Selenium (Se) plays a critical role in diverse biological processes and is widely used across manufacturing industries. However, the contamination of Se oxyanions also poses a major public health concern. Microbial transformation is a promising approach to detoxify Se oxyanions and produce elemental selenium nanoparticles (SeNPs) with versatile industrial potential. Yeast-like fungi are an important group of environmental microorganisms, but their mechanisms for Se oxyanions reduction remain unknown. In this study, we found that I15 can reduce 1.0 mM selenite by over 90% within 48 h and efficiently form intracellular or extracellular spherical SeNPs. Metabolomic and proteomic analyses disclosed that I15 evolves a complicated selenite reduction mechanism involving multiple metabolic pathways, including the glutathione/glutathione reductase pathway, the thioredoxin/thioredoxin reductase pathway, the siderophore-mediated pathway, and multiple oxidoreductase-mediated pathways. This study provides the first report on the mechanism of selenite reduction and SeNPs biogenesis in yeast-like fungi and paves an alternative avenue for the bioremediation of selenite contamination and the production of functional organic selenium compounds.

中文翻译：

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酵母样真菌 Aureobasidium melanogenum I15 中亚硒酸盐还原和元素硒纳米颗粒生物发生的多途径介导机制

硒 (Se) 在多种生物过程中发挥着关键作用，并广泛应用于制造业。然而，硒氧阴离子的污染也造成了重大的公共卫生问题。微生物转化是一种很有前途的方法，可以解毒硒氧阴离子并生产具有多种工业潜力的元素硒纳米颗粒（SeNP）。酵母类真菌是一类重要的环境微生物，但其还原硒氧阴离子的机制仍不清楚。在这项研究中，我们发现I15可以在48小时内将1.0 mM亚硒酸盐还原超过90%，并有效地形成细胞内或细胞外球形SeNPs。代谢组学和蛋白质组学分析表明，I15进化出复杂的亚硒酸盐还原机制，涉及多种代谢途径，包括谷胱甘肽/谷胱甘肽还原酶途径、硫氧还蛋白/硫氧还蛋白还原酶途径、铁载体介导的途径和多种氧化还原酶介导的途径。这项研究首次报道了类酵母真菌中亚硒酸盐还原和 SeNPs 生物合成的机制，并为亚硒酸盐污染的生物修复和功能性有机硒化合物的生产开辟了一条替代途径。