TY - JOUR
T1 - The involvement of superoxide radicals in medium pressure UV derived inactivation
AU - Gerchman, Yoram
AU - Cohen-Yaniv, Vered
AU - Betzalel, Yifaat
AU - Yagur-Kroll, Sharon
AU - Belkin, Shimshon
AU - Mamane, Hadas
N1 - Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/9/15
Y1 - 2019/9/15
N2 - Today, two types of lamp systems dominate the UV disinfection industry: low-pressure (LP) UV lamps and medium-pressure (MP) polychromatic lamps. Both lamp types have their advantages and disadvantages in microorganism inactivation, with LP lamps being cheaper, having longer life, and working at lower temperature, hence reducing fouling, and MP lamps showing better inactivation per germicidal dose for certain microorganisms. Bacterium-based biosensors were used to compare LP and MP irradiation. These biosensors were Escherichia coli bacteria carrying the lux operon genes under the control of different stress-responding promoters, where activation of the specific promoter is manifested as bioluminescence. MP irradiation, considerably more than LP irradiation, resulted in activation of the superoxide dismutase expression, indicating the formation of superoxide radicals inside the cells. Accordingly, pre-exposure (immunization) of the bacteria to an activator that produces superoxide radicals resulted in lower inactivation and increased resistance to MP irradiation, but not to LP irradiation. This study shows that the difference in germicidal efficiency may result from the production of intracellular superoxide radicals by MP irradiation, at wavelengths other than 254 nm, as emitted by LP lamps.
AB - Today, two types of lamp systems dominate the UV disinfection industry: low-pressure (LP) UV lamps and medium-pressure (MP) polychromatic lamps. Both lamp types have their advantages and disadvantages in microorganism inactivation, with LP lamps being cheaper, having longer life, and working at lower temperature, hence reducing fouling, and MP lamps showing better inactivation per germicidal dose for certain microorganisms. Bacterium-based biosensors were used to compare LP and MP irradiation. These biosensors were Escherichia coli bacteria carrying the lux operon genes under the control of different stress-responding promoters, where activation of the specific promoter is manifested as bioluminescence. MP irradiation, considerably more than LP irradiation, resulted in activation of the superoxide dismutase expression, indicating the formation of superoxide radicals inside the cells. Accordingly, pre-exposure (immunization) of the bacteria to an activator that produces superoxide radicals resulted in lower inactivation and increased resistance to MP irradiation, but not to LP irradiation. This study shows that the difference in germicidal efficiency may result from the production of intracellular superoxide radicals by MP irradiation, at wavelengths other than 254 nm, as emitted by LP lamps.
KW - Bacteria
KW - Bioreporter
KW - Mechanism
KW - Superoxide radical
KW - UV disinfection
UR - http://www.scopus.com/inward/record.url?scp=85066873949&partnerID=8YFLogxK
U2 - 10.1016/j.watres.2019.05.084
DO - 10.1016/j.watres.2019.05.084
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
C2 - 31181447
AN - SCOPUS:85066873949
SN - 0043-1354
VL - 161
SP - 119
EP - 125
JO - Water Research
JF - Water Research
ER -