Bioelectricity Generation from Fruit Waste in a Dual-Chamber Microbial Fuel Cell

Abstract

Fruit waste is highly biodegradable and prone to rapid spoilage, which can lead to odour generation, greenhouse gas emissions, and environmental pollution if not properly managed. This study investigated the use of fermented fruit waste as a substrate for simultaneous electricity generation and organic matter degradation in a dual-chamber microbial fuel cell (MFC). Shewanella oneidensis (S. oneidensis) inoculum densities, lactic acid bacteria (LAB) addition, and initial substrate concentrations, expressed as chemical oxygen demand (COD), were varied to assess their impact on power density and COD removal efficiency. Among the conditions tested, an initial COD of 5000 mg/L with an inoculum density of OD 600 = 0.4 produced the highest maximum power density of 14.25 mW/m 2 and 70% COD removal. Higher inoculum density or LAB addition reduced MFC performance. However, the effect of substrate concentration was non-monotonic, with performance increasing at 10,000 mg/L but decreasing at 15,000 mg/L at a fixed inoculum density of OD 600 = 0.8. These results demonstrate that balancing bacterial loading and substrate concentration is essential for efficient electricity generation and support further evaluation of MFCs for fruit-waste bioenergy recovery.