Synthesis of selenium and silver nanobiocomposites and their influence on phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus

Selenium and silver nanobiocomposites were synthesized based on potentially metabolizable for microbes polysaccharides arabinogalactan and starch, as well as based on humic compounds obtained from peloids (therapeutic muds) and brown coals of Mongolia. Their influence on the phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus was studied. The absence of a negative effect of nanocomposite precursors (arabinogalactan, starch, and humic compounds) on the bacterial growth was demonstrated. All the nanocomposites studied were found to reduce the bacterial growth. Vital dyes were used to reveal that after 24 h of incubation, the examined nanobiocomposites caused changes in the morphology of the cells: the bacteria grew shorter and thicker, which led to their death. The nanoselenium composite in starch and the nanosilver composite in humic substances possessed the greatest effects. The results obtained indicate the presence of bacteriostatic and bactericidal effects in a number of nanocomposites studied.