Electroactive Microbial Consortium of Bacillus, Lysinibacillus, and Lactococcus for Enhanced Wastewater Treatment and Bioelectricity Generation

Microbial fuel cell (MFC) technology represents a promising bioelectrochemical approach for the simultaneous generation of electricity and treatment of high-strength wastewater. However, the performance of MFCs strongly depends on the metabolic potential and synergistic interactions of the inoculated microbial community. This study evaluated the electrochemical activity and COD removal efficiency of three individual bacterial strains, <i>Lysinibacillus sphericus</i> A1, <i>Bacillus cereus</i> A2 and <i>Lactococcus lactis</i> A4, compared with a developed consortium under long-term operation using poultry slaughterhouse wastewater as a substrate. All inocula were tested in dual-chamber MFCs for 30 days, and performance indicators included power output, voltage, and removal of chemical oxygen demand (COD). The consortium showed the highest power of 170 mW/m² and the optimal voltage-current ratio at a current of 900 mA/m² and 245 mV under decreasing external resistance from 1000 to 50 Ω. The highest COD removal (84.4%) was also recorded, surpassing all pure cultures and demonstrating a significant improvement compared with <i>B. cereus</i> A2 and <i>L. lactis</i> A4. Meanwhile, the lowest power of 52 mA/m² was recorded during testing of <i>L. lactis</i> A4, at 650 mA/m² and 120 mV. Compared with single cultures, the consortium produced approximately 15% higher power density than <i>L. sphericus</i> A1, about 29% higher than <i>B. cereus</i> A2, and more than threefold higher than <i>L. lactis</i> A4. This study highlights the potential of a consortium as an efficient biocatalyst for MFC-mediated wastewater treatment and suggests that selecting complementary strains with diverse metabolic functions can substantially improve system performance.