Enantioselective esterification of (RS)-2-(4-chlorophenoxy)propionic acid via Carica papaya lipase in organic solvents

Carica papaya lipase (CPL) stored in the crude papain is found to be enantioselective for the kinetic resolution of (RS)-2-(4-chlorophenoxy)propionic acid via esterification in anhydrous organic solvents. Of the alcohols screened, trimethylsilylmethanol acted as the best acyl acceptor and gave the highest enzyme activity and enantioselectivity in anhydrous cyclohexane. The kinetic analysis at temperatures between 20 and 60°C indicated that CPL is thermally stable, giving a high E value of 113 at 20°C. A change of cyclohexane to other hydrophobic solvents resulted in better lipase performances. In comparison with the performances of other crude Candida rugosa lipases, Carica papaya lipase is more active, enantioselective and thermally stable.