# Production of Fungal Pigments: Molecular Processes and Their Applications
## 5 Application of Pigments: Market Analyses and Future Trends
The pigments derived from spalting fungi possess such traits as resistance to UV exposure, color fastness, and light fastness under unmodulated conditions, which render them po tential novel applications in the wood, painting and textile industry [164; 169]. At present, the following fungi and their pigments have attracted significant academic and applied interests: _Scytalidium cuboideum_, which produces a red pigment draconin red [167]; _Scytalidium gandomemophthora_, producing an undefined yellow pigment [170]; and _Chlorociboria aeruginosa_ (Oeder), producing xylindein, a blue-green pigment. Xylindein, a naphthoquinone fungal pigment with enhanced stability, was recently reported as a promising material for the organic semiconductor industry. This pigment was demonstrated to possess high photostability, electron mobility up to 0.4 cm\({}^{2}\)/(V s) in amorphous films, and thermally activated charge transport and photo-response with activation energies of \(\sim\)0.3 and 0.2 eV, respectively [171; 172]. The excellent optical and electronic properties of xylindein solutions and films was found to be attributed to the presence of xylindein tautomers and aggregates [172]. This finding helps shed light on the exploitation of biocompatible and sustainable organic (opto) electronics derived from fungal pigments in the field of material engineering. Nature offers the fascinating source of safe colors and lead biomolecules for drug discovery. However, limitations such as season-dependent raw material availability and variation in pigment profile pertaining to the colorants of plant origin cannot be ignored in comparison to those of fungal origin. As shown above, pigmented fungi are an enormous compound reservoir for a variety of pigments, including those that are absent in plants such as azaphilones [134]. The main challenge of large-scale production of fungal pigments lies in the difficulty in increasing the yield of desirable pigment(s) while minimizing the production of unwanted substances. However, with the rapid advancement in genetic and metabolic engineering, such major biological traits would be addressed with respect to maintaining the robustness of fungal strains and to eliciting higher pigment yields. Selection of prolific fungal strains without mycotoxin co-production and a lowered energy input are the key factors determining market significance. _Monascus_ pigments produced by _Monascus_ species without citrinin represent a promising area, awaiting legislative approval in the US and the European Union. To ensure their safe supplementation in foods, such pigments must undergo lengthy toxicology testing in line with legislation and regulations in each country or area. Furthermore, the functionalities of fungal pigments other than dyeing power, for instance, antioxidant, antimicrobial, anticancer, anti-inflammatory, and immunomodulatory properties, have stimulated dramatic research interests in such compounds, as they have the potential to be lead biomolecules in the discovery and development of pharmaceuticals to treat human diseases, including cancer, infection, and metabolic disorders. Fungal pigments are commonly bioactive molecules produced mainly in response to stress conditions, and a large proportion of pigment production is found in isolates recovered from stressful environments such as ice samples, aqueous environments with high salinity, and remote glacial areas in Antarctica, pinpointing fungal pigmentation as an adaptative strategy to unfavorable conditions, i.e., cold and high-UV environments [173]. In this context, untapped habitats in Antarctica and marine environments are potentially rich niches for bioprospecting pigment-producing fungi in the future. The next decades will witness more and more pigment production using fungal cell factories.