Project : USDA ARS

ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Sustainable Biofuels and Co-products Research » Research » Research Project #439256

Research Project: Chemical Conversion of Biomass into High Value Products

Location: Sustainable Biofuels and Co-products Research

2024 Annual Report

Objectives
1. Develop new functional (phenolics derived from fractionated bio-oils, monomeric sugars from carbohydrate, and amino acids) biobased fatty acid products from chemical technologies. Subobjective 1a: Development of monomeric fatty acid-based products with antimicrobial properties. Subobjective 1b: Development of polymeric fatty acid products from the monomeric sugar based-fatty acid products. 2. Develop chemical and enzymatic approaches to convert triglycerides derived from low (or no) value waste or bio-residue into valuable commercial products. 3. Develop innovative technologies to modify nonfermentable hemicellulosic and cellulosic carbohydrate polymers isolated from lignocellulosic biomass including agricultural residues, agricultural processing by-products and energy crops into commercially viable novel co-products.

Approach
To address these objectives, research tasks will be performed with industrial partners and other collaborators. The approach will involve catalyst selection, process design, product isolation, purification and characterization methodologies to develop new functional biobased products. First, recyclable solid catalysts will be explored to introduce branching between the functional hydroxyl group and unsaturation on the fatty acid alkyl chain to generate functional fatty acid monomers with improved antimicrobial properties. Second, the functional monomers will be engineered into hydroxylic-oil based polyurethane biopolymers with active hydroxy sites on the surfaces to prevent buildup of bacteria colonies. Third, functional groups will be introduced on unsaturated carbons of the fatty acid chain of triglycerides through chemical and enzymatical methods. The resulting triglyceride-based products will have improved lubricant solubility and low temperature properties. Finally, chemical modification will be developed to utilize the isolated carbohydrate polymer fractions and generate new carbohydrate products. Isolation of carbohydrate polymers will be performed on agriculture processing byproducts and agricultural residues using an improved isolation method. All functional products will be subjected to analytical characterizations for structural identification and will be evaluated for their applications and commercial uses. Attaining these objectives will create superior new antimicrobial, antioxidant, emulsifier, biolubricant, and biopolymer functional materials.

