<p>Microbial diversity plays a critical role in enhancing electron transfer mechanisms in microbial fuel cells (MFCs), directly impacting their efficiency, stability, and scalability. Electron transfer mechanisms are fundamental to the efficiency and scalability of electrochemical systems, influencing energy conversion, storage, and industrial applications. These mechanisms, including direct and mediated electron transfer, are crucial for microbial fuel cells, batteries, fuel cells, and photoelectrochemical devices. This review explores advancements in mediators, electrode materials, catalytic interfaces, and microbial consortia, particularly in terms of electron transfer mechanisms in microbes, to optimize bioelectricity generation. Furthermore, challenges related to commercialization, cost-effectiveness, system durability, and large-scale implementation are critically discussed, providing a roadmap for future developments in sustainable energy applications.</p> Graphical abstract <p></p>