By Michael J Coren

Bacteria are miracle workers of molecules. The tiny bioreactors can turn carbon atoms into food. For humans, that's convenient. We use microbes to manufacture everything from antibiotics to vitamins (as well as digest food in our gut), but fuel has always been a priority. Yet cajoling bacteria to efficiently produce fuels in sufficient quantity and purity has proved difficult.

Researchers at MIT have moved us one step closer to that goal by redirecting a soil bacteria's tendency to store up energy when stressed into producing a high-octane fuel known as isobutanol. Known as Ralstonia eutropha, the little microbe turns molecules of carbon from sugar (or other simple molecules) into longer, energy dense polymers. By "knocking out a few genes, inserting a gene from another organism and tinkering with the expression of other genes," MIT researchers were able to turn the bacteria's carbon-storing proclivities into a steady stream of isobutanol.

The energy-dense fuel is a potential replacement for gasoline because it can run in today's engines without modifications (as is required by common biofuels such as ethanol). The next challenge is to get the bugs to chow down on CO2 emissions, similar to those emitted from power plants, which would allow them to create isobutanol directly from fossil fuel emissions. The research appeared in the journal Applied Microbiology and Biotechnology.

MIT's work is part of decades of efforts around the world to develop advanced fuels in bacteria rather than fields (either farm or oil ones). In fact, isobutanol had been produced by fermentation more than a century ago, but techniques to scale the technology have failed. Since microbes' molecular machinery is ideally suited to creating carbon-based biofuels, researchers are trying to redesign their metabolism to make that happen. Soon, synthetic metabolic pathways may turn our microbial friend and foes, even pathogens such as E. Coli, into our future fuel refineries.

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