Breakthrough in Genetically Modified Plants for Renewable Energy

Scientists at The Samuel Roberts Noble Foundation in Ardmore, Oklahoma, have uncovered a gene that could revolutionize the biofuels industry in the United States. The gene is responsible for controlling the density of plant material. By removing the gene, farmers can grow denser plants that produce more biomass from the same acreage. In short, more energy from the same amount of land and less conflict with land needed to grow food.

Huanzhong Wang, Ph.D., a postdoctoral fellow at the foundation, found a gene that controls the production of lignin in the central portions of the stems of Arabidopsis and Medicago truncatula, species commonly used as models for the study of plant genetic processes. Lignin is a compound that helps provide strength to plant cell walls, basically giving the plant the ability to stand upright. When the newly discovered gene is removed, there is a dramatic increase in the production of biomass, including lignin, throughout the stem.

Increasing lignin in non-food crops, such as switchgrass, may increase the density of the biomass and produce more feedstock per plant. Compared to corn- or soybean-based biofuels, switchgrass and other low-input grassland perrenials can provide more usuable energy, greater greenhouse gas reductions, and less agricultural pollution per acre. In addition, many of the grass varieties can be grown on agriculturally degraded land, are drought and salt tolerant, and therefore can be grown on land that is not used for food production. Perrenial grasses also offer an excellent habitat for a wide variety of birds and small mammals.

"In switchgrass, as the plant matures, the stem becomes hollow like bamboo," said Dr. Richard Dixon, director of the Noble Foundation's Plant Biology Division. "Imagine if you use this discovery to fill that hollow portion with lignin. The potential increase in biomass in these new plants could be dramatic. This technology could make plants better suited to serve as renewable energy sources or as renewable feedstocks to produce advanced composite materials that consumers depend on every day."

Collaboration with scientists at the University of Georgia revealed that removing the gene also increases the production of carbohydrate-rich cellulose and hemicellulose material in portions of the plant stem. These are the components of a plant that are converted to sugars to create advanced biofuels, such as cellulosic-derived ethanol or butanol. More celluloses and hemicelluloses mean more sugars to use for carbohydrate-based energy production.

Biofuels have already shown that they can help even a large nation wean itself from foreign oil. Brazil has eliminated its dependence on foreign oil by using ethanol from sugar cane to meet most of its fuel needs. Increased lignin production in switchgrass and other perennial grasses could help the US reach energy independence as well.

John Howley
Woodbridge, New Jersey