Immobilization of Porcine pancreas lipase on fiber-like SBA-15 mesoporous material

An immobilized enzyme had been prepared by incorporation of Porcine pancreas lipase (PPL, 4.6 nm x 2.6 nm x 1.1 nm) in the channels of fiber-like SBA-15 by virtue of the hydrogen bonding interactions between the abundant weakly acidic hydroxyl groups of the support and the lipase. The physical adsorptions of PPL on the fiber-like SBA-15 mesoporous material in buffer solution with different pH values (pH 5-10) and times (0-36 h) had been studied. A high lipase loading (926 mg enzyme per gram silica) can be obtained, but it disagreed with the high catalytic activity. The adsorbed maximum activities were observed at pH 6.0 and 3 h. The optimal pH of the hydrolysis of triacetin for the immobilized and free PPL was at 7.0. The immobilized PPL showed much more excellent adaptability of the hydrolysis of triacetin compared to free PPL during pH 6.0-9.0. Meanwhile, the thermal stability of the catalyst and its reusability were tested by performing subsequent reaction cycles of hydrolysis of triacetin. The activity of the immobilized PPL fell off rapidly to be 40% of its original activity after five successive batch reactions, because the weakly adsorbed PPL was leached out from the channels. (C) 2009 Elsevier B.V. All rights reserved.