(244a) High Performance Protein Separation by Ion Exchange Membrane Partitioned Free Flow Isoelectric Focusing System

The objective of this study is to investigate a combination of Ion Exchange Membranes and Free-Flow Isoelectric Focusing (FFIEF) technology for high-selectivity and high-flux protein separation, in which ion exchange membranes are used as the separation media. A FFIEF device has been successfully designed and extensive experiments have been conducted to prove its effectiveness in enhancing the protein separation performance. Three types of membranes were employed in this work and they were commercial microfiltration (MF) ion exchange membranes, commercial neutral UF cellulose membranes, and home-made ultrafiltration sulfonated polysulfone (UF SPSf) ion exchange membranes. The protein separation results show that home-made UF SPSf membranes have the superior selectivity and flux to other membranes. This is due to the fact that the pH gradient between two sides of membranes as well as the interaction between the protein molecules and membrane surface plays an important role in the high-performance protein separation. This phenomenon is very similar to the native mass transfer system in human body. By applying a semi-batch separation process and optimizing various experimental conditions, a high-purity (> 90%) and concentrated target protein is obtained at the permeation side of home-made UF SPSf membranes with a high flux. More over, it is possible to separate multi-components mixture into high purity fractions continuously through one multi-chambers IEM-FFIEF process.