Immobilization and kinetics of catalase onto magnesium silicate

Bovine liver catalase was immobilized covalently with glutaraldehyde, or glutaraldehyde + 3-aminopropionic acid as a spacer, onto magnesium silicate. The coupling time was determined as 2 h for immobilization. The pH and temperature optima as well as the changes in the kinetics (K-m, V-max, E-a) of the immobilized catalase was observed and discussed. Immobilized catalase preparations showed higher storage stabilities than free catalase. The half-life of free catalase, catalase immobilized via glutaraldehyde and catalase immobilized via glutaraldehyde + spacer were calculated as 2, 55 and 10 days at room temperature and 4, 85 and 107 days at 5 degreesC, respectively. The operational stability of the catalase immobilized via glutaraldehyde was higher than the catalase immobilized via glutaraldehyde + spacer. The remaining activity of the catalase immobilized via glutaraldehyde was about 90% and that of the catalase immobilized via glutaraldeyde + spacer was about 30% after 20 cycles of batch operation. (C) 2003 Elsevier Ltd. All rights reserved.