Abstract: Enantioselective esterification of racemic ketoprofen[2-(3-benzoylphenyl) propionic acid] was carried out in organic solvents by using celite adsorbed lipase as the catalyst. Factors influencing the activity of the immobilized lipase had been investigated. Among the seven lipases examined, the esterification activity of Lipase OF(from Candida rugosa) was the highest; the activity of immobilized lipase was improved as compared with free lipase; the optimum volume of buffer(0.1 mol/L Na₂HPO₄ NaH₂PO₄, pH7.0) for enzyme immobilization was 1m Lpergram lipase. Among the acyl receptors such as methanol, ethanol, n-propanol, n-butanol, noctanol, iso propanol and 2-ethylene chlorohydrin, n propanol was the best; In the mixed solvent system composed of a main solvent and a cosolvent, the esterification activity of lipase was higher than that in the single solvent system composed of the corresponding main solvent or cosolvent. The esterification activity of lipase was the highest when using cyclohexane or iso-octane, both of which have high lg Pvalues, as main solvents and toluene as cosolvent.

Key words: Ketoprofen, Immobilized lipase, Enantioselective esterification, Mixed solvent systems