Electron Donor Utilization and Secondary Mineral Formation during the Bioreduction of Lepidocrocite by Shewanella putrefaciens CN32

Abstract

The bioreduction of Fe(III) oxides by dissimilatory iron reducing bacteria (DIRB) may result in the production of a suite of Fe(II)-bearing secondary minerals, including magnetite, siderite, vivianite, green rusts, and chukanovite; the formation of specific phases controlled by the interaction of various physiological and geochemical factors. In an effort to better understand the effects of individual electron donors on the formation of specific Fe(II)-bearing secondary minerals, we examined the effects of a series of potential electron donors on the bioreduction of lepidocrocite (γ-FeOOH) by Shewanella putrefaciens CN32. Biomineralization products were identified by X-ray diffraction, Mössbauer spectroscopy, and scanning electron microscopy. Acetate, citrate, ethanol, glucose, glutamate, glycerol, malate, and succinate were not effectively utilized for the bioreduction of lepidocrocite by S. putrefaciens CN32; however, substantial Fe(II) production was observed when formate, lactate, H2, pyruvate, serine, or N acetylglucosamine (NAG) was provided as an electron donor. Carbonate or sulfate green rust was the dominant Fe(II)-bearing secondary mineral when formate, H2, lactate, or NAG was provided, however, siderite formed with pyruvate or serine. Geochemical modeling indicated that pH and carbonate concentration are the key factors determining the prevalence of carbonate green rust verses siderite.

Effects of Fe(III) Oxide Mineralogy and Phosphate on Fe(II) Secondary Mineral Formation during Microbial Iron Reduction

“…In addition to the presence/concentration of phosphate, other factors have been proposed to contribute to the formation of green rusts during Fe(III) oxide bioreduction, including the presence of other oxyanions (arsenate, silicate, molybdate, tungstate, etc.) [31,41]; the presence and nature of dissolved organic carbon (including humic substances and microbially produced extracellular polymeric materials) [31,33,38]; the species and population size of IRB [31][32][33]; the type and concentration of the electron donor [18,36,37]; the rate and extent of Fe(II) production [17,19,125]; the presence of electron shuttles [17]; the sorption of Fe(II) to the parent Fe(III) oxide [25]; the extent of aggregation of Fe(III) oxide particles [27]; Fe(III) oxide mineralogy (this study). Despite over 20 years of investigation, a definitive and comprehensive understanding of the key factor(s) and mechanisms of green rust formation during microbial Fe(III) oxide reduction remains elusive.…”

“…Many factors have been identified as contributing to the formation of specific Fe(II)bearing secondary minerals during the microbial reduction of Fe(III) oxides, including Fe(III) oxide mineralogy [19,25,26]; Fe(III) oxide particle aggregation [27]; the presence of electron shuttles [17]; the rate and extent of Fe(II) production [17,19,[28][29][30]; the extent of Fe(II) sorption on the parent Fe(III) oxide [25]; the species of IRB and the number of cells present [31][32][33]; the concentration and type of electron donor [34][35][36][37]; the type of organic matter present (including humic substances and microbially-produced extracellular polymeric materials) [31,33,38]; and the presence of phosphate and other oxyanions (silicate, molybdate, arsenate, etc.) [17,31,[39][40][41].…”

Reduction of Sb(V) by coupled biotic-abiotic processes under sulfidogenic conditions

“…The reduction of ferrihydrite was assessed by measuring the Fe(II) in the suspensions by acid extraction and analysis by the ferrozine method (Stookey 1970) using HEPES-buffered ferrozine reagent (Sørensen 1982) as described by O'Loughlin et al (2019). Sulfate reduction was monitored by measuring sulfate concentration using the method of Kolmert et al (2000), scaled for 0.5 mL of sample.…”

The Role of Microorganisms in the Formation, Dissolution, and Transformation of Secondary Minerals in Mine Rock and Drainage: A Review

“…Some microorganisms decrease iron concentration in solution through siderophore production, which forms complexes with iron in solution [114]. The bioreduction of Fe(III) oxides or dissolved Fe(III) by iron-reducing bacteria may produce Fe(II)-containing secondary minerals, such as magnetite, siderite, vivianite, green rusts, and chukanovite, and the actual Fe(II)-containing secondary mineral produced is influenced by the type of electron donors present [139,140].…”