Location: Sustainable Biofuels and Co-products Research
2017 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
Progress was made on all objectives, all of which fall under National Program 213 – Biorefining, Component 1 Biochemical Conversion. Addressing Problem Statement 2. Technologies that reduce risks and increase profitability in existing industrial biorefineries. Component 2 (Biodiesel) addressing Problem Statement 2.1, to improve the engine performance of biodiesel, and Problem Statement 2.2, development of new technologies that reduce risks and increase profitability in existing industrial biorefineries for converting lipids.
Objective 1: Distillers Milo Oil and blends of Distillers Corn Oil/Distillers Milo Oil were obtained from industrial sources. We developed a countercurrent method with ethanol that allowed us to fractionate these oils into two fractions, one is sorghum wax and the other is a mixture of other conventional oil components (triglycerides, free fatty acids, and sterols). Using our new HPLC-MS analytical method, the wax fraction was shown to have a purity of 80-90%. We have begun to conduct experiments to extract and fractionate sorghum oil and sorghum wax with supercritical CO2.
Objective 2: Samples of several sorghum brans were analyzed for protein and other water soluble components. The major water soluble component was protein, at a level of about 6.5%.
The sugar composition (relative mole %) of the arabinoxylan (AX) from sorghum bran was mainly xylose (42%) and arabinose (35%), with less than 10% each of glucuronic acid, glucose, galactose, and galacturonic acid. Its molecular characterization was completed and the manuscript is in preparation. Its emulsion stability was characterized and published. The results indicate that the arabinoxylan from sorghum bran is similar, but not identical to, the well-characterized arabinoxylans of corn and other grains.
The sugar composition (relative mole %) of Cellulose-Rich Fraction (CRF) from sorghum bran was glucose (55%), arabinose (23%), xylose (17%), and galactose (6%). The glycosyl linkage composition of CRF from sorghum bran was predominately 1, 4 linked glucose (66%) and less than 10% each of 11 other linkages. Its water binding properties were characterized and the results were published. The composition and linkages of the Cellulose-Rich Fraction from sorghum bran indicate that it is a unique carbohydrate polymer with more of the properties of cellulose (55% glucose) than of hemicellulose (40% arabinose + xylose).
Objective 3: The sugar composition (relative mole %) of the arabinoxylan (AX) from sorghum bagasse was xylose (58%), arabinose (18%), and less than 10% each of glucose, galactose, galacturonic acid, and glucuronic acid. The results indicate that the composition of the arabinoxylan from sorghum bagasse is similar, but not identical to, the well-characterized arabinoxylans of corn and other grains.
The sugar composition (relative mole %) of the arabinoxylan (AX) from biomass sorghum was xylose (64%), arabinose (17%), and less than 10% each of glucose, galactose, galacturonic acid, and glucuronic acid. Their molecular characterization was completed and the manuscript is in preparation. Their emulsion stability was studied and the results are published. The results indicate that the composition of the arabinoxylan from biomass sorghum is similar, but not identical to, the well-characterized arabinoxylans of corn and other grains.
The sugar composition (relative mole %) of Cellulose-Rich Fraction (CRF) from sorghum bagasse was xylose (51%), glucose (39%), and less than 10% each of arabinose and galactose. The predominant glycosyl linkages of CRF from sorghum bagasse were 1, 4 linked glucose (69%) and 1, 4 linked xylose (22%) and less than 10% each of 10 other linkages. The composition and linkages of the Cellulose-Rich Fraction from sorghum bagasse indicate that it is a unique carbohydrate polymer with more of the hemicellulose (60% arabinose + xylose) properties than of cellulose (39% glucose) properties.
The sugar composition (relative mole %) of Cellulose-Rich Fraction (CRF) from biomass sorghum was glucose (53%), xylose (38%), and less than 10% each of and arabinose and galactose. The glycosyl linkage of CRF from biomass sorghum was predominantly 1, 4 linked glucose (64%), 1, 4 linked xylose (27%), and less than 10% each of six other linkages. The composition and linkages of the Cellulose-Rich Fraction from biomass sorghum indicate that it is a unique carbohydrate polymer with about half of the properties of cellulose (53% glucose) and half of the properties of hemicellulose (45% arabinose + xylose).
