I need to standardize the growth phases of yeast cells as quick as possible. However, with the plate count and haemocytometer method due to the large no. of isolates. So, can anyone provide me with any standard chart for determination of cell no. based on spectrophotometric measurement?
There is no standard curve for correlation of OD and cell number, except you make one yourself for exactly your cells. The reason is that the light scattering ('optical density') of cells is not only dependent on cell number but also on size, shape, granularity and other very individual factors. Determine your cell number by plate count or FCM and correlate it to OD (works only if your cultivation is always the same).
Do you know the Mc farland standard that you can obtain with sulfuric acid 1% and barium chloride? This method may be not very exact because different cells could stop the light in different way but at the beginning you can confront yours results obtained for your sample using the plate method and the spectrophotometric one and so you can calibrate the mac Farland methods for your cells . Bye
I don not know the standard chart for determination of cell no based on spectrophotometric measurement.you may consider the flow cytometry method,which based on fluorescent probe.
ok, thank you for your support. Ill search for the Mc Farland method. however, there could be a problem with flow cytometry method.
There is no standard curve for correlation of OD and cell number, except you make one yourself for exactly your cells. The reason is that the light scattering ('optical density') of cells is not only dependent on cell number but also on size, shape, granularity and other very individual factors. Determine your cell number by plate count or FCM and correlate it to OD (works only if your cultivation is always the same).
I agree with Michael Jahn. Even in the same experiment there are difference between the result of plate count and FCM.
OK, it is going to be a very lengthy work than. Plate count seems to be only way I see.
Hi all,
As Michael suggested, this correlation curve is specific to each and every fermentation as it depends on the medium, the state of the cells (especially if they tend to accumulate kinds of metabolites or reserve carbohydrates and so on), the mode of culture (batch, fed batch, continuous etc.).
If you are performing fermentations applying the same medium, conditions, strain, you can build your own OD vs CFU curve and use it as long as you perform fermentations of the same kind.
Amine
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