Abstract
The efficiency of crambe oil hydrolysis using castor seeds as source of lipase was evaluated using two different forms of extract (in natura and oil-free seeds) to catalyze the reaction under different operational conditions. A central composite rotatable design (CCRD) was applied to evaluate the effects (temperature and mass ratio of buffer solution and oil, and catalyst and total substrate) onto the response (the final hydrolysis yield), and using Response Surface Methodology, hydrolysis yield was optimized. The enzymatic activity for in natura extract was 45.1 U g(-1), and 71.2 U g(-1) for oil-free extract. Although the activity of in natura was smaller, it was observed that after 30 days the activity remained the same, while oil-free enzymatic activity was reduced, 64.8 U g(-1) showing less stability. In addition, in natura seeds also have emulsifying proprieties, being more advantageous to the hydrolysis reaction. Kinetic studies were carried out in the optimal conditions achieving 87% for in natura and 85% for oil-free extract after 2 h of reaction; a low time of reaction in comparison with enzymatic hydrolysis performed with commercial lipases. The results show the potential of using vegetal lipases, as high hydrolysis conversions can be achieved under mild conditions and low times.