UC Riverside chemical engineering researchers have constructed a new biomass processing facility capable of transforming forestry and agricultural waste into pulp for fiber and textile products. The two-story pilot system, located at UC Riverside’s Center for Environmental Research and Technology (CE-CERT), uses a patented method called CELF—co-solvent enhanced lignocellulosic fractionation—to process low-grade biomass more efficiently and with less environmental impact than traditional methods.
“It’s cleaner, milder, and uses less energy than traditional kraft pulping,” said Charles Cai, associate research professor who invented the process and led the build-out of the pilot system at UC Riverside. “It doesn’t compete with lumber because it can transform substandard wood waste into an on-spec high-value pulp product.”
The sustainable pulp produced by this system has been qualified as textile-grade dissolving pulp, which is used in making cellulose-based fabrics such as rayon and lyocell. These materials are utilized by brands like Patagonia and Lululemon for sportswear and undergarments.
The CELF method is designed to be both energy-efficient and non-polluting. “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 said.
Unlike conventional kraft mills—which require severe temperatures, pressures, and caustic chemicals—the CELF system operates using 50 percent less energy to process waste materials such as forest thinning debris, orchard trimmings, and corn stalks. These types of biomass are often burned or left to decay, contributing to air pollution.
The CELF technology also avoids producing “black liquor,” a toxic byproduct from kraft pulping that can harm air and aquatic ecosystems. Instead, it yields non-toxic dissolving pulp along with purified lignin, fermentable sugar syrups, and gypsum. Lignin extracted from this process can be used in bio-polyurethane foam panels for home insulation or other biopolymer products. The gypsum produced matches that used in drywall manufacturing.
The pilot facility began operations by processing shredded wood debris from California forest clearings managed to reduce wildfire risks. Its first client is The Hurd Co., based in Santa Monica; the company is working with UC Riverside to convert almond orchard waste into high-grade dissolving pulp for use in activewear production.
The Hurd Co.’s equipment donations enabled completion of the pilot system after federal grant funds were suspended during the Trump administration.
UC Riverside now seeks business agreements with additional companies interested in developing biomass-based fibers or licensing the CELF technology. Because CELF systems can operate on a smaller scale than conventional mills, they may allow distributed production directly at farms or forest management sites where waste is generated.
Cai explained: “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.” He added: “In most cases, we’re also solving a waste problem. 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.”
