Assessment of the Potential of Using Microalgae from the Genus Desmodesmus for the Bioremediation of Water Polluted with TiO2 Nanoparticles

The increasing demand for products manufactured using nanotechnology contributes to a major increase in the synthesis of nanoscale materials and their inflow into the aquatic environment. TiO₂ nanoparticles as micropollutants in the aquatic environment directly affect many living organisms with generally negative effects. Microalgae have proven efficacy in bioremediation, which makes them a potential agent for the bioremediation of nanoparticles from wastewater. Evaluation of the capacity of microalgae from the genus Desmodesmus for the bioaccumulation of TiO₂ nanoparticles is carried out and the degree of resistance of microalgae cells to the action of environmentally relevant concentrations of these nanoparticles is determined. Spherical TiO₂ nanoparticles with a size of 30–40 nm are used. It is found by flow cytometry that TiO₂ nanoparticles at concentrations of 10, 100, and 1000 μg/L have no significant effect on the viability of microalgae cells and level of oxidative stress. Nanoparticles at a concentration of 1000 µg/L increase the concentration of photosynthetic pigments by 18–33% by day 13 of the experiment. Desmodesmus sp. appears to be a culture relatively resistant to nanoparticles; the increased bioaccumulation of titanium by microalgae cells in the experimental groups is detected by ICP-MS. All this indicates the significant potential of Desmodesmus sp. for the removal of nanostructured pollutants from the aquatic environment.