[Quantitative mycelial growth and antibiotic biosynthesis patterns in actinomycete producers of heliomycin]

The quantitative regularities of the mycelium growth and antibiotic biosynthesis were studied in submerged cultures of the heliomycin-producing organisms. The following regularities of the mycelium growth were observed: the growth of the growth tubes proceeds according to the exponential law (the first exponential phase of the culture growth), the growth of separate branching hyphae submits to the linear dependence, the total length of the branching mycelium increases exponentially (the second phase of the culture exponential growth). During the first exponential phase the specific rate of the antibiotic biosynthesis is equal to the specific rate of the mycelium growth and the synthesis of heliomycin balanced with the mycelium growth. During the second exponential phase the specific rate of heliomycin biosynthesis exceeds the specific growth rate which is evident of the antibiotic overproduction. The changes in the ratio of the specific growth rate and antibiotic biosynthesis coincide with the changes in the intracellular localization of heliomycin. When the synthesis of heliomycin is balanced with the culture growth, the antibiotic is in the form showing yellow luminescence. With the beginning of the antibiotic overproduction heliomycin in the form of granules with bright orange luminescence is detected in the mycelium along with the yellow luminescence form. It is suggested that formation of the granules during the antibiotic overproduction is one of the mechanisms of the antibiotic excess removal.