Business Week July 19, 2004
FILL 'ER UP -- WITH STRAW AND YEAST
By Michael Arndt
Edited by Catherine Arnst
In the fairy tale, Rumpel-stiltskin could spin straw into gold. Now, a Canadian biotech company is using genetically modified yeast to improve the transformation of straw into ethanol.
Yeast has long been used to break down glucose in corn and ferment it into ethyl alcohol, which is then added to gasoline and sold as a motor fuel. But straw, corn stalks, and other crop leftovers contain xylose as well as glucose -- and natural yeast can break down only one sugar at a time. Nancy Ho, a molecular biologist at the Purdue University Laboratory of Renewable Resources Engineering, found that by adding three genes to yeast, the organism can convert both sugars simultaneously into ethanol. The new process boosts ethanol yields by 30% to 40%. Purdue has licensed the yeast to Iogen in Ottawa.