Making tomorrow's bioenergy yeasts strong

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 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 growth and reduce ethanol yields. In particular, they damage yeast cell walls and membranes, disrupt yeast such as DNA and RNA, and interfere with yeast enzymes' fermentation abilities.

In research that began in 2003, Liu and coinvestigators have worked with dozens of strains of S. cerevisiae, a species already used to make ethanol from plant starch. Using a laboratory approach known as "evolutionary engineering," the scientists speeded up the microbe's natural adaptation to the hostile environment created by the inhibitors. NRRL Y-50049 was one result of these studies.

The scientists are discovering more about the genes and the multiple networks of genes that are likely responsible for the notable tolerance that this yeast has shown in laboratory tests with a 2-liter fermenter.

Their research suggests that, of the nearly 7,000 genes in the S. cerevisiae genome, more than 350 may be involved in counteracting stress. For instance, Liu and colleagues determined that a gene called YAP1 acts as a , orchestrating interactions of many related , so that they work together to reduce the impact of furfural and HMF.

Explore further: Commercial yeasts upgraded with an enzyme for biofuel production

More information: Peer-reviewed articles in Applied Microbiology and Biotechnology, Molecular Genetics and Genomics, and other scientific journals document the studies.

Related Stories

Wine-making yeast shows promise for bioethanol production

May 13, 2010

Researchers from the Stanford University School of Medicine have identified a gene in the yeast Saccharomyces cerevisiae that might be important for ethanol production from plant material, providing insights into the bioethanol ...

Recommended for you

A common mechanism for human and bird sound production

November 27, 2015

When birds and humans sing it sounds completely different, but now new research reported in the journal Nature Communications shows that the very same physical mechanisms are at play when a bird sings and a human speaks.

Study suggests fish can experience 'emotional fever'

November 25, 2015

(—A small team of researchers from the U.K. and Spain has found via lab study that at least one type of fish is capable of experiencing 'emotional fever,' which suggests it may qualify as a sentient being. In their ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.