Effect of different nitrogen sources on cell growth and biochemical compositions of Chlorococcum sp. cultivated under laboratory conditions

Abstract

Different sources of nitrogen can affect the growth and biochemical composition of microalgae. The present study was conducted to determine the effect of different nitrogen sources on algal growth, carbohydrate and protein contents, of freshwater microalgae Chlorococcum sp. Three different nitrogen sources were used in this study including sodium nitrate, ammonium chloride and urea. The cultivation of the algae of different nitrogen sources took place in the same parameter conditions (24 hours of light duration; 25 ± 1 °C of temperature; 7.20 ± 0.02 of pH). The algal cells were harvested at the early stationary phase for biochemical analysis. The number of cells were quantified by using a counting chamber (haemocytometer) and growth curves were plotted to determine the growth rate. The results revealed that Chlorococcum sp. cultivated in urea as the nitrogen source exhibited the highest growth rate. Apart from that, it was also found that the cells cultivated in urea displayed the highest carbohydrate and protein content as compared to the other two nitrogen sources which were 25.5% and 18.7%, respectively. Moreover, the cells cultivated in urea were medium in size during early stationary phase indicating urea the best nitrogen source for Chlorococcum sp. under controlled conditions.