Inactivation of Bacterial and Fungal Species During Ozonation

The present study was undertaken to evaluate the antibacterial and antifungal effect of ozone in aqueous condition by using an apparatus made by standard appliances Varanasi. The bacterial samples were collected from the hospital patients of BHU, Varanasi (U.P.) India. The fungal strains were collected from different fields of BHU. The samples were examined for isolation and identification of bacteria and fungi. The isolates of fungi and bacteria were subjected to ozone treatment at different time duration. The system was subjected to ozonation for 5, 10, 15, 20 and 25min for bacteria and 20, 40, 60, 80, 100 and 120min. for fungal spore. Escherichia coli, Pseudomonas aeruginosa, Vibrio cholerae and Salmonella typhi were killed after 15min of ozonation. Still, Klebsiella pneumoniae grew after 20min of ozonation and survived up to 25min. Among fungi Fusarium oxysporum f. sp. lini showed much susceptibility followed by Trichoderma harzianum, Aspergillus luchuchensis, A. niger, A. flavus and A. terreus. There was reduction in colony count from 40min to 120min of ozonation but all the fungi survived even after 2h of ozonation.The exposure of bacterial strainto ozone doses of 20ppm to 25ppm for 5 to 25min were sufficient for inhibition of bacterial growth. While the growth inhibition of fungi required exposure to ozone doses of 15ppm to 25ppm for 40 to 120min.The increase in the exposure time at any ozone concentration resulted in a significant reduction in fungal and bacterial growth.