A team of British and Finnish scientists have figured out how to make small amounts of propane using Escherichia coli (E. coli), the naturally-occurring, diverse group of bacteria most commonly known for causing food poisoning symptoms when ingested.
The propane, created from a genetically engineered version of the bacterium, is completely renewable and could be ready for commercial production within 10 years, according to the team, which published a study on the discovery Tuesday in the journal Nature Communications. The propane can be used the same way regular propane is used - for furnaces, outdoor grills, and to make liquefied natural gas - except instead of being derived from fossil fuels, it would be derived from a renewable source.
"Although we have only produced tiny amounts so far, the fuel we have produced is ready to be used in an engine straight away," researcher Patrik Jones, the lead author of the study, said in a statement. "This opens up possibilities for future sustainable production of renewable fuels that at first could complement, and thereafter replace fossil fuels like diesel, petrol, natural gas and jet fuel."
E. coli has long been looked at as a bacterium that could be used to make renewable fuel, because of its ability to produce fatty acids. Indeed, conventional biodiesels are comprised of long chain fatty acids, usually derived from vegetable oils or animal fats.
But the bacterium's ability to make fatty acids wasn't enough to make the propane. In order to do that, the scientists from Imperial College in London and the University of Turku in Finland had to take genes from a group of separate enzymes and engineer them into the E. coli. That process eventually "tricked" the bacteria into making propane instead of cell membranes.
Genetically engineered E. coli has already been used along with blue-green algae to make biofuel, though Jones noted to the Guardian that that fuel is "not commercially viable." That's because of the cost of harvesting and processing the algae, Jones said, and the fact that large-scale infrastructure does not currently exist for biofuels.
That's why Jones' team chose to work on propane, he said, because "it can be separated from the natural process with minimal energy and it will be compatible with the existing infrastructure for easy use." It is also easily converted from liquid to gas and back, making it easy to transport.
Jones acknowledges that there are still many steps to take before E. coli-created propane can become commercially viable - most importantly, the current high cost of making the fuel, considering the amount of propane the bacteria can make is only about one thousandth of what would be commercially viable today. "Given the availability and low cost of fossil fuels, a major challenge for all novel renewable fuel production concepts is to achieve economically sustainable well-to-wheel systems," the study reads.
Still, Jones said the fact that his team's research proves that propane can indeed be made from a renewable process is encouraging. The discovery is one step closer to his ultimate goal, which is being able to use the genetically engineered system to convert solar energy into a propane-like chemical fuel.
"At the moment, we don't have a full grasp of exactly how the fuel molecules are made, so we are now trying to find out exactly how this process unfolds," he said. "I hope that over the next 5 to 10 years we will be able to achieve commercially viable processes that will sustainably fuel our energy demands."
By. Emily Atkin of Climate Progress
Joe Romm is a Fellow at American Progress and is the editor of Climate Progress, which New York Times columnist Tom Friedman called "the indispensable… More