STRAIN DEGENERATION DURING CONTINUOUS CULTURE OF A CHLORAMPHENICOL-PRODUCING STREPTOMYCES VENEZUELAE

Abstract

Instability of growth characteristics and chloramphenicol production was observed during long-term continuous cultivations of a Streptomyces sp. The occurrence of these variations was attributed to a continuous population selection.Fermentation patterns are presented for growth in a complex and in a synthetic medium, at different replacement times. The culture degeneration pattern was influenced by the type of medium used and by the replacement time. A rich complex medium created the most favorable conditions for the maintenance of an antibiotic-producing population.Growth on the walls took place when cultures were grown in the complex medium with a fast replacement time. Under these conditions no decrease in chloramphenicol yield was observed, even after 76 replacements of the medium. Possibly a population closely related to the initial one was maintained on the walls, and thus replacement by non-producing populations was avoided. Application of this method is suggested as a means for maintenance of culture stability in continuous industrial fermentation.