Abstract: AB-8 macroporous resin was used as a carrier to immobilize lysozyme by glutaraldehyde cross-linking. The preparation conditions, enzymatic characteristics, microstructure and antimicrobial efficacy of immobilized lysozyme were explored. Immobilized lysozyme prepared by 4 h immobilization at 25 ℃, an enzyme-to-carrier ratio of 1:200 and a glutaraldehyde concentration of 0.3 g/100 mL presented the highest relative activity. The immobilized lysozyme showed significant improvements over free lysozyme in heat and acid tolerance. Trough a comparative analysis of their Michaelis Menten Equations, we found that immobilization resulted in a decrease in the affinity of lysozyme with chitosan, the substrate. After fifth repeated use, the immobilized lysozyme retained 57.6% of its original activity. The immobilized enzyme had good antimicrobial effect on pure milk.

Key words: immobilization, macroporous resin, lysozyme, enzymatic properties