USDA Researches Improved Ethanol Yield from Corn

PEORIA, Ill., Oct. 25--Cars in the 21st century could run on ethanol fermented from fiber-rich crop residues like wheat straw or corn stalks instead of corn. Agriculture Department scientists are moving in that direction with research that seeks to squeeze more ethanol from corn using the grain's fiber.

"This research delivers on the Clinton Administration's commitment to the continued growth and development of the domestic ethanol industry," said Agriculture Secretary Dan Glickman. "Technological innovations in corn production and ethanol conversion will continue to improve ethanol yield per bushel and per acre."

Microbiologist Rodney J. Bothast of USDA's Agricultural Research Service heads a research team that's now scaling up a process for converting grain fiber into sugars. Genetically engineered microbes convert these sugars into ethanol.

Modern ethanol plants ferment grain's starches and sugars to produce 2.5 gallons of ethanol per bushel of corn. Bothast's research team, based at the ARS National Center for Agricultural Utilization Research here, aims to coax an extra three-tenths of a gallon of ethanol from every bushel of corn kernels.

"This technology could be applied to converting cellulose from other crops creating additional income and market opportunities for farmers," said Glickman. "USDA analysis confirms that expanding ethanol production increases farm income and creates jobs in rural America."

In 1994, about 1.3 billion gallons of fuel ethanol were produced from corn. More than 60 percent came from wet milling, in which the corn is soaked in water before grinding it. Ethanol has traditionally been produced by fermenting the corn's starchy endosperm--the storage tissue in the seed that "feeds" the corn plant during germination. Currently the leftover fiber is mixed with water and fermentation residues, then dried and fed to animals.

"However, if this fiber were processed into ethanol, the increased efficiency and potential reductions in cost for a corn wet milling facility could significantly enhance net returns," says Robert B. Hespell, microbiologist and project leader for ethanol research in Bothast's Fermentation Biochemistry Research Unit here.

According to USDA's Economic Research Service, the ethanol energy now produced from each bushel of corn is more than 25 percent greater than the amount of energy used to grow and harvest the corn and distill it into ethanol, thanks to today's higher corn yields, more energy-efficient fertilizer production and improved distillation technology.

Recent research to further improve ethanol production is described in the October issue of Agricultural Research magazine, the monthly publication of the Agricultural Research Service.

Scientific contact: Rodney J. Bothast, National Center for Agricultural Utilization Research, Agricultural Research Service, USDA, Peoria, Ill. 61604. Telephone: (309) 681-6566