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United States Department of Agriculture

Agricultural Research Service

Research Project: Value Added Coproducts for Improving the Economics and Greenhouse Gas Emissions of Corn and Cellulosic Fuel Ethanol Production

Location: Sustainable Biofuels and Co-Products

2013 Annual Report


1a.Objectives (from AD-416):
1: Develop technologies that enable commercially-viable* processes for producing new, valuable coproducts from DDGS, thin stillage, pentoses, CO2 or other byproducts of ethanol biorefining.

2: Develop technologies that enable new, commercially-viable* processes to produce food-grade corn oil, proteins, phytochemicals or other high-value coproducts from ethanol biorefineries.

3: Develop fractionation, enzymatic and/or chemical technologies that enable commercially-viable, high-value, non-fermentation hemicellulose- and cellulose-based coproducts from lignocellulosics.

* Potential commercial-viability will be regularly assessed with assistance from ONP, OTT and/or industrial partners.


1b.Approach (from AD-416):
Technologies will be developed that produce valuable coproducts from low value biorefining byproducts using innovative microbiologic, enzymatic and chemical processing strategies. Carbon dioxide from fuel ethanol facilities, currently vented or compressed for uses that eventually return it to the atmosphere, will be biologically incorporated into stable, industrially important chemical compounds using microalgae and other CO2 utilizing microorganisms. Commercially viable processes for removing food-grade oils, proteins, phytochemicals or other high value components from biorefinery feedstock fractions will be developed by innovative aqueous-enzymatic extraction and other novel technologies. Functional hemicellulose and cellulose-based products will be extracted from ligno-cellulosic feedstocks for use in foods and industrial products using enzymatic and chemical processing technologies. The successful development of these technologies will result in improved energy and environmental properties for biofuels, the potential sequestration of carbon into useful feeds and chemicals and an increased economic competitiveness of the US biofuels industry from the sale of new higher value coproducts.


3.Progress Report:
Continued to improve the yields and reduce the cost of our aqueous enzymatic oil extraction process to extract corn oil from corn germ. There is interest in using this process to extract corn oil from corn germ that is removed in dry grind ethanol plants before fermentation to product fuel ethanol. We are in the process of writing a research paper and an invention report for the process.

We have continued to improve our process to hydrolyze and fractionate ferulic acid from various types of biomass, including corn fiber and corn processing byproducts.

A complete molecular characterization of crude corn fiber gum prepared at different pH, ultra filtered (semipure) and ethanol precipitated (pure) was done. Molecular characterization of crude and pure arabinoxylan isolated from oat bran and pure arabinoxylans from corn bran, corn stover, rice fiber, wheat bran, wheat straw, switch grass, Miscanthus, sugarcane bagasse and three varieties of sorghum was also accomplished. Hemicellulose A and B from all above biomasses were isolated and their proximate composition was determined. The carbohydrate composition, dietary fiber content, Oxygen Radical Absorbance Capacity (ORAC) values and emulsion stabilities of Hemicellulose B from all above sources was determined. The study of Corn Fiber Gum (CFG) for its ability to encapsulate oil and bind charcoal to form briquette was also done. The water holding capacity of the alkali insoluble cellulose rich fraction from several biomasses was studied.

Optimal conditions for soaking in aqueous ammonia (SAA) pretreatment of corn fiber and DDGS were established. Corn fiber and Distillers Dried Grains with Solubles were pretreated using these optimal conditions. The pretreated materials were subjected to enzymatic hydrolysis by ACCELLERASE 1500. The hydrolysates containing glucose and xylose were used for production of succinic acid using E. coli AFP184 in bench-scale fermentors.


4.Accomplishments
1. New bio-based products help lower the cost for making cellulosic biofuels. ARS researchers at Wyndmoor, Pennsylvania have developed a novel way (patent pending) to make cellulosic biofuels cheaper, by co-producing valuable bio-based products during biofuels production. The new products called “hemicelluloses” were produced for the first time when fuel ethanol was made in the laboratory from 9 different types of non-food biomass feedstocks including sorghum bran, corn stover, switch grass, giant miscanthus, barley straw, wheat straw, wheat bran, rice bran, and sugar cane waste. The hemicellulose products from each feedstock were found to have valuable functional properties including the ability to: emulsify oils in water, be powerful antioxidants, serve as dietary fiber, act as bio-based glues, and serve as functional ingredients in other food and non-food products. The production and sale of these valuable coproducts by cellulosic biofuels producers will bring new sales revenue and thus, reduce the overall price for cellulosic biofuels, making them more affordable.

2. Development of an improved method for obtaining valuable corn oil from fuel ethanol production. Because corn grain used to make fuel ethanol and animal feeds is expensive, the nation’s 200+ fuel ethanol producers are struggling to be profitable. During fuel ethanol production, corn oil is often recovered as a value-added coproduct but only in low yields of about 25% of the total oil present. ARS researchers at Wyndmoor, Pennsylvania have now improved the process by adding a novel (patent pending) mixture of enzymes into a laboratory scale fuel ethanol production process. Not only did this improve corn oil yields to more than 40%, it also significantly reduced the amount of water, energy, and corn used in the ethanol process. Ethanol producers now can use this process to improve profitability while further improving the environmental footprint of fuel ethanol.


Last Modified: 7/22/2014
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