Cross-Linked Enzyme Aggregates of β-Galactosidase from Different Source by Dialdehyde Starch as Cross-Linker

The method of using dialdehyde starch (DAS) as cross-linking agent and bovine serum albumin (BSA) as protective agent for preparing β-galactosidase cross-linked enzyme aggregates (CLEAs) was investigated and high activity residue of 53.8 % for K. lactis β-galactosidase and 55.2 % for A. oryzae β-galactosidase was obtained. Polyethylene glycol 400 as precipitant was applied. The effect of oxidation degree of DAS and amount of bovine serum albumin (BSA) on the activity of CLEAs was discussed. The shape and surface morphology of the CLEAs were examined by SEM. Comparing with K. lactis β-galactosidas CLEAs, the A. oryzae β-galactosidase CLEAs have higher thermal stability, and better performance on the affinity toward the substrate, which related to the structure of CLEAs. A. oryzae β-galactosidase CLEAs was more suitable for lactose hydrolysis in industries.