Stabilization of α-amylase by using anionic surfactant during the immobilization process

This work describes the entrapment of alpha-amylase into butylacrylate-acrylic acid copolymer (BuA/AAc) using gamma irradiation. The effect of an anionic surfactant (AOT), the reuse efficiency, and kinetic behavior of immobilized alpha-amylase were studied. Covering of alpha-amylase with bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT) made the enzyme more stable than the uncovered form. The hydrolytic activity of the pre-coated immobilized alpha-amylase was increased below the critical micelle concentration (cmc) (10 mmol/L). The results showed an increase in the relative activity with increase in the degree of hydration. The pre-coated immobilized alpha-amylase showed a higher k(cat)/K(m) and lower activation energy compared to the free and uncoated-immobilized preparation, respectively. The results suggest that the immobilization of alpha-amylase is a potentially useful approach for commercial starch hydrolysis in two-phase systems. (C) 2005 Elsevier Ltd. All rights reserved.