A preliminary study of sugaring-out extraction coupled with ethanol fermentation for separating ethanol from fermentation broth

Abstract

In order to solve the high energy consumption of fuel ethanol production and wastewater treatment, a new technology of sugaring-out ethanol extraction from broth coupled with ethanol fermentation using raffinate phase was presented. Ethanol recovery reached 70% in both simulated ethanol fermentation broth and actual broth using one time sugaring-out extraction, while the initial concentrations of glucose, butanol and ammonium sulfate were 10%, 30%, and 2%, respectively. The influence of raffinate phase on ethanol fermentation was also investigated, and its showed that after butanol concentration decreased to 6.5 g/L by CO2 stripping of raffinate phase, the raffinate phase could be recycled as backset. Along with the increase of raffinated phase cycle numbers, ethanol fermentation time, ethanol concentration and yield were prolonged and decreased, which indicated that sugaring-out ethanol extraction from broth coupled with ethanol fermentation need to be further improved.