Engineering Escherichia Coli For Production Of N-Butanol


The rise in global energy usage the disappearance of fossil fuel reserves and the need for carbon-neutral fuels has highlighted the importance of developing technologies to harness new and renewable energy sources. Liquid fuels derived from plant biomass are being explored as potential gasoline and diesel substitutes. The major biofuel in use today is ethanol which can be blended with gasoline for use in conventional engines. But ethanol has a low energy return compared with gasoline high vaporizability and is miscible with water. Alternative biofuels such as n-butanol have characteristics that are closer to gasoline and could perform better as a replacement. Although many microorganisms are capable of producing ethanol as a fermentation product few are able to produce butanol. The microbes that do produce butanol are not as easily manipulated genetically nor offer as robust hosts for fermentation as E. coli or S. cerevisiae. Researchers at UC Berkeley have constructed a biosynthetic pathway for butanol with genes obtained from various host organisms and demonstrated its activity in E. coli.


1) Production of n-butanol in microbes without native pathway. 2) Biosynthetic pathway can be introduced into E. coli or yeast for ready fermentation of n-butanol. 3) Metabolic pathways of these organisms can be readily modified to further improve yield and efficiency. 4) Ability to combine metabolic steps from aerobic and fermentative metabolic steps to increase productivity without disrupting native metabolic functions.

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