Microbial Nanowires: Next-Generation Conductors for Bioenergy Harvesting

Microbial nanowires represent a transformative advancement in bioenergy science, offering a novel mechanism forextracellular electron transport (EET) that can be harnessed for sustainable energy generation. These protein-based conductivefilaments, produced by certain electroactive bacteria such as Geobacter and Shewanella species, enable microbes to transferelectrons across cell membranes to external electron acceptors such as metal oxides or electrodes. This unique capability hasimmense implications for microbial fuel cells (MFCs), bioremediation, and electro-fermentation. Unlike traditional conductivematerials, microbial nanowires are biodegradable, self-assembling, and functionally dynamic under ambient environmentalconditions. Recent discoveries have revealed the complex structure of nanowires, often comprising multi-heme cytochromes ortype IV pili modified with aromatic amino acids, which contribute to long-range electron conductivity. Their integration intobioelectrochemical systems significantly enhances current output and efficiency. This review synthesizes current knowledge ofmicrobial nanowire biology, electrochemical behavior, and engineering strategies to optimize their conductive properties. It alsohighlights future directions in synthetic biology and materials science for scalable bioenergy solutions. As global energy demandsgrow, microbial nanowires stand at the forefront of next-generation, eco-friendly energy technologies, bridging the gap betweenliving systems and electrical networks.