Factors Capable of Modifying the Response of Pseudomonas aeruginosa to the Inactivation Induced by Heterogeneous Photocatalysis

Abstract

Abstract The heterogeneous photocatalysis (HP) procedure has been demonstrated to be an interesting method for disinfecting water. It is effective for inactivating Pseudomonas aeruginosa, but its effectiveness may be reduced due to the action of several factors which are able to affect bacterial radio-sensitivity. The results reported here show the influence of nutritional stress and pre-exposure to sub-lethal UVA doses on the efficiency of the inactivation of P. aeruginosa by HP. Both previous exposures to low UVA fluencies and nutrient deprivation induce bacterial resistance to this process, in concordance with previous observations about the lethal effect of direct UVA irradiation. Starvation plus pre-irradiation did not have synergistic or antagonist effects. Kinetic parameters are presented for all three cases. These factors should be taken into account in the design of a water treatment process.