Bioprocessing
Problem: Optimizing the Production of a Protein Therapeutic
Recombinant expression of a protein therapeutic involves selecting the best cell line and optimizing the growth conditions for the highest quality and yield. Optimizing protein expression requires manipulation of variables such as media composition, temperature, and oxygen. As these are changed, several parameters, such as pH, cell density, and product yield, are monitored to study the effect. Given the large numbers of variables involved, especially in the composition of media nutrients, it is often more difficult to determine globally optimal conditions. Even more difficult is trying to understand the variations batch-to-batch.
Solution: Global Analysis of Biochemicals
Instead of monitoring a handful of biochemcals, Metabolon's comprehensive biochemical profiling service analyzes hundreds of biochemicals, both metabolites in the cells and components in the media. By performing these analyses in different reactors and over time, many relevant changes can be monitored. For example, media nutrients which are rate limiting can be identified. In addition, biochemicals related to cell toxicity can be seen. The result is a comprehensive analysis for optimizing expression, leading to:
- increased product yield and quality
- decreased substrate consumption
- better control of metabolic activity
- lower process costs
- increased process reliability and reproducibility
- maximized operational efficiency
Case Study: Bioreactor Monitoring
Objective
Demonstrate the global biochemical changes in bioreactors.
Methods
1. Eight bioreactors (CHO cells), testing two inoculants and two media batches in multi-factoral design
were sampled over seven time points (12 days).
2. Each sample was spun down to separate the media from the cells.
3. Media and cells were analyzed separately on Metabolon's platform.
Results
The table below shows the number of biochemicals measured from each type of sample, as well as the biochemicals which were unique or common to cells and media:
| |
Biochemicals Measured |
| |
Cells |
Media |
Total |
388 |
271 |
In both cells and media |
198 |
Cells only |
190 |
|
Media only |
|
73 |
The following 3-D plot shows biochemical changes for a single reactor over time (time course runs back
to front). Each dot represents a different biochemical (plotted along the vertical axis), each color
represents a different time point, and the extent of displacement from one along the horizontal axis
represents the fold-change in that biochemical relative to the first time point (Day 2):
Individual biochemicals can be examined to show changes over time. Six biochemicals which existed in
both cells and media are shown in the figure below (red = cells, blue = media):
By looking at a number of media reagents, the rate limiting reagent can be easily determined, as shown in the graph below:
|
