Regulatory Mechanisms in Biosystems (May 2020)
Reduction of perchlorate ions by the sulfate-reducing bacteria Desulfotomaculum sp. and Desulfovibrio desulfuricans
Abstract
The usage of microorganisms to clean the environment from xenobiotics, in particular chlorine-containing ones, is a promising method of detoxifying the contaminated environment. Sulfate-reducing bacteria Desulfovibrio desulfuricans Ya-11, isolated from Yavoriv Lake, and Desulfotomaculum AR1, isolated from the Lviv sewage treatment system, are able to grow under conditions of environmental contamination by aromatic compounds and chlorine-containing substances. Due to their high redox potential, chlorate and perchlorate ions can be ideal electron acceptors for the metabolism of microorganisms. To test the growth of the tested microorganisms under the influence of perchlorate ions, bacteria were cultured in modified Postgate C medium with ClO4–. Biomass was determined turbidimetrically, the content of sulfate ions and hydrogen sulfide – photoelectrocolorimetrically, the content of perchlorate ions – permanganatometrically. The study of the ability of sulfate-reducing bacteria Desulfotomaculum AR1 and D. desulfuricans Ya-11 to grow in a medium with perchlorate ions as electron acceptors showed the inhibitory effect of ClO4– on sulfate ion reduction by bacteria. Bacteria Desulfotomaculum AR1 and D. desulfuricans Ya-11 are able to grow in environments with aromatic hydrocarbons, in particular toluene. The possibility of the growth of sulfate-reducing bacteria in the presence of toluene as an electron donor and perchlorate ions as an electron acceptor was investigated. The efficiency of perchlorate ion utilization by sulfate-reducing bacteria Desulfotomaculum AR1 and D. desulfuricans Ya-11 was about 90 %. The effect of molybdenum on the reduction of perchlorate ions by Desulfotomaculum AR1 is shown in the paper. Immobilization of bacteria Desulfotomaculum AR1 and D. desulfuricans Ya-11 was carried out in 3% agar and on wood chips. The ability of bacteria, immobilized on these media, to purify the aqueous medium from perchlorate ions was investigated. Reduction of perchlorate ions is more efficiently performed by cells of Desulfotomaculum AR1 and D. desulfuricans Ya-11 bacteria immobilized in agar than on wood chips. Sulfate-reducing bacteria Desulfotomaculum AR1 and D. desulfuricans Ya-11 are able to use perchlorate ions as electron acceptors, purifying the polluted aquatic environment from these pollutants.
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