Mechanistic model of the Escherichia coli inactivation by solar disinfection based on the photo-generation of internal ROS and the photo-inactivation of enzymes: CAT and SOD

María Castro-Alférez, María Inmaculada Polo-López, Javier Marugán, Pilar Fernandez-Ibanez

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

A mechanistic model of the inactivation of Escherichia coli by solar water disinfection (SODIS) technique ispresented. Bacterial inactivation by SODIS is commonly attributed to the oxidative stress generated bysynergy among solar radiation (UV photons) and mild temperature. Photons may increase the naturallyoccurring amount of internal Reactive Oxygen Species (ROS), such as hydroxyl radical (HO�) and superoxideradical (O2 ��). ROS attacks to different targets inside the cells are one of the main sources of oxidativedamage over cells. Besides, photons may damage the two essential enzymes of the defense systemagainst intracellular oxidative stress, catalase (CAT) and superoxide dismutase (SOD). Therefore, theproposed model is a simplified approach of the complex processes occurring inside cells during SODIS,which is based on the photo-induced formation of intracellular ROS and the photo-inactivation of CATand SOD. The model considers two individual volume units in which the processes are occurringsimultaneously: (i) a single cell (mass balances for intracellular ROS and enzymes) and (ii) the reactor(mass balance for bacteria).Kinetic constant from literature were used, meanwhile CAT photo-inactivation kinetic constant wasdetermined experimentally, (1.50 ± 0.04)�107 cm3 Einstein�1. Model regression was done usingexperimental data of E. coli inactivation by solar disinfection at different controlled conditions of solarirradiance and initial bacterial concentration. The good fit of the simulated and experimental resultssuggested that the mechanistic process proposed is a realistic approach of the disinfection process.Moreover, simulations of the time profile of intracellular ROS and enzymes involved during bacterialinactivation by SODIS are also presented.
Original languageEnglish
Pages (from-to)214-223
JournalChemical Engineering Journal
Volume318
Early online date23 Jun 2016
DOIs
Publication statusE-pub ahead of print - 23 Jun 2016

Keywords

  • E. coli
  • SODIS
  • Mechanistic model
  • ROS-formation
  • SOD
  • Catalase

Fingerprint Dive into the research topics of 'Mechanistic model of the Escherichia coli inactivation by solar disinfection based on the photo-generation of internal ROS and the photo-inactivation of enzymes: CAT and SOD'. Together they form a unique fingerprint.

  • Cite this