UC Riverside’s chemical engineering team has built a new biomass processing facility capable of converting forestry and agricultural waste into pulp for fiber and textile products. The two-story pilot system, located at the university’s Center for Environmental Research and Technology (CE-CERT), uses a patented method called co-solvent enhanced lignocellulosic fractionation (CELF).
“It’s cleaner, milder, and uses less energy than traditional kraft pulping,” said Charles Cai, associate research professor who led the project. “It doesn’t compete with lumber because it can transform substandard wood waste into an on-spec high-value pulp product.”
The sustainable pulp from this process meets the standards for textile-grade dissolving pulp, which is used in making cellulose-based fabrics such as rayon and lyocell. These materials are commonly found in products by brands like Patagonia and Lululemon.
CELF technology offers several advantages over conventional kraft pulping methods. It operates under milder conditions, avoiding the severe temperatures, pressures, and caustic chemicals typical of traditional mills. “With CELF, the process is so mild that it doesn’t break down the material in a destructive way, so harsh conditions are avoided, and the byproducts are usable, not hazardous,” Cai explained.
Unlike standard mills that use whole logs from clear-cut forests, CELF can process low-grade biomass including forest thinning debris and orchard trimmings while using 50 percent less energy. These materials are often burned or left to decay—practices that contribute to air pollution.
Another key difference is that CELF does not produce “black liquor,” a toxic byproduct of kraft pulping known to harm air and aquatic environments. Instead, it generates non-toxic dissolving pulp along with purified lignin—which can be used for bio-polyurethane foam panels—and gypsum for construction materials.
“Lignin is a natural polymer found in the cell walls of plants that is cleanly extracted by our pilot system to make bio-polyurethane foam panels for home insulation, among other biopolymer products,” Cai said.
The pilot facility began operations using shredded wood debris from California forest clearings intended to reduce wildfire risk. Its first client is The Hurd Co., based in Santa Monica, which aims to convert almond orchard waste into high-grade dissolving pulp suitable for activewear production.
The Hurd Co.’s equipment donations helped complete construction after federal grant funds were suspended during the Trump administration.
UC Riverside now seeks agreements with additional companies interested in developing biomass-based fibers or licensing CELF technology. Because CELF systems can operate on a smaller scale than traditional mills, growers or agencies could potentially install units onsite to process their own waste streams.
Cai clarified: “We’re not introducing a new textile fiber. We’re using a cleaner and cheaper process to make the same dissolving pulp—but from what used to be waste.”
“In most cases, we’re also solving a waste problem,” he added. “We’re turning what would be a landfill or burn pile liability into something valuable—and doing it in a way that avoids the environmental costs of black liquor processing or deforestation.”
