Process development in affinity separation of glycoconjugates with lectins as ligands.

Process development for affinity separation is a crucial prerequisite for a successful biospecific isolation of biological active substances like glycoconjugates or enzymes. The functionalization of polymer and silica based adsorbents and their influence on the adsorption behaviour of the modified adsorbents are presented. Improvement of the immobilization conditions for different lectins lead to a stable binding of more than 90% within 4 h of ligands applied to the immobilization solution. The prepared adsorbents are characterized according to specificity, stability and capacity. The isolation of the glycoprotein fetuin from fetal calf serum with wheat germ agglutinin adsorbents and the purification of horseradish peroxidase with concanavalin A (Con A) adsorbent are described. The Langmuir model, using glucose oxidase as glycoprotein and Con A adsorbents, expresses the sorption behaviour. The fixed bed separation is represented by the dispersion model. The process simulation supports the process development evaluating design parameters and investigating and optimizing process conditions. The influence of the flow as well as the concentration of contaminants competing with the valuable product for the ligands on the separation performance are demonstrated and discussed.