Electrical Energy Generation by Microbial Fuel Cells With Microalgae on the Cathode

Abstract

Background. The possibility of converting organic compounds into electrical energy in microbial fuel cells (MFCs) makes MFCs a promising eco-friendly technology. However, the use of platinum or hexacyanoferrates may increase costs or lead to secondary environmental pollution. The use of microalgae in the cathode chamber is a promising solution to these problems. Objective. We aimed to establish the dependence of electrical energy generation and the efficiency of the appli­cation of a specific type of algae on the type and mode of lighting. Methods. In the study, two-chamber H-type MFC with salt bridge was used. Fermented residue after methanogenesis was used as inoculum in the anode chamber, and microalgae cultures Chlorella vulgaris, Desmodesmus armatus, and Parachlorella kessleri were used as inoculum in the cathode chamber. Results. MFCs with microalgae demonstrate the ability to generate current under different light sources. The maximum voltage for the MFC with an anode biofilm and with microalgae in the cathode chamber is 13–15% lower compared to the MFC with an abiotic cathode (840 ± 42 mV). The maximum current is 2–6% lower than the control (480 ± 24 mA) for the MFC with Chlorella vulgaris and the MFC with Parachlorella kessleri, and 8% higher for the MFC with Desmodesmus armatus compared to the MFC with an abiotic cathode. The MFCs with microalgae are capable of generating electrical energy for an extended period. Conclusions. With a pre-grown anodic biofilm, both the current and voltage maintain relative stability when the light source is changed. The potential use of solar lighting broadens the applicability of the MFCs with microalgae, as it eliminates the need for additional costs associated with artificial light sources.