Efficient hydrolysis of starch by α-amylase immobilized on cloisite 30B and modified forms of cloisite 30B by adsorption and covalent methods

In this paper, alpha-amylase from Bacillus subtilis was successfully immobilized on three supports. First, alpha-amylase was immobilized on cloisite 30B via the adsorption method. Then cloisite 30B was activated with tosyl chloride and epichlorohydrin. These activated supports were used for covalent immobilization of alpha-amylase, and their enzymatic activities were effectively tested in the starch hydrolysis. The results demonstrated that the specific activity of alpha-amylase immobilized on cloisite 30B was 2.39 +/- 0.03, for alpha-amylase immobilized on activated cloisite 30B with epichlorohydrin was 1.96 +/- 0.05 and for alpha-amylase immobilized on activated cloisite 30B with tosyl chloride was 2.17 +/- 0.05 U mg(- 1). The optimum pH for the activity of free alpha-amylase was 7, but for alpha-amylase immobilized on cloisite 30B was 8, and for alpha-amylase immobilized on activated supports was 7.5. The immobilized enzymes had better thermal resistance and storage stability than free alpha-amylase, and they also showed excellent reusability.

Automated summary

This study successfully immobilized alpha-amylase from Bacillus subtilis on three different supports using adsorption and covalent immobilization methods. The immobilized enzymes showed improved thermal and storage stability, higher specific activity, and good catalytic performance in starch hydrolysis compared to free enzymes.