I have been trying to cultivate some terrestrial Nostoc sp. in liquid BG11. After a few months at ambient temperature and light, I have a nice Oscillatoriale in my flask! Not so bad, but not what I expected... Would any one have any suggestions to enhance the cultivation of terrestrial Nostoc? Can a solid and nitrogen free medium be better?
as you are targeting nostoc sp. you have to cultivate nitrogen free iBG 11 media. try to check media pH periodically. Temp. should be 26-30. light intensity 50 -75 lux. one more thing is that you have to remove bacterial contamination as well as diatom contamination. Hope you will cultivate your nostoc successfully.
After the first few days, when you see that the inoculum starts to grow, you can add CO2 to the atmosphere of the chamber where you have your flasks. Also the light it is very important. Start with very low light intensity and then increase it while the culture grows. The relation between light intensity and culture density, to have the best growing rate, is affected by several things, like the flasks you use, the age of the culture, its characteristics, etc.. BG11 medium is usually better than BG11-0 (without nitrogen) but this last is better if you want to reduce the possibility of contamination for your culture.
When the culture is growth, in a small flask you can use a small bioreactor to increase the growing rate, following all the parameters: Temperature, insufflation, pH, light, etc..
In some rare case we have also used the soil, sterilized, and deionized water in petri plates, in order to replicate exactly the same conditions where the cyanobacteria growing in nature (substrate and rain). In this case you have to pay attention to the humidity rate.
Good luck
yes of course, please use a nitrogen free medium. sometimes it is also usefull to grow them on BG11 with 0.9 % of Agar and of course, without nitrogen. low light intesities (100-150 µmol photons/m² sec PAR) are helpfull as well.
Its true that heterocystous (nitrogen-fixing) cyanobacteria can be grown in nitrogen free medium to reduce/eliminate other non-nitrogen-fixing cyanobacterial growth and also to retain the strain's genetic stability. However, to achieve the growth/biomass for most nitrogen fixing cyanobacteria (at least for developmental study) are grown in standard medium containing nitrate as combined nitrogen source, but some strain prefer to grow in alternate nitrogen source like ammonium nitrogen. More importantly, there are some Nostoc spp. especially N. commune (ball forming cyanobacteria) does not grow in liquid medium at all, and they need solid support for their growth that can be provided by 1.5-1.8% (w/v) agar in the complete growth medium.
Ok thank you every one for your interesting and very helpful answers!
I cultivate cyanobacteria with BG11 medium but my freshwater cyanobacteria are. Already cultivated including Nostoc.
Hi
But why without the Nitrogen? I have been trying to find out a paper that explains how does it work.
Thanks
Soil Nostoc can be easily isolated on BG11o agar, supplemented with cyclohexamide (to avoid algae and fungi). Use diltion series at least to10-4 -10-6 As Nostoc a nitrogen-fixer itself, BG11o will be the best way to get rid off non-fixers (like oscilatorians). When you picked a colony, pin-head sized, it can be easily propagated in liquid BG11o, but use very small volumes at first (5 ml in a tube).Never add any nitrogen. Nostoc will manage just fine. Do not use too much light- 30-60 microensteins will be just comfortable.
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