Daños bioquímicos en Escherichia coli y Salmonella enterica var. thyphimurium aplicando bajas concentraciones de ozono en medio acuoso.

Ozone efficiency in the water treatment systems is widely published in national and international papers. The criteria design of the treatment plants have changed over the years with increasing knowledge about the mechanism through which ozone reacts with chemical and microbiological pollutants. It recognizes the existence of a relationship between morphological and physiological characteristics of microorganisms and their resistance to ozone. However, there are few studies reported about the mechanisms by which ozone inactivates microorganisms in aqueous media. The aim of this study was to evaluate the effect of ozone on cytoplasmic membrane and enzymes related to oxidative balance on two microorganisms: Escherichia coli ATCC 25922 and Salmonella enterica var. Thyphimurium ATCC 12 048. From a kinetic study was determined, the variation of the efflux of potassium, changes in SH groups and the action exerted by ozone on the enzymes catalase and superoxide dismutase. The results showed an involvement of SH groups present, mainly, in protein and the potassium efflux outside microbial cells, demonstrating that these compound are among the first targets of ozone on microorganisms. An increased activity of the catalase enzyme and a decreased activity of superoxide dismutase enzyme were observed. The decrease in the relationship between these two enzymes suggests that the antioxidant systems of microorganisms are not able to counteract the damage caused by ozone. [ABSTRACT FROM AUTHOR]