Tennessee is home to more than 60,000 farms and millions of acres of forest. Agriculture and forestry contribute more than $100 billion to the state’s economy while fueling rural communities. But local droughts, rising production costs and volatile global markets are putting the economic vitality of these key Tennessee sectors at risk.
Meanwhile, around the globe, only about 6% of all extracted petroleum, metals and other resources are reused or recycled. Products made with metal, minerals, petroleum and other materials are discarded every day — and the value of those resources is lost from the economy. Raw resources are extracted and transformed into new materials to replace what was lost.
At first glance, local agriculture and global resource efficiency may appear unconnected. But researchers at the University of Tennessee, Knoxville, have a unique perspective built on interdisciplinary collaboration and a deep understanding of industry needs: They see how developing a different economic model — the circular bioeconomy — will address both challenges at once.
“Our big-picture vision is to responsibly grow and manufacture resources here in Tennessee, then prevent waste by reintroducing used resources into our farms, forests and factories,” said Nicole Labbé, a professor in the UT Institute of Agriculture and director of the university’s Center for Renewable Carbon. “This is about helping society thrive by starting locally — with all eyes on Tennessee as a model to follow.”
Understanding the model
The circular bioeconomy concentrates on using
renewable biological resources like plants rather than petroleum-based resources to manufacture high-quality materials, fuels, chemicals and other products. These bioderived products are designed to keep valuable resources in the cycle of production and use for as long as possible with as little waste as possible.
UT faculty work across all three major phases of the circular bioeconomy: growing, harvesting and processing the natural resources; designing and manufacturing bioderived products to meet industry performance goals; and engineering product end-of-life solutions.
Across those phases, researchers focus on a wide variety of interconnected topics. Some work from the ground up — helping farmers and foresters achieve greater crop yields using less water, fertilizer and other inputs. Faculty employ genetics and genomics to develop fast-growing tree species or perennial grasses that possess targeted chemical and anatomical traits or structural components suited for making different types of materials.
Other researchers are creating better ways to isolate and transform those plant components — particularly cellulose, lignin and hemicellulose, three highly abundant natural polymers found in plant cell walls — into materials and products that meet criteria for various industry applications. They design the products, study consumers’ willingness to use them, and plan pathways for industry or consumers to reuse, recycle or compost products at the end of their useful life.
Investing in the entire circle
UT’s history with plant-derived product research spans nearly three decades. Originally, researchers sought to expand applications for Tennessee’s forestry industry. They primarily concentrated on converting biomass — in this case, tree trunks, branches, leaves and residues like sawdust — into specific chemical and structural components that could be used to manufacture new materials.
In the late 2010s, Labbé and other professors expanded their approach. They started thinking in terms of circular bioeconomy systems — the sum of interconnected steps from plant to product and back again. Such systems are complex to design and implement because they bridge research disciplines, industries and supply chains.
UT faculty rose to the challenge, cultivating expertise and leadership at every level of the circular supply chain.
In 2024, the university and Oak Ridge National Laboratory made a joint commitment to invest $20 million over five years to accelerate world-leading circular bioeconomy innovation in Tennessee. As part of that initiative, UT continues to build capacity to engage a wide range of industries in research and implementation.
“I hope the new generation of scientists sees the vital support we receive from the UT and UTIA administrations, the investment in meaningful innovation, and they want to be part of this,” Labbé said.
Labbé leads what she calls UT’s circular bioeconomy systems alliance, a suite of distinct initiatives that advance relevant scientific discoveries, industry partnerships and real-world applications. Specific projects within those initiatives focus on different plant species, industries and phases of the circular supply chain.
Collectively, the initiatives build toward four shared objectives: improving resource efficiency and cost-effectiveness in the system; quantifying social, environmental and economic value to inform system improvements; empowering intelligent industry decisions that will benefit communities; and engaging the next generation of Tennessee’s workforce in circularity.
“UT research is focused on making life and lives better,” said Deb Crawford, UT’s vice chancellor for research, innovation, and economic development. “Our long-term commitment to the circular bioeconomy aligns closely with our research priorities and mission as a modern land-grant university. Our highly collaborative transdisciplinary approach is a differentiator that continues to expand our impact in bold new ways.”
Improving efficiency from farm to fuel
Abdoulmoumine and a team of plant scientists, agronomists, biosystems engineers, chemists, AI modelers and industry professionals seek to make plant-based aviation fuel more cost-competitive compared to conventional petroleum-based fuel.
