Science & Technology - Posted by Phyllis Picklesimer-Illinois on Monday, August 23, 2010 15:38 - 2 Comments 
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(No Ratings Yet) Loading ...More efficient biofuels from better yeast
Breeding yeast with high tolerance for efficient ethanol fermentation is expected to translate into cost savings and greater efficiency during biofuel production. (Credit: iStockphoto)
U. ILLINOIS (US)—Engineers believe a new strain of yeast with increased alcohol tolerance is the first step toward more efficient and economical production of biofuels.
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The text of this article by Futurity is licensed under a Creative Commons Attribution-No Derivatives License.
Biofuels are produced through microbial fermentation of biomass crops, which yield the alcohol-based fuels ethanol and iso-butanol if yeast 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,” says Yong-Su Jin, assistant professor of microbial genomics at the University of Illinois.
“Our goal was to find a gene or genes that reduce this toxic effect.”
Jin worked with Saccharomyces cerevisiae, 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 says.
Details are published in the August 20 issue of the Journal of Biotechology.
To assess the overexpressed genes’ contribution to the components that have limited biofuel production, the scientists tested them in the presence of high concentrations of glucose (10 percent), ethanol (5 percent), and iso-butanol (1 percent) 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.
The functions of the identified genes are quite diverse and unrelated, which suggests that tolerance to high concentrations of iso-butanol and ethanol might involve the complex interactions of many genetic elements in yeast, Jin says.
“For example, some genes increase cellular viability at the expense of fermentation. Others are more balanced between these two functions.
“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.”
Further study of these genes should increase alcohol tolerance even further, and that will translate into cost savings and greater efficiency during biofuel production, he adds.
The research was supported by the Samsung Advanced Institute of Technology.
More news from the University of Illinois: www.aces.uiuc.edu/news/
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2 Comments
Uncle B
Microbes enslaved to make more and better fuels are part of the battle! Americans are in love with spark ignited , low compression, piston and cylinder style liquid fueled engines1 this is where remarkable fuel saving changes can be made. Simply by going to proven Euro diesel technology, a full 40% improvement can be realized, but for some unfathomable notions of the oil barons propaganda machines this has not happened!
Extremely high compression, fuel injected, ethanol specific engines are much more fuel efficient than the current crap – nothing changes in America!
Plug-in Hybrids are all the rage! Totally battery cars are coming down the pipes! The automotive manufacturers see the writing on the wall! gasoline prices are about to jump! They are betting less and less on the gasoline.ethanol follies and looking for a better solution! Will better engines come about?
First, we should decide on the best engine, fuel cell or what-ever – then we should teach the microbes what to produce! Keep in mind, diesels are a full 40% more efficient than current gasoline engines due primarily to better thermodynamics due to higher compression factors! Bugs can make bio-diesel too! and it goes a lot further down the road.
The effect of different genes on alcohol tolerance may have relevance in the study of alcoholism. As most people know, some people cannot drink at all while others have no problem with large amounts of any alcoholic beverage. Yeast and men share a large number of genes. Are the four used in this study among them?