For the first time, researchers at the UCLA Henry Samueli School of Engineering and Applied Science have successfully pushed nature beyond its limits by genetically modifying Escherichia coli, a bacterium often associated with food poisoning, to produce unusually long-chain alcohols essential in the creation of biofuels.
"Previously, we were able to synthesize long-chain alcohols containing five carbon atoms," said James Liao, UCLA professor of chemical and biomolecular engineering. "We stopped at five carbons at the time because that was what could be naturally achieved. Alcohols were never synthesized beyond five carbons. Now, we've figured out a way to engineer proteins for a whole new pathway in E. coli to produce longer-chain alcohols with up to eight carbon atoms."
The new protein and metabolic engineering method developed by Liao and his research team is detailed in the Dec. 30 issue of Proceedings of the National Academy of Sciences. The paper is currently available online.
Longer-chain alcohols, with five or more carbon atoms, pack more energy into a smaller space and are easier to separate from water, making them less volatile and corrosive than the commercially available biofuel ethanol. The greater the number of carbon atoms, the higher the density of the biofuel. Ethanol, most commonly made from corn or sugarcane, contains only two carbon atoms.
If we can solve part of our problem with dwindling oil reserves by using biomass it is my expectation that the solution will come from genetic engineering of microorganisms. Small organisms are easier to genetically engineer. Whether the solution will come from genetically engineered bacteria or algae is less clear to me. Bacteria are easier to modify. But algae which can better grow in water might be the better longer term bet. Anyone have any insights on this?
While corn and cellulosic technology have so far favored ethanol the genetically engineered microorganisms will probably be more likely to produce more reduced (having more hydrogens and fewer oxygens) hydrocarbon chains. Diesel might become the most cost effective fuel to produce with a biomass energy approach. So genetically engineered biomass energy microorganisms probably favor increased popularity of diesel engines.
|Share |||Randall Parker, 2008 December 18 11:47 PM Energy Biomass|