Biogenic Metal Research Articles

Biogenic metal nanoparticles with microbes and their applications in water treatment: a review.

Due to their unique characteristics, nanomaterials are widely used in many applications including water treatment. They are usually synthesized via physiochemical methods mostly involving toxic chemicals and extreme conditions. Recently, the biogenic metal nanoparticles (Bio-Me-NPs) with microbes have triggered extensive exploration. Besides their environmental-friendly raw materials and ambient biosynthesis conditions, Bio-Me-NPs also exhibit the unique surface properties and crystalline structures, which could eliminate various contaminants from water. Recent findings in the synthesis, morphology, composition, and structure of Bio-Me-NPs have been reviewed here, with an emphasis on the metal elements of Fe, Mn, Pd, Au, and Ag and their composites which are synthesized by bacteria, fungi, and algae. Furthermore, the mechanisms of eliminating organic and inorganic contaminants with Bio-Me-NPs are elucidated in detail, including adsorption, oxidation, reduction, and catalysis. The scale-up applicability of Bio-Me-NPs is also discussed.

Множинні ефекти хронічного низькодозового впливу кадмію на печінку, остеогенез та гемопоез тварин і людини

Cadmium salts are among the TOP-20 of the most dangerous compounds for animals in terms of toxicity. At the same time, today there is a paradigm shift in the studies of cadmium effects: in contrast to the acute effects of intoxication, more importance and practical relevance is attained by studying the continued chronic exposure to small cadmium doses (Chronic Low Cd Exposure) which can take place in real environmental conditions of industrially polluted regions and already impacts about 10% of the world population. While the early changes in kidneys and marker parameters of the urinary system under the action of cadmium are being studied quite actively, cadmium effects on other organs and systems in the body are insufficiently investigated. The purpose of the study was to analyse the multiple effects of cadmium on liver function, osteogenesis, haematopoiesis, and haemostasis in animals and humans. Protective mechanisms that reduce cadmium accumulation in hepatocytes compared to renal cells, in particular, the role of cellular transporters of biogenic metal ions (Fe2+, Zn2+, Mn2+, Cu2+), are systematized. Results and discussion. Cadmium mostly uses divalent metal transporter 1 and Zrt/Irt-like transporters, such as ZIP8 and ZIP14. Given the role of liver in the chelation and deposition of cadmium in the form of complexes with metallothioneins and glutathione, the significant potential of chelating and antioxidant hepatoprotectants to reduce negative effects is suggested. The role of exogenous chemical chelators and antioxidants in detoxifying cadmium is supported by the studies of other cadmium-binding molecules (glutathione, polyphenols, anthocyanins). Both direct effects of cadmium on the osteogenesis and calcium metabolism, and indirect effects on osteoblasts and osteoclasts are considered. In particular, current data on cadmium role in the development of endemic disease Itai-Itai in Japan is discussed. Notably, cadmium effect in children has a special hazards and long-term consequences. Data on cadmium role in interfering Ca2+ metabolism, particularly its effects on epithelial calcium channels (TRPV5) and Na-phosphate co-transporters (SLC34A1) are summarized. Conclusion. Current data suggest that chronic effects of cadmium in ultra-low concentrations upon the osteogenesis are even more evident than in renal system. A review of current data on cadmium effects upon the hematopoietic system in animal models is presented. The earliest studies found relation between cadmium and haemoglobin decrease, which could be mediated by interfering with intracellular Fe traffic, and effects on erythropoietin synthesis. Cadmium affected haemostasis and increased platelet aggregation. Animal studies suggest that chronic cadmium toxicity leads to hypercoagulation and increases the risks of thrombosis. Based on the summarized data, it is concluded that the investigating cadmium effects on hematopoiesis and hemostasis is a promising area for further studies of chronic low-dose cadmium exposure

Calcium in Signaling: Its Specificity and Vulnerabilities toward Biogenic and Abiogenic Metal Ions.

