Research to Expand Biofuel Sources
Producing Ethanol From Switchgrass, Corn Stover and Poplar Trees
Jul 5, 2007
Today's standard car engines can run efficiently on a fuel ratio of 10 percent ethanol to 90 percent gasoline. However, ethanol still costs more to make than gasoline. And meanwhile, the U.N. and others are noting potential problems with using corn and other food crops for biofuel.
Bioenergy Research Receives Funding
In order to expand renewable biofuels into a larger piece of the energy pie, the United States Departments of Energy and Agriculture have announced they will fund three new bioenergy research centers. These centers will be located at the Oak Ridge National Laboratory, in Oak Ridge, Tennessee; the University of Wisconsin, in Madison; and the Lawrence Berkeley National Laboratory, in Berkeley, California.
Each center will receive $125 million for the next five years. That money will work towards making ethanol production cheaper and more efficient, so that it can compete in the marketplace with petroleum-based fuels.
The research centers will also focus on making fuels from other sources of biomass (see this glossary of biofuels terms). They will study non-food crops, such as poplar trees, switchgrass, and corn stover--the leftover leaves and stems of corn plants. The good thing about these alternative biomass sources is that they can flourish in less-than-ideal spots, leaving the better acreage for food crops.
The downside is that the energy locked into these kinds of biomass is much harder to tap.
Biofuels Research Goes High-Tech
Biomass may seem like a low-tech fuel source, but scientists are using high-tech methods to improve their ability to turn it into affordable biofuels.
With powerful supercomputers, scientists can "watch" 3-D models of microbes break down cellulose and ferment glucose in plant cells. These computers are also helping genetic engineers map the genes of the weedy switchgrass and the easy-to-grow poplar tree.
By studying their genes, the scientists hope to create plants that grow more biomass in less acreage. For example, they are adjusting the proteins in the poplar’s genes to make trees with shorter stems that are easier to harvest., yet with more branches and leaves.
Other researchers are trying to increase the plants' resistance to cold, drought and diseases.
Breaking Up (Cells) is Hard to Do
One of the biggest problems with making fuels from biomass is breaking up the stiff cell walls that give plants their structure. Inside lies the cellulose, a lattice of molecules that includes glucose--the sugar that can be fermented into ethanol. This process takes three steps:
- First, enzymes break up the plant cell wall structure—like a blender chopping up celery stalks.
- Next, tiny microbes grab the cellulose molecules inside and break it into single molecules of glucose.
- Finally, other bacteria ferment the glucose into ethanol.
3-in-1 Biomass Processing
At the new bioenergy research centers, scientists will look for ways to process biomass into ethanol more efficiently. For example, in the next 10 to 15 years, scientists envision biofuel reactors--large cylindrical tanks full of biomass and bacteria--where the biomass goes through all three steps to become ethanol.
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