WASHINGTON, D.C.—When gas prices were sky high, lots of people talked about ethanol as a fuel of the future. In particular, many investors placed their hopes in cellulosic ethanol. Such ethanol is made from the non-edible parts of corn, such as the stalk and leaves, or from non-corn sources such as certain kinds of grasses.* Unlike the ethanol available today, it does not require the edible parts—a requirement that has raised concerns of pitting fuel versus food.
But at least as important, no one has yet figured out a way to make cellulosic ethanol for anything approaching the price of gas—or how to make much of it at all. “Right now it’s just big diseconomies of scale,” says Aditya Rajagopalan, 17, a student at Choate Rosemary Hall in Connecticut.
Rajagopalan—one of 40 finalists in the Intel Science Talent Search here in Washington DC this week for the final judging rounds—hopes to change that. His Intel project looked at how different enzymes could be used to break down corn stover (the waste that’s left after a field of corn is harvested), which can then be turned into energy. Working for two summers at the Great Lakes Bioenergy Research Center at Michigan State University, he observed how various enzymes helped break down cellular structures in the stover, so that sugars could be extracted. Using these observations, he built mathematical models for a novel enzyme synergy model. By combining various enzymes in different quantities, his formulas show a way to reduce the use of high priced enzymes by 50 percent, while at the same time nearly doubling how much sugar is produced.
This four-fold increase in efficiency could certainly help close the gap between cellulosic and corn ethanol, or even, potentially, with fossil fuels. “There’s a lot of work to be done,” Rajagopalan says, and it’s not clear that cellulosic ethanol will be the fuel of the near future. But ultimately, he would like to be running an alternative energy company, perhaps one using this technology. “I figure it’s a good way to help the world,” he says.
ScientificAmerican.com is on hand to speak with several of the finalists in this prestigious national competition that is the modern incarnation of the old Westinghouse Science Talent Search, which began in the 1940s. The 40 finalists get scholarships ranging from $5,000 to the top prize of $100,000. You can read about past finalists in our "Where Are They Now" series, and follow along as we live-Twitter from Washington.
The sentence marked with an asterisk was changed to clarify the sources of cellulosic ethanol (March 10, 2009).
Photo of Aditya Rajagopalan by Laura Vanderkam/copyright Scientific American