Microalga Scenedesmus bijugus: Biomass, lipid profile, and carotenoids production in vitro

Abstract

Manipulating specific nutrients in growth media to boost production of lipids or carotenoids in microalgae is a widespread practice; however, it decreases overall biomass productivity, an important consideration for viable production of biofuels. In the present study, maximum productivity of lipids (117.01 mg/L/d) and biomass (249.60 mg/L/d) was obtained on day 13 in Bold's basal medium (BBM) modified by adding 25 mM NaCl and 20 μM phosphate. Lutein and astaxanthin productivity was, however, only slightly different from that in the standard medium, namely blue-green-11 (BG-11). The lipids profile was dominated by C16:0 and C 18:1 fatty acids ranging from 26.69 to 39.32% and 10.8–35.31% (palmitic and oleic acids) in all the five variants of the culture medium. These results indicate that the highest proportion of saturated fatty acids (SFA; 61.02%) was obtained in BG-11 whereas that of monounsaturated fatty acids (MUFA; 37.34%) was obtained in BBM supplemented with NaCl (50 mM) and phosphate (20 μM). All the five variants led to lipids suitable for biodiesel production, marked by a lipid profile dominated by the two fatty acids. It is concluded that making the culture medium more saline and enriching it with phosphates increased lipid and biomass productivity and the synthesis of fatty acids methyl esters (FAME).