Making Tomorrow's Bioenergy Yeasts Strong

USDA ARS
By Marcia Wood
August 25, 2011

Cornstalks, wheat straw, and other rough, fibrous, harvest-time leftovers may soon be less expensive to convert into cellulosic ethanol, thanks to U.S. Department of Agriculture (USDA) scientists' studies of a promising new biorefinery yeast.

The yeast—Saccharomyces cerevisiae strain NRRL Y-50049—successfully ferments plant sugars into cellulosic ethanol despite the stressful interference by problematic compounds such as furfural (2-furaldehyde) and HMF (5-hydroxymethyl-2-furaldehyde) in fermenters, according to molecular biologist Zonglin Lewis Liu with USDA's Agricultural Research Service (ARS). Liu works at ARS' National Center for Agricultural Utilization Research in Peoria, Ill.

ARS is USDA's principal intramural scientific research agency. Liu's research supports the USDA priority of developing new sources of bioenergy.

The troublesome compounds, created during dilute acid pre-treatment of the crop leftovers, inhibit yeast growth and reduce ethanol yields. In particular, they damage yeast cell walls and membranes, disrupt yeast genetic material such as DNA and RNA, and interfere with yeast enzymes' fermentation abilities.

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