Jay Keasling and Howard Chou of Lawrence Berkeley National Laboratory and the Joint BioEnergy Institute (JBEI) have invented a fermentation process to produce 5-carbon alcohols from genetically modified E. coli host cells regardless of the feedstock used. This is the first time isopentanol has been synthesized from the isoprenoid pathway. The resulting isopentanol has an energy content of 107.7 megajoule (MJ) per gallon—higher than ethanol (79.4 MJ/gallon) and butanol (102.1 MJ/gallon), and approaching the energy content of gasoline (121.0 MJ/gallon). In addition, isopentanol does not require the use of flexible fuel vehicles or engine modifications.
This technology provides a gasoline replacement that is competitive with other alternative fuel products. Production costs for electricity and water use are lower than those for ethanol because the Berkeley Lab fuel can be processed in a centrifuge or siphoned off rather than distilled. Because the new fuel is less soluble in water than ethanol or butanol, less energy-intensive processes may be required to separate the fuel from the fermentation broth during production. Low water solubility offers further cost advantages by enabling shipment of the fuel in the existing petroleum pipeline infrastructure. Finally, production need not compete with food crops for land and natural resources.
The 5-carbon alcohols produced from the genetically modified host cell are 3-methyl-2-buten-1-ol; 3-methyl-3-buten-1-ol; or 3-methyl-butan-1-ol. These alcohols have the potential to replace up to 100% of the 5-carbon hydrocarbons that comprise as much as 20% of gasoline, thus offering up to a 20% replacement of gasoline.
More info: http://www.lbl.gov/Tech-Transfer/licensing/index.html.
