Utilization of Methanol by Yeasts

This chapter reviews the metabolic features of the methanol-utilizing yeasts and compares them with those of other microorganisms. A number of methanol-utilizing yeasts and strains of yeasts has been shown to utilize methanol. These species are limited to several genera, which include both ascomycetous and asporogenous yeasts. All of them are facultative methylotrophs. The oxidation of methanol by alcohol oxidase is accompanied by the formation of a toxic compound, H2O2. Catalase is induced when the yeast is grown on a methanol medium. Subcellular localization of enzymes involved in methanol oxidation is a useful feature of the methanol-utilizing yeasts. A glutathione-dependent dehydrogenase, which uses nicotinamide adenine dinucleotide (NAD) as the electron acceptor is known to catalyze formaldehyde oxidation in various organisms, including the methanol-utilizing bacteria. Formaldehyde dehydrogenase has also been found in methanol-utilizing yeasts. Formaldehyde oxidation by dehydrogenase is favorable because it provides electrons for the respiratory chain to produce ATP. Another possible oxidation system for formaldehyde is catalase-catalyzed peroxidation