Optimization and Immobilization of alpha-amylase from <i>Bacillus subtilis</i> in calcium alginate and calcium alginate – cellulosic residue beads
Abdallah Herizi, Rachid Souilah, Djaffar Djabali, Boubekeur Nadjemi
Abstract
In this study, Alpha amylase from Bacillus subtilis was immobilized by entrapment in Calcium Alginate beads (CA). To improve the properties of these beads, alginate was blended with Cellulosic Residue (CR) obtained from sorghumstarch extraction. The conditions of entrapment were optimized for a maximum immobilization yield (Y%) by mathematical statistics, where the 23-full factorial design of experiments was used. The properties of calcium alginate beads were improved by comparing the activity of immobilized enzymes in the hydrolysis of starch. The activity of the immobilized enzyme by Calcium Alginate /Cellulosic Residue (CA/CR) was found to be higher than the Calcium Alginate method. Zn2+ and Cu2+ have inhibitory effects on both immobilized enzymes. The Bacillus subtilis immobilized in alginate can be reused for 7 cycles with 12.7 μmol of reduced sugars and 6 cycles for the entrapped enzyme in CA/CR with 30 μmol of reduced sugars.