Simultaneous bioremediation of phenol and tellurite by Lysinibacillus sp. EBL303 and characterization of biosynthesized Te nanoparticles

Tellurium and Nano-Tellurium: Medicine or Poison?

Tellurium (Te) is the heaviest stable chalcogen and is a rare element in Earth's crust (one to five ppb). It was discovered in gold ore from mines in Kleinschlatten near the present-day city of Zlatna, Romania. Industrial and other applications of Te focus on its inorganic forms. Tellurium can be toxic to animals and humans at low doses. Chronic tellurium poisoning endangers the kidney, liver, and nervous system. However, Te can be effective against bacteria and is able to destroy cancer cells. Tellurium can also be used to develop redox modulators and enzyme inhibitors. Soluble salts that contain Te had a role as therapeutic and antimicrobial agents before the advent of antibiotics. The pharmaceutical use of Te is not widespread due to the narrow margin between beneficial and toxic doses, but there are differences between the measure of toxicity based on the Te form. Nano-tellurium (Te-NPs) has several applications: it can act as an adsorptive agent to remove pollutants, and it can be used in antibacterial coating, photo-catalysis for the degradation of dyes, and conductive electronic materials. Nano-sized Te particles are the most promising and can be produced in both chemical and biological ways. Safety assessments are essential to determine the potential risks and benefits of using Te compounds in various applications. Future challenges and directions in developing nano-materials, nano-alloys, and nano-structures based on Te are still open to debate.

Applications of Fourier Transform-Infrared spectroscopy in microbial cell biology and environmental microbiology: advances, challenges, and future perspectives

Microorganisms play pivotal roles in shaping ecosystems and biogeochemical cycles. Their intricate interactions involve complex biochemical processes. Fourier Transform-Infrared (FT-IR) spectroscopy is a powerful tool for monitoring these interactions, revealing microorganism composition and responses to the environment. This review explores the diversity of applications of FT-IR spectroscopy within the field of microbiology, highlighting its specific utility in microbial cell biology and environmental microbiology. It emphasizes key applications such as microbial identification, process monitoring, cell wall analysis, biofilm examination, stress response assessment, and environmental interaction investigation, showcasing the crucial role of FT-IR in advancing our understanding of microbial systems. Furthermore, we address challenges including sample complexity, data interpretation nuances, and the need for integration with complementary techniques. Future prospects for FT-IR in environmental microbiology include a wide range of transformative applications and advancements. These include the development of comprehensive and standardized FT-IR libraries for precise microbial identification, the integration of advanced analytical techniques, the adoption of high-throughput and single-cell analysis, real-time environmental monitoring using portable FT-IR systems and the incorporation of FT-IR data into ecological modeling for predictive insights into microbial responses to environmental changes. These innovative avenues promise to significantly advance our understanding of microorganisms and their complex interactions within various ecosystems.

Simultaneous bioreduction of tellurite and selenite by Yarrowia lipolytica, Trichosporon cutaneum, and their co-culture along with characterization of biosynthesized Te-Se nanoparticles

BACKGROUND

Natural and anthropogenic activities, such as weathering of rocks and industrial processes, result in the release of toxic oxyanions such as selenium (Se) and tellurium (Te) into the environment. Due to the high toxicity of these compounds, their removal from the environment is vital.

RESULTS

In this study, two yeast strains, Yarrowia lipolytica and Trichosporon cutaneum, were selected as the superior strains for the bioremediation of tellurium and selenium. The reduction analyses showed that exposure to selenite induced more detrimental effects on the strains compared to tellurite. In addition, co-reduction of pollutants displayed almost the same results in selenite reduction and more than ~ 20% higher tellurite reduction in 50 h, which shows that selenite triggered higher tellurite reduction in both strains. The selenite and tellurite kinetics of removal were consistent with the first-order model because of their inhibitory behavior. The result of several characterization experiments, such as FE-SEM (Field emission scanning electron microscopy), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and dispersive X-ray (EDX) on Te-Se nanoparticles (NPs) revealed that the separated Te-Se NPs were needle-like, spherical, and amorphous, consisted of Te-Se NPs ranging from 25 to 171 nm in size, and their surface was covered with different biomolecules.

