title: Exposure of Microcystis aeruginosa to Hydrogen Peroxide under Light: Kinetic Modeling of Cell Rupture and Simultaneous Microcystin Degradation.
abstract: The effect of hydrogen peroxide on the cell integrity of a cyanobacterium, Microcystis aeruginosa, and on the release and degradation of microcystins (MCs) under simulated sunlight was investigated. The cyanobacterium was exposed to H2O2 in the range of 0-60 mg·L(-1) for 3.5 h. Production of OH radical in the solution was estimated by a chemical probe method. More than 99% (2 log) of the M. aeruginosa cells were ruptured or damaged by 3 h for all the treatments. Loss of cell integrity over time revealed two distinct phases. Cells retained their integrity during the initial lag phase and rapidly ruptured following first-order reaction afterward. A linear relationship was found between the duration of the lag phase and the steady-state concentration of OH radical. Release of MCs was closely correlated with the loss of cell integrity. Sequential reaction models were developed to simulate the release and degradation of MCs. These models were able to quantitatively describe the kinetics of all reactions under different H2O2 doses and extended exposure time. In particular, the models successfully predicted the concentration change of MCs using independently measured parameters. These models provide a simple and quantitative means to estimate the interaction of oxidants and cells and the consequent release of metabolites during oxidation treatment of cyanobacterium-laden waters.
authors.affiliation: †College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Xiangchen
authors.initials: X
authors.lastname: Huo
authors.affiliation: ‡Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
authors.forename: De-Wei
authors.initials: DW
authors.lastname: Chang
authors.affiliation: ‡Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
authors.forename: Jing-Hua
authors.initials: JH
authors.lastname: Tseng
authors.affiliation: §Australian Water Quality Centre, South Australian Water Corporation, Adelaide, South Australia 5000, Australia.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Burch
authors.affiliation: ‡Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
authors.forename: Tsair-Fuh
authors.initials: TF
authors.lastname: Lin
mesh_terms: D005110:Extracellular Space / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000737:chemistry; D007700:Kinetics; D008027:Light; D052998:Microcystins / Q000378:metabolism*; D046931:Microcystis / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D008962:Models, Theoretical; D016877:Oxidants / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects; D014867:Water / Q000378:metabolism
chemical_list: D052998:Microcystins; D016877:Oxidants; D014867:Water; D017665:Hydroxyl Radical; C078588:microcystin; D006861:Hydrogen Peroxide