Bioenergy from agriculture: converting rice waste into green electricity

The improper management of rice waste, including straw and husks, not only contributes to environmental pollution — releasing CO₂, N₂O, and SO₂ through burning—but also restricts energy access in rural communities. In Peru, where 15.5% of households remain without electricity, this issue presents a substantial obstacle to socioeconomic development. This study examines the potential of rice straw fermentate as a substrate in single-chamber microbial fuel cells (MFCs), seeking to generate bioelectricity while addressing agricultural waste concerns. Rice straw was fermented for 15 days and then utilized in MFCs featuring activated carbon anodes and zinc cathodes. The system reached a peak voltage of 1.166 ± 0.081 V and a current of 4.719 ± 0.219 mA on day 9, yielding a maximum power density of 0.707 ± 0.054 mW/cm² and an internal resistance of 18.749 ± 2.581 Ω. Furthermore, chemical oxygen demand decreased by 77.5%, indicating effective organic matter degradation. The pH shifted from acidic to 4.89 ± 0.08, while conductivity rose to 175.438 ± 8.084 mS/cm, reflecting favorable electrochemical conditions for microbial activity. These findings confirm rice straw fermentate as a viable MFC substrate, offering a twofold benefit: generating renewable energy while fostering sustainable waste utilization.