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

•Gas stripping model of ABE from model solutions was characterized.•Integrated fermentation system with gas stripping for in situ butanol recovery.•Fed-batch fermentation with solvent removal at 70°C has been demonstrated.•Permeating–heating–gas stripping greatly enhances butanol productivity and yield. 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 20g/L and 60g/L, respectively. In batch fermentation (without permeating–heating–gas stripping), C. acetobutylicum B3 utilized 60g/L glucose and produced 19.9g/L ABE and 12g/L butanol, while in the integrated process 290g/L glucose was utilized and 106.27g/L ABE and 66.09g/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 (