Functional Solvent Design for Separation of Bioproducts

According to the development of biotechnology，sufficient separation techniques for bioproducts are strongly required。Among several separation techniques，a purification method due to the partition of bioproducts to aqueous two-phase system seems to be one of promising methods because the aqueous system provides a mild condition。To design the optimum solvent condition，the knowledge of phase behavior of the aqueous two-phase system and the partition coefficient of bioproducts is essentially needed.In the present study，the liquid-liquid equilibria of the dextran-polyethylene glycol-water system were measured at 20°C.The present liquid-liquid equilibria coincide with the literature values.Further，it is found that the phase behavior of the aqueous two-phase system can be correlated by the Flory-Huggins@equation。The reagents used are dextran from Pharmacia Co.Ltd.(Lot No.03375，Mn=24200，T40)and polyethylene glycol supplied by Wako Chemicals，Ltd.(Lot No.AWM2336，Mn=3000，PEG4000)。Distilled water from Wako Chemicals，Ltd.was used as pure water.The partition coefficients of-amylase supplied by Wako Chemicals，Ltd.(Bacillus Subtiles，Lot No.PDGO524)to the above aqueous two-phase system were measured。From the present data，it is found that-amylase is distributed mainly to the bottom phase(Dextran Rich Phase)。This partition coefficients were correlated by the Flory-Higgins@equation。The interaction parameters are found to depend on the molecular weight.

According to the development of biotechnology, sufficient separation techniques for bioproducts are strongly required. Among several separation techniques, a purification method due to the partition of bioproducts to aqueous two-phase system seems to be one of promising methods because the aqueous system provides a mild condition. To design the optimum solvent condition, the knowledge of phase behavior of the aqueous two-phase system and the partition coefficient of bioproducts is essentially needed.In the present study, the liquid-liquid equilibria of the dextran-polyethylene glycol- water system were measured at 20゜C. The present liquid-liquid equilibria coincide with the literature values. Further, it is found that the phase behavior of the aqueous two-phase system can be correlated by the Flory-Huggins equation. The reagents used are dextran from Pharmacia Co.Ltd.(Lot No.03375, Mn=24200, T40) and polyethylene glycol supplied by Wako Chemicals, Ltd.(Lot No.AWM2336, Mn=3000, PEG4000). Distilled water from Wako Chemicals, Ltd. was used as pure water.The partition coefficients of -amylase supplied by Wako Chemicals, Ltd.(Bacillus Subtiles, Lot No.PDGO524) to the above aqueous two-phase system were measured. From the present data, it is found that -amylase is distributed mainly to the bottom phase (dextran rich phase). This partition coefficients were correlated by the Flory-Higgins equation. The interaction parameters are found to depend on the molecular weight.