Effect
of TiO<sub>2</sub> Nanoparticles and UV Radiation
on Extracellular Enzyme Activity of Intact Heterotrophic Biofilms
- Publication date
- Publisher
Abstract
When
introduced into the aquatic environment, TiO<sub>2</sub> NP
are likely to settle from the water column, which results in increased
exposure of benthic communities. Here, we show that the activity of
two extracellular enzymes of intact heterotrophic biofilms, β-glucosidase
(carbon-cycling) and l-leucin aminopeptidase (nitrogen-cycling),
was reduced following exposure to surface functionalized TiO<sub>2</sub> NP and UV radiation, depending on the particles’ coating.
This reduction was partially linked to ROS production. Alkaline phosphatase
(phosphorus-cycling) activity was not affected, however in contrast,
an alkaline phosphatase isolated from <i>E. coli</i> was
strongly inhibited at lower concentrations of TiO<sub>2</sub> NP than
the intact biofilms. These results indicate that enzymes present in
the biofilm matrix are partly protected against exposure to TiO<sub>2</sub> NP and UV radiation. Impairment of extracellular enzymes
which mediate the uptake of nutrients from water may affect ecosystem
function
