Ecotoxic Effects of Cerium Oxide Nanoparticles on Bacteria

In this study, the ecotoxic effects of cerium oxide nanoparticles (CeO2 NPs) on both gram positive Bacillus subtilis and gram negative Escherichia coli bacteria were investigated. CeO2 NPs were prepared in synthetic water solutions having different water contents (low, median and high ionic strength and conductivity, pH 5.5 and 6.5). Bacteria were exposed to CeO2 NP solutions in absence and presence of light conditions for 1 h. Different NP concentrations (10, 100, 500 and 1000 mg/L) were used, and environmental scanning electron microscopy imaging was performed for morphological examination of the bacteria. Results showed an aggregation of NPs relating to both high NP concentrations and high ionic strength of the water solutions. Regardless of the test condition, CeO2 NPs highly inhibited the bacterial growth