Optimization and characterization of immobilized thermostable α-amylase from germinating Sword bean ( (Jacq.) DC.) seeds on DEAE-cellulose and chitosan bead for operational stability.

Thermostable α-amylase from germinating Sword bean ( (Jacq.) DC.) seeds has been successfully immobilized on DEAE-cellulose (ICgAmy1) and chitosan bead (ICgAmy2) support materials. Optimum conditions of immobilization for DEAE-cellulose and chitosan bead revealed 97% and 96% immobilization yield, respectively. The optimum pH and temperature of both DEAE-cellulose and chitosan bead immobilized α-amylases were pH 7 and 70°C. Both ICgAmy1 and ICgAmy2 were high stability over a wide pH range of pH 5-9 and a temperature range of 70-90°C. In addition, ICgAmy1 and ICgAmy2 led to an operationally stable biocatalyst with above 74% and 76% residual activity after 10 reuses, respectively. Immobilized α-amylases showed high storage stability with 81% (ICgAmy1) and 85% (ICgAmy2) residual activity after 120 days of storage. The easy immobilization process on low-cost, biodegradable, and renewable support materials exhibited an increase in the enzyme operation range and storage stability which reduces production costs. This makes immobilized amylases an effective biocatalyst in various industrial applications especially a potential candidate for bioethanol production, a key renewable energy source.