Role Of Lanthanides Research Articles

Weathered granites and soils harbour microbes with lanthanide-dependent methylotrophic enzymes

BackgroundPrior to soil formation, phosphate liberated by rock weathering is often sequestered into highly insoluble lanthanide phosphate minerals. Dissolution of these minerals releases phosphate and lanthanides to the biosphere. Currently, the microorganisms involved in phosphate mineral dissolution and the role of lanthanides in microbial metabolism are poorly understood.ResultsAlthough there have been many studies of soil microbiology, very little research has investigated microbiomes of weathered rock. Here, we sampled weathered granite and associated soil to identify the zones of lanthanide phosphate mineral solubilisation and genomically define the organisms implicated in lanthanide utilisation. We reconstructed 136 genomes from 11 bacterial phyla and found that gene clusters implicated in lanthanide-based metabolism of methanol (primarily xoxF3 and xoxF5) are surprisingly common in microbial communities in moderately weathered granite. Notably, xoxF3 systems were found in Verrucomicrobia for the first time, and in Acidobacteria, Gemmatimonadetes and Alphaproteobacteria. The xoxF-containing gene clusters are shared by diverse Acidobacteria and Gemmatimonadetes, and include conserved hypothetical proteins and transporters not associated with the few well studied xoxF systems. Given that siderophore-like molecules that strongly bind lanthanides may be required to solubilise lanthanide phosphates, it is notable that candidate metallophore biosynthesis systems were most prevalent in bacteria in moderately weathered rock, especially in Acidobacteria with lanthanide-based systems.ConclusionsPhosphate mineral dissolution, putative metallophore production and lanthanide utilisation by enzymes involved in methanol oxidation linked to carbonic acid production co-occur in the zone of moderate granite weathering. In combination, these microbial processes likely accelerate the conversion of granitic rock to soil.

Enhanced Alkaline Hydrogen Evolution Reaction through Lanthanide-Modified Rhodium Intermetallic Catalysts.

Design of highly efficient electrocatalysts for alkaline hydrogen evolution reaction (HER) is of paramount importance for water electrolysis, but still a considerable challenge because of the slow HER kinetics in alkaline environments. Alloying is recognized as an effective strategy to enhance the catalytic properties. Lanthanides (Ln) are recognized as an electronic and structural regulator, attributed to their unique 4f electron behavior and the phenomenon known as lanthanide contraction. Here, a new class of Rh3Ln intermetallics (IMs) are synthesized using the sodium vapor reduction method. The alloying process induced an upshift of the d-band center and electron transfer from Ln to Rh, resulting in optimized adsorption and dissociation energies for H2O molecules. Consequently, Rh3Tb IMs exhibited outstanding HER activity in both alkaline environments and seawater, displaying an overpotential of only 19mV at 10mAcm-2 and a Tafel slope of 22.2mV dec-1. Remarkably, the current density of Rh3Tb IMs at 100mV overpotential is 8.6 and 5.7 times higher than that of Rh/C and commercial Pt/C, respectively. This work introduces a novel approach to the rational design of HER electrocatalysis and sheds light on the role of lanthanides in electrocatalyst systems.

Role of Lanthanides and Bilayer Fe2As2 in the Electronic Properties of RbLn2Fe4As4O2 (Ln = Gd, Tb, and Dy) Superconductors.

The superconducting transition temperatures (Tc) of RbGd2Fe4As4O2, RbTb2Fe4As4O2, and RbDy2Fe4As4O2 are 35 K, 34.7 K, and 34.3 K without doping, respectively. For the first time, we have studied the high-temperature nonmagnetic state and the low-temperature magnetic ground state of 12442 materials, RbTb2Fe4As4O2 and RbDy2Fe4As4O2, using first principles calculations and comparing them with RbGd2Fe4As4O2. We also performed a detailed study of the effects of lanthanides and bilayer Fe2As2. We predict that the ground state of RbLn2Fe4As4O2 (Ln = Gd, Tb, and Dy) is spin-density-wave-type, in-plane, striped antiferromagnets, and the magnetic moment around each Fe atom is about 2 μB. We also found that the structural differences caused by the simple ionic radius have little effect on the properties of these three materials. Different lanthanide elements themselves play a major role in the electronic properties of the materials. It can be confirmed that the effect of Gd on RbLn2Fe4As4O2 is indeed different from that of Tb and Dy, and the presence of Gd is more conducive to interlayer electron transfer. This means that Gd can transfer more electrons from the GdO layer to the FeAs layer compared to Tb and Dy. Therefore, RbGd2Fe4As4O2 has a stronger internal coupling strength of the bilayer Fe2As2 layer. This can explain why the Tc of RbGd2Fe4As4O2 is slightly higher than that of RbTb2Fe4As4O2 and RbDy2Fe4As4O2.

