Bioelectricity Generation from Cucumis sativus Waste Using Microbial Fuel Cells: A Promising Solution for Rural Peru

This study addresses two critical challenges in rural Peru: the mismanagement of agro-industrial waste and the limited access to electricity. Over 40,000 tons of Cucumis sativus (cucumber) waste are generated annually in Peru, most of which is discarded without valorization. Microbial fuel cells (MFCs) offer a sustainable solution by converting organic waste into bioelectricity via electrogenic microorganisms. To evaluate the bioenergy potential of cucumber waste, three single-chamber MFCs were constructed using graphite and zinc electrodes under an external resistance of 100 ohms. The systems were inoculated with acclimated microbial consortia, and electrical, physicochemical, and microbiological parameters were monitored over 35 days. Results showed a maximum voltage of 0.589 V, a peak current of 2.292 mA, and a power density of 0.622 mW/m2. Chemical oxygen demand (COD) was reduced by over 80%, and oxidation-reduction potential (ORP) reached 459.76 mV. Internal resistance was 24.515 ± 1.237 Ω, indicating high energy efficiency. Taxonomic analysis revealed a predominance of Gammaproteobacteria, Bacilli, Bacillus, Acetobacter, and Clostridium, confirming a functionally diverse and electroactive microbial community. These findings demonstrate that cucumber waste is a viable substrate for MFCs and support its potential for integrated waste valorization and decentralized bioenergy generation in rural Peruvian contexts.