Inhibition mechanism of Microcystis aeruginosa under UV-C irradiation

Abstract

The inhibition of Microcystis aeruginosa in water with UV-C irradiation was investigated. Results revealed that 84% of M. aeruginosa were removed on the 5th day after UV-C irradiation at a dose of 2,117 mJ/cm². The SEM images of irradiated M. aeruginosa cells showed evidence of injury. However, the presence of CH₃OH, thiourea, and decreased the UV-C irradiation efficiency. Acidic conditions were more conducive to M. aeruginosa removal than neutral or alkaline conditions. H₂O₂ in the mM level was added into the M. aeruginosa solution to investigate the removal efficiency, and the results indicated that 94% of M. aeruginosa were removed. The phycocyanin photosynthetic pigment content in M. aeruginosa cells decreased with the increase of UV-C irradiation dose. Low UV-C irradiation doses enhanced the activity of superoxide dismutase (SOD) in the M. aeruginosa cells, whereas the SOD activity decreased with high doses.

Keywords:

• Microcystis aeruginosa
• UV-C irradiation
• Additive
• Superoxide dismutase
• Phycocyanin

Acknowledgments

This study was supported by the Major Science and Technology Program for Water Pollution Control and Treatment (Nos. 2012ZX07102-004 and 2012ZX07103-004).