High-Level Butanol Production from Cassava Starch by a Newly Isolated Clostridium acetobutylicum

A new Clostridium acetobutylicum strain, exhibiting the ability to resist butanol stress and produce butanol, was identified and named GX01. Strain GX01 can use a wide variety of carbohydrates, especially cassava starch, to produce butanol. After the optimization of culture conditions, C. acetobutylicum GX01 could produce 27.3 g/L solvent, including 17.1 g/L butanol, 7.9 g/L acetone, and 2.3 g/L ethanol, from 100 g/L cassava flour and 3 g/L soybean meal. Furthermore, when its acetone-butanol-ethanol (ABE) fermentation was performed in 10- and 30-L bioreactors, the production of total solvent and butanol reached 29.2 and 18.3 g/L, respectively, and 28.8 and 18.8 g/L, respectively. Thus, the high level and stability of butanol production make strain GX01 a promising candidate for ABE fermentation using the low-cost cassava starch.