[Functional significance of bivalent iron and manganese oxidation in Leptothrix pseudoochraceae]

The effect of oxidation of bivalent compounds of iron and manganese was studied on the growth of filamentous iron bacteria. The stimulating action of these metals could not be attributed to utilization of the energy of their oxidation in the assimilation of carbon dioxide or in lithoheterotrophic processes. The cells yield increased because the metal ions removed the toxic metabolite, hydrogen peroxide, which was formed in the respiratory chain upon oxidation of an organic substrate. This function of bivalent metals in detoxication of hydrogen peroxide accounts for the ecological confinement of iron bacteria to certain environment.