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Application of Nanomaterials in Environmental Pollution Abatement and Their Impact on Ecological Sustainability: Recent Status and Future Perspective
Published in Jyoti Ranjan Rout, Rout George Kerry, Abinash Dutta, Biotechnological Advances for Microbiology, Molecular Biology, and Nanotechnology, 2022
Syed Nikhat Ahmed, Subhashree Subhadarsini Mishra, Jayanta Kumar Sahu, Sabita Shroff, Prajna Paramita Naik, Iswar Baitharu, Sanjat Kumar Sahu
An alternative method of nanomaterials synthesis that does not involve the use of toxic chemicals is the biogenic method (Figure 23.1). The biogenic method involves natural substances derived from plants, bacteria, algae, fungi, yeast, actinomycetes that produce reducing, capping, and stabilizing agents required for the synthesis of the nanomaterials. The biogenic method is an ecologically sustainable as well as an economically viable option. Manufacturing metallic nanomaterials using naturally occurring vitamins, polyphenols, carbohydrates, amino acids, and natural surfactants are gradually gaining wider acceptability (Dhillon et al., 2012). The biological method of nanomaterial synthesis is rapid, eco-friendly, and suitable for large scale production compared to available conventional synthesis methods. Numbers of different species of bacteria have been reported to catalyze biogenic production of various inorganic nanomaterials that are otherwise very difficult to synthesize using chemical methods. Certain magnetotactic bacteria have the ability to produce magnetic nanoparticles, or magnetosomes. Nanomaterials such as nano- and microZnO rods are synthesized by Magnetospirillum magnetotacticum, Incubation of E. coli bacterial species with cadmium chloride and sodium sulfide can lead to the generation of cadmium sulfide nanomaterials. Pseudomonas stutzeri is known to synthesize silver-based nanocrystals. Sulfate-reducing bacteria are used to produce sphalerite (ZnS) nanoparticles (Table 23.2).
What Have We Learnt From the Nature and History?
Published in Rajendra Kumar Goyal, Nanomaterials and Nanocomposites, 2017
Magnetotactic bacteria (MTB) are a diverse group of microorganisms with the ability to orient and migrate along geomagnetic field lines. This ability is based on specific intracellular nanostructures having membrane-bound crystals of the magnetic iron minerals magnetite (Fe3O4) or greigite (Fe3S4). These nanocrystals function as tiny compasses that allow the microbes to navigate using Earth's geomagnetic field and also help the bacteria in locating the growth favorable conditions within the water column or aquatic sediment. They can push themselves through the water by rotating their helical flagella and interestingly, they can swim at speeds nearly twice that of Escherichia coli cells [18]. Figure 4.9 shows a TEM bright-field image of a single cell of Magnetospirillum magnetotacticum [19].
Static, Low-Frequency, and Pulsed Magnetic Fields in Biological Systems
Published in James C. Lin, Electromagnetic Fields in Biological Systems, 2016
Magnetotactic bacteria are microorganisms that orient and migrate along magnetic field lines. Magnetotactic bacteria contain membrane-bound intracellular iron crystals called magnetosomes (Komeili et al. 2006). Magnetosomes comprise a magnetic nano-crystal surrounded by a lipid bilayer membrane. These unique prokaryotic organelles align inside magnetotactic bacterial cells and serve as an intracellular compass allowing the bacteria to navigate along the geomagnetic field in aquatic environments. Polar magnetotactic bacteria in vertical chemical gradients are thought to respond to high oxygen levels by swimming downward into areas with low or no oxygen (toward geomagnetic north in the Northern Hemisphere and geomagnetic south in the Southern Hemisphere). Simmons, Bazylinski, and Edwards (2006) identified populations of polar magnetotactic bacteria in the Northern Hemisphere that respond to high oxygen levels by swimming toward geomagnetic south, which is the opposite of all previously reported magnetotactic behavior. The percentage of magnetotactic bacteria with south polarity in the environment is positively correlated with high redox potential. The coexistence of magnetotactic bacteria with opposing polarities in the same redox environment conflicts with current models of the adaptive value of magnetotaxis.
Comparative ecotoxicity assessment of magnetosomes and magnetite nanoparticles
Published in International Journal of Environmental Health Research, 2020
Varalakshmi Raguraman, K. Suthindhiran
Nevertheless, magnetosomes are biomineralized and synthesized by a group of magnetotactic bacteria (MTB) under controlled growth conditions. Magnetosomes are usually composed of magnetite (Fe3O4) and are enclosed by lipid bilayer membrane consists of phospholipids such as phosphatidylethanolamine, phosphatidyl glycerol, some amino groups and specific proteins (Balkwill et al. 1980; Gorby et al. 1988; Bazylinski & Frankel., 2004; Komeili et al. 2006). The membrane not only controls the crystal size and shape, but also prevents the magnetosome from aggregation (Timko et al. 2009). Magnetosomes are gaining great attention because of their high biocompatibility, less/no toxicity and large surface to volume ratio aided by naturally forming lipid bilayer membrane (Faivre et al. 2008). Though few reports are available on the toxicity of MNPs and magnetosomes, a comparative toxicity assessment on various ecological models under identical conditions is lacking. The present study dealt with the comparative toxicity evaluation of MNPs and magnetosomes using both in vivo and in vitro assays. We compared the size and morphology, crystallinity, cell viability and toxicity evaluation on various models such as red blood cell (RBC), macrophage cell lines, onion root tip, Artemia salina and in zebrafish embryos.
Magnetic sorbents biomineralization on the basis of iron sulphides
Published in Environmental Technology, 2018
Jana Jencarova, Alena Luptakova, Nikola Vitkovska, Dalibor Matysek, Petr Jandacka
Among the numerous organisms capable of biomineralization, an important group of microbes that form intracellular crystal of magnetic iron oxide or iron sulphide minerals represent magnetotactic bacteria. Most magnetotactic bacteria belong to the α-Proteobacteria, but some have also been affiliated to δ-Proteobacteria [3]. There is a specific group of them, multicellular magnetotactic prokaryotes that are distinguished from unicellular bacteria by their multicellularity, swimming behaviour, life cycle and phylogenetic affiliation and belong to δ-Proteobacteria. They are closely related to the sulphate-reducing bacteria (SRB), and all of the cells within them are of the same phylotype [4]. Many studies have been oriented on greigite, pyrite or magnetite biomineralization in magnetotactic prokaryotes [5,6]. For example, Sakaguchi et al. [7] and Byrne et al. [8] studied magnetite biomineralization in Desulfovibrio magneticus sp. RS-1 (affiliated with the genus Desulfovibrio of the δ-Proteobacteria). It was found out that this bacterium forms irregular or bullet-shaped crystals. Spherical multicellular magnetotactic prokaryotes can biomineralize magnetite and/or greigite crystals, or may even lack magnetosomes.