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

## TL;DR

A mix of three bacteria types improves wastewater cleaning and electricity generation more than using any single type alone.

## Contribution

A novel microbial consortium of Bacillus, Lysinibacillus, and Lactococcus enhances wastewater treatment and bioelectricity production in microbial fuel cells.

## Key findings

- The bacterial consortium achieved 84.4% COD removal from poultry wastewater.
- The consortium generated a maximum power of 170 mW/m², outperforming individual strains.
- Synergistic interactions among the three bacterial strains significantly improved MFC performance.

## Abstract

Cleaning polluted water while also generating renewable electricity is a major scientific goal. One promising approach uses helpful bacteria that can break down waste in water and release electrons, which can be captured as electrical energy. In this study, we tested three different types of naturally occurring bacteria, both individually and combined as a group, to see how well they could clean very dirty water from poultry processing and how much electricity they could produce at the same time. Each type of bacteria was placed in a device that produces electricity directly from biological activity, and their performance was monitored for one month. The study found that the group of bacteria working together produced more electricity and removed more pollution from the water than any of the bacteria tested alone. The mixed group cleaned about 84% of the waste in the water, which was higher than the cleaning ability of each single type. It also produced the strongest electrical output. These results show that using several bacteria with different strengths can greatly improve both water cleaning and electricity generation. This approach may help to develop more sustainable technologies for treating industrial wastewater while recovering useful energy.

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, Lysinibacillus sphericus A1, Bacillus cereus A2 and Lactococcus lactis 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 B. cereus A2 and L. lactis A4. Meanwhile, the lowest power of 52 mA/m2 was recorded during testing of L. lactis A4, at 650 mA/m2 and 120 mV. Compared with single cultures, the consortium produced approximately 15% higher power density than L. sphericus A1, about 29% higher than B. cereus A2, and more than threefold higher than L. lactis 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.