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New Technology to Transform Harvest Waste into Ethanol, Plastic

November 15, 2004

By George C. Ford

Source: Cedar Rapids Gazette

 

A biotechnology breakthrough has the potential to transform the harvested corn and wheat fields of the Great Plains into the equivalent of the oil fields of the Middle East.

Scientists at Genencor International in Palo Alto, Calif., and the Department of Energy's National Renewable Energy Laboratory have reduced the costs of enzymes needed to make commercially viable ethanol from agricultural waste. The latter includes corn stalks, wheat straw and other forms of biomass remaining after each harvest.

Ethanol is currently made from sugar cane and starchy grains, typically corn. Ethanol manufacturing plants have sprung up throughout the Midwest in recent years as the United States has moved to decrease its dependence on foreign oil.

Tom Pekich, Genencor group vice president, bioproducts, said a hydrolysis step is needed to break down the biomass so it could be used as a feedstock for the fermentation process involved in making ethanol.

"We were asked four years ago to come up with cellulosic enzymes that would reduce the hydrolysis cost significantly," Pekich said. "We received some grants from the National RenewableEnergy Laboratory and have been able to demonstrate a 30-fold improvement in the enzyme cost."

Genencor, which operates a bioproducts plant in southwest Cedar Rapids, selected corn stalks because of the ease of obtaining it and the abundance available in states such as Iowa. The company opened its first full-scale bioproducts plant in Cedar Rapids in 1991 because of the abundant supply of corn for the fermentation process.

"Work continues to make the enzyme cost about 8 cents to 10 cents per gallon of ethanol," Pekich said. "Right now, the cost is down to between 10 cents and 20 cents per gallon."

Pekich said Genencor, the Department of Energy and other parties are assessing the costs of collecting the corn stalks, storing them, pretreating them, the hydrolysis process and the fermentation process. He said a pilot plant will likely be built within the next couple of years to demonstrate the commercial viability of the technology.

In addition to its work on ethanol, Pekich said Genencor is working with Cargill Dow LLC of Minnetonka, Minn. to use the same biomass process to produce chemicals needed to manufacture plastic.

"Cargill Dow has a process that produces a biopolymer from polylactic acid," he said. "We're working on utilizing the technology we've been using for biomass and integrate that into a process to make lower-cost polylactic acid.

"If you can take a biomass and convert it to a low-cost feedstock for the fermentation process to make ethanol, you can make other chemicals from it."

Pekich believes "biorefineries" will exist in the very near future that will produce an array of fuels and chemicals from biomass.

"Instead of making fuels and chemicals from non-renewable sources like oil and petroleum, we will be making them from renewable cellulosic sources like corn (stalks), wheat straw and wood," he said. "We're opening up a whole new avenue in making the materials of the future that will have so much less impact on the environment."