Microbial Production of Coloured Azaphilone Metabolites

Abstract

Azaphilones, fungal secondary metabolites of the pyranequinone structure, react with ammonia yielding vinylogous 4-pyridones. The pigments also react with amines, such as proteins, amino acids and nucleic acids, to form water-soluble pigments. Their most remarkable and valuable properties include the natural origin, yellow-red spectra, thermostability (in comparison with other natural red pigments), and easy derivatization. So far, they have been identified in a variety of fungal sources. Of the microorganisms tested, only genera Monascus, Penicillium and Chaetomium are good producers of azaphilone pigments. However, similar structures were also identified in Aspergillus ustus, Cochliobolus lunata, Talaromyces sp. and Emericella falconensis. The microorganisms could be a promising source of the new group of natural pigments for food and cosmetic industry.