Sustainable bioelectricity production in wetland-microbial fuel cells: The role of carbon-based wire and Echinodorus cordifolius as a nutrient source

Abstract

Achieving stable bioelectricity production in wetland-microbial fuel cells (WMFCs) remains challenging due to material degradation and fluctuating environmental conditions. This study investigates the long-term performance of carbon-based electrodes and wires in WMFC systems by assessing cathodic physiochemical properties and rhizosphere metabolomics under light (700 μmol·m⁻²·s⁻¹) and dark conditions. Over 150 days, carbon-based wire systems generated 3.7 times higher bioelectricity than commercial copper-based wires. By the final day, the Plant + Carbon wire system achieved a power density of 31.71 ± 7.11 mW/m², compared to 8.59 ± 5.35 mW/m² in the Plant + Copper wire system. Light intensity and cathodic temperature strongly influenced bioelectricity, with higher generation during the light period (8.28 ± 2.93–12.29 ± 5.56 mW/m²) than in darkness (7.08 ± 3.27–7.15 ± 4.26 mW/m²). Interestingly, planted systems consistently exhibited more stable power generation than unplanted systems, likely due to enhanced rhizosphere activity and distinctive metabolite profiles that supported electron transfer and temperature adaptation. Metabolomic analysis revealed up-regulated metabolites, including 10-undecenoic acid and carnitine derivatives, which may function as nutrients, electron acceptors, and thermoprotectants under diurnal temperature fluctuations. These findings highlight the role of wetland plants and carbon-based materials in improving WMFC resilience, ensuring operational stability, and enabling long-term bioelectricity generation.