Study of the Cathodic Catalytic Mechanisms of Microalgae-Based Microbial Fuel Cells

Microbial fuel cells (MFC) are promising systems for wastewater treatment and electricity production; however, many technical and economic challenges must be overcome. One approach to improve MFC performance is the use of photosynthetic microorganisms at the cathode to supply oxygen and reduce aeration requirements. In this work, Chlorella sorokiniana was used as a cathodic biocatalyst, in order to supply oxygen while simultaneously obtaining high-value products. At the anode, an anaerobic mixed microbial culture was used as a biocatalyst. Different cathodic configurations were studied to evaluate the different cathodic catalytic mechanisms. Electrochemical characterization through cyclic voltammetry, polarization curves, biochemical analysis and SEM images was performed. Superior performance was achieved when employing microalgae as the cathodic oxygen source compared to systems relying on external aeration (128.7 mA/m2 vs. 45.2 mA/m2). The addition of methylene blue and sodium bicarbonate improved the current density (194.8 mA/m2 and 128.7 mA/m2). Results indicate that microalgae in the cathodic chamber could enhance MFC electrochemical performance and biomass production, boosting sustainable energy generation.