Opening new markets for agricultural byproducts

Researchers at Pacific Northwest and ADM have developed processes that will reclaim greater value from the hulls of corn kernals by separating the hull's fiber into its basic components—lipids, carbohydrates, proteins. These products will then be used to produce fuel ethanol and the building blocks for industrial chemicals, as well as higher value food, feed and consumer products.

Each year the U.S. corn milling industry generates almost 14 billion pounds of fiber as hulls are removed so that the starch, protein and vegetable oil within the corn kernels can be processed. Cattle feed is the primary use for this fiber byproduct and is typically the lowest value product of corn milling.

But new processes developed through a Cooperative Research and Development Agreement between Pacific Northwest National Laboratory, the National Corn Growers Association and food processor Archer Daniels Midland (ADM) are expected to change all that. Researchers at Pacific Northwest and ADM have developed processes that will reclaim greater value from this resource by separating the corn fiber into its basic components—lipids, carbohydrates, proteins. These products will then be used to produce fuel ethanol and the building blocks for industrial chemicals, as well as higher value food, feed and consumer products. "We're taking something that had very low market value and opening up lucrative new markets for it, while also creating new supplies for existing, higher-margin markets," said Todd Werpy, program manager for Pacific Northwest's Environmental Technology Directorate.

Working together, the research teams have developed a financially attractive process that enables optimal extraction of specialty lipids and significant amounts of sugars. "In essence, we've developed an economically attractive disassembly process to get out what we knew was in the fiber, but couldn't be recovered cost-effectively in the past," Werpy said.

By separating the lipids from the fiber that comes off the kernel, trace amounts of sterols can be extracted using the new process. Although small in volume, the sterols have high-value applications as food supplements and in many consumer products, including cosmetics, shampoo and other personal care products. While the market for sterols is not a new one, there has been limited supply and this process will help keep pace with consumer demand.

The carbohydrate portion of the hull—what was previously sold only as cattle feed—yields various sugars, most of which can be chemically converted to propylene glycol and ethylene glycol, compounds used in industrial and consumer products, including plastics, polyesters and antifreeze. These chemicals create substantial value and have significant global markets. The remaining sugar will be used to make fuel ethanol, a high-value product that reduces U.S. oil import requirements by almost 2 billion gallons every year.

"We believe this process can be financially successful on a commercial scale," Werpy said, speaking for the ADM, Corn Growers and Pacific Northwest team. Benefits include opening new markets for grain processors, making corn a more profitable crop for farmers and reducing U.S. needs for petroleum, since this new supply of ethanol will replace petroleum-derived fuels and chemicals.

Researchers also envision comparable uses for low-value byproduct streams produced by other segments of agribusiness, such as wheat and rice milling, oil seed crushing and dairy processing.

The Laboratory, ADM and National Corn Growers will define an optimal, integrated process in 2002. Depending on the results of this work and availability of funds, the team hopes to test the complete process at pilot scale during the following two years, with full-scale commercial implementation anticipated soon after.