On-Line Recovery of Large Molecules using Reciprocating Size Exclusion Chromatography with Application to Enzymatic Conversion System

초록

The reciprocating size exclusion chromatography(RSEC) was developed to separate larger molecules from the mixture solution in process. In RSEC, the larger solutes are separated from the feed mixture in frontal mode in a gel packed column, and the remaining smaller solutes as a mixture in the column are returned by reverse flow to the feed reservoir(1). Blue Dextran, a standard large molecule, was successfully recovered on-line from the aqueous mixture solution by RSEC using Bio-Gel P, while nickel nitrate, a standard small molecule, was diluted as a mixture solution in the feed tank. RSEC was also operated with temperature swing in a synchronous mode with flow direction to concentrate the small solutes in addition to the on-line recovery of the large solutes. The concentration of small solutes in RSEC with temperature swing was made possible by taking advantage of the temperature-dependent swelling properties of the porous gel(2). On-line recovery of large molecules and simultaneous concentration of small molecules in mixture solution is an unusual trial, comparing to the routine practice of filtration where small molecules are isolated from mixture. The performance of RSEC was compared with the conventional size exclusion chromatography (SEC) with repeated feed. In SEC, the larger solutes in each feed pulse were separated from the smaller ones in elution mode and recovered from the column, while the separated small solutes were recovered and recycled to the feed reservoir. The time interval between each feed pulses was arranged to have the elution band of large solutes which were isolated from a feed pulse exit the column just after the band of small solutes from the preceding pulse. The recoveries of the large solutes were comparable between the RSEC without temperature swing and the SEC with repeated feed. SEC with repeated feed was not expected to concentrate the small solutes in the feed reservoir, letting aside the thermodynamic inefficiency, incurrin