Natural Melanin Synthesized by Aureobasidium pullulans Using Food Wastes and its Characterization

Food wastes cause economic losses and environmental problems. Hence, ability to transform food wastes into high-value added products is highly attractive. The aim of this study was to produce melanin pigments by fermentation that include wide potential uses in agriculture, cosmetics and pharmaceutical industries using domestic wastes such as melon peel, watermelon peel and carrot peel and industrial by-products such as whey and molasses. Material and Methods: Two Aureobasidium pullulans strains were assessed for melanin production. Fourier-transform infrared spectroscopy, scanning electron microscope, zeta potential, ultraviolet absorbance and solubility assays were carried out to characterize produced melanin nanoparticles. Results and Conclusion: The highest intracellular (0.19 g l-1) and extracellular (3.52 g l-1) melanin concentrations were produced by Aureobasidium pullulans NBRC 100716 using carrot peel extracts as fermentation media. Results of characterization were compared with those of synthetic melanin used as standard and the produced nanoparticles were validated. Particle sizes of the nanoparticles ranged 10-760 nm with negative charges, as suggested by previous literature. Results showed that carrot peel was a good candidate, which could be used for the production of high value-added melanin. When carrot peel extract was used as a fermentation medium, characteristics of the melanin produced by Aureobasidium pullulans NBRC 100716 strain were similar to those of synthetic melanin.