ABSTRACT
Dissimilatory iron-reducing bacteria reduce the iron and crystallize iron nanoparticles. The iron-reducing bacteria use insoluble Fe(III) hydroxides in the environment as a terminal electron acceptor, enter the cell wall, and reduce the Fe(III) to Fe(II) synthesizing sulfides, silicates, and carbonates of iron. Reduced Fe(II) sorbed on the bacterial cell wall reacts with the excessive Fe(III) oxides present in nature to form magnetite and hematite. There is very scanty information on the ability of the dissimilatory iron-reducing bacteria and their manner of producing extracellular crystals. Thischapterdescribes the various species involved in such biomineralization processes and the mechanism involved in vogue. The diversity of various types of iron minerals formed vis-à-vis mechanism is also described in detail.
