ABE fermentation gives acetone, butanol, and ethanol in a 3:6:1 ratio, and is used in biofuel synthesis due to the production of ethanol.
Genetic engineering could be used to change the metabolic flux through the pathways, increasing the yield of ethanol, improving the efficiency of the fermentation process. The pathway could be engineered to decrease the presence of enzymes producing acetone and butanol, while upregulating the expression of enzymes synthesising ethanol. De novo protein design could also be used to improve the function of the enzymes involved in producing the desired product. Improving Clostridium tolerance to ethanol and the other products of the pathway would allow higher concentrations to be obtained, increasing yield.