Sunday, November 8, 2009 - 3:30 PM
S5
High Throughput Screening and Selection of Pichia Pastoris cell lines using Microreactor Miniature Bioreactor System
Seemab Shaikh, GlycoFi/Merck, n.a, Lebanon, NH
Recombinant therapeutic glycoproteins have gained importance recently and represent an ever growing class of biopharmaceuticals. This increased demand for therapeutic glycoproteins has entailed the development of alternative expression systems. With the advent of glyco-engineered strains capable of producing therapeutic glycoproteins with human glycoforms, Pichia Pastoris is emerging as a robust and economical expression platform compared to the traditionally used mammalian cell cultures. However, as is the case with any expression system, there can exist variability in terms of product quality and yield depending on the protein being expressed, the host and the process used for production. Furthermore, it is imperative that strain development efforts have a line of sight to the scale-up process. Here, we demonstrate a novel high-throughput screening (HTS) system using a 5 mL-scale miniature bioreactor (Microreactor) to perform clonal selection for the purpose of identifying strains with the proper robustness and the production of protein with the requisite quality attributes (e.g. N-glycosylation profile). Furthermore, we demonstrate a screening protocol that reduces well to well variability in terms of productivity and product quality attributes with a > 90% success rate. Finally, using protein titer and N-linked glycosylation profiles we compared clone ranking at the MicroReactor scale to a ranking performed at a larger scale and found that the rankings were similar. In conclusion, we have developed an efficient, small scale process for the evaluation and selection of clones for further evaluation and scale up.