Stable iodine isotopes are essential for humans as they are necessary for producing thyroid gland hormones. However, there are hazardous radioactive iodine isotopes that are emitted into the environment through radioactive waste generated by nuclear power plants, nuclear weapon tests, and medical practice. Due to the biophilic character of iodine radionuclides and their enormous biomagnification potential, their elimination from contaminated environments is essential to prevent the spread of radioactive pollution in ecosystems. Since microorganisms play a vital role in controlling iodine cycling and fate in the environment, they also can be efficiently utilized in solving the issue of contamination spread. Thus, this paper summarizes all known on microbial processes that are involved in iodine transformation to highlight their prospects in remediation of the sites contaminated with radioactive iodine isotopes.
- Klíčová slova
- biomethylation, biooxidation, bioreduction, bioremediation, iodine,
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Manganese oxides are considered an essential component of natural geochemical barriers due to their redox and sorptive reactivity towards essential and potentially toxic trace elements. Despite the perception that they are in a relatively stable phase, microorganisms can actively alter the prevailing conditions in their microenvironment and initiate the dissolution of minerals, a process that is governed by various direct (enzymatic) or indirect mechanisms. Microorganisms are also capable of precipitating the bioavailable manganese ions via redox transformations into biogenic minerals, including manganese oxides (e.g., low-crystalline birnessite) or oxalates. Microbially mediated transformation influences the (bio)geochemistry of manganese and also the environmental chemistry of elements intimately associated with its oxides. Therefore, the biodeterioration of manganese-bearing phases and the subsequent biologically induced precipitation of new biogenic minerals may inevitably and severely impact the environment. This review highlights and discusses the role of microbially induced or catalyzed processes that affect the transformation of manganese oxides in the environment as relevant to the function of geochemical barriers.
- Klíčová slova
- biotransformation, manganese, manganese oxides, microorganisms, sorption,
- MeSH
- mangan * chemie MeSH
- minerály chemie MeSH
- oxidace-redukce MeSH
- oxidy * chemie MeSH
- sloučeniny manganu chemie MeSH
- životní prostředí MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- mangan * MeSH
- manganese oxide MeSH Prohlížeč
- minerály MeSH
- oxidy * MeSH
- sloučeniny manganu MeSH
Fungi contain species with a plethora of ways of adapting to life in nature. Consequently, they produce large amounts of diverse biomolecules that can be generated on a large scale and in an affordable manner. This makes fungi an attractive alternative for many biotechnological processes. Ascomycetes and basidiomycetes are the most commonly used fungi for synthesis of metal-containing nanoparticles (NPs). The advantages of NPs created by fungi include the use of non-toxic fungus-produced biochemicals, energy efficiency, ambient temperature, pressure conditions, and the ability to control and tune the crystallinity, shape, and size of the NPs. Furthermore, the presence of biomolecules might serve a dual function as agents in NP formation and also capping that can tailor the (bio)activity of subsequent NPs. This review summarizes and reviews the synthesis of different metal, metal oxide, metal sulfide, and other metal-based NPs mediated by reactive media derived from various species. The phyla ascomycetes and basidiomycetes are presented separately. Moreover, the practical application of NP mycosynthesis, particularly in the fields of biomedicine, catalysis, biosensing, mosquito control, and precision agriculture as nanofertilizers and nanopesticides, has been studied so far. Finally, an outlook is provided, and future recommendations are proposed with an emphasis on the areas where mycosynthesized NPs have greater potential than NPs synthesized using physicochemical approaches. A deeper investigation of the mechanisms of NP formation in fungi-based media is needed, as is a focus on the transfer of NP mycosynthesis from the laboratory to large-scale production and application.
- Klíčová slova
- antimicrobial agent, biomedicine, catalyst, extracellular extracts, fungal synthesis, intracellular extracts, nanobiosensors, nanofertilizer, precision agriculture,
- MeSH
- Ascomycota * MeSH
- Basidiomycota * MeSH
- kovové nanočástice * chemie MeSH
- kovy MeSH
- oxidy MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- kovy MeSH
- oxidy MeSH
In the 21st century, nanomaterials play an increasingly important role in our lives with applications in many sectors, including agriculture, biomedicine, and biosensors. Over the last two decades, extensive research has been conducted to find ways to synthesise nanoparticles (NPs) via mediation with fungi or fungal extracts. Mycosynthesis can potentially be an energy-efficient, highly adjustable, environmentally benign alternative to conventional physico-chemical procedures. This review investigates the role of metal toxicity in fungi on cell growth and biochemical levels, and how their strategies of resistance, i.e., metal chelation, biomineral formation, biosorption, bioaccumulation, compartmentalisation, and efflux of metals from cells, contribute to the synthesis of metal-containing NPs used in different applications, e.g., biomedical, antimicrobial, catalytic, biosensing, and precision agriculture. The role of different synthesis conditions, including that of fungal biomolecules serving as nucleation centres or templates for NP synthesis, reducing agents, or capping agents in the synthesis process, is also discussed. The authors believe that future studies need to focus on the mechanism of NP synthesis, as well as on the influence of such conditions as pH, temperature, biomass, the concentration of the precursors, and volume of the fungal extracts on the efficiency of the mycosynthesis of NPs.
