Abstract: Candida antarctica lipase B (CALB) was docked with trilinolein to obtain the active site composition of CALB. The free ε-NH2 residues of CALB were located far from the active site and a small part of –COOH was located at the active site. Given the distribution characteristics of the CALB reactive groups, MCM-41 was modified into G-MCM-41 having aldehyde groups or NH2-MCM-41 having amino groups. CALB was immobilized with G-MCM-41 by binding the aldehyde group to ε-NH2 with a loading capacity of 87.4 mg/g, and the activity of the immobilized enzyme was as high as 1 176 U/g. CALB was immobilized with NH2-MCM-41 by binding the amino group to –COOH with a loading capacity of 89.6 mg/g, and the activity the immobilized enzyme was only 672 U/g. The results confirmed the distribution of amino acid residues in the CALB molecule. Using first-grade soybean oil and phytosterol as substrates, the transesterification rate of the immobilized lipase was 87.4% under the optimum conditions established using response surface methodology.

Key words: molecular docking, active center, modification, MCM-41, immobilization, transesterification