The removal of solid impurities and separation of target products from a fermentation broth is becoming more tedious with the utilization of lignocelluloses as source of substrate.2

3-Butanediol

an important chemical used widely is also a main product of sugar-based fermentation carried out by

Klebsiella pneumoniae

.In this study

we investigated the use of salting-out extraction(SOE) that employed a K

2

HPO

4

/ethanol system consisting of 21% ethanol and 17% K

2

HPO

4

(mass fraction) to separate 2

3-butanediol from the viscous Jerusalem artichoke-based fermentation broth.After SOE

about 98% of solid matters was removed

and the viscosity decreased from 72.5 mPa s in the original fermentation broth to 4.4 mPa s in the top phase.The partition coefficient and yield of 2

3-butanediol reached 13.4 and 99%

respectively

and 89% of soluble proteins was removed from the broth.The results showed that SOE is an efficient way for isolating 2

3-BD from a highly viscous fermentation broth by removing much of the solid matters within the broth.