With most processes that are unique to the pharmaceutical industry the manufactured products will sooner or later come into contact with people in the form of medicine, cream, infusions, etc. As a result, it is particularly important to ensure that the measuring and control technology used in these processes is protected. If we take a look at fermentation, for example, the advantages that additional protection offers are easy to see.
The author: Christina Hoffmann Market Segment Manager Pharmaceuticals and Food, Jumo
Fermentation is a core process in the production of biological agents in the so-called white biotechnology field. This sector is concerned with the manipulation of microorganisms or enzymes to produce fine chemicals, food additives, primary products for agriculture or pharmaceutics and excipients for the processing industry. The aims of this technology include conserving fossil fuels and replacing classical industrial production methods with sustainable ones. The challenge: biological agents are highly susceptible to temperature and shearing. As such, they are very sensitive to changes in pH, pressure and contamination. It is therefore particularly important to monitor temperature, pH, oxygen and pressure in white biotechnology processes.
Critical process parameters
The microorganisms or enzymes used in the production of biological agents are very sensitive to their ambient conditions. Their task is to metabolise or convert the fundamental culture medium or substrate into the designated end product. In doing so, all operating parameters of the fermenter must be kept within narrow limits. Even small deviations could result in the entire batch being unfit for circulation.
All microorganisms and enzymes have a specific optimum temperature at which they multiply best. Irreversible damage may result if the temperature rises above this optimum value. However, if it falls below this value, then the insufficient metabolic speed could cause the process to take longer. Temperature control is implemented through heating and cooling circuits. Most microorganisms and enzymes also have a narrow tolerance range for pH. The pH in the fermenter is consequently recorded using a suitable sensor. Its output signal is used to control pumps, which can reduce or increase the pH in the fermenter as necessary by adding acid or lye.
Another important parameter for metabolisation with microorganisms and enzymes is the specific need for oxygen. Oxygen dissolves poorly in water, which means that a sufficient supply of aerobic formulations is difficult. In a fermentation medium with a temperature of 37 °C, for example, the solubility of oxygen is around 3 to 5 mg/l. Increasing the atmospheric pressure in the fermenter has proved to be an effective method of increasing the concentration of dissolved oxygen in cultures that are sensitive to oxygen and shearing forces.
Recording and documentation
During fermentation it is essential that all measuring devices respond quickly to process control and that they function in a precise and reliable manner. The necessary monitoring and documentation of the process can, for example, be handled by a paperless recorder. The critical measured values during the process are graphically represented for individual batches. At the same time they are documented and archived in a tamper-proof way. Paperless recorders such as the Jumo Logoscreen fd must meet the particular requirements of FDA 21 CFR Part 11 for documenting pharmaceutical processes such as fermentation. Amongst other things, the Logoscreen fd has up to 42 measuring inputs, offers an integrated Web server as standard and provides diverse display modes, for example online visualisation on three freely programmable HTML pages, simultaneous recording of up to three batch reports and simultaneous display of up to four measuring signals (process parameters). The device software and the PC software components likewise meet FDA requirements regarding data security, access to data by an authorised user group, keeping an audit trail and the provision of electronic signatures.
Secure temperature limiter
Since an optimum temperature is the most important parameter for the metabolisation of microorganisms or enzymes, the use of safety temperature limiters is a proven method for preventing irreversible damage. The applications of the freely configurable Jumo safety M STB/STW include monitoring thermal processes as well as any situation where functional safety is called for. Its task is to switch off safely when the input signal reaches a critical value. This way, the residual risk to the process, people, machinery and ultimately the system is minimised – without compromising availability and efficiency.
The monitored temperature measurements can be delivered to the Jumo safety M STB/STW at its analogue input either by means of stand-ard signal or from several sensors. If the limit value is exceeded, the system’s relay output switches to a safe operating state and the status LEDs change to red. The high safety requirements of DIN EN 61508 and DIN EN 13849 are met by a device concept which guarantees reliable error detection with its 1oo2D (1 out of 2 diagnosis) structure. The safety temperature monitor and limiter are approved according to SIL, PL (Performance Level) and UL. They can accordingly be used, for example, in applications governed by the Machinery Directive (2006/42/EC).
The warranted safety of machinery and processes is increasingly important as systems become more complex. Thanks to innovative so-lutions for sensors and automation incorporating electronics and hardware with suitable safety architecture – such as the Jumo safety M STB/STW safety temperature monitor and limiter described here – processes in the future-oriented field of white biotechnology can be monitored at the highest level.
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