Location: Sustainable Biofuels and Co-products Research
2016 Annual Report
Objectives
1. Develop processes to fractionate sorghum and corn/sorghum oils into new commercially-viable coproducts.
2. Develop processes to fractionate grain-derived brans into new commercially-viable coproducts.
2a: Develop processes to fractionate grain-derived brans into new commercially-viable coproducts such as lipid-based coproducts and for other industrial uses such as extrusion or producing energy or fuel.
2b: Develop commercially-viable, value-added carbohydrate based co-products from sorghum brans and the brans derived from other grains during their biorefinery process.
3. Develop processes to fractionate biorefinery-derived celluloses and hemicelluloses into new commercially-viable coproducts.
3a: Develop commercially-viable, value-added hemicellulose based co-products from sorghum biomass, sorghum bagasse and other agricultural based biomasses produced during their biorefining.
3b: Develop commercially-viable, value-added cellulose based co-products from sorghum biomass, sorghum bagasse and other agricultural based biomasses produced during their biorefining.
4. Develop technologies that enhance biodiesel quality so as to enable greater market supply and demand for biodiesel fuels and >B5 blends in particular.
4a: Improve the low temperature operability of biodiesel by chemical modification of the branched-chain fatty acids.
4b: Develop technologies that significantly reduce quality-related limitations to market growth of biodiesel produced from trap and float greases.
4c: Further develop direct (in situ) biodiesel production so as to enable its commercial deployment.
5. Develop technologies that enable the commercial production of new products and coproducts at lipid-based biorefineries.
5a: Enable the commercial production of alkyl-branched from agricultural products and food-wastes.
5b: Enable the commercial production of aryl-branched fatty acids produced from a combination of lipids and natural antimicrobials possessing phenol functionalities.
Approach
In conjunction with CRADA partners and other collaborators, develop technologies that identify new biorefinery coproducts, evaluate their applications and estimate their profitability and marketability. The approach will focus on development processes to produce several types of new coproducts. First, processes will be developed to extract and fractionate sorghum oil from sorghum kernels and sorghum bran. Processes will also be developed to extract and fractionated cellulose-rich and hemicellulose-rich fractions from sorghum kernels, sorghum bran, sorghum bagasse, and biomass sorghum. Other processes will be developed to improve the biofuel value of biodiesel by blending biodiesel with modified fatty acid derivatives to enhance its low temperature performance, reduce the levels of impurities that block fuel lines, economically convert trap grease and float grease to biodiesel, and improve the in situ process to make biodiesel directly from oil-rich low value agricultural products. In addition to biodiesel applications, other processes will be developed to produce branched fatty acids with unique functional (including improved lubricity) and biological properties (including antimicrobial and antioxidant properties).
Progress Report
Objective 1: The new HPLC (high performance liquid chromatography) method which we developed in the previous year has been further improved to analyze and compare sorghum waxes and other commercial waxes (carnauba wax, candelilla wax, sunflower wax, rice bran wax and beeswax). We have also used the new method to quantitatively analyze the levels of sorghum wax in sorghum oil obtained by solvent extraction and in distillers milo (sorghum) oil obtained from commercial sorghum ethanol plants. Because some corn ethanol plants also ferment blends of corn and sorghum, our method can be used to quantify the amount of sorghum wax in blends which contain both distillers corn oil and distillers milo oil.
Objective 2: We have continued to study the chemical properties of sorghum brans, obtained by decortication using a scarifier. We have found that the bran from sorghum contains compounds that are different than those from corn and other grains and we are in the process of identifying these compounds. These compounds can form problematic precipitates during both aqueous and organic solvent extraction so it is important that they be identified and evaluated for potential applications.
Objective 3: The proximate composition of the arabinoxylan and cellulose rich fractions isolated from sorghum bran was determined and the emulsifying and rheological properties of arabinoxylan were studied. The proximate composition of arabinoxylans isolated from sorghum biomass and sorghum bagasse was determined and their emulsifying and rheological properties were studied. The proximate composition of the cellulose rich fraction isolated from sorghum biomass and sorghum bagasse was determined. A manuscript on these results has been written and submitted to a journal for publication.
Objective 4: In collaboration with an ARS scientist from the National Center for Agricultural Utilization Research, introduction of esters with a bulky alkyl alcohol group (isopropyl, 2-butyl, and 2-ethylhexyl) to the “headgroup” of the skeletal unsaturated branched-chain fatty acid (iso-oleic) materials were investigated. These ester alcohols were chosen because of their bulky and branched-chain alkyl groups which can disrupt the crystal nucleation and growth mechanisms at low temperatures to reduce the melting point of these fats. These ester derivative fats are liquid at room temperature with enhanced fluidity. The results showed that these ester fats demonstrated improved cloud points (temperature where solid crystals become visible). The results also showed that they performed much better than the original parent fatty acids and saturated fats. This research demonstrated that the crystal structures can be significantly altered by simply chemically modifying the headgroup or tailgroup of esters. These findings are important as these iso-oleate ester fats can potentially replace solid fats which are often problematic at low temperatures. They can also potentially improve the cold flow properties in biodiesel when they are mixed with biodiesel, due to their capability to disrupt the crystal growth mechanism.
