Fabrication of lipase immobilized-carboxylated cellulose nanocrystals as biocatalyst for enzymatic hydrolysis of palm oil and its kinetical study

Abstract

This research focuses on the production of free fatty acids (FFA), one of the essential components in the oleochemical industry, through the enzymatic hydrolysis process of palm oil at low temperature and pressure using cellulose nanocrystals (CNCs) as lipase immobilization support. Furthermore, the kinetic behavior of this hydrolysis reaction with the presence of lipase immobilized-CNCs (lipase@CNCs) was studied to find the optimum condition for designing the reactor. According to FTIR and TEM analyses, CNCs were successful in immobilizing lipases, as ascertained by the appearance of amide peaks from the formation of bonds between CNCs and lipases and the thickening of the surface of the CNC morphology after immobilization. As a result, the optimum immobilization conditions were obtained at a lipase concentration of 1.5 mg/mL, an immobilization time of 2 h, and the CNCs/EDC ratio of 1:3. Moreover, the Michaelis-Menten model with the inhibition product fitted with the experiment and lipase@CNCs has the highest Vmax value at a temperature of 40 °C of 15.53 mM/h with a KM of 99.80 mM and an Ea of 41.07 kJ/mol. The simulation results show that the semi-batch reactor can achieve a higher conversion at the beginning of the reaction with a conversion of 28%. Therefore, using lipase@CNCs in hydrolysis processes is expected to be one of the strategies that can overcome the limitations associated with existing methods in terms of high energy consumption.