Managanese oxidation by Sphaerotilus discophorus.

Johnson, A. H. (Washington State University, Pullman), and J. L. Stokes. Manganese oxidation by Sphaerotilus discophorus. J. Bacteriol. 91:1543-1547. 1966.-Cell suspensions of Sphaerotilus discophorus in 0.02 m potassium phosphate buffer (pH 7.2) readily oxidized MnSO(4) to dark-brown manganic oxide. The latter appeared to be MnO(2), since its color was the same as MnO(2) and, like the latter, it was readily soluble in HCl with the evolution of chlorine. The amount of O(2) consumed in the oxidation of Mn(++) was 63% or more of theoretical. The ability of the cells to oxidize Mn(++) was destroyed by heating the cells at 93 C for 5 min. Only cell suspensions prepared from cultures of S. discophorus grown with MnSO(4) were able to oxidize Mn(++). It was concluded that the oxidation of manganous ions by S. discophorus is catalyzed by an inducible enzyme(s).