In recent years, the utilization of online process analytical technology (PAT) has become a high-profile endeavor in the biotechnology industry.
Since the early 1980s, a number of fermentation scientists have employed Thermo Scientific™ Process Mass Spectrometers to reliably monitor the composition of gas streams into and out of bioreactors and fermenters.
When making the first steps towards process control, it is not uncommon for some to think that the measurement of carbon dioxide and oxygen in the effluent is all that is needed and that sufficient accuracy can be acquired by discrete measurement technology. Both of these assumptions are incorrect.
Due to external biology (trees and people) that inevitably alter the input to the instrument air system, the sparge gas is always variable. The ubiquitous twin-tower desiccant dryer systems will also either regurgitate or absorb CO2 depending on their place in the regeneration cycle.
In order to supply accurate pre-screening for possible contamination, only an accurate comparison of effluent and sparge gas is sufficient. To calculate real-time information regarding culture respiration and the availability of nutrients, an accurate comparison is also needed.
For effective control, the minimum requirements are as follows:
- Measurement of sparge and effluent gases
- Local support
- Flexible analysis schedules and techniques
- All gas components must be measured
- Operational reliability and simplicity
- High accuracy is needed to calculate meaningful metrics
- Automatic calibration of all components
Figure 1. Typical benchtop bioreactor. Image Credit: Thermo Fisher Scientific – Environmental and Process Monitoring Instruments
Source: Thermo Fisher Scientific – Environmental and Process Monitoring Instruments
Magnetic Sector
Analytical Performance |
N2 |
N2 |
O2 |
O2 |
Ar |
Ar |
C2 |
C2 |
| %mol |
%mol |
%mol |
%mol |
%mol |
%mol |
ppm |
ppm |
| Mean |
St Dev |
Mean |
St Dev |
Mean |
St Dev |
Mean |
St Dev |
| Day 1 |
78.0807 |
0.0028 |
20.9459 |
0.0026 |
0.9337 |
0.0003 |
396.84 |
1.31 |
| Day 2 |
78.0767 |
0.0023 |
20.9494 |
0.0023 |
0.9342 |
0.0003 |
397.46 |
1.25 |
| Day 3 |
78.0761 |
0.0024 |
20.9500 |
0.0023 |
0.9342 |
0.0003 |
397.34 |
1.28 |
| Day 4 |
78.0798 |
0.0023 |
20.9469 |
0.0023 |
0.9337 |
0.0003 |
396.31 |
1.31 |
| Day 5 |
78.0777 |
0.0030 |
20.9487 |
0.0028 |
0.9339 |
0.0003 |
396.76 |
1.34 |
| Day 6 |
78.0741 |
0.0023 |
20.9518 |
0.0022 |
0.9344 |
0.0003 |
397.47 |
1.27 |
| Day 7 |
78.0750 |
0.0023 |
20.9512 |
0.0022 |
0.9342 |
0.0003 |
397.23 |
1.30 |
Taking the First Steps Towards Advanced Process Control
A fully instrumented fermentor is shown in the process diagram. In order to monitor a large variety of process variables in real-time, both liquid and gas-phase measurements are supplied.
These data are fed into the advanced process control (APC) system, which usually includes hybrid models made up of neural (nonlinear) network models and formal (linear) models.
The APC system supplies the set-points for many variables, which include control of nutrients, sparge content and flow, amino acids, in addition to the traditional variables of temperature, agitation, pressure, and pH.
This diagram represents the ideal situation for process understanding and scale-up, but there is an amount of complexity and cost associated with this comprehensive technique.
As it supplies significant added value with minimum risk and moderate cost, the more common technique is to add a multistream mass spectrometer. Without compromising sterility, the Thermo Scientific™ Prima PRO is equipped to monitor 60+ fermentors.
The Prima BT supplies a bench-top solution for smaller-scale fermentors that are configured with 15 samples and six calibration ports. The complete, highly precise gas composition measurements supplied by both models are incorporated easily into the APC system.
Huge enhancements in process control can be attained extremely quickly, normally within one or two days of a startup.
Figure 2. Fully instrumented fermentor. Image Credit: Thermo Fisher Scientific – Environmental and Process Monitoring Instruments
Supplying Value During Every Stage of Product Development
Advanced instrumentation is required for the complex manufacturing processes which are inherent in biotechnology in order to ensure an optimal path to the final product. The key to increasing profits is mitigating risk throughout the scale-up process.
The Prima PRO and Prima BT process mass spectrometers provide the precision and speed needed to track process dynamics reliably and enable timely corrective action to be taken.
The Prima platform technology helps bring products to market more quickly, enhance profits and increase yields, and for a rapid return on investment, from research and development to the final product creation.
Acknowledgments
Produced from materials originally authored by Thermo Fisher Scientific
This information has been sourced, reviewed and adapted from materials provided by Thermo Fisher Scientific – Environmental and Process Monitoring Instruments.
For more information on this source, please visit Thermo Fisher Scientific – Environmental and Process Monitoring Instruments.