A team of researchers from the University of Wisconsin-Madison have figured out how to get the the sugar molecules trapped inside inedible plant biomass, a key step in the creation of cellulosic biofuels.
This press release from the school says the process, featured in the latest issue of the Proceedings of the National Academy of Sciences, converts up to three-quarters of the sugars locked up in raw corn stover into simple, fermentable sugars … an attractive alternative to the enzyme-based approaches currently favored by biofuels researchers:
“Our chemical process is extremely efficient,” says Ron Raines, a UW-Madison professor of biochemistry and chemistry. “It also has marked advantages over the existing processes-both chemical or enzymatic-for producing sugars from biomass.”
Working under a strong federal mandate, scientists across the nation are developing next-generation biofuels from inedible plant materials such as corn stover, switchgrass and wood chips. Unlike most ethanol on the market today, these so-called cellulosic biofuels would not be derived from food sources, potentially reducing the stress on food systems. But the complex structure of plant material keeps cellulose’s energy-rich sugars locked up in tangled webs, making the process of converting it to fuel difficult. In recent years, scientists have been trying to find and engineer enzymes that can break down the sugars more efficiently, potentially opening the door to the commercial production of fuel from cellulose.
Raines’ chemical approach, which he developed with graduate student Joe Binder, a doctoral candidate in the chemistry department, on the other hand, relies on a mixture of an ionic liquid and dilute acid-both of which can slip past lignin-to dissolve the long chains of sugars in biomass and break them up into individual molecules of glucose and xylose.
The article goes on to say that the researchers were able to get about the same amount of sugar out of the biomass as the more-expensive enzymes usually used. This could significantly cut the cost of cellulosic ethanol, helping move that industry forward.