Location: Sustainable Biofuels and Co-products Research
2020 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
New NP306 OSQR approved project plan entitled "Chemical Conversion of Biomass into High Value Products" is currently being established.
Develop technologies that enhance biodiesel quality to enable greater market supply and demand for biodiesel fuels and >B5 blends in particular: In collaboration with a commercial partner, multi-step syntheses were employed to synthesize six target sulfur-bearing compounds believed to be present biodiesel produced from ‘brown’ grease lipids (BGL) such as ‘trap’ grease and float greases. Modified protocols were used to synthesize the molecules before they were fully characterized with state-of-the art analytical instrumentation (13C NMR, FT-IR-ATR, and GC-MS). The positive identification of these molecules will lead to the development of protocols to eliminate these hard-to-remove compounds from BGL- derived biodiesel. The BGL used in this study were collected from local municipal underground grease traps and waste-water treatment plants at various times of the year. Furthermore, it was reported previously that the conversion of post-fermentation sorghum stillage (distillers dried grains with solubles, DDGS) to biodiesel improved from 30% to 70%. We have continued to improve the i.s.t. of the stillage by increasing conversion of the lipids in stillage to biodiesel from approximately 70% to greater than 90% as a result of feedstock pretreatment and modified synthetic procedures. Co-product meals continue to be collected for evaluation.
Develop technologies that enable the commercial production of new products and coproducts at lipid-based biorefineries: A new class of antimicrobial surfactant agents named functional phenolic branched-chain fatty acid arginate products has been successfully developed. This method is general and suitable for using any types of fatty acids as feedstocks. The products have been tested and found to possess strong antimicrobial activity against Gram-positive bacteria but are not as effective towards Gram-negative bacteria. The surface tension of these products is relatively low, indicating them to be good surfactants, and thus can be potentially used as antimicrobial surfactant agents.
Fatty acids are naturally abundant molecules with diverse and potent biological activities. In an ongoing project for a new objective, ARS scientists at Wyndmoor, Pennsylvania, chemically modified the carboxylic acid functional group present in fatty acids to explore the biological activity of the newly developed products. The carboxylic acid functional group of lauric acid, myristic acid and palmitic acids was modified with heterocyclic amines to form fatty acid amide derivatives. The fatty acid amide derivatives were evaluated for their effectiveness against gram-positive and food-borne pathogen Listeria monocytogenes strains. Pyrrolidine amide derivative of lauric and myristic acids have excellent inhibitory activity against the listeria monocytogenes strains. Therefore, the amide derivatives of lauric acid and myristic acid could be considered as alternative antibacterial agents to control listeria growth in food products.
In an ongoing project for a new objective, ARS scientists at Wyndmoor, Pennsylvania, have made a significant advancement on using the biochemical stimulants to increase the production of valuable lipids and docosahexaenoic acid (DHA) through biosynthesis. Biosynthetic potential of Aurantiochytrium sp. ATCC PRA-276 to synthesize lipid and DHA under the influence of five different biochemical stimulants, such as 2-phenylacetic acid (PAA; 30 ppm), humic acid (HA; 20 ppm), spermidine (SPD; 1.5 ppm), 1-methylcyclopropene (1-MCP; 200 ppm), ferric chlorides (FC; 3.2 ppm) are estimated. At 120 h of cultivation, the supplementation with an individual stimulant considerably elevates the biomass growth, lipid and DHA production in comparison to the control. This study indicates the potentiality of the employment of the above-mentioned biochemical stimulants in biosynthesis for cost-effectiveness in industrial-scale production of biomass, lipid and DHA productivities.
Isolated arabinoxylans from cereal grains processing by-products characterized and studied their functionalities. In addition to carbohydrate components, arabinoxylans also contain other components such as lignin, phenolic acids, and proteins. Due to importance of phenolic groups in forming arabinoxylan gels, scientists at the USDA-ARS in Wyndmoor, Pennsylvania, developed conditions for making phenolics and protein rich arabinoxylans with highly branched structure from cereal grains. It was found that arabinoxylans isolated at a lower temperature had more phenolic compounds, protein, and branched structure than extracted at a higher temperature. These arabinoxylans have potential to be used in drug delivery matrices and encapsulation of active ingredient as they can form strong gels.
Hemicellulose B (arabinoxylans) recovered from sorghum bran and the lignocellulosic portion of sorghum biomass and bagasse possess phenolic acid side chain groups that impart antioxidant properties. Polysaccharides that act as an antioxidant have potential utilization in the functional food or nutraceutical market. Scientists at the USDA-ARS in Wyndmoor, Pennsylvania, determined that the quantity of bound phenolic acids on arabinoxylan fractions from sorghum bran, biomass, and bagasse influenced the overall antioxidant capability of the polysaccharide. Sorghum biomass and bagasse contained the largest amount of bound phenolic acid at 13.1mg and 6.3 mg phenolic acid per 100 g arabinoxylan, respectively, while sorghum bran contained the lowest quantity of phenolic acids with less than 2 mg phenolic acid per 100 g arabinoxylan. As for antioxidant performance, sorghum bagasse arabinoxylan provided the best reducing capability, but sorghum biomass and sorghum bran arabinoxylan performed better as a free radical scavenger. Lastly, it was also determined that higher concentrations of arabinoxylans in solution showed a reduction in overall antioxidant capability due to the behavior of arabinoxylans in solution forming aggregates thus reducing antioxidant effectiveness. These results expand the potential utilization of arabinoxylan as a value-added co-product from biorefinery processes for applications as an added component to food formulations where antioxidant properties could boost nutritional value.
Accomplishments
1. New biobased antimicrobial epoxy coatings. Human beings are affected by various plagues, epidemics, and other contagious diseases that spread effectively through touch. ARS scientists at Wyndmoor, Pennsylvania, have engineered a family of advanced antimicrobial materials from modified fats. They found that the new fats can be used as surface coatings that can kill all kinds of bacteria over and over. These bio-polymers could function as antimicrobial pathogen prevention coatings for commercial and domestic use.
Review Publications
Yan, J., Deng, C., Zhu, Q., Qiu, S., Yadav, M.P., Yin, L. 2019. Rheological and emulsifying properties of arabinoxylans from various cereal brans. Journal of Cereal Science. 90:1-10. https://doi.org/10.1016/j.jcs.2019.102844.
Huang, K., Ashby, R.D., Fan, X., Moreau, R.A., Lew, H.N., Strahan, G.D., Nunez, A. 2020. Phenolic fatty acid-based epoxy curing agent for antimicrobial epoxy polymers. Progress in Organic Coatings. 14:105536. https://doi.org/10.1016/j.porgcoat.2019.105536.
