Fermentation Control

Fermentation refers to the conversion of organic material by microorganisms such as bacteria, fungi or single-celled organisms or their enzymes. Originally, fermentation was used to describe a biotic reaction in the absence of air. Today, fermentation includes any technical bioreaction. For example, (bio)ethanol as well as medical products such as insulin and a variety of antibiotics are produced on a large scale in bioreactors – so-called fermenters – with the help of microorganisms.

Inline and Online Monitoring

The inline or online monitoring of fermentation processes is becoming increasingly important. The industry is increasingly demanding fast and accurate analytical methods in order to optimize cultivation conditions and reduce fermentation times. For the most part, product-specific analysis is performed offline. However, such a procedure is labor-intensive and expensive. With offline measurements, it is also problematic that there is a time lag between the fermentation process and the analytical result. Especially in batch fermentations, overproduction can lead to by-products and degradation products. Therefore, timely, process-integrated online analysis is important in order to be able to control the fermentation process in a targeted manner. Our Gas and liquid analyzer Vario two. measures volatile substances with an interface to the bioreactor faster, more sensitively and more cost-effectively.

Sample Measurements

In the following section, measurements are shown which have already been carried out in the laboratory with our liquid analyzer Vario one. The liquid inlet of the membrane inlet mass spectrometer allows substances to be measured directly and online from the liquid. A standard membrane is used. Select the application from which you want to view the measurement. Then the associated experiment is displayed with all results and data.

Monitoring of the Ethanol Concentration in a Fermentation Process

The starting materials for bioethanol are the sugars (carbohydrates) contained in plants, which ferment with the help of enzymes from microorganisms or yeast fungi to produce ethanol (potable alcohol). Fermentation is complete when either the sugar is consumed or a maximum alcohol concentration is reached.




Bioethanol Production


Vario one.


In Situ Inlet

Measurement Task

The ethanol concentration was measured with the Vario one. Liquid analyzer in the bioreactor in continuous operation. This is an inline measurement process, so that measurements are taken in real time without any sampling or sample preparation. An in-situ inlet was used here. The course of the ethanol concentration can be easily followed directly on the screen in real time. In the reference measurement, the ethanol concentration was determined by HPLC as an offline analytical method. Here, in contrast to the inline measurement, samples are taken, then subjected to sample preparation in a laboratory and subsequently measured.



The measurement results of the Variolytics technology, which were generated in real time in a fermenter, are confirmed by the reference measurement using (offline) HPLC. This shows that Variolytics’ MIMS technology delivers the same results as long established analytical methods. All this with less time required due to unnecessary sampling and sample preparation and in real time, so that the process can be directly controlled with the generated measurement data.


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Variolytics GmbH

  Meitnerstraße 6, 70563 Stuttgart DE
  +49 711 2525 9620




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