Updated fermentation process may boost biofuel production
11/9/2012 4:05 PM EST
SAN FRANCISCO—A fermentation technique used during World War I to make cordite—the explosive propellant that replaced gunpowder in bullets and artillery shells—could find a new use in the production of advanced biofuels, according to researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory.
The researchers report that by adding a new metal catalyst to the technique they have shown that the production of acetone, butanol and ethanol from lignocellulosic biomass could be selectively upgraded to the high volume production of gasoline, diesel or jet fuel.
Using the bacterium Clostridium acetobutylicum, the Berkeley Lab researchers fermented the sugars found in biomass into the solvent acetone and the alcohols butanol and ethanol, collectively known as "ABE" products. They then catalyzed these low carbon number products with the transition metal palladium into higher-molecular-mass hydrocarbons that are possible precursors to the three major transportation fuel molecules.
Clostridium acetobutylicum can ferment the sugars found in biomass into the solvent acetone and the alcohols butanol and ethanol.
Source: Berkeley Lab
The specific type of fuel molecule produced—whether a precursor to gasoline, diesel or jet – was determined by the amount of time the ABE products resided with the palladium catalyst, according to Berkeley Lab.
"By catalytically upgrading ABE fermentation products we're able to exploit highly efficient metabolic pathways and achieve near theoretical yields of transportation fuel precursors," said Dean Toste, a chemist who holds joint appointments with Berkeley Lab and the University of California Berkeley. "With our technique, we can obtain about a gallon of fuel from 16 pounds of the sugars that can be derived from lignocellulosic biomass."
Toste is the corresponding author of a paper published in the journal Nature, titled, "Integration of chemical catalysis with extractive fermentation to produce fuels."