Monazite is a naturally-occurring lanthanide (Ln) phosphate mineral [Lnx (PO4 )y ] and is the main industrial source of the rare earth elements (REE), cerium and lanthanum. Endeavours to ensure the security of supply of elements critical to modern technologies view bioprocessing as a promising alternative or adjunct to new methods of element recovery. However, relatively little is known about microbial interactions with REE. Fungi are important geoactive agents in the terrestrial environment and well known for properties of mineral transformations, particularly phosphate solubilization. Accordingly, this research examined the capability of a ubiquitous geoactive soil fungus, Aspergillus niger, to affect the mobility of REE in monazite and identify possible mechanisms for biorecovery. It was found that A. niger could grow in the presence of monazite and mediated the formation of secondary Ce and La-containing biominerals with distinct morphologies including thin sheets, orthorhombic tablets, acicular needles, and rosette aggregates which were identified as cerium oxalate decahydrate (Ce2 (C2 O4 )3 ·10H2 O) and lanthanum oxalate decahydrate (La2 (C2 O4 )3 ·10H2 O). In order to identify a means for biorecovery of REE via oxalate precipitation the bioleaching and bioprecipitation potential of biomass-free spent culture supernatants was investigated. Although such indirect bioleaching of REE was low from the monazite with maximal lanthanide release reaching >40 mg L-1 , leached REE were efficiently precipitated as Ce and La oxalates of high purity, and did not contain Nd, Pr and Ba, present in the original monazite. Geochemical modelling of the speciation of oxalates and phosphates in the reaction system confirmed that pure Ln oxalates can be formed under a wide range of chemical conditions. These findings provide fundamental knowledge about the interactions with and biotransformation of REE present in a natural mineral resource, and indicate the potential of oxalate bioprecipitation as a means for efficient biorecovery of REE from solution. This article is protected by copyright. All rights reserved.

中文翻译：

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黑曲霉将独居石转化为含Ce和La的草酸盐。

独居石是天然存在的镧系元素（Ln）磷酸盐矿物[Lnx（PO4）y]，并且是稀土元素（REE），铈和镧的主要工业来源。为确保对现代技术至关重要的元素供应的安全而进行的努力将生物加工视为元素回收新方法的有前途的替代方法或辅助手段。但是，关于微生物与REE相互作用的信息知之甚少。真菌在陆地环境中是重要的地质活性剂，并且因矿物质转化（尤其是磷酸盐溶解）的特性而闻名。因此，这项研究检验了普遍存在的土壤活性土壤真菌黑曲霉对独居石中REE的迁移能力的影响，并确定了生物回收的可能机制。发现A。尼日尔可以在独居石存在下生长，并介导具有不同形态的次级Ce和La的生物矿物的形成，包括薄片，正交晶片，针状针和玫瑰花结聚集物，其被鉴定为草酸铈十水合物（Ce2（C2 O4）3） ·10H2 O）和草酸镧十水合物（La2（C2 O4）3·10H2 O）。为了确定通过草酸盐沉淀生物回收REE的方法，研究了无生物质的废培养上清液的生物浸出和生物沉淀潜力。尽管从独居石中进行的这种稀土的间接生物浸出率低，最大镧系元素释放量达到> 40 mg L-1，但作为高纯度的Ce和La草酸盐，且不含有Nd，Pr和Ba，浸出的REE被有效沉淀。原始独居石。对反应体系中草酸盐和磷酸盐的形态进行地球化学建模证实，纯草酸Ln可以在多种化学条件下形成。这些发现提供了与天然矿产资源中存在的稀土元素相互作用和生物转化的基础知识，并表明了草酸盐生物沉淀作为从溶液中高效生物回收稀土元素的潜力。本文受版权保护。版权所有。并指出草酸盐生物沉淀作为从溶液中有效生物回收REE的方法的潜力。本文受版权保护。版权所有。并指出草酸盐生物沉淀作为从溶液中有效生物回收REE的方法的潜力。本文受版权保护。版权所有。