Better Bugs for Making Butanol

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Gevo, a biofuels startup based in Pasadena, CA, has acquired an exclusive license to commercialize Liao's technology. (Liao is on the company's scientific advisory board.) "It's a real breakthrough," says Mathew Peters, Gevo's chief scientific officer. Not only did Liao improve the efficiency of the process, but he also designed his microbes to produce a particular form of butanol called isobutanol. "We believe isobutanol is a superior fuel," says Peters. Compared with 1-butanol, isobutanol has a higher octane number, which reduces knocking in the vehicle's engine.

What's more, the biochemical pathway Liao designed for making isobutanol can be transferred to other microbes. In addition to investigating E. coli, Gevo is looking at different microorganisms that could be modified in the same way. "We're interested in any organism that will make the process cheaper," says Peters.

Gevo isn't alone in its pursuit of a better butanol-producing bug. In June 2006, BP and DuPont joined efforts to develop butanol. .

Last June, BP and DuPont, along with Associated British Foods, announced their plans to build a biobutanol pilot plant at an existing BP site in England. The plant, which will use sugar beet as a feedstock, is expected to begin operations in 2009, with the ultimate goal of commercializing butanol after 2010.

According to Peters, Gevo plans to make a decision by the end of the year on whether to go ahead with its own plans to build a butanol plant. In the meantime, certain technological hurdles still need to be overcome to make butanol cost competitive, he says. Mainly, the microbes need to get faster at producing butanol, and their tolerance to isobutanol, which is toxic to the organisms, must improve. Still, Peters expects Gevo to resolve these issues in the coming months.