Investigation of Filamentous Fungi Producing Safe, Functional Water-Soluble Pigments

Abstract

The production of water-soluble pigments by fungal strains indigenous to South Korea was investigated to find those that are highly productive in submerged culture. Among 113 candidates, 34 strains that colored the inoculated potato dextrose agar medium were selected. They were cultured in potato dextrose broth and extracted with ethanol. The productivity, functionality (radical-scavenging activities), and color information (CIELAB values) of the pigment extracts were measured. Five species produced intense yellowish pigments, and two produced intense reddish pigments that ranked the highest in terms of absorbance units produced per day. The pigment extracts of Penicillium miczynskii, Sanghuangporus baumii, Trichoderma sp. 1, and Trichoderma afroharzianum exhibited high radical-scavenging activity. However, the S. baumii extract showed moderate toxicity in the acute toxicity test, which limits the industrial application of this pigment. In conclusion, P. miczynskii KUC1721, Trichoderma sp. 1 KUC1716, and T. afroharzianum KUC21213 were the best fungal candidates to be industrial producers of safe, functional water-soluble pigments.

Fungal Pigments and Their Prospects in Different Industries

“…Monascin (yellow), monascorubramine (red), monascorubrin (orange), ankaflavin (yellow), citrinin (yellow), rubropunctamine (purple-red), rubropunctatin (orange), N-glucosylrubropunctamine (red), N-glucosylmonascorubramine (red), monarubrin (pale yellow), rubropunctin (pale yellow) Uncharacterized (yellow) [70,71] Trichoderma parceramosum Uncharacterized (red) [72] Cordyceps farinosa (Formerly Known as Isaria farinosa)…”

“…DgCr22.1b Talaroxanthone (yellow) [107] Talaromyces siamensis, Talaromyces sp. Uncharacterized (red) [71,108] Talaromyces sp. N-threonine rubropunctamine (red) [72] Hamigera avellanea (Formerly Known as Talaromyces avellaneus)…”

“…(Figure 3b) [100,101,103,107,109]. An uncharacterized red pigment was discovered from Talaromyces siamensis under submerged fermentation [71]. Moreover, other species of Talaromyces, Talaromyces aculeatus, Talaromyces atroroseus, Talaromyces albobiverticillius, Talaromyces cnidii, Talaromyces coalescens, Talaromyces pinophilus, Talaromyces purpurogenus, Talaromyces funiculosus, Talaromyces amestolkiae, Talaromyces ruber, Talaromyces stollii, and Talaromyces verruculosus have been reported to have the ability to produce Monascus-like azaphilone pigments ( Figure 4) [25,106].…”

“…Several hydroxyanthraquinones such as pachybasin, chrysophanol, emodin, T22 azaphilone, 1-hydroxy-3-methyl-anthraquinone, 2,4,5,7-tetrahydroxyanthraquinone, 1,3,6,8-tetrahydroxyanthraquinone, and 1,8-dihydroxy-3-methyl-anthraquinone, have been reported from different species of Trichoderma (Trichoderma harzianum, Trichoderma polysporum, Trichoderma viride, and Trichoderma aureoviride) (Figure 7a) [25], whereas Trichoderma afrharzianum, Trichoderma pyramidale, and Trichoderma sp. 1 are reported to produce uncharacterized yellow pigments in submerged fermentation [71]. Studies have also revealed that certain species of Neurospora, such as Neurospora crassa, Neurospora sitophila, and Neurospora intermedia produce a variety of carotenoids such as phytoene, β-carotene, γ-carotene, lycopene, neurosporene, and neurosporaxanthin (Figure 7b) [25,26,90].…”

“…Other pigments, such as orevactaene produced from Epicoccum nigrum, emodin, ω-hydroxyemodin, and emodic acid from Hamigera avellanea (formerly known as Talaromyces avellaneus) are also known (Figure 3b, Figure 9b) [33,36,37,39,41,109]. Recently, fungi such as Sanghuangporus baumii and Clonostachys intermedia have been found to produce a yellow pigment under submerged fermentation [71]. Production of melanin was reported from different groups of fungi such as Phyllosticta capitalensis, Xylaria polymorpha, Trametes versicolor, Inonotus hispidus, Oxyporus populinus, Fomes fomentarius, Exophiala dermatitidis, Tuber melanosporum, Sporothrix schenckii, and Cryptococcus neoformans [29,34,35,44,80,81,83].…”