“UT and UTIA excel in this space because we have an integrated perspective that covers feedstock production and natural systems stewardship, transportation, product manufacturing, community impacts, economics and industry needs,” Abdoulmoumine said.
Nourredine Abdoulmoumine, associate professor in UT’s Department of Biosystems Engineering and Soil Science, leads a project funded by the U.S. Department of Energy that contributes to a nationwide goal to scale up domestic production of sustainable aviation fuel.
The team has established demonstration and research plots on farms that supply Genera, a local industry partner that manufactures molded fiber packaging. There they study how Tennessee farmers can more efficiently and economically grow miscanthus and biomass sorghum to produce sustainable aviation fuel. These grasses can be grown on less productive farmland, where they don’t compete with food crops.
One key to greater efficiency is to increase soil health without using synthetic fertilizers. The team is investigating the results of substituting biochar and poultry litter for synthetic fertilizer, which is typically a large expense for farmers. Biochar is made from grass and tree components that do not go into the fuel. When returned to the soil, it provides value to farmers by enhancing soil health and crop production.
The team is mapping where in Tennessee to grow these grasses to maximize production and transportation efficiency and to create the biggest return on investment for local communities. Finally, they’re exploring how to increase cost effectiveness by developing additional products that can be manufactured from the same grasses at the same time.
“Let’s say we start with one ton of perennial grass. We break down the biomass into its structural and chemical components, but only 80% of that has the right properties to be made into sustainable aviation fuel,” Abdoulmoumine explained. “We’re figuring out how to use the other 20%. That portion might make more sense for molded fiber automotive parts or specialty packaging. Those things would become coproducts.”
Income from high-value, lower-volume coproducts would allow the price of the fuel to be reduced without compromising overall profitability. The strategy would make sustainable aviation fuel more attractive to produce and to purchase, helping the U.S. achieve its goal while creating a new source of income for Tennessee’s farmers.
Developing automotive end-of-life solutions
With more than 900 companies operating across the state, the automotive sector is Tennessee’s largest manufacturing sector and a key player in growing the market for plant-derived circular products.
UT researchers including David Harper, a professor in the Center for Renewable Carbon with a joint appointment in the Tickle College of Engineering, have collaborated with Volkswagen Group of America over the past six years to produce composite materials in which plastics are combined with up to 60% natural fibers. The work has resulted in multiple publications and a patent with legal protection in more than 150 countries.
The biobased composite reduces plastic use in interior vehicle components, decreases part weight and improves part performance. Engineering end-of-life solutions, however, has posed a challenge: traditionally, the base materials must be separated before recycling, and common recycling methods were thought to degrade the materials’ values.
To test the validity of those precepts in real-life scenarios, Harper and colleagues have been studying the performance of paper fiber–reinforced polypropylene composites after they have been recycled multiple times using mechanical processes, which are widely available in many communities.
Together with Labbé, Harper has developed a different type of recycling process that breaks down composites into their petroleum-based and plant-derived components — in this case, polypropylene and glucose — without degrading either component’s properties.
The process uses a mechanical method to expose the cellulose fibers to water and biological enzymes. That mixture prepares the cellulose to be converted into new plant-based polymers, chemicals or fuel. The polypropylene is recovered and reused with virtually no degradation, allowing it to stay in use longer.
Scaling implementation across the Southeast
In July, UT’s circular bioeconomy researchers celebrated a milestone achievement: an award of up to $160 million from the National Science Foundation over the next 10 years to support the BRIDGES Engine.
A collaboration involving UT, the HudsonAlpha Institute for Biotechnology, Auburn University, AGgrow Tech LLC and long-time UT partner Volkswagen Group of America, the initiative will tackle critical needs facing rural America such as more robust agricultural markets, greater economic diversification and better job opportunities.
BRIDGES will engage farmers in growing specially developed perennial grasses on underused and low-productivity land in rural areas of Tennessee and Alabama. Those grasses will be turned into high-demand automotive, construction and packaging products used commercially by industry partners.
UT brought its active long-term relationships with packaging, automotive and chemical partners to the BRIDGES Engine, which has built a collaborative ecosystem of 85 members including 52 industrial partners. Together they will ensure that research-based solutions are pertinent to multiple supply chains.
The project team estimates that BRIDGES will generate tens of millions of dollars in additional annual income for Tennessee farmers and create thousands of jobs across the state. Bioproducts manufacturing is expected to attract more than $2 billion in private capital investment and create thousands of better and higher-paying manufacturing and supply chain jobs.
