Biofuel Fermentation by Hyperbutanol-Producing Mutants in Sweet Corn Stalk Juice Medium

Clostridium acetobutylicum parent strain was treated by ultraviolet irradiation at different minutes. The UV treated strains were cultivated in cornmeal medium with butanol added to the medium prior to cultivation. By increasing butanol content gradually in the medium, high butanol tolerance mutants were screened. Results show that mutants by UV treated for 4 minutes display best butanol tolerance and high butanol productivity. With 12g/L butanol added in the medium, the mutants still grow rapidly and accumulated 18.0g/L butanol at the end of 69 hr cultivation. Using sweet corn stalk juice as raw material, the maximum butanol produced by fermentation with the mutants reached 15.3g/L and 18.3g/L in batch and fed-batch fermentation respectively.