One of the most well-known characteristics of yeast is the ability of Saccharomyces cerevisiae, baker's yeast, to ferment sugar to 2-carbon components, in particular ethanol, without completely oxidising it to carbon dioxide, even in the presence of oxygen, as many other microbes do. This fermentative ability is essential for the production of wine, beer and many other alcoholic beverages.
Why do Saccharomyces yeasts actually do this and what were the driving forces behind the evolution of this phenomenon?