Objective 4: We have continued to develop new methods to synthesize and purify a group of iso-oleic acid derivatives for use as fuel additives. We found that the first step in making the iso-oleic acid at the large scale level is achievable. The reaction conditions gave high yields of the desired products and high conversions of the starting fatty acids. The next step in making the ester derivatives from iso-oleic acid is currently being evaluated. Once the ester products are made, they will be sent to collaborators to evaluate as fuel additives.
We have developed two strategies to remove sulfur species from biodiesel made from trap grease and waste water treatment scum. Distillation protocols have been developed that lower the concentration of sulfur-bearing species in biodiesel below the industry mandated 15 PPM in some samples. However, some of the sulfur-bearing species remain difficult to remove. Attempts to remove the remaining sulfur-bearing species by adsorption onto silica have also proven successful. Using gas chromatography with a sulfur detector and mass spectrometry we have successfully begun to characterize some of the sulfur-bearing species.
We have adapted the ERRC in situ transesterification method to successfully make biodiesel from sorghum bran and from sorghum distillers dried grains and solubles. The chemical composition of this new type of biodiesel was analyzed and the fatty acid methyl esters were found to be similar to those of biodiesels made from other feedstocks and processes. We have confirmed that the remaining coproduct meal contains little or no residual oil, fatty acid methyl esters or other lipids.
Objective 5: The economic impact of the new skeletal isomerization process for producing the isostearic acid was successfully evaluated using the SuperPro Designer computer software. The model predicted that the overall production cost of the isomerization process is competitive compared to the current technology. The process of our economic model was based on 10 million pounds of isostearic acid annually produced or 10% of the global market consumption. The results predicted that the unit production cost of the isostearic acid using our new process is competitive with the current technology.
We have successfully worked with engineers to construct a batch mode 1 Liter size reactor which can run reactions at high pressures and high temperatures. With this batch reactor, a tenfold increase in the production of isostearic acid was achieved with an environmentally friendly and economically feasible solid catalyst. The process with this reactor was found to be reproducible. Furthermore, the distribution of the products and conversion were found to be very similar to the numbers from the small scale production.
A significant amount of time was spent in the scale up of reaction conditions to make, purify and characterize the phenolic branched-chain lipids and their physical properties of the products are now being evaluated.
The phenolic branched-chain lipids were found to be potent antimicrobials against Gram-positive bacteria including Listeria innocua, Bacillus subtilis, and Enterococcus faecium. Compared with the minimum inhibitory concentrations in the literature, our phenolic lipid compounds are much stronger than the common additives used by the industry. Unfortunately, preliminary results show that the compounds are less effective against Gram-negative bacteria and they do not have good antioxidant properties.
Accomplishments
1. Using sorghum wax to produce Distillers Milo Oil. Ethanol plants occasionally use sorghum (milo) as a feedstock, and in the process produce Distillers Milo Oil. ARS researchers at Wyndmoor, Pennsylvania have evaluated the chemical composition of Distillers Milo Oil and have determined that these oils are like Distillers Corn Oil and that both could potentially be used for biodiesel and animal feed applications. Also, Distillers Milo Oil contains significantly higher levels of wax (1-2%), which can be recovered as wax. This sorghum wax has similar physical properties to commercial imported carnauba wax. Ethanol plants that are fermenting sorghum to produce Distillers Milo Oil can also produce sorghum wax as an additional new valuable coproduct.
Review Publications
Harron, A.F., Powell, M.J., Nunez, A., Moreau, R.A. 2017. Analysis of sorghum wax and carnauba wax by reversed phase liquid chromatography mass spectrometry. Industrial Crops and Products. 98:116-129.
Qiu, S., Yadav, M.P., Yin, L. 2017. Characterization and functionalities study of hemicellulose and cellulose components isolated from sorghum bran, bagasse and biomass. Food Chemistry. 230:225-233.
