Glucose 2-oxidase (pyranose oxidase, pyranose:oxygen-2-oxidoreductase, EC 1.1.3.10) catalyses the oxidation of D-.glucose at carbon 2 in the presence of molecular oxygen producing D-glucosone (2-keto-glucose; D-arabino-2-hexosulose) and hydrogen peroxide(1). This enzyme is of great importance since the reaction product (D-glucosone) is an important precursor for biosynthesis of the antibiotic cortalcerone (2). On the other hand, D-glucosone has been shown to exhibit anti-cancer activity in vitro against some cancer cell lines. The  present work involves the conversion of D- glucose into D-glucosone in the presence of glucose 2-oxidase from Coriolus versicolor at high pressures with compressed air in a modified commercial reactor. The apparatus consists basically of one batch reactor (Micro Reactor Parr Instruments CO, 4843) with 25 ml of capacity equipped with agitation, temperature and pressure reading devices (3). Several parameters affecting biocatalysis at high pressures, up to 20 MPa, were investigated as follows: pressure, temperature, pH, enzyme concentration, enzyme immobilization and the presence of catalase. The conversion of D-glucose into D-glucosone in the presence of glucose 2-oxidase activity was investigated by using an  HPLC system. The data presented in this work revealed an increase in the rate of reaction as a function of pH in the following order: pH 8.0> pH 5.0> pH 6.5 in the presence of catalase. The presence of catalase was found to increase the rate of conversion of D-glucose both at high pressures as well as at NTP with or without bubbling with pure O2. The immobilized form of enzyme in a dialysis membrane  exhibited about 50% of activity compared with the free enzyme and it could be re-used several times without a significant loss of enzyme activity.

[1] Pacheco, V., Karmali, A., Journal of Industrial Microbiology and Biotechnology, 21, 1998 p.57.

[2] Amon, Jr., William, F., Geigert, J., Neidleman, S., United States Patent Office US 4423149, 1983.

[3] Karmali,  A.,  Coelho, J.P.,  Costa, D.P., Barbosa, A.R., Biocatalysis of Glucose 2-Oxidases from Coriolus Versicolor ant High Pressures, In Proceedings of 10th European Meeting on Supercritical Fluids, Colmar, (France), 2005.

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1. Enzymic catalysis in supercritical carbon dioxide