Effect of TiO2 Nanoparticles and UV Radiation on Extracellular Enzyme Activity of Intact Heterotrophic Biofilms

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• 作者：Hannah Schug ; Carl W. Isaacson ; Laura Sigg ; Adrian A. Ammann ; Kristin Schirmer
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：October 7, 2014
• 年：2014
• 卷：48
• 期：19
• 页码：11620-11628
• 全文大小：426K
• ISSN：1520-5851

文摘

When introduced into the aquatic environment, TiO₂ 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, 尾-glucosidase (carbon-cycling) and l-leucin aminopeptidase (nitrogen-cycling), was reduced following exposure to surface functionalized TiO₂ NP and UV radiation, depending on the particles鈥?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 E. coli was strongly inhibited at lower concentrations of TiO₂ NP than the intact biofilms. These results indicate that enzymes present in the biofilm matrix are partly protected against exposure to TiO₂ NP and UV radiation. Impairment of extracellular enzymes which mediate the uptake of nutrients from water may affect ecosystem function.