Direct Enzymatic Assay for Alcohol Oxidase, Alcohol Dehydrogenase, and Formaldehyde Dehydrogenase in Colonies of Hansenula polymorpha

A procedure is described for the qualitative direct identification of alcohol oxidase, alcohol dehydrogenase, and formaldehyde dehydrogenase in yeast colonies. The method has been applied successfully to isolate mutants of Hansenula polymorpha with altered glucose repression of alcohol oxidase.