Exploring Electrical Activity of a Bacterial and Yeast Cell for Potential Production of Power in a Tropical Setting

Abstract

This study investigated and compared the individual and combined electricity-generating potential of Saccharomyces cerevisiae and Lactobacillus bulgaricus in double-chambered microbial fuel cells (MFCs) in Makurdi, Benue State, Nigeria. The experimental setup consisted of two identical MFC units run under similar conditions with a fixed one thousand Ω external resistance. Electrical parameters including open circuit voltage (OCV), voltage across resistor, current output, conductivity, temperature, and pH were monitored over 7 days. Results showed that OCV values ranged from 3.6 mV to 686.9 mV in the S. cerevisiae system and from 76.8 mV to 732.3 mV in the Lactobacillus system. Current output increased progressively in both systems with values ranging from 0.0 mA to 0.6 mA for S. cerevisiae, and 0.0 mA to 0.7 mA for L. bulgaricus. The voltage across the external resistor varied between 2.3 mV and 658.5 mV in the yeast-based MFC and 44.4 mV and 702.9 mV in the Lactobacillus system. Anode conductivity increased during operation, ranging from 34.9 µS/cm to 580.7 µS/cm in the yeast system and 815.1 µS/cm to 1866.0 µS/cm in the Lactobacillus system, showing improved ionic mobility and substrate degradation. Anode pH values varied between 5.6 and 4.2 in the yeast MFC and 3.7 and 4.9 in the Lactobacillus MFC due to microbial metabolic activities. Temperature remained within the mesophilic range of 29.6°C to 32.6°C in the anode chamber, and 21.6°C to 30.0°C in the cathode chamber, providing suitable conditions for microbial growth and bioelectricity production. The yeast-based MFC produced higher peak power output of 0.4935 mW, while the Lactobacillus system produced 0.4333 mW. Overall, the findings show that both microorganisms can generate electricity in MFCs, although the yeast system produced slightly higher peak electrical output while the Lactobacillus system exhibited more sustained performance.