Jin, Q., Li, X., Cai, Z., Yadav, M.P., Zhang, H., Zhang, F. 2017. A comparison of corn fiber gum, hydrophobically modified starch, gum arabic and soybean soluble polysaccharide: interfacial dynamics, viscoelastic response at oil/water interfaces and emulsion stabilization mechanisms. Food Hydrocolloids. 70:329-344.
Jin, Q., Cai, Z., Li, X., Yadav, M.P., Zhang, H. 2017. Comparative viscoelasticity studies: Corn fiber gum versus commercial polysaccharide emulsifiers in bulk and at air/liquid interfaces. Food Hydrocolloids. 64:85-98.
Lew, H.N., Latona, R.J., Wagner, K., Nunez, A., Ashby, R.D., Dunn, R.O. 2016. Synthesis and low temperature characterization of iso-oleic ester derivatives. European Journal of Lipid Science and Technology. 118:1915-1925.
Yadav, M.P., Kale, M., Hicks, K.B., Hanah, K. 2017. Isolation, characterization and the functional properties of cellulosic arabinoxylan fiber isolated from agricultural processing by-products, agricultural residues and energy crops. Food Hydrocolloids. 63:545-551.
Kale, M., Yadav, M.P., Hanah, K. 2016. Suppression of psyllium husk suspension viscosity by addition of water soluble polysaccharides. Journal of Food Science. 81(10):E2476-E2483.
Liu, Y., Yadav, M.P., Chau, H.K., Yin, L. 2017. Peroxidase-mediated formation of corn fiber gum-bovine serum albumin conjugates: molecular and structural characterization. Carbohydrate Polymers. 166:114-122.
Gashua, I.B., Williams, P.A., Yadav, M.P., Baldwin, T.C. 2016. Characterisation and molecular association of Nigerian and Sudanese Acacia gum exudates. Food Hydrocolloids. 51:405-413.
Nwokocha, L.M., Senan, C., Williams, P.A., Yadav, M.P. 2017. Characterisation and solution properties of a galactomannan from bauhinia monandra seeds. International Journal of Biological Macromolecules. 101:904-909.
Labourel, A., Crouch, L.I., Brásb, J.L., Jackson, A., Rogowski, A., Grav, J., Yadav, M.P., Henrissat, B., Fontes, C.M., Gilbert, H.J., Najmudin, S., Basle, A., Cuskin, F. 2016. The mechanism by which arabinoxylanases can recognize highly decorated xylans. Journal of Biological Chemistry. 291(42):22149-22159.
Johnston, D., Moreau, R.A. 2017. A comparison between corn and grain sorghum fermentation rates, distillers dried grains with solubles composition, and lipid profiles. Bioresource Technology. 226:118-124.
Singh, A., Geveke, D.J., Yadav, M.P. 2016. Improvement of rheological, thermal and functional properties of tapioca starch using gum arabic. LWT - Food Science and Technology. 80:155-162.
Mendez-Encinas, M.A., Carvajal-Millan, E., Yadav, M.P., Valenzuela-Soto, E.M., Figueroa-Soto, C.G., Tortoledo-Ortiz, O., Garcia-Sanchez, G. 2016. Gels of ferulated arabinoxylans extracted from distillers dried grains with solubles: rheology, structural parameters and microstructure. In: Masuelli, M., and Renard, D. editors. Advances in Physicochemical Properties of Biopolymers. Part 1. Bentham Science, Emirate of Sharjah, United Arab Emirates. p. 202-214.
Malhotra, B., Kharkwal, H., Yadav, M.P. 2017. Polymers targeting habitual diseases. In: Kharkwal, H., Srinivas J., editors. Natural Polymers for Drug Delivery. Oxfordshire, UK: CABI. p. 171-182.
Malhotra, B., Kharkwal, H., Yadav, M.P. 2017. Cellulose based polymeric systems in drug delivery. In: Kharkwal, H., Srinvas, J., editors, Natural Polymers for Drug Delivery. Oxfordshire, UK: CABI. p. 10-21.
