Using of silica particles as porogen for preparation of macroporous chitosan macrospheres suitable for enzyme immobilization

Porous chitosan macrospheres were prepared at the first time by using silica particles as porogen, and the optimal weight ratio of silica to chitosan during preparation was determined. Scanning electron microscopy micrographs showed that the support with silica as porogen (support I) had a much more porous surface structure than the support without porogen (support II). Both supports were applied to immobilize β-galactosidase from Aspergillus oryzae. Much higher specific activity and yield of galactose hydrolysis products were observed for the support I. Properties of both immobilized enzyme were determined and compared with the free enzyme, satisfactory results were obtained in thermostability, pH arid operational stability, Michaelis constants K _m and in maximum velocity of hydrolysis (V _m). Suggested method allow to prepare chitosan macrospheres as immobilized enzyme carrier with moreporous surface structure and more active reaction groups.