title: Impact of nanoscale zero valent iron on bacteria is growth phase dependent.
abstract: The toxic effect of nanoscale zero valent iron (nZVI) particles on bacteria from different growth phases was studied. Four bacterial strains namely Escherichia coli strains JM109 and BW25113, and Pseudomonas putida strains KT2440 and F1 were experimented. The growth curves of these strains were determined. Bacterial cells were harvested based on the predetermined time points, and exposed to nZVI. Cell viability was determined by the plate count method. Bacterial cells in lag and stationary phases showed higher resistance to nZVI for all four bacterial strains, whereas cells in exponential and decline phases were less resistant to nZVI and were rapidly inactivated when exposed to nZVI. Bacterial inactivation increased with the concentration of nZVI. Furthermore, less than 14% bacterial inactivation was observed when bacterial cells were exposed to the filtrate of nZVI suspension suggesting that the physical interaction between nZVI and cell is necessary for bacterial inactivation.
authors.affiliation: International Postgraduate Programs in Environmental Management, Graduate School Chulalongkorn University, Bangkok 10330, Thailand; Environmental and Conservation Sciences, North Dakota State University, Fargo, ND 58108, USA.
authors.forename: Krittanut
authors.initials: K
authors.lastname: Chaithawiwat
authors.affiliation: Department of Biochemistry, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Alisa
authors.initials: A
authors.lastname: Vangnai
authors.affiliation: Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, ND 58108, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: McEvoy
authors.affiliation: Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, ND 58108, USA.
authors.forename: Birgit
authors.initials: B
authors.lastname: Pruess
authors.affiliation: Medora Corporation, Dickinson, ND 58601, USA.
authors.forename: Sita
authors.initials: S
authors.lastname: Krajangpan
authors.affiliation: Department of Civil and Environmental Engineering, North Dakota State University, Fargo, ND 58108, USA. Electronic address: eakalak.khan@ndsu.edu.
authors.forename: Eakalak
authors.initials: E
authors.lastname: Khan
mesh_terms: D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D007501:Iron / Q000633:toxicity*; D053768:Metal Nanoparticles / Q000633:toxicity*; D016958:Pseudomonas putida / Q000187:drug effects* / Q000254:growth & development; D013535:Suspensions
chemical_list: D013535:Suspensions; D007501:Iron
keywords: Bacteria; Growth phase; Nanoscale zero valent iron; Toxicity