Have you ever looked at a cornfield and wondered "just what are they going to do with all those stalks come harvest?" Without corn to hold up, they could be pretty useless. However, a team of researchers has found a way to break down corn stalks and other biowaste into a series of chemicals that normally can only be derived from petroleum-based fuels.
Lignin is a complex material that makes trees sturdy and cornstalks stand. It reportedly accounts for nearly a third of all the organic carbon in the biosphere, and yet, till now, we really didn't have much of a use for it.
"Lignin is burned as a low-value fuel, but if biofuels are to become a reality, we need to get more value from lignin," researcher Shannon Stahl at the University of Wisconsin-Madison said in a statement.
According to a study recently published in the journal Nature, that's exactly what Stahl and his colleagues aimed for when finding how to break down lignin into important chemical components.
Lignin has been known to contain chains of six-carbon rings called "aromatics."
"Aromatics are used to make many things, from plastic soda bottles to Kevlar to pesticides and pharmaceuticals," Stahl explained. "Today, the aromatics are almost exclusively derived from petroleum. "
But not for long. Stahl and his team say high yields of aromatics may be obtained by exposing lignin to oxygen followed with a acid treatment under mild conditions.
"The oxidation step weakens the links in the lignin [carbon] chains," explained Alireza Rahimi, the first author of the study. "The acid then breaks the links."
This process frees up those aromatics, but Stahl concedes that the chemicals they obtain from their process still require further manipulation before they have real value.
Still, he says that he and his colleagues have a "head start" in making lignin as a key to future biorefineries that would use renewable biomass rather than petroleum to produce fuels or chemicals.