Yeast strain boosts efficiency of biofuel production

The sugars are glucose — a six-carbon sugar that is relatively easy to ferment, and xylose — a five-carbon sugar that has been much more difficult to use in ethanol production.

The work to develop the yeast strain was a collaborative effort led by researchers at the University of Illinois, the Lawrence Berkeley National Laboratory, the University of California and energy giant BP.

Yeasts feed on sugar and produce various waste products, some of which are useful to humans. One type of yeast, Saccharomyces cerevisiae, has been used for centuries in baking and brewing because it efficiently ferments sugars and in the process produces ethanol and CO₂. The biofuel industry also uses the yeast to convert plant sugars to bioethanol.

But while Saccharomyces cerevisiae is good at feeding on glucose — a building block of cellulose and the primary sugar in plants — it cannot use xylose, a secondary — but significant — component of the lignocellulose that makes up plant stems and leaves. Most yeast strains that are engineered to metabolise xylose do so very slowly.