Hydrocarbons, such as oil and gas, are chains of carbon atoms with hydrogen atoms attached.
They come in a variety of lengths and shapes. Gasoline chains can be as much as 12 carbons long.
Biofuels on the other hand are alcohols. Corn biofuel is mostly ethanol, which is only two carbon atoms linked together.
Ethanol and other biofuels are good immediate solutions for now, but they require a lot of processing. Most are the wrong size and shape to work well with most modern engines, and they will corrode engines over time. Hydrocarbons such as ethanol also contain 30 percent less energy per gallon than gasoline.
E. Coli By The Gallon
But bacteria fuel is more efficient than other biofuels.
Ideally, biofuels should be chemically identical to the fossil fuels we need to replace, which include hydrocarbons of various lengths. To accomplish this, scientists from the University of Exeter started with common bacteria, E. coli. Then they took genes from the camphor tree, soil bacteria, and blue‑green algae and spliced them into the DNA of the E. coli. These genes make enzymes that convert fatty acids that bacteria normally produce into hydrocarbons chemically identical to those in commercial fuel.
They are going to need millions of vats of bacteria to make enough gasoline. But maybe someday you'll be able to choose regular, diesel, or E. coli at the pump.