Technological watch

Researchers at the University of Louisville Conn Center for Renewable Energy Research and Department of Mechanical Engineering are working to transform soy hulls left over from soybean processing into valuable food and industrial products. The United Soybean Board has awarded $350,000 to UofL to further develop methods for using soy hulls in modified fiber composites for 3D printing applications and produce the sugar substitute xylose as a value-added product.
Extracting Fibers for Lightweight Composites
This project will pilot a commercially viable process to convert soybean hull biomass into a low-calorie, diabetic-friendly sugar substitute while simultaneously extracting micro and nanoscale fibers to be used for lightweight fiber composites and thermoplastic packaging products via 3D printing.
“Agriculture and agricultural processing are keys to economic development and employment in the U.S. Xylose separation and use of soy hull fibers for natural fiber composites are potent opportunities for addressing worldwide farming economics, nutrition issues and material needs from a renewable source,” said Mahendra Sunkara, director of the Conn Center. “In conjunction with BioProducts LLC, the Conn Center expects the development of a pilot-scale operation in the next two years.”

The UofL project will utilize the soy hulls to produce xylose, a natural and low-calorie sugar, using a patented process developed by UofL and licensed by BioProducts, LLC, based in Louisville. After xylose extraction, the residual fiber, which is about 80% of the starting biomass, has a modified fiber structure that can be used as a natural fiber in composites for 3D printing applications.
Several Possible Applications for Natural Fiber Composites
These natural fiber composites also have potential uses in the automotive, civil engineering, military and aerospace industries, which rely on petroleum-based fiberglass and expensive carbon fiber composites to reduce weight and maintain assembly strength over all-metal constructions. The Conn Center project pursues the development of a stable and efficient method to process the hemicellulose-removed biomass from soybeans into lightweight natural fiber composites.
The food-grade sugar xylose from soy hulls also has high value industrial applications. This sugar can be used to produce cyclopentadiene, a key ingredient in cyclic olefin copolymer (COC), an amorphous thermoplastic used in polyolefin “shrink films” for medical, food safe and industrial packaging.
The new USB grant will fund pilot phase development of innovations resulting from previous research at UofL, including 3D printing using soy hull-polymer composite filaments, xylose separation, and additive manufacturing prospects, as well as a patent application on polymer composite feedstock production.
Major Challenges in Production
The major challenge of utilizing soy hulls to produce sugars and fibers is to create efficient, economical and achievable technology at a commercial scale. Meeting these three criteria elevates the value of this biomass. Currently, one limited outlet for soy hulls is as animal feed. Processing the hulls for a high value product such as xylose could make growing soy more profitable for farmers.
In the pilot phase, the team will pursue process optimization and design to meet the demands of a commercially viable process. This includes large volume production of xylose and composite filament samples for evaluation by commercial partners in the food and 3D printing industries.