Colonization and bioweathering of monazite by Aspergillus niger: solubilization and precipitation of rare earth elements.

Xia Kang,Laszlo Csetenyi,Geoffrey Michael Gadd

doi:10.1111/1462-2920.15402

Xia Kang, Laszlo Csetenyi + Show 1 more

Open Access

https://doi.org/10.1111/1462-2920.15402

Copy DOI

Abstract

Geoactive fungi play a significant role in bioweathering of rock and mineral substrates. Monazite is a phosphate mineral containing the rare earth elements (REE) cerium, lanthanum and neodymium. Little is known about geomicrobial transformations of REE-bearing minerals which are also relevant to REE biorecovery from terrestrial and extra-terrestrial reserves. The geoactive soil fungus Aspergillus niger colonized monazite in solid and liquid growth media without any apparent growth inhibition. In a glucose-minerals salts medium, monazite enhanced growth and mycelium extensively covered rock particle surfaces, probably due to the provision of phosphate and essential trace metals. Teeth-like and pagoda-like etching patterns indicated monazite dissolution, with extensive precipitation of secondary oxalate minerals. Biomechanical forces ensued causing aggressive bioweathering effects by tunnelling, penetration and splitting of the ore particles. High amounts of oxalic acid (~46 mM) and moderate amounts of citric acid (~5 mM) were produced in liquid media containing 2% (wt./vol.) monazite, and REE and phosphate were released. Correlation analysis suggested that citric acid was more effective than oxalic acid in REE mobilization, although the higher concentration of oxalic acid also implied complexant activity, as well as the prime role in REE-oxalate precipitation.

Highlights

The activities of living organisms can lead to degradation, deterioration, erosion and weathering of both natural and synthetic materials (Mottershead et al, 2003; Gadd, 2010, 2017a; Ma et al, 2020)
Geoactive fungi play a significant role in bioweathering of rock and mineral substrates
Little is known about geomicrobial transformations of rare earth elements (REE)-bearing minerals which are relevant to REE biorecovery from terrestrial and extra-terrestrial reserves

Summary

Introduction

The activities of living organisms can lead to degradation, deterioration, erosion and weathering of both natural and synthetic materials (Mottershead et al, 2003; Gadd, 2010, 2017a; Ma et al, 2020). Fungal-induced rock and mineral bioweathering plays an important part in the lithological biogeochemical cycling of carbon, phosphorus and essential metal elements such as K, Ca and Mg (Hoffland et al, 2004). Common rock types such as granite, limestone, marble and sandstone are prone to colonization, biodeterioration and bioweathering by a wide range of lichenized, free-living, and microcolonial fungi, and bacteria (Staley et al, 1982; Wollenzien et al, 1995; Burford et al, 2003a, 2003b; Gadd, 2017a).

Objectives

Results

Discussion

Conclusion