Evaluation and immobilization of α-amylase produced from Bacillus amyloliquefaciens on different supports

This research aims to partially purify the alpha-amylase enzyme produced from Bacillus amyloliquefaciens, then immobilization α- amylase to convert the enzyme soluble form to the insoluble form on various supports i.e., eggshell membranes, gelatin and calcium alginate. Also, the optimum conditions for the free and immobilized enzyme on calcium alginate were evaluated i.e. pH values, temperatures, substrate concentrations, metal ions and studying the stability of the immobilized enzyme. Results showed an increase in -amylase activity after dialysis from 699.09 µmM/L/min to 2312.43 µmM/L/min. The purified α-amylase was immobilized with eggshell membranes adsorption, gelatin crosslinking by glutaraldehyde and by entrapment within Ca-alginate. The retention activities of eggshell, gelatine and Ca-alginate immobilization were 82.70, 81.98 and 73.63%, respectively. Concerning the factors affecting the free and immobilized Ca-alginate activity, the acquired results indicated that the optimum pH value was found to be 7.0 for each form and the optimum temperature for immobilized α-amylase of free form were 60 and 50°C, respectively. Kinetics parameters, Km and Vmax were estimated and were found to be 1.15 mg/ml and 1419.19 µmM/L for free enzyme. While these values for immobilized form, Km was 1.45 mg/ml and Vmax was 1153.63 µmM/L. The reusability of immobilized α-amylase was found to be up to 7 cycles. Therefore, the immobilization process improved the properties and stability of the purified alpha-amylase, increasing its potential for reuse in industrial processes in an economical and inexpensive manner compared to using the enzyme in its free form.