Effects of sodium nitrate on the growth and proximate composition of the indigenous marine microalgae Tetraselmis chuii (Butcher, 1959)

Abstract

Nitrogenisoneofthefundamentalnutrientsforalgalgrowth,underpinningthemicroalgalbio-chemical 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.chuiiweremeasureddaily.Furthermore,proteinandcarbohydratecontentswerealsodeter-mined in the stationary phase. The results showed that T. chuii cultivated in a NaNO3 concentration of500mgL-1hadsignificantly(p lt;0.05)highergrowthintermsofcelldensity,biomass,opticaldensity, specific growth rate and division rates compared with other concentrations. Likewise, pro-tein content was also significantly higher under the NaNO3 concentration of 500 mg L-1, whereas significantly (p lt;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 concentra-tions, respectively. Since the primary focus has been on improving the quality of microalgal bio-mass in order to develop novel processes and products, this is the first study to use higher concen-trationsofmodifiednitrateonT.chuiiisolatedfromthecoastalareaofBangladesh.Thustheindigenous marine T. chuii had significantly utilised NaNO3 concentrations with higher growth and proximatecontentsinthisstudy.However,furtherstudyisneededonmicroalgalgeneticsandmetabolic engineering to create a new molecular era of the indigenous marine microalgae isolated from the coastal water of Bengal.

Keywords

• nitrogen concentrations
• marine microalgae
• growth
• proximate composition