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Biofuels, Hold The Sugar

Pyrococcus furiosus is one of the extremophiles that could play a key role in developing a new means of producing biofuels. Image courtesy of Dr. Michael W.W. Adams, University of Georgia.

Imagine if we could make biofuels anywhere, without having to worry about biofuel crops competing with food crops. Well, the feds are now funding research that would make that possible.

Modern biofuels are largely made from sugar. Basically, plants (like corn) take energy from the sun to convert carbon dioxide into organic compounds (like sugar) that enable the plants to save the energy for later. We then take the biomass of those plants and ferment the sugars (glucose, fructose, etc.) to create biofuels, such as ethanol and butanol. There are lots of problems with these biofuels though, including the low energy-density of ethanol and the fact that growing crops for biomass can expend a lot of energy – and take resources away from traditional food crops.

But what if we could eliminate the middle stage, cutting out the sugars and fermentation altogether? ARPA-E, the U.S. Department of Energy’s advanced research arm, is now funding a study that aims to create butanol (which packs more energy than ethanol) directly from carbon dioxide and hydrogen. No competition with traditional crops, no fermentation process. Here’s what might make it work: extremophiles.

Extremophiles are microbes that live in extreme environments: extremely salty, extremely acidic, etc. The extremophiles researchers are looking at for this biofuels study live in underwater environments that are extremely hot – between 75 and 100 degrees Celsius (that’s 167 to 212 degrees Fahrenheit, if you’re trying to do the math in your head).

Scientists already know that some of these extremophiles can take carbon dioxide and turn it into a complex molecule called acetyl-CoA – which, in turn, is a biofuel ingredient. ARPA-E’s grant is now allowing researchers to try to push the process a bit futher – by genetically engineering some of these heat-loving microbes to take in carbon dioxide and hydrogen to produce butanol.

It would be pretty cool if it works, since the extremophiles are perfectly happy to work in the dark. That would mean we could make biofuels almost anywhere – underground for instance – and renewable energy wouldn’t have to compete with staple crops for arable land.