Mapping efficiency and accelerating development
Abdoulmoumine is applying artificial intelligence to help the BRIDGES team start turning those estimates into reality.
He’s currently developing a decision support tool that will integrate AI to provide a clearer picture of complex supply chain logistics. The BRIDGES team and industry partners will use the tool to decide how to most efficiently plug local biobased materials and components into existing industry supply chains.
The tool will also help determine prime opportunity zones for developing future biobased industries. For example, it may identify a priority supplier — a single company whose relationships with multiple consumer brands would make a big difference in biobased materials adoption. Or it may identify a priority geographic area with multiple relevant suppliers, which could greatly increase transportation efficiency and lower costs.
Abdoulmoumine is establishing AI-enabled workflows that will speed up engineering design of new technologies, processes and even entirely new production facilities. These workflows will streamline the costly multiyear engineering processes required before a new facility can be built.
Abdoulmoumine pointed out, “It’s not enough to develop biobased alternatives to products that already exist. To drive more widespread adoption, our value proposition to industry must be that this biobased alternative provides better performance than what you already use.”
Developing high-performance materials and products is traditionally a lengthy, intensive process. Researchers for BRIDGES and other circular bioeconomy projects are actively developing AI-powered models that will accelerate the pace.
Specifically, these models will integrate the laws of physics and chemistry with rapid processing and real-time data analysis to help researchers strategically predict and screen more possibilities for suitable materials or product designs.
“The models will help us better understand the physics or chemistry behind certain performance drivers,” Abdoulmoumine said. Such insights will guide researchers in making specific changes — whether to processing conditions like temperature and moisture or to the fundamental properties of a particular plant variety — to maximize the strength, compostability and other beneficial characteristics of end products.
Seeing circles, not lines
“Our successes this year, particularly BRIDGES, are the result of 20-plus years of our research being moved from lab to implementation,” Labbé said. “We hope the model we develop will become a roadmap for other regions using their respective local resources, and we hope to help people think about what comes after the first use of a resource. I’m grateful UT understands the importance of our work to implement an innovation that will change everyday life for the better, starting here in Tennessee.”
Beyond Traditional Agriculture
As the circular bioeconomy grows, so too does the understanding of biological resources beyond perennial grasses and fast-growing tree species.
Orlando Rojas, the recently appointed UT-Oak Ridge National Laboratory Governor’s Chair for Circular Biomaterials, brings experience working with ocean-sourced biomass as well as residues from the production of forestry products. His research experience is relevant for sustainable manufacturing, biomedical systems and energy storage, among other industries.
Toni Wang, the Charles E. Wharton Institute Professor in UT’s Department of Food Science, and Jeffery Tomberlin, who will join the UT Institute of Agriculture in early 2027 as a Chancellor’s Excellence Professor, are investigating one of nature’s most efficient recyclers: black soldier fly larvae. The larvae can convert food waste, agricultural residues and even certain contaminated materials into protein- and lipid-rich biomass, which may one day be used to produce aviation fuel and biobased fertilizer.
Cong Trinh, Ferguson Faculty Fellow and chemical engineering professor in the Tickle College of Engineering, continues to develop his patented biomanufacturing technology. It uses renewable resources as the feedstock and employs fermentation to convert them into high-value molecules. Molecules like butyl acetate, which have long been produced through chemical synthesis using petroleum-based feedstocks, are used by industry for a host of applications including aviation fuel, pharmaceuticals and microchip production.
Up-and-Coming Replacements for Forever Chemicals
The chemicals known as PFAS — per- and polyfluoroalkyl substances, often called forever chemicals because of the way they build up in the environment and in the body — have been used for numerous household products. PFAS coatings, for example, make paper-based food packaging resistant to oil and water.
UT researchers are creating alternative plant-based coatings and additives for use in packaging and other products.
David Harper’s group is developing biobased films to line rigid natural fiber packaging, with the aim of replacing common plastic food containers with compostable alternatives that perform equally well. Nicole Labbé’s research group, along with that of Professor Siqun Wang, a fellow researcher in the Center for Renewable Carbon, has recently demonstrated that a lignin-based coating on paper can successfully resist oil and can be composted.
So far the latter project has led to three invention disclosures, a U.S. provisional patent application, multiple journal publications and educational workshops — and a new way to create plant-based value that will benefit industry, individuals and the environment.