The production of biofuels by fermentation is as old as mankind itself. The use of yeast (Saccharomyces cerevisiae) in the production of wine and beer, as well as bread, has been known from the time of the Rosetta Stone and the Bible. Nowadays, biotechnology is playing a major role in new advances in the fermentation of different substrates and in the production of ethanol, as well as in the production of biodiesel and many other biofuels. Advances in biotechnology have shed new light on ancient and well established technologies, bringing biofuels and mankind to a new, clean, sustainable, and bright future. A single and simple biotechnology method (electrophoretic karyotyping of intact chromosomes) has brought the entire ethanol industry in Brazil to new horizons.