An enzymatic method for the production of methyl R-(＋)-N-(2,6-dimethylphenyl)alanine has been developed. The process consists of the stereoselective hydrolysis of the racemic esters catalyzed by Candida rugosa lipase (CRL). The conversion and reaction speed were evaluated by some critical reaction parameters such as pH, temperature, enzyme concentration, subsidiary and stirring speed. Under the conditions of pH 6.4, 35 ℃, 250 mg of CRL, 2 g of polyethylene glycol (PEG) and 160 r•min^－1, the best results of reaction were obtained, which contained 1 mmol of methyl (±)-N-(2,6-dimethylphenyl)alanine as well as 100 mL of 0.2 mol/L phosphate buffer solution (PBS). Meanwhile, enzyme concentration and temperature were benefical for the hydrolysis of esters. In a word, methyl R-(＋)-N-(2,6-dimethylphenyl)alanine was separated from the reaction and op-tically active N-acylalanines were prepared.

Key words: Methyl N-(2,6-dimethylphenyl)alanine, resolution, conversion, reaction speed, Candida rugosa lipases