By John Parnell
Scientists have found a way to grow diesel molecules from the E.coli bacteria, commonly known as a bug that can cause food poisoning.
The University of Exeter research, which is being supported by Shell, uses specific strains of the bug to create molecules much closer to regular diesels than the ethanol produced by first generation biofuels.
The process could be used in the future to convert food waste and even sewage into diesel. E.coli turns sugars into oily fats to produce its cell membrane.
By harnessing this process, Professor John Love from the Exeter research team told RTCC it should be possible to eventually produce fuels on a commercial scale.
“The biofuels people are making now are not capable of functioning in a normal engine. Engines have been built around traditional fossil fuels. Modern engines have all sorts of pollution controls and particulate filters so the better the engine the purer the fuel needs to be,” he said.
The E.coli based fuels would circumvent that problem by imitating traditional fuels.
At present large volumes of crops, typically corn or sugar cane, are required to make ethanol based biofuels. This can reduce the climate benefits of using a biofuel rather than a hydrocarbon.
The lab-based E.coli is fed by sugars at the moment but there is potential to find some more sustainable feedstocks.
“You could feed them sugar cane but that’s not what we want,” Love said. “Bacteria can eat anything you give it so potentially we could use waste from food processing, animal manure or even human sewage if issues with viruses could be fixed. We do produce a lot of waste so transferring that into hydrocarbons could be worth considering.”
Birds produce the desired alkane chains of carbon and hydrogen in the wax in their feathers explained Love as do plants, however these waxy chains are typically too long to be used as fuels.
The group has modified the process to create shorter chains that can be used for fuels.
This has the added bonus of making the resultant fuel compatible with existing transport and distribution infrastructure and friendlier to modern car or aviation engines. Ethanol requires its own infrastructure which drives up the price.
“Commercialisation is the goal from Shell’s perspective,” he said. “They’ve provided follow-on-funding for us to start work to increase the yield of the diesel by a factor of 100 to 1000. Shell thinks at that level we could then move on to a pilot plant to assess how the bacteria works at an industrial scale.”
Love estimates a demonstration plant could be 10 years down the line, and warns that before using E.coli on an industrial scale a number of safeguards must be created.
“We have to use different bacteria, that could be deployed in an industrial setting and we have to make sure that if there was an accident or a rupture, the bugs can’t survive in a natural setting so we have to disable them.
“There’s still a few bits of the jigsaw to work on.”