Oxidation of Fe(II) by Flavins under Anoxic Conditions

This project aims to understand the redox reaction between Fe(II) and flavins. Our study demonstrated that aqueous Fe(II) can be oxidized by the oxidized form of riboflavin and flavin mononucleotide at pH 7–9. Both the rates and extents of oxidation increased with increasing concentration of oxidized flavins and increasing solution pH. Our data are from experiments, which mainly consist of the chemical variables, were collected in the Ecohydrology lab at the University of Waterloo using the batch reaction system. All the experiments were conducted in 125 mL serum bottles at 22±1 ℃ in an anaerobic glovebox (95% N2 and 5% H2). The bottles contained Teflon-coated magnetic stir bars and were wrapped in aluminum foil to exclude light. Prior to an experiment, a solution containing 20 mM buffer and 10 mM NaCl was purged with N2 (99.998%) for at least 2 h to remove O2, then transferred to the anaerobic glovebox. Aqueous Fe2+ and uncomplexed RBF and FMN concentrations were analyzed by using a Flexstation Multimode Microplate Reader. The total concentrations of RBF and FMN were determined at 450 nm on a UV-vis spectrometer kept in the anaerobic glovebox Additional details on the project are available in Environmental Science and Technology publication titled "Oxidation of Fe(II) by flavins under anoxic conditions" (doi: 10.1021/acs.est.0c02916)