Reductive precipitation of sulfate and soluble Fe(III) by Desulfovibrio vulgaris: Electron donor regulates intracellular electron flow and nano-FeS crystallization.

Title Reductive precipitation of sulfate and soluble Fe(III) by Desulfovibrio vulgaris: Electron donor regulates intracellular electron flow and nano-FeS crystallization.
Authors C. Zhou; Y. Zhou; B.E. Rittmann
Journal Water Res
DOI 10.1016/j.watres.2017.04.044
Abstract

Fully understanding the metabolism of SRB provides fundamental guidelines for allowing the microorganisms to provide more beneficial services in water treatment and resource recovery. The electron-transfer pathway of sulfate respiration by Desulfovibrio vulgaris is well studied, but still partly unresolved. Here we provide deeper insight by comprehensively monitoring metabolite changes during D. vulgaris metabolism with two electron donors, lactate and pyruvate, in presence or absence of citrate-chelated soluble Fe(III) as an additional competing electron acceptor. H2 was produced from lactate oxidation to pyruvate, but pyruvate oxidation produced mostly formate. Accumulation of lactate-originated H2 during lag phases inhibited pyruvate transformation to acetate. Sulfate reduction was initiated by lactate-originated H2, but MQ-mediated e(-) flow initiated sulfate reduction without delay when pyruvate was the donor. When H2-induced electron flow gave priority to Fe(III) reduction over sulfate reduction, the long lag phase before sulfate reduction shortened the time for iron-sulfide crystallite growth and led to smaller mackinawite (Fe1+xS) nanocrystallites. Synthesizing all the results, we propose that electron flow from lactate or pyruvate towards SO4(2-) reduction to H2S are through at least three routes that are regulated by the e(-) donor (lactate or pyruvate) and the presence or absence of another e(-) acceptor (Fe(III) here). These routes are not competing, but complementary: e.g., H2 or formate production and oxidation were necessary for sulfite and disulfide/trisulfide reduction to sulfide. Our study suggests that the e(-) donor provides a practical tool to regulate and optimize SRB-predominant bioremediation systems.

Citation C. Zhou; Y. Zhou; B.E. Rittmann.Reductive precipitation of sulfate and soluble Fe(III) by Desulfovibrio vulgaris: Electron donor regulates intracellular electron flow and nano-FeS crystallization.. Water Res. 2017;119:91101. doi:10.1016/j.watres.2017.04.044

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Sulfur

See more Sulfur products. Sulfur (or Sulphur) (atomic symbol: S, atomic number: 16) is a Block P, Group 16, Period 3 element with an atomic radius of 32.066. Sulfur Bohr ModelThe number of electrons in each of Sulfur's shells is 2, 8, 6 and its electron configuration is [Ne] 3s2 3p4. In its elemental form, sulfur has a light yellow appearance. The sulfur atom has a covalent radius of 105 pm and a Van der Waals radius of 180 pm. In nature, sulfur can be found in hot springs, meteorites, volcanoes, and as galena, gypsum, and epsom salts. Sulfur has been known since ancient times but was not accepted as an element until 1777, when Antoine Lavoisier helped to convince the scientific community that it was an element and not a compound.

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