Butanol is an alcohol that can be used as a transport fuel. It is a higher member of the series of straight chain alcohols with each molecule of butanol (C4H10O) containing four carbon atoms rather than two as in ethanol.Butanol was tradionally produced by ABE fermentation - the anaerobic conversion of carbohydrates by strains of Clostridium into acetone, butanol and ethanol. However, cost issues, the relatively low-yield and sluggish fermentations, as well as problems caused by end product inhibition and phage infections, meant that ABE butanol could not compete on a commercial scale with butanol produced synthetically and almost all ABE production ceased as the petrochemical industry evolved.