[The role of amino acids in intensification of Bacillus subtilis exopolysaccharide biosynthesis in deep growth conditions].

The influence of various combinations of amino acids on the Bacillus subtilis growth activity and exopolysaccharide biosynthesis has been studied. The effects of amino acid additions on these two processes have appeared to be different. The strains reveal the specificity in amino acids requirements while cultivation in liquid media. To judge by the average indirect contributions, the growth as well as the exopolysaccharide biosynthesis of B. subtilis strain 39 have been significantly affected by introduction of alanine, valine, phenylalanine, tryptophane and glycine in triple combinations into the culture medium. The exopolysaccharide production and growth of B. subtilis strain 51 have been influenced markedly by methionine, leucine, isoleucine, cystine, glycine, tryptophane and alanine. Addition of different combinations of these amino acids makes it possible to obtain the 20.2-56.3% higher biomass amounts with the simultaneous 26.8-89.6% increase of exopolysaccharide yield.