- Klíčová slova
- biomolecule, biosynthesis, fungus, green synthesis, metal oxide nanoparticle, metallic nanoparticle, nanomaterial,
- MeSH
- bioakumulace MeSH
- biologický transport MeSH
- katalýza MeSH
- kovové nanočástice * MeSH
- redukční činidla MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- Názvy látek
- redukční činidla MeSH
Pseudomonas biofilms have been studied intensively for several decades and research outcomes have been successfully implemented in various medical and agricultural applications. Research on biofilm synthesis and composition has also overlapped with the objectives of environmental sciences, since biofilm components show exceptional physicochemical properties applicable to remediation techniques. Especially, exopolysaccharides (ExPs) have been at the center of scientific interest, indicating their potential in solving the environmental issues of heavy metal land and water contamination via sorptive interactions and flocculation. Since exposure to heavy metal via contaminated water or soil poses an imminent risk to the environment and human health, ExPs provide an interesting and viable solution to this issue, alongside other effective and green remedial techniques (e.g., phytostabilization, implementation of biosolids, and biosorption using agricultural wastes) aiming to restore contaminated sites to their natural, pollution-free state, or to ameliorate the negative impact of heavy metals on the environment. Thus, we discuss the plausible role and performance of Pseudomonas ExPs in remediation techniques, aiming to provide the relevant available and comprehensive information on ExPs' biosynthesis and their usage in heavy metal remediation or other environmental applications, such as wastewater treatment via bioflocculation and soil remediation.
- Klíčová slova
- Pseudomonas, bioremediation, biosorption, exopolysaccharides, heavy metals,
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Bioleaching of mineral phases plays a crucial role in the mobility and availability of various elements, including selenium. Therefore, the leachability of selenium associated with the surfaces of ferric and manganese oxides and oxyhydroxides, the prevailing components of natural geochemical barriers, has been studied in the presence of filamentous fungus. Both geoactive phases were exposed to selenate and subsequently to growing fungus Aspergillus niger for three weeks. This common soil fungus has shown exceptional ability to alter the distribution and mobility of selenium in the presence of both solid phases. The fungus initiated the extensive bioextraction of selenium from the surfaces of amorphous ferric oxyhydroxides, while the hausmannite (Mn3O4) was highly susceptible to biodeterioration in the presence of selenium. This resulted in specific outcomes regarding the selenium, iron, and manganese uptake by fungus and residual selenium concentrations in mineral phases as well. The adverse effects of bioleaching on fungal growth are also discussed.
- Klíčová slova
- bioleaching, fungi, iron, manganese, selenate,
- Publikační typ
- časopisecké články MeSH
Iron-based nanomaterials have high technological impacts on various pro-environmental applications, including wastewater treatment using the co-precipitation method. The purpose of this research was to identify the changes of iron nanomaterial's structure caused by the presence of selenium, a typical water contaminant, which might affect the removal when the iron co-precipitation method is used. Therefore, we have investigated the maturation of co-precipitated nanosized ferric oxyhydroxides under alkaline conditions and their thermal transformation into hematite in the presence of selenite and selenate with high concentrations. Since the association of selenium with precipitates surfaces has been proven to be weak, the mineralogy of the system was affected insignificantly, and the goethite was identified as an only ferric phase in all treatments. However, the morphology and the crystallinity of ferric oxyhydroxides was slightly altered. Selenium affected the structural order of precipitates, especially at the initial phase of co-precipitation. Still, the crystal integrity and homogeneity increased with time almost constantly, regardless of the treatment. The thermal transformation into well crystalized hematite was more pronounced in the presence of selenite, while selenate-treated and selenium-free samples indicated the presence of highly disordered fraction. This highlights that the aftermath of selenium release does not result in destabilization of ferric phases; however, since weak interactions of selenium are dominant at alkaline conditions with goethite's surfaces, it still poses a high risk for the environment. The findings of this study should be applicable in waters affected by mining and metallurgical operations.
