Prodiginine (prodigiosin-like) pigments from Streptomyces and other aerobic Actinomycetes

About 95 microorganisms, mainly streptomycetes, were examined for prodiginine pigments. The test methods, including some media for stimulating pigment production, are given. All nine strains which produced prodiginine pigments were characterized and the pigments identified. The results were used to propose structures for five prodigiosin-like pigments from actinomycetes reported in the literature between 1947 and 1964. Streptoverticillium sp. 26-1 furnished good yields of butylcycloheptylprodiginine (I), whose antimicrobial activity is given.