In Massachusetts, chemical engineers and biologists at MIT have found a simple way to make yeast produce more ethanol from sugars: Spike the mixture they’re growing on with two common chemicals. Adding potassium and an acidity-reducing compound helps the yeast tolerate higher concentrations of the ethanol they’re making without dying.
Aided by those “supplements,” traditionally underperforming laboratory yeast made more ethanol than did industrial strains genetically evolved for ethanol tolerance. The supplements also enabled lab yeast to tolerate higher doses of high-energy alcohols such as butanol, a direct gasoline substitute.
In other “firsts,” the researchers described the mechanism by which alcohols poison yeast; they defined two genes that control ethanol tolerance; and they modified those genes in lab yeast to make them out-produce the industrial strains — even without the supplements.
