Put Down Oil Drill, Pick Up The Test Tube: Making Fuel From Yeast Synthetic biologist Jay Keasling has already taught yeast to make the leading anti-malarial drug. His next project takes the technology a step further, using yeast to turn plant waste into diesel — and maybe gasoline and jet fuel, too.
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Put Down Oil Drill, Pick Up The Test Tube: Making Fuel From Yeast

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Put Down Oil Drill, Pick Up The Test Tube: Making Fuel From Yeast

Put Down Oil Drill, Pick Up The Test Tube: Making Fuel From Yeast

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Yesterday on this program, we heard about a scientist who's trying to capture carbon dioxide from the air. He wants to turn the carbon into energy.


And doing that on a grand scale could help slow the pace of global warming because it would simply be recycling existing carbon dioxide instead of adding more.

MONTAGNE: Today, we'll hear about another innovation aimed at slowing climate change. NPR's Richard Harris caught up with a scientist who's using a powerful technology called synthetic biology, which uses yeast to produce a cleaner form of fuel.

RICHARD HARRIS, BYLINE: With is super-short crew cut and friendly demeanor, Jay Keasling could fit in nicely where he grew up - on a corn farm in Nebraska that's been in his family for generations. But these days, you'll find him in a glistening building in Emeryville, California. And among the many hats he wears is that of a high official at the Lawrence Berkeley National Lab.

JAY KEASLING: I'm associate laboratory director for biosciences, CEO of the Joint BioEnergy Institute, director of the Synthetic Biology Engineering Research Center, oh, and a professor at the University of California, Berkeley.

HARRIS: Not to mention founder of three biotechnology companies.

KEASLING: Well, there's Amyris downstairs, LS9 across the Bay, which also works on biofuels, and then a little startup called Lygos just down the street.

HARRIS: Keasling is one of the central characters in a hot, hot field. The 150 engineers, scientists and technicians here at the Joint BioEnergy Institute are pioneering a technology called synthetic biology. It's genetic engineering taken to a whole new level.

KEASLING: My research since I've been at Berkeley for the last 20 years has been focused on how do you engineer chemistry inside cells? I really believe that you can use microbes as little chemical factories to produce almost anything we want.

HARRIS: Keasling's most successful project to date doesn't have to do with energy. Scientists inserted or tweaked a dozen genes in yeast and turned it into a tiny factory that churns out a synthetic version of a key anti-malarial drug called artemisinin. They licensed that drug to a company called Sanofi.

KEASLING: And Sanofi is now producing a product. In fact, they've produced 35 tons, which is enough for 70 million people. And then the drug will go out to people in the developing world.

HARRIS: You'd think that it would be a huge leap from producing a drug to churning out fuel, but Keasling says actually no. Artemisinin is made up mostly of hydrogen and carbon atoms strung together. It's a hydrocarbon, not so different from diesel fuel. So, they realized this could be an important stepping stone on their quest to come up with a biological fuel.

KEASLING: If we can just make a few more tweaks to that yeast that produces artemisinin, we can get it to spit out diesel fuels, or maybe even jet fuels, or gasoline.

HARRIS: Sure enough, they made those tweaks. Keasling's company, Amyris, scaled it up big-time in Brazil where sugar from sugar cane is cheap.

KEASLING: So, Amyris has a factory in Brazil that's using the engineered yeast, taking in sugar and spitting out a product that's a diesel fuel. And diesel is in buses in Rio and Sao Paulo.

HARRIS: And how much does this diesel cost in Brazil?

KEASLING: Well, this diesel is still more expensive than petroleum-based diesel by quite a long shot.

HARRIS: The yeast produces a hydrocarbon called farnesene, which can not only be converted to diesel but also turned into other much more lucrative chemicals. So, now this is a matter of engineering. How do you drive down the price? One way is to work on a cheaper and more abundant starting material: raw plant matter instead of purified sugar.

KEASLING: It turns out that all plants are roughly two-thirds sugar. It's tied up in a molecule called cellulose.

HARRIS: So, one challenge is to engineer organisms that can break down cellulose to liberate all that sugar. Under ideal circumstances, there's enough of this raw plant material - especially agricultural waste - to supply up to one-third of the liquid fuels we use. That would help reduce the buildup of carbon dioxide in the air, at least a bit. Doug Chapin says if you want to cut back on global emissions, those cleaner fuels will help but they won't do it all.

DOUG CHAPIN: In terms of technology, the big lever is to improve the efficiency of the vehicles.

HARRIS: That's the conclusions of a recent report by the National Research Council. Chapin headed that committee.

CHAPIN: The other big lever is that none of this happens unless the nation has the will to decide that this is the thing they want to achieve almost more importantly than anything else.

HARRIS: We would need to accept fuels that cost more at the pump in exchange for the much less tangible benefit of a healthier planet. Of course, making biofuels cheaper would make that an easier proposition, and that's what drives Jay Keasling.

KEASLING: There are some huge challenges, but there are huge opportunities. Imagine if we replaced a third of our transportation fuels and made them renewable. And maybe through other means we could decrease the use of petroleum-based fuels so that we were putting much less carbon into the atmosphere. That would be a huge benefit.

HARRIS: So, how much of this for you is driven by concern about climate change and how much of this is just a natural evolution of a very cool technology?

KEASLING: I think it's both.

HARRIS: Keasling says there's a personal bonus in this, too. His dad in Nebraska now grows corn for ethanol, which is a very inefficient way to make fuel from crops. Maybe someday he can to switch to a better crop for biofuel. Richard Harris, NPR News.

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