EXTRACTION OF PAPAIN BY AN IONIC LIQUID-BASED AQUEOUS TWO-PHASE SYSTEM

In this paper, N-butylpyridinium chloride ([BPy]Cl) + K2HPO4 aqueous two-phase systems (ATPSs) had been developed for the effective extraction of papain (PAP). Single factor experiments proved that the extraction efficiency of PAP was influenced by the temperature, pH, ionic liquid (IL) mass and the salt content. And 95.77% of PAP could be extracted into IL-rich phase under the optimum conditions. UV-vis, FT-IR and fluorescence spectrometer were used to confirm that there were no chemical interactions between PAP and [BPy]Cl, and the conformation of protein was not changed after extraction. The experimental results indicated that electrostatic interaction, salting out effect and intermolecular hydrogen bonding played important roles in the transfer process. All of the results indicated that [BPy]Cl-based ATPSs would have great potential application in bio-analysis and bio-separation.