Bacteria and heavy metals: Metal cofactors involved in electron transfer and catalytic reduction during anaerobic bacterial respiration

From the early stages of life on earth to the present day, many bacteria have evolved respiratory pathways to generate energy from a range of molecules; these include organic and inorganic, soluble and insoluble compounds that are either present as naturally occurring molecules in the environment or are released through industrial, municipal or agricultural waste. This results in bacteria affecting the availability of a number of biologically important elements, including carbon, nitrogen and sulfur, as well as iron and manganese.