From corn fiber to consumer products—New process captures valuable components
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May 12, 2003--Increasing the high-value yield from crops is an ongoing challenge for the nation's farmers, agricultural processors, and the bioproducts industry. This is particularly true for corn, which the United States produces at the rate of 9.2 billion bushels annually. Of that crop, approximately 1.4 billion bushels are purchased by the wet milling industry for processing primarily into starch, oil, corn gluten feed, and corn gluten meal. The starch is used for industrial and food applications including high fructose corn syrup and ethanol. The oil is used in food applications, and the corn gluten feed and meal generally are sold as animal feed.
Corn gluten feed is the lowest value item in the product stream, typically selling for only $0.04 to $0.05 per pound and competing directly with corn in the animal feed market. This low-priced product accounts for approximately 27 percent of the corn that enters a wet mill and contains approximately 70 to 80 percent fiber. Conversion of the corn fiber to value-added products would greatly enhance the value of the nation's corn crop on several fronts.
The National Corn Growers Association (NCGA), representing growers, and the Archer Daniels Midland Company (ADM), representing processors, have formed a partnership in an effort to divert corn fiber from the feed market and direct it to industrial product markets. In addition, corn fiber is a low-cost, carbohydrate-rich, readily available feedstock that could potentially reduce the use of imported petroleum for production of ethanol and other industrial chemicals. For this reason, the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy is sponsoring a Cooperative Research and Development Agreement through which NCGA and ADM have access to staff and equipment at the Pacific Northwest National Laboratory (PNNL).
The NCGA coordinates the cooperative research effort. ADM defines the principal objectives of the engineering effort, conducting process development performing final product analyses, and assessing commercial viability of possible process options. PNNL is involved in the collaborative process development efforts along with ADM, and also provides key enabling analytical instrumentation and unique technology in the fields of organic synthesis and chemical catalysis.
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The three organizations have formed a multi-disciplinary scientific research and engineering team and in just two years conducted work in the laboratory that defines a new process for economical recovery of several valuable components from the corn fiber. Results to date are very encouraging, and the NCGA, ADM, and DOE have agreed to undertake a second phase of the project, intended to complete development of the process and demonstrate its viability at a pilot scale. Upon successful completion of this second phase, the NCGA and ADM will cooperate to deploy the process commercially.
Extracting value from each component
The corn fiber stream is a complex mixture of components, some of which are sensitive to process conditions. The project team has combined applied and fundamental sciences with advanced process engineering to take a holistic approach, in which the fiber stream is fractionated into its primary components (carbohydrates, oils protein) and each fraction is recovered in a manner that enables maximum economic utilization of that fraction.
The carbohydrate fraction yields five- and six-carbon sugars, primarily glucose, xylose, and arabinose. These sugars are the most abundant chemical building blocks in the fiber. The glucose will be used to make fuel ethanol, a product that currently reduces U.S. oil import requirements by almost 2 billion gallons annually. Through the new process, ethanol could be produced in sufficient quantity to help achieve the U.S. government objective of tripling U.S. ethanol capacity by 2020.
The other sugars can be catalytically converted to propylene glycol and ethylene glycol, chemicals that are used in industrial and consumer products, including plastics, polyesters, and antifreeze. Currently produced from through petrochemical feedstocks, these chemicals have sizeable U.S. markets. Producing them from sugars could support U.S. policy interests by further reducing petroleum imports.
The process also preserves the functionality of the small, but potentially high-value, oil fraction. Of key interest is the recovery of trace phytosterols that have high-value applications as "nutraceutical" food supplements and as "botanical oils" in many personal care products. There is a limited supply of these oil components, and their recovery will help keep pace with consumer demand and contribute significantly to the economic viability of the process.
The recovery of the carbohydrate and oil fractions captures approximately 60 percent of the corn fiber volume for industrial applications. The residual 40 percent is a very high protein mixture, about double the protein content in less than half the bulk compared to the original product, and should deliver a higher feed value in the marketplace.
Science delivers solutions
Corn fiber contains about 3 percent oil, with 5 to 20 percent of that oil consisting of phytosterols. Because of the potential value of these trace components, it was essential that analysis of the oil be extremely accurate and reliable and that the functionality of the molecules be retained throughout the recovery process.
The first step was crucial: determining the exact composition of the oil fraction. Four months into the project, highly sensitive methods developed at PNNL showed that certain trace components were present and others were not. Researchers promptly focused their efforts on the recovery of components that were confirmed present in the oil.