Divalent calcium ion (Ca2+) plays an indispensable role as a second messenger in a myriad of signal transduction processes. Of utmost importance for the faultless functioning of calcium-modulated signaling proteins is their binding selectivity of the native metal cation over rival biogenic/abiogenic metal ion contenders in the intra/extracellular fluids. In this Perspective, we summarize recent findings on the competition between the cognate Ca2+ and other biogenic or abiogenic divalent cations for binding to Ca2+-signaling proteins or organic cofactors. We describe the competition between the two most abundant intracellular biogenic metal ions (Mg2+ and Ca2+) for Ca2+-binding sites in signaling proteins, followed by the rivalry between native Ca2+ and "therapeutic" Li+ as well as "toxic" Pb2+. We delineate the key factors governing the rivalry between the native and non-native cations in proteins and highlight key implications for the biological performance of the respective proteins/organic cofactors.

New frontiers in the plant extract mediated biosynthesis of copper oxide (CuO) nanoparticles and their potential applications: A review

Copper oxide nanoparticles (CuO NPs) are one of the most widely used nanomaterials nowadays. CuO NPs have numerous applications in biological processes, medicine, energy devices, environmental remediation, and industrial fields from nanotechnology. With the increasing concern about the energy crisis and the challenges of chemical and physical approaches for preparing metal NPs, attempts to develop modern alternative chemistry have gotten much attention. Biological approaches that do not produce toxic waste and therefore do not require purification processes have been the subject of numerous studies. Plants may be extremely useful in the study of biogenic metal NP synthesis. This review aims to shed more light on the interactions between plant extracts and CuO NP synthesis. The use of living plants for CuO NPs biosynthesis is a cost-effective and environmentally friendly process. To date, the findings have revealed many aspects of plant physiology and their relationships to the synthesis of NPs. The current state of the art and potential challenges in the green synthesis of CuO NPs are described in this paper. This study found a recent increase in the green synthesis of CuO NPs using various plant extracts. As a result, a thorough explanation of green synthesis and stabilizing agents for CuO NPs made from these green sources is given. Additionally, the multifunctional applications of CuO NPs synthesized with various plant extracts in environmental remediation, sensing, catalytic reduction, photocatalysis, diverse biological activities, energy storage, and several organic transformations such as reduction, coupling, and multicomponent reactions were carefully reviewed. We expect that this review could serve as a useful guide for readers with a general interest in the plant extract mediated biosynthesis of CuO NPs and their potential applications.

Sustainable and green trends in using plant extracts for the synthesis of biogenic metal nanoparticles toward environmental and pharmaceutical advances: A review

Conventionally utilized physical and chemical routes for constructing nanoparticles are not eco-friendly. They are associated with many shortcomings like the requirement of specially designed equipment, templates, extremely high temperature, and pressure. Biosynthesis seems to be drawn unequivocal attention owing to its upsurge of applications in different fields like; energy, nutrition, pharmaceutical, and medicinal sciences. To harness the biological sources, the present review describes an environment-friendly route to generate biogenic nanoparticles from the natural plant extracts and the followed mechanisms for their synthesis, growth, and stabilization. The present review summarizes the recent trends involved in the photosynthesis of metallic nanoparticles and their effective use in controlling malaria, hepatitis, cancer, like various endemic diseases. Also, various characterization approaches, such as UV–visible spectrophotometry, Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy, are discussed here examine the properties of as-fabricated nanoparticles. Various plant parts like leaves, stems, barks, fruit, and flowers are rich in flavonoids, phenols, steroids, terpenoids, enzymes, and alkaloids, thereby playing an essential role in reducing metal ions that generate metallic nanoparticles. Herein, the uniqueness of phytofabricated nanoparticles along with their distinctive antibacterial, antioxidant, cytotoxic, and drug delivery properties are featured. Lastly, this work highlights the various challenges and future perspectives to further synthesize biogenic metal nanoparticles toward environmental and pharmaceutical advances in the coming years.

Bacterial metal nanoparticles to develop new weapons against bacterial biofilms and infections.