When biodiesel is produced from trap grease and float grease it often contains levels of sulfur that exceed the 15 ppm U.S. limits. Distillation by Wiped-Film Evaporation has been employed to fractionate the sulfur containing molecules into 3 primary temperature ranges that are designed to isolate low molecular weight and highly volatile impurities (low cut) from the high molecular weight and less volatile impurities (high cut). This process produces clean biodiesel in the middle cut that meets American Society for Testing and Materials (ASTM) specifications for all parameters except for sulfur concentration. To find economical and environmentally friendly ways to strategically remove the sulfur, those species must be identified. In collaboration with scientists from Drexel University, significant progress has been made in the quantification, isolation and identification of sulfur species in trap grease and float grease biodiesels by use of solid phase extraction, total sulfur analysis, and GC-MS.
The U.S. biodiesel industry currently generates about 2 billion gallons of biodiesel per year. The production goal by 2020 is 4 billion gallons per year. To make this a reality, additional feedstocks must be identified. While devoid of sugar, post-fermentation solids from sorghum and other grains contain up to 10% oil and is a potential feedstock for making biodiesel. Previous studies, primarily conducted by ARS scientists, have shown that the in-situ transesterification (I.S.T.) method can be used to make biodiesel from oil-bearing solids such as flaked soybeans and corn-derived DDGs. In this project, it has been proven that I.S.T. can be used to produce biodiesel from sorghum bran and sorghum distillers dried grains and solubles (DDGD). HPLC is used to quantify biodiesel yields and to quantify the amount of unreacted free fatty acids that remain in the reaction mixture.
Objective 5: To ensure accurate assessment of the potential utility of the isostearic acid products as biolubricants, the three byproducts (saturated linear-chain fatty acids, lactones, and dimer fatty acids) should be should be removed from the crude isostearic acid mixture. First, the mixture was recrystallized to remove the saturated acids (stearic and palmitic acids) at low temperature (-15 degrees C) in the presence of solvents. The recrystallized products were transferred to an additional funnel attached to a wiped film molecular distillation device. The products were slowly added to the evaporator to separate the dimer products. Although these two purification steps (recrystallization and distillation) can successfully remove the saturated acids and dimer acids, they are not sufficient to remove the lactones. Ongoing research efforts will be invested to reduce the lactones to an acceptable level.
ARS scientists developed a systematic regeneration technique for the spent zeolite to activate them so that one sample of zeolite can be used for many cycles of isomerization reaction to produce isostearic acid. This invented method will help to reduce the overall cost of this technology when it will be used in the commercial scale production. With this method, we mainly use heat treatment to activate the fresh zeolite and regenerate the spent zeolites instead of doing acid treatment which generates an abundance of acid waste which is costly to handle at industrial scale. It has been found that after using in 10 cycles of isomerization reaction, the zeolite catalyst is still capable of yielding high selectivity of isostearic acid.
Phenolic branched-chain lipids made from the ARS technology are a complex mixture of products. Therefore, it is important to develop methodology to purify the products efficiently in order to determine their effectiveness in killing bacteria. A highly efficient wiped film distillation technique has been developed to distill the products. The results showed that up to 95% purity of these phenolic branched-chain lipids could be obtained. Most importantly, regardless of which phenolics (i.e., thymol, carvacrol, and creosote which have strong antimicrobial properties, which all posses unpleasant characteristic odors) after coupling onto the fatty acids, these compounds which mimic the existing phenolics no longer have the unpleasant odors. Using this distillation technique, a significant amount of products can be obtained which have been evaluated as antimicrobial agents. The preliminary results show that the phenolic branched-chain lipids have potential to kill bacteria.
Accomplishments
1. Development of the first successful HPLC method to analyze sorghum wax and commercial waxes. ARS researchers in Wyndmoor, Pennsylvania developed a new HPLC (high performance liquid chromatography) method to quantitatively analyze sorghum wax. This new method is valuable because it provides an accurate method to quantify sorghum wax in sorghum oil, distillers milo oil, and in sorghum grain processing fractions such as bran and distillers dried grains and solubles (DDGS). It will also be very useful for the analysis of commercial waxes such as carnauba wax, candelilla wax, sunflower wax, rice bran wax and beeswax. It is the first successful HPLC method for waxes. Gas chromatography has traditionally been used for analysis of waxes but it has drawbacks and inaccuracies because it uses very high temperatures and the wax components can break down during analysis. This new method employs an evaporative light scattering detector for quantification and LC-mass spectrometry for chemical structural analysis. Previous attempts to develop HPLC methods for waxes have mainly focused on C8 and C18 HPLC columns, but this new method uses a C30 column and uses methanol and chloroform as solvents, which are the best solvents to solubilize all of the wax components. It is anticipated that this new method will become widely used for commercial wax analysis.
