Mìkrobìologìâ ì Bìotehnologìâ (Apr 2019)
RESISTANCE OF ACIDOPHILIC CHEMOLYTOTROPHIC BACTERIA ISOLATED FROM TECHNOGENIC RAW MATERIALS TO HEAVY METALS
Abstract
Aim. Determination of resistance to heavy metal ions of acidophilic chemolithotrophic bacteria isolated from dump products of fuel-energy complex of Ukraine. Methods. Traditional microbiological: cultivation of strains were carried out with using of Silverman-Lundgrem 9K medium in the presence of copper, zinc, nickel, cobalt and cadmium ions in the concentration range 0.5–12.0 g/dm3 at intervals 0,5 g/dm3 , in the presence of lead in the concentration range 0.25–1.50 g/dm3 at intervals 0,05 g/dm3 ; crops carried out with a stroke; cultivation of mesophilic strains was carried out at the temperature of 35.0±0.2 °C, moderately thermophilic – at 50.0±0.2 °C within seven days; the results were recorded visually by comparing the experimental options with the control ones; the control was 9K medium without metal ions. Results. The results indicate a high level of resistance of isolated strains of the genera Acidithiobacillus and Sulfobacillus to various heavy metal ions. The metals minimum inhibitory concentrations (MIC) for the studied strains were several times higher than their content in dump products of fuel-energy complex. A series of metal ions toxicity in relation to the isolated strains has been established: Pb2+ ion was the most toxic (MIC for all the strains it was in the range of 0.35–0.70 g/dm3 ), the least toxic was Cu2+ ion (MIC reached 11.5 g/dm3 ). A number of resistances of isolated acidophilic chemolithotrophic bacteria of the genera Acidithiobacillus and Sulfobacillus with respect to toxic metal ions has been determined. The strains isolated from coal waste dumps possessed the maximum resistance, the minimal strains were those isolated from coal burning wastes, as well as the typical ones. Conclusion. The strains of acidophilic chemolithotrophic bacteria isolated from technogenic raw materials belong to multiresistant ones, since they showed a high level of resistance to a wide range of heavy metal ions in a wide range of concentrations. The resistance of strains depends on their individual characteristics and sources of isolation. Identified interspecific and intraspecific differences of the strains by their resistance, is associated with various physiological and genetic factors.
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