In a twist on the classic "microbes that turn shit into petrol", researchers at MIT have developed a bacterium that turns carbon dioxide into a direct substitute for gasoline. When deprived of certain nutrients, the soil bacterium Ralstonia eutropha goes into hoarder mode, shoring up its carbon stores in anticipation of leaner times. The complex carbon polymers that the bacteria store happen to be very similar to petroleum-based plastics, a coincidence that wasn't lost on the scientists. By tweaking the microbe's genome and adding genes from other organisms, the team was able to create a bacterium that makes isobutanol rather than plastic. The researchers are currently focusing on figuring how to manipulate the bacteria to use atmospheric carbon dioxide as a source, although it could feasibly be made to use agricultural or municipal waste. As if turning a greenhouse gas back into fuel isn't benefit enough, Ralstonia eutropha, unlike other microbes engineered to produce gas, continually excrete fuel and so don't need to have be destroyed in order to extract the chemical. The scientists hope these microbial factories may one day compete with the ethanol industry as the primarily source of biofuel. Via MIT.