Tolerance of Rare-Earth Elements in Extremophile Fungus Umbelopsis isabellina from Polar Loparite Ore Tailings in Northwestern Russia

Abstract

In this study, extremophile fungal species isolated from pure loparite-containing sands and their tolerance/resistance to the lanthanides Ce and Nd were investigated. The loparite-containing sands were collected at the tailing dumps of an enterprise developing a unique polar deposit of niobium, tantalum and rare-earth elements (REEs) of the cerium group: the Lovozersky Mining and Processing Plant (MPP), located in the center of the Kola Peninsula (northwestern Russia). From the 15 fungal species found at the site, one of the most dominant isolates was identified by molecular analysis as the zygomycete fungus Umbelopsis isabellina (GenBank accession no. OQ165236). Fungal tolerance/resistance was evaluated using different concentrations of CeCl3 and NdCl3. Umbelopsis isabellina exhibited a higher degree of tolerance/resistance to cerium and neodymium than did the other dominant isolates (Aspergillus niveoglaucus, Geomyces vinaceus and Penicillium simplicissimum). The fungus began to be inhibited only after being exposed to 100 mg L−1 of NdCl3. The toxic effects of Ce were not observed in fungus growth until it was subjected to 500 mg∙L−1 of CeCl3. Moreover, only U. isabellina started to grow after extreme treatment with 1000 mg∙L−1 of CeCl3 one month after inoculation. This work indicates, for the first time, the potential of Umbelopsis isabellina to remove REEs from the loparite ore tailings, making it a suitable candidate for the development of bioleaching methods.

Hormesis and Low Toxic Effects of Three Lanthanides in Microfungi Isolated from Rare Earth Mining Waste in Northwestern Russia

“…The microfungal strains used in the present study were Aspergillus niveoglaucus OQ165229; Geomyces vinaceus OQ165231; Penicillium simplicissimum OQ165232; Pseudogymnoascus pannorum ; Umbelopsis isabellina OQ165236 isolated from the Loparite tailing dump of the Lovozersky Mining and Processing Plant (MPP) (67.9° N, 34.6° E) [ 26 , 38 ]. Another strain was Sydowia polyspora supplied by the Komarov Botanical Institute, Saint Petersburg, Russia.…”

“…Another strain was Sydowia polyspora supplied by the Komarov Botanical Institute, Saint Petersburg, Russia. The last two fungi are typical subarctic representatives [ 26 , 43 ].…”

“…For instance, La interacts significantly with erythrocytes and leukocytes, inhibiting its normal function and recovery [ 20 ]. Some studies have reported that REE at a low dose may have beneficial effects that are termed hormesis, and at a high dose, they may have harmful effects on the growth and development of plants [ 21 , 22 , 23 ], bacteria [ 24 ], microfungi [ 25 , 26 , 27 , 28 ], aquatic organisms [ 29 ] and animal models [ 30 , 31 ]. Despite the fact that hormesis has been a well-known phenomenon for a long time [ 32 , 33 , 34 ], there are few studies concerning the response of microorganisms, including fungi, to rare earths at hormetic doses [ 24 , 25 , 26 , 27 , 28 ].…”

“…Some studies have reported that REE at a low dose may have beneficial effects that are termed hormesis, and at a high dose, they may have harmful effects on the growth and development of plants [ 21 , 22 , 23 ], bacteria [ 24 ], microfungi [ 25 , 26 , 27 , 28 ], aquatic organisms [ 29 ] and animal models [ 30 , 31 ]. Despite the fact that hormesis has been a well-known phenomenon for a long time [ 32 , 33 , 34 ], there are few studies concerning the response of microorganisms, including fungi, to rare earths at hormetic doses [ 24 , 25 , 26 , 27 , 28 ]. Therefore, questions concerning toxic and favorable REE-associated effects are still important research subjects among scientists [ 1 , 6 , 14 , 15 , 35 ].…”

“…The average concentrations of REEs in the Kola loparite and apatite–nepheline ore tailings are 1150 mg/kg and 770 mg/kg, respectively; therefore, these mining wastes can become sources for the extraction of REEs [ 11 ]. Recent studies investigated the biological potential of some microfungi to recover REEs from the Kola loparite ore tailings [ 26 , 38 ].…”