For Future of Biofuel, Secret of MPG Ooze Lies in Mutant Bacteria

Scientists are looking way beyond ethanol to a new generation of power—one that's designed on a computer, produced by bacteria and acts just like good old gasoline. The countdown to production-ready designer fuels has begun.

The key to the next generation of biofuels isn't growing in a field; it's mutating in a lab. By swapping natural genes in yeast and bacteria for synthetic ones, scientists have tricked the microbes into producing hydrocarbons--creating, in essence, billions of tiny refineries to turn simple sugars into environmentally friendly diesel, gasoline, jet fuel and biocrude.

"We've been making a lot of things using micro-organisms for a long time," says Jim McMillan, biorefining process R&D manager at the National Renewable Energy Laboratory (NREL). "The real breakthrough here, I think, is recognizing that you can get these microbial factories to produce these very high-energy fuel molecules, like hydrocarbons."

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Moonshine, penicillin, even certain cheeses all rely on millions of similar little helpers. But recent advances in genetics have allowed researchers to design genes on computers and splice them into a microbe's DNA, no longer simply refining the natural abilities of microorganisms, but creating in them new talents entirely.

"Essentially, we take what would normally be converted into triethylglycerides--effectively, fats--and divert that off into these hydrocarbons that we care about," says Greg Pal, a senior director at LS9 in San Francisco, which hopes to bring bacterial diesel fuel to commercial scale by 2011.

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Amidst increasing criticisms of ethanol's shortcomings--lower energy density, energy-intensive production and distillation, and the inability to transport the fuel within existing pipelines--a growing handful of companies are betting that the biofuels of the future will look almost identical to the petroleum-based fuels of the present.

"It's getting easier and easier, but it still takes a decent amount of effort to engineer a biological system into doing something that you want it to do," says Neil Renninger, co-founder of four-year-old Amyris Biotechnologies, a company that previously engineered microbes to churn out inexpensive antimalarial drugs. "So before going down the route of engineering a bug to make a biofuel, we wanted to make sure we were making the best biofuel possible."

Amyris first studied the highest performing compounds of diesel, gasoline and jet fuel, then tinkered with the genetic structures of E. coli and yeast to produce bioequivalents, Renninger says, leveraging the same cutting-edge technology previously employed to produce pharmaceutical-quality medicines at commodity-level prices. The company recently announced a deal with the Brazilian sugar and ethanol manufacturer Crystalsev to launch a joint facility south of São Paulo, giving Amyris access to 2 million tons of sugar to feed its mutated strains of yeast. It projects commercial production of some 30 million gallons of diesel as early as 2010, with production of gasoline and jet fuel roughly one and two years behind, respectively.

LS9 plans to open a pilot facility this summer and a 50- to 100-million-gallon plant three years later, producing a drop-in replacement for diesel, as well as a biocrude to be processed in traditional refineries. Rogue scientist J. Craig Venter, who helped lead an international consortium of scientists to map the human genome, has announced plans to engineer bacteria able to create hydrocarbons not just from sugars, but from CO2 pulled straight from the atmosphere.

"If you look at where sugar cane is in Brazil, or at where biomass will be here in the near future, we're pretty confident that we can compete with oil around the $50-a-barrel range," Pal says. "The key driver of the cost really is the cost of raw materials."

For the moment, microbial hydrocarbons, like ethanol, rely on an inexpensive supply of simple sugars to convert into fuel. In the United States, that supply has traditionally come from the starches found in corn kernels, a feedstock with questionable environmental benefits and marginal economic ones. Until technologies exist to easily derive sugars from tough cellulosic material, such as corn's remaining stalks, leaves and cobs, companies like LS9 and Amyris are likely to feed their fuels with sugar cane--a relatively green source of easy-to-use sucrose, albeit one with limited domestic potential.

As the world continues to consume some 150 million gallons of oil every hour, any potentially game-changing solutions will need not only to work, but to work cheaply and at truly massive scales.

"We could be harvesting on a sustainable basis over a billion tons of dry biomass in the United States if we got serious about it, and that would get us somewhere close to 30 percent of our liquid transportation fuels," NREL's McMillan says. "So while sucrose is undoubtedly part of the solution, to really get that huge volume impact, you have to go to those cellulosic feedstocks."