Microbially Mediated Oxidative Precipitation Reactions

The oxidation of iron(II) and manganese(II) usually leads to the formation of insoluble metal oxides, hydroxides, and oxyhydroxides which are of wide-ranging environmental importance. Microorganisms catalyze the oxidation of Fe(II) and Mn(II), however, the mechanisms of metal oxidation, particularly in the case of Mn(II) oxidation, and the effect microorganisms have on the properties of the solid phases, are not well known. The state of knowledge concerning Fe and Mn biomineralization is briefly reviewed. Considerable progress has been made in recent years in understanding the mechanisms and products of Mn(II) oxidation by bacteria. Results obtained using classical and modern approaches, including biochemical, molecular biological, mineralogical and stable oxygen isotopes have provided new insights into bacterial Mn(II) oxidation.