Essais de cryoconservation d'algues unicellulaires d'intérêt aquacole.

Cryopreservation tests were carried out for Platymonas "Batan" sp., P. suesica, Isochrysis aff galbana, Chlorella minutissima, Nannochloris occulata, Chaetoceros gracilis and C. "BA" sp. The focus of the protocol was based on the duration of incorporation and cryoprotector concentration (DMSO). Two methods were used to compare the effects of each freezing protocol for algae survival. The first method allows evaluating survival rate through orange acridine coloration and epifluorescence microscope readings. The second one requires culturing each sample and growth curbs are established through daily readings of algal solutions optical density. Freezing the samples was either done directly through liquid nitrogen freezing (-196°C) or through slow freezing, down to -30°C followed by nitrogen immersion. Notably, this second method significantly shortens the latency duration prior to re-growth.