E. coli, pink gold? (Image: Steve Gschmeissner/Science Photo Library)

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.

The E. coli were fed on glucose made from plants, but Love reckons that if they were to scale-up, they could tweak the genes to produce enzymes that would allow the bacteria to feed on straw or animal manure. This would mean that land wouldn’t be needed to grow the feedstock that would otherwise be used for food crops – one of the criticisms of biofuels.

Paul Freemont of Imperial College London describes the work as a “beautiful study”. He says it illustrates the potential of using a similar approach for bio-manufacturing not only biofuels but other chemicals we currently source from petroleum, such as those used to make plastics, solvents or detergents.

The work was partly funded by energy company Shell’s research arm.

Journal reference: PNAS, DOI:10.1073/pnas.1215966110