The human race has been making use of microorganisms for thousands of years. For example, bacteria, yeast and molds are used to make bread, beer and yogurt, respectively. These tiny forms of life also serve as producers of medicines such as antibiotics and insulin. In order for microorganisms to be able to grow as well as possible, the pH value and the concentrations of glucose and oxygen involved must not exceed or fall below defined thresholds. The process of fermentation is an important production step in this regard. It involves the multiplication of cells that produce either a pharmacological product itself or a precursor substance. The devices and bioreactors used for this are called fermenters. For instance, at Siemens Healthineers’ Laboratory Diagnostics business unit in Marburg, Germany, specialists are using fermenters to cultivate genetically modified bacteria in order to obtain certain proteins. These proteins serve as “active agents” in reagents used to diagnose infectious diseases or problems with blood clotting.
To monitor this process, samples are typically drawn manually with a pipette. The addition of nutrient solutions also takes place manually. “But both of these actions can lead to contamination and imprecision,” says Johannes Österreicher of Siemens Corporate Technology.
Autonomous Process Control
A solution is offered by Siemens’ Autonomous Fermentation Control System (AFCoSY), which enables easy and cost-efficient process control. In contrast to products commonly used in the past, AFCoSY does not require an elaborate system of hoses and pumps. Prior to starting the system, the user merely specifies which parameters must be satisfied. No further intervention is needed during cell growth. Nevertheless, the system is outfitted with a communications module so that conditions can be adjusted during the growth process in order to react to possible changes in microorganism cultures. This module is located in a three-part control head, which fits on any standard shaking flask. These flasks are used during product development in the lab to cultivate microorganisms.
The shaking flask contains a sensor that records measurements, a pump that, for example, drips nutrient fluid from an integrated reservoir into the flask, and an evaluation circuit that controls the entire process. There is also an infrared port through which measurement data can be read. All in all, the system saves time while improving quality, because it prevents contamination and errors that might otherwise occur when adding materials. Furthermore, resource use is minimized , because fewer samples are needed than in the past.
“We’ve also developed a special measurement process that requires only a single sensor,” says Österreicher. “The process determines the pH value, partial pressure of oxygen and glucose values at 15-minute intervals. Normally, at least two separate sensors are needed for that.”
A Step Toward Personalized Medicine?
Among its other uses, Siemens’ Autonomous Fermentation Control System could be important for personalized medicine, which often requires only small quantities of an active agent. One special feature of the system is that the electronic part is removable. The remaining elements can then be sterilized and reused, which is important for applications in the pharmaceuticals industry, in particular.
-> This project has been supported by the Vienna Business Agency (R&D Call: From Science to Products 2013)