Fungal colorants in applications – focus on Cortinarius species.

Secondary metabolites in fungi offer an interesting source of bio‐based compounds that could be used as colorants in many applications. From a historical point of view, fungal natural dyes have been used more rarely than plant‐based dyes. This paper investigates the potential of fungal colorants, using Cortinarius species as examples. In our research, fruiting bodies of the fungi Cortinarius sanguineus and Cortinarius semisanguineus were used as sources of anthraquinone dyestuffs. From 10 kg of fresh fruiting bodies, 60 g of anthraquinone powder was obtained, 6% of the dry weight content. The most abundant compounds were emodin, dermocybin and their glucosides, which formed over 90% of the total dyestuff amount. Pure emodin and dermocybin, as well as the crude water extract, were used for the dyeing and printing of natural and synthetic fibres. Conventional mordant techniques and high‐temperature (HT) disperse dye techniques were applied, and light and washing fastness were tested according to International Organization for Standardization standards. Our experiments show that the yields of dye powders extracted from fungi are reasonable compared with the yields of, for example, madder (Rubia tinctorum). Natural anthraquinones produce strong and bright colours on several types of fibres. In particular, for HT disperse dyed polyester, the light and washing fastness properties were excellent. Anthraquinones are common in nature and there are many fungal species which produce them, so there are a variety of possibilities for growing fungi. The use of large‐scale cultures is an interesting perspective for future biocolorant production. [ABSTRACT FROM AUTHOR]