Efficient Synthesis of Pyruvic Acid from Biomass based on Gas-Liquid-Solid Triphase Bioelectrochemical Cascade...

The enzymatic synthesis of pyruvic acid (PyA) from biomass-derived lactic acid (LA) using oxidases under mild conditions represents a promising sustainable route. However, its efficiency is hindered by insufficient O₂ mass transfer and undesired PyA degradation resulting from the enzymatic byproduct H₂O₂. Herein, we present an gas-liquid-solid triphase bioelectrochemical reaction system that can address these two challenges symmetrically. This design ensures an efficient supply of O₂ from the air phase to the lactate oxidase (LOx) active zone, thereby overcoming the mass-transfer constraint of oxygen. Simultaneously, the in situ electro-oxidation of H₂O₂ minimizes the degradation of PyA. Consequently, the reaction system achieves a production rate of 54.34 µM h^-1 U^-1, which is 63-fold greater than that of conventional liquid-solid diphase enzymatic systems. Mathematical modeling and electrochemical studies revealed that enhanced local O₂ levels and efficient H₂O₂ removal are the keys to superior performance. This work provides a sustainable and efficient route for PyA biosynthesis while demonstrating the potential of engineered bioelectrocatalytic environments for green synthesis.