Dye has played an important role and always been an essential element of human life. Early humans extracted pigments from various plants, and also used the natural pigments from different mushrooms as fabric dyes. In addition to fabric dyes, pigments are also used in different fields, and because of this, the demand for pigments is increasing day by day. Because natural pigments are unstable and expensive, they can no longer meet the needs of human beings, so synthetic pigments began to appear in the 19th century. Interestingly, under the influence of modern food safety considerations and people's pursuit of a healthy life, natural pigments have become the first choice for humans to choose dyes, especially in the food industry or animal husbandry. Many synthetic dyes have been proven to be harmful to health and even have cancer risks.

The application of plant-origin pigments has been around for years, but fungal- origin pigments remain a surprisingly understudied field. The main difference between fungal pigments and plant pigments is that fungal pigments do not contain chlorophyll and anthocyanins. In contrast, fungal pigments from some species are mostly betalains and terpenoids, among which carotenoids are common. four main synthesis pathways of fungal pigments are summarized below:

1.     Polyketide pathway, such as melanin and flavin

2.     Shikimate pathway, such as shikimic and chorismic acids are used to manufacture the important amino acids tyrosine, tryptophan, and phenylalanine. Various important building components of many colours found in fungi, such as benzoic, arylpyruvic, and cinnamic acids, are produced from tyrosine and phenylalanine precursors.

3.     Terpenoid synthetic pathway, such as carotenoids belonging to the terpenoid family

4.     Nitrogenous metabolic pathways that ensure the formation of various fungal pigments.

In the case of carotenoids, it is a variety of pigments found in nature. Not only are they an important part of plants that aid in photosynthesis, but they are also found in more than 200 known fungal species. The role of these pigments is to protect the fungus from UV and oxidative damage. In the future, while people are trying to find natural pigments, fungi may be a treasure trove.

Reference:

Ahmad, N. et al. 2022. Roles of Medicinal Mushrooms as Natural Food Dyes and Dye-Sensitised Solar Cells (DSSC): Synergy of Zero Hunger and Affordable Energy for Sustainable Development. Sustainability 2022, 14, 13894. https://doi.org/10.3390/su142113894