A Sweeter Way to Make Green Products: University of Delaware Researchers Invent Novel Process for Extracting Sugars from Wood
by Tracey Bryant (University of Delaware) … A UD research team has invented a more efficient process for extracting the sugars from wood chips, corn cobs and other organic waste from forests and farms.
Basudeb Saha, associate director for research at UD’s Catalysis Center for Energy Innovation — a U.S. Energy Department-designated Energy Frontier Research Center — led the effort, which involved scientists from UD and from Rutgers University. The results are published in ChemSusChem, a top interdisciplinary journal focusing on sustainable chemistry.
“To make greener chemicals and fuel, we’re working with plant material, but we don’t want to compete with its food value,” Saha said. “So instead of taking corn and extracting its sugars to make ethanol, we’re making use of the stalks and cobs left over after the corn is harvested, as well as other kinds of waste like wood chips and rice hulls.”
“The lignin that makes their cell walls so tough and sturdy acts like superglue, holding tightly to the sugars,” Saha said.
Industry currently separates out the sugars from the lignin through a two-step process using harsh chemicals and reaction conditions in the first step, and an expensive enzyme in the second step. This process makes the resulting sugars expensive and the end products, though renewable, less competitive than those produced with petroleum.
The process invented at UD, however, is just one step. It doesn’t require a separate pretreatment step commonly used in biorefineries to disintegrate the lignin from the sugar polymers cellulose and hemicellulose. UD’s one-step technology integrates the pretreatment step and the hydrolysis of cellulose and hemicellulose in one pot and operates at considerably low temperature (85°C) and short reaction time (one hour), which makes the method energy efficient. It’s water efficient, too.
The key to the technology, which has been filed as an international patent application by UD, is the use of a concentrated solution of an inorganic salt in the presence of a small amount of mineral acid. The concentrated salt solution requires a minimal amount of water. The solution swells the particles of wood or other biomass, allowing the solution to interact with the fibers, much like a newspaper swells when water spills on it.
The unique properties of the salt solution make the method very efficient, Saha said, with up to a 95 percent theoretical yield of sugars.
What’s more, the team has integrated the process with another step, called the dehydration reaction, which converts the sugars to furans in the same pot and enables the salt solution to be recycled. Furans are highly versatile compounds used as starting materials for making specialty chemicals. READ MORE
Extracting Sugar from Waste Key to Greener Production (R&D Magazine)
Sustainable solutions a high priority (Innovators Magazine)