Prof finds new way to produce ethanol 'fast and efficiently'
A yeast that has long been used to brew and bake now can help create ethanol fuel from sugars that used to be useless in the process.
Yong-Su Jin, a professor of food science and human nutrition at the University Illinois, has been working on genetically engineering yeasts to bring forth biofuels from sugars like galactose that normally go to waste.
Now, leading a team of researchers from Illinois, the Lawrence Berkeley National Laboratory, the University of California at Berkeley and Seoul National University, with funding from BP, Jin has managed to use xylose sugar, found abundantly in stems and leaves, to make ethanol.
Also on the team are postdoctoral researcher Suk-Jin Ha and graduate student Soo Rin Kim.
Yeast is good at making ethanol as a waste product when it encounters the common, six-carbon sugar glucose – its main limit being the toxicity to the yeast when the alcohol level reaches around 14 percent.
Saccharomyces cerevisiae, a fungus whose last name means "beer," has not been effective in turning the five-carbon wood sugar, xylose, into ethanol. It goes for the glucose first.
Jin is fond of comparing the situation to giving his kids meat and broccoli – they might eat the broccoli, but only after cleaning the plate of meat.
An expensive enzyme helps with the xylose, but Jin's work puts the fungus to work without that enzyme.
"I engineered a strain of yeast to produce ethanol fast and efficiently, saving money and generating a larger yield," he said.
The research paper is in the Proceedings of the National Academy of Sciences.
The Energy Biosciences Institute, a BP-funded initiative, supported the research, and Jin said that the industry could be using the current research industrially in a short time, possibly two years.
Jin and his colleagues make the yeast consume both types of sugar at the same time.
A bonus was that Saccharomyces cerevisiae can convert both the sugars into ethanol in the same time it would take to convert one sugar.
"You can make the same amount of ethanol in half the time," Jin said.
His recombinant techniques previously came to fruition in work with galactose in red seaweed.
Red seaweed involves both glucose and galactose.
Jin's team found three genes in Saccharomyces cerevisiae that could be used to increase galactose fermentation by 250 percent, according to an article in the journal article in "Biotechnology and Bioengineering."