Inactivation of bacteriophages by high levels of dissolved CO2

We developed a system with high levels of dissolved CO2 for water disinfection. Bacteriophages MS2, Q beta and Phi X174 were selected as the inactivation targets. A relatively mild inactivation effect was observed on MS2 and Q beta at different initial concentrations of dissolved CO2 at 0.3 MPa in 20-30 min When the pressure was increased to 0.6 MPa, the inactivation of MS2 and Q beta was differentially improved. However, this system was less effective for the inactivation of Phi X174. The capsid surface property is a probable reason for the low inactivation of Phi X174. The pH was not a key factor in the inactivation of bacteriophages; moreover, the results obtained using alternative gases (pressurized air and O-2) indicated that only CO2 inactivated these bacteriophages. A comparison between the results of real time polymerase chain reaction (RT-PCR) and plaque assay showed that some RNA moved out from the capsid after treatment. Capsid damage by CO2 expansion was the likely mechanism of inactivation with our method.