Hello,
I have tried to grow Spirulina using the CCAP Spirulina medium recipe which basically Zarrouk's medium https://www.ccap.ac.uk/media/documents/SP_Spirulina_Medium.pdf. And when I subculture my spirulina in the medium the culture crashed overnight. The only change I did in the medium was not adding Vitamins. Light intensity was 100 uE, day night cycle of 16:8 and temperature 25C. It is my first time growing this species. Any suggestions about what can have gone wrong will be very welcomed!
Thanks,
Maria
Maria, Did you measure medium pH before the inoculation and after its crush? What was the ratio between "old culture" used for the inoculation and new medium?
It is likely that 100 uE were too strong for the newly prepared culture. I would recommend you to use deem light (< 30 uE) for young cultures of cyanobacteria with low density. I will continue when I got your information about pH dynamics. IB
Hi Maria,
although the Spirulina might need the vitamins, I find it hard to believe that this is the cause for an overnight crash. I would expect it would take a few days and slow down growth before they would crash. I agree with Igor that 100 uE might be a bit much: if you inoculated from a dense culture the light shock might be too much, and it would be better to use a low irradiance and than slowly crank it up when the culture grows and get more dense. People should report average light intensities inside the culture in their papers, and not incident light intensities for this reason! And indeed,, check the pH. This is often a course of collapse
Hello Maria,
I join the same idea of Igor and Jacco about the light intensity, i have tried 2500 lux (about 35 uE) and it worked very well. without vitamins spirulina can grow also. I think that the pH would be the cause of collapse, just ajust it to 9 and try again.
wish you good luck
Thank you all for your answers! They have been very useful. I changed the medium (just to be sure that I rule out that) and I put a new inocule to grow at lower light intensities. So far it looks like that it is working!
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