Integrating electrochemical and microbial processes for CO2 conversion at scale

Combining microbial with electrochemical conversion of CO 2 to gain valuable chemical compounds is of paramount importance, with this review providing an assessment of the current state of the scale-up. It introduces and critically examines both direct and indirect strategies that integrate electrochemical and microbial processes for CO 2 utilisation by highlighting the progress achieved at laboratory scales. These advancements have been instrumental in opening new frontiers and identifying fundamental challenges. However, many issues only emerge during scale-up, including limitations related to reactor design, mass transfer, and process stability. We illustrate the need for systematic investigations at pilot and industrial scales, not only to identify and overcome these scale-dependent challenges but also to identify and leverage advantages that come with process intensification and integration. Given the maturity of the technology, we call for setting mandatory essential performance metrics that allow thorough assessment and argue that it is now time to shift the focus toward larger scales to fully realise the potential of bio|electrochemical CO 2 conversion for sustainable chemical production.