An Analysis of Protein Adsorption and Desorption from Anion Exchange Resins With Applications to Countercurrent Tangential Chromatography

Open Access
Author:
Barth, Morgan Reilly
Area of Honors:
Chemical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Andrew Zydney, Thesis Supervisor
  • Themis Matsoukas, Honors Advisor
Keywords:
  • Chromatography
  • anion exchange
  • equilibrium
  • kinetics
Abstract:
Column chromatography is used extensively for the purification of high value biological products, exploiting differences in binding affinity to achieve high resolution separations. There are significant challenges in using packed bed chromatography columns for very large scale processes including: poor flow distribution, excessive pressure drops, column packing issues, slow operation, and high cost. Countercurrent tangential chromatography has recently been proposed as an alternative separation process, with the chromatography resin pumped in the form of a slurry through multiple hollow fiber membrane modules using a countercurrent configuration. The objective of this thesis was to obtain quantitative data for the rates of protein adsorption and desorption and binding equilibria on different anion exchange resins which are needed to design successful countercurrent chromatography systems. Experiments were performed using two commercially available anion exchange resins, Macroprep 25Q and Q Sepharose, with bovine serum albumin (BSA) and myoglobin as model proteins. Data were obtained for protein adsorption and desorption as a function of time over a range of protein concentrations and resin volume fractions. The equilibrium binding data were in good agreement with a classical Langmuir isotherm with a maximum capacity for BSA of approximately 13 g/L for the Macroprep 25Q and 35 g/L for the Q Sepharose resin. The rate of adsorption was described using a simple mass transfer model with a lumped mass transfer coefficient. Uptake kinetics were much faster with Macroprep 25Q than Q Sepharose due to its smaller particle size. These results provide important information that can be used for the design of effective countercurrent tangential chromatography systems.