Degradation of pectin by using pectinase immobilized on ion-exchange resin by ionic bond was studied in this work. Experiments were designed to find out suitable conditions for immobilization and to compare kinetic properties between immobilized enzyme and free enzyme. The experimental results showed that a suitable condition for immobilization which provided optimum activity was 0.2 ml/g(support) of enzyme concentration, pH of 3.5, temperature of 35℃ and contact and contact time of 4 hr. The optimum activity of immobilized enzyme was approximately 1.53-1.56 units per ml enzyme when the enzyme reacted with 1.0 wt/v% of pectin solution at pH of 3.5 and temperature of 35℃. The Michaelis-Menten constant of immobilized enzyme was 2.6 times less than that of free enzyme while the maximum velocity of reaction of immobilized enzyme was approximately 1.2 times greater than that of free enzyme. Effect of flow rate of substrate and concentration of substrate on activity of immobilized enzyme were studied in a packed bed reactor. It was found that degradation rate of substrate and pressure drop increased while the activity decreased rapidly when the flow rate increased. When the concentration of substrate increased, degradation rate and pressure drop of the reactor also increased. In the first period, 0.150 minutes, the activity of immobilized enzyme at high substrate concentration was higher than at low concentration. On the other hand, after 150 minutes, the activity of the enzyme at high concentration was lower. Operation stability of immobilized enzyme was studied by using 1.0 wt/v% of pectin solution as feed. Flow rate of substrate was 40 ml/min, and the reaction was carried out at a temperature of 35℃ and pH of 3.5. The result showed that 1800 ml of pectin solution was degraded completely in 45 minutes.
