粗毛纤孔菌产胞外黑色素发酵条件优化及其抗氧化活性研究

为提高天然黑色素的产量，本研究通过探索碳氮源、转速、pH、温度等单因素对粗毛纤孔菌产黑色素的影响，并利用正交试验筛选产胞外黑色素的最适发酵培养基配方和发酵条件。结果表明，优化后的最佳发酵培养基配方为甘露醇20 g·L^-1、牛肉浸膏5 g·L^-1、碳氮比4∶1、维生素B₁ 10 mg·L^-1，最适发酵条件为发酵温度25℃、发酵初始pH值6、转速180 r·min^-1、发酵时间10 d。在此培养条件下，粗毛纤孔菌胞外黑色素(IHEM)含量高达3.29 g·L^-1，较优化前提高了17.32倍。IHEM体外化学抗氧化活性检测结果显示，IHEM具有良好的抗氧化活性，其对ABTS自由基的清除效果较佳，半最大效应浓度(EC₅₀)为0.019 mg·mL^-1。本研究结果为深层发酵高产黑色素的开发提供了技术支持。

Optimization of Fermentation Conditions for Extracellular Melanin Production From Inonotus hispidus and Its Antioxidant Activity

To improve the production of natural melanin， this study explored the effects of carbon and nitrogen sources， rotational speed， pH value and temperature on melanin production from Inonotus hispidus （Bull.） P. Karst.， and used orthogonal tests to select the most suitable fermentation medium formulation and fermentation conditions for extracellular melanin production. The results showed that the optimal fermentation medium formula after optimization was： mannitol 20 g·L^-1， beef extract 5 g·L^-1， carbon to nitrogen ratio（C/N）4∶1， vitamin B₁ 10 mg·L^-1. The optimal fermentation conditions were： temperature 25 ℃， initial fermentation pH 6， rotation speed 180 r·min^-1， and fermentation 10 days. Under these culture conditions， the content of extracellular melanin of Inonotus hispidus （IHEM） was as high as 3.29 g·L^-1， which was 17.32 times higher than that before optimization. The results of in vitro chemical antioxidant activity of IHEM showed that IHEM had good antioxidant activity， and the effect on ABTS radical scavenging was better， and the concentration for 50% of maximal effect （EC₅₀） was 0.019 mg·mL^-1. In conclusion， we explored the fermentation conditions for high production of extracellular melanin by Inonotus hispidus， which provided theoretical support for high melanin production by deep fermentation.