Unleaded, diesel or biofuel? This could become the choice at the pump now we can make biofuels that are identical to the petrol we put in our cars, planes and trucks.
Until now, biofuels have been made up of hydrocarbon chains of the wrong size and shape to be truly compatible with most modern engines – they'll work, but only inefficiently, and over time they will corrode the engine.
To be used as a mainstream alternative to fossil fuels – desirable because biofuels are carbon-neutral over their lifetime – engines would have to be redesigned, or an extra processing step employed to convert the fuel into a more usable form.
To try to bypass that, John Love from the University of Exeter in the UK and colleagues took genes from the camphor tree, soil bacteria and blue-green algae and spliced them into DNA from Escherichia coli bacteria. When the modified E. coli were fed glucose, the enzymes they produced converted the sugar into fatty acids and then turned these into hydrocarbons that were chemically and structurally identical to those found in commercial fuel.
"We are biologically producing the fuel that the oil industry makes and sells," says Love.
The team now needs to work out how to scale-up the project to mass-produce hydrocarbons.