Optimal immobilization of α-amylase from wheat (Triticum aestivum) onto DEAE-cellulose using response surface methodology and its characterization

• Using Box–Behnken technique, wheat α-amylase was optimally immobilized onto DEAE-cellulose.
• This immobilization resulted from combination of covalent attachment and ionic adsorption.
• The immobilized enzyme showed better thermostability and storage stability over free enzyme.

Response surface methodology was utilized to seek optimal parameters for immobilization and Box–Behnken design usage was found worthy with 86% immobilization of wheat α-amylase on DEAE-cellulose matrix under optimal condition. This immobilization was found to be a combination of covalent attachment as well as ionic adsorption. Analysis of variance showed that the obtained mathematical model is significant to carry out further studies. The biochemical properties of this bio-conjugate experienced a slight shift from the optimum of its free form equivalent. This change was found favourable with respect to its utilization in industrial sector. Optimal pH and temperature were 6.0 and 70 °C, respectively. Though there was not much change in optimum temperature but the immobilized enzyme was functionally active at higher temperatures. Immobilization showed positive effect when thermal inactivation at 67 °C resulted in first-order kinetics with t1/2 126 min. It retained 77% residual activity after 10 uses and 80% residual activity on 2 months of storage at 4 °C. These properties provide impetus for its utility for commercial purpose. This laboratory scale study revealed that immobilization successfully stabilized this enzyme-matrix assembly thus opening channel into numerous industries for cheap, cost-effective and environmentally friendly starch hydrolytic processes.

Figure optionsDownload as PowerPoint slide