[Effect of microelements on accumulation of biomass and exopolysaccharides in Bacillus subtilis strains]

Different trace elements in the composition of nine synthesized complex compounds of N-oxides of pyridine derivatives have been studied. It has been shown that the effect of trace elements included in the composition of nutrient media on accumulation of cells and exopolysaccharides (EPS) by the strains of B. subtilis is sufficiently expressed; it is also diverse and depends on the element nature, concentration as well as on peculiarities of the bacillus cultures. The studied trace elements are separated into the conditional groups: the elements intensifying the above processes (manganese and lithium); elements repressing the processes (copper and cadmium); those retarding the accumulation of biomass but activating the secretion of EPS (nickel, boron, cobalt, zinc, iron). Concentrations of trace elements optimal for the studied productivity indices of strains have been established. Peculiarities of the trace element effect in paired and ternary combinations on the growth and biosynthesis of EPS during cultivation of strains in liquid media have been revealed.