Understanding the Effect of Free Nitrous Acid on Biofilms

Mariella Chislett, Zhigang Yu, Bogdan C. Donose, Jianhua Guo, Zhiguo Yuan*

*Corresponding author for this work

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

15 Citations (Scopus)

Abstract

Free nitrous acid (FNA, i.e., HNO2) has been recently applied to biofilm control in wastewater management. The mechanism triggering biofilm detachment upon exposure to FNA still remains largely unknown. In this work, we aim to prove that FNA induces biofilm dispersal via extracellular polymeric matrix breakdown and cell lysis. Biofilms formed by a model organism, Pseudomonas aeruginosa PAO1, were treated with FNA at concentrations ranging from 0.2 to 15 mg N/L for 24 h (conditions typically used in applications). The biofilms and suspended biomass were monitored both before and after FNA treatment using a range of methods including optical density measurements, viability assays, confocal laser scanning microscopy, and atomic force microscopy. It was revealed that FNA treatment caused substantial and concentration-dependent biofilm detachment. The addition of a reactive nitrogen species (RNS) scavenger, that is, 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, substantially reduced biofilm dispersal, suggesting that the nitrosative decomposition species of HNO2(i.e., RNS, e.g., NO + NO2) were mainly responsible for the effects. The study provides insight into and support for the use of FNA for biofilm control in wastewater treatment. © 2022 American Chemical Society. All rights reserved.
Original languageEnglish
Pages (from-to)11625-11634
JournalEnvironmental Science and Technology
Volume56
Issue number16
Online published1 Aug 2022
DOIs
Publication statusPublished - 16 Aug 2022
Externally publishedYes

Research Keywords

  • biofilm
  • free nitrous acid
  • Pseudomonas aeruginosa
  • reactive nitrogen species

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