[Effect of mineral nutrition sources on the growth and toxin formation of the entomopathogenic bacteria Bacillus thuringiensis].

Mineral composition of culture medium has been studied for its effect on the processes of growth, spore-and-toxin formation of entomopathogenic bacteria Bacillus thuringiensis. It has been shown that salts Na2SO4, Na2SiO3.9H2O, MgSO4.7H2O increase the yield of biomass and endotoxin; FeSO4.7H2O, CaCl2, MnSO4.4H2O increase only the yield of biomass; CdSO4.7H2O and CoCl2.6H2O--inhibit the processes of spore-and-toxin formation, but increase the cell titre. A complex of mineral salts has been found which takes positive effect on the biomass accumulation, delta-endotoxin synthesis and insecticide activity of the studied bacteria. It is shown that the drug "Gumat" besides other elements of the culture medium completely provides bacteria with necessary mineral compounds.