Enhancement of n-butanol production by in situ butanol removal using permeating-heating-gas stripping in acetone-butanol-ethanol fermentation

Butanol recovery from acetone-butanol-ethanol (ABE) fed-batch fermentation using permeating-heating-gas was determined in this study. Fermentation was performed with Clostridium acetobutylicum B3 in a fibrous bed bioreactor and permeating-heating-gas stripping was used to eliminate substrate and product inhibition, which normally restrict ABE production and sugar utilization to below 20. g/L and 60. g/L, respectively. In batch fermentation (without permeating-heating-gas stripping), C. acetobutylicum B3 utilized 60. g/L glucose and produced 19.9. g/L ABE and 12. g/L butanol, while in the integrated process 290. g/L glucose was utilized and 106.27. g/L ABE and 66.09. g/L butanol were produced. The intermittent gas stripping process generated a highly concentrated condensate containing approximately 15% (w/v) butanol, 4% (w/v) acetone, a small amount of ethanol (<1%), and almost no acids, resulting in a highly concentrated butanol solution [~70% (w/v)] after phase separation. Butanol removal by permeating-heating-gas stripping has potential for commercial ABE production.