One hundred years of clostridial butanol fermentation.

Butanol has been widely used as an important industrial solvent and feedstock for chemical production. Also, its superior fuel properties compared with ethanol make butanol a good substitute for gasoline. Butanol can be efficiently produced by the genus Clostridium through the acetone-butanol-ethanol (ABE) fermentation, one of the oldest industrial fermentation processes. Butanol production via industrial fermentation has recently gained renewed interests as a potential solution to increasing pressure of climate change and environmental problems by moving away from fossil fuel consumption and moving toward renewable raw materials. Great advances over the last 100 years are now reviving interest in bio-based butanol production. However, several challenges to industrial production of butanol still need to be overcome, such as overall cost competitiveness and development of higher performance strains with greater butanol tolerance. This minireview revisits the past 100 years of remarkable achievements made in fermentation technologies, product recovery processes, and strain development in clostridial butanol fermentation through overcoming major technical hurdles.