Scientist IDs genes that promise to make biofuel production more efficient, economical

August 19, 2010

A University of Illinois metabolic engineer has taken the first step toward the more efficient and economical production of biofuels by developing a strain of yeast with increased alcohol tolerance.

Biofuels are produced through microbial fermentation of biomass crops, which yield the alcohol-based fuels ethanol and iso-butanol if is used as the microbe to convert sugars from biomass into biofuels.

"However, at a certain concentration, the biofuels that are being created become toxic to the yeast used in making them. Our goal was to find a gene or genes that reduce this toxic effect," said Yong-Su Jin, an assistant professor of microbial genomics in the U of I Department of Food Science and Human Nutrition and a faculty member in the U of I's Institute for Genomic Biology.

Jin worked with , the microbe most often used in making ethanol, to identify four genes (MSN2, DOG1, HAL1, and INO1) that improve tolerance to ethanol and iso-butanol when they are overexpressed.

"We expect these genes will serve as key components of a genetic toolbox for breeding yeast with high ethanol tolerance for efficient ethanol fermentation," he said.

To assess the overexpressed genes' contribution to the components that have limited production, the scientists tested them in the presence of high concentrations of (10%), ethanol (5%), and iso-butanol (1%) and compared their performance to a control strain of S. cerevisiae.

Overexpression of any of the four genes remarkably increased ethanol tolerance, but the strain in which INO1 was overexpressed elicited the highest ethanol yield and productivity—with increases of more than 70 percent for ethanol volume and more than 340 percent for ethanol tolerance when compared to the control strain.

According to Jin, the functions of the identified genes are very diverse and unrelated, which suggests that tolerance to high concentrations of iso-butanol and might involve the complex interactions of many genetic elements in yeast.

"For example, some genes increase cellular viability at the expense of fermentation. Others are more balanced between these two functions," he said.

"Identification of these genes should enable us to produce transportation fuels from biomass more economically and efficiently. It's a first step in understanding the cellular reaction that currently limits the production process," he said.

Further study of these should increase alcohol tolerance even further, and that will translate into cost savings and greater efficiency during biofuel production, he added.

Explore further: 'Drunk' fruit flies could shed light on genetic basis of human alcohol abuse

More information: The article appears in the August 20 issue of the Journal of Biotechology.

Related Stories

Displacing petroleum-derived butanol with plants

January 8, 2009

As a chemical for industrial processes, butanol is used in everything from brake fluid, to paint thinners, to plastics. According to a University of Illinois researcher, butanol made from plant material could displace butanol ...

Sugar-hungry yeast to boost biofuel production

March 29, 2010

Engineering yeast to transform sugars more efficiently into alcohols could be an economically and environmentally sound way to replace fossil fuels, say scientists presenting at the Society for General Microbiology's spring ...

Recommended for you

'Hog-nosed rat' discovered in Indonesia

October 6, 2015

Researchers working in Indonesia have discovered a new species of mammal called the hog-nosed rat, aptly named after its features, that scientists said they had never been seen before.

Ancestors of land plants were wired to make the leap to shore

October 5, 2015

When the algal ancestor of modern land plants first succeeded in making the transition from aquatic environments to an inhospitable shore 450 million years ago, it changed the world by dramatically altering climate and setting ...

Stress in adolescence prepares rats for future challenges

October 5, 2015

Rats exposed to frequent physical, social, and predatory stress during adolescence solved problems and foraged more efficiently under high-threat conditions in adulthood compared with rats that developed without stress, according ...


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.