Hello,
I have monitored the growth of some microalgal strains along 13 days. I am using a Cell Coulter counter and I made the growth curves by plotting number of cells vs days or tot. volume vs days.
I fitted the logistic curve using R and also calculated the corresponding max average growth rate.
The problem is I got different slopes in the curves for the same cultures depending on which data I use: number of cells or volume.
So, I am not sure which is the correct one to use. I do not trust always the calculated number of cells because for some colonies-forming species, like Scenedesmus or Desmodesmus, it is not easy to determine the correct values, so I rather prefer to use the tot. biovolume measured by the machine. For instance, I got µ=1,06 with number of cells and µ=0,55 with biovolume in Chlorella sorokiniana, which makes me think I have to use the first data, but for Scenedesmus sp. I got µ=1,06 (number of cells) and µ=0,72 (biovolume), and I do not believe I have the same growth rates as in Chlorella, which is a notoriously faster species.
Any suggestion?
Thanks! /Lorenza
There may be error in counting.
You can try out serial dilution of culture and then calculate cfu at different stages.
You can back calculate the number of cells.
Dear Lorenza，
I would use number of cells on condition that the colonies are seperated into individual cells.
You can try ultrasonic disruption before counting.
Of course you have to figure out the optimum time for each species.
I hope this will help you.
Best!
cell counting will give approximate results only..... in your case better you can go for dry biomass estimation or ash free biomass estimation at least for initial and final days, which can give you perfect values and based the values you can calculate growth, which is more reliable one.
you can check biomass of initial up to 13 days using Membrane filter Technique
Good afternoon! I think, that calculation of cells using Cell Coulter counter will be more correct, because Cell Coulter counter will allow in suspensions living and dead cells. It’s important, because only living cells provide biomass buildup. Also increasing of dry biomass weight we can see when the mass of the cells has been increased by cell growth, not only by increasing their concentration after cell division. And specific growth rate of microalgae depends from culture conditions. You should handpick optimal conditions for each kind of microalgae and compare their specific growth rates.
Best regards, Mikhail
Please see the papers for your reference.
Chapter Microalgae Cultivation Using Various Sources of Organic Subs...
Chapter Palm Oil Mill Effluent as an Environmental Pollutant Palm Oi...
Article Evaluation of Lipid Content in Microalgae Biomass Using Palm...
Article Evaluation of Lipid Content in Microalgae Biomass Using Palm... //www.researchgate.net/publication/316675390_Evaluation_of_Lemna_minor_and_Chlamydomonas_to_treat_palm_oil_mill_effluent_and_fertilizer_production
Regards
Ashok
Please see the papers for your reference
https://www.researchgate.net/publication/327381747_Microalgae_Cultivation_Using_Various_Sources_of_Organic_Substrate_for_High_Lipid_Content
Article Evaluation of Lipid Content in Microalgae Biomass Using Palm...
//www.researchgate.net/publication/316675390_Evaluation_of_Lemna_minor_and_Chlamydomonas_to_treat_palm_oil_mill_effluent_and_fertilizer_production
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