Suspended bed chromatography, a new approach in downstream processing

A new technique in downstream processing, suspended bed chromatography has been developed. This hybrid technique exploiting the benefits of batch adso rption and the process advantages of an enclosed column system can be carri ed out using established contactors and adsorbents. A 44 cm I.D. IsoPak col umn and the anion-exchange cellulose Express-Ion Exchanger Q were used in t he purification of ovalbumin from hen-egg white. After suspension of 16.25 kg Express-Ion Q in 500 1 of feedstock containing 5 g protein/1, adsorption was effected by recirculation of the suspension using the IsoPak slurry pr eparation station. protein-loaded adsorbent was collected in the IsoPak col umn unit, where it was washed and protein desorbed using gradient elution a t a flow-rate of 300 cm/h. The entire process was complete in under 3 h. Wi th the introduction of pump-packed column systems and the availability of m echanically strong adsorbents suitable for column separations, suspended be d chromatography offers a new approach to downstream processing and provide s a less challenging alternative to batch separations. (C) 2000 Elsevier Sc ience B.V. All rights reserved.