The covalent immobilization of trypsin at the galleries of layered γ-zirconium phosphate

Assorted trypsin immobilization trials were thoroughly conducted and compared to identify an efficient enzyme immobilization at the galleries of amine preintercalated γ-zirconium phosphate. That was, (a) direct trypsin binding by physical adsorption, (b) coupling of enzyme to glutaraldehyde (GA) activated carrier, (c) trypsin immobilization by GA crosslinking, (d) incorporating bovine serum albumin (BSA) as a spacer during the immobilization by covalently coupling to GA activated carrier or by covalent trypsin crosslinking with GA. We reported here that covalent immobilization of trypsin by using GA as a crosslinking agent and BSA as a spacer was superior to other immobilization strategies investigated. In this study, the experimental parameters in each step of the immobilization procedure, such as the concentration of the preintercalation agent, the crosslinking agent, the spacer and trypsin, etc., were investigated to improve the efficiency of trypsin immobilization. A reasonable enzymatic activity recovery at 75.6% and improved thermal stability were achieved. The optimum pH value and optimum temperature of immobilized enzyme were determined.