The effect of zirconium oxide nanoparticles on dehydrogenase and hydrolytic activity of activated sludge microorganisms

The pervasive use of engineered nanoparticles (NPs) in a wide range of fields raises concerns about their potential environmental impacts. The impact of NPs on the activity of enzymes in sewage sludge was examined using model engineered zirconium oxide nanoparticles (nano-ZrO2). Dehydrogenase activity was evaluated with the TTC test and hydrolytic activity with FDA test. In this study an inhibitory or a stimulating effect of NPs on the activity of the enzymes was observed. The levels of inhibition/stimulation of the nano-ZrO2 varied in relation to duration of contact NPs with activated sludge and particle size (nano, bulk).