Immobilization of Fungal (3-Glucosidase on Silica Geland Kaolin Carriers

摘要

(3-Glucosidase is a key enzyme in the hydrolysis of cellulose for producingfeedstock glucose for various industrial processes. Reuse of enzyme through immobiliza-tion can significantly improve the economic characteristics of the process. Immobilizationof the fungal β-glucosidase by covalent binding and physical adsorption on silica gel andkaolin was conducted for consequent application of these procedures in large-scaleindustrial processes. Different immobilization parameters (incubation time, ionic strength,pH, enzyme/support ratio, glutaric aldehyde concentration, etc.) were evaluated for theireffect on the thermal stability of the immobilized enzyme. It was shown that theimmobilized enzyme activity is stable at 50 °C over 8 days. It has also been shown that inthe case of immobilization on kaolin, approximately 95% of the initial enzyme wasimmobilized onto support, and loss of activity was not observed. However, covalentbinding of the enzyme to silica gel brings significant loss of enzyme activity, and only35% of activity was preserved. In the case of physical adsorption on kaolin, gradualdesorption of enzyme takes place. To prevent this process, we have carried out chemicalmodification of the protein. As a result, after repeated washings, enzyme desorption fromkaolin has been reduced from 75 to 20-25% loss.