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"  By 2030 biofuels such as ethanol could replace up to one-third of the gasoline consumed in the U.S., according to the Department of Energy. Instead of burning irreplaceable fossil fuels, we&amp;#039;ll use reliable, renewable energy sources that are more environmentally benign. That&amp;#039;s the idea, anyway. In practice, integrating ethanol into gasoline has been a messy business. Critics claim ethanol additives are expensive for consumers, take too much corn out of the food supply, and provide environmental benefits that are marginal at best. In a new study in Science, researchers from the University of Wisconsin-Madison have begun to address the pricing issue by finding a way to efficiently remove sugars from wood and leftover cornstalks, or stover. Those energy-packed sugars can then be used to produce ethanol at a cost that&amp;#039;s 10 percent lower than the current method. Standard techniques produce ethanol from the starches in corn kernels. Not only could that cause food prices to go up but it also means that corn is specially cultivated to make ethanol\u2014and since growing corn is environmentally intensive, producing ethanol from corn grain may actually have a negative impact on the environment. For years scientists have been trying to find a way to derive ethanol from waste plant materials to avoid those problems, but extracting the sugars from inside the tough cellulose and lignin fibers has been a challenge, says Thomas Foust, a biomass expert with the National Renewable Energy Laboratory, who was not involved in the study. The new technique cuts costs by skipping one of the most expensive steps in ethanol production: using enzymes to break down tough plant material and release the valuable sugars. Enzymes can add 30 to 50 cents to the price of every gallon of ethanol. Instead of enzymes, the team used a chemical called gamma-valerolactone, or GVL. GVL is actually a biofuel itself, made from degraded biomass, but the researchers from the University of Wisconsin-Madison realized it was really good at disintegrating the tough cellulose and lignin fibers that trap a plant&amp;#039;s sugars. By taking ground-up bits of wood and corn stover and washing them repeatedly with a mixture of water and GVL, the team was able to extract up to 90 percent of the sugars. And the GVL can be reused again and again. &amp;quot;If you add a fairly simple additive like salt or liquid carbon dioxide, what happens is the GVL will spontaneously separate just like oil and vinegar in salad dressing,&amp;quot; says Jeremy Luterbacher, a postdoctoral researcher who led the project. &amp;quot;Then you&amp;#039;ve basically concentrated your sugars by five times, and you enable GVL to be recycled.&amp;quot; The resulting sugars can be fed to microbes to make ethanol or other biological products such as butanol, biodiesel precursors, and polyester precursors. The current laboratory setup only allows the researchers to produce about 20 milliliters of the sugar concentrate at a time. However, they estimate a biorefinery using this method could produce ethanol at a minimum price of $4.87, compared to current methods, which set the minimum at $5.13. The new technique looks to be competitive with current methods, Foust says. &amp;quot;Industry always wants options. In petroleum refining, there&amp;#039;s all kinds of variations in technology. We&amp;#039;d expect biofuels to be the same.&amp;quot; Next, Luterbacher&amp;#039;s group will be testing to see if the process is just as efficient at the 1-liter scale. If all goes well, they hope to build a full-scale pilot plant within a few years. "^^<http://www.w3.org/2001/XMLSchema#string>
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