Bioenergy: Harnessing Microbial Power
There is a growing awareness that the world's reliance on energy from nonrenewable fossil fuels is not sustainable. It is projected that U.S. energy demand will increase by more than 50% by 2025, and our dependence on fossil fuels puts us at risk of disturbances in energy supply due to changing political climates and international relations. Additionally, the greenhouse gas emissions that result from burning fossil fuels are widely believed to be a primary cause of global warming. All of these factors make finding renewable, environmentally friendly fuels a major priority for America—and the world.
Ethanol and Microbial Communities
One emerging energy source is ethanol (grain alcohol)—a high-octane biofuel derived from corn, sugarcane, or other agricultural sources. Cellulosic ethanol is made from the cellulose found in such common agricultural wastes as corn fiber, corn stalks, wheat straw, and other biomass like switchgrass and miscanthus. But the process that converts the cellulose from agricultural waste into usable ethanol depends on one essential ingredient: microbial communities. First, several types of microorganisms must work in concert to transform the cellulose from agricultural wastes into sugars. Then, the sugars are fermented—also by microbes—to produce ethanol.
Bacterial Products
Still other microbes produce a variety of potential energy sources including hydrogen, methane, butanol, and even electric current. By carefully manipulating the availability of nutrients and other environmental conditions, scientists are working to develop ways to capture and store the useful by-products of such microbes. 
But much more needs to be known about how these microbial communities function before we can control and channel the energy sources they produce. Metagenomics offers an important means of achieving this knowledge and should be considered a part of America's strategic approach to addressing present and future needs for renewable energy sources.
The information on this Web page was derived from the National Research Council report The New Science of Metagenomics: Revealing the Secrets of Our Microbial Planet (2007) and the 20-page educational booklet derived from that report, Understanding Our Microbial Planet: The New Science of Metagenomics.
PHOTO CREDITS: Photo of scientist displaying seedlings and photo of technicians adding starter microbes to a bioreactor courtesy of Keith Weller, USDA.
Support for this web publication was provided by the Presidents' Circle Communication Initiative of the National Academies.
