Physical and chemical adsorption of Mucor java']javanicus lipase on SBA-15 mesoporous silica.: Synthesis, structural characterization, and activity performance

In this work a sample of SBA-15 mesoporous silica was synthesized and characterized by TEM, XRD, and N-2 adsorption. The sample had high value of specific surface area (1007 m(2) g(-1)) and total pore volume (2.1 cm(3) g(-1)). The pore diameter was 67 A, so it was large enough to accommodate protein molecules inside the channels. Immobilization by physical adsorption of a commercial lipase preparation from Mucor javanicus was performed at different pH values (pH 5-8). pH 6 gave the highest lipase loading and hydrolytic activity of the corresponding biocatalyst. Chemical modification of the SBA-15 via glutardialdehyde allowed also the enzyme immobilization through chemical adsorption. This preparation was active toward tributyrin hydrolysis. On the contrary, very low activity toward triolein hydrolysis was observed. The reduction of the size of the channels due the immobilization process has been suggested as a possible explanation.