Rapid enzymatic hydrolysis of crambe oil catalyzed by castor seeds lipases

Oil hydrolysis is an important industrial process that requires high temperatures and pressure, or expensive enzymatic catalysts; it is, therefore, necessary to seek the use of inexpensive raw materials and process enhancement. In this work, a rapid and eco-friendly method, using ultrasound power, was successfully employed to hydrolyze crambe (Crambe abyssinica Hochst.) oil using lipase enzymes directly from castor (Ricinus communis L.) seeds, in oil-free and fresh forms. A yield of 86 % conversion of triglycerides into free fatty acids (FFA) was achieved in 5 min using castor fresh seeds and 73 % of conversion when performing the reaction with oil-free seeds. The operational conditions of ultrasound power, mass ratio of buffer solution and oil, catalyst, and total substrate were evaluated using a central composite rotatable design (CCRD). The hydrolysis yield was optimized by response surface methodology (RSM). The optimum conditions were approximately 70 % of ultrasound power (350 W), 1.79 buffer solution/oil mass ratio, and 0.25 catalyst/substrate mass ratio for fresh seeds. For the oil-free seeds, the optimal conditions found were 68 % (340 W) of ultrasound power, 1.67 buffer solution/oil mass ratio, and 0.06 catalyst/substrate mass ratio. Mathematical modeling was applied to the experimental kinetic data, and it was possible to predict FFA concentration values from independent experiments.