CAS Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistrygrid.454798.3, Chinese Academy of Sciences, Guangzhou, China.
CAS Center for Excellence in Deep Earth Science, Guangzhou, China.
Appl Environ Microbiol. 2022 Jul 12;88(13):e0063222. doi: 10.1128/aem.00632-22. Epub 2022 Jun 16.
Exogenic deposits are an important source of rare earth elements (REEs), especially heavy REEs (HREEs). It is generally accepted that microorganisms are able to dissolve minerals and mobilize elements in supergene environments. However, little is known about the roles of microorganisms in the formation of exogenic deposits such as regolith-hosted REE deposits that are of HREE enrichment and provide over 90% of global HREE demand. In this study, we characterized the microbial community composition and diversity along a complete weathering profile drilled from a regolith-hosted REE deposit in Southeastern China and report the striking contributions of microorganisms to the enrichment of REEs and fractionation between HREEs and light REEs (LREEs). Our results provide evidence that the variations in REE contents are correlated with microbial community along the profile. Both fungi and bacteria contributed to the accumulation of REEs, whereas bacteria played a key role in the fractionation between HREEs and LREEs. Taking advantage of bacteria strains isolated from the profile, Gram-positive bacteria affiliated with and preferentially adsorbed HREEs, and teichoic acids in the cell wall served as the main sites for HREE adsorption, leading to an enrichment of HREEs in the deposit. The present study provides the first database of microbial community in regolith-hosted REE deposits. These findings not only elucidate the crucial contribution of fungi and bacteria in the supergene REE mineralization but also provide insights into efficient utilization of mineral resources via a biological pathway. Understanding the role of microorganisms in the formation of regolith-hosted rare earth element (REE) deposits is beneficial for improving the metallogenic theory and deposit exploitation, given that such deposits absolutely exist in subtropical regions with strong microbial activities. Little is known of the microbial community composition and its contribution to REE mineralization in this kind of deposit. Using a combination of high-throughput sequencing, batch adsorption experiments, and spectroscopic characterization, the functional microorganisms contributing to REE enrichment and fractionation are disclosed. For bacteria, the surface carboxyl and phosphate groups are active sites for REE adsorption, while teichoic acids in the cell walls of G bacteria lead to REE fractionation. The above-mentioned findings not only unravel the importance of microorganisms in the formation of supergene REE deposits but also provide experimental evidence for the bioutilization of REE resources.
外生矿床是稀土元素（REEs）的重要来源，特别是重稀土元素（HREEs）。人们普遍认为，微生物能够在表生环境中溶解矿物质并使元素移动。然而，对于微生物在外生矿床形成中的作用知之甚少，例如风化壳型 REE 矿床，这些矿床富含 HREE，提供了全球 90%以上的 HREE 需求。在这项研究中，我们对中国东南部风化壳型 REE 矿床中一个完整风化剖面的微生物群落组成和多样性进行了表征，并报告了微生物对 REE 富集和 HREE 与轻稀土元素（LREEs）之间分馏的显著贡献。我们的结果提供了证据，表明 REE 含量的变化与沿剖面的微生物群落有关。真菌和细菌都有助于 REE 的积累，而细菌在 HREE 和 LREE 之间的分馏中起着关键作用。利用从剖面中分离出的细菌菌株，属于 和 的革兰氏阳性菌优先吸附 HREE，细胞壁中的磷壁酸作为 HREE 吸附的主要位点，导致矿床中 HREE 的富集。本研究提供了风化壳型 REE 矿床中微生物群落的第一个数据库。这些发现不仅阐明了真菌和细菌在表生 REE 矿化中的关键作用，而且为通过生物途径有效利用矿产资源提供了新的思路。 了解微生物在风化壳型稀土元素（REE）矿床形成中的作用，有助于完善成矿理论和矿床开采，因为在微生物活动强烈的亚热带地区，这种矿床确实存在。对于这种矿床中的微生物群落组成及其对 REE 矿化的贡献知之甚少。本研究采用高通量测序、批量吸附实验和光谱表征相结合的方法，揭示了促进 REE 富集和分馏的功能微生物。对于细菌，表面羧基和磷酸基团是 REE 吸附的活性位点，而 G 细菌细胞壁中的磷壁酸导致 REE 分馏。上述发现不仅揭示了微生物在表生 REE 矿床形成中的重要性，而且为 REE 资源的生物利用提供了实验证据。
