PROBLEMS CONCERNING LIQUID-LIQUID-EXTRACTION OF EXTRACELLULAR PRODUCTS DIRECTLY FROM FERMENTER BROTHS

The separation of extracellular fermentation products can be accomplis hed by liquid-liquid extraction. The direct extraction of products fro m fermenter broths shows considerable advantages compared with other m ethods, e.g. low product losses, high product concentrations and low f low rates. Additionally, equipment expenditure is low and in-situ extr action can be used as a means of manipulating the fermentation process . However, there are also disadvantages, mainly due to the specific pr operties of fermenter broths. High viscosities and the presence of cel ls affect the hydrodynamic behaviour of the two-phase system in the ex tractor. Other problems arise from the prevention of mass transfer and in the selection of solvents for in-situ extraction