Mechanism of disinfection: Effect of chlorine on cell membrane functions

To elucidate the mechanism of disinfection by chlorine, its effects on some vital properties associated with cell membrane of Escherchia coli were studied. There was no significant change in Zeta potential at bactericidal doses of chlorine. Treatment with chlorine induced the leakage of macromolecules from the cells indicating the permeability changes of the membrane. Proteins and RNA were detected in the supernatant when the cells were treated with chlorine dose of 1.5 mg 1⁻¹ (100 μg Cl mg⁻¹ N). The presence of DNA was observed only at high chlorine doses. The studies on oxidative phosphorylation of cell free extract indicated the complete cessation of phosphate uptake at a dose of 0.4 mg 1⁻¹ (30 μg Cl mg⁻¹ N). There was about 70% decrease in the oxygen uptake corresponding to chlorine dose of 0.8 mg 1⁻¹.