CONCLUSIONS

Remarkably, this work shows, for the first time, the simultaneous bioreduction of tellurite and selenite and the production of Te-Se NPs using yeast strains, indicating their potential in this area, which may be applied to the nanotechnology industry and environmental remediation.

Microbial mechanisms to transform the super-trace element tellurium: a systematic review and discussion of nanoparticulate phases

Tellurium is a super-trace metalloid on Earth. Owing to its excellent physical and chemical properties, it is used in industries such as metallurgy and manufacturing, particularly of semiconductors and - more recently - solar panels. As the global demand for tellurium rises, environmental issues surrounding tellurium have recently aroused concern due to its high toxicity. The amount of tellurium released to the environment is increasing, and microorganisms play an important role in the biogeochemical cycling of environmental tellurium. This review focuses on novel developments on tellurium transformations driven by microbes and includes the following sections: (1) history and applications of tellurium; (2) toxicity of tellurium; (3) microbial detoxification mechanisms against soluble tellurium anions including uptake, efflux and methods of reduction, and reduced ability to cope with oxidation stress or repair damaged DNA; and (4) the characteristics and applications of tellurium nanoparticles (TeNPs) produced by microbes. This review raises the awareness of microorganisms in tellurium biogeochemical cycling and the growing applications for microbial tellurium nanoparticles.

Selenite bioreduction by a consortium of halophilic/halotolerant bacteria and/or yeasts in saline media

Selenium oxyanions are released into environments by natural and anthropogenic activities and are present in agricultural and glass manufacturing wastewater in several locations worldwide. Excessive amounts of this metalloid have adverse effects on the health of living organisms. Halophilic and halotolerant microorganisms were selected for selenium oxyanions remediation due to presence of significant amount of salt in selenium-containing wastewater. Effects of aeration, carbon sources, competitive electron acceptors, and reductase inhibitors were investigated on SeO₃^2- bio-removal. Additionally, NO₃^--containing wastewater were exploited to investigate SeO₃^2- remediation in synthetic agricultural effluents. The results showed that the SeO₃^2- removal extent is maximum in aerobic conditions with succinate as a carbon source. SO₄^2- and PO₄^3- do not significantly interfere with SeO₃^2- reduction, while WO₄^2- and TeO₃^2- decrease the SeO₃^2- removal percentage (up to 35 and 37%, respectively). Furthermore, NO₃^- had an adverse effect on SeO₃^2- biotransformation by our consortia. All consortia reduced SeO₃^2- in synthetic agricultural wastewaters with a 45-53% removal within 120 h. This study suggests that consortia of halophilic/halotolerant bacteria and yeasts could be applied to treat SeO₃^2--contaminated drainage water. In addition, sulphates, and phosphates do not interfere with selenite bioreduction by these consortia, which makes them suitable candidates for the bioremediation of selenium-containing wastewater.

Use of Microbial Consortia in Bioremediation of Metalloid Polluted Environments

Metalloids are released into the environment due to the erosion of the rocks or anthropogenic activities, causing problems for human health in different world regions. Meanwhile, microorganisms with different mechanisms to tolerate and detoxify metalloid contaminants have an essential role in reducing risks. In this review, we first define metalloids and bioremediation methods and examine the ecology and biodiversity of microorganisms in areas contaminated with these metalloids. Then we studied the genes and proteins involved in the tolerance, transport, uptake, and reduction of these metalloids. Most of these studies focused on a single metalloid and co-contamination of multiple pollutants were poorly discussed in the literature. Furthermore, microbial communication within consortia was rarely explored. Finally, we summarized the microbial relationships between microorganisms in consortia and biofilms to remove one or more contaminants. Therefore, this review article contains valuable information about microbial consortia and their mechanisms in the bioremediation of metalloids.