Tag: <span>stirred-tank bioreactor</span>

Stirred tank single-use bioreactors (SUBs) have been widely adopted for production of biopharmaceuticals such as monoclonal antibodies in mammalian cell culture. However, they are seldom used for commercial production of biologics with microbial fermentation. SUBs offer time-saving advantages because they do not require significant downtime for cleaning and sterilization, so finding a SUB that can perform well with high cell density microbial fermentation processes has the potential to increase the number of production runs. Therefore, for this study, a His-tagged protease inhibitor was chosen as a model protein to demonstrate that the Sartorius Biostat STR® MO, a SUB recently developed for microbial fermentation, is suited for recombinant protein production by high cell density Escherichia coli fermentation processes.

At 50 L scale, the SUB achieved good process control and allowed an oxygen uptake rate (OUR) of up to 240 mmoles/L/h. The fermentation runs produced up to 5.8 g/L of the soluble recombinant protein and a dry cell weight of >60 g/L at the end of fermentation. Additionally, the SUB showed a similar fermentation profile when compared with data from parallel runs in 15 L sterilise-in-place (SIP) vessels using identical media and process parameters. This study indicates that with a minimum investment of capital resources, stirred tank SUBs could be used in pilot-scale manufacturing with high cell density microbial fermentations to potentially shorten the timelines and costs of advancing therapeutic proteins to clinic.

Manufacturing

Because the Lambda MINIFOR bioreactor provides good mixing of cell culture, nutrients, and gases without any damaging hydrodynamic forces by using a bio-mimicking “fish-tail“ disc stirrer, it can be successfully applied for the cultivation of bacteria and yeast, insect, plant, and mammalian cells. However, reports on its application in mouse hybridoma cell culture using protein-free media is non-existent in the scientific literature. Therefore, this study describes preliminary findings of the Lambda MINIFOR bioreactor suitability in mouse hybridoma cell culture and antibody production using the SP2/O-Ag14-CB.Hep-1 mouse hybridoma cell and the PFHM-II protein-free medium as models. Results verified 2.45 × 106 viable cells/mL as the highest cell concentration, 86% as maximum cell viability, 0.0156/h as the exponential growth rate, 44 h as cell population doubling time, a stable phenotype measured by limiting dilution after 2.5 months, no antibiotic and antifoam requirements, 71.4% of IgG SDS-PAGE purity in the cell culture harvested supernatant, 38.68 ± 22.29 µg/mL, 39.23 ± 10.66 pg/cell/day, up to 99.5% of purity (sample measured by SDS-PAGE and SE-HPLC) after an IgG capture step based on protein A-Sepharose, a low pH incubation, and size-exclusion chromatography, no molecule aggregation, specificity for the CKTCTT epitope (located in the HBsAg “a” determinant), an IgG affinity constant equal to 1.11 × 1010 M-1, and < 78 pg mouse DNA/mg of IgG. In conclusion, this study corroborated a cumulative CB.Hep-1 mAb production of 1.77 g/15 days and validated the usefulness of the Lambda MINIFOR bioreactor in mouse hybridoma cell culture in protein-free media for research applications...

Biologics Production

Heterologous expression of membrane proteins remains a bottleneck for structural characterization by x-ray crystallography. Such proteins represent approximately 30% of the proteome and are not sufficiently represented in the Protein Data Bank (PDB). G-protein-coupled receptors (GPCRs) are an area of particular interest as it is estimated that one third of current FDA approved drugs act through this class of receptors. We have been studying rhodopsin with an interest in determining the conformational change that leads to signal transduction in this class of receptors. Although there has been some success in expressing select members of the large GPCR family in bacterial systems, the best characterized expression systems have generally been in mammalian tissue culture…

Biologics Production