title: Inactivation of bacteriophage MS2 with potassium ferrate(VI).
abstract: Ferrate [Fe(VI); FeO(4)(2-)] is an emerging oxidizing agent capable of controlling chemical and microbial water contaminants. Here, inactivation of MS2 coliphage by Fe(VI) was examined. The inactivation kinetics observed in individual batch experiments was well described by a Chick-Watson model with first-order dependences on disinfectant and infective phage concentrations. The inactivation rate constant k(i) at a Fe(VI) dose of 1.23 mgFe/L (pH 7.0, 25 °C) was 2.27(±0.05) L/(mgFe × min), corresponding to 99.99% inactivation at a Ct of ~4 (mgFe × min)/L. Measured k(i) values were found to increase with increasing applied Fe(VI) dose (0.56-2.24 mgFe/L), increasing temperature (5-30 °C), and decreasing pH conditions (pH 6-11). The Fe(VI) dose effect suggested that an unidentified Fe byproduct also contributed to inactivation. Temperature dependence was characterized by an activation energy of 39(±6) kJ mol(-1), and k(i) increased >50-fold when pH decreased from 11 to 6. The pH effect was quantitatively described by parallel reactions with HFeO(4)(-) and FeO(4)(2-). Mass spectrometry and qRT-PCR analyses demonstrated that both capsid protein and genome damage increased with the extent of inactivation, suggesting that both may contribute to phage inactivation. Capsid protein damage, localized in the two regions containing oxidant-sensitive cysteine residues, and protein cleavage in one of the two regions may facilitate genome damage by increasing Fe(VI) access to the interior of the virion.
authors.affiliation: Department of Civil and Environmental Engineering and Center of Advanced Materials for the Purification of Water with Systems, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Lanhua
authors.initials: L
authors.lastname: Hu
authors.forename: Martin A
authors.initials: MA
authors.lastname: Page
authors.forename: Therese
authors.initials: T
authors.lastname: Sigstam
authors.forename: Tamar
authors.initials: T
authors.lastname: Kohn
authors.forename: Benito J
authors.initials: BJ
authors.lastname: Mariñas
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Strathmann
mesh_terms: D036022:Capsid Proteins / Q000378:metabolism; D004202:Disinfectants / Q000494:pharmacology*; D004926:Escherichia coli / Q000821:virology; D016679:Genome, Viral / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D058085:Iron Compounds / Q000494:pharmacology*; D007700:Kinetics; D017909:Levivirus / Q000187:drug effects* / Q000502:physiology; D008954:Models, Biological; D017680:Potassium Compounds / Q000494:pharmacology*; D013696:Temperature; D038301:Virus Inactivation / Q000187:drug effects; D014873:Water Pollutants; D018508:Water Purification / Q000379:methods*
chemical_list: D036022:Capsid Proteins; D004202:Disinfectants; D058085:Iron Compounds; D017680:Potassium Compounds; D014873:Water Pollutants; C044384:potassium ferrate