MORPHOPHYSIOLOGICAL PROPERTIES OF SULFATE-REDUCING BAСTERIA ISOLATED FROM THE SYSTEM OF LVIV WASTEWATER TREATMENT

Abstract

Aim: to isolate the sulfate-reducing bacteria from the system of sewage treatment in the city of Lviv, to study the morphological and physiological properties of isolated microorganisms. Methods. The research object was a strain of sulfatereducing bacteria, isolated from the system of treatment the domestic and industrial wastewater of the city of Lviv. Water and sludge samples were taken from the primary, secondary settlers and active sludge of the wastewater treatment system of the city of Lviv by the Stolbinov-Ryabov method. The isolated strain of bacteria was cultivated on a selective medium. Identification of the isolated strain of microorganisms was carried out according to morphophysiological features in accordance with the Bergey's manual. The morphology of the studied cultures was studied by electron microscopy. To determine the presence of spores in the cells, they were stained by the method of Peshkov. The content of sulfate and hydrogen sulfide in the culture liquid was determined photometrically. Results. From active sludge of the aerotank system of the treatment facilities of the city of Lviv allocated a strain of spore-forming sulfate-reducing bacteria, which also, in the absence of sulfate-ion, can use elemental sulfur as a final electron acceptor. In the presence of sulfate ion bacteria use lactate and acetate as a source of carbon. Microorganisms are in the form of short rods, Gram-negative. The isolated strain of bacteria belongs to neutrophilic and mesophilic microorganisms. The isolated strain is identified as Desulfotomaculum AR1 by the morphological and physiological properties. Conclusions. Sulfate-reducing bacteria Desulfotomaculum AR1, isolated from active sludge of aerotanks of the wastewater treatment system in the city of Lviv, accumulate up to 18 mM hydrogen sulfide in the presence of lactate or acetate in the medium as a source of carbon. In addition to sulfate ions, bacteria reduce elemental sulfur, using it as a final electron acceptor.