Harnessing <i>Dangke</i> Whey as a Sustainable Nutrient Source for <i>Lactobacillus plantarum</i> in Microbial Fuel Cells for Bioelectricity Generation

Dangke whey is a liquid by-product of traditional cheese production in Enrekang, Indonesia, which still contains nutrients like sugar and lactose. This research investigates the potential of using Lactobacillus plantarum and Dangke whey as a substrate in microbial fuel cells (MFCs) for bioelectricity generation. Dangke whey, rich in lactose and nutrients, was tested as a carbon source in MFCs under varying whey concentrations (20, 80, and 100%) and agitation speeds (90, 120, and 150 rpm). The highest voltage output of 600 mV was obtained using 80% whey at 150 rpm stirring. Analysis revealed that lactose breakdown and acid production were key factors in bioelectricity generation. Additionally, four MFCs connected in series powered a red LED for 126 days, reaching a maximum voltage of 1,070 mV and a power density of 183.46 mW/cm2. This study demonstrates the potential utilization of Dangke whey as a sustainable, low-cost substrate for MFCs, contributing to dairy waste valorization and renewable energy generation.