Integrated Electromicrobial Production of Itaconic Acid From CO2 at Liter-Scale Using Komagataella phaffii.

Coupling electrochemical CO2 reduction showing high selectivity with microbial biosynthesis offering metabolic versatility offers a promising strategy for converting CO2 into value-added products. We present proof-of-concept of electromicrobially producing the platform chemical itaconic acid (IA) from CO2 using a robust yeast chassis. The hybrid systems integrates in a single reactor electrochemical CO2 reduction with microbial synthesis using a synthetic autotrophic Komagataella phaffii strain. Thereby CO2 serves as carbon source while electrochemically generated formate from CO2 provides reducing power to sustain microbial growth and drive IA production, reaching average titres of 110.1 mg·L-1. While demonstrating the feasibility of directly coupling electrochemical and microbial processes within a single reactor, we reveal key challenges associated with integration, including limited system performance, variability in product titers, anodic oxidation of cathodic products, and constraints in energy efficiency. Despite these current limitations, our results establish the operational feasibility of integrated electromicrobial CO2 conversion using industrial yeast and highlight critical parameters for process intensification.