Butanol production in acetone-butanol-ethanol fermentation with in situ product recovery by adsorption

Activated carbon Norit ROW 0.8, zeolite CBV901, and polymeric resins Dowex Optipore L-493 and SD-2 with high specific loadings and partition coefficients were studied for n-butanol adsorption. Adsorption isotherms were found to follow Langmuir model, which can be used to estimate the amount of butanol adsorbed in acetone-butanol-ethanol (ABE) fermentation. In serum-bottle fermentation with in situ adsorption, activated carbon showed the best performance with 21.9 g/L of butanol production. When operated in a fermentor, free-and immobilized-cell fermentations with adsorption produced 31.6 g/L and 54.6 g/L butanol with productivities of 0.30 g/L.h and 0.45 g/L.h, respectively. Thermal desorption produced a condensate containing similar to 167 g/L butanol, which resulted in a highly concentrated butanol solution of similar to 640 g/L after spontaneous phase separation. This in situ product recovery process with activated carbon is energy efficient and can be easily integrated with ABE fermentation for n-butanol production. (C) 2016 Elsevier Ltd. All rights reserved.