Potential and Risk of the Visible Light Assisted Photocatalytical Treatment of PRD1 and T4 Bacteriophage Mixtures

In current study UV light and visible light activated photocatalytic inactivation treatment was applied to the less commonly studied subjects, namely bacteriophages PRD1, T4 and their mixture. By using UV light irradiation and high efficiency P25 TiO2 photocatalyst powders it was demonstrated that individually and in mixture PRD1 bacteriophage is particularly vulnerable to the photocatalytic inactivation and in just approximately 20 min its infectivity is reduced by 100 %. As for the T4 bacteriophage, it has been reported that under UV irradiation T4 triggers self-repair and replication mechanisms therefore under same photocatalytic inactivation conditions infectivity reduction reaches just 60 %. Surprisingly, by studying visible light photocatalytic treatment efficiency of PRD1 and T4 bacteriophage mixture we identified that T4 bacteriophage potentially triggers the same self-repair and replication mechanism as it does under UV light. Moreover, by using two different types of visible light activated photocatalysts we determined that when efficiency of the used photocatalyst is too small the overall infectivity of the T4 bacteriophage can significantly surpass the corresponding property of the untreated control group.