Inhibition of the activated sludge-associated enzyme phosphatase by transition metal oxyanions

1Citations
Citations of this article
8Readers
Mendeley users who have this article in their library.

Abstract

Organic esters of phosphoric acid and other organophosphorous compounds are enzymatically hydrolyzed during wastewater treatment by microbial phosphoesterases, especially by phosphomonoesterase (phosphatase). For physiological reasons, the enzyme is inhibited by its main inorganic reaction product, ortho-phosphate. It is known that oxyanions of transition metals, resembling the molecular topology of ortho-phosphate, e.g. vanadate and tungstate, are more potent inhibitors for microbial alkaline phosphatase than phosphate. To proof this effect for activated sludge, a multitude of samples from a communal wastewater treatment plant was exposed at pH values from 7.00 to 8.50 to tungstate, vanadate, and molybdate. Inhibition effects were determined by a sensitive fluorimetric microplate assay and characteristic parameters (IC50 and IC20 concentrations) were deduced from modelled dose-response functions. Mean inhibitor concentrations (in brackets: ranges) causing 50% inactivation (IC50) at pH 7.50 were 2.5 (1.3–4.1) μM tungstate, 2.9 (1.6–5.5) μM vanadate, and 41.4 (33.6–56.7) μM molybdate. Vanadate and tungstate concentrations between 0.6 and 0.7 μM provoked a 20% (IC20) inhibition. The inhibition efficiency of tungstate and molybdate decreased with increasing pH, whereas vanadate reacted pH independently. These results underline the necessity to consider enzyme inhibition assessing the limitations and potentials of biological wastewater treatment processes.

Cite

CITATION STYLE

APA

Böger, B., Wacht, M., Leuck, M., Vilhena, R. de O., Riese, M., & Fischer, K. (2021). Inhibition of the activated sludge-associated enzyme phosphatase by transition metal oxyanions. Water Science and Technology, 83(11), 2629–2639. https://doi.org/10.2166/wst.2021.172

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free