Fischer-Tropsch synthesis: Towards a highly-selective catalyst by lanthanide promotion under relevant CO2 syngas mixtures

The role of lanthanides as promoters on cobalt-based catalysts for Fischer-Tropsch synthesis was evaluated under relevant biomass-derived syngas mixtures. Cerium, lanthanum and a combination of them were impregnated on an industrial cobalt-based micro-catalyst. Lanthanide incorporation did not affect significantly the morphology of the catalyst, although it reduced the available surface cobalt. Catalytic tests revealed that both the presence of carbon dioxide in the feed and lanthanides in the catalyst led to similar outcomes; higher selectivity to long-chain hydrocarbons, at the expense of reactivity. Reaction experiments were well aligned with in-situ DRIFTS measurements, which evidenced the modification of the initial reaction mechanism, CO2 conversion and the presence of lower CO-cobalt coverages. This work reports two relevant findings for FTS development. Firstly, the presence of carbon dioxide is beneficial for long-chain hydrocarbon production. Secondly, the incorporation of lanthanides increases the production of gasoline, kerosene and diesel fractions.

Rare earth elements in soils of saline agrolandscapes of the Baraba plain

The total content of rare earth elements in the soil profile of saline agricultural landscapes catena of the Baraba plain within Novosibirsk region was studied. The total content of zirconium, yttrium, scandium, gallium, including lanthanides - cerium, lanthanum and ytterbium was determined. Rare earth elements are extremely poorly analyzed. At present, their influence on plants, organisms of animals and humans is being actively studied, although the maximum permissible and tentatively permissible concentrations for them have not yet been developed. The total content of rare earth elements, determined in the soils of the catena, depends on the granulometric composition and the degree of humus content of the soil horizons. It was revealed that in the studied soils they are mainly contained in the number of clarkes of the earth's crust, with the exception of lanthanum in the humus horizons, where its content is almost 1.5 times (44-48 mg/kg) higher than the clarke in the earth's crust (29 mg/kg), and ytterbium (10 times higher than the clarke). Along the soil profile, an insignificant movement of rare earth elements in both vertical and horizontal directions was noted, which indicates a low mobility of their compounds. Zirconium predominates in the profile of the studied soils from the group of rare earth elements. Its content in the humus horizons of soils of eluvial positions is within the clarke of the earth's crust; variations along the profile are insignificant. Ytterbium is contained in large quantities - from 1.89 to 4.05 mg/kg of soil, which is significantly higher than the clarke of the earth's crust (0.3 mg/kg of soil). The role of lanthanides in the soil -plant - animal - human system requires further in-depth study.

Systems Biology Meets Enzymology: Recent Insights into Communal Metabolism of Methane and the Role of Lanthanides.

In this review article, we cover the recent developments in understanding the principles and the mechanisms by which microbial communities participating in methane consumption in natural environmental niches are assembled, and the physiological and biochemical mechanisms and regulators that allow efficient carbon transfer within the communities. We first give a brief overview of methanotrophy. We then describe the recent evidence on non-random assembly of bacterial communities that utilize carbon from methane, based on stable isotope probing experiments as well as on results from natural community manipulations followed by metagenomic analysis. We follow up by highlighting results from synthetic methanotophic community manipulations identifying the importance of a lanthanide switch that regulates alternative methanol dehydrogenase enzymes in these communities. We further expand on the recently uncovered significance of lanthanides in methylotrophy and review data on the biochemical properties of representatives of two different clades of lanthanide-dependent enzymes. We also provide an overview of the occurrence and the distribution of the lanthanide-dependent alcohol dehydrogenases in the bacterial domain, these data strongly suggesting significance of these metals beyond methylotrophy.

Lanthanide-induced conformational change of methanol dehydrogenase involving coordination change of cofactor pyrroloquinoline quinone.

