The fungus Gliocephalotrichum simplex as a source of abundant, extracellular melanin for biotechnological applications

Abstract

Melanins are commonly produced by bacteria, fungi, plants and animals, where they play a role in many biological functions. They protect organisms against UV and ionizing radiations. Their potential applications in biotechnological industries such as cosmetics and paints, where UV protection is required, are hampered by the lack of suitable organisms or methods to produce them abundantly. We report here the production of high amounts of extracellular melanin by the fungus Gliocephalotrichum simplex in cultures supplemented with tyrosine. Their typical UV-absorbance, as well as i.r., (13)C solid-state and (1)H NMR spectra indicated that the melanin is a eumelanin, being a copolymer of dihydroxyindole carboxylic acid and dihydroxyindole, associated with some carbohydrates and proteinaceous matter. Optimal culture conditions established by a Plackett-Burman experiment, followed by a full factorial experiment based on tyrosine and peptone yielded a maximum of up to 6.6 g melanin l(-1). The high yields of extracellular melanin from G. simplex enables its use in biotechnology.

Preparation of water-soluble melanin from squid ink using ultrasound-assisted degradation and its anti-oxidant activity

“…Figure 5 showed the 13 C CP/MAS NMR spectra for natural squid ink melanin and soluble fraction B. Both of the two samples showed similar peaks among three characteristic spectral regions as described in the previously literature for the NMR of the melanin (Adhyaru et al 2003;Tian et al 2003, Jalmi et al 2012: (1)δ10-95 ppm was assigned to aliphatic carbons, which was due to proteinaceous material; (2)δ95-165 ppm was assigned to aromatic carbons, including indole or pyrrole type carbons within the polymer; (3)δ165-200 ppm, carbonyl carbon atoms in amides, carboxylates and quinones, which came from the carbonyl in the oxidized quinone form of DHI and DHICA. More specifically, the signals near~δ30ppm and~δ50ppm were assigned to aliphatic groups which come from dihydroderivatives of DHICA, DHI (Knicker et al 1995;Adhyaru et al 2003;Tian et al 2003;Jalmi et al 2012); the signals near~δ103ppm was suggestive of C-3 of indole nucleus, which was from the anomeric carbon of carbohydrates; the peak near~δ130ppm was assigned to aromatic group; the signal near~δ174ppm was due to carbonyl group present as carboxylic acid group, which was derived from DHICA, and the degradation products of DHI and DHICA.…”

Production of Melanin Pigment by Fungi and Its Biotechnological Applications

“…In M. ruber, the use of glutamic acid as a nitrogen source showed promising results, either as stimulating the accumulation of extracellular pigments or contributing to increase the efficiency of the pigment production process [45]. The production of high amounts of extracellular melanin by the fungus Gliocephalotrichum simplex was obtained in cultures supplemented with tyrosine (2.5%) and peptone (1%) [64].…”

Physicochemical characteristics and antioxidant activity of arginine-modified melanin from Lachnum YM-346

“…The resonance at 3.5-4.0 ppm was assigned to the CH group that is connected to NH group. Peaks in the 7.0-7.5 ppm region may correspond to the indole or other aromatic heterocyclic ring of the melanin polymer chain (Jalmi, Bodke, Wahidullah, & Raghukumar, 2012;.…”