Abstract：
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 Aureobasidium melanogenum 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 A. melanogenum 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.
摘要：
硒（Se）在各种生物过程中起着至关重要的作用，并广泛用于制造业。然而,硒氧阴离子的污染也引起了重大的公共卫生问题。微生物转化是使Se氧阴离子解毒并生产具有多种工业潜力的元素硒纳米颗粒（SeNP）的有前途的方法。类酵母真菌是一类重要的环境微生物,但是它们还原硒氧阴离子的机制仍然未知。在这项研究中,我们发现，黑原金黄色葡萄球菌I15可以在48小时内将1.0mM亚硒酸盐减少90％以上，并有效形成细胞内或细胞外球形SeNPs。代谢组学和蛋白质组学分析显示，黑色素A.I15进化出复杂的亚硒酸盐减少机制，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。这项研究提供了有关酵母样真菌中亚硒酸盐还原和SeNPs生物发生机制的第一份报告，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铺平了道路。
