OP-II-3

PP-II-34PHOTOCATALYTIC DISINFECTION OF LEGIONELLAPNEUMOPHILA ON Ag-DOPED TITANIA THIN FILMObuchi E. a , Yanagi K. a , Kato K. a , Kuroiwa A. b and Nakano K. aa Department of Chemical Engineering, Fukuoka University,8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, JAPAN, eobuchi@fukuoka-u.ac.jpb Department of Microbiology and Immunology, Fukuoka University School ofMedicine, 7-45-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, JAPANAbstractWe investigated the photocatalytic disinfection of Legionella pneumophila(L. pneumophila) in water using titania thin film and Ag-doped titania thin film forcomparison of their activities. Both photocatalytic thin films could disinfect L. pneumophilaunder UV irradiation, Ag-doped titania thin film have higher activity than un-doped one.Furthermore, Ag-doped titania thin film could slightly disinfect L. pneumophila without UVirradiation. As it has bactericidal effect even in the dark, it is possible to make up for aweak point of photocatalytic disinfection. We also observed scanning electron microscopy(SEM) Image of L. pneumophila after the photocatalytic disinfection. The cell wall of L.pneumophila was destroyed (dissolved) by Ag-titania thin film, and endotoxin, which is akind of toxic contents in bacteria could decompose endotoxin below the detection limit.INTRODUCTIONLegionella pneumophila (L. pneumophila) is well-known as a cause of seriouspneumonia. In Japan, it is often detected in the facilities related to water such ashot-spring resorts and the cooling towers. In general, water is disinfected usingchlorine. However, as bacteria have the tolerance against chlorine, they might becomethe cause of infection. Therefore, sterilization using photocatalyst attracts attention asa new sterilization method. In our previous paper [1], we have reported about newmethod to prepare the transparent titania thin film and it has the photocatalytic activityagainst organic compounds such as nitrophenol under UV irradiation. In this work, weinvestigated the photocatalytic disinfection of L. pneumophila in water using bothtitania thin film and Ag-doped titania thin film for comparison of their activity.EXPERIMENTALAmorphous titania powder obtained as reported previously [1] was dissolved inhydrogen peroxide solution (30%, Wako Chemicals, Japan). When Ag-doped titaniathin film prepared, silver acetate aqueous solution is added at the same time.Pre-cleaned quartz glass tube (id 10mm x od 12mm x length 270mm) was coated394