Lipase catalyzed synthesis of oleyl oleate: Optimization by response surface methodology

Abstract

Lipase catalyzed production of oleyl oleate, which is an analogue of jojoba oil, was carried out using oleic acid and oleyl alcohol in the solvent-free system. Novozym 435, immobilized Candida antarctica lipase, was used as a biocatalyst. Response surface methodology (RSM) based on five-level, four-variable central composite rotatable design was used to evaluate the effects of important parameters on the production of oleyl oleate. Acid/alcohol molar ratio (0.5-1.5), enzyme quantity (2-10% w/w of substrates), reaction temperature (40-60°C), and reaction time (30-90 min) were chosen as process variables for the optimization. Among these parameters, enzyme quantity and acid/alcohol molar ratio have significant effects compared with temperature and time on the production of oleyl oleate. Optimum conditions were found to be a acid/alcohol molar ratio of 1, enzyme quantity of 7% (w/w), reaction temperature of 51°C, and reaction time of 75 min. The coefficient of determination (R 2 ) for the model is 0.97. Probability value is 2.9 ‐ 10 m 9 (P-value<0.01). This P-value demonstrates a very high significance for the regression model. The maximum oleyl oleate concentration predicted by the equation (737 g/L) agrees well with the experimentalvalue (734 g/L) obtained from the experimental verification at the optimum values.