Application of Microfiltration for Improved Productivity in Continuous Acetone-Butanol Fermentation

Abstract

The maximum of butanol concentration (11.1-11.3 g/L) was obtained after 72 hours of batch fermentation of Clostidium acetobutylicum (ATCC824) at 35ºC, pH=4.5 – 4.8 using tapioca at 50 g/L sugar concentration as a raw material. The solvent productivity can be then increased considerably by improved process strategies. From continuous with cell recycling fermentation using enzyme hydrolysate of tapioca as a raw material, the productivity was 28 times higher than that of the batch process. The maximal solvent productivity (6.94 g/Lhr^-1) was achieved from the continuous with cell recycling process at 52 g/L feeding glucose concentration and a dilution rate of 0.4 hr^-1. The total solvent concentration was 17.36 g/L (with 9.89 g/L butanol) and the total solvent conversion yield was 0.36.