UW-Madison team develops high-yield non-enzymatic process for production of sugars from biomass using GVL
Researchers at the University of Wisconsin-Madison, led by Dr. James Dumesic, have developed a process for for the non-enzymatic production of sugars from biomass using γ-valerolactone (GVL) itself derived from biomass. A paper on their work, which was funded by the National Science Foundation and the US Department of Energy’s Great Lakes Bioenergy Research Center (GLBRC), is published in the journal Science.
Using a solvent mixture of biomass-derived GVL, water, and dilute acid (0.05 weight percent H2SO4), they produced soluble carbohydrates from corn stover, hardwood, and softwood at high yields (70 to 90%) at laboratory scale. The sugars can then be chemically or biologically upgraded into biofuels. With support from the Wisconsin Alumni Research Foundation (WARF), the team will begin scaling up the process later this year.
GVL promotes thermocatalytic saccharification through complete solubilization of the biomass, including the lignin fraction. The carbohydrates can be recovered and concentrated (up to 127 grams per liter) by extraction from GVL into an aqueous phase by addition of NaCl or liquid CO2. This strategy is well suited for catalytic upgrading to furans or fermentative upgrading to ethanol at high titers and near theoretical yield. We estimate through preliminary techno-economic modeling that the overall process could be cost-competitive for ethanol production, with biomass pretreatment followed by enzymatic hydrolysis.—Luterbacher et al.
To demonstrate the economic viability of this advance, the team needed to concentrate the sugar, remove the GVL for reuse, and show that yeast could successfully generate ethanol from the sugar stream.
Showing that removing and recycling GVL can be done easily, with a low-energy separation step, is a little more of an achievement. By feeding the resulting sugar solution to microorganisms, we proved we weren’t producing some weird chemical byproducts that would kill the yeast, and that we were taking out enough GVL to make it nontoxic. What’s neat is that we can use additives to make the solution separate. It becomes like oil and vinegar.—Jeremy Luterbacher, lead author
An initial economic assessment of the process has indicated the technology could produce ethanol at a cost savings of roughly 10% when compared with current state-of-the-art technologies.
For the past several years, James Dumesic, Steenbock Professor and Michel Boudart Professor of Chemical and Biological Engineering at UW-Madison, and his research group have studied the production of GVL from biomass, and in more recent work they explored the use of GVL as a solvent for the conversion of biomass to furan chemicals. (Earlier post.)
Because GVL is created from the plant material, it’s both renewable and more affordable than conversion methods requiring expensive chemicals or enzymes. This research has contributed new knowledge to the biofuels landscape, resulted in four patent applications, and gained recognition for GVL’s commercial potential from WARF’s Accelerator Program. This program helps license high potential technologies more rapidly by addressing specific technical hurdles with targeted funding and expert advice from seasoned business mentors in related fields.
Under the Accelerator Program effort, Dumesic will serve as principal investigator for an 18-month project involving construction of a high-efficiency biomass reactor. The reactor will use GVL to produce concentrated streams of high-value sugars and intact lignin solids.
Carbohydrates and lignin from the reactor will be delivered to scientific collaborators, including fellow GLBRC investigators, who will optimize strategies for converting the materials into valuable chemicals and fuels.
We’re excited by the team’s scientific achievements and we look forward to supporting the project’s next steps through the Accelerator Program. If the project successfully achieves the anticipated cost reductions for production of the sugars, lignin and ethanol, we anticipate significant commercial interest in this novel process.—Leigh Cagan, WARF’s chief technology commercialization officer
Jeremy S. Luterbacher, Jacqueline M. Rand, David Martin Alonso, Jeehoon Han, J. Tyler Youngquist, Christos T. Maravelias, Brian F. Pfleger, and James A. Dumesic (2014) “Nonenzymatic Sugar Production from Biomass Using Biomass-Derived γ-Valerolactone,” Science 343 (6168), 277-280. doi: 10.1126/science.1246748