The precise and timely analysis was made possible by the DOE Office of Science's Environmental Molecular Sciences Laboratory's extraordinary collection of scientific instrumentation, including the Western Hemisphere's most comprehensive array of nuclear magnetic resonance (NMR) spectrometers. These spectrometers are similar to hospital magnetic resonance imaging devices and contain high-field superconducting magnets for the study of molecules and cells. They enable researchers to determine the most fundamental information about molecular structure in support of studies of cellular mechanisms, materials science and chemical processes-including the composition of corn fiber and its trace oils.
NMR analysis produced highly sophisticated identification of the corn fiber oil constituents. Researchers then used another technology, gas chromatographic mass spectrometry, to determine the quantities present of each fraction. Information obtained from these investigations enabled development of a process for recovery of intact phytosterols. The same NMR instruments also proved invaluable in providing microkenetic analyses used to identify the optimum process conditions for recovery and conversion of the carbohydrate fraction. The result: a financially attractive "disassembly" process that enables optimal recovery of trace oil components and significant amounts of sugars.
Making the numbers work
Process economics are critical to the ultimate fate of the process. Laboratory results are being used to perform process engineering and economic evaluations, and that information is continually applied to direct further research and process development.
Early laboratory results have yielded promising financial assessments. The next step is to evaluate several elements of the new process on the pilot scale to determine the process' prospects for commercial success. The pilot phase will begin in 2003 and will take place over 2.5 years. It will include bench-scale process optimization testing, system design, system procurement and fabrication, system assembly, shakedown testing, actual testing, and an economic evaluation of the integrated process. The commercial parties (ADM and NCGA) are leading this phase of process development. DOE will continue to provide technical and analytical support through PNNL.
There is a lot at stake. The new technology could significantly improve supplies of valuable industrial chemicals and transportation fuels, an important goal for the government. At the same time, diverting this fiber from the feed market could improve the value of corn purchased for grind and support the overall value of feed grains, directly benefiting farmers and processors.--by Rick Orth, Charles Abbas, and Rene Shunk
Media contact: Geoff Harvey, senior communications specialist, (509) 372-6083, Geoffrey.Harvey@pnl.gov
Technical contact: Rick Orth, PNNL Senior Scientist, (509) 375-6709, rick.orth@pnl.gov
Related Web Links
DOE Grant Moves Forward Research Into New Markets for Corn (12-09-02)
Franz, JA, et al. "Detection of Sterol, Stanol, Lipid and Carbohydrate Components in Corn Fiber Products. 13C and 1H NMR and Chromatographic Methods." Poster Presentation 1A-24 of the 25th Symposium on Biotechnology for Fuels and Chemicals, May 5, 2003)
NCGA Looks to Improve Corn Market with New Partnership (12-12-02)
NCGA Research Victory Tops First Quarter Accomplishments (1-17-03)
Funding: The U.S. Department of Energy Office of Energy Efficiency and Renewable Energy is sponsoring a Cooperative Research and Development Agreement through which the National Corn Growers Association and Archer Daniels Midland Company have access to staff and equipment at the DOE Office of Science's Pacific Northwest National Laboratory and Environmental Molecuar Sciences Laboratory.
The Pacific Northwest National Laboratory is a DOE Office of Science research facility that delivers breakthrough science and technology in the areas of environment, energy, health, fundamental sciences and national security. Battelle, based in Columbus, Ohio, has operated the laboratory for DOE since 1965.
The William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) is the DOE Office of Science's newest national scientific user facility, located at the Pacific Northwest National Laboratory in Richland, Washington. It is operated by PNNL for the DOE's Office of Biological and Environmental Research. EMSL houses 12 nuclear magnetic resonance spectrometers ranging from 300 to 900 MHz as well as other complementary instrumentation. The resident research staff offers their expertise in the areas of structural biology, solid-state materials/catalyst characterization, magnetic resonance imaging techniques, and high-resolution spectroscopy of biological objects.
The National Corn Growers Association is a national organization founded in 1957 and represents more than 32,300 dues-paying corn growers from 48 states and the interests of more than 300,000 farmers who contribute to corn checkoff programs in 20 states. It is a federation of state organizations, corn boards, councils and commissions developing and implementing programs and policies on a state and national level to help protect and advance the corn producer's interests.
With a worldwide transportation network and more than 268 domestic and international plants, Archer Daniels Midland Company is uniquely positioned to efficiently provide food, animal feed, and industrial materials that improve the quality of life around the globe.
Authors: Rick Orth is a senior scientist at the Pacific Northwest National Laboratory. Charles Abbas is a project coordinator at Archer Daniels Midland Company. Rene Shunk is director of research and business development at the National Corn Growers Association.
Reprinted with permission from Resource Magazine, published by ASAE, The Society for Engineering in Agricultural, Food, and Biological Systems. The article appeared in the March 2003 edition.