PHYSIOLOGICAL AND BIOCHEMICAL CHARACTERISTICS OF METAL-RESISTANT STRAINS OF MICROORGANISMS FROM ANTARCTIC BIOTOPES
Komplikevych S, Hruna I, Maslovska
O. Ivan Franko National University of Lviv
The unique conditions of Antarctic biotopes (Margesin, Miteva, 2011) are the reason for the presence of a number of adaptations in the microorganisms of these biotopes (Gupta et al., 2020), in particular resistance to heavy metal ions (Tashirev, 2012). Metal-resistant strains play an important role in biotechnological processes.
The aim of the work was to study the properties of metal-resistant bacteria isolated from Antarctic habitats. Metal resistance of microorganisms was determined by the ability to grow in TSB media with 2-100 µM CdCl2×2.5H2O, 0.25 – 1 mM FeSO4×7H2O, 0.25 – 5 mM K2Cr2O7, 2-10 mM CuCl2×2H2O, 15-50 mM MnCl2×4H2O. Catalase activity was detected by reaction with 10% H2O2 solution; oxidase – using strips with N,N-dimethyl-p-phenylenediamine oxalate and α-naphthol. The ability to use carbon sources was determined by growth on Hiss media. Nitrogen fixation ability – by growth on Ashby medium. The formation of NH3 and H2S – during growth in TSB media, using indicators. The ability to reduce nitrates – by qualitative reactions after cultivation on Giltay medium. Physiological properties were detected using Remel RapID™ONE Kit. Amylase, lipase, proteolytic, cellulase, agarase activity was detected by the ability to metabolize starch, twin-20, gelatin, cellulose, agar. Molecular genetic characterization was performed after sequencing of the 16S rRNA gene.
Bacteria Paenibacillus tundrae 5A_101 that according to the 16S rRNA analysis have 100% homology with Paenibacillus tundrae Ab10b, are resistant to 50 μM Cd2+, 1 mM Fe2+, 2 mM Cu2+, 1 mM Cr(VI). Catalase and oxidase-negative. During growth in TSB media, H2S is formed. Using lactose, maltose, mannose, sucrose, and mannitol form an acid. Characterized by arginine decarboxylase, ornithine decarboxylase, lysine decarboxylase, β-galactosidase, amylolytic, agarase, and lipolytic activities. Able to fix N2. Capable of nitrification and oxidation of thiosulfate. The nucleotide sequence of 16S rRNA of Pseudomonas yamanorum 9.9_102 strain was 99.86% identical to the 16S rRNA sequence of P. yamanorum 27E2 strain. Bacteria are resistant to 0.1 mM Cd2+, 1 mM Fe2+, 1 mM Cr(VI), 2 mM Cu2+, 25 mM Mn2+. Use sucrose, maltose, mannose, lactose, dulcite, inositol, mannitol, sorbitol. In media with lactose and maltose form acid. Possess lipolytic, protease, and amylolytic activity. During growth in TSB media, NH3 is formed. Able to fix N2. Assimilate urea.
Metal-resistant strains P. tundrae 5A_101 and P. yamanorum 9.9_102 are characterized by a wide range of enzymatic activity and are promising for the development of biotechnologies for heavy metal-contaminated wastewater treatment.
This study was performed and partially funded under the State Target Scientific and Technical program of research in Antarctica for 2011–2020 within project.