Immobilization of Glucose Oxidase on Sodium Alginate Microspheres

Glucose oxidase from Aspergillus niger was immobilized by covalent cross-linking on the surface of alginate microspheres obtained by the emulsification–internal gelation method. The catalytic properties of the free and immobilized enzyme were compared. The size of the resulting microspheres was less than 100 μm. Experiments have shown that the immobilized enzyme has an activity that is 40% lower than the free glucose oxidase, but it has a high level of activity in a wider range of temperatures and pH values. The kinetic parameters for native glucose oxidase are: the reaction rate limit is 0.341 mM min–1 and the Michaelis constant is 5.41 mM; for the immobilized enzyme the reaction rate limit is 0.203 mM min–1 and the Michaelis constant is 11.43 mM. Peaks corresponding to the formed covalent bonds between the enzyme and the carrier were revealed in infrared Fourier spectra of diffusion reflection of semi-products of biocatalyst synthesis. The synthesized biocatalyst can be used in the food industry as a bakery improver, in the chemical and pharmaceutical industry for production of gluconic acid, and in analytical chemistry for the determination of the glucose concentration.