Growth performance and biochemical composition of marine microalgae Dunaliella tertiolecta exposed to selenium nanoparticles

Selenium (Se) is a natural trace element which has large positive and negative environmental impacts that may alternate from an essential micronutrient to a toxic compound within a narrow concentration level. Investigation of selenium nanoparticles (SeNPs) as a possible source of selenium has just recently begun. They have received a lot of attention due to their lower toxicity when compared to sodium selenite (Na2SeO3). Although higher doses of SeNPs may have a negative impact on different processes in algae, lower doses can increase algal biomass without any toxic cellular effect. The objective of this study was to investigate the effects of different SeNPs concentrations on marine microalgae Dunaliella tertiolecta. Algae were cultured under a wide range of different SeNPs concentrations up to 14 days, followed by determination of chlorophyll a, total lipid and protein content, as well as composition of fatty and amino acids. The results have shown that lower concentrations caused a significant increase of biomass concentration and chlorophyll a content, contrary to results obtained in samples with higher SeNPs concentrations. Total protein content and productivity were similar at all tested SeNPs concentrations. Fatty acids, determined by using gas chromatography (GC), had higher content of unsaturated fatty acids in all tested samples. These results provide a better understanding of the effect of SeNPs on green microalgae, which may help in the development of new biotechnological applications considering that nanotechnology becomes a promising tool in many fields of research.