Application of microbial fuel cell utilizing orange peel waste and cocoa fermentation wastewater for renewable and sustainable energy alternatives

Abstract

High reliance on petroleum and coal-based energy poses a significant challenge for environmental sustainability. To address this issue, it is crucial to explore renewable and sustainable energy alternatives. One promising solution is the use of microbial fuel cells (MFC), which are bio-electrochemical systems capable of generating electrical energy through conversion and catalyzation reactions by microorganisms under anaerobic conditions. MFCs can utilize acidic biomass substrates to produce bioelectricity, including waste from agricultural and domestic sectors. In Indonesia, cocoa and oranges are major agricultural commodities, but their production also leads to significant waste generation. Cocoa processing results in solid waste and cocoa fermentation wastewater, while high orange consumption leads to substantial peel waste. This study aimed to investigate the potential of using microbial fuel cells to produce energy from orange peel waste and cocoa fermentation wastewater. It is expected that the use of both wastes enhanced the production of electrical energy due to their high conductivity. The waste is converted into bioelectricity using MFCs with sustainable waste management technology. The dual chamber MFC system is connected by a salt bridge made of 0.1 M KCl and 12.5 g of agar powder. The electrode materials used Cu as the cathode (+) and Zn as the anode (-), cut into pieces measuring 9 x 4 cm. Solution testing consisted of voltage, current, temperature, pH, and organic acids. The solutions tested included 100% cocoa bean fermentation waste, 100% orange peel extract, cocoa bean fermentation wastewater, and various mixtures of orange peel extract and cocoa bean fermentation waste. The study results indicated that the most optimal MFC composition was achieved through the stability of the voltage and current values, resulting from the metabolism of a mixed substrate of cocoa bean fermentation waste and orange peel extract in equal proportions (50:50). Microbial metabolic activity through a fermentation process could break down complex compounds into simpler compounds, which then generating energy. The increase in voltage value is attributed to the lower pH solution, resulting in a larger electric current, particularly in waste mixtures with equal composition of ingredients.

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Identifiers

DOI

10.1088/1755-1315/1477/1/012042

Journal

IOP Conference Series: Earth and Environmental Science

Year

2025