“Salt tolerant” anion exchange chromatography for direct capture of an acidic protein from CHO cell culture

• HyperCel STAR AX is a salt tolerant sorbent.
• HyperCel STAR AX efficiently purifies active enzyme from neat feedstock.
• Higher capacity of HyperCel STAR AX compared to standard AEX with neat feedstock.
• Same optimization of operating conditions for HyperCel STAR AX as for standard AEX.
• Flexibility of HyperCel STAR AX: stable productivity independent of feed dilution.

The present study describes the use of the new HyperCel STAR AX “salt tolerant” anion exchange sorbent for the capture from Chinese Hamster Ovary (CHO) cell culture supernatant (CCS) of an acidic model protein (α-amylase). HyperCel STAR AX sorbent and other conventional anion exchangers were evaluated to purify biologically-active enzyme. Salt tolerance of the sorbent allowed reaching 5-fold higher dynamic binding capacity than conventional anion exchange during capture of the enzyme from neat (undiluted) CCS. After optimization of operating conditions, HyperCel STAR AX turned out to be the only sorbent allowing efficient protein capture directly from both neat and diluted CCS with consistent and satisfying purity, yield and productivity. Therefore implementation of the salt tolerant sorbent in industrial purification processes should allow avoiding time and cost consuming steps such as dilution or UF/DF that exclusively aim at establishing suitable conditions for ion exchange step without bringing any added value to the purification process performance. Altogether this study highlights the flexibility and cost-reduction potential brought in process design by the HyperCel STAR AX salt tolerant sorbent.