Valorization of banana peel waste through coupled dark fermentation and microbial fuel cells: bioenergy production and life cycle assessment

Agro-food waste, such as banana peel waste, is rich in lignocellulosic biomass and has the potential for sustainable bioenergy recovery. This study established a two-stage process combining dark fermentation (DF) and microbial fuel cells (MFCs) to improve energy yield and evaluate environmental performance. A cellulase-producing Bacillus sp. isolated from cow dung was employed for the biological pretreatment of heat- and acid-treated banana peels to facilitate the efficient hydrolysis of cellulose and hemicellulose. The pretreated biomass facilitated DF, producing 3.1 L/L of biohydrogen, which was modeled well by the Modified Gompertz model. The volatile fatty acid–enriched effluent was then used in single-chamber MFCs, producing maximum power densities of 12.02 W/m³ (banana peel substrate) and 11.18 W/m³ (spent DF media). Furthermore, cradle-to-gate life cycle assessment (LCA) conducted using GaBi software reflected low environmental impact, with a global warming potential of 0.1 kg CO₂-eq and minimal effects in acidification, eutrophication, and ozone depletion categories. This study innovates the valorization of banana peel waste using a DF–MFC system combined with LCA, as it proves to be an effective, scalable, and environmentally friendly waste-to-energy approach.