Baylor Awarded $492,000 to Study Ways to Make Ethanol Cheaper to Produce

May 21, 2008

by Frank Raczkiewicz

While the high cost of producing cellulosic ethanol still stands as one of the major hurdles of mass mainstream production, Baylor University researchers have been awarded a $492,000 grant from the U.S. Department of Agriculture to study the by-products created when making cellulosic ethanol and how many of those by-products may restrict the fermenting process. The inhibitory by-products are largely to blame for the current high cost of producing cellulosic ethanol. Ultimately, Baylor researchers hope to learn how to minimize the inhibitory effects of those by-products, thus reducing the cost to produce ethanol.

"The goal is to try to make the production of cellulosic ethanol cost-competitive to petroleum and this research will help lay the groundwork," said Dr. Kevin Chambliss, associate professor of chemistry and biochemistry at Baylor, who is leading the study. "We have already identified about 40 compounds that could be inhibitory and now we are going back through to check other compounds that are present and see how inhibitory they really are."

There are three main steps to make cellulosic ethanol: 1) the agricultural waste is first "cooked," which is called pretreatment, 2) the fiber is then liquefied into sugars, and 3) the sugars are fermented into ethanol.

Cellulosic ethanol is made from the non-food portion of many agricultural wastes. One of the more common wastes used is corn stover, which are the stalks and residue left over after harvest. The Baylor researchers will study corn stover by conducting the pre-treatment step different ways by varying temperature and how long the batch is "cooked." This will create varied samples and the researchers will test for enzyme and fermentation inhibition in collaboration with colleagues at the University of Maine and the University of Georgia. Baylor researchers will then use advanced statistics models to draw correlations that identify which compounds cause inhibitory effects and the degree to which those inhibitory byproducts actually restrict the fermenting process.

The study's approach will couple analytical capabilities with microarray and microtiter screening methods to assess the inhibitory effect of hydrolysates on cellulase enzymes and fermenting microorganisms. Multivariate statistics will be utilized to deduce complex correlations between analytical and biological data. It marks the first time this type of methodology has been used to make correlations between the data.

"If proven, this methodology could be applied in a much broader scope," Chambliss said. "It is expected that this approach will result in unique identification of the lignocellulosic degradation products responsible for observed inhibitory effects."

For more information, contact Dr. Chambliss at (254) 710-6849.

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