Immobilization of α-amylase from Aspergillus fumigatus using adsorption method onto zeolite

Abstract

Abstract The stability of enzymes which play an important role as biocatalysts in many industrial processes is a persistent challenge with significant impact on production costs. In this study, improvement of the stability of α-amylase obtained from Aspergillus fumigatus was attempted by immobilizing the enzyme onto zeolite using adsorption method. For purification, the isolated enzyme was subsequently subjected to centrifugation, fractionation, and dialysis. The native enzyme was found to have an optimum temperature of 50 °C, while the immobilized enzyme, the optimum temperature of 60 °C was found. The immobilized enzyme was found to have the K M value of 11.685 ± 0.183 mg mL−1 substrate and V max of 1.406 ± 0.049 μmol mL−1 min−1, while for the native enzyme, the K M value of 3.478 ± 0.271 mg mL−1 substrate and the V max of 2.211 ± 0.096 μmol mL−1 min−1 were obtained. Furthermore, the immobilized enzyme displays the ΔGi of 106.76 ± 0.00 kJ mol−1 and t ½ of 90.40 ± 0.00 min, while the native enzyme, the values obtained are ΔGi of 104.35 ± 1.09 kJ mol−1 and t½ of 38.75 ± 1.53 min. As can be seen, the t ½ of immobilized enzyme is 2.38 times longer than that of native enzyme, justifying a very significant stability enhancement of the enzyme as a result of. Another important finding is that the immobilized α-amylase enzyme was able to retain its activity as high as 13.80 ± 1.19% activity after five cycles, indicating its potential for industrial use.