Oxidation and Reduction of Iron by Bacteria

Organic Carbon Oxidation Microbially Coupled to Reduction of Fe(III)(hydr)oxide. More and more evidence is accumulating that bacteria can grow anaerobically by coupling organic carbon oxidation to the dissimilatory reduction of iron(III) oxides (Nealson, 1982 Arnold et al., 1986 Lovely and Philips, 1988 Nealson and Myers, 1990). 

The Fe(II)-cytochrome c oxidoreductase catalyzes the reduction of cytochrome c-552 with ferrous ion but does not catalyze the direct reduction of rusticyanin. This agrees with the finding of Hazra et al. (1992) that rusticyanin is reduced via cytochrome c. Blake and Shuts (1994) have claimed that the oxidation of ferrous ion occurs by the catalysis of Fe(II)-rusticyanin oxidoreductase. However, as their enzyme preparation probably contained cytochrome c as a contaminant, its catalysis could be the reduction of rusticyanin by Fe(II)-cytochrome c oxidoreductase mediated by cytochrome c. It has been reported that rusticyanin is not present in Leptospirillum ferrooxidans (Blake et al., 1993). This may mean that rusticyanin is not necessarily required for the oxidation of ferrous ion by the iron-oxidizing bacteria. 

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