Production of Adipic Acid from Sugar Beet Residue by Combined Biological and Chemical Catalysis

Abstract Adipic acid is one of the most important industrial dicarboxylic acids and is used mainly as a precursor to nylon‐6,6. Currently, commercial adipic acid is produced primarily from benzene by a chemical route that is associated with environmental, health, and safety concerns. Herein, we report a new process to produce adipic acid from an inexpensive renewable feedstock, sugar beet residue by combining an engineered Escherichia coli strain and Re‐based chemical catalysts. The engineered E. coli converted d ‐galacturonic acid to mucic acid, which was precipitated easily with acid, and the mucic acid was further converted to adipic acid by a deoxydehydration reaction catalyzed by an oxorhenium complex followed by a Pt/C‐catalyzed hydrogenation reaction under mild conditions. A high selectivity to the free acid products was achieved by tuning the acidity of the Re‐based catalysts. Finally, adipic acid was produced directly from sugar beet residue that was hydrolyzed enzymatically with engineered E. coli and two chemical catalysts in a yield of 8.4 %, which signifies a new route for the production of adipic acid.