Reduction of sulfur and oxidized forms of nitrogen by bacteria of Desulfuromonas sp., isolated from Yavorivske Lake, under the influence of ferrum citrate

B M Borsukevych,G V Yavorska,O D Maslovska,O M Moroz,S O Hnatush

doi:10.15421/012009

Abstract

Technogenic reservoirs mainly contain several possible electron acceptors of anaerobic respiration, many of which are dangerous to the environment. The succession of their reduction (and thus detoxification) by sulfur reducing bacteria is not yet sufficiently studied. We investigated the influence of ferrum (III) citrate, present in the cultivation medium, on the reduction of sulfur, nitrate and nitrite ions by sulfur reducing bacteria Desulfuromonas acetoxidans IMV B-7384, Desulfuromonas sp. Yavor-5 and Desulfuromonas sp. Yavor-7, isolated from Yavorivske Lake. It was established that ferrum (III) citrate inhibits the biomass accumulation and hydrogen sulfide production by bacteria of Desulfuromonas sp. after simultaneous addition to the medium of 3.47 mM S0 and 1.74–10.41 mM ferrum (III) citrate, as compared with growth and hydrogen sulfide production by bacteria in the medium with only sulfur. In the medium with the same initial content (3.47 mM) S0 and ferrum (III) citrate bacteria produced ferrum (II) ions at concentrations 3.5–3.9 times higher than that of hydrogen sulfide. Ferrum (III) citrate inhibits the biomass accumulation, the nitrate or nitrite ions reduction and the ammonium ions production by bacteria of Desulfuromonas sp. after simultaneous addition to the medium of 3.47 mM NaNO3 or NaNO2 and 1.74–10.41 mM ferrum (III) citrate. In the medium with the same initial content (3.47 mM) NaNO3 and ferrum (III) citrate, bacteria produced ammonium ions at concentrations in 1.1 times higher than that of ferrum (II) ions. In the medium with the same initial content (3.47 mM) NaNO2 and ferrum (III) citrate, bacteria reduced 1.5–1.6 times more ferrum (III) than nitrite ions with production of ferrum (II) ions at concentrations 1.7 times higher than that of ammonium ions. The process of nitrate reduction carried out by bacteria of Desulfuromonas genus was less sensitive to the negative influence of ferrum (III) citrate, compared to the process of nitrite ions reduction. When the reduction of nitrate ions by bacteria in the presence of 1.74–10.41 mM ferrum (III) citrate decreased by 1.4–2.2 times, then the reduction of nitrite ions decreased by 1.8–3.2 times compared to their reduction in media with only NaNO3 or NaNO2, respectively. Although the reduction of ferrum (III) by cells in media with 3.47 mM S0, NaNO3 or NaNO2 and 1.74–10.41 mM ferrum (III) citrate decreased by 1.6–2.7, 1.6–2.7 and 1.1–2.2 times, respectively, compared to the reduction in medium with only ferrum (III) citrate, the investigated strains of bacteria were resistant to high concentrations of trivalent ferrum compounds and can therefore can be used in technologies of complex purification of environments polluted by heavy metal and nitrogen compounds.

Highlights

Introduction gues in natureA distinctive feature of the sulfur quarry is the presence of aquifers in the sulfate-carbonate layers of the Neogene, which containSulfidogenic bacteria of the Desulfuromonas genus in the process large amounts of hydrogen sulfide (Gaidin & Zozulia, 2009)
We investigated the influence of ferrum (III) citrate, present in the cultivation medium, on the reduction of sulfur, nitrate and nitrite ions by sulfur reducing bacteria Desulfuromonas acetoxidans IMV B-7384, Desulfuromonas sp
To study the influence of ferrum (III) citrate on the sulfur reduction by sulfur reducing bacteria, they were grown in the medium with sodium citrate, to which 3.47 mM S0 and FeC6H5O7 at different concentrations were added

Summary

Introduction

Introduction gues in natureA distinctive feature of the sulfur quarry is the presence of aquifers in the sulfate-carbonate layers of the Neogene, which containSulfidogenic bacteria of the Desulfuromonas genus in the process large amounts of hydrogen sulfide (Gaidin & Zozulia, 2009). Of anaerobic respiration can use sulfur, oxidized forms of nitrogen or the metabolic processes carried out by sulfidogenic bacteria determine heavy metals, in particular, ferrum (III) as electron acceptors. In the water of Yavorivske Lake at all depths the concentrations of compounds of sulfur (SO42– up to 1529– 1725 mg/L, H2S up to 34.0–47.2 mg/L), nitrogen (NO3– up to 2.5 mg/L) (Moroz et al, 2008; Tarabas et al, 2017) and heavy metals (Mn(II) up than 90 m was formed (Baran et al, 2003; Gudz et al, 2004; Gaidin & to 0.243 mg/L, Cd(II) up to 0.031 mg/L, Fe(II) up to 0.144 mg/L, Zozulia, 2009). In particular, New hydrogeological and hydrological conditions are formed, and a representatives of the sulfidogenic microbiota, isolated from contaminew grouping of microorganisms is created that does not have analo- nated environments, are adapted to stress factors, so they are most suita-

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