Activated alginate-montmorillonite beads as an efficient carrier for pectinase immobilization

Pectic compounds are responsible for turbidity in many juices. The elimination of these compounds, such as using pectinase can improve the appearance and storage stability of the products. In this study, the covalent immobilization of pectinase from Aspergillus aculeatus was studied on alginate-montmorillonite beads. The prepared beads were characterized by FT-IR and SEM. The immobilization procedure did not affect the optimal temperature (40 °C) of pectinase for achieving the maximum activity but the optimal pH changed was reduced from 5.5 to 5.0. A significant decrease in Michaelis constant (K_m) value was observed after immobilization, indicating the affinity of enzyme to the substrate has been enhanced after immobilization, although the thermal stabilities of both forms of enzymes were comparable. After 6 cycles reusing of immobilized enzyme, its initial activity was remained about 53%. Finally, the immobilized pectinase was applied for the clarification of pineapple juice, showing that the immobilized enzyme is promising for use in the fruit juice industry.