Oxidation of glucose to gluconic acid using a colloidal catalyst containing gold nanoparticles and glucose oxidase

A simple method for the preparation of colloidal catalysts of the aerobic oxidation of glucose, viz., metal polymeric complexes of gold or its alloy with silver, as well as complexes containing glucose oxidase, was developed. The complexes containing glucose oxidase were synthesized by the covalent immobilization of enzyme in aqueous medium (in the absence of toxic chemicals and solvents) on the shell of the alternate maleic acid copolymer covering a core made of nanogold or its alloy. The catalysts obtained were studied by transmission electron microscopy, spectrophotometry, IR spectroscopy, and light scattering. All the catalysts were active and selective in the process of the aerobic oxidation of glucose to gluconic acid (H2O2 registration method), whereas the catalytic activity of glucose oxidase was 73–96% (relative to the introduced enzyme). The highest activity was found for the colloidal catalysts containing gold and silver alloy in the core at pH 9.0 and T = 50 °C (registration of glucose and gluconic acid by 1H NMR). 1H NMR spectroscopy was used for the first time for the registration of glucose and gluconic acid in such reactions.