While ionic liquids (paired-ions salts that are liquid at room temperature) show great promise for liberating fermentable sugars from lignocellulose and improving advanced-biofuel economics, an even more promising candidate is now on the horizon—“bionic” liquids.
The current “standard,” imidazolium-based ionic liquids, effectively and efficiently deconstruct biomass into fuel sugars, but are expensive, and thus limited in industrial deployment. They’re also made from nonrenewable sources such as petroleum or natural gas.
“What if we could turn what is now a bane to the bioenergy industry into a boon?” asked Blake Simmons (manager of Sandia’s Advanced Biomanufacturing Group). “Lignin is viewed as a waste stream that is typically burned to generate heat and electricity for the biorefinery….Our bionic liquid concept opens the door to realizing a closed-loop process for future lignocellulosic biorefineries, and has far-reaching economic impacts for other ionic liquid-based process technologies.”
Bionic liquids are tertiary amine-based ionic liquids biologically derived from lignin and hemicellulose. Simmons and Seema Singh (in Sandia’s Biomass Science & Conversion Technology Dept.) are the corresponding authors of, “Efficient biomass pretreatment using ionic liquids derived from lignin and hemicellulose” in the Proceedings of the National Academy of Sciences. Using these abundant, inexpensive polymers (byproducts from the agricultural industry, biofuel plants, and pulp mills) allows for a closed-loop biorefinery: waste-stream lignin can be reused to make more bionic liquid. The Joint BioEnergy Institute (JBEI) researchers tested the effectiveness of their bionic liquids as a pretreatment for biomass deconstruction of switchgrass, one of the leading potential crops for making liquid transportation fuels.
After 73 hours of incubation with these new bionic liquids, sugar yields were between 90% and 95% for glucose, and between 70% and 75% for xylose. These yields are comparable to the yields obtained after pretreatment with the best-performing imidazolium-based ionic liquids and establish an important foundation for the further study of bionic liquids in biofuels as well as other industrial applications.
Read the JBEI news release.