Co-immobilization of a rhodium catalyst and LDH on a carbon electrode using a covalent graft strategy for electrosynthesis of l-lactate in a bipolar electrochemical system

Abstract

This work demonstrates a wireless electroenzymatic platform using carbon microsphere electrodes co-immobilized with a rhodium catalyst and lactate dehydrogenase (LDH) for integrated NADH regeneration and pyruvate-to-L-lactate conversion in a bipolar electrochemical system. The 3D “aggregate reactor” architecture, functionalized via diazonium grafting, Rh coordination, and covalent enzyme coupling, enables spatial coupling of cofactor recycling and biocatalysis, while HPLC revealed a L-lactate production rate of 0.04 mM cm⁻² h⁻¹ under 12.5 V cm⁻¹ with plenty of carbon beads attributed to enhanced mass transport. This wireless, scalable design eliminates wiring constraints and offers modular adaptability for sustainable synthesis of chiral chemicals.