• myGriffith
    • Staff portal
    • Contact Us⌄
      • Future student enquiries 1800 677 728
      • Current student enquiries 1800 154 055
      • International enquiries +61 7 3735 6425
      • General enquiries 07 3735 7111
      • Online enquiries
      • Staff phonebook
    View Item 
    •   Home
    • Griffith Research Online
    • Journal articles
    • View Item
    • Home
    • Griffith Research Online
    • Journal articles
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

  • All of Griffith Research Online
    • Communities & Collections
    • Authors
    • By Issue Date
    • Titles
  • This Collection
    • Authors
    • By Issue Date
    • Titles
  • Statistics

  • Most Popular Items
  • Statistics by Country
  • Most Popular Authors
  • Support

  • Contact us
  • FAQs
  • Admin login

  • Login
  • Unveiling the photoelectrocatalytic inactivation mechanism of Escherichia coli: Convincing evidence from responses of parent and anti-oxidation single gene knockout mutants

    Author(s)
    Sun, Hongwei
    Li, Guiying
    An, Taicheng
    Zhao, Huijun
    Wong, Po Keung
    Griffith University Author(s)
    Zhao, Huijun
    Year published
    2016
    Metadata
    Show full item record
    Abstract
    This study investigated photoelectrocatalytic (PEC) inactivation mechanism of bacteria using parental Escherichia coli (E. coli) BW25113 and its isogenic mutants deficient in catalase HPI (katG−, JW3914-1) and Mn-SOD (sodA−, JW3879-1). BW25113 in the mid-log phase was less susceptible to PEC inactivation than those in early-log and stationary phases, consistent with the peak activities of catalase and superoxide dismutase (SOD) at mid-log phase (30.6 and 13.0 Unit/ml/OD600). For different strains all in mid-log phase, PEC inactivation efficiency followed the order katG− > sodA− > BW25113, with the duration of 60, 60 and 90 ...
    View more >
    This study investigated photoelectrocatalytic (PEC) inactivation mechanism of bacteria using parental Escherichia coli (E. coli) BW25113 and its isogenic mutants deficient in catalase HPI (katG−, JW3914-1) and Mn-SOD (sodA−, JW3879-1). BW25113 in the mid-log phase was less susceptible to PEC inactivation than those in early-log and stationary phases, consistent with the peak activities of catalase and superoxide dismutase (SOD) at mid-log phase (30.6 and 13.0 Unit/ml/OD600). For different strains all in mid-log phase, PEC inactivation efficiency followed the order katG− > sodA− > BW25113, with the duration of 60, 60 and 90 min for complete inactivation of ∼2 × 107 CFU mL−1 bacteria, respectively. Correspondingly, catalase and SOD levels of BW25113 were also higher than the mutants by 5.9 and 11.7 Unit/mL/OD600, respectively. Reactive oxygen species (ROSs) concentrations in PEC systems revealed that the inactivation performance coincided with H2O2 levels, rather than OH. Moreover, pre-incubation with H2O2 elevated catalase activities and PEC inactivation resistance of BW25113 were positively correlated. The above results indicated that H2O2 was the dominant PEC generated bactericide, and anti-oxidative enzymes especially catalase contributed greatly to the bacterial PEC resistance capacity. Further tests revealed that PEC treatment raised the intracellular ROSs concentration by more than 3 times, due to the permeated H2O2 and its intracellular derivative, OH. However, oxidative stress response of E. coli, such as increased catalase or SOD were not observed, perhaps because the ROSs overwhelmed the bacterial protective capacity. The accumulated ROSs subsequently caused oxidative damages to E. coli cells, including membrane damage, K+ leakage, and protein oxidation. Compared with BW25113, the mutants experienced damages earlier and at higher levels, confirming the essential roles of catalase and SOD in the bacterial PEC resistance.
    View less >
    Journal Title
    Water Research
    Volume
    88
    DOI
    https://doi.org/10.1016/j.watres.2015.10.003
    Subject
    Environmental management not elsewhere classified
    Publication URI
    http://hdl.handle.net/10072/142672
    Collection
    • Journal articles

    Footer

    Disclaimer

    • Privacy policy
    • Copyright matters
    • CRICOS Provider - 00233E
    • TEQSA: PRV12076

    Tagline

    • Gold Coast
    • Logan
    • Brisbane - Queensland, Australia
    First Peoples of Australia
    • Aboriginal
    • Torres Strait Islander