Influence of medium composition on sporulation by Streptomyces coelicolor A3(2) grown on defined solid media.

Reproducible sporulation using solid-plate cultures of Streptomyces coelicolor A3(2) was obtained on a defined medium with glucose as the primary source of carbon and sodium nitrate as the sole source of nitrogen. The type of agar used as a solidifying agent, and the inclusion of trace salts to the medium, Significantly affected sporulation. An interrelationship between the medium carbon to nitrogen ratio and sporulation was observed, with clear promotion of spore formation under nitrogen-limited conditions, whilst carbon-limited conditions suppressed sporulation. The influence; of medium phosphate upon sporulation is also reported, with high concentrations exerting an inhibitory effect.