Production of natural edible melanin by Auricularia auricula and its physicochemical properties

• The mathematical model obtained is proven to be efficient in our current study.
• This study identifies critical factors in melanin production by A. auricula.
• The highest yield of melanin (2.97 g/L) was 2.14-fold higher compared to the control.
• The physicochemical properties of melanin from A. auricula were firstly investigated.
• This melanin had better thermostability and light resistance.

Fermentation conditions of natural edible melanin by Auricularia auricula were optimized to obtain a high melanin yield and physicochemical properties of melanin were firstly investigated. The results indicated that yeast extract, tyrosine and lactose have significant effects on melanin production. Under the proposed optimized conditions, the melanin experimental yield (2.97 g/L) closely matched the value (3.04 g/L) predicted by the second-order model, which provided a statistically prediction of media in submerged fermentation of A. auricula. The yield achieved was 2.14-fold higher compared to the control. It was firstly revealed that tyrosine could stimulate melanin synthesis in A. auricula. The results showed that this melanin had better thermostability and light resistance, and its solubility was relatively high under alkaline conditions. Zn2+ and Cu2+ could result in melanin precipitation. The results should be useful for the efficient production of melanin and enable numerous applications in food, cosmetics, pharmacology, medicines and other fields.