GROWTH OF DUNALIELLA-VIRIDIS TEODORESCO - EFFECT OF SALINITY, TEMPERATURE AND NITROGEN CONCENTRATION

The growth of a strain of D. viridis has been studied in batch culture under different combinations of temperature, salinity and nitrogen concentrations. Changes in these variables have a significant effect on cell division, biomass production, cell volume and pigment yield. This strain grows optimally at 1 M NaCl and 30-degrees-C. Increasing salinity up to 4 M NaCl leads to a significant decrease of cell division rate and maximal population; growth at lower temperature decreases the rate of division of the cells but increases maximal cell density. Pigment yield decreases with increasing salinity and increases with increasing temperature. Nitrogen concentration has a large effect on total cell biomass and pigment production, but not on cell division rate. Saturation of growth occurs at 5 mM NO3-; higher concentration (e.g. 10 mM) leads to a decrease of maximal cell density and photosynthetic pigment content.