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

2025 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
Under Sub-Objective 1A development of phenolic branched-chain fatty acid antimicrobial agents and surface coatings has been completed. These products were synthesized by bonding the phenolic compounds from essential oils with fatty acids from vegetable oil and waste trap grease via an arylation route. The resulting honey- like liquids are stable, odorless, and easy to handle. These products can reduce Listeria (L.) monocytogenes by 6 log CFU (a million bacteria) and perform well on apples, showing effectiveness comparable to chlorine-based sanitizers. Toxicity results using a chicken embryo model showed variable toxicity at low concentrations; however, some phenolic products were non-toxic and selected for further development with National Institute of Food and Agriculture support. These coatings are effective against both L. monocytogenes and E. coli even after ten consecutive exposures, reducing the need for frequent reapplication. This long-lasting property comes from chemically bonded phenolics that resist wash off. These coatings can be formulated to be either rigid or flexible, making them resistant to bending or breaking during use. They also adhere well to surfaces (e.g., glass, wood, plastic, fabric), have strong mechanical strength, and withstand temperatures up to 300°C. Water and oil resistance tests on cotton fabric showed untreated samples absorbed liquids, while coated fabrics absorbed significantly less. A coating concentration of just 5% by weight was enough to make the fabric waterproof. Production costs were estimated using SuperPro Designer software to model the energy use, equipment, and operational expenses. Inputs included fatty acid, catalyst, phenolic, and resin. Outputs were phenolic product and a byproduct (iso-fatty acid, discussed in Objective 2). Based on the two- liter reactor data, a full economic feasibility analysis was completed, and the production unit cost was estimated to support commercial viability for bio-based antimicrobial bio-based coatings. Discussions with an oil company are ongoing to explore commercialization. Next steps include further testing to confirm product effectiveness, safety, stability, and biodegradability will continue in the project titled “Sustainable Bioproducts from Agricultural and Food Processing Waste.” Work on Sub-Objective 1B achieved the development of new sugar-fatty acid polymers through various modification routes with potential applications as emulsifiers, antimicrobials, films, and hydrogels for drug delivery applications. These sugar-fatty acid biopolymers were synthesized by esterifying fatty acid derivatives with arabinoxylan or AX (also used in Objective 3) as a representative sugar, isolated from agricultural processing byproducts, agricultural residue, and food processing wastes. A faster microwave-assisted process was also successfully developed and resulted in high yields of sugar-fatty acid biopolymers (>90%) with degrees of substitution ranging from 0.04 to 0.12. The final products are water-soluble, fluffy, white in color, and well-characterized using various analytical techniques. Apart from the earlier demonstrated applications of these biopolymers as superior emulsifiers and strong biodegradable food packaging films (with improved oxygen and water-barrier properties), these were also evaluated for their antimicrobial properties. These are found to be effective against foodborne bacterial pathogens, such as L. monocytogenes and Salmonella Typhimurium, and showed efficacy against food spoilage fungi such as A. prasiticus, P. digitatum, M. mucedo, and R. stolonifer strains. Due to the ease of solubility in water, these could be utilized as a spray (topical application) for food safety (food contact surfaces or on produce). Some of these biopolymers were also shown to form a hydrogel, and our university collaborator is investigating their cytotoxicity and potential use in drug delivery applications. Polyols were synthesized through epoxidation of fatty acid esters followed by ring-opening using sugar molecules and characterized with the potential to be converted into rigid polyurethanes. A Cooperative Research and Development Agreement was established with an industrial partner to explore additional applications, such as in the formulation of adhesives and cleaning products. Reducing feedstock costs by using a waste food product directly decreases the cost of the final. This work results in value-added products from agricultural processing byproducts, thereby helping farmers. These modified biopolymers will be explored in applications like lubes, greases, and asphalt binders in the project titled “Sustainable Bioproducts from Agricultural and Food Processing Waste.” Under Objective 2, notable progress has been made in developing biobased products via chemical modification of oils and fats. Several new synthetic routes have been developed and optimized to alter both animal fats and vegetable oils, resulting in biobased lubricants and antimicrobials. Various animal fats, including chicken fat, beef tallow, and lard, underwent a chemical process called isopropylation. This method introduces isopropyl groups into the fat chains by forming new carbon-carbon bonds. This is the first reported instance of modifying animal fats via this transformation. The isopropyl branches change the physicochemical properties of triglyceride molecules, broadening their applications. Specifically, this branching saturates the unsaturated fatty acid chains, improving their thermo-oxidative stability, also prevents proper stacking of fatty acid chains at lower temperatures, enhancing the cold flow properties. These two features are vital for biobased lubricant performance. These altered animal fats exhibit superior oxidative stability and viscosity index than fossil-based lubricants like polyalphaolefin. In collaboration with a university and funding from the North Dakota Soybean Council and National Institute of Food and Agriculture, this ARS technology was used to modify high oleic soybean and regular soybean oils. The modified oily products exhibited enhanced stability, cold flow, viscosity index, and wear resistance. Additionally, a class of novel molecules called trimethylolpropane supported triesters was developed. Plant-based fatty acids undergo skeletal isomerization to yield iso-fatty acids (methyl-branched fatty acids). Then reacted with trimethylolpropane through esterification to form trimethylolpropane-triesters. This process is waste-free. Trimethylolpropane-triesters are more stable than natural triglycerides due to the replacement of the glycerol backbone with trimethylolpropane. It generally shows improved cold flow, viscosity index, and wear resistance compared to both polyalphaolefin and natural oils. The research findings have been shared with several lubricant manufacturers under a Cooperative Research and Development Agreement to develop commercially viable products. Further, a general guideline linking the molecular structure of biobased lubricants to their physicochemical properties has been established. This valuable experimental data has led to new concepts for the upcoming five-year project titled “Sustainable Bioproducts from Agricultural and Food Processing Waste” aimed at developing application-oriented biobased lubricants and antimicrobials with properties comparable to fossil-derived products. In Objective 3 biodegradable and antimicrobial food packaging films were developed using fiber fractions (hemicellulose-B and the cellulose-rich fraction), isolated from agricultural by-products. Hemicellulose-B was conjugated with whey protein isolate to make food packaging films and coating solutions. These films significantly reduced populations of E. coli, L. innocua, and native microorganisms on tomatoes and fresh-cut apples stored at 4°C for up to 21 days. They also significantly inhibited Salmonella and bread fungi growth in media. The films showed good mechanical strength and effective moisture and gas barrier properties. Further work involved combining hemicellulose-B with carboxymethyl cellulose or methyl cellulose using glycerol as a plasticizer. The film made with a 60:40 ratio of hemicellulose-B to carboxymethyl cellulose and glycerol showed the best performance. AX (hemicellulose-B) was also used to make matrices for encapsulating the active ingredients by crosslinking it with an enzyme called laccase. The matrices, composed of crosslinked AX, sodium alginate (SA), and their mixture, were used to investigate the viability of bacteria (Lactobacillus rhamnosus GG, Streptococcus thermophilus, and B. longum). The crosslinked AX and crosslinked AX/SA mixture showed the highest encapsulation efficiencies ranged from 55-77%. After 28 days at 4°C under aerobic conditions, 7 log CFU (10 million) of Lactobacillus rhamnosus GG recovered from the crosslinked AX/SA mixture, compared to only 4 log CFU from the SA-only matrix. Thus, the crosslinked AX can be used to construct matrices for encapsulating and protecting probiotic bacteria during delivery to the colon. Biodegradable films were also developed using the aqueous solution of cellulose rich fraction with zinc and calcium ions, and their mechanical properties were evaluated. The result revealed that the increase of calcium ions significantly improved the tensile strength of the films compared to commercial films. Biodegradability tests proved that 92-94% of the cellulose rich fraction-based films disintegrated after 28 days, in contrast to only 7.2% and 1.2% disintegration for two commercial plastics, showing the strong potential for cellulose rich fraction-based films as replacements for non-biodegradable plastics. These findings will benefit U.S. farmers to capitalize on their byproducts to increase the profitability of their operations. Derivatization of hemicellulose-B and cellulose rich fraction to develop high-value products will be explored in the new project plan.

