BI-ENZYMATIC REACTION FOR ALCOHOL OXIDATION IN ORGANIC MEDIA - FROM PURIFIED ENZYMES TO CELLULAR-SYSTEMS

The oxidation of n-butanol to butyraldehyde by the bienzymatic system of alcohol oxidase (from Pichia pastoris)/catalase was studied in orde r to analyze the effect of organic media on the functioning of this sy stem. Microaqueous, two-phase, and aqueous media were used, with three kinds of enzymatic preparations: whole cells, crude extract, and puri fied alcohol oxidase (with or without added catalase). Syntheses were carried out in flasks or in an oxygen probe reactor to investigate kin etics and yield of the reaction. The points of interest involved the r ole of water in enzyme activity, the effect of internal diffusion limi tations in the various systems, and the possibilities offered by organ ic media concerning the transfer of butanol, oxygen, and butyraldehyde . The cellular system was found to be active in low-water media. Parti cular attention was directed to the case of H2O2, a hydrophilic compou nd, and to the crucial role of catalase, which was found to function i n microaqueous media.