Butanol continues to be an important industrial chemical.
Compared to the currently popular fuel additive, ethanol, butanol is more miscible with gasoline and diesel fuel, has a lower vapor pressure, and is less miscible with water, all of which makes it a superior fuel extender. Butanol is currently used as a feedstock chemical in the plastic industry and as a foodgrade extractant in the food and flavor industry. At present, the high recovery costs due to the rather low final concentration of butanol in the fermentation broth is a limiting factor. Such an increase in butanol concentration would significantly help to make this fermentation an economically viable process. Approximately 10 billion lbs of butanol were produced by petrochemical processes in 1989.