Immobilization of acidic lipase derived from Pseudomonas gessardii onto mesoporous activated carbon for the hydrolysis of olive oil

Mesoporous activated carbon (MAC) derived from rice husk is used for the immobilization of acidic lipase (ALIP) produced from Pseudo monas gessardii. The purified acidic lipase had the specific activity and molecular weight of 1473 U/mg and 94 kDa respectively. To determine the optimum conditions for the immobilization of lipase onto MAC, the experiments were carried out by varying the time (10-180 min), pH (2-8), temperature (10-50 degrees C) and the initial lipase activity (49 x 10(3), 98 x 10(3), 147 x 10(3) and 196 x 10(3) U/l in acetate buffer). The optimum conditions for immobilization of acidic lipase were found to be: time-120 min: pH 3.5; temperature-30 degrees C, which resulted in achieving a maximum immobilization of 1834U/g. The thermal stability of the immobilized lipase was comparatively higher than that in its free form. The free and immobilized enzyme kinetic parameters (K-m and V-max) were found using Michaelis-Menten enzyme kinetics. The K-m values for free enzyme and immobilized one were 0.655 and 0.243 mM respectively. The immobilization of acidic lipase onto MAC was confirmed using Fourier Transform-Infrared Spectroscopy, X-ray diffraction analysis and scanning electron microscopy. (C) 2009 Elsevier B.V. All rights reserved.