THE ROLE OF AMINO-ACIDS IN THE ENHANCEMENT OF EXOPOLYSACCHARIDE BIOSYNTHESIS IN SUBMERGED CULTURE OF BACILLUS-SUBTILIS

The influence of various combinations of amino acids on the growth and exopolysaccharide biosynthesis of Bacillus subtilis culture has been studied. The addition of amino acids to the medium produced different effects on these two processes. B. subtilis strains exhibit specificity in amino acid requirements when cultivated in liquid media. Growth and exopolysaccharide biosynthesis of the B. subtilis strain 39 were most significantly influenced (judging by the mean indirect positive effect) by the addition of alanine, valine, phenylalanine, tryptophan, and glycine introduced in the culture medium by triple combinations, whereas methionine, leucine, isoleucine, cystine, glycine, tryptophan, and alanine introduced in the same manner exerted a most pronounced effect on the exopolysaccharide production and growth of B. subtilis strain 51. Addition of different combinations of these amino acids makes it possible to obtain the significant increase of the biomass yield (by 20.2 - 56.3%) and exopolysaccharide yield (by 26.8 - 89.6%).