Marine Photosynthetic Microbial Fuel Cell for Circular Renewable Power Production

Abstract

Marine photosynthetic microbial fuel cells (mpMFCs) can utilize marine photosynthetic microorganisms to drive electrical energy-generating electrochemical reactions. Due to improved ionic mobility and superior electrical conductivity of seawater, it is a suitable electrolyte for operating bio-electrochemical devices at operating elevated salinities. This study examined the use of seawater as a conducting medium in two-chambered MFCs to enhance power production in conjunction with a marine photosynthetic biocathode as an alternative to the abiotic chemical cathode. Using a modified BG11 seawater medium as catholyte, marine cyanobacteria were grown and maintained in the MFC cathode compartment. After a significant quantity of biomass had formed, it was harvested for use as the substrate for anode microorganisms. Isolated marine cyanobacteria from photosynthetic biocathode were identified using 16 s rRNA and Sanger DNA sequencing. In electrochemical characterization, mMFC, maximum power density (P_max) was 147.84 mWm⁻² and maximum current density (J_max) reached 1311.82 mAm⁻². In mpMFC, P_max was 104.48 mWm⁻² and J_max was 1107.27 mAm⁻². P_max was 53.14 mWm⁻² and J_max was 501.81 mAm⁻² in comparable freshwater MFC employing platinum catalyst, which proves that mMFC and mpMFC worked better. Dapis pleousa and Synechococcus moorigangaii were identified as dominant marine cyanobacteria. It was demonstrated that mpMFC, operated using seawater and employing a cyanobacteria biocathode, is suitable for circularized renewable energy production. The outcomes of this study imply that mpMFCs are good candidates for circular renewable energy production.