Which bacterium is used to produce acetone, butanol and ethanol by fermentation?

Clostridium acetobutylicum is used to produce acetone, butanol and ethanol by fermentation.

The bacterium carries out the historically important acetone–butanol–ethanol process, often abbreviated ABE fermentation. It converts carbohydrates such as starch or sugars into a mixture of solvents under oxygen-free conditions.

The process was developed industrially during the early twentieth century, especially through the work of Chaim Weizmann. Acetone from the fermentation became important for explosives production during World War I, while butanol later found uses as an industrial solvent and fuel component.

C. acetobutylicum is an anaerobic, endospore-forming bacterium. Its fermentation typically shifts from acid production to solvent production as conditions change. It should not be confused with C. botulinum, which causes botulism, or with yeast, which commonly produces ethanol and carbon dioxide rather than the classic ABE solvent mixture.