Immobilization of [alpha]-amylase on reactive modified fiber and its application for continuous starch hydrolysis in a packed bed bioreactor

In this study, the enzyme [alpha]-amylase was immobilized on reactive modified poly (ethylene terephthalate) fiber. The activities of free [alpha]-amylase and immobilized [alpha]-amylase were compared in a batch starch hydrolysis system. Optimum pH and Michaelis-Menten constants were determined for both free [alpha]-amylase and immobilized [alpha]-amylase. The immobilization shifted the optimum pH to a higher level. The Michaelis-Menten constant values (Km) of the immobilized [alpha]-amylase and free [alpha]-amylase were obtained as 11.94 and 6.61mg/mL, respectively. The experiments indicated that the immobilization increased the thermal stability of the [alpha]-amylase. The immobilized [alpha]-amylase, easily separated from the reaction media, could be used effectively for 15 cycles with 65% retention of the initial activity. Moreover, the immobilized [alpha]-amylase was effectively used in packed bed bioreactor for continuous starch hydrolysis throughout 6.5h without loss of activity. Different starches (e.g., potato and wheat) were hydrolyzed by the immobilized [alpha]-amylase in continuous process. The results indicate a potential use of this immobilized enzyme system for the construction of packed bed bioreactors to be used in the hydrolysis of the starch. [PUBLICATION ABSTRACT]