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PRI's Environmental News Magazine

Ethanol By-Products

Air Date: Week of September 29, 2000

Ethanol is the active ingredient in booze, but it can also make cars and trucks go. So, for years ethanol made from corn has been touted as a renewable alternative to gasoline. More people are using it in their vehicles, but gasohol still relies on a heavy government subsidy to remain competitive. But now ethanol is finding another, and potentially profitable, use. Jonathan Ahl of the Great Lakes Radio Consortium reports.

Transcript

CURWOOD: Ethanol is the active ingredient in booze, but it can also make cars and trucks go. So, for years ethanol made from corn has been touted as a renewable alternative to gasoline. More people are using it in their vehicles, but gasohol still relies on a heavy government subsidy to remain competitive. But now ethanol is finding another, and potentially profitable, use. Jonathan Ahl of the Great Lakes Radio Consortium reports.

(Spinning)

AHL: Several massive iron cylinders spin around in a barn-sized building at Williams Bioenergy in Pekin, Illinois. The machines are drying a fluffy substance made from the shavings of corn kernels. The same stuff that gets stuck between your teeth when you eat popcorn. Williams’ Business Development Officer Jack Huggins says the plant makes tons of this fibrous ethanol byproduct each year and sends it overseas.

HUGGINS: And in Europe, they blend it into their animal feed rations, so we get back somewhere between $50 and $60 a ton right now.

AHL: That barely pays for the shipping, and it's one of the reasons why making a profit on ethanol is difficult right now. But that could soon change.

(Grinding)

AHL: At the U.S. Department of Agriculture lab in Peoria, Illinois, researchers are using a household coffee grinder to mince the corn kernel shavings into a fine fluff. This is the first step in extracting a sweetener called xylitol from the fiber, which contains two sugars: glucose and xylose. Dr. Tim Leathers says all it takes to change xylose to xylitol is to add a special kind of yeast. But there's a problem: the yeast would rather eat the glucose, like it's supposed to, but by then it's too full to react with the xylose.

LEATHERS: To address this problem, we've developed a two-stage fermentation, in which an initial set of yeast strains is used to consume the glucose. Then those cells are removed and the second team of yeast is introduced that now more efficiently converts the xylose to produce xylitol.

AHL: Xylitol can sweeten candy, gum, and mouthwash. It tastes like sugar. It's safe for diabetics. It doesn't cause tooth decay. And it sells for about 100 times more than the ethanol byproduct it's made from. That's gotten the attention of ethanol producers. Bob Scott is a professor of economics at Bradley University. He says making ethanol byproducts like xylitol could make up for the low profit margin on the corn-based fuel.

SCOTT: If the price of corn were too high, or the price of gasoline were too low, then ethanol wasn't economically as advantageous. But when there are these other products that could be made from the same corn while ethanol is being made, it takes some of the weight off ethanol, makes it a healthier product economically.

AHL: Making xylitol from corn may also have environmental benefits. Currently, xylitol is manufactured by adding harsh chemicals to birch tree bark at high temperatures. Larry Cunningham is a Vice President at agribusiness giant Archer Daniels Midland. He says his company is always looking for more natural ways to produce food products.

CUNNINGHAM: I think that's got to be a much more efficient, and at the end of the day, environmentally friendly way to go about it than taking down forests of birch trees.

AHL: The USDA has not yet convinced companies to invest staff and equipment to make xylitol. Ethanol producers, meanwhile, may have to develop several other profitable byproducts to make the corn-based fuel a strong economic alternative to gasoline. For Living on Earth, I'm Jonathan Ahl in Peoria, Illinois.

 

 

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