Inactivation of Pseudomonas aeruginosa by zinc oxide nanoparticles in aqueous solution

Introduction

Since ZnO nanoparticles (ZnO-NPs) exhibit strong antibacterial activities on a broad spectrum of bacteria the aim of this study was to evaluate the antimicrobial activity of Zno-NPs against Pseudomonas aeruginosa as a model for gram-negative bacteria.

Methods

The average size of Zno-NPs was 20 nm, as determined through scanning electron microscopy. Muller Hinton broth was used as a growing medium for Pseudomonas aeruginosa. Photocatalytic experiment was carried out in a laboratory-scale batch reactor with low pressure ultraviolet irradiation (380 nm). Different experimental parameters such as amount of Zno-NPs, contact time, inorganic and organic substances and pH on photocatalytic inactivation of Pseudomonas aeruginosa cells have been studied. An initial Pseudomonas aeruginosa concentration of 10⁸ CFU/mL was used for all experiments.

Results

Result showed that, almost all the initial Pseudomonas aeruginosa cell (10⁸ CFU/ml) was inactivated in 60 min in the presence of 2 g/l ZnO-NPs. Photocatalytic inactivation of bacteria was found to follow first order kinetics. The initial pH of the water did not play an important role on the inactivation rate within a range of 6–8 pH units. The amount of photocatalyst also plays an important role in photocatalytic inactivation rate. As the result showed increasing the photocatalyst amount provided more rapid inactivation.

Conclusion

Addition of some inorganic ions to the suspension affects the sensitivity of Pseudomonas aeruginosa and caused to retard the inactivation rates. Since the sensitivity of Pseudomonas aeruginosa to photocatalytic treatment was fairly good, it is therefore, recommended to use this nano-particle for water treatment.

Disclosure of interest

None declared.