ABSTRACT
In common with other fungi, yeasts are aerobic organisms that metabolize their nutrients oxidatively, although alcoholic fermentation is the most noticeable feature of a number of yeasts. Contrary to common belief, however, only about half of all yeast species can ferment sugars; these are facultative anaerobic. Interest in yeast metabolism has stemmed largely from the ability of certain species, notably Saccharomyces, to ferment sugars and produce ethanol and carbon dioxide. This capability forms the basis for the production of alcoholic beverages and leavened bakery products. Selection of appropriate strains of the baker’s, brewer’s, and wine yeasts has resulted in a high degree of domestication. Not surprisingly, glycolysis in yeast was one of the first biochemical pathways to be explored; studies on sugar metabolism were later extended to other energy-yielding pathways, intermediary metabolism, and their regulation.
