Abstract In the present study, the mechanism of jarosite biosynthesis mediated by extracellular polymer substances (EPSs) of Purpureocillium lilacinum strain Y3 at gene level was investigated. Yellow-ocher jarosite minerals covered mycelia pellets entirely within 72h, corresponding to a reduction of Fe3+ of 70.9% in the biomineralization process induced by P. lilacinum Y3. The maximum biomass accumulation reached to 12.9 g/L in pure culture, 2.8 g/L with only 0.02M Fe3+ addition, and 6.4 g/L with both 0.02M Fe3+ and 0.1M K+ addition, respectively, indicating that jarosite biosynthesis largely alleviated the inhibition of Fe3+ to the fungal strain. Thereafter, the analysis of EPSs compositions suggested that protein content was affected more evidently than polysaccharides in the biomineralization system. Furthermore, real time quantitative PCR assays revealed that signal transduction genes and abundance of membrane transporters were activated quickly in responding to the stimulation of Fe3+ and fungus-mineral interactions. Then, the expression of adhesive proteins and extracellular proteins was highly up-regulated to facilitate the formation of jarosite minerals on the cell surface. Finally, X-ray photoelectron spectroscopy analysis supported that amine, carboxyl, phosphate groups present on the mycelia provided Fe3+ and K+ binding sites for biosynthesis of jarosite.

中文翻译：

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基于紫堇菜Y3胞外聚合物的潜在黄钾铁矾生物矿化机制探索

摘要 本研究从基因水平研究紫丁香菌株Y3胞外聚合物(EPSs)介导黄钾铁矾生物合成的机制。黄赭石矿物在 72 小时内完全覆盖菌丝体颗粒，对应于 P. lilacinum Y3 诱导的生物矿化过程中 Fe3+ 减少 70.9%。最大生物量积累在纯培养中达到 12.9 g/L，仅添加 0.02M Fe3+ 时为 2.8 g/L，添加 0.02M Fe3+ 和 0.1M K+ 时分别为 6.4 g/L，表明黄钾铁矾生物合成在很大程度上缓解了Fe3+ 对真菌菌株的抑制作用。此后，EPSs 组成的分析表明，在生物矿化系统中，蛋白质含量比多糖受到的影响更明显。此外，实时定量 PCR 分析表明，信号转导基因和大量膜转运蛋白在响应 Fe3+ 和真菌-矿物质相互作用的刺激时被迅速激活。然后，粘附蛋白和细胞外蛋白的表达被高度上调，以促进细胞表面黄钾铁矾矿物质的形成。最后，X 射线光电子能谱分析支持存在于菌丝体上的胺、羧基、磷酸基团为黄钾铁矾的生物合成提供了 Fe3+ 和 K+ 结合位点。粘附蛋白和细胞外蛋白的表达高度上调，以促进细胞表面黄钾铁矾矿物质的形成。最后，X 射线光电子能谱分析支持存在于菌丝体上的胺、羧基、磷酸基团为黄钾铁矾的生物合成提供了 Fe3+ 和 K+ 结合位点。粘附蛋白和细胞外蛋白的表达高度上调，以促进细胞表面黄钾铁矾矿物质的形成。最后，X 射线光电子能谱分析支持存在于菌丝体上的胺、羧基、磷酸基团为黄钾铁矾的生物合成提供了 Fe3+ 和 K+ 结合位点。