Gevo, Inc. turns wood into jet fuel (really)

The process to turn wood into jet fuel sounds like half alchemy, half magic. But Gevo, Inc. an Englewood renewable chemicals and biofuels company, calls it science.

And thanks to a recent $5 million grant from the Department Agriculture, it will spend the next five years doing the same.

This isn't the first time the company has made isobutanol (the basics of jet fuel) out of something you could buy at Vitamin Cottage. The company's grant announcement yesterday was quickly followed by the news that it's already contracted to provide jet fuel to the U.S. Air Force, albeit using a different source: corn starch.

"Gevo now has the technology to turn corn starch into isobutanol, and we have been doing so for two years," says Jack Huttner, executive vice president for corporate and public affairs. "This newest project is exciting, but it's not currently our top priority. It will extend our previous research and support a scale-up of our technology."

When it comes to creating jet fuel out of plants, it's important to remember two things: It takes a long time, and it's complicated. Huttner sounds confident in his ability to translate the process in layman's terms, and this confidence lasts almost to the end of his explanation.

Yeast creates ethanol and other side products naturally: That's where wine, beer and spirits come from. The concept's similar with isobutanol. "What we did with out fancy synthetic biology tools is that we turned off all the ethanol pathways inside the yeast organism and turned on more isobutanol pathways. We turned off what we don't want and got it to make more of what we do want. Think of a yeast organism that has all this internal plumbing, and we just turned off all the pipes for ethanol and made all the pipes bigger for isobutanol."

Simple enough. But that yeast has to eat, and it has a particular fondness for sugars -- carbs. Gevo's current plans to use woody biomass will support its technology development so that it can eat the kind of fermentable sugars that come out of said biomass.

This, incidentally, is the most difficult part. In large part, that's because it is the most expensive. And in an industry that depends upon commercial competition, this is the greatest challenge.

"Working off woody biomass is different than working off energy grass," Huttner says. "Wood chips are different enough that you want to optimize the yield to get the most gallons per ton that you can get. Because you're working with living organisms, namely yeast, you want to develop yeast that loves the stuff you're feeding it."

There are two parts to this puzzle, and the yeast part is one that Gevo has already tackled. The other part -- namely the harvesting, collecting and processing of the wood-based biomass material in order to create the fermentable sugars the yeast craves -- requires further research. The grant, named in respect to the Northwest Advanced Renewables Alliance, comes with a five-year timeline, after which we should see the final product: cellulosic jet fuel.

"You can't have electric-powered planes yet, so they have to have liquid fuel," Huttner says. "The only way to get to a renewable jet fuel is to use renewable materials. The significance is that we'll be able to make jet fuel out of renewable bio materials that can be successfully harvested and converted over and over again."

In the meantime, time is of the essence.

"There's a race to get to jet fuel from renewable materials," Huttner says. "There's a route through seed oil, and there's even a company working to produce it through solid waste, but it's about being cost effective. You've been able to make cellulosic ethanol for many years, but the problem is that it costs too much.

"The target is to be competitive with petroleum-derived jet fuel."

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