The Microbiology of Manganese Nodules.
Final technical rept. 1 Dec 64-30 Nov 70,
RENSSELAER POLYTECHNIC INST TROY N Y DEPT OF BIOLOGY
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The bacterial activity related to manganese accretion to nodules and manganic oxide reduction of nodules was studied. Manganese accretion to nodules involves two steps, 1 MnII capture by preexistent nodule and 2 oxidation of the captured MnII to manganic oxide. The second step can be biologically catalyzed by an enzyme system in appropriate bacteria that appears to be membrane-bound and probably includes cytochrome and cytochrome oxidase. Oxidation of free Mn2 was not observed. The enzymatic process is possible at hydrostatic pressures corresponding to depths at which nodules are found in the ocean. Manganic oxide reduction in nodules is possible in the presence of glucose. The reduction reaction is catalyzed by a membrane-bound MnO2 reductase in appropriate bacteria. One component of the reductase is inducible by Mn2 in the presence of O2. Oxygen does not suppress enzymatic manganic oxide reduction. The manganic oxide reductase is a different enzyme system from ferric oxide reductase. Enzymatic manganic oxide reduction is possible at hydrostatic pressures corresponding to depths at which nodules are found in the ocean. The iron component of nodules is not appreciably solubilized by the bacteria during manganese solubilization. Author
- Biological Oceanography