Algae-driven bioelectrochemical systems: Recent advances, applications, and prospects

Bioelectrochemical systems (BESs) are sustainable biotechnologies that have garnered global interest in recent decades. Since their inception, these systems have evolved through various configurations and modifications to enhance performance, prominently featuring microbial fuel cells (MFCs). Researchers are addressing the scaling challenges of MFCs with studies on algae-assisted MFCs (algae-MFCs), which simultaneously generate bioelectricity and treat wastewater cost-effectively. Algae-MFCs are carbon-neutral and photosynthesize to sequester CO₂ while producing oxygen (O₂) and biomass. O₂ serves as an effective electron acceptor, and biomass is a biofuel feedstock, making the process economical and eco-friendly. This review highlights recent advances in algae-based MFCs, focusing on bioelectricity generation (up to 26,680 mW/m²) and biofuel outputs (200 mL/L/h of biohydrogen, 286 mL/g/VS of biomethane, 3.37 g/L of biobutanol, 73 g/L of bioethanol, and 121,104 kg/ha∙year of biodiesel), along with innovations in biokerosene (bio-jet) technology. The impacts of reactor components and configurations on algae-MFC performance, scaling strategies, real-time applications, and computational studies of algae-based BESs are also examined. Furthermore, this review assesses the technoeconomic viability, challenges, and future prospects of this technology. Overall, the findings suggest that algae-MFCs effectively remove contaminants from wastewater and increase power generation while also outlining directions for future advancements.