(503b) Effect of the Hydrophobicity of Supports On the Lipase Immobilization and the Synthesis of Feruloylated Monoacyl- and Diacylglycerols

The influences of the hydrophobicity of porous support on the loading amount and the catalytic efficiency as well as the conformation of the immobilized lipase were investigated in the present work. Aerogels based on silica, which are extremely porous materials with high specific surface area and easy for surface modification, were chosen as support for immobilization. Controlling the coating of silica surface with methyl groups may change the hydrophilic material into the ones with different degree of hydrophobicity. Five kinds of silica supports with different hydrophobicities were prepared, and all the modified silica aerogels with immobilized CALB were used to catalyze the reaction of transesterification of ferulate with triolein to form ferulyl oleins. It was found that the hydrophobicity of the support had significant effect on the adsorption kinetics and capacity of lipase. More hydrophilic or more hydrophobic supports were more suitable for the immobilization of Candida Antarctica lipase B (CALB), and the adsorption capacities were 340 mg/g and 220 mg/g respectively. The support whose contact angle with water was about 100° had the least capacity. More importantly, the hydrophobicity of the support may also affect the conformation of the immobilized lipase. It was found that the catalytic efficiency highly depended on the hydrophobicity of the support. The target products feruloylated monoacyl- and diacylglycerols can only be produced through the catalysis of CALB immobilized on the hydrophobic support, and all the substrates turned to by-products when the support was hydrophilic.