Upgrading carbon monoxide to bioplastics via integrated electrochemical reduction and biosynthesis

Abstract

It is challenging to obtain high-value hydrocarbons that are longer than C3 via electrochemical CO2/CO reduction. Integrating electrochemical CO2/CO electrolysers with a downstream bioreactor is one solution for obtaining high-value long-chain products, but the electrolytes in these two systems are mismatched, preventing smooth integration. Here we demonstrate a porous solid electrolyte reactor that produces highly selective and electrolyte-free acetate and couple it with a biosynthesis system for generating C4+ polyhydroxybutyrate bioplastic. A finely tuned electrolyte containing biocompatible salt medium with acetate can be directly injected into the downstream bioreactor without any separation or salt-mixing processes. In the optimized coupled platform, Ralstonia eutropha bacteria can grow with acetate generated from the CO electrocatalytic reduction reactor, and produce bioplastic as the final value-added product. Integrating electrochemical CO electrolysers with a bioreactor can yield high-value long-chain carbon products, but the electrolytes for the two systems are mismatched. Now, a porous solid electrolyte reactor, which can produce acetate directly in bioelectrolyte, is demonstrated. Direct integration with a bioreactor produces bioplastic from CO via the acetate intermediate.