Recent advances in microbial bidirectional extracellular electron transfer and its application for biomass resource utilization

<p indent="0mm">Electroactive microorganisms (EAMs) play a crucial role in biomass resource utilization. EAMs possess efficient extracellular electron transfer (EET) capabilities, including outward EET (electrons released from microorganisms to external receptors) and inward EET (electrons absorbed from external donors to microorganisms), enabling bidirectional electron exchange between microorganisms and extracellular medium. Depending on the bidirectional EET function, technologies driven by EAMs such as microbial fuel cells, microbial electrofermentation, and microbial electrosynthesis could achieve efficient recovery and utilization of biomass energy and carbon resources. However, the application of these technologies still faces key challenges such as low EET efficiency and a lack of regulation strategies. Therefore, this paper outlines the latest advancements in microbial bidirectional EET mechanisms, focusing on multi-scale regulatory strategies to improve microbial EET efficiency, and reviews the latest progress of EAMs in biomass resource utilization. It also provides a perspective on the current challenges and future development directions, aiming to promote research and application of biomass resource utilization driven by microbial bidirectional EET.