Journal
MICROBIAL CELL FACTORIES
Volume 10, Issue -, Pages -Publisher
BIOMED CENTRAL LTD
DOI: 10.1186/1475-2859-10-47
Keywords
-
Categories
Funding
- Boehringer Ingelheim RCV (Vienna, Austria)
- project Competence team Molecular Biology by the City of Vienna [MA27]
Ask authors/readers for more resources
Background: The budding yeast Pichia pastoris is widely used for protein production. To determine the best suitable strategy for strain improvement, especially for high secretion, quantitative data of intracellular fluxes of recombinant protein are very important. Especially the balance between intracellular protein formation, degradation and secretion defines the major bottleneck of the production system. Because these parameters are different for unlimited growth (shake flask) and carbon-limited growth (bioreactor) conditions, they should be determined under production like conditions. Thus labeling procedures must be compatible with minimal production media and the usage of bioreactors. The inorganic and non-radioactive S-34 labeled sodium sulfate meets both demands. Results: We used a novel labeling method with the stable sulfur isotope 34S, administered as sodium sulfate, which is performed during chemostat culivations. The intra-and extracellular sulfur 32 to 34 ratios of purified recombinant protein, the antibody fragment Fab3H6, are measured by HPLC-ICP-MS. The kinetic model described here is necessary to calculate the kinetic parameters from sulfur ratios of consecutive samples as well as for sensitivity analysis. From the total amount of protein produced intracellularly (143.1 mu g g(-1) h(-1) protein per yeast dry mass and time) about 58% are degraded within the cell, 35% are secreted to the exterior and 7% are inherited to the daughter cells. Conclusions: A novel 34S labeling procedure that enables in vivo quantification of intracellular fluxes of recombinant protein under production like conditions is described. Subsequent sensitivity analysis of the fluxes by using MATLAB, indicate the most promising approaches for strain improvement towards increased secretion.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available