Researchers in the Franklin College of Arts and Sciences have developed a “super strain” of yeast that can efficiently ferment ethanol from pre-treated pine, one of the most common tree species in Georgia and the U.S. The research could help biofuels replace gasoline as a transportation fuel.
“Companies are interested in producing ethanol from woody biomass such as pine, but it is a notoriously difficult material for fermentations,” said Joy Doran-Peterson, associate professor of microbiology. “The big plus for softwoods, including pine, is that they have a lot of sugar that yeast can use. Yeast are currently used in ethanol production from corn or sugarcane, which are much easier materials for fermentation. Our process increases the amount of ethanol that can be obtained from pine.”
Before the pinewood is fermented with yeast, however, it is pre-treated with heat and chemicals, which help open the wood for enzymes to break the cellulose down into sugars. Once sugars are released, the yeast will convert them to ethanol, but compounds produced during pre-treatment tend to kill even the hardiest industrial strains of yeast, making ethanol production difficult.
Doran-Peterson, along with doctoral candidate G. Matt Hawkins, used directed evolution and adaptation of Saccharomyces cerevisiae, a species of yeast used commonly in industry for production of corn ethanol, to generate the “super” yeast.
Their research, published online in Biotechnology for Biofuels, shows that the pine fermented with the new yeast can successfully withstand the toxic compounds and produce ethanol from higher concentrations of pre-treated pine than previously published.
Pine is an ideal substrate for biofuels not only because of its high sugar content, but also because of its sustainability. The loblolly pine used for this project is among the fastest growing trees in the American South.