Co-catalysis of melanin degradation by laccase-manganese peroxidase complex from <i>Trametes hirsuta</i> OK271075 for application in whitening cosmetics

Melanins are a complex natural pigment that darken the skin, a phenomenon regarded as an esthetic problem in tropical countries such as Indonesia. Melanin can be degraded by various oxidative enzymes such as laccase (Lac) and manganese peroxidase (MnP) which are produced by white rot fungi (WRF). In the current study, we successfully obtained a partial purified Lac-MnP from a tropical WRF called Trametes hirsuta OK271075. Co-catalysis of Lac and MnP in the melanin degradation existed as indicated by the enhancement of degradation upon the addition of mediators for the respective enzymes. The highest degradation was up to 42% in the presence of TEMPO (0.2 mM) and MnSO₄-H₂O₂ (0.75 mM, 0.2 mM) as mediators. The increment was up to 20% compared to treatment without mediators. A higher degradation rate achieved when specific mediators of the enzymes were utilized indicated a synergistic effect of both enzymes that could be used simultaneously for melanin degradation. FTIR and FESEM analysis revealed significant changes in melanin structure between enzyme-treated and untreated melanin. Melanin granules were cracked and exfoliated due to an enzyme attack. Based on Pyrolysis-GCMS analysis, several compounds such as phenols, epoxides, ketones, and carboxylic acids were found in higher amount in the enzyme-treated than untreated melanin. This finding revealed the potency of a new isolated T. hirsuta for new enzyme applications in biotechnology fields, especially to degrade melanin for application in natural whitening cosmetics.