None.
Review Publications
Moreau, R.A., Harron, A.F., Powell, M.J., Hoyt, J.L. 2016. A comparison of the levels of oil, carotenoids, and lipolytic enzyme activities in modern lines and hybrids of grain sorghum. Journal of the American Oil Chemists' Society. 93:569-573.
Lehtonen, M., Teraslahti, S., Xu, C., Yadav, M.P., Lampi, A., Mikkonen, K.S. 2016. Spruce galactoglucomannans inhibit the lipid oxidation in rapeseed oil-in-water emulsions. Food Hydrocolloids Journal. 58:255-266.
Berlanga-Reyes, C., Carvajal-Millan, E., Hicks, K.B., Yadav, M.P., Rasconchu, A., Lizardi-Mendoza, J., Islas-Rubio, A.R. 2014. Protein/Arabinoxylans Gels: Effect of mass ratio on the rheological, microstructural and diffusional characteristics. International Journal of Molecular Sciences. 15:19106-19118.
Cirre, J., Al-Assaf, S., Phillips, G.O., Yadav, M.P., Hicks, K.B. 2013. Improved emulsification performance of corn fiber gum following maturation treatment. Food Hydrocolloids, 35:122-128.
Zhang, F., Luan, T., Kang, D., Zhang, H., Yadav, M.P. 2014. Viscofying properties of corn fiber gum with various polysaccharides. Food Hydrocolloids Journal. 43:218-227.
Samala, A., Srinivasan, R., Yadav, M.P. 2014. Comparison of Xylo-oligosaccharides production by autohydrolysis of fibers separated from ground corn flour and DDGS. Journal of Food and Bioproducts Processing. 94:354-364.
Qiu, S., Yadav, M.P., Chen, H., Liu, Y., Tatsumi, E., Yin, L. 2014. Effects of corn fiber gum (CFG) on the pasting and thermal behaviors of maize starch. Carbohydrate Polymers. 115:246-252.
Moreau, R.A., Fang, X. 2016. Analysis of alkylresorcinols in wheat germ oil and barley germ oil via HPLC and flourescence detection: Cochromatography with tocols. Cereal Chemistry. 93(3):293-298.
Qiu, S., Yadav, M.P., Tatsumi, E., Yin, L. 2015. Effects of corn fiber gum with different molecular weights on the gelatinization behaviors of corn and wheat starch. Food Hydrocolloids Journal. 53:180-186.
Fang, X., Moreau, R.A. 2014. Extraction and demulsification of oil from wheat germ, barley germ, and rice bran using an aqueous enzymatic method. Journal of the American Oil Chemists' Society. 91:1261-1268.
Yadav, M.P., Hicks, K.B. 2015. Isolation of barley hulls and straws constituents and study of emulsifying properties of their arabinoxylans. Carbohydrate Polymers. 132:529-536.
Lin, X., Ma, L., Moreau, R.A., Ostlund, Jr, R.E. 2011. Glycosidic bond cleavage is not required for phytosteryl glycoside-induced reduction of cholesterol absorption in mice. Lipids Journal. 46:701-708.
Lew, H.N., Yee, W.C., Mcaloon, A.J., Haas, M.J. 2014. Techno-economic analysis of an improved process for producing saturated branched-chain fatty acids. Journal of Agricultural Science. 6(10):158-168.
Wyatt, V.T. 2012. Effects of swelling on the viscoelastic properties of polyester films made from glycerol and glutaric acid. Journal of Applied Polymer Science. 126:1784-1793.
Wyatt, V.T., Yadav, M.P. 2013. A multivariant study of the absorption properties of poly(glutaric-acid-glycerol) films. Journal of Applied Polymer Science. 130(1):70-77.
Kokubun, S., Yadav, M.P., Moreau, R.A., Williams, P.A. 2014. Components responsible for the emulsification properties of corn fibre gum. Food Hydrocolloids Journal. 41:164-168.
Rogowski, A., Briggs, J.A., Mortimer, J.C., Tryfona, T., Terrapon, N., Lowe, E.C., Basle, A., Day, A.M., Zheng, H., Rogers, T.E., Yadav, M.P., Henrissat, B., Martens, E.C., Dupree, P., Gilbert, H.J., Bolam, D.N. 2015. Glycan complexity dictates microbial resource allocation in the large intestine. Nature Communications. 6:1-15. doi: 10.1038/ncomms8481.
Lew, H.N., Hoh, E., Foglia, T. 2012. Improved synthesis and characterization of saturated branched-chain fatty acid isomers. European Journal of Science and Lipid Technology. 114:213-221.
