[Enzymatic resolution of racemic naproxen in a low aqueous-organic biphase system]

A stereoselective hydrolysis of the racemic naproxen methyl ester by immobilized lipase from Candida rugosa in a low aqueous-organic biphase system was studied. Support polar, water content, the logP value of organic phase and product inhibition effected the activity of immobilized enzyme. According to these reaction conditions, a low aqueous-organic biphase system for the continuous production of (S)-(+)-Naproxen was developed. The reaction was carried out in a continuous-flow closed-loop 50 mL stirred bioreactor packed with YWG-C6H5, a poorly polar synthetic support on which the lipase had been immobilized by adsorption. The aqueous phase was permanently remained in the reactor associated with the immobilized enzyme particles; the organic phase containing substrate was pumped through this reactor and emerged with the products. The continous-flow stirred bioreactor containing 75 mg lipase was allowed to operate continuously for 60 days at 30 degrees C with a 25% loss of activity, 900 mg of (S)-(+)-Naproxen (eep 95%) were producted.