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United States Department of Agriculture

Agricultural Research Service


Location: Sustainable Biofuels and Co-Products

2010 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
Screening of lycopene-producing strains (UC Davis and ERRC) has been initiated using synthetic sugar solutions containing glucose, xylose, and arabinose, individually and using various compositions. The screening effort is still in progress but will be completed by the end of FY 2010. Once the screening is complete, we will begin testing using biomass hydrolysates.

Experiments on the effects of carbon dioxide sparging at various flow rates on succinic acid production by strain E coli AFP184 have been initiated and are still in progress. It is expected that the experiments will be completed early in FY 2011.

Coccolithophore cultures have been obtained from culture collections and stock cultures have been prepared. The identification of Coccolithophores and the appropriate growth conditions for subsequent studies has been initiated. Preliminary experiments have identified 3 promising candidates for further studies and others are continuing to be evaluated. Twenty liter cultivations will be done to prepare sufficient material for compositional analysis and will be complete by the end of FY 2010 or early in FY 2011.

Pilot scale experiments for corn germ oil recovery using a bubble column and aqueous enzymatic extraction pretreatment are being conducted. The recovered foam from the bubble column can be used to concentrate the free oil released; however, the pretreatment conditions used must not seriously degrade the foam stabilizing components. Experiments to improve the yield of free oil and the total oil in the foam are being investigated using germ cooking in combination with enzyme mixtures. Currently about 70% of the total oil is free oil and can be recovered in the foam. An additional 10% of the total oil is recovered in the foam; however, this is not free and requires further processing for recovery.

The extraction of constituents of agricultural residues, agricultural processing by-products and energy crops has been completed. Organic solvents (hexane, methylene chloride and ethanol) soluble components of corn Stover, rice straw, rice hull, sugar cane bagasse, switch grass and Miscanthus were extracted, dried and their percentage yields calculated. The water soluble components, starch, Hemicellulose A, Hemicellulose B, oligosaccharides, acid insoluble lignin, acid soluble lignin and cellulosic residue from corn Stover, rice hull, rice straw and Miscanthus were extracted, dried and their percent yields were calculated. The data collected from the fractionation studies will be used to help determine their value and commercial viabilities for coproduct production from biofuel facilities.

Review Publications
Yadav, M.P., Cooke, P.H., Johnston, D., Hicks, K.B. 2010. Importance of protein rich components in the emulsifying properties of corn fiber gum. Cereal Chemistry. 87(2):89-94.

Yadav, M.P., Parris, N., Johnston, D., Onwulata, C.I., Hicks, K.B. 2010. Corn fiber gum and milk protein conjugates with improved emulsion stability. Carbohydrate Polymers. 81:476-483.

Last Modified: 9/10/2014
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