(320ak) Sterilization of Pathogenic Bacteria Using Titanium Dioxide Photocatalyst

Titanium dioxide (TiO2) photocatalysts have attracted great attention as a material for photocatalytic sterilization in the food and environmental industry. This research aimed to design a new photobioreactor and its application to sterilize selected pathogenic bacteria, Salmonella choleraesuis subsp., Vibrio parahaemolyticus, Listeria monocytogenes, and Pseudomonas sp. The photocatalytic reaction was carried out with various TiO2 concentrations, ultraviolet (UV) illumination time, temperature and pH. The bactericidal effect of TiO2 under UV light irradiation on all bacterial suspension was much higher than that of without TiO2. As the concentration of TiO2 increased to 1.0 mg/ ml, bactericidal effect increased. The complete killing time of Salmonella, Vibrio and Pseudomonas was achieved after 3 hr but Listeria was more resistant. However, titanium dioxide powder could not be used satisfactorily for the sterilization of the bacteria due to its poor separation from the suspension. Therefore, in this study, chitosan bead was coated with titanium dioxide by sol-gel method, and used for sterilization. The survival ratio of Salmonella using chitosan bead coated with TiO2 was lower than that of chitosan bead.