Bacterial Synthesis of Metal Oxide Nanomaterials

At least one-third of the elements in the Periodic Table have experienced changes in valence states induced by microbial achvity. While some metals (iron, calcium, potassium) serve as an essential source for nutrients in bacterial systems, others are introduced as contaminants (lead, nickel, cobalt, cadmium) [2]. This cohabitation with such heavy-metal pollutants has forced organisms among marine bacteria to develop a high metal tolerance, which in turn makes them an interesting source for templahng the constrained synthesis of metal/metal oxide nanoparticles. 

On the other hand, biologically produced microbes reduce metal ions in aqueous media to form stable suspensions of nanoparticles coated with biomolecules (proteins, peptides). This coating not only activates the modified properties of the nanoparticle, but also prevents particle agglomeration, thus stimulating the growth of discrete nanoparticles within a solution. 

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