LAUSR

This study deals with the immobilization of amyloglucosidase within agarose using method of entrapment. Enzyme was produced from Aspergillus fumigatus KIBGE-IB33 and then partially purified using 40% ammonium sulphate saturation. Using 40 gl−1 concentration of agarose and adjusting 3.0 mm size of hydrogels, maximum entrapment yield (78%) was obtained. The kinetic behavior was slightly changed after immobilization as reaction time and reaction temperature increases from 5.0 min (soluble) to 10.0 min (immobilized) and 60 °C (soluble) to 65 °C (immobilized), respectively while, pH optima remained same (pH 5.0). Substrate saturation kinetics revealed that Km was increased from 1.47 to 4.215 mg ml−1 while, the value of Vmax decreased from 947 to 611 kU mg−1 for soluble and entrapped amyloglucosidase, respectively. The stability profile of amyloglucosidase also significantly improved after entrapment in agarose hydrogels at 50, 60 and 70 °C for 120 min with retention of 77, 59 and 25% residual activity, respectively. Furthermore, the t1/2 of soluble and immobilized amyloglucosidase at 60 °C was 167 and 375 min respectively. Due to increase in reusability for various subsequent cycles of entrapped amyloglucosidase, about 8.73 mg ml−1 increase in glucose production was observed as compared to soluble enzyme.Graphical Abstract