The widespread use of antibiotics has resulted in the outbreak and spread of antibiotic-resistant pathogens. Bacterial antibiotic resistance may develop at cellular and community levels. In the latter case, it is based on tolerance which implicates the shift from a free-living form of life (i.e., planktonic) to a sessile multi-stratified community (i.e., biofilm). Metal nanoparticles (MNPs) have been shown to be promising candidates as antimicrobial agents. MNPs are able to interact with and penetrate bacterial biofilms, thus, resulting effective antibiofilm compounds. Another interesting aspect is the possibility of using plants, fungi, yeasts, and bacteria to obtain biogenic MNPs (BMNP). Bacteria are able to grow in presence of many different toxic heavy metal ions thanks to different metal resistance gene clusters that allow a variety of biochemical counters (formation of harmless complexes, efflux, precipitation, reduction, etc.). The formation of BMNPs by bacterial cells could be, in most cases, just a consequence of metal detoxification mechanisms. This review focuses on BMNPs from bacterial origin that may represent a good source of compounds with a broad spectrum of activity against common Gram-positive and Gram-negative pathogens and bacterial biofilms thereof. In particular, the state of art on BMNP synthesis by bacteria is presented and potential applications in the fight against biofilm-associated infections and resistant pathogens are highlighted. In addition, critical aspects on BMNP bacterial synthesis and utilization are commented.Key points• New antimicrobials to fight antibiotic-resistant pathogens are urgently needed.• Biogenic metal nanoparticles can efficiently hit biofilm-forming pathogens.• Metal-nanoparticle composition could confer specific antibiofilm activity.

Medicinal Plants and Biogenic Metal Oxide Nanoparticles: A Paradigm Shift to Treat Alzheimer’s Disease

Alzheimer’s disease (AD) is the most prevalent form of dementia. Improving the amount of acetylcholine in the brain is an efficient way to treat the illness. The global incidence of dementia is estimated to be as high as 50 million, and it is expected to increase every 20 years until 2040, resulting in a costly burden of disease. Early-life risk factors for pathology include genes, chromosomal abnormalities, head injury, insulin resistance, and inflammation. Potentially modifiable risk factors including obesity, diabetes, hypertension, and smoking are associated with Alzheimer’s disease (AD) and represent promising targets for intervention. The drugs currently being used to manage AD have various drawbacks. The chemical inhibition of cholinesterase enzymes is an effective technique for treating signal related neuropathology, and possible sources of compounds with these properties are natural products and biogenic metal oxide nanoparticles. There is a potential source of AChE and BChE inhibitors in the abundance of plants in nature, and natural goods appear to offer useful medications and templates for the development of other compounds. This dissertation represents a review of the literature on species of medicinal plants and nanomaterial related plants tested for their inhibitory action of AChE and BChE. Plant species and the plant-mediated metal oxide nanoparticles referred to are possible cholinesterase inhibitors and can assist researchers in their study of natural products that may be beneficial in the treatment of AD.

Biogenic ZnO Nanoparticles Synthesized Using a Novel Plant Extract: Application to Enhance Physiological and Biochemical Traits in Maize.

The need to increase crop productivity and resistance directs interest in nanotechnology. Indeed, biogenic metal oxide nanoparticles can promote beneficial effects in plants, while their synthesis avoids the environmental impacts of conventional synthetic procedures. In this context, this research aimed to synthesize biogenic zinc oxide nanoparticles (ZnO-NPs) using, for the first time, an extract of a wild and spontaneous aquatic species, Lemna minor (duckweed). The effectiveness of this biogenic synthesis was evidenced for comparison with non-biogenic ZnO-NPs (obtained without using the plant extract), which have been synthesized in this research. XRD (X-ray diffraction), FE-SEM (field emission gun electron scanning microscopy), EDX (energy dispersive x-ray spectroscopy), TEM (transmission electron microscope) and UV-vis (ultraviolet-visible spectrophotometry) showed the biogenic approach effectiveness. The duckweed extract was subjected to UHPLC-ESI/QTOF-MS (ultra high-pressure liquid chromatography quadrupole time of flight mass spectrometry) phenolic profiling. This untargeted characterization highlighted a high and chemically diverse content in the duckweed extract of compounds potentially implicated in nanoparticulation. From an application standpoint, the effect of biogenic nanoparticles was investigated on some traits of maize subjected to seed priming with a wide range of biogenic ZnO-NPs concentrations. Inductive effects on the shoot and root biomass development were ascertained concerning the applied dosage. Furthermore, the biogenic ZnO-NPs stimulated the content of chlorophylls, carotenoids, and anthocyanin. Finally, the study of malondialdehyde content (MDA) as a marker of the oxidative status further highlighted the beneficial and positive action of the biogenic ZnO-NPs on maize.

Oxygen Generation via Water Splitting by a Novel Biogenic Metal Ion-Binding Compound.