Progress Report
Significant progress was made on all three Objectives and their Sub-objectives. Under Sub-objective 1a, SuperPro Designer software was used to estimate the capital and operating costs of the patented arylation zeolite process, which involved the introduction of a phenolic functional group to the fatty acid to produce the phenolic-branched chain fatty acid monomeric products. These lipid-based monomers are odorless, viscous liquids at room temperature and can be functionalized into polymerized products that exhibit strong antimicrobial activities against bacteria. Two different techno-economic models were built using soybean fatty acid and brown grease fatty acid as starting feedstocks. Brown grease is a waste oil recovered from food processing and wastewater treatment and is found to be 60% cheaper than soybean oil from the models. This result validates our efforts in utilizing waste materials to make the process more economical. The biodegradability and toxicity of these lipid-based products were determined by collaborating with the University of Delaware on a project funded by the National Institute of Food and Agriculture (NIFA). The biodegradability test was performed by placing the products in soil to determine the degradation by measuring the carbon dioxide produced over time. The preliminary results showed that the products have not exceeded the degradation of cellulose. This work is ongoing to further modify the products to increase their biodegradability. The developmental toxicity of these lipid-based monomers was also investigated using a chicken embryonic assay. The products were injected into the fertilized leghorn eggs at various concentrations and examined for a period of twelve days. The eggs were then dissected and assessed for abnormalities. The results showed the products varied in their toxicities. Among the test dosages at these concentrations (33-1333 ug/kg), some derivatives of these lipid-based products are found to be nontoxic, and these will be the ones that will be selected for further development. In Sub-objective 1b, arabinoxylans isolated from corn bran were dissolved in dimethyl sulfoxide at a much higher concentration than in water and then modified with octyl succinic anhydride using a thermal method to impart hydrophobicity to their structures. This method has the advantage of preparing larger quantities of modified biopolymers for further evaluation. The reaction products were studied as a function of the concentration of octyl succinic anhydride from 2-40% with yields >90%. The reaction products were purified to remove unreacted reactants and solvents. The purified products were characterized using fourier-transform infrared (FTIR), nuclear magnetic resonance (NMR), and thermogravimetric analyzer, which confirmed the formation of modified biopolymers. These products with varying degrees of substitution (0.04-0.12) were also evaluated for their emulsification properties and demonstrated superior emulsifying abilities, that can have potential in food and non-food applications. These biopolymers were also used to make biodegradable films. Work on these films is ongoing to study the mechanical, oxygen-barrier, antimicrobial, and biodegradability properties for potential application as biobased food packaging film and coating. A reaction to synthesize polyol through epoxidation of fatty acid esters followed by ring-opening using sugar molecules was also attempted using three different catalysts. The products were characterized using high performance liquid chromatography, FTIR, and NMR, which showed some degree of conversion to polyols. These polyols have the potential to be converted into rigid polyurethanes. All these value-added biobased products will help increase the utilization of agricultural processing byproducts. In Objective 2, in collaboration with Iowa State University, high oleic soybean oil (HOSOY) and regular soybean oil (RSOY) were subjected to isopropylation reaction using the previously ARS-developed procedure to produce isopropyl (i-Pr)-branched HOSOY (b-HOSOY) and RSOY (b-RSOY), respectively. Both products, i.e., b-HOSOY and b-RSOY were characterized with NMR, gas chromatography mass spectrometry (GC-MS), and compact MS to determine their chemical structures. NMR analysis revealed that b-HOSOY and b-RSOY incorporated 2.3 and 1.7 i-Pr groups per triglyceride molecule, respectively. Physicochemical and tribological properties, such as density, viscosity, oxidative stability, and low temperature properties of b-HOSOY and b-RSOY were determined. Both i-Pr-branched products showed higher viscosity, better stability, and improved cold flow properties in general, compared to their corresponding unbranched feedstocks. Branched products also exhibit advanced tribological behavior, e.g., b-HOSOY shows higher wear resistance than HOSOY. A detailed tribological property analysis of b-HOSOY and b-RSOY is being carried out to determine their potential use as biolubricants. In Objective 3, in collaboration with South Dakota University on a NIFA-funded project, the cellulosic fraction from agricultural biomass was isolated and solubilized using zinc ions and then cross-linked with calcium ions of different concentrations. A biodegradable film using a solution of cellulosic fraction in different concentrations of calcium ions was prepared, and its mechanical properties were studied. The result revealed that the increase of calcium ions significantly improved the tensile strength of the film in comparison to commercial polyethylene products. The biodegradability study of the film in the soil was conducted, which showed that 92-94% of the film was disintegrated after its burial in soil for 28 days. It was far better than the commercial polybutylene succinate starch and polybutylene succinate plastics, which disintegrated at only 7.2% and 1.2%, respectively. The new biodegradable material has great potential for replacing non-biodegradable plastic as packaging material. An application of hemicellulose B, isolated from grain processing by-products, for preparing a biodegradable antibacterial film was explored. Several combinations of hemicellulose B with carboxymethyl cellulose or methyl cellulose in the presence of a glycerol plasticizer were tried to make a strong film. After trying several methods, a methodology was optimized for casting the biobased films with very good mechanical and gas barrier properties. The result revealed that a film made with 60:40 hemicellulose B and carboxymethyl cellulose and glycerol plasticizer was the best. Work is in progress to study its antimicrobial properties. The developed film has the potential to be used as a biobased food packaging material with antibacterial properties. The development of such a biobased film product will help increase the utilization of grain processing byproducts.

Accomplishments
1. Variation in molecular structure affects the properties of biolubricants used in machinery, for electrical vehicle fluid, metal working lubricant, gear oil, hydraulic oil, or other applications. The use of fossil-based products raises concerns due to their lack of biodegradability and potential toxicity, which can have detrimental effects on the ecosystem. ARS scientists in Wyndmoor, Pennsylvania, have established a correlation between the molecular structure of biolubricants and their physicochemical properties, such as density, viscosity, lubricity, cold flow parameters, and oxidative stability. A series of structurally distinct triesters have been synthesized from a renewable feedstock via a green approach. Variations in structure, such as cis versus trans, saturation versus unsaturation, branching versus linear, and glycerol versus polyol backbone of triesters, result in notable alterations in their physicochemical properties. The results reveal invaluable experimental data for the development of application-based biolubricants with improved properties that are equivalent to fossil-based products.

U.S. DEPARTMENT OF AGRICULTURE

Sustainable Biofuels and Co-products Research: Wyndmoor, PA