Berkeley, California – Researchers in California, including those from the U.S. Department of Energy’s Joint BioEnergy Institute, have produced a genetically-engineered plant that could improve biofuel production.
The researchers introduced a corn gene into switchgrass, a non-food plant highly touted as a potential feedstock for advanced biofuels. The gene more than doubles the amount of starch in the plant’s cell walls and makes it much easier to extract polysaccharides and convert them into fermentable sugars that can be synthesized into fuel. The gene keeps the switchgrass in its juvenile phase of development, preventing it from advancing to the adult phase, when it becomes more difficult to extract the polysaccharides.
The modified plant has lower levels of lignin, a tough woody material that locks in the polysaccharides as the plant ages, and higher levels of glucose and other sugars when compared to wild switchgrass.
Lignocellulosic biomass is the most abundant organic material on earth and studies have consistently shown that biofuels derived from it could be produced in the U.S. in a sustainable fashion and replace current gasoline, diesel and jet fuels on a gallon-for-gallon basis. Unlike ethanol made from grains, the fuels would be carbon-neutral and not exacerbate global climate change.
Switchgrass is a perennial grass that is salt- and drought-tolerant, can flourish on marginal cropland, does not compete with food crops, and requires little fertilization. A key to its use in biofuels is making it more digestible to fermentation microbes. The researchers believe that keeping the plants in their juvenile stage should make it easier to break them down into fermentable sugars, and since they don’t make seed, more starch should be available for making biofuels. The corn gene also prevented the switchgrass from flowering even after more than two years of growth, which the researchers said limits the risk of the genetically-modified switchgrass from spreading genes into the wild switchgrass population.