ABSTRACTMethanobactins (MBs) are small (<1,300-Da) posttranslationally modified copper-binding peptides and represent the extracellular component of a copper acquisition system in some methanotrophs. Interestingly, MBs can bind a range of metal ions, with some being reduced after binding, e.g., Cu2+ reduced to Cu+. Other metal ions, however, are bound but not reduced, e.g., K+. The source of electrons for selective metal ion reduction has been speculated to be water but never empirically shown. Here, using H218O, we show that when MBs from Methylocystis sp. strain SB2 (MB-SB2) and Methylosinus trichosporium OB3b (MB-OB3) were incubated in the presence of either Au3+, Cu2, or Ag+, 18,18O2 and free protons were released. No 18,18O2 production was observed in the presence of either MB-SB2 or MB-OB3b alone, gold alone, copper alone, or silver alone or when K+ or Mo2+ was incubated with MB-SB2. In contrast to MB-OB3b, MB-SB2 binds Fe3+ with an N2S2 coordination and will also reduce Fe3+ to Fe2+. Iron reduction was also found to be coupled to the oxidation of 2H2O and the generation of O2. MB-SB2 will also couple Hg2+, Ni2+, and Co2+ reduction to the oxidation of 2H2O and the generation of O2, but MB-OB3b will not, ostensibly as MB-OB3b binds but does not reduce these metal ions. To determine if the O2 generated during metal ion reduction by MB could be coupled to methane oxidation, 13CH4 oxidation by Methylosinus trichosporium OB3b was monitored under anoxic conditions. The results demonstrate that O2 generation from metal ion reduction by MB-OB3b can support methane oxidation.IMPORTANCE The discovery that MB will couple the oxidation of H2O to metal ion reduction and the release of O2 suggests that methanotrophs expressing MB may be able to maintain their activity under hypoxic/anoxic conditions through the “self-generation” of dioxygen required for the initial oxidation of methane to methanol. Such an ability may be an important factor in enabling methanotrophs to not only colonize the oxic-anoxic interface where methane concentrations are highest but also tolerate significant temporal fluctuations of this interface. Given that genomic surveys often show evidence of aerobic methanotrophs within anoxic zones, the ability to express MB (and thereby generate dioxygen) may be an important parameter in facilitating their ability to remove methane, a potent greenhouse gas, before it enters the atmosphere.

Study of the State of Surface Waters of the Northeast Caspian Sea During Development of Oil Fields

The relevance of the research is due to the fact that the Kashagan field has resumed oil and gas production, and up to this date more than 40 million tons of oil have been produced. In this regard, the study of the state of pollution of surface waters and its dynamics is relevant. This article is aimed at detecting the state of contamination with biogenic elements, oil products, phenol, synthetic surfactants and heavy metals. The leading approach to the study of this problem is State Standard 17.1.5.04-81; The seawater sampling procedure is carried out in accordance with ISO 5667-9: 1992 and ISO 5667-2. The article presents the results of research conducted in 2019 and the dynamics of pollution with pollutants in the area of the Kashagan, Kairan and Aktoty fields in the licensed territory. At the Kashagan field, samples were taken from 14 observation stations for the study. The fields of Kairan and Aktoty are currently preserved. In this regard, 2 observation stations were studied at each of these deposits and the results were compared with the results of the previous year. Based on the data obtained, it was revealed that biogenic elements remained at the same level and below the maximum permissible concentration for the entire study period. Comparison with last years’ studies shows that in 2019, the concentration of biogenic elements was lower than 2018. The content of oil products and synthetic surfactants for the study period was higher than in 2018, but lower than the MPC for the fisheries reservoir, and the phenol content was at the level of 2018 and exceeds the maximum permissible concentration by 3 times. Heavy metals for the entire study period were at the same level, with the exception of copper and iron, the concentration of which is higher than in 2018, but less than the MPC. The materials of the article are of practical value for scientists engaged in the study of the state of the inland seas, undergraduates, doctoral students.

