Production of pigments by actinomycetes has been utilized as an important cultural
characteristic in describing the organisms. Nevertheless, very little is
known about the exact chemical nature of pigments, because the
formation of pigment is influenced by the pH of the medium,
aeration, temperature of the growth and carbon and nitrogen sources.
Actinomycetes also synthesized and excrete dark pigments melanin
or melanoid, which considered to be useful criterion for taxonomical
studies 2-4