Development of a Strategy for Enhancing the Biomass Growth and Lipid Accumulation of sp. UJ-3 Using Magnetic FeO Nanoparticles.

In this study, magnetic FeO nanoparticles (NPs) were used as an effective enhancer to increase the biomass and total lipid production of sp. UJ-3. It was found that the biomass of algal cells increased significantly when they were exposed to low concentrations of FeO NPs (20 mg/L), while the best total lipid content of algal cells was achieved when they were exposed to high concentrations of FeO NPs (100 mg/L). Therefore, we established a strategy to promote the growth and lipid accumulation of microalgae by initially exposing the algal cells to low concentrations of FeO NPs and then treating them with an increased concentration of FeO NPs after 12 days of culture. For this strategy, the biomass and total lipid production of algal cells increased by 50% and 108.7%, respectively, compared to the untreated control. The increase in lipid production and change in the fatty acid composition of Chlorella cells were found to help them to cope with the increased number of reactive oxygen species produced due to oxidative stress in alga cells after the addition of FeO NPs. This study provided a highly efficient way to improve the lipid production of microalgae using nanoparticles.