Sodium chloride and nitrogen effects on Chlorella vulgaris growth and biocommodities production

Environmental conditions can affect the growth and biomass production of microalgae. Microalgae species react differently to changes in growing conditions. The aim of the present study was to investigate the effect of sodium chloride on Chlorella vulgaris cultured in 1/3 N BG-11 medium supplemented with different NaCl concentrations (0 to 35 g/L) in 2 L glass flasks. The algal growth was similar in cultures with 1 and 3.5 g/L NaCl and was 5 to 15 times higher compared to cultures in 15 and 35 g NaCl/L. Nitrates consumption by C. vulgaris was increased by the increase of salinity, while the opposite was observed for soluble phosphorus. The increase of salinity resulted in higher content of lipid, proteins and sugars. The combination of salinity and nitrates stress was fully examined in this study. During nitrate starvation, a remarkable increase of soluble phosphorous was observed and the culture with the highest NaCl concentration (35 g/L) exhibited the high -est soluble phosphorus concentration approaching 50 mg/L. Nitrates starvation resulted in the increase of lipid (22%-57%), protein (13%-27%) and sugars (12%-56%) content and the higher the NaCl the higher protein and sugar content.