(602e) Harvesting Energy from Agricultural Waste Fermentation Using Microbial Fuel Cells

The production of biofuels from lignocellulosic biomass such as agricultural wastes has drawn great attention because of its abundance, low cost and environmental benefits. In order to increase energy recovery and generate CO₂-neutral renewable energy from biomass, electrons released during the fermentation step of a biomass conversion process can be utilized to generate bioelectricity. To achieve this, we are implementing to couple the ethanol fermentation system with a microbial fuel cell (MFC). The characteristics and operating parameters of biomass conversion to sugars used as carbon sources for microbial growth and ethanol production will be used to engineer, construct and implement different architectures of MFCs. Specifically, an H-type MFC with carbon graphite rod electrodes, Saccharomyces cerevisiae as the microorganism, and potassium ferricyanide (0.25 M) catholyte was studied. The maximum voltage obtained was 0.36 volts with a 470-kilo ohms resistance. The open-current voltage (OCV) was 0.424 volts. Substrate and ethanol concentration were monitored with a YSI biochemical analyzer. Cell growth in the fermentor was monitored with a spectrophotometer by measuring the optical density (OD) at 600 nm. Finally, the coulombic and energy efficiencies of the MFC system were estimated using voltage output from the H-type MFC obtained from batch fermentations.