Reactivity of Dissolved Mn(III) Complexes and Mn(IV) Species with Reductants: Mn Redox Chemistry Without a Dissolution Step?

Inter-relationships of MnO2 precipitation, siderophore–Mn(III) complex formation, siderophore degradation, and iron limitation in Mn(II)-oxidizing bacterial cultures

“…Since PVD-producing pseudomonads are ubiquitous and prevalent bacteria in many aqueous and terrestrial ecosystems, PVD-Mn (III) and similar Mn (III) complexes of other siderophores or ligands may be an important environmental source of soluble Mn (III) , a strong redox reagent (Faulkner et al, 1994;Sunda and Kieber, 1994;Klewicki and Morgan, 1998;Gold et al, 2000;Schlosser and Hofer, 2002) that can oxidize recalcitrant organic compounds and is likely to affect the global redox cycling of Mn, pollutants, and other elements (including C, N, S, U, and Cr) that react with oxidized Mn . With a few exceptions (Kostka et al, 1995;Klewicki and Morgan, 1998;Luther et al, 1998), soluble Mn (III) has heretofore usually been considered too unstable to be significant in nature, an idea that is brought into question by the recent report of stable ligand-Mn (III) at up to 5 lM in the Black Sea and Chesapeake Bay (Trouwborst et al, 2006) and by data presented in this paper. Our results apply to both rapid and slow growth at pH 7.1-7.5 in commonly-used laboratory media with 100 lM MnCl 2 and 0-2 lM FeSO 4 .…”

“…doi:10. /j.gca.2007 at low pH, it can be stabilized by ligands including oxalate (Stone, 1987;Xyla et al, 1992), citrate (Klewicki and Morgan, 1998;Luther et al, 1998), pyrophosphate (Kostka et al, 1995;Klewicki and Morgan, 1998;Webb et al, 2005), and siderophores (Faulkner et al, 1994;Parker et al, 2004;Duckworth and Sposito, 2005a). Mn (III) complexes with siderophores such as pyoverdine (PVD) and desferrioxamine B (DFOB) have exceedingly large stability constants (K); log K (I = 0) is 47.5, 44.6, 29.9, or 32.0, respectively, for MnHPVD MnB1 , FeHPVD MnB1 , MnHDFOB + , or FeHDFOB + Duckworth and Sposito, 2005a).…”

Dissimilatory Fe(III) and Mn(IV) Reduction by Shewanella putrefaciens Requires ferE , a Homolog of the pulE ( gspE ) Type II Protein Secretion Gene

“…Anaerobic growth experiments were carried out in 13-ml Hungate tubes (Bellco Glass, Inc.) filled with 10 of ml SM and sealed with black butyl rubber stoppers under an N 2 atmosphere. Filtersterilized terminal electron acceptor stocks were added at the following final concentration (terminal electron acceptor synthesis is described in reference 11, except where indicated): NO 3 Ϫ , 15 mM; NO 2 Ϫ , 3 mM; Fe(III) citrate, 50 mM; amorphous Fe(III) oxide, 100 mM; Mn(IV), 10 mM as colloidal MnO 2 (27,41), TMAO, 25 mM; SO 3 2Ϫ , 10 mM; S 2 O 3 2Ϫ , 10 mM; fumarate, 5 mM; Se(IV), 2 mM (53); and U(VI), 2 mM as uranyl carbonate (57). When required, other antibiotics were added at the following final concentrations: chloramphenicol, 25 g/ml; gentamicin, 25 g/ml; ampicillin, 50 g/ml; and streptomycin, 50 g/ml.…”

Reaction of MnIII,IV (hydr)oxides with oxalic acid, glyoxylic acid, phosphonoformic acid, and structurally-related organic compounds

“…Klewicki and Morgan (1999) used UV-visible spectrophotometry to prove that dissolved Mn II and Mn III are both generated when citric acid is reacted with a mixed (hydr)oxide with an average Mn oxidation state close to +3.0. In addition, Luther et al (1999) employed UV-visible spectrophotometry to examine the reaction of colloidal MnO 2 with oxalic acid.…”