DOE reports the first one-pot, wash-free process for ionic liquid pretreatment and saccharification of switchgrass

August 21, 2013

Researchers with the U.S. Department of Energy’s (DOE) Joint BioEnergy Institute (JBEI), a bioenergy research center partnered with DOE’s Bioenergy Technologies Office, have reported the first demonstration of a one-pot, wash-free process for the ionic liquid pretreatment and saccharification of switchgrass. 

Using an imidazolium-based ionic liquid pretreatment, a team from Sandia National Laboratories was able to release high concentrations of two sugars essential to creating biofuels, glucose and xylose. They were then able to separate the sugars at better than 90% efficiency, vastly improving costs and allowing the ionic liquid mixture to be recycled and reused. 

“By combining ionic liquid pretreatment and saccharification into a single vessel, we eliminate the excessive use of water and waste disposal currently associated with washing biomass that is pretreated with ionic liquids,” says chemical engineer Blake Simmons, who heads JBEI’s Deconstruction Division.

Advanced biofuels made from cellulosic sugars stored in grasses and other non-food crops and agricultural waste could substantially reduce the use of the fossil fuels responsible for the release of nearly nine billion metric tons of excess carbon into the atmosphere each year. More than a billion tons of biomass is produced annually in the United States alone, and fuels from this biomass are clean, green, and renewable substitutes for gasoline, diesel, and jet fuel on a gallon-for-gallon basis.

Simmons and his deconstruction team are in the process of further optimizing their research to improve sugar yields, and they are seeking to identify other ionic liquids that are even easier on hydrolyzing enzymes than the imidazolium-based molten salts. For more information, read the press release from team partner Los Alamos National Laboratory.