Secondary metabolites production combined with lead bioremediation by Halamphora sp. marine diatom microalgae and their physiological response

Abstract

This study was designed to investigate the physiological and biochemical response of the diatom microalgae Halamphora sp. (SB1 MK575516.1) to the toxicity of lead (Pb) as well as its ability as phytoremediation. Four different concentrations of Pb (50, 100, 150, and 200 mg L-1) were applied for 10 days. Fatty acid profile, mineral composition, secondary metabolite contents, and physiological responses have been determined in Halamphora biomass. We found that this metal was mainly removed by bio adsorption on cell surfaces and that Halamphora sp. could acclimatize upon long-term exposure to Pb stress. A decrease in the cell’s number and size, polyunsaturated fatty acids as well as mineral content in Halamphora sp were observed under Pb stress. However, an increase in polyphenol, flavonoid, and carotenoid contents has been recorded at 100 mg Pb L-1, with stimulation of the antioxidant capacity as measured by DPPH and ABTS radical scavenging activities. An increase in MDA, proline, and H2O2 levels were also observed. On the other hand, the deleterious effect of Pb resulting from the cellular oxidative state can be alleviated by the enzymatic system such as Superoxide dismutase (SOD), Glutathione peroxidase (GPx), and catalase (CAT). The present study indicates the ability of Halamphora sp. to remove heavy metals from the aquatic environment and produce antioxidant biomolecules.