Cycloheximide is a naturally occurring fungicide produced by the bacterium "Streptomyces griseus". Streptomyces griseus is a species of bacteria in the genus "Streptomyces" commonly found in soil. Spectinomycin is industrially produced by fermentation of the bacterium "Streptomyces spectabilis". Streptomycin was discovered in 1943 from "Streptomyces griseus". Streptomycin is produced by "Streptomyces griseus". Streptavidin is a 52.8 (tetramer) kDa protein purified from the bacterium "Streptomyces avidinii". It came from a similar soil bacterium named Streptomyces rimosus. "Streptomyces" and other actinobacteria are major contributors to biological buffering of soils. Streptomyces avermitilis is a bacterium species in the genus "Streptomyces". It is produced by fermentation of certain type of the bacterium "Streptomyces". It is produced naturally by the bacterium "Streptomyces fradiae". It is produced by the bacterium "Streptomyces conglobatus". It is a sesquiterpenoid that was already known from the soil bacterium "Streptomyces albidoflavus". It is made from the bacterium "Streptomyces noursei". Natamycin was first isolated in 1955 from fermentation broth of a "Streptomyces natalensis" cell culture..