAFCs, microalgae act as photosynthetic bioengineers, supplying in situ oxygen for cathodic reactions, fixing carbon dioxide, assimilating nutrients and contaminants from wastewater, thereby reducing external energy inputs and generating value-added biomass. This review delivers a comprehensive, forward-looking analysis of MAFC systems, highlighting electrode and membrane design, along with the unique physiological traits of microalgae that enhance power density, improve treatment performance, and support long-term system sustainability. It critically examines the influence of operational parameters and diverse reactor configurations while addressing persistent barriers such as light delivery, strain optimization and scalability. Novel strategies, including advanced electrode surface engineering, reactor integration with complementary processes, plus biomass valorization, are presented to strengthen both energy recovery as well as wastewater resource recovery. Finally, the environmental and techno-economic feasibility of MAFCs is evaluated through circular bioeconomy frameworks, underscoring their transformative potential to unify wastewater treatment, renewable energy generation, sustainable development.