INACTIVATION OF PHAGE Q-BETA BY 254NM UV-LIGHT AND TITANIUM-DIOXIDE PHOTOCATALYST

The disinfection efficacy of UV light irradiation at wavelength of 254 nm over a titanium dioxide (TiO2) suspension was compared to that of UV alone. Bacteriophage Q beta was used as a model virus for the study . Q beta in sterilized pure water and TiO2 suspension was irradiated b y a 0.4 mW/cm(2) intensity of 254nm UV light. The UV light over TiO2 w as more effective than 254nm UV alone in inactivating Q beta. 3.5-log( 10) Q beta inactivation was achieved by UV irradiation over TiO2 suspe nsion (10(3) mg/L) after 2 minutes of irradiation, while UV alone inac tivated 2-log(10). Using a MPN-PCR method, a ca. 1-log(10)-unit decrea se in Q beta RNA concentration was detected after 3 minutes of photoca talytic irradiation. The decrease was explained by damage to nucleic a cid of phage Q beta due to radical oxidation, which is generated by ph otocatalysis.