Bioelectrocatalysis is an interdisciplinary research field combining biocatalysis and electrocatalysis via the utilization of materials derived from biological systems as catalysts to catalyze the redox reactions occurring at an electrode. Bioelectrocatalysis synergistically couples the merits of both biocatalysis and electrocatalysis. The advantages of biocatalysis include high activity, high selectivity, wide substrate scope, and mild reaction conditions. The advantages of electrocatalysis include the possible utilization of renewable electricity as an electron source and high energy conversion efficiency. These properties are integrated to achieve selective biosensing, efficient energy conversion, and the production of diverse products. This review seeks to systematically and comprehensively detail the fundamentals, analyze the existing problems, summarize the development status and applications, and look toward the future development directions of bioelectrocatalysis. First, the structure, function, and modification of bioelectrocatalysts are discussed. Second, the essentials of bioelectrocatalytic systems, including electron transfer mechanisms, electrode materials, and reaction medium, are described. Third, the application of bioelectrocatalysis in the fields of biosensors, fuel cells, solar cells, catalytic mechanism studies, and bioelectrosyntheses of high-value chemicals are systematically summarized. Finally, future developments and a perspective on bioelectrocatalysis are suggested.

The development of electrochemical catalytic conversion of 5‐hydroxymethylfurfural (HMF) has recently gained attention as a potentially scalable approach for both oxidation and reduction processes yielding value‐added products. While the possibility of electrocatalytic HMF transformations has been demonstrated, this growing research area is in its initial stages. Additionally, its practical applications remain limited due to low catalytic activity and product selectivity. Understanding the catalytic processes and design of electrocatalysts are important in achieving a selective and complete conversion into the desired highly valuable products. In this Minireview, an overview of the most recent status, advances, and challenges of oxidation and reduction processes of HMF was provided. Discussion and summary of voltammetric studies and important reaction factors (e. g., catalyst type, electrode material) were included. Finally, biocatalysts (e. g., enzymes, whole cells) were introduced for HMF modification, and future opportunities to combine biocatalysts with electrochemical methods for the production of high‐value chemicals from HMF were discussed.

Increasing attention has been paid to bioelectrochemical nitrogen fixation (e-BNF) as a promising approach to achieve the NH 3 synthesis under mild conditions. However, currently developed microbial e-BNF systems all rely on diffusible mediators to deliver redox equivalents inside the bacteria. Challenges of using diffusible mediators include toxicity, inefficient transmembrane diffusion, mediator inactivation, mediator contamination, and low energy efficiency. To date, e-BNF through transmembrane electron uptake without using diffusible electron mediators has not yet been reported. Herein, we describe a genetic strategy to engineer cyanobacterium Synechococcus elongatus PCC 7942 with transmembrane electron transfer (TET) ability to realize e-BNF without the addition of soluble mediators. The engineered S. elongatus PCC 7942 strain Se-nif with N 2 fixation activity was further transformed with an outer membrane protein cytochrome S OmcS, which contributes for the extracellular electron transfer (EET) ability of Geobacter sp. The engineered Senifom strain exhibited enhanced TET ability resulting in an approximately 13-fold higher NH 3 production rate than the corresponding Se-nif strain. The Faradaic efficiency of the Senifom e-BNF system was calculated to be approximately 23.3%, which is higher than the previously reported e-BNF systems. The electron pathway of the obtained extracellular electron was briefly analyzed and an extracellular electron uptake mechanism in the Senifom strain was proposed. This work demonstrates that a genetically engineered conduit can facilitate transmembrane electronic communication from the electrode to living cells, thereby providing insights into bioelectrosynthesis technology, especially the e-BNF systems and ammonium production.

Combination of electrochemical methods, quantum mechanical calculations, bioinformatics, and bioengineering allows understanding the photoexcited electron transfer process and set the basis for artificially tuning photo-bioelectrocatalysis.

The ability to establish successful and efficient extracellular electron transfer (EET) between bacteria and electrode surfaces is critical for the development of mediated microbial electrochemical technologies. Here, we describe a phenazine-based mediator system to facilitate electron transfer from the model bacterium Escherichia coli during glucose metabolism. Phenazine redox mediators were experimentally evaluated, demonstrating distinct mediated currents, dependent on mediator structure. Our results show that the choice of a mediator with the appropriate redox potential is not the single aspect to consider when rationally designing future mediator-based EET systems.