Burning questions: Exploring the limits of microbial electrochemical technology for industrial biotechnological applications.

Microbial electrochemical technology (MET) has proven to be a promising solution to overcome the redox and energy metabolic constraints, enabling high yields of biosynthesis beyond stoichiometric limits. While there is room for improvement in extracellular electron transfer rates and productivity of the target compounds, it is crucial to think in advance about which bioprocess could be electrified and what would face major challenges. In this opinion paper, I presented and addressed interfacial electron transfer capacity of MET, whether built on biofilm or planktonic cells, and also discussed the upper limits of the MET system for biosynthesis of chemicals accordingly. Potential future application scenarios of different MET were also briefly addressed. This opinion paper aims to encourage the community to rethink the design and development of microbial electrochemical technologies for potential future applications in industrial biotechnology.