Мета: виділити сульфатвідновлювальні бактерії з системи очищення стічних вод міста Львова, дослідити морфологічні та фізіологічні властивості виділених мікроорганізмів. Методи. Об'єктом дослідження був штам сульфатвідновлювальних бактерій, виділений з системи очищення побутових та промислових стічних вод міста Львова. Проби води та мулу відбирали з первинного, вторинного відстійників і активного мулу системи очищення стічних вод міста Львова методом Столбунова-Рябова. Бактерії виділеного штаму культивували на селективному середовищі. Ідентифікацію виділеного штаму мікроорганізмів проводили за морфофізіологічними ознаками згідно визначника Берджі. Морфологію досліджуваної культури вивчали електронномікроскопічно. Для визначення наявності спор в клітинах їх забарвлювали за методом Пєшкова. Вміст сульфат-йону та гідроген сульфіду у культуральній рідині визначали фотометрично. Результати. Із активного мулу аеротенку системи очисних споруд міста Львова виділено штам спороутворювальних сульфатвідновлювальних бактерій, який також за відсутності сульфат-йону може використовувати елементну сірку як кінцевий акцептор електронів. За наявності сульфат-йону бактерії використовують лактат та ацетат як джерела карбону. Мікроорганізми мають форму коротких паличок, за Грамом забарвлюються негативно. Виділений штам бактерій належить до нейтрофільних, мезофільних мікроорганізмів. За морфологічними і фізіологічними властивостями виділений штам ідентифікований як Desulfotomaculum AR1. Висновки. Сульфатвідновлювальні бактерії Desulfotomaculum AR1, виділені з мулу аеротенку системи очищення стічних вод м. Львова нагромаджують до 18 мМ гідроген сульфіду за наявності у середовищі лактату чи ацетату як джерела карбону. Крім сульфат-йонів бактерії відновлюють елементну сірку, використовуючи її як кінцевий акцептор електронів.

As a result of human activity aromatic hydrocarbons enter the environment in large quantities, contaminating it. Dropping of insufficiently treated wastewater drains considerably decrease the quality of water. Quite effective biological methods of purification of contaminated environment are the usage of microorganisms. Prospective microorganisms for sewage treatment are sulfate-reducing bacteria. The purpose of the work was to investigate the ability of sulfate-reducing bacteria to use xylene and toluene as a source of carbon under different cultivation conditions.  The study objects were sulfate-reducing bacteria Desulfotomaculum AR1 and Desulfovibrio desulfuricans Ya-11. The biomass of bacteria was determined turbidimetrically, the content of sulfate ion and hydrogen sulfide – photometrically in the culture fluid. The content of fumarate was determined by the method of high-performance liquid chromatography. The ability of Desulfotomaculum AR1 and D. desulfuricans Ya-11 bacteria to use toluene and xylene as the sole source of carbon and energy has been established. In the toluene environment, a better growth of bacteria was observed. A comparison was made between the efficiency of the reduction of sulfate ions and the growth of bacteria in the control medium and the medium with aromatic compounds. The efficiency of sulfate ions reduction was sufficiently high in the control medium, whereas in the toluene/xylene media the efficiency of sulfate utilization and hydrogen sulfide accumulation was lower compared to the control parameters. The growth of Desulfotomaculum AR1 and D. desulfuricans Ya-11 sulfate-reducing bacteria was investigated in xylene and toluene media in the presence/absence of fumarate. According to the results of the studies, the best growth of the tested bacteria was observed in the medium with aromatic compounds in the presence of fumarate and sulfate ion. Efficiency of use of fumarate in the medium with toluene with bacteria Desulfotomaculum AR1 was more than 90 %. Fumarate can be used by sulfate-reducing bacteria as a source of carbon, donor and acceptor of electrons. Fumarate is most likely to inhibit sulfate reduction in Desulfotomaculum AR1 and D. desulfuricans Ya-11 bacteria, as indicated by studies showing that sulfate reduction efficiency in lactate, fumarate, and sulfate ion media was half that of control. Sulfate-reducing bacteria are capable to anaerobically degrade aromatic hydrocarbons in the presence of sulfate ions as terminal electron acceptors. The ability of sulfate-reducing bacteria Desulfotomaculum AR1 and D. desulfuricans Ya-11 to use the aromatics of the BTEХ – toluene, xylene and sulfate-ions, makes them promising at the biological purification step of contaminated wastewater from these pollutants.

ecological trophic groups. At the result, complete decomposition of the aromatic compounds occurs. The ability of microorganisms to decompose xenobiotics enables solving a number of environmental problems associated with both the use of chemical pesticides and the discharge of untreated industrial wastewater.

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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.