CBEE Dept. Seminar: Karthik Boppidi and Yang Liu

CBEE Dept. Seminar: Karthik Boppidi, PhD Student and Yang Liu, PhD Student

UMBC CBEE

Please join the Chemical, Biochemical and Environmental Engineering Department, for a seminar given by PhD students Karthik Boppidi (Marten lab) and Yang Liu (Frey lab).

Presentation Title:

Author: Karthik Boppidi

Abstract:

Filamentous fungi are widely used in the production of a variety of biomolecules as they have the unique ability to secrete tremendous amounts of native protein. However, results are often not as good for recombinant protein. But it is unclear as to why this occurs, because the fungal protein secretory pathway is a poorly understood.  Previous results implied a particular Aspergillus nidulans, temperature sensitive (Ts), mutant strain (podB), might have the ability to secrete higher amounts of protein. Thus we investigated the role of the podB mutation on growth and protein secretion. We found that the podB mutation resulted in lack of growth of biomass in liquid fermentations. But, we observed a significant increase in protein productivity due to the mutation. Upon further analysis of the secretome by quantitative mass spectrometric analysis we found a large number of intracellular proteins in the secretome of A. nidulans. Furthermore, the unfolded protein response (UPR) was up regulated in the mutant. Taken together, the data suggests that podB is a critical component of the protein secretory pathway.

Presentation Title:

Purification of therapeutic antibody products with neutral to acidic pI values using non-affinity capture methods

Abstract:

Process-scale methods for the purification of monoclonal antibodies typically employ protein A affinity chromatography as an initial capture step followed by one or more polishing steps to achieve therapeutic grade purity. This work investigates the use of both chromatofocusing and ion-exchange chromatography at constant pH with salt gradient elution as alternatives to protein A chromatography for the initial capture step in an overall purification process for several antibody fusion proteins with pI values in the acidic to neutral range. The specific conditions employed for the capture step for the case of chromatofocusing, such as the identities and concentrations of the buffering species used, were selected with the aid of computer simulations and a process development tool which incorporated a 3D analytical separation method. Alternative operating conditions were compared experimentally with regard to the product yield and column loading achieved as well as the product purity obtained in terms of host cell protein (HCP) and aggregate clearance.  Results of this study indicate that chromatofocusing and ion-exchange chromatography with salt gradient elution are useful alternatives to a protein A chromatography capture step in many practical cases. This is especially true for the case of chromatofocusing when it is possible to exploit the ability of the method to employ pH gradients to affect the protein adsorption behavior, to create complex gradient shapes that are self-forming inside the column, and to simultaneous focus and separate proteins inside the column.