Laboratory fermenter
Laboratory fermenters or laboratory bioreactors are fermenters in the ml to liter scale that are used for bioprocess optimization (optimization of strains, nutrient media, operating modes, etc.).
The laboratory fermenter (also small culture system, research fermenter, pilot fermenter) is, like the production fermenter, a reactor in which the necessary basic procedural operations (temperature control, stirring, gassing, dosing etc.) for cultivating microorganisms (fungi, bacteria) and cell cultures (plant and animal cells) ) can be carried out.
The advantages of the reduced scale are savings in media consumption, lower energy and space requirements, and easier sterilization in the autoclave . The reactors used are partly scaled down fermenters , partly special vessels adapted to the respective task.
Because of the time savings that can be achieved, laboratory fermenter systems are increasingly being designed as parallel reactor systems with four to 16 reactors.
Erlenmeyer flasks , which are placed on shaking machines for stirring, are used in particularly large numbers . These are also referred to here as shake flasks. Shaking is the gentlest form of stirring, which is why shake flasks are also used for shear-sensitive cultures such as animal cell cultures. The classic shake flask is closed with a gas-permeable sterile barrier (e.g. cotton plug). The course of the culture could previously only be analyzed using samples taken manually at certain time intervals. Today, online measuring systems are also available which enable the parallel determination of several metabolic parameters, including oxygen and pH.
Modern laboratory fermenters are now equipped with sensors, dosing and automatic sampling. For example, the oxygen transfer rate (OTR) and the carbon dioxide transfer rate (CTR) and the respiratory quotient (RQ) calculated from them can be measured as universal metabolic parameters and the pH environment can be monitored. This is why most of the tests that previously had to be carried out in fermenters with exhaust gas analysis can now be carried out inexpensively on a laboratory scale.
Laboratory fermenters based on shake flasks have, in addition to gentle stirring, the advantage over conventional fermenters that they can be prepared quickly and easily. They are therefore particularly suitable as reactors in parallel fermentation systems.
literature
- Rudolf W. Kessler (ed.): Process analysis: strategies and case studies from industrial practice. 1st edition. Wiley-VCH Verlag, Weinheim 2006, ISBN 3-527-31196-3 , p. 524.
- K. Schneider, V. Schütz, GT John, E. Heinzle: Optical device for parallel online measurement of dissolved oxygen and pH in shake flask cultures. In: Bioprocess Biosyst Eng. Volume 33, Number 5, 2010, pp. 541-547. doi: 10.1007 / s00449-009-0367-0 , PMID 19701780 .