Process for preparing a catalase-free oxidase and a catalase-free oxidase-containing yeast, and use thereof

摘要

The invention provides the preparation of an oxidase or oxidase-containing mixture by aerobic fermentation of a methylotrophic yeast, wherein a catalase-negative yeast is allowed to grow in a nutritive medium in the presence of: (a) a so-called inducing substrate that induces expression of the oxidase gene and may also be substrate for the oxidase, and (b) another source of carbon that is suitable for the yeast species chosen, the molar ratio of inducing substrate to other source of carbon being such that the yeast formed and the oxidase formed do not suffer any harmful effects from the oxidation of the inducing substrate. For example, methanol oxidase is formed by induction with methanol in the presence of glucose. Examples of yeasts are Hansenula polymorpha and Pichia pastoris. Specific ratios of inducing substrate and glucose as other carbon source are (0.025-3):1 and preferably (1-1.8):1. The yeasts are not capable of producing catalase, so that the oxidase produced can be used for producing hydrogen peroxide, e.g. when an alkanol is combined with methanol oxidase in a washing or bleaching process. The oxidase can also be used for qualitative and/or quantitative determination of a substrate for the oxidase, e.g. ethanol or amines, or be used as a catalyst for the oxidation of a substrate in chemical synthesis.