Microbial dissolution of crystalline mercury sulfide via cysteine secretion

IF 5 1区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Geochimica et Cosmochimica Acta Pub Date : 2025-08-23 DOI:10.1016/j.gca.2025.08.032

Qingyi Cao, Junyi Liu, Jicheng Xia, Jen-How Huang, Susan Glasauer, Haiyan Hu, Xinbin Feng

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引用次数: 0

Abstract

Mineral-associated mercury (Hg), predominantly as mercury sulfide (HgS), represents the largest environmental Hg reservoir and is typically considered immobile and inert. Here, we reveal a novel microbe-mediated mechanism for the bioleaching of crystalline HgS via cysteine secreted by microorganisms. Hg-resistant bacterial strains Arthrobacter sp. WS-B1, Massilia sp. WS-B3, and Serratia sp. WS-B5, isolated from Wanshan mining soils in China, were found to secrete cysteine, which promotes the disintegration of crystalline HgS into HgS nanoparticles (HgSNPs), dissolved Hg, and ultimately volatile Hg(0). Utilizing transmission electron microscopy with energy-dispersive X-ray spectroscopy, HgS breakdown was evidenced through the detection of HgSNPs and a broadened Hg:S ratio range from 1.08 ± 0.05 to 0.33–1.58. Time-of-flight secondary ion mass spectrometry analysis revealed the co-localisation of C3H7NO2S and Hg, indicating Hg–cysteine complexation. These complexes inhibited Hg precipitation, maintaining its bioavailability for crops, while also enabling photoreduction via ligand-to-metal charge transfer upon irradiation to detoxify soil Hg. This study sheds light on the microbial transformation of crystalline HgS, the formation pathways of HgSNPs in nature, and the enhanced bioavailability of Hg previously considered inert

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微生物通过半胱氨酸分泌溶解结晶硫化汞

矿物伴生汞（Hg），主要是硫化汞（HgS），是最大的环境汞储集层，通常被认为是不可移动和惰性的。在这里，我们揭示了一种新的微生物介导的机制，通过微生物分泌的半胱氨酸来浸出结晶HgS。从中国万山矿区土壤中分离出的抗汞菌株节杆菌sp. WS-B1、Massilia sp. WS-B3和Serratia sp. WS-B5分泌半胱氨酸，促进晶体汞分解成汞纳米颗粒（hgsnp）、溶解汞和最终挥发汞(0)。利用透射电子显微镜和能量色散x射线能谱，通过检测HgSNPs和扩大的Hg:S比值范围从1.08 ± 0.05到0.33-1.58，证明了HgS击穿。飞行时间二次离子质谱分析显示C3H7NO2S和Hg共定位，表明Hg -半胱氨酸络合。这些配合物抑制了汞的沉淀，维持了其对作物的生物利用度，同时在照射下通过配体到金属的电荷转移实现光还原，从而对土壤汞进行解毒。本研究揭示了结晶Hg的微生物转化、自然界中HgSNPs的形成途径，以及以前认为是惰性的Hg的生物利用度增强

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来源期刊

Geochimica et Cosmochimica Acta 地学-地球化学与地球物理

CiteScore

9.60

自引率

14.00%

发文量

437

审稿时长

6 months

期刊介绍： Geochimica et Cosmochimica Acta publishes research papers in a wide range of subjects in terrestrial geochemistry, meteoritics, and planetary geochemistry. The scope of the journal includes: 1). Physical chemistry of gases, aqueous solutions, glasses, and crystalline solids 2). Igneous and metamorphic petrology 3). Chemical processes in the atmosphere, hydrosphere, biosphere, and lithosphere of the Earth 4). Organic geochemistry 5). Isotope geochemistry 6). Meteoritics and meteorite impacts 7). Lunar science; and 8). Planetary geochemistry.