Effect of Low-Temperature Preservation on Growth Characteristics of Marine Microalga Nannochloropsis salina

The present study aimed to preserve the microalgae, at three different temperatures (0, -4 and -20 ) Nannochloropsis salina following standard protocols and assess their viability and growth characteristics upon thawing.The algal cells were preserved in Conway medium following seven different treatments: 0 without addition of cryoprotectant, -4 without cryoprotectant, -4 with 5 and 10% Me SO 2 and -20 with 5 and 10% Me SO along with a control at room temperature (24 ) for 5 days.Upon air thawing, the cells were sub-cultured at 2 optimum conditions and were analyzed for the growth characteristics, viz., biomass, specific growth rate, cell density and optical density for 5 days.Among the treatments, the sample preserved at -4 without addition of any cryoprotectant exhibited better performance in terms of biomass (0.0165 g/ml), optical density (0.0265) and cell density (4.78 x 10 cells/ml).Similarly, the cells preserved at -20 with 10% 5 cryoprotectant exhibited poor growth performance in terms of cell density (1.86 x 10 cells/ml) and biomass (0.0085 g/ml) which may be 5 attributed to the toxicity of cryoprotectants.Thus, can be preserved at -4 without adding any cryoprotectant.This Nannochloropsis salina eliminates the need to maintain continuous sub-cultures in aqua hatcheries, which is laborious and costly.