Microalgae are attracting particular attention because of their use in various fields such as bio-energy. The main objective of this work was to evaluate the effect of stress induced by nitrogen deficiency on the accumulation of lipids in Chlorella sp. and Chlamydomonas sp. isolated from the brackish water of El Golea Lake in the Algerian Sahara. The two species were first cultured in batch in BBM medium under basic conditions (0.75 g/l NaNO

3 ) then under nitrogen stress (0.25 g/l NaNO

3 ). After lipids extraction, the fatty acids were trans-esterified to obtain the fatty acid methyl esters that constitute biodiesel and which can be analyzed by GC-FID chromatography. CG-FID analysis of fatty acids in the four cultures showed that the two species react differently to nitrogen depletion. In Chlorella a slight decrease in the total fatty acid content was obtained in the stressed culture while in Chlamydomonas nitrogen stress caused an increase in the fatty acid content from 24.06 to 31.10 µg/mg of dry matter. The results obtained in terms of algal biomass and fatty acid composition constitute basic elements for a possible exploitation of the species in bioenergy.

Article History

Received: Nov 14, 2023; Accepted: May 23, 2024; Published: Jun 30, 2024

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