The Influence of Light and Nutrient Starvation on Morphology, Biomass and Lipid Content in Seven Strains of Green Microalgae as a Source of Biodiesel

Abstract

The development of clean and renewable energy sources is currently one of the most important challenges facing the world. Although research interests in algae-based energy have been increasing in the last decade, only a small percentage of the bewildering diversity exhibited by microalgae has been investigated for biodiesel production. In this work, seven strains of green microalgae belonging to the genera Scenedesmus, Tetradesmus and Desmodesmus were grown in liquid medium with or without a nitrogen (N) source—at two different irradiances (120 ± 20 and 200 ± 20 μmol photons m−2 s−1)—to evaluate biomass production and FAME (fatty acid methyl esters) content for biodiesel production. The strains of Tetradesmus obliquus and Desmodesmus abundans grown in N-deprived medium showed the highest FAME content (22.0% and 34.6%, respectively); lipid profile characterization highlighted the abundance of saturated FAME (as C16:0 and C18:0) that favors better viscosity (flow properties) and applicability of biodiesel at low temperatures. Light microscopy and confocal laser scanning microscopy observations were employed as a fast method to monitor the vital status of cells and lipid droplet accumulation after Nile red staining in different culture conditions.

Effect of High Cell Density to Lipid Content Microalgae Chlorella vulgaris on Photoautotrophic Cultivation

“…The high-density treatment aimed at giving starvation effect to microalgae cells under growth conditions was not proven to accumulate more lipids than the control treatment. Nutrient starvation can decrase biomassa productivity but increase the lipid content of the microalgae (Rugnini et al, 2020). In this study, nutrient starvation treatment approach with the high cell density method reduced the biomass productivity but was not proven to increase the lipid acumulation of Chlorella vulgaris.…”

In Vitro Characterization of Antioxidant, Antibacterial and Antimutagenic Activities of the Green Microalga Ettlia pseudoalveolaris

“…Additionally, in a very recent FAs profile analysis of Chlorella vulgaris , in each of the four different strains examined, palmitic acid resulted the most representative among the SFAs [ 39 ]. Another study on other green microalgal strains ( T. obliquus and D. abundans ) showed that SFAs represent most of total fatty acid methyl esters profile, confirming that many microalgae are rich in this type of FAs [ 40 ]. Additionally, E. pseudoalveolaris proved to be rich in polyunsaturated fatty acids (PUFAs), particularly in alpha-linoleic acid (ALA) (29.28 ± 0.12%) and linoleic acid (LA) (14.95 ± 0.06%), in accordance with what observed in Chlorella vulgaris by Mauricio et al [ 39 ].…”

Chlamydomonas agloeformis from the Ecuadorian Highlands: Nutrients and Bioactive Compounds Profiling and In Vitro Antioxidant Activity

“…Notably, a recent analysis of the FA profile of Chlorella vulgaris across four distinct strains and of Ettlia pseudoalveolaris highlighted palmitic acid as the predominant SFA [31,38]. Moreover, investigations on other green microalgal strains, namely T. obliquus and D. abundans, showed the prevalence of SFAs as the primary constituents in their total fatty acid methyl esters profiles, reaffirming the richness of this FA type in numerous microalgae [39]. It Is important to take into account that the values of the centesimal composition of microalgae can vary within the same species based on the cultivation method, collection timing, and environmental stress factors.…”