Photoreactivation and dark repair of environmental E. coli strains following 24 kHz continuous ultrasound and UV-C irradiation. Issue 8 (2nd July 2016)

• Record Type: Journal Article
• Authors: Kaur, Jasjeet; Karthikeyan, Raghupathy; Pillai, Suresh D.
• Is Part Of: Journal of environmental science and health. Volume 51:Issue 8(2016)
• Page Start: 607
• Page End: 613
• Publication Date: 2016-07-02
• Subjects: Disinfection -- indicator organisms -- ultraviolet irradiation -- water quality; Environmental engineering -- Periodicals; Environmental sciences -- Periodicals; Ecology -- periodicals; Hazardous Substances -- periodicals; 628
• DOI: 10.1080/10934529.2016.1159860
• Languages: English
• ISSNs: 1093-4529

Abstract

ABSTRACT: In this study, effects of 24 kHz 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 24 h 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 24 kHz 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.