Multimodal chromatography has increasingly been utilized in several bioprocess based platforms due to its distinctive selectivity. Previously, our lab had reported a series of multimodal anion exchangers (MMAEX) with varying aromatic ring substitutions and its effect on protein selectivity. The nature of hydrophobicity and the ligand geometry of the bulky groups were found to play a major role in driving protein’s selectivity on the adsorbents. Probing further, we wanted to understand the recovery issues that are generally observed to be a concern when dealing with the MMAEX ligands in the industries. In regard to these, two other MMAEX ligands containing guanidine groups were evaluated. The chromatographic experiments consisted of a series of linear salt gradients that were carried out with a set of model protein library which has demonstrated to have recovery issues. The role of ligand density and ligand structure was evaluated for binding of proteins to the adsorbents and the study was compared with the parent ligand structure, Prototype 13 and a commercial adsorbent, Capto Adhere. Interesting results were observed with these MMAEX adsorbents as it was seen that while a single guanidine moiety exerted a hydrophobic type of interaction leading to recovery issues, the other structure with two guanidine moieties did not pose these problems. It was also demonstrated that a linear pH gradient could alleviate the recovery problems so observed. These results indicated that the recovery issues can be circumvented by careful modification of the ligand structure and/or meticulous use of experimental conditions to employ the multi-mode interaction of a multimodal chromatography for improvement in selectivity.

Evaluation of multimodal anion exchangers for protein recovery

ACS Fall 2020 Virtual Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.