Making Tomorrow's Bioenergy Yeasts Strong

In attempts to improve ethanol yield from cellulosic feedstocks, USDA ARS molecular biologist Zonglin Lewis Liu has identified a new strain of yeast that will not be affected by the presence of harmful by-products of cellulosic dilute acid pre-treatment. Saccharomyces cerevisiae strain NRRL Y-50049 was identified after years of research using a laboratory approach called "evolutionary engineering".

Results of their study show that the yeast strain NRRL Y-50049 was able to successfully ferment plant sugars into cellulosic ethanol, despite the presence of inhibitory by- products such as furfural (2-furaldehyde) and HMF (5-hydroxymethyl-2-furaldehyde) in fermenters. They also showed that in the nearly 7,000 genes in the S. cerevisiae genome, more than 350 may be involved in counteracting this stress. In addition, a gene called YAP1 was determined to act as a master gene to reduce the impact of furfural and HMF.

The research news can be seen at http://www.ars.usda.gov/is/pr/2011/110825.htm.