Restaino Odile Francesca, Kordjazi Talayeh, Tancredi Francesco, Manini Paola, Lanzillo Fabiana, Raganati Francesca, Marzocchella Antonio, Porta Raffaele, Mariniello Loredana
Department of Chemical Sciences, Università degli Studi di Napoli Federico II, Monte sant'Angelo Campus, Via Cintia 4, 80126 Naples, Italy.
Department of Chemical, Materials and Production Engineering, Università degli Studi di Napoli Federico II, P. le V. Tecchio 80, 80125 Naples, Italy.
Int J Mol Sci. 2025 Jan 6;26(1):416. doi: 10.3390/ijms26010416.
As Streptomycetes might produce melanin to survive in stressful environmental conditions, like under metal exposure, supplementing metal ions to the growth medium could be a wise strategy for boosting the production of the pigment. The aim of this study was to test, for the first time, the possibility of boosting DSM40314 melanin biosynthesis by adding to the growth medium singularly or, at the same time, different concentrations (1.0, 1.5, and 2.0 g∙L) of CuSO or/and Fe(SO). A maximum melanin production of 4.0 ± 0.1 g·L was obtained in shake flasks with a 2.0 g∙L coupled addition of the two metals, while the extracellular tyrosinase activities ranged values between 5.4 and 11.6 ± 0.1 U·L. The pigments produced in different conditions were precipitated from the broth supernatants under acidic conditions, purified, and characterized by UV-VIS, FT-IR, and NMR analyses that determined structures like eumelanin pigments. Fermentation experiments in stirred tank reactors allowed to scale up the process in more controlled conditions, further boosting the pigment production up to 4.9 ± 0.1 g·L, with an increase of about 22.0% compared to the results obtained in shake flasks.
由于链霉菌可能会产生黑色素以在压力环境条件下生存,比如在金属暴露的情况下,向生长培养基中添加金属离子可能是提高色素产量的明智策略。本研究的目的是首次测试通过向生长培养基中单独添加或同时添加不同浓度(1.0、1.5和2.0 g∙L)的硫酸铜或/和硫酸铁来提高DSM40314黑色素生物合成的可能性。在摇瓶中,两种金属以2.0 g∙L的浓度联合添加时,黑色素的最大产量为4.0 ± 0.1 g·L,而细胞外酪氨酸酶活性范围在5.4至11.6 ± 0.1 U·L之间。在不同条件下产生的色素在酸性条件下从肉汤上清液中沉淀出来,进行纯化,并通过紫外可见光谱、傅里叶变换红外光谱和核磁共振分析进行表征,这些分析确定了类似真黑素色素的结构。在搅拌罐反应器中进行的发酵实验能够在更可控的条件下扩大生产规模,进一步将色素产量提高至4.9 ± 0.1 g·L,与在摇瓶中获得的结果相比增加了约22.0%。