bacteria for propane
September 3, 2014

Human Gut Bacteria May One Day Help Fuel Your Car

Eric Hopton for - Your Universe Online

There is one tough little bug living happily in your gut that is both friend and foe in equal measure and if one group of researchers are right it could be a surprise new source of energy.

Escherichia coli, better known as E.coli, is a type of bacteria that loves the environment of the human stomach. In the right balance it is thought to aid digestion, but when it gets too frisky – usually as a result of food poisoning – it can make you seriously ill. E.coli can kill, but it also may help the planet survive the ravages of fossil fuel emissions.

In a “proof of theory” study, scientists at the department of life sciences at Imperial College London have run a series of experiments in which propane gas has been produced from glucose using E.coli. Propane is already widely used as a fuel and drives home heating systems, vehicles and has many other applications. It is the main component of LPG – liquefied natural gas – but until now has only been captured from naturally occurring fossil fuels.

Patrik Jones, the lead author of the study’s report, told The Guardian that the propane they created was chemically identical to that produced from fossil fuels. Propane is potentially an excellent renewable energy source. It has a lower carbon content than traditional fossil fuels and emits 20 percent less greenhouse gases than unleaded petrol. One of the main attractions of propane as a fuel is that it can be liquefied relatively easily without the massive energy requirements of liquefying hydrogen – another gas often promoted as a future renewable energy source.

The Imperial College team used an intriguing method to capture the gas. The human body uses a biological process that turns fatty acids into cell membranes. The experiments involved the use of enzymes (thioesterase, aldehyde-deformylating oxenase, and CAR) to divert the process so that, instead of creating the membranes, propane was produced. The combined action of enzymes and bacteria produced butyric acid, an extremely obnoxious-smelling compound but one which is essential for propane production.

Initial results are promising and the gas produced is completely viable for immediate use in vehicle engines. However, Jones is keen to point out that the amount of propane they managed to produce is tiny and well below commercially marketable levels. To bring investment from big business on board, the researchers will have to prove that the process can be much more efficient.

As the authors of the report say in their summary, this could be part of the next generation of renewable bio-fuels. The E.coli propane production process ticks a lot of boxes in terms of renewability and being a good fit with the infrastructure which already exists for propane itself such as transportation, storage and utilization. There is a huge and growing market already in place for propane. But wholesale use of intestinal bacteria to “grow” fuel is a long way off for now. The scientists behind the work believe it will be 5 to 10 years before it could be commercially available.

The results of the research have been published in the journal Nature Communications.