ABSTRACT
The effects of atomic oxygen radical anion (O-) on the inactivation and morphological changes ofEscherichia coli (E. coli)on the surface of bio-indicator carrier were investigated. The O- flux was generated from a novel developed O- generator where the Oinactivation ofE. coli was sensitive to the O- intensity and the cell mortality was enhanced to more than 3-logarithm reduction with the exposure to 1.5 mA/cm2 O- flux for 120 min. Field emission scanning electron microscopy (FESEM) observations showed that O- flux destroyed cellular structures. Lipid peroxidation reaction induced by atomic oxygen radical anion for E. coli cells was also observed using product of malondialdehyde (MDA) as an index. The concentration of MDA increased to 1.2 μmol/g(dry weight) of cells when E. coli suspension (5.6×107 cfu/ml) was treated by the O- flux (1.5 μA/cm2) for 15 min. The findings revealed that the atomic oxygen radical anions, with strong oxidation power, was effective in inactivating E. coli and caused lipid peroxidation reaction at the first time,which would be potential useful to develop a novel approach for the microbial decontamination and for the study on the interactions between microorganisms and O-.