- Klíčová slova
- Mössbauer spectroscopy, ferric oxyhydroxides, selenium, sorption,
- MeSH
- alkálie chemie MeSH
- chemická precipitace MeSH
- krystalizace MeSH
- kyselina seleničitá chemie MeSH
- kyselina selenová chemie MeSH
- minerály chemie MeSH
- sloučeniny železa chemie MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- spektroskopie Mossbauerova MeSH
- teplota MeSH
- železité sloučeniny chemie MeSH
- železo chemie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- alkálie MeSH
- ferric oxyhydroxide MeSH Prohlížeč
- goethite MeSH Prohlížeč
- kyselina seleničitá MeSH
- kyselina selenová MeSH
- minerály MeSH
- sloučeniny železa MeSH
- železité sloučeniny MeSH
- železo MeSH
We present a biological profile of 16 Aspergillus niger environmental isolates from different types of soils and solid substrates across a pH range, from an ultra-acidic (<3.5) to a very strongly alkaline (>9.0) environment. The soils and solid substrates also differ in varying degrees of anthropic pollution, which in most cases is caused by several centuries of mining activity at old mining sites, sludge beds, ore deposits, stream sediments, and coal dust. The values of toxic elements (As, Sb, Zn, Cu, Pb) very often exceed the limit values. The isolates possess different macro- and micromorphological features. All the identifications of Aspergillus niger isolates were confirmed by molecular PCR analysis and their similarity was expressed by RAMP analysis. The biochemical profile of isolates based on FF-MicroPlate tests from the Biolog system showed identical biochemical reactions in 50 tests, while in 46 tests the utilisation reactions differed. The highest similarity of strains isolated from substrates with the same pH, as well as the most suitable biochemical tests for analysis of the phenotypic similarity of isolated strains, were confirmed when evaluating the biochemical profile using multicriterial analysis in the Canoco program. The isolates were screened for mycotoxin production by thin-layer chromatography (TLC), as well. Two of them were able to synthesise ochratoxin A, while none produced fumonisins under experimental conditions. Presence of toxic compounds in contaminated sites may affect environmental microscopic fungi and cause the genome alteration, which may result in changes of their physiology, including the production of different (secondary) metabolites, such as mycotoxins.
- Klíčová slova
- Aspergillus niger environmental isolates, Biolog FF MicroplateTM, extrolite profile, molecular analyses, multi-criteria data analysis,
- Publikační typ
- časopisecké články MeSH
In this work, the viability of bioaccumulation and bioextraction processes for arsenic removal from contaminated waters, as well as the recycling of arsenate-treated amorphous ferric oxyhydroxide adsorbent (FeOOH) were evaluated using the common soil microscopic filamentous fungus Aspergillus niger. After treating the contaminated arsenate solution (100 mg As L-1) with FeOOH, the remaining solution was exposed to the growing fungus during a static 19-day cultivation period to further decrease the arsenic concentration. Our data indicated that although the FeOOH adsorbent is suitable for arsenate removal with up to 84% removal efficiency, the fungus was capable of accumulating only up to 13.2% of the remaining arsenic from the culture media. This shows that the fungus A. niger, although highly praised for its application in environmental biotechnology research, was insufficient for decreasing the arsenic contamination to an environmentally acceptable level. However, the bioextraction of arsenic from arsenate-treated FeOOH proved relatively effective for reuse of the adsorbent. Due to its production of acidic metabolites, which decreased pH below 2.7, the fungal strain was capable of removing of up to 98.2% of arsenic from the arsenate-treated FeOOH adsorbent.
- Klíčová slova
- arsenic, bioaccumulation, bioextraction, ferric oxyhydroxides, filamentous fungi,
- Publikační typ
- časopisecké články MeSH
Ferric oxyhydroxides are natural scavengers of antimony, thus, they contribute significantly to antimony immobilization in soils and sediments. Recent studies, however, usually omit microbial influence on geochemically stable antimony-ferric oxyhydroxide association. Therefore, we have evaluated fungal contribution to antimony mobility during static cultivation of common soil fungus Aspergillus niger in presence of ferric oxyhydroxides. Our results indicate distinguished effect of fungus on antimony distribution at two different antimony concentrations that were used for antimony pre-adsorbtion onto ferric oxyhydroxides prior to the inoculation. Approximately 36% of antimony was bioextracted by fungus from antimony bearing ferric oxyhydroxide after 14-day cultivation when the 8.9 mg·L-1 antimony concentration was used for pre-adsorption. However, no statistically significant change of antimony content in ferric oxyhydroxides was observed after cultivation when initial 48 mg·L-1 antimony concentration was used for pre-adsorption. As Mössbauer spectroscopy and XRD analysis indicated, nanosized akageneite, goethite, and lepidocrocite enhanced their crystallinity during cultivation, while hematite was identified only after the cultivation. Nevertheless, presence of ferric oxyhydroxides at both initial concentrations enabled transformation of antimony into volatile derivatives, and almost 9.5% of antimony was biovolatilized after cultivation. These results contribute significantly to environmental geochemistry of antimony-ferric oxyhydroxides association and highlight the importance of microbial activity in relation to ferric component of natural geochemical barriers.
- Klíčová slova
- Antimony, Aspergillus niger, Bioleaching, Biovolatilization,
- MeSH
- adsorpce MeSH
- antimon chemie metabolismus MeSH
- biotransformace MeSH
- houby fyziologie MeSH
- látky znečišťující půdu chemie metabolismus MeSH
- železité sloučeniny chemie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- antimon MeSH
- ferric oxide MeSH Prohlížeč
- ferric oxyhydroxide MeSH Prohlížeč
- látky znečišťující půdu MeSH
- železité sloučeniny MeSH
