Turbidity: Optimize continuous biomass monitoring with Mettler-Toledo Ingold

Background
In fermentation processes the cell concentration is typically measured off-line via optical density (OD) measurements. Samples are drawn from the fermenter and the optical density is measured in a bench-top spectraphotometer at defined conditions:

- Wavelength, typically one in the range from 400…700 nm
- Cuvette diameter (= optical path length), typically 10 mm
- Dilution factor.

For higher concentrations it is necessary to dilute the sample in order to get reasonable results. The optical density of the high concentration sample is then back calculated, i.e.: a sample diluted twenty times exhibits an OD reading of 0.5. The OD of the original sample is indicated with 10.

Because samples are drawn from the fermenter and require dilution, the OD method proves to be time consuming and will not provide a continuous picture of cell growth throughout the fermentation…..

Please open the below pdf-file to read the entire «Application Note»!