Pichia pastoris secretes recombinant proteins less efficiently than Chinese hamster ovary cells but allows higher space-time yields for less complex proteins.
Bottom Line: In contrast, the STY of the HSA producer was 9.2-fold higher compared to CHO cells because of the shorter process time and higher biomass density.The results indicate that the protein secretion machinery of P. pastoris is much less efficient and the secretion rate strongly depends on the complexity of the recombinant protein.However, process efficiency of the yeast system allows higher STYs for less complex proteins.
Affiliation: Austrian Centre of Industrial Biotechnology (ACIB GmbH), Vienna, Austria; Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria.Show MeSH
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Mentions: One means to optimize feed rates is to adapt the feed profile to the optimal trajectory of STY. We have shown before  that specific secretion rate and specific growth rate correlate strictly in P. pastoris which is also observed here. In CHO cells this correlation is rather weak ( Fig. 3). Therefore different optimization strategies need to be applied to the two production platforms. In P. pastoris, optimization leads to initial high feed rates for rapid accumulation of biomass, followed by a phase of decreasing μ, thus allowing time for product accumulation . In CHO cells, the fed batch strategy rather aims at maintaining reasonably high viable cell concentrations. This difference in feed strategy leads to large differences in process duration spanning from 50 to 150 h for P. pastoris up to 21 days for CHO cells . The STY is a measure for the product output per bioreactor volume and time, and thus illustrates the respective capital costs per unit of product. STY is reverse proportional to process duration, so that in other words the capital costs per unit product increase proportionally with the time needed to achieve a defined amount of product. Especially for the biopharmaceutical industry capital costs for production plants are a major factor of total production costs , so that maximizing STY is a valid optimization strategy.
Affiliation: Austrian Centre of Industrial Biotechnology (ACIB GmbH), Vienna, Austria; Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria.