PEORIA, Ill. (AP) _ Molecular tinkering and genetic engineering may open the door to producing ethanol more cheaply and from a wider variety of material _ everything from corn cobs to potato peels.

Researchers at the Agriculture Department's Peoria laboratory are looking for ways to make ethanol more profitable and more competitive with gasoline.

In the short run, the research simply may improve efficiency for existing ethanol plants, said Rodney Bothast, head of the Fermentation Biochemistry Research Unit.

The first step probably will be making ethanol _ a form of alcohol that can be used as fuel _ from corn fiber that now is used as animal feed, he said. That would boost production by about 0.3 gallons for every bushel of corn _ a small change that could mean big money.

Scientists estimate an ethanol plant now making 100 million gallons a year would see annual income rise by $4 million to $8 million.

Corn fiber can be turned into ethanol now, Bothast noted, but it costs too much. Getting the cost down should be just a matter of finding new ways to chemically treat and process the corn.

``It's not a big jump from this to dealing with potato peels and stuff like that,'' said Robert Hespell, an ethanol researcher.

The researchers have more exotic tools as well.

Scientists can search for special enzymes to break down the plant matter so it can be fermented into alcohol. They can breed strains of bacteria, yeasts, even fungi to help in the process. What breeding does not accomplish, genetic engineering might.

Better efficiency will help quell one of the major criticisms of ethanol _ that it takes more energy to raise and process the corn than is derived from ethanol. Bothast said ethanol already produces about 25 percent more energy than it requires for production.

Big improvements are probably 15 or 20 years in the future, if research continues, Bothast said.

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DALLAS (AP) _ Five-pound sweet potatoes about the size of your arm might win a prize at the state fair, but they are scoring no points with farmers who depend on them for profit.

This year, a combination of drought followed by heavy rains produced a fast-growing potato that is too big for even a Texan's plate, and it's a nightmare for northeast Texas sweet potato farmers.

``It just makes you sick,'' said grower Bryan McCreight, who grew some of the largest sweet potatoes in the region this year.

While some of the orange potatoes weighed in at five pounds or more, producers said, shoppers like them smaller than two pounds and shaped like a fist for easier preparation.

The weather also cut the number of potatoes per hill, from five or six to one or two.

In Alba and Yantis, Wood County communities where production is centered, 60 percent or more of the crop could be left to rot in the fields.

McCreight and other farmers hoped the government would buy the potatoes and process them for school lunch or other food aid programs.

``See how pretty they are?'' McCreight asked, looking at one potato. ``Think about the people in Bangladesh starving. And there's nothing wrong with this potato. It's just crooked, large, misshaped. Tons and tons of potatoes.''