Direct coupling of expanded bed adsorption with a downstream purification step.

In the course of developing a cost-effective, scaleable process for the purification of a recombinant protein from Chinese hamster ovary (CHO) suspension cell culture, we investigated direct capture of this molecule using expanded bed adsorption (EBA). EBA combines clarification, purification, and concentration of the product into a single step. The unclarified bioreactor material was directly applied to a STREAMLINE 25 column containing an affinity STREAMLINE adsorbent. This work focused on simplifying the EBA operations and minimizing the overall processing time by running the EBA column unidirectionally, eluting in the expanded bed mode, and coupling the EBA column directly with ion exchange or hydrophobic interaction chromatography. Unidirectional EBA was clearly a simpler unit operation and did not require the use of specialized equipment. The increase in the elution pool volume was insignificant, especially when the EBA column was eluted directly onto the downstream column. Scale-down was simple and could be automated. Coupling of unidirectional EBA with a downstream purification step reduced processing time, equipment requirements and cost.