Molybdenum (Mo) is essential for many enzymes but is often sequestered within minerals, rendering it not readily bioavailable. Metallophores, metabolites secreted by microorganisms and plants, promote mineral dissolution to increase the metal bioavailability. However, interactions between metallophores and Mo-bearing minerals remain unclear. In this study, catecholate protochelin and hydroxamate desferrioxamine B (DFOB) were utilized to examine their effects on dissolution of the common Mo-bearing mineral, molybdenite (MoS₂), under both oxic and anoxic conditions. Protochelin promoted molybdenite dissolution under oxic conditions, with the formation of MoO₃ on the surface and Mo-siderophore complexes in solution. This was attributed to air-oxidation of both molybdenite and protochelin, as evidenced by lack of dissolution under anoxic conditions but enhanced dissolution by either preoxidized protochelin or preoxidized molybdenite. Liquid chromatography–mass spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry analyses revealed degradation of protochelin and adsorptions of its byproducts on molybdenite surface to promote dissolution. Conversely, DFOB inhibited molybdenite dissolution under both oxic and anoxic conditions, likely attributed to surface adsorption of DFOB and its weak complexation with Mo(VI) at the circumneutral pH. This work highlights the need to consider the balance between promoting and inhibitory effects of different metallophores on Mo-mineral dissolution.

中文翻译：

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儿茶酚酸盐和异羟肟酸盐铁载体对辉钼酸盐溶解的对比效果


钼 （Mo） 对许多酶来说是必需的，但通常被封存在矿物质中，使其不易被生物利用。金属团是微生物和植物分泌的代谢物，可促进矿物溶解，提高金属的生物利用度。然而，金属团和含 Mo 矿物之间的相互作用仍不清楚。在这项研究中，儿茶酚酸盐原螯合物和异羟肟酸去铁胺 B （DFOB） 用于检查它们在含氧和缺氧条件下对常见含钼矿物辉钼矿 （MoS₂） 溶解的影响。原螯合蛋白在含氧条件下促进辉钼酸盐的溶解，在表面形成 MoO₃，在溶液中形成 Mo-铁载体复合物。这归因于辉钼矿和原钼酸盐的空气氧化，在缺氧条件下没有溶解，但预氧化原螘或预氧化辉钼酸盐增强了溶解。液相色谱-质谱、X 射线光电子能谱和飞行时间二次离子质谱分析揭示了原螘蛋白的降解及其副产物在辉钼石表面的吸附以促进溶解。相反，DFOB 在含氧和缺氧条件下都抑制了辉钼酸盐的溶解，这可能归因于 DFOB 的表面吸附及其在环中性 pH 值下与 Mo（VI） 的弱络合。这项工作强调了需要考虑不同金属团对 Mo 矿物溶解的促进和抑制作用之间的平衡。