Photocatalytic bactericidal effect of TiO2 film on fish pathogens

In this research, fish bacteria pathogens, Streptococcus iniae and Edwardsiella tarda, are deposited on TiO2 film and radiated with 500 μW/cm2 of ultraviolet A (UV-A, 360 nm). The bacteria viability is estimated using 2, 3, 5-triphenyl tetrazolium chloride (TTC) and inhibition efficiency calculated. The results show that bacteria inhibition efficiency in UV-A radiated TiO2 film groups is significantly higher than that of UV-A radiated only groups. Regardless of fish pathogen species, inhibition efficiency of higher than 96% is found in the TiO2 coated experimental groups that are exposed in 90 min of UV-A radiation. These results suggest that combined use of UV-A and TiO2 can enhance bactericidal effects on fish pathogens in fish farm.