Abstract

Nine strains among 180 Streptomyces isolates produce a diffusible dark brown pigment on both peptone-yeast extract agar and synthetic tyrosine-agar. They also show the positive reaction to L-tyrosine or L-dopa substrates. The pigment has been referred to be as merely as dark brown water-soluble pigment, as melanoid or melanin. The different carbon and nitrogen sources which influence the pigment production in the Streptomyces isolates were also investigated, and the carotenoid content in the pigment was analyzed. The melanin formation in the Streptomycesspecies is the key feature for the classification of the Stretomyces group.

Key words: Pigment, melanin, Streptomyeces, taxonomy.