Hybrid pervaporation and salting-out for effective acetone-butanol-ethanol separation from fermentation broth

In this study, hybrid pervaporation/salting-out process was coupled with fed-batch acetone-butanol-ethanol (ABE) fermentation for high-titer solvents production. At the first-stage separation, 18.8 g/L of ethanol, 125.9 g/L of acetone and 199.5 g/L of butanol were obtained in the permeate of pervaporation. Model solution with similar solvents content to the permeate condensate was used for the second-stage salting-out process based on K3PO4 and KH2PO4, respectively. The effect of salting-out factor on ABE concentrations and recoveries in the aqueous and organic phase was compared and optimized. Results indicated that K3PO4 showed better salting-out performance. At the salting-out factor of 1.0, 99.01% of ABE was recovered. Correspondingly, 486.74 g/kg of butanol (805.52 g/kg of total ABE) could be tested in the organic phase. This novel hybrid process was a promising method for biobutanol production and separation.