<p>Microbial fuel cells represented a robust renewable energy technology that generated secondary bioelectricity while remediating untreated wastewater containing high concentrations of toxic substances. This study examined the synergistic effect of microalgae (<i>Spirulina Arthrospira Platensis</i>) and microbial inoculum using tannery influents from the leather tanning process in a dual-chamber microbial fuel cell. The elemental and chemical properties of the anode and cathode solutions were characterized using atomic absorption spectroscopy, inductively coupled plasma mass spectrometry, ion chromatography, Fourier transform infrared spectroscopy, and analyses of biological oxygen demand and chemical oxygen demand. The maximum open circuit voltage and power density of the most effective batch (designated as MFC-1) reached 786 mV and 50.44 mW m^− 2, respectively, with a coulombic efficiency of 66.17% and a detoxification efficiency for chemical oxygen demand of 79.96%. The minimum open circuit voltage and power density, recorded for MFC-4, were 196 mV and 6.37 mW m^− 2, respectively. This configuration employed microalgae as a biocatalyst along with tannery influent in the presence of light. The maximum removal percentages of chromium, cadmium, copper, manganese, iron, bromide, nitrate, sulfate, and phosphate were 60.78%, 86.25%, 91.79%, 89.00%, 30.39%, 99.57%, 99.22%, 94.47%, and 100%, respectively. These findings indicated that further optimization of the synergistic microalgae and inoculum-based photosynthetic microbial fuel cell system was required to promote its implementation as a scalable green technology for addressing global energy and environmental challenges.</p> Graphical abstract <p></p>