Silver and gold nanoparticles as an integral part of nanooncology: current state of the problem

Gold and silver nanoparticles are easily synthesized and the most effective nanostructures in clinical practice. Their optical properties, ease of synthesis, colloidal stability and the ability to form any surface for easier conjugation with biological particles, the ability to individual multiple use, make them especially important in oncology. Gold and silver nanoparticles are capable of providing targeted drug delivery, which depends on the photothermal, photodynamic, and antiangiogenic properties of the metal. Due to their exceptional properties, these nanoparticles are considered as a potential tool for the diagnosis of various types of cancer and drug delivery. The non-toxic and non-immunogenic nature of gold and silver nanoparticles, as well as their high permeability and retention effect, provide additional advantages, allowing drugs to easily penetrate and accumulate at tumor sites. The effectiveness of precious metal nanoparticles as radiosensitizers, dose enhancers and contrast agents is gaining increasing recognition. An important problem associated with the use of biogenic metal nanoparticles is the study of their genotoxicity, since they play an important role in the initiation and progression of abnormalities, including genetic ones.

A Study and Optimization of Complexation of Cobalt Ions with Dihydroquercetin in Aqueous Solutions

This work continues a series of studies devoted to complex formation of ions of biogenic metals with the flavonoid dihydroquercetin (DHQ). The interaction of Со2+ ions with DHQ in aqueous solutions has been investigated. It has been found that, at different pH of a solution, complex compounds (CC) with different stoichiometry are formed; a variation of the pH value of a solution from 6.0 to 7.0 results in the formation of compounds (1)–(3) with the metal : flavonoid ligand ratio (Met : L) from 1 : 2 at рН 6.0 (1), through 2 : 3 at pH 6.4–6.7 (2), to 1 : 1 at рН 6.8–7.0 (3). By using the thermogravimetric method and the data of the elemental analysis, the most probable composition of the compounds with the determination of the amount of bound water has been proposed: [CoL2(H2O)4] for (1), [Co2L3(ОН)(H2O)4] for (2), and [CoL(ОН)(H2O)2] for (3). Conditions for the optimization of product yield in the complexation reaction of Со2+ ions with DHQ in an aqueous solution have been determined for compound (2): the рН value of solution 6.7; the reaction time 15 min; the temperature of the reaction solution 90°С; the molar ratio of the initial reagents DHQ : Со2+ 1 : 1.5; the initial concentration of DHQ 0.020 mol/L and that of Со2+ 0.030 mol/L; and the use of CoSO4 ⋅ 7H2O as a source of cobalt ions. The yield of the product is 81.8%.

Competition between abiogenic and biogenic metal cations in biological systems: Mechanisms of gallium‘s anticancer and antibacterial effect

Metal cations are key players in a plethora of essential biological processes. Over the course of evolution specific biological functions have been bestowed upon two dozen of (biogenic) metal species, some of the most frequently found being sodium, potassium, magnesium, calcium, zinc, manganese, iron, and copper. On the other hand, there is a group of less studied abiogenic metals like lithium, strontium and gallium that possess not known functions in living organisms, but, by mimicking the native ions and/or competing with them for binding to key metalloenzymes, may exert beneficial effect on humans in particular medical conditions. This review summarizes and critically examines the mechanisms of gallium's therapeutic action in anticancer and antibacterial therapies by exploiting the tools of molecular modeling and experimental biochemistry. These approaches allow for identifying key factors for Ga3+ beneficial effect such as the electrostatic interactions with the protein ligands, substrates or bacterial siderophores, intramolecular hydrogen bond formation, and pH and dielectric properties of the medium. Several intriguing questions concerning the gallium competition with the native ferric ion have found their answers.

Вплив наночастинок СеО2 на проростання насіння та синтез фенолів у проростках ялини європейської

Modern technologies make it possible to obtain nanoparticles of biogenic metals for use as an additional source of micronutrient for plants. However, the complexity of mass application of nanosized metal particles and their oxides is due to the significant differences in physicochemical properties of nanocrystalline structures which are dependent on production technology, nanoparticle size, surface charge (-potential), and stabilization methods. The biocompatibility and nature of nanoparticles has an impact on living organisms. Regarding the effectiveness and feasibility of using cerium dioxide nanoparticles in crop practice, there is no definitive conclusion. Due to difficulty in the preparation of planting material for seedlings of conifers, the study of the effect of nanocrystalline cerium dioxide on plants is not well researched. The aim of our research was to study the effect of nanocrystalline cerium dioxide solution on the germination of spruce seeds and then to evaluate its effect on the synthesis of phenols as components of the antioxidant system within seedlings. The research used methods for determining the germination energy and seed similarities. Other methods used in this research were determining the content of phenolic compounds, flavonoids, and phenolic antioxidants. The results showed that nanocrystalline cerium dioxide in a concentration of solution from 0.1 to 1.0 mg/mL stimulates the germination of spruce seeds. Under the influence of nanoparticles at a concentration of 0.1 mg/L in the tissues of spruce seedlings increases the content of phenolic compounds. The increase in antioxidant activity of phenols in seedling tissues while decreasing their total amount at a concentration of nanocrystalline cerium dioxide from 0.5 to 1.0 mg/L occurs when increasing the total pool of flavonoids, which are determined by high antioxidant activity. Nanocrystalline cerium dioxide is a promising material for stimulating germination energy and on the overall germination of spruce seeds.

