L. KOZHUHAROVA and V. GOCHEV
University of Food Technologies, Department Biotechnology, BG - 4002 Plovdiv, Bulgaria
KOZHUHAROVA, L. and V. GOCHEV, 2004. The effect of p-aminobenzoic acid and aromatic amino acids on the levorin biosynthesis by Streptomyces levoris 99/23. Bulg. J. Agric. Sci., 10: 735-740
The effect of p-aminobenzoic acid (p-ABA) and the aromatic amino acids phenylalanine, tryptophan and tyrosine upon the levorin biosynthesis by Streptomyces levoris 99/23 on synthetic and complex culture media was studied. The maximum quantity of biomass and levorin was obtained when 0.05 g/l of p-ABA was added to the synthetic culture medium and 0.10 g/l of p-ABA was added to the complex culture medium. p-ABA had a more pronounced stimulating effect on a syntethic culture medium. The highest stimulating effect of p-ABA was observed when it was added to the media 48 hours after inoculation. Phenylalanine and tryptophan suppressed the S. levoris 99/23 development and the levorin biosynthesis. Tyrosine, however, did not cause such changes. The antibiotic concentration reached its highest values at the 120th hour after inoculation on both media, which corresponded to the stationary phase of the producer development.