Dear Mr Ilyes,

The growth rate can be determined by 1. OD 2. Cell No and 3. Biomass (for the filamentous organism) at the periodical interval.

The absorbance maxima depend and varies on individual algal species. If you have a multimode reader, 5 or 8 different readings (wavelength) can be taken simultaneously.

The plate reader is ideal, timesaving, and very robust for the same organism's different treatments (Media engineering for specific metabolites).

After obtaining the above parameters, you can find out the specific growth rate (SGR), which is the parameter used to decide the growth pattern.

Hope it is clear and helpful for your experiment.

Best regards,

Arumugam Muthu thank you for your reply. If I've understood correctly, I need to scan the suspensions of each strain separately with a spectrophotometer, to determine the maximum absorption wavelength for each strain in my collection, then use these wavelengths to read my cultures on microplates?

The OD will increase with cell number as the culture gets dencer. You can calibrate the OD to cell number with cell counts at different cell numbers - giving a OD to cell number graph. After that it is easy to read your plates and interpret the OD to cell number.

Barry C Smith Thank you Barry for your response. However, could you tell me the ideal wavelength on the plate reader that I could use to read the OD of all the strains in my collection, considering that the strains have not yet been identified. Thank you very much.

I think the wavelength 540 nm which is not absorbed much by chlorophyll a or b.