Liquid/liquid Extraction of Proteins Using an Ionic Liquid

• Main Authors: Jin-chu Chen, 陳俊竹
• Other Authors: Tiing Yu
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/92985918319474201969

碩士 === 國立交通大學 === 應用化學系所 === 93 === Due to their unique physicochemical properties, such as high polar, high conductivity, no detectable vapor and relatively high thermal stability, ionic liquids(ILs) continue to attract wide research interests on the capability for replacing traditional volatile organic compounds (VOCs), including in the applications of liquid/liquid extraction, organic synthesis and inorganic catalysis. In addition, ILs are relatively safer than VOCs and recyclable, so they are regarded as green solvents. Protein purification is an important task in biochemistry and biotechnology. Traditionally, two liquid/liquid extraction techniques, i.e. two-phase aqueous polymer and reverse micelle systems, have been used for protein purification and enrichment. In this study, we explore that protein can be transported between aqueous solutions and a mixture of ethyl acetate and ionic liquid [C4mim][PF6] by manipulation of pH. Proteins can be extracted from one aqueous solution at low pH into IL phases and back-extracted to another aqueous solution at high pH. For example, the forward extraction of cytochrome c molecules reaches to an almost quantitative completion at pH 2.7 and back-extracted to an aqueous solution at pH 11. Myoglobin can be completely extracted at pH 5, but the recovery is only about 50 % at pH 13. As for ribonuclease A, the forward extraction reaches ~60 % at pH 2 while the recovery reaches to quantitative completion at pH 11. Both the forward and backward processes are found reaching equilibrium in very short time. Therefore, this technique may be applied in purification and enrichment of proteins and thus extends a new field for the application of ILs.