Optimized synthesis of lipase-catalyzed l-menthyl butyrate by Candia rugosa lipase

The ability of lipase from Candida rugosa (Lipase AY-30) to catalyze direct esterification of l-menthol and butyric anhydride was investigated. Response surface methodology and 5-level-4-factor central composite rotatable design were employed to evaluate the effects of synthesis parameters, such as reaction time (2-10 h), temperature (25-65 °C), enzyme amount (10-50% of l-menthol), and substrate mole ratio of l-menthol to butyric anhydride (1:1-1:3) on mole percent conversion of l-menthyl butyrate by direct esterification. Based on the analysis of ridge max, the optimum synthesis conditions were as follows: reaction time 8.7 h, temperature 37.1 °C, enzyme amount 31.7%, and substrate mole ratio 1:2.6; the highest yield obtained was 72.6%.