Properties and structure of the melanin from Lachnum brasiliense

The melanin produced by Lachnum brasiliense 84-2 is soluble in NaOH solution and dimethylsulfoxide, slightly soluble in water, and not in methanol, ethyl acetate, HCl, anhydrous ethanol, chloroform, acetone and acetonitrile. The melanin is stable in pH≥7, but deposit in pH≤6 The melanin shows stable to temperature, sunlight, ultraviolet light, sodium benzoate, citric acid, sucrose, K+, Na+, Ca2+, Al3+, Cu2+and Na2SO3 but unstable to Mg2+, Fe3+, Mn2+and H2O2. Scanning electron microscopy indicates that the melanin is a kind of sheet crystalloid whose surface is anomalistic. Infrared spectrum analysis shows that it has functional groups of aryl, -OH, -NH, -COOH and thiazinyl. It is concluded that the melanin has the structure model of both eumelanin and pheomelanin.