Two enzymes termites use to break up lignin, a tough plant material that is major problem during cellulosic ethanol production, have been isolated by University of Florida (UF) researchers.
Cellulosic ethanol production often involves genetically engineered microbes such as bacteria or fungi to break down sugars found in the cell walls of plants. Before the microbes can do their work, however, they must first get past lignin.
Lignin molecules are clumped around the sugar molecules, forming a barrier the microbes often can’t penetrate. So the material must first be exposed to heat and steam or caustic acids and bases to break that barrier down. These extra steps make the process much more expensive and often generate hazardous waste.
The Florida researchers have determined that enzymes in termite salivary tissues may be able to accomplish the same task, and at room temperature.
“Once we figure out the best way to integrate this sort of enzyme into the process, it could drop the cost of producing cellulosic ethanol significantly,” says UF entomologist Mike Scharf, who led the research.
The work was a collaboration between UF’s Institute of Food and Agricultural Sciences and Chesapeake-Perl Inc., a biotechnology company. It was funded by the U.S. Department of Energy and The Consortium for Plant Biotechnology Research Inc.
A 2009 report by Sandia National Laboratories predicted that cellulosic ethanol could replace about 30% of the nation’s gasoline by 2030, if production costs can be reduced.
“This is definitive and original research that could realistically be a significant contribution to green energy,” says James Preston, a UF microbiologist who studies enzymes in bacteria that break down plant material. “It’s this kind of work that keeps pushing cellulosic ethanol toward practicality.”
The study follows more than two years of work to identify nearly 7,000 genes associated with the termite gut. The researchers are wading through the genes to identify which ones are associated with enzymes that could be useful.
“We still have a long way to go before we’re finished,” says Scharf. “But, in the meanwhile, we can start putting what we have discovered to good use.”