Vikas Yelemane Sunanda Rajanna

• Integration and intensification in bioprocessing has a significant role in the development of cost-effective recovery and purification schemes. Expanded Bed Adsorption (EBA) is an integrated unit operation, which allows for simultaneous clarification, concentration, and partial purification -directly from a non-clarified feedstock. EBA technology, however, suffer from unwanted interactions between biomass components and the fluidized adsorbent. This phenomenon compromises dynamic binding capacity and overall process performance. The main objective of this Thesis work was the optimization of EBA processing using surface-modified adsorbent beads. A detailed study on cell adhesion behavior of four different industrially relevant types of biomass on twenty-six different commonly occurring surfaces was conducted. This study resulted in deriving a “stickiness” factor for every type of biomass. In the next stage, a microplate method was developed for high throughput screening of cell-repellent-polymers. Experimental results, in combination with xDLVO-based interaction energy calculations allowed for the selection of three cell-repellent adsorbent systems. Process performance was validated using commercial affinity adsorbents for the purification of monoclonal antibodies (MAB) from Chinese Hamster Ovary (CHO) crude feedstock. Finally, MAB purification was performed employing PAA-coated and PMA-coated adsorbents at pilot scale. PMA can be proposed as an excellent cell-repellant polymer for application in EBA. We extended our research into two more aspects: i) the modeling of the CHO cells transportation in EBA and ii) a detailed study on the effect of DNA binding on EBA adsorbents. These studies provided additional insights into the deterioration of the binding capacity of the adsorbent. This work has added significant value for the advances of expanded bed adsorption. Polymer shielded adsorbents were successfully used for mAb purification, using high cell density CHO cell broth. Polymer shielding of the adsorbents was found to be effective in reducing biomass adhesion and also yielded higher dynamic binding capacities in the presence of cells.