New Biofuel Manufacturing Process Could Revolutionize Alcohol as a Fuel

Currently, the primary alcohol being produced for energy purposes is ethanol. A new method for producing longer-chain alcohols as biofuels has been developed by University of California, Los Angeles researchers that shows promise at creating alcohols with an energy content close to that of gasoline. The research paper can be found in the January 3, 2008 edition of the journal Nature.

There are three primary drawbacks with ethanol as a fuel source. First, the energy content of ethanol is substantially lower than gasoline and diesel fuels produced from hydrocarbon distillation. Ethanol is much more corrosive than either of the standard hydrocarbon fuels because of its tendency to readily absorb water. Lastly, ethanol is more volatile than gasoline and diesel fuel, and readily evaporates at much lower temperatures making it harder to transport.

Longer chained alcohols, such as isobutanol or C5 alcohols (alcohol molecules with five branches in the chain) do not share those drawbacks.

The benefits of switching to long chain alcohols over ethanol have long-been known - but production of long chained alcohols in significant quantities has eluded chemical engineers. Standard fermentation practices only produce minute quantities of these forms of alcohol, which are usually highly toxic at the cellular level of bacteria and yeast. Through a genetic modification of the process in E. coli bacteria, the team at UCLA bypassed these problems.

Principal researcher James Liao said "These alcohols are typically trace byproducts in fermentation," In a press release from UCLA. "We bypassed this difficulty by leveraging the native metabolic networks in E. coli but altered its intracellular chemistry using genetic engineering to produce these alcohols."

With this new development already licensed to Gevo, Inc. of Pasadena, California, the future looks bright for this technology to reach broad use.

"These results mean that these unusual alcohols in fact can be manufactured as efficiently as what evolved in nature for ethanol. Therefore, we now can explore these unusual alcohols as biofuels and are not bound by what nature has given us," Liao said.

Patrick Gruber, CEO of Gevo, shares Liao's sentiment. "This discovery leads to new opportunities for advanced biofuel development," Gruber said. "As the exclusive licensee of this technology, we can further our national interests in developing advanced renewable resource-based fuels that will help address the issues of climate change and future energy needs while creating a significant competitive advantage."

The research was supported in part by the UCLA-Department of Energy Institute for Genomics and Proteomics and the UCLA-NASA Institute for Cell Mimetic Space Exploration. Co-authors on the paper are postdoctoral fellow Shota Atsumi and visiting professor Taizo Hanai.