Fully automated control of fermentation processes on the basis of cell count is now possible in a production environment for the first time.
Biotechnology will continue to experience above-average growth in the coming years. The primary reasons for this are the increasing content of biotechnological active substances (red biotechnology) in drug products, and regenerative fuels such as bioethanol or biodiesel (white biotechnology), which have become commercially attractive in light of the high price of oil. Driven by the growing pressure for greater efficiency, process analytical technology is widely used in the production of standard chemicals, in petrochemistry and the polymers industry. In biotechnological applications, however, online process analysis is currently restricted to a limited number of measurement methods for standard parameters such as pH, conductivity, dO2 or turbidity. In the future, novel analytical measurement systems will be able to monitor additional parameters online, including cell count and protein concentrations. BaychroMAT® CellCount, the technology platform introduced by Bayer Technology Services, is one step towards this future.
Even today, the production of chemical and pharmaceutical products often includes manual sampling so that reaction progress can be investigated by means of laboratory analysis. Because it often takes several hours or even days before a complete analysis report is available, the laboratory values obtained cannot be used for controlling a process. What is needed in these times of increasing competition is material concentrations in near real-time so that utilisation of capacity and product quality can be economically optimised.
This was realised some time ago in classic chemistry and the polymer industry with the implementation of innovative process analytical technology (PAT). Using spectroscopic and chromatographic measuring techniques, concentrations can be monitored round the clock and used for the targeted control of processes. Maximising yields demands comprehensive knowledge of the process, i.e. one has to know which critical parameters influence the process and how changing a parameter affects the overall process. This includes not only knowledge of physical parameters such as temperature and pressure, but also the change over time of material compositions.
PAT currently plays rather a minor role in biotechnology. Although physical parameters of fermentation processes, including temperature, pH, optical density, CO2 and oxygen pressure, are measured inline, i.e. directly in the process, there is generally no online determination of individual material components or the precise, near-time determination of the cell count, which is essential for the control of fermentation. One reason is that previously only a few reliable inline sensors (e.g. for glucose or ethanol) were available for determining the material composition directly in the fermenter, thus material analysis required that samples are removed from the fermenter. Sampling was frequently performed only once per day to minimize the risk of fermenter contamination.
Another reason that many companies in the pharmaceutical industry have chosen not to embrace the optimisation potential of PAT is the costly and time-consuming revalidation of their approved, registered production processes. In late 2002, the FDA launched a PAT initiative to encourage a paradigm change in the pharmaceutical and biotechnology industries.
One objective is to understand the influence of critical process parameters on the quality of the drug product and thus better understand the process. The critical parameters of many bioprocesses have not yet been completely identified. Otherwise, a producer would be able to explain what influence individual components (sugar, salts, vitamins, serum) have on his process. Why are auxiliary components formed, and why do they occur in different concentrations in different runs? Or can someone explain why it is necessary, despite constant
process conditions, to interrupt fermentation in a continuous fermentation process to guarantee consistent product quality?
In the case of a fermentation process, the critical parameters, which also include material concentrations and the cell count, must be identified and continuously monitored if these questions are to be answered. Technical implementation requires the complete automation of sampling, sample transport and sample analysis. In the past, employees had to transport the sample from the fermenter to the analytical device, breaking the automation chain. The BaychroMAT® technology platform from Bayer Technology Services GmbH solves this problem. With the development of BaychroMAT® CellCount for fermentation processes, a prototype which was presented at the Interkama and ACHEMA trade fairs in spring 2006, a fully-automated, online analysis system for fermentation control is now available for the first time. In spring 2006 BaychroMAT® CellCount went public at Interkama fair in Hannover, Germany.
Reliable, sterile sampling and the extraction of minimal sample volumes were made possible by the development of a novel, fully automated valve with minimal dead space installed in a standard DN 25 nozzle. The transport of the cell-bearing medium has been optimised to minimize shearing and cell losses, even with sensitive cell lines. After each sample is taken, the sampling valve and transport line can be cleaned with sterile steam and flushing liquids such that the system meets all CIP requirements. The samples are conditioned in an integrated sample preparation module then automatically made available to one or more analytical devices. In addition to the cell counter (Cedex® from innovates AG) integrated into BaychroMAT® Cell- Count, biochromatography systems or enzymatic bioanalysers can also be operated online with BaychroMAT®.
The MOAB software controls every component of the BaychroMAT® CellCount and uses multiple sensor systems to monitor sampling and ensure reliable operation. The platform can be connected to all common process control systems (analog and digital) via ARTS, the integrated analyser result transfer software. Thanks to the combination of these two software packages in conjunction with innovative sampling and the proven functions of the BaychroMAT® platform, fully automated control of fermentation processes on the basis of the cell count is now possible in a production environment for the first time.