March 15, 2013 (Vol. 33, No. 6)
An essential component in the development and control of bioprocesses for industrial production of recombinant proteins is the delivery of fast, accurate, and reliable process data. The precise monitoring of substrates (nutrients) and metabolites in animal and bacterial cell culture is critical to avoid underfeeding or buildup of toxic metabolic end-products during fermentation. Uncontrolled metabolites can negatively affect cell growth and viability, as well as protein quality and yield. Therefore, an exact tracking of fermentations ensures reproducibility and is the key to both optimizing process development and validation.
Typical parameters tested are glucose, lactate, glutamate, glutamine, ammonia, sodium, and potassium. Currently, multi-analyzer systems measuring substrates and metabolites use membrane-based enzyme-dependent biosensors and ion-selective potentiometry. Major disadvantages of these instruments are the changing quality of enzyme membranes over time, high material costs, measurement nonlinearity, and overall low sensitivity and accuracy.
Testing the Roche Cedex Bio Systems
The Cedex Bio Analyzer and recently launched Cedex Bio HT Analyzer were developed to improve in-process monitoring during fermentation. The Cedex Bio HT Analyzer, designed for high-throughput applications in process development, performs up to 320 tests per hour. Cedex Bio HT Analyzer results are perfectly consistent with results produced by Cedex Bio Analyzer. The technology using proven Roche instrumentation platforms excels with increased sensitivity and reproducibility in expanded measurement ranges, compared to currently used instruments (Table).
An automated dilution capability extends the measurement ranges and significantly reduces operator-caused variability. No manual dilution is required before applying samples to Cedex Bio Analyzers. A variety of photometric assays (e.g., LDH [lactate dehydrogenase], IgG [immunoglobulin]) and ion selective electrodes (e.g., sodium, potassium) are combined in one instrument and allow flexible test ordering for individual samples.
Superior Cedex Bio Analyzer Data Quality
An established analyzer using membrane-based technology was compared to the Cedex Bio Analyzer using reference standards (see glucose, lactate, and glutamine in Figure 1). Day to day, side by side comparisons showed the superior accuracy and linearity of the Cedex Bio Analyzer.
In addition, the Cedex Bio Analyzer’s increased sensitivity made nutrient limited fermentations possible. Also, small changes in the metabolite profiles of the fermentation process could be detected.
Findings Using Correlative Studies in the Field
The membrane analyzer required laborious maintenance, calibration, and constant recovery control. Besides the higher data quality of the Cedex Bio Analyzer correlative studies (see glucose and lactate in Figure 2) from batch-fed mammalian cell fermentation, it shows that the Cedex Bio Analyzer can easily replace a membrane analyzer without any offset.
The Cedex Bio Instrument’s ability to analyze product quality parameters, such as LDH (representing the amount of released [i.e., cytosolic proteases]) and IgG (titer) from the same sample, represents an additional advantage.
The Cedex Bio Analyzer combines three devices in one platform, allowing multiple parameters to be tested from the same sample in minutes. Automated dilution reduces operator dependent steps and variability. Easy-to-use robust photometric, ion selective, and turbidity assays are reliable, reproducible, and directly comparable between instruments in different locations. The resulting sensitive, precise, and accurate analytical data guarantee high level control of the fermentation process.
Dr. Claudia Schmitt
+49 8856 60 10210
CEDEX is a trademark of Roche
For use in quality control/manufacturing processes only.