Direct Fermentation of Gelatinized Cassava Starch to Acetone, Butanol, and Ethanol Using Clostridium acetobutylicum Mutant Obtained by Atmospheric and Room Temperature Plasma

The mutant strain designated as ART18, obtained from the wild-type strain Clostridium acetobutylicum PW12 treated by atmospheric and room temperature plasma, showed higher solvent tolerance and butanol production than that of the wild-type strain. The production of butanol was 11.3 +/- 0.5 g/L, 31 % higher than that of the wild-type strain when it was used for acetone, butanol, and ethanol fermentation in P2 medium. Furthermore, the effects of cassava flour concentration, pH regulators, and vitamins on the ABE production were also investigated. The highest butanol production of 15.8 +/- 0.8 g/L and butanol yield (0.31 g/g) were achieved after the above factors were optimized. When acetone, butanol, and ethanol fermentation by ART18 was carried out in a 15-L bioreactor, the butanol production, the productivity of butanol, and the total solvent were 16.3 +/- 0.9, 0.19, and 0.28 g/L(/)h, respectively. These results indicate that ART18 is a promising industrial producer in ABE fermentation.