Co-catalysis of melanin degradation by laccase-manganese peroxidase complex from Trametes hirsuta 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.黑色素是一类可使皮肤变黑的复杂天然色素，在印度尼西亚等热带国家，该现象被视为美学问题。黑色素可被多种氧化酶降解，这些酶包括白腐真菌（white rot fungi，WRF）分泌的漆酶（laccase，Lac）与锰过氧化物酶（manganese peroxidase，MnP）。本研究从一株名为毛栓菌（Trametes hirsuta）OK271075的热带白腐真菌中，成功获得了部分纯化的漆酶-锰过氧化物酶复合酶制剂。分别为两种酶添加对应介体后，黑色素降解效率得到提升，这证实了漆酶与锰过氧化物酶可协同催化黑色素降解。当以TEMPO（0.2 mM）与硫酸锰-过氧化氢体系（0.75 mM、0.2 mM）作为介体时，黑色素最高降解率可达42%，较无介体处理组提升了20%。采用对应酶的特异性介体可获得更高的降解速率，这表明两种酶具备协同效应，可同时用于黑色素降解。傅里叶变换红外光谱（FTIR）与场发射扫描电子显微镜（FESEM）分析结果显示，酶处理组与未处理组黑色素的结构存在显著差异：经酶攻击后，黑色素颗粒发生破裂与剥落。热解气相色谱-质谱联用（Pyrolysis-GCMS）分析结果表明，酶处理组黑色素中酚类、环氧化物、酮类与羧酸类化合物的含量显著高于未处理组。本研究结果证实了新分离的毛栓菌（T. hirsuta）在生物技术领域的新型酶应用潜力，尤其可用于降解黑色素以制备天然美白化妆品。