Microbes tapped as possible fuel source
Scientists have found creatures thriving in places that would poison or cook most life on earth — deep inside rock, under the ocean or in hot springs, places that are extremely salty, or acidic, or bathed in radiation or heavy metals.
Places somewhat like certain industrial operations. The toughness of these bugs — which are types of bacteria or archaea called extremophiles — has long attracted researchers hoping to put them to work in industrial settings such as environmental cleanups or fuel production. The way they thrive in these extreme situations, after all, is by being able to transform substances in ways that most life forms can't.
Now researchers at North Carolina State University and the University of Georgia will try to create their own version of an extremophile, one unlike any found even in the most extreme places — a bug that will create fuels like butanol or ethanol. The bug will be based on an archaea called Pyrococcus furiosus, first discovered near the hot springs of Vulcano Island, Italy, but it will contain features of three to five other bugs.
"The key to our process is this magic organism we're going to try to put together," says Robert Kelly, a professor at NC State and the director of the university's biotechnology program. "It's a pretty far-out idea, but I think it makes some sense."
Kelly is working with Michael W.W. Adams, a biochemistry professor at the University of Georgia who is an expert in microbes that live in places hotter than 100 degrees C, the boiling point of water. Kelly and Adams recently received a $2.7-million US grant through the U.S. Department of Energy's Advanced Research Projects Agency-Energy (ARPA-E) program to build their extreme extremophile.
Most biofuels schemes entail some plant or alga using photosynthesis to create a sugar that is transformed into fuel either by the organism or after the plant is harvested. Corn grows, it is harvested and its sugars are fermented into ethanol.
Kelly's bug would skip the whole photosynthetic sugar-making step. (These bugs are tough. They don't need things like light.) Instead the bug would create liquid fuels directly from hydrogen and carbon dioxide.
The idea is that it would be fed hydrogen and carbon dioxide, derived, perhaps, from natural gas, which has been discovered in great quantities in the U.S. and elsewhere recently. This super-extremophile, using genetic instructions from a few different microbes, would create a complex a molecule called acetyl coenzyme-A, or acetyl co-A for short.
Boon to cities
That's the hard part. From there, it's a relatively easy and well-known process to turn acetyl co-A into a fuel like butanol or ethanol.
One big advantage is that this could be done in the dark, in cities, wherever it's convenient, and wouldn't require farmland or outdoor space, as most biofuels do.
Kelly and Adams are first going to try to assemble the needed metabolic pathways in less extreme bugs like E. coli bacteria. But if they can then get it to work in P. furiosus, they could run the whole system at high temperature, high enough to allow the biofuels produced to be distilled without having to build a separate distilling apparatus.
The difficulties, as Kelly acknowledges, are legion. First the bug has to be created, then it has to perform its tricks in the lab. Hardest of all, it will then have to learn to thrive in an environment even harsher than an Italian volcano: the marketplace.