Integrated electrosynthesis and biosynthesis for the production of adipic acid from lignin-derived phenols

Abstract

We show that adipic acid (AA), a major building block for polyamides like Nylon-6,6, can be synthesized from lignin-derived feedstock by combining electrochemical hydrogenation with biotransformation. Up to 68% yield of cyclohexanol from phenol at 69% coulombic efficiency is achieved for electrochemical hydrogenation, and further, the electrochemical hydrogenation of an aromatic mixture as gained from lignin depolymerization allows 83% yield. Subsequent biotransformation of cyclohexanol with recombinant Pseudomonas taiwanensis VLB120 gains AA at a rate of 0.02 g L⁻¹ h⁻¹ with a yield of up to 61% in 5 h.