Premium
New water disinfection system using UVA light‐emitting diodes
Author(s) -
Hamamoto A.,
Mori M.,
Takahashi A.,
Nakano M.,
Wakikawa N.,
Akutagawa M.,
Ikehara T.,
Nakaya Y.,
Kinouchi Y.
Publication year - 2007
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2007.03464.x
Subject(s) - vibrio parahaemolyticus , escherichia coli , bacteria , chemistry , microbiology and biotechnology , hydrogen peroxide , catalase , hydroxyl radical , staphylococcus aureus , food science , radical , biochemistry , biology , enzyme , genetics , gene
Aim: To evaluate the ability of high‐energy ultraviolet A (UVA) light‐emitting diode (LED) to inactivate bacteria in water and investigate the inactivating mechanism of UVA irradiation. Methods and Results: We developed a new disinfection device equipped with high‐energy UVA‐LED. Inactivation of bacteria was determined by colony‐forming assay. Vibrio parahaemolyticus, enteropathogenic Escherichia coli , Staphylococcus aureus and Escherichia coli DH5α were reduced by greater than 5‐log 10 stages within 75 min at 315 J cm −2 of UVA. Salmonella enteritidis was reduced greater than 4‐log 10 stages within 160 min at 672 J cm −2 of UVA. The formation of 8‐hydroxy‐2′‐deoxyguanosine in UVA‐LED irradiated bacteria was 2·6‐fold higher than that of UVC‐irradiated bacteria at the same inactivation level. Addition of mannitol, a scavenger of hydroxyl radicals (OH ˙ ), or catalase, an enzyme scavenging hydrogen peroxide (H 2 O 2 ) to bacterial suspensions significantly suppressed disinfection effect of UVA‐LED. Conclusion: This disinfection system has enough ability to inactivate bacteria and OH ˙ and H 2 O 2 participates in the disinfection mechanism of UVA irradiation. Significance and Impact of the Study: We newly developed UVA irradiation system and found that UVA alone was able to disinfect the water efficiently. This will become a useful disinfection system.