In this PhD thesis the microbiota composition of 20 gangues from coal pit waste heaps of Central Enrichment Plant “Chervonogradska”, coal pits “Vizejska” and “Nadija” from Chervonograd mining region is analysed. The gangue samples vary by the storage terms and chemical composition the same as by vegetative cover formation. The acidophilic sulfur oxidizing bacteria predominate ((59.4–159.9)×105 colony forming units/g abs. dry gangue) in waste heaps gangues. The quantity of nitrogen-fixing bacteria is low ((0.9–92.2)×105 colony forming units/g abs. dry gangue), but the number of cellulose decomposing microorganisms (90–100 % growing gangue clods), pedotrophic and oligotrophic microorganisms ((4.4–11.6)×105 colony forming units/g abs. dry gangue) are high.
In the gangues from naturally overgrown waste heap of coal pit “Vizejska” and in the majority of samples from recultivated waste heap of coal pit “Nadija” the processes of organic matter destruction prevail. It is confirmed by coefficients of pedotrophs (0.23–4.97), oligotrophs (0.05–0.94) and mineralization/immobilization (1.51–4.48). Catalase (0–1.48 ml 0.1 n solution of KMnO4/g air dry gangue for 1 hour), protease (0–0.80 mg aminoacids/g air dry gangue for 1 hour) and urease (0–2.34 mg N-NH4+/g air dry gangue for 1 hour) activities of gangue are low on the contrary to cellulase activity (0.13–15.8 mkg C6H12O6/ g air dry gangue for 1 hour).
40 strains of sulfur reducing bacteria were isolated from gangues of Chervonograd mining region coal pits waste heaps. According to the highest sulfidogenic activity two strains were selected and identified as Desulfuromusa sp. SV30 and Geobacter sp. SV35. Bacteria Desulfuromusa sp. SV30 perform dissimilatory sulfur reduction utilizing ethanol, fenol, glycine, aspartic acid and urea, while bacteria Geobacter sp. SV35 utilizes ascorbic acid and mannitol. Sulfur reductase activity of both strains is the highest in supernatant of cultural fluid. It depends on substrate concentration, pH and temperature of environment. Sulfur reductase activity of Desulfuromusa sp. SV30 is the highest at рН 7.5 and temperature 20–40 ºС (39.5–55.6 µmol HS-/min×mg of protein). Sulfur reductase activity of Geobacter sp. SV35 is the highest at рН 6.0 and 20 ºС (81.9 µmol HS-/min×mg of protein).
Bacteria Desulfuromusa sp. SV30 and Geobactersp. SV35 reduce Mn (IV), Cr (VI), Cu (ІІ), Fe (ІІІ) and are resistant to 0.5 mmol Cr (III) and Cr (VI) compounds. But strains differ by biomass accumulation and sulfidogenic activity while influence of 0.5–2 mmol copper compounds and 1–5 mmol iron compounds. Bacteria Desulfuromusa sp. SV30 shows high level of binding of 0.5–1 mmol Cu (ІІ) and 1 mmol Fe (ІІ) with produced HS- in the form of dissolved sulfides. Hydrogen sulfide, formed as a result of sulfur reduction, binds heavy metal ions in the form of insoluble metalsulfides.
To establish the interconnections between members of the microbial group, it’s enzymatic activity in the gangues and physical and chemical factors of the environment factor analysis by the method of normalized varimax was applied. The 33 variables were gathered into 8–10 factors in the formed matrices of factor loadings. Sulfur reducing bacteria became part of latent factors in every matrix: in gangues of coal pit “Vizejska” (72.5 % of factor dispersion) they are linked by inverted bonds with cellulose decomposing microorganisms, pH of the gangue and the chromium content; coal pit “Nadija” (28.2 % of factor dispersion) – by direct bond with urease activity, inverted bonds – with cellulose decomposing microorganisms and cellulase activity; Central Enrichment Plant (16.4 % of dispersion) – by direct bonds with microscopic fungi and urease activity, inverted bonds – with cellulose decomposing microorganisms, humidity and protease activity.
Coal ash from Dobrotvir thermal power station to gangue applied in proportion as 1 to 5 at the laboratory conditions leads to decrease gangue acidity from 2.88–5.53 to 4.32–7.01. At the majority of times, it also promotes the increase of acidophobic sulfur oxidizing, oligonitrophilic bacteria quantity. On the other hand coal ash applying causes decrease of the number of acidophilic sulfur oxidizing bacteria, bacteria that utilize mineral nitrogen forms, sulfur- and sulfate reducing bacteria as well as cellulose decomposing microorganisms. The mircoscopic fungi number changed differently after coal ash applying. Previously received data were confirmed after experiment in natural conditions (250 g coal ash/m2 ). In accordance with factor analysis results, the negative impact of acidity lowering after coal ash applying in laboratory conditions on quantity of sulfur-, sulfate reducing bacteria, assimilating mineral forms of nitrogen bacteria, cellulose decomposing microorganisms.