Promotion of bioremediation performance in constructed wetland microcosms for acid mine drainage treatment by using organic substrates and supplementing domestic wastewater and plant litter broth

Gravel-based subsurface-flow constructed wetlands (CWs) amended with a walnut shell (WS) substrate were established to treat synthetic acid mine drainage (AMD) in this study, and artificial domestic wastewater (DW) and plant litter broth (PLB) were supplemented to enhance the performance. The CW media rapidly reached adsorption saturation with respect to metals (except Fe and Cr) without an external carbon source, while the addition of DW and PLB stimulated sulfate reduction activity and achieved efficient biogenic metal removal, primarily by the formation of hydroxide and sulfide precipitates and concomitant co-precipitation. The WS-amended CWs performed notably better than the control systems, not only in sequestering more metals and rapidly establishing favourable environments for biogenic metal abatement but also in supporting better growth of plants and functional microbes. The external organic carbon input greatly shaped the bacterial community compositions in the CWs, with substantial increases in the proportions of core functional populations involved in AMD biotreatment. Cooperation among Cellulomonas, Propioniciclava and sulfate-reducing bacteria (SRB), dominated by Desulfobulbus and Desulfatirhabdium, was the primary biogenic mechanism of AMD remediation in the CWs. Cellulosic waste-amended CWs with DW and PLB addition offer a promising eco-technology for AMD remediation.

Application of biogenic iron precipitation by strain H117 for tetracycline removal: mechanism of adsorption and activation.

To date, biogenic metals have opened up a window for new applications in adsorption of contaminants. But there is still little attention to be paid in the removal of tetracycline (TC) by biogenic iron precipitation (BIP). In this paper, the BIP, from iron-based mixotrophic denitrification batch reactor, was estimated for its adsorption property of TC under various parameters to simulate the behavior in aquatic environment. The maximum adsorption capacity for TC was 195.336mgg-1. Analyses of spectrum verified the existence of Fe3O4 and FeOOH in BIP, which was the main reason for the removal of TC. The adsorption kinetic and isotherm of TC were well fitted to Elovich and Langmuir isotherm models, respectively, indicating that the adsorption process was mainly controlled by chemical adsorption. Furthermore, we proposed a potential mechanism of adsorption: a combination of cation-π, hydrogen bonding (H-bonding), and electrostatic interaction. Additionally, the activation experiment showed that BIP could enhance the degradation of TC (more than 98.00% removal within 1.0h) by advanced oxidation process (AOP), due to the existence of FeOOH and Fe3O4. Considering its effectiveness in both adsorption and activation performance, BIP is highlighted as an economical and eco-friendly material for TC removal and offers a promising method to resolve sludge disposal in biological treatment of iron-rich groundwater.

Insights into palladium nanoparticles produced by Shewanella oneidensis MR-1: Roles of NADH dehydrogenases and hydrogenases

