Sequential membrane-based purification of proteins, applying the concept of multidimensional liquid chromatography (MDLC).

A purification method for formate dehydrogenase from Candida boidinii has been designed by using a sequence of membrane-based adsorbents. The membranes carrying ion-exchange and dye ligands (Sartobind) are general-purpose adsorbents for proteins. The membranes were used in an on/off mode. A sequence of cation exchange, dye-ligand and anion exchange allows to purify the enzyme as judged by SDS-PAGE and assay of specific activity. The sequence of ligands and the buffer conditions were chosen in such a way that the fraction eluted from one membrane could be directly loaded on the next membrane. Thereby an integrated version of MDLC was realized with membrane-based adsorbents. The excellent scaleability from micro- to laboratory scale (factor 40) indicates that the method could afford a general approach to develop purification trains since the micro-scale allows for a rapid screening of adsorbent types and sequences.