Characterization of melanin and optimal conditions for pigment production by an endophytic fungus, Spissiomyces endophytica SDBR-CMU319

Abstract

Melanin is a natural pigment that is produced by filamentous fungi. In this study, the endophytic species, Spissiomyces endophytica (strain SDBR-CMU319), produced a brown-black pigment in the mycelia. Consequently, the pigment was extracted from the dried fungal biomass. This was followed by pigment purification, characterization and identification. Physical and chemical characteristics of the pigment showed acid precipitation, alkali solubilization, decolorization with oxidizing agents, and insolubility in most organic solvents and water. The pigment was confirmed as melanin based on ultraviolet-visible spectroscopy, Fourier-transform infrared, and electron paramagnetic resonance spectra analyses. The analyses of the elemental composition indicated that the pigment possessed a low percentage of nitrogen, and therefore, was not 3,4-dihydroxyphenylalanine melanin. Inhibition studies involving specific inhibitors, both tricyclazole and phthalide, and suggest that fungal melanin could be synthesized through the 1,8-dihydroxynaphthalene pathway. The optimum conditions for fungal pigment production from this species were investigated. The highest fungal pigment yield was observed in glucose yeast extract peptone medium at an initial pH value of 6.0 and at 25°C over three weeks of cultivation. This is the first report on the production and characterization of melanin obtained from the genus Spissiomyces.

Fungal Melanin and the Mammalian Immune System

“…Melanins are a family of structurally complex dark pigment polymer present in all biological kingdoms [ 1 ]. The polymer is made up of covalently linked indoles, but the overall structure is granular; however, detailed structures are not well characterized because it is a collection of polymers with mixed pre-indole structures [ 2 ].…”

Analytical Pyrolysis of the Fungal Melanins from Ochroconis spp. Isolated from Lascaux Cave, France

“…The critical problem in the study of melanins is the obtaining of a pure macromolecule without mixture of any other cell components. Common isolation procedures imply an extraction with an alkaline solvent and further precipitation in acid media [13,19,110]. This protocol co-extracts a wide diversity of components, associated with the fungal cell wall.…”

“…98), diketodipyrrole (peak 81) and the presence of nitriles (peaks31,34,44,92,105,107, 118, 119) and amides (peaks110, 115, 116). As expected, due to the previous pyrolysis of polysaccharides at 300 • C, carbohydrates markers were almost absent.Aromatic compounds were represented by the series of alkylbenzenes (C 1 -C 18 ) (e.g., peaks 4, 10, 75, 113, 117), naphthalene and methylnaphthalene (peaks 40, 52), phenanthrene (peak 86), while phenolic compounds were represented by phenol (peak 15), methylphenol (peak 28), methoxyphenol (peak 30), ethylphenol (peak 37), etc.…”

A Facile Alternative Sustainable Process for the Extraction and Purification of Microbial Melanin

“…1 The increased interest in melanin research is justified by its numerous biofunctions, such as colouration, camouflage, photo-and radio-protection, energy transducer, antioxidant, thermoregulator, chemoprotectant, antitumor, antiviral, antimicrobial, immunostimulant, anti-inflammatory, and detoxification. 2 Microbial melanins have advantage over synthetic melanin and other natural melanins derived from plants and animals, in terms of easy and safe production, ecofriendliness, low cost, raw culture medium components, and biodegradablity. 3 Melanin is formed by oxidative polymerization of phenolic-and indolic-compounds by the enzymes tyrosinase and laccase.…”