Project : USDA ARS

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Research Project: Bioproducts and Biopolymers from Agricultural Feedstocks

Location: Bioproducts Research

2024 Annual Report

Objectives
Objective 1 encompasses processing technologies primarily for cellulosic feedstocks including hemp, a potential new specialty crop in the U.S. Research on objective 1 will focus on fiber-based packaging, particularly insulative and/or cushioning foam packaging and nanofiber films and composites. Objective 2 encompasses a broader range of feedstocks and includes starches and other carbohydrates beyond starch and cellulose as well as polyhydroxyalkanoates that are produced by bacteria. The primary objective is to utilize renewable polymers that are degradable in both garden compost and marine environments to make bioproducts designed for single-use food and packaging items. Objective 3 focuses on sustainable solutions for chemical products, particularly antibiotics, that are a growing health or environmental concern. The focus will be to use small molecules that bind or associate at critical concentrations to form active complexes with specific functions. Below the critical concentrations, the active complexes dissociate into benign molecules. Objective 1: Enable new technologies to manufacture fiber/nanofiber-based bioproducts. • Sub-objective 1A: Enable new technologies for making fiber-based foam products with moisture and grease/oil resistance. • Sub-objective 1B: Create consumer products utilizing hemp fiber. Objective 2: Enable new technologies for biopolymers and their blends. • Sub-objective 2A: Develop plastics and composites for consumer products that are readily degraded in marine and soil environments. • Sub-objective 2B: Develop microorganisms for novel biopolymer production. • Sub-objective 2C: Develop new technologies to process biopolymers into industrially-relevant products. Objective 3: Develop bioactive materials that are designed to minimize ecotoxicity and biocide resistance.

Approach
Hypothesis 1A: Fiber-based materials can be made into rigid, insulative foam products or non-foam composites with moisture and grease/oil resistance. Rigid foam samples will be made with agricultural fibers, foaming agent, and sizing agents. The rigid foam will be characterized by testing the mechanical and thermal properties of the foam. If the use of agricultural fibers is unsuccessful or too expensive, kraft fiber from wood pulp will be used in the study. Hypothesis 1B: The hypothesis statement will be provided by the scientist who fills the vacant position in the CRIS. Biomass left over from CBD extraction from various industrial hemp cultivars will be pulped and used as a source of nanofibers. Water soluble film formulations will be provided by our CRADA partner and treated with nanofibers to evaluate their effect on mechanical properties. If nanofibers from hemp do not desired properties, biomass resources provided by our cooperators from Brazil. Hypothesis 2A: Marine degradable polymers and composites can be processed into bioproducts including films, foams, and molded articles. We intend to promote crystallization of thermoplastic starch (TPS) during and after extrusion and molding as a means of enhancing moisture resistance and improving strength without reverting to chemical modification or blending. Commercial starches from various agricultural sources and with varying amylose:amylopectin ratios will be evaluated and formed into TPS using twin-screw extrusion. Blends of TPS and wood fiber, cellulose nanocrystals/nanofibrillar cellulose from hemp or corn stover will be prepared, processed by extrusion and/or film blowing, and characterized. Other biopolymers or mineral additives will be used in formulations if the properties of TSP are not acceptable. Hypothesis 2B: Microorganisms that use methane (methanotrophs) or other carbon sources (Bacillus subtilis) can be engineered to improve production processes and generate valuable biopolymer additives. We will use overexpression of targeted proteins to increase cell hydrophobicity in methanotrophs. If this approach is unsuccessful, the membrane proteins that target proteins regulate will also be singled out to change their expression. Hypothesis 2C: Active nutritional supplement can be produced at large scale by Bacillus megaterium.: B. megaterium strains within our own inventory will be used to produce poly-3-hydroxybutyrate (P(3HB)) trimers as active nutritional supplements. If insufficient quantities of 3HB trimer are produced, another strategy would be to isolate fungal or bacterial depolymerases for their ability to release trimers from P(3HB). Hypothesis 3: Judicious use of reversible actives (e.g. antimicrobials) will minimize negative human health effects, ecotoxicity and biocide resistance. We will incorporate reversible bonds in traditionally persistent chemicals such as cationic guanylhydrazones to minimize environmental toxicity and biocide resistance. If activity is affected by anionic additives, we will utilize hydroxamic acids.

Progress Report
This report documents fiscal year (FY24) progress for project 2030-41000-067-000D, titled, “Bioproducts and Biopolymers from Agricultural Feedstocks”. In support of Objective 1, ARS researchers in Albany, California, developed a foam technology for making molded plant-fiber foam panels as a potential replacement for plastic foam used in billions of packages shipped in the United States each year. Foam panels were used in making a thermal box replacement for polystyrene foam shippers. Fiber foam panels two inches in thickness gave identical thermal properties as polystyrene foam with walls that were one and a half inches in thickness. The results were encouraging but one of the limitations of the fiber foam was its moisture sensitivity. Research was performed to address this problem as part of Sub-objective 1A. The use of biodegradable waxes was investigated as a means of improving moisture resistance. The results show that paraffin and carnauba waxes provide the best moisture resistance while having minimal effect on foaming properties. These waxes do not hinder the biodegradability and compostability of the fiber foam products. One of the barriers to commercialization of the fiber foam process is the amount of time and energy required to oven dry the samples during the final step of fabrication. This issue is currently being addressed by exploring the use of alternative foaming methods that don’t require water in the fabrication process. This research is being supported through a two-year Trust agreement with an industrial partner. The industrial partner has a team of process engineers and is helping to scale-up the process for pilot-scale production with the intent of commercializing the fiber foam technology. In support of Objective 3, ARS researchers in Albany, California, developed novel compositions and active ingredients for food safety. Traditional food processing aids, such as hypochlorite and peracetic acid, reduce bacterial pathogens, such as Salmonella, Listeria, E. coli, and Campylobacter on foods, such as fish, poultry, and eggs. While these substances are effective at eliminating pathogens in a short period of time, they introduce workplace hazards and food quality and flavor issues due to their high inherent reactivity as acids and oxidants. ARS researchers partnered with a CRADA partner to develop processing aids that perform as well as traditional chemistries, but without the hazards. One composition matches the performance of gold-standard peracetic acid in total plate count bactericidal testing in as little as 15 second contact times. This composition can be safely transported at 84% solids, compared to 15-23% solids of peracetic acid, reducing transportation and material costs. Novel actives ingredients are being developed that are non-hazardous to skin, non-volatile and thus safer for workers, and specifically designed to eliminate Salmonella biofilms in food processing applications. Funding for this work exceeds $461,000.00 over three years.

Accomplishments
1. Thermal shippers made of plant fiber foam. Thermal shippers that are commonly used to ship chemicals, medical supplies and other thermally sensitive items are typically made of polystyrene foam; a material that is harmful to the environment. ARS scientists in Albany, California, have made a thermal box made of plant fiber that insulates as well as commercial thermal shippers. The fiber foam is lightweight and can be recycled in well-established paper recycling streams. In addition, the materials in the foam are renewable, compostable and biodegradable. The results of this research could help in efforts to replace polystyrene foam containers with environmentally friendly alternatives.

U.S. DEPARTMENT OF AGRICULTURE

Bioproducts Research: Albany, CA