There is emerging interest in the role of lanthanides as cofactors for XoxF-type methanol dehydrogenase (MDH). Here, classical molecular dynamics simulations combined with fragment molecular orbital calculations were employed to rationalize the enzymatic activities of MDH (both XoxF- and MxaF-types) carrying different lanthanides. In XoxF-type MDH, lanthanide binding to cofactor pyrroloquinoline quinone was found to switch from tridentate to unidentate fashion as it switches from lighter to heavier lanthanides. This fact possibly plays a crucial role in the enzymatic activity exclusive to XoxF-type MDH incorporating lighter lanthanides.

Current Trends in Methylotrophy.

Methylotrophy is a field of study dealing with microorganisms capable of utilization of compounds devoid of carbon-carbon bonds (C1 compounds). In this review, we highlight several emerging trends in methylotrophy. First, we discuss the significance of the recent discovery of lanthanide-dependent alcohol dehydrogenases for understanding both the occurrence and the distribution of methylotrophy functions among bacteria, and then we discuss the newly appreciated role of lanthanides in biology. Next, we describe the detection of other methylotrophy pathways across novel bacterial taxa and insights into the evolution of methylotrophy. Further, data are presented on the occurrence and activity of aerobic methylotrophs in hypoxic and anoxic environments, questioning the prior assumptions on niche separation of aerobic and anaerobic methylotrophy. The concept of communal function in aerobic methane oxidation is also briefly discussed. Finally, we review recent research in engineering methylotrophs for biotechnological applications as well as recent progress in engineering synthetic methylotrophy.

Communal metabolism of methane and the rare Earth element switch.

Metabolism of methane is an important part of biogeochemical cycling of carbon. Methane is also a major contributor to climate change. A specialized group of microbes that consume methane, the methanotrophs, represent a natural filter preventing an even faster accumulation of methane in the atmosphere. Methanotrophy can proceed via both anaerobic and aerobic modes. The anaerobic methanotrophs, represented by both archaea and bacteria, all appear to be engaged in syntrophic interdependencies with other species, to overcome the energetic barriers of methane metabolism in the absence of oxygen. In contrast, aerobic methanotrophy can be carried out by pure cultures of bacteria. Nevertheless, a concept of communal function in aerobic methane oxidation has been gaining momentum, based on data from natural cooccurrence of specific functional guilds, and based on results from laboratory manipulations. The mechanistic details are still sparse on how and why the methanotrophs share their carbon with other species, and whether and what they gain in return. In this minireview we highlight recent studies that led to this new concept of community function in aerobic methane oxidation. We first describe the stable isotope probing experiments employing heavy carbon-labeled methane, tracing methane carbon consumption. We then follow up with analysis of data from microcosm community dynamics. We further discuss the role of a synthetic community approach in unraveling the principles of carbon flow and species cooperation in methane consumption. Finally, we touch on the role of lanthanides, which are rare Earth elements, previously thought to be biologically inert, in bacterial metabolism of methane.

Role of Lanthanides in the Traceability of the Milk Production Chain.

The traceability and authentication of milk were studied using trace and ultratrace elements as chemical markers. Among these variables, the group of lanthanides resulted in being particularly useful for this purpose as a result of their homogeneous distribution inside milk, which showed on the contrary to be intrinsically inhomogeneous from the elemental point of view. Using in this pilot study milk samples from a factory in Piedmont (Italy), we demonstrated that the distribution of lanthanides can be used as a fingerprint to put into relation the soil of the pasture land on which cows graze and the bottled milk produced in the factory. In fact, the distribution is maintained nearly unaltered along the production chain of milk, apart from the passage into the stomachs of the cows. Using the same variables, it was possible to discriminate between milk produced in the factory and milk samples taken from the large-scale retail trade.

Why methanol-oxidizing bacteria love lanthanides

Microbiology Although the lanthanide elements are not rare in Earth's crust, they are highly insoluble and difficult to separate. A biological role for these elements has therefore seemed implausible, but recent findings challenge this belief. In a Perspective, Skovran and Martinez-Gomez explain that some methanol-using bacteria contain an enzyme for methanol oxidation that is active only when lanthanide ions are present in the growth medium. Related enzymes have been found in other bacteria, suggesting a wider role of lanthanides in bacterial methanol oxidation. Further insight into the biological role of lanthanides may help toward developing bioremediation for lanthanide mining sites or allow the growth of new species in the lab. Science , this issue p. [862][1] [1]: /lookup/doi/10.1126/science.aaa9091