Effect of pH and Importance of Ozone initiated Radical Reactions In Inactivating Bacillus subtilis Spore |
| |
Authors: | Min Cho Hyenmi Chung Jeyong Yoon |
| |
Affiliation: | 1. School of Chemical Engineering, College of Engineering , Seoul National University , an 56–1, Shilimdong, Gwanak-gu, Seoul, 151-742, South Korea Fax: E-mail: jeyong@snu.ac.kr;2. Water Microbiology Division , National Institute of Environmental Research , Kyungseo-Dong, Seo-Ku, Inchon, 404-170, Korea |
| |
Abstract: | The effect of pH on the inactivation of Bacillus subtilis spores with ozone in a batch reactor was examined in association with the role of OH radicals. The exact effect OH radicals have on ozone inactivation of microorganism is not well understood, although a direct reaction of molecular ozone has sometimes been emphasized. This study reports a novel observation that the presence of OH radicals plays a significant role in microbial inactivation. Considering the dependence of the ozone decay rate on pH, the observed C¯ T values for achieving a 2 log inactivation using the modified Chick-Watson model was 40 % lower at pH 8.2 compared to that at pH 5.6. In the presence of OH radical scavengers (tert-butanol), the observed change of C¯ T with pH was within 10%. This difference could be explained by the significant role of OH radicals. |
| |
Keywords: | Ozone CT Concept Bacillus subtilis Hydroxyl Radical |
|
|