Regular articleBiobutanol recovery from model solutions/fermentation broth using tripotassium phosphate

- ABE from model solutions/fermentation broth was salted out by K3PO4.
- More than 90 wt% of ABE was recovered and more than 99.75% of water was removed.
- Higher solvents level permits the higher recovery of ABE.
- ABE solubility in salt solution showed a linear relation with the molality of K3PO4.
- Salting-out can reduce the energy consumption for the subsequent distillation.

The acetone + 1-butanol + ethanol (ABE) fermentation has a long history but still faces the challenge of enhancing the low ABE concentration to reduce production cost. Nowadays there is an unprecedented resurgence of interest in separation and purification technology to recovery ABE from fermentation broth. Here we describe a simple salting out procedure for extracting ABE fermentation products efficiently from model solutions/fermentation broth by employing tripotassium phosphate (K3PO4). Increasing the K3PO4 content permits the liquid-liquid splits and enables the recovery of ABE. The liquid-liquid equilibria were mainly determined by the K3PO4 content and slightly affected by temperature and original solvents level. The correlation between the solubility of ABE and the molality of K3PO4 demonstrated this. More than 90 wt% of ABE was recovered from the model solutions/fermentation broth and more than 99.75% of water was removed. This study provides a means to reduce the energy demand of the subsequent distillation process for ABE purification.