Melanins form a diverse group of pigments synthesized in living organisms in the course of hy-droxylation and polymerization of organic compounds. Melanin production is observed in all large taxa from both Pro-and Eukaryota. The basic functions of melanins are still a matter of controversy and speculation, even though their adaptative importance has been proved. Melano-genesis has probably evolved paralelly in various groups of free living organisms to provide protection from environmental

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... s conditions, but in pathogenic microorganisms it correlates with an increased virulence. The genes responsible for melanization are collected in some cases within operons which find a versatile application in genetic engineering. This review sumarizes current views on melanogenesis in Pro-and Eukaryotic microorganisms in terms of their biotechnological and biomedical importance.