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EFFECT OF NITRATE, PHOSPHATE, SALINITY CONCENTRATION AND GROWTH PHASE ON THE BIOMASS AND FATTY ACID CONCENTRATION OF Nannochloropsis oculata (Droop) D.J.Hibberd 1981

 In this study, the effect of nitrate, phosphate concentration, salinity level and phases of the growth curve on the biomass and fatty acid of Nannochloropsis oculata were invesigated. Guillard and Ryther`s modified f/2 media was used as the culture media with different sodium nitrate (220.5, 441.0, 882.0, 1323.0µM), sodium phosphate (9.1, 18.1, 36.2, 54.3µM), different salinity levels (20, 25, 30, 35‰) and different phases (lag, logarithmic, stationary and late stationary). The maximum biomass, 95.93 mg/L was reached in 1323 µM nitrate concentration, 99.74 mg/L was reached in 54.3µM phosphate concentration, 214.39 mg/L was reached  in 30‰ salinity level and 282.76 mg/L was reached in the stationary phase. The biomass and fatty concentration tends to increase proportionally with the increase of the growth phase and salinity level, the maximum fatty concentration, 9.8% of dry weight (DW) was reached in 30‰ salinity level and 9.5% DW was reached in the stationary phase. The highest fatty concentration, 9.3% DW, 8.7% DW was reached in 220.5µM nitrate concentration and 18.1 µM phosphate concentration respectively. The results of this study indicated that PUFAs fatty acids (eicosapentaenoic aicd C20:5n-3 (EPA), docosapentaenoic acid C22:6n-3 (DHA), alpha-linolenic acid 18:3n-3 (ALA), arachidonic acid C20:4n-6 (AA) were high (24.82-25.77% of total fatty acid) when cultured at the stationary phase, 30‰ salinity level and 441µM nitrate concentration.

Key words: Nannochloropsis oculata, Biomass, Fatty acid, Growth phase, Nitrate, Phosphate, Salinity.