Synthesis of mesoporous silica templated by Pluronic F68 and its application in the immobilization of lipase

Mesoporous silica templated by Pluronic F68 was synthesized and characterized by TEM, N-2 adsorption-desorption isotherms and FT-IR spectra. The sample had a high specific surface area (761 m(2) g(-1)) and the mean pore diameter was 4.7 nm, indicating that it can be used as porcine pancreatic lipase (PPL) support. The physical adsorption of PPL on this mesoporous material in phosphate buffer solution with different pH values has been studied. The maximum adsorbed amount was observed at pH 7.0 and amounted to 826 mg g(-1) and the maximum activity value of immobilized PPL was 227 mu mol g(-1) min(-1). The optimal pH and temperature of the hydrolysis of triacetin for the immobilized PPL were at 8.0 and 45 A degrees C, while they were at pH 7.0 and 35 A degrees C for free PPL. The immobilized PPL showed excellent adaptability in higher pH and excellent heat resistance compared to free PPL. The retained activity of immobilized PPL was found to be ca. 50% of its original activity after the 5th reuse.