BACKGROUND: Microbial production of 2,3-butanediol (2,3-BD) with different substrates and organisms results in various 2,3-BD concentration in fermentation broths. The salting-out of 2,3-BD from different aqueous solutions with different solute content by four high-solubility salts (K 4 P 2 O 7 •3H 2 O, K 2 HPO 4 •3H 2 O, K 2 CO 3 , K 3 PO 4 •3H 2 O) were investigated at 298.15 K.
RESULTS:The distribution coefficient and selectivity coefficient of 2,3-BD were greatly affected by the salt composition and the initial salt concentration, but influenced by the solute content slightly. When the initial K 4 P 2 O 7 concentration was higher than or equal to 550 g kg −1 , 100% of 2,3-BD from the aqueous solutions was recovered, and more than 97.5% of water was removed.
CONCLUSION:The salting-out effects of four salts on the aqueous 2,3-BD solutions were determined in the following order: K 4 P 2 O 7 >K 3 PO 4 > K 2 HPO 4 >K 2 CO 3 . Moreover, the solubility of 2,3-BD in both phases can be predicted in terms of the initial salt concentration and the solute content. EXPERIMENTAL Materials 2,3-butanediol (2,3-BD) with a purity of 98 wt% was supplied by Shanghai yuanye Bio-Technology Co., Ltd (Shanghai, China). The purity of 2,3-BD was measured through gas chromatography (GC). Potassium pyrophosphate trihydrate J Chem Technol Biotechnol 2017; 92: 122-132 /jctb where M is the molar mass, for K 4 P 2 O 7 , M = 330.33 g mol −1 , for K 2 HPO 4 , M = 174.18 g mol −1 , for K 3 PO 4 , M = 212.27 g mol −1 , for K 2 CO 3 , M =138.21 g mol −1 , 31 is the mass fraction of salt in the J Chem Technol Biotechnol 2017; 92: 122-132