Accomplishments
1. Bacteria killing plant-based coatings. Plastic coatings are widely used to protect items like food packages and industrial products, forming a large and rapidly growing industry. Instead of relying on these plastics, ARS researchers in Wyndmoor, Pennsylvania, are developing surface coatings from agricultural materials like vegetable oils. They found a way to turn vegetable oils, including waste trap grease, into antibacterial coatings. The materials can be applied to various substrates (e.g., glass, stainless steel, fabric, plastic, wood), creating a non-sticky, durable surface coating that resists water and oil and remains effective in killing bacteria even after repeated use. Since they are made from renewable materials, they offer biodegradability in surface coatings, and benefit industries such as food packaging and industrial manufacturing.

2. Antimicrobial biopolymers. Foodborne pathogens such as Listeria monocytogenes, Salmonella enterica, E. coli, and other pathogens pose food safety risks to consumers continuously despite food control measures in many countries. This not only results in significant economic losses but also serious health hazards worldwide. A high-value water-soluble sprayable antimicrobial has been successfully developed using arabinoxylan isolated from waste agricultural products by scientists in Wyndmoor, Pennsylvania. This modified arabinoxylan is found to be highly effective against Gram-positive and Gram-negative bacteria. The modified arabinoxylan may inhibit fungal growth by using topical application and would be helpful to mitigate the effects of food spoilage fungi. This technology will benefit U.S. farmers and food industries by extending the shelf life of vegetables and fruits, and by adding value to the agricultural products, byproducts, and residues.

3. A novel bio-based antimicrobial with broad-range efficacy. The demand for natural and bio-based antimicrobials is growing, and the emergence of antibiotic-resistant pathogens necessitates the development of novel antimicrobial solutions. Natural and bio-based antibacterial agents are being developed to combat multi-resistant bacteria. ARS researchers at Wyndmoor, Pennsylvania, have developed a process to conjugate bioactive agents with plant-based unsaturated lipids, to produce novel bio-based antimicrobials. The developed product, trihydroxy benzyl fatty acid, has been evaluated for its antibacterial efficacy against both Gram-positive and Gram-negative pathogenic bacteria, as well as for its antifungal properties. This synthesized compound with a broad-range antimicrobial efficacy offers a viable alternative of toxic biocides. Natural and bio-based antimicrobials hold immense promises for food safety, health, and environmental sustainability. The potential uses of such novel compounds in various industries remains a topic of great interest. This technology will benefit farmers and producers by adding value to their products, byproducts, and residues.

U.S. DEPARTMENT OF AGRICULTURE

Sustainable Biofuels and Co-products Research: Wyndmoor, PA