Photosynthetic microbial fuel cell (PMFC) is an environmentally friendly sustainable technique for simultaneous wastewater treatment and power recovery. PMFC utilizes the microalgae to generate oxygen by photosynthesis process in the biocathode. Light sources and intensities have direct effect on chlorophyll pigment formation, photosynthesis processes and microalgae growth. In this study, Chlorella vulgaris was utilized as biocathode in PMFC fed with actual slaughterhouse wastewater. The biocathode was illuminated with florescent light as well as yellow, red and blue LED lights with light intensities of 67.46, 47.03, 26.18 and 4.70 µmol/m.s, respectively. Power output and microalgae growth were considered in evaluating the PMFC performance. Results demonstrated that the highest power output was 217.04 mW/m² generated under florescent light compared to 28.41, 171.08, and 21.65 mW/m² observed under yellow, red and blue LEDs, respectively. Additionally, statistical analysis was performed using fifth-degree polynomial model which fitted well the experimental data with a determination coefficient (R²) > 0.97. The results reflected a high confidence level in depicting the growth mechanism of Chlorella vulgaris under lighting sources with different light colors and intensities.