Corn—Switchgrass Biofuel
Monday, December 12, 2011 at 8:01AM | Biofuels Get Help: Switchgrass Meets Corn
Lignocellulosic Biomass
For many experts, advanced biofuels made from plants, specifically lignocellulosic biomass, are the most promising fuels for our future. As an alternative to petroleum-based liquids, biofuels are clean, green, renewable, and a domestic source of transportation energy. In fact, studies show that fuel could be derived from lignocellulosic biomass and sustainably grown in the United States, replacing the dependence on our foreign petroleum-based transportation fuels. Mother Nature, however, makes the breakdown of these plants and the extraction of the necessary sugars a challenge.
Grains are an exception. Their starch sugars are easily released, unlike the complex polysaccharides that are locked within the lignin, a tough woody material found within the walls of a plant cell. For advanced biofuels to be economically competitive, scientists need to find cheap ways of releasing the polysaccharides from their prisons and reducing them to fermentable sugars that can be synthesized into fuel. And that’s exactly what the corn gene is doing for the first part of the process.
Switchgrass
For years switchgrass has been highly touted by scientists as a source of biofuel. It offers a number of advantages over other plant feedstock. It’s drought resistant and grows year-round. It doesn’t compete with cropland and can be grown in marginal soil. It’s tough and hardy and requires little fertilization. The challenge lies in extracting its sugars.
Scientists at the Department of Energy’s Joint BioEnergy Institute (JBEI) coupled with the U.S. Department of Agriculture’s Agriculture Research Service (ARS) introduced the maize (corn) gene to switchgrass in the hopes that it would lessen the amount of lignin in the cell walls of the switchgrass plant. And that’s precisely what happened. The added gene doubled the starch in the cell walls and made it easier for the scientists to extract.
Corn Gene
On a cellular level, the corn gene makes the switchgrass plant believe it’s in a juvenile state. This translates into less lignin being released, as well as prevents the plant from producing flowering. As a result, more sugars are retained within the plant, and seeds aren’t released to contaminate the native plant population.
"We show that Cg1 switchgrass biomass is easier for enzymes to break down and also releases more glucose during saccharification," says Blake Simmons, a chemical engineer who heads JBEI's Deconstruction Division and was one of the principal investigators for this research. When compared to wild switchgrass, lignin levels were down and glucose levels higher.
An added bonus to switchgrass fuel is that it’s carbon neutral, so it doesn’t contribute to global climate change unlike corn-derived ethanol fuels. This means that the moment your garage doors swing open until you reach your destination, the switchgrass-corn partnership will ensure that your fuel is clean and sustainable with no increase to your carbon footprint. It’s a match made in environmental heaven.
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Chris Keenan is a green and general blog writer. He writes for many sites including Precision Garage Door. Chris also maintains a personal house and garden blog.