Biologically synthesized palladium nanoparticles (bio-Pd) have attracted considerable interest as promising green catalysts for environmental remediation. However, the mechanisms by which microorganisms produce bio-Pd remain unclear. In the present study, we investigated the roles of Shewanella oneidensis MR-1 and its NADH dehydrogenases and hydrogenases (HydA and HyaB) in bio-Pd production using formate as the electron donor. The roles of NADH dehydrogenases and hydrogenases were studied by inhibiting NADH dehydrogenases and using hydrogenase mutants (ΔhydA, ΔhyaB, and ΔhydAΔhyaB), respectively. The results showed ~97% reduction of palladium by S. oneidensis MR-1 after 24 h using 250 μM palladium and 500 μM formate. Electron microscopy images showed the presence of bio-Pd on both the outer and cytoplasmic membranes of S. oneidensis MR-1. However, the inhibition of NADH dehydrogenases in S. oneidensis MR-1 resulted in only ~61% reduction of palladium after 24 h, and bio-Pd were not found on the outer membrane. The mutants lacking one or two hydrogenases removed 91–96% of palladium ions after 24 h and showed more cytoplasmic bio-Pd but less periplasmic bio-Pd. To the best of our knowledge, this is the first study to demonstrate the role of NADH dehydrogenases of S. oneidensis MR-1 in the formation of bio-Pd on the outer membrane. It also demonstrates that the hydrogenases (especially HyaB) of S. oneidensis MR-1 contribute to the formation of bio-Pd in the periplasmic space. This study provides mechanistic insights into the production of biogenic metal nanoparticles towards their possible use in industrial and environmental applications.

Interaction of l-valinates of biogenic metals with 2-hydroxyethylamines

The interaction of copper(ii), zinc(ii), nickel(ii), and cobalt(ii) l-valinates with 2-hydroxyethylamines, viz., triethanolamine, diethanolamine, and tris(hydroxymethyl)aminomethane, was studied for the first time. Formation of new coordination compounds was confirmed using IR and electronic spectroscopies, mass spectrometry, and elemental analysis. The crystal structure of copper(ii) l-valinate was determined. The thermal stability and antimicrobial activity data for some prepared complexes of l-valine are also presented.

Biogenic Metal Oxides

Biogenic metal oxides (MxOy) feature structures as highly functional and unique as the organisms generating them. They have caught the attention of scientists for the development of novel materials by biomimicry. In order to understand how biogenic MxOy could inspire novel technologies, we have reviewed examples of all biogenic MxOy, as well as the current state of understanding of the interactions between the inorganic MxOy and the biological matter they originate from and are connected to. In this review, we first summarize the origins of the precursors that living nature converts into MxOy. From the point-of-view of our materials chemists, we present an overview of the biogenesis of silica, iron and manganese oxides, as the only reported biogenic MxOy to date. These MxOy are found across all five kingdoms (bacteria, protoctista, fungi, plants and animals). We discuss the key molecules involved in the biosynthesis of MxOy, the functionality of the MxOy structures, and the techniques by which the biogenic MxOy can be studied. We close by outlining the biomimetic approaches inspired by biogenic MxOy materials and their challenges, and we point at promising directions for future organic-inorganic materials and their synthesis.

THE INFLUENCE OF NANOPARTICLES OF BIOGENIC METALS ON CULTURING THE YEAST SACCHAROMYCES СEREVISIAE

The effect of nanoparticles of biogenic metals (Fe, Mg, Zn, Mn) and their combinations on culturing the yeast Saccharomyces cerevisiae and on fermentation of sugar-containing raw materials into ethanol have been investigated . The research involved the use of nanometal preparations obtained by volumetric electric-spark dispersion. It has proved effective to add nanozinc and a preparation containing nanomanganese and nanomagnesium, prior to yeast cultivation, to the growth media agar and wort agar in the concentrations 0.5 μg/cm3 and 11 μg/cm3 respectively. The experimental yeast grown on the medium containing these preparations increased the alcohol concentration in the distiller’s wort by 0.2%, whereas the content of unfermented carbohydrates remained within the prescribed limits 0.32–0.39 g/100 сm3. The yeast biomass increased by 1.2–1.4 times. Zinc and manganese/magnesium nanopreparations increased the maltase and invertase activities of the yeast under study by 40–25%. The nanoiron preparation contributed to inhibiting the fermentation activity of the yeast biomass. Biogenic metal nanocomplexes are used by yeast as an additional nutrient source. They form organometallic and intracomplex active compounds with yeast cell enzymes, primarily with hexokinase, aldolase, enolase. This intensifies synthesis of enzymes and increases their catalytic effect. The results obtained prove the effectiveness of biogenic metal nanopreparations as catalysts for biochemical transformations in a yeast cell. Using nanometals increases the productivity of bakery yeast, improves the technological process of alcoholic fermentation, and offers ample opportunity to increase the activity of enzyme preparations in the course of their production.