Effect of the Culture Nutrients on the Biomass and Lipid Productivities of Microalgae Dunaliella tertiolecta

Abstract

This work analyses the influence of macro and micronutrients on the growth, biomass and lipid productivities of Dunaliella tertiolecta (D. tertiolecta), showing that with the exception of Nitrogen (N) and Iron (Fe), the other nutrients added to the culture medium - Magnesium (Mg), Potassium (K), Manganese (Mn) and Zinc (Zn) - did not influence the studied parameters. The best maximum and average drybiomass productivities were respectively 141.8 mg/L/d and 63.1 mg/L/d, obtained in the 5th day of the test, by increasing the N concentration 10 times in comparison to the standard culture medium “artificial seawater medium with vitamins”. In these conditions, the lipid content and maximum lipid productivity were respectively 33.5 % and 47.4 mg/L/d, corresponding to more than three times the value in the standard conditions (13.3 mg/L/d). Also, by increasing the Fe concentration 10 times in the culture medium, themaximum lipid productivity increased to almost the double, i.e. from 14.6 mg/L/d to 28.0 mg/L/d, obtained in the 28th day of the test. Therefore, N and Fe addition to the culture medium resulted in a significant increase in lipid productivity, suggesting that residual wastewaters rich in N or Fe could be used tocultivate D. tertiolecta for lipid production.