A new three-year, nearly $1 million Rural Development Biomass Research and Development Grant from the U.S. Department of Agriculture will allow North Carolina State University scientists to test the efficacy of growing genetically modified trees across North Carolina and using them to produce ethanol inexpensively.
The special trees, the brainchild of Dr. Vincent Chiang, professor of forestry and environmental resources at NC State, have shown multiple benefits in greenhouses: They grow faster, have more cellulose and have up to 50 percent less lignin than normal trees. Cellulose is the major structural component of a plant and is chemically converted into ethanol; lignin â€“ the glue that helps hold a tree together â€“ makes extracting cellulose more difficult.
These benefits are important, says Dr. Hasan Jameel, NC State professor of wood and paper science and the principal investigator for the grant, because faster-growing trees that contain easy-to-access cellulose could be more economically viable as a source for ethanol production than other biomass resources.
“The key to success in biofuels is how much biomass you can grow and how quickly,” Jameel says.
The study will place both genetically modified and untransformed Populus trees in numerous sites across the state and evaluate how varied climates, soils and elevations affect tree performance. Simply put, can trees with less lignin survive and thrive in the real world outside of a greenhouse?
“For biofuels production, we’re talking about a rotation length of less than 10 years, not the 15 to 30 years as for other wood products,” says Dr. John King, an NC State associate professor of forestry and environmental resources and the researcher in charge of planting and maintaining the study’s field experiments. “Maybe the reduced lignin content of the wood will be less important for these short growth cycles compared to trees that live for longer periods of time.”
Dr. Hou-Min Chang, NC State professor of wood and paper science, will periodically test the wood composition in both genetically modified and normal trees to compare their chemical and physical characteristics.
The NC State researchers also hope that some of the chemical processes involved in pre-treating the genetically modified tree biomass before it is chemically converted into ethanol become cheaper and “greener.” Rather than using acids, the scientists will experiment with water and other simpler and less harmful compounds to perform the pre-treatment step. Pre-treatment allows enzymes to access the cellulose material, which is essentially a stew of carbohydrates. Carbohydrates are converted into simple sugars like glucose by the enzymes; the simple sugars are then chemically converted into ethanol.
At the end of the project, the NC State researchers will perform an economic analysis to ascertain the manufacturing cost of converting wood into ethanol. NC State’s Dr. Richard Phillips, adjunct professor of wood and paper science, will lead that analysis.
“This could be a big thing for rural areas, especially in North Carolina, where more than 60 percent of rural land is forest,” Jameel says. “There’s no silver bullet to solve the energy problem, but these trees could be an added product for rural communities.”