Effects of sodium nitrate on the growth and proximate composition of the indigenous marine microalgae Tetraselmis chuii (Butcher, 1959)Sanzib Kumar Barman, Helena Khatoon, Mohammad Redwanur Rahman, Sabuj Kanti Mazumder, Shanur Jahedul Hasan
Nitrogen is one of the fundamental nutrients for algal growth, underpinning the microalgal biochemical composition. Therefore, this study compared the growth and proximate compositions of Tetraselmis chuii (Butcher, 1959), cultured in different nitrate (NaNO3 ) concentrations (25, 50, 100, 200 and 500 mg L-1). Thus, the cell density, optical density, specific growth rate and division rate of T. chuii were measured daily. Furthermore, protein and carbohydrate contents were also determined in the stationary phase. The results showed that T. chuii cultivated in a NaNO3 concentration of 500 mg L-1 had significantly (p<0.05) higher growth in terms of cell density, biomass, optical density, specific growth rate and division rates compared with other concentrations. Likewise, protein content was also significantly higher under the NaNO3 concentration of 500 mg L-1, whereas significantly (p<0.05) higher carbohydrate content was found at 25 mg L-1 NaNO3 compared with the other concentrations, showing a contrary trend between protein and carbohydrate concentrations, respectively. Since the primary focus has been on improving the quality of microalgal biomass in order to develop novel processes and products, this is the first study to use higher concentrations of modified nitrate on T. chuii isolated from the coastal area of Bangladesh. Thus the indigenous marine T. chuii had significantly utilised NaNO3 concentrations with higher growth and proximate contents in this study. However, further study is needed on microalgal genetics and metabolic engineering to create a new molecular era of the indigenous marine microalgae isolated from the coastal water of Bengal.