天然黑色素是一种具有广阔医药应用前景的生物聚合物,食物,化妆品,环境保护,农业,等等。微生物发酵是生产黑色素的重要而有效的途径。在这项研究中,黑原梭子花,被称为具有细胞多态性的黑色酵母,用于生产黑色素。基于在寡营养胁迫下黑原乳分泌黑色素的特性,一种只含有葡萄糖的简单培养基,MgSO4·7H2O,和KCl被构造用于生产黑色素。在没有pH控制的情况下发酵20天后获得6.64±0.22g/L的黑色素滴度。记录黑色素A在黑色素产生过程中的细胞形态变化,结果表明,衣原体孢子可能是黑色素合成最有利的细胞形态。然后,开发了具有细胞形态分析的不同发酵策略,以进一步提高5-L发酵罐中黑色素的产量。结果表明,采用pH控制的发酵策略,黑色素的最大滴度达到18.50g/L,铵盐添加,和H2O2刺激,比没有pH控制的策略增加了178.6%。此外,从发酵液中获得的黑色素被表征为含有吲哚结构的真黑素。本研究为黑色素的工业化生产提供了一种潜在可行的发酵策略。
Natural melanin is a biopolymer with wide application prospects in medicine, food, cosmetics, environmental protection, agriculture, and so on. Microbial fermentation is an important and effective way to produce melanin. In this study,
Aureobasidium melanogenum, known as black yeast with cellular pleomorphism, was used for the production of melanin. Based on the characteristic of A. melanogenum secreting melanin under oligotrophic stress, a simple medium containing only glucose, MgSO4·7H2O, and KCl was constructed for the production of melanin. The melanin titer of 6.64 ± 0.22 g/L was obtained after 20 days of fermentation without pH control. The cell morphological changes of A. melanogenum during the production of melanin were recorded, and the results showed that chlamydospore might be the most favorable cell morphology for melanin synthesis. Then, different fermentation strategies with cell morphology analysis were developed to further improve the production of melanin in a 5-L fermenter. Results showed that the maximum titer of melanin reached 18.50 g/L by using the fermentation strategy integrating pH control, ammonium salt addition, and H2O2 stimulation, which increased by 178.6% than that of the strategy without pH control. Furthermore, the melanin obtained from the fermentation broth was characterized as eumelanin containing an indole structure. This study provided a potentially feasible fermentation strategy for the industrial production of melanin.