Lipase-catalyzed hydrolysis of (R,S)-2,3-diphenylpropionic methyl ester enhanced by hydroxypropyl-β-cyclodextrin

The enantioselective hydrolysis of (R,S)-2,3-diphenylpropionic methyl ester ((R,S)-2,3-2-PPAME) catalyzed by lipase to (R)-2,3-diphenylpropionic acid ((R)-2,3-2-PPA) was studied in an aqueous system. The catalytic effects of different types of lipase were compared, and Candida antarctica lipase A (CALA) with higher catalytic activity and enantioselectivity was selected. Hydroxypropyl-β-cyclodextrin (HP-β-CD) was added to the aqueous system to increase the solubility of 2,3-2-PPAME, which resulted in an increase of 35.56% in substrate conversion remaining the high enantiomeric excess. The factors influencing the substrate conversion and the optical purity of product such as temperature, pH, concentrations of CALA and HP-β-CD, substrate loading, and reaction time were optimized. The optimal conditions for this reaction were obtained, including pH of 5.5, 30 mg/mL CALA, 25 mmol/L HP-β-CD, 0.12 mmol substrate, temperature at 60 °C, agitation speed at 400 rpm, and 48 h for reaction time. Under these optimal conditions, the substrate conversion was up to 44.70% and the optical purity of the product (R)-2,3-2-PPA was up to 98.20%. This work provides an efficient alternative method for lipase-catalyzed enantioselective hydrolysis of 2,3-2-PPAME to (R)-2,3-2-PPA by β-cyclodextrin inclusion in an aqueous reaction system of hydrolysis. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1355-1362, 2018.