E. coli lives in human intestines, helping us extract vitamin K. Some strains can cause disease. With a little addition of genes from other bacterial species, it can make diesel fuel.
A University of Exeter team has made a strain of E. coli that makes fuel from sugars. It's no ordinary E. coli: it's been genetically modified with DNA from no less than four other kinds of bacteria. Each of the other bacterial species exists in nature and does part of the chemical process that takes a relatively simple carbon molecule (sugar) and turns it into the long-chain ones that go into fuel.
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By putting those genes together in one organism the scientists were able to breed an E. coli strain that makes fuel - or more accurately, chemicals called alkanes and alkenes. Diesel fuel is a mixture of these kinds of carbon compounds. The experiments were published in the Proceedings of the National Academy of Sciences.
This is a big advance in deriving fuel from plants, because the molecules are the same as the ones in the diesel at the pump. There's no need to modify the engine of a car or use odd fuel mixes. In addition, the bacteria produce a more consistent quality of fuel than most processes currently used to make biofuels.
Although burning biodiesel from bacteria still emits carbon dioxide, like any other fuel, carbon dioxide gets taken up by the E. coli as they produce it. That means the net emissions into the atmosphere are much smaller.
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Another big plus is that the E. coli-made fuel doesn't need to use crops of any kind. That eliminates the issue of using food crops to make fuel, and even solves the land and water use problems.
That said, it will still be some time – perhaps a decade - before this is commercialized, if at all. While it looks promising the big challenge will be growing the new E. coli at an industrial scale. But the scientists at Exeter have shown that it can be done, and that ‘s a start.
Credit: Marian Littlejohn / University of Exeter