Production and characterization of melanin pigments derived from Amorphotheca resinae

Abstract

As melanin has emerged as functional pigment with cosmetic, health and food applications, the demand for the pigments is expected to increase. However, the conventional sources (e.g. mushroom, hair, and wool) of melanin production entail pigments inside the substrates which requires the costly extraction procedures, leading to inappropriate scalable production. In this study, we screened 102 of fungal isolates for their ability to produce melanin in the supernatant and selected the only Amorphotheca resinae as a promising candidate. In the peptone yeast extract glucose broth, A. resinae produced the melanin rapidly during the autolysis phase of growth, reaching up 4.5 g/L within 14 days. Structural characterization of the purified melanin from A. resinae was carried out by using elemental analysis, electron paramagnetic resonance, C-13 solid-state nuclear magnetic resonance spectroscopy, and pyrolysis-gas chromatography-mass spectrometry in comparison with the standard melanins. The results indicate that the structural properties of A. resinae melanin is similar to the eumelanin which has a wide range of industrial uses. For example, the purified melanin from A. resinae has the potent antioxidant activities as a result of free radical scavenging assays. Consequently, A. resinae KUC3009 can be a promising candidate for scalable production of industrially applicable melanin.