Application of Membrane Chromatography in Bioprocessing

Abstract

<p> Improved and efficient bioprocessing technology is a key requirement in the manufacture of biopharmaceuticals. The increasing need to reduce biopharmaceutical cost is driven by the business challenges such as the emerging biogenerics. The great advances in upstream technologies make bioseparation the major cost in bioprocessing. Developing efficient bioseparation technologies is therefore strongly desired. Membrane chromatography is a promising bioseparation technology which combines the advantages of membrane technology and chromatography, thus making high-throughput and high-resolution bioprocesses feasible. This thesis focuses on the novel applications and improvements of membrane chromatography: bioprocessing of transgenic tobacco derived monoclonal antibodies and PEGylated proteins, integrated bioprocessing for antibody fragmentation, study of antibody binding on membranes and the development of novel membranes.</p> <p> Membrane chromatography based bioprocesses were developed for purification of monoclonal antibody (mAb) from transgenic tobacco, primarily addressing the challenge of low mAb abundance in the feed material. PEGylated proteins were purified, demonstrating that high-throughput and high-resolution purification of low-binding-propensity proteins was feasible using membrane chromatography.</p> <p> Membrane chromatography based reactant adsorptive membrane bioreactor separator (RAMBS) systems were developed to integrate enzymatic fragmentation of human IgG with the purification of target fragment. This novel system facilitated the process intensification and led to higher IgG digestion than in liquid phase reaction.</p> <p> The mechanism of hydrophobic interaction based IgG binding on synthetic membranes was studied using the RAMBS system. The results showed that the binding took place primarily through a combination of the hinge and CH2 domain of Fc. This study provides a new approach for studying antibody interaction with membranes and surfaces and could help design membrane-based antibody purification, immunoassay and biomaterials.</p> <p> PEG grafted filter paper was developed as an inexpensive alternative to commercial synthetic membranes. These novel membranes possessed high permeability and low fouling tendency and demonstrated good selectivity and reusability in monoclonal antibody purification.</p>