Photoreactivation and dark repair of environmental E. coli strains following 24kHz continuous ultrasound and UV-C irradiation. Academic Article uri icon


  • In this study, effects of 24kHz continuous ultrasound and UV-C on inactivation and potential repair of environmental E. coli strains were studied through a culture based method and a metabolic activity assay. Three environmental E. coli strains isolated from fecal samples of feral hog and deer and treated wastewater effluent were studied and compared with a laboratory E. coli strain (ATCC 10798). Metabolic activity of E. coli cells during the inactivation and repair period was assessed using the AlamarBlue assay. Transmission electron microscopy assays were also performed to evaluate morphological damage of bacterial cell wall. After 24h of photoreactivation period, laboratory E. coli strain (ATCC 10798) reactivated by 30% and 42% in contrast to E. coli isolate from treated wastewater effluent, which reactivated by 53% and 82% after ultrasound and UV-C treatment, respectively. Possible shearing and reduction in cell size of E. coli strains exposed to ultrasound was revealed by transmission electron micrographs. Metabolic activity of E. coli strains was greatly reduced due to morphological damage to cell membrane caused by 24kHz continuous ultrasound. Based upon experimental data and TEM micrographs, it could be concluded that ultrasound irradiation has potential in advanced water treatment and water reuse applications.

published proceedings

  • J Environ Sci Health A Tox Hazard Subst Environ Eng

author list (cited authors)

  • Kaur, J., Karthikeyan, R., & Pillai, S. D.

citation count

  • 6

complete list of authors

  • Kaur, Jasjeet||Karthikeyan, Raghupathy||Pillai, Suresh D

publication date

  • July 2016