Non-invasive approach is said to be ideal for cultivation processes as the measurement is made inside the actual process without interfering with the living cells
Monitoring the product concentration during a running process is one of the key factors for an optimised process control.
Alpharma is one of the leading companies in the world using fermentation of microorganisms for the production of different antibiotic substances.
Until recently, off-line HPLC measurements had used to monitor the concentration of these antibiotics.
Sample preparation is necessary before performing these HPLC measurements including time-consuming steps such as sampling, filtration and adjustment of pH.
The time spent for the analysis of one sample of a specific peptide-antibiotic can be at least 30 minutes, requiring an HPLC system set up and running parallel to the process, as well as a technician performing these measurements.
This means that to obtain these results one person is constantly required, but even with this effort results can at best only reflect the progress of the fermentation with half an hour delay, and can therefore not be compared to real process monitoring and process control.
To limit the manpower and time required, samples are collected during fermentation and analysed after the fermentation providing information useful only for documentation purposes.
The BioView system was tested to achieve real on-line information about the production of the peptide-antibiotic.
The 2D-fluorescence spectra measured on-line during fermentations in a pilot scale show strong fluorescence peaks.
Using chemometric methods a correlation between the fluorescence information and the corresponding product concentration was found.
The comparison of the predicted peptide-antibiotic concentration using a chemometric model with the measured concentration shows a good correlation throughout the whole measurement range.
During validation the calculated concentrations were compared to the HPLC measurements with extremely satisfying results.
Today HPLC measurements can be substituted by having a BioView running unattended 24 hours a day and delivering data on-line.
In addition to the possibility of on-line prediction of the product concentration, valuable information about the optimum harvest time can also be derived from the fluorescence spectra.
These results enable the process operator to stop the fermentation process when the product concentration in the medium is at its highest level.
Stopping the fermentation too early or leaving it to run for too long only to increase costs is thus avoided, and overall far greater efficiency of the process is achieved.
Prediction of the product concentration and determination of the optimal harvest time saves both time and money.
Based on the results from the pilot plant, Alpharma is now working on the integration of the BioView system in its production facility.
