Oxidation of Manganese and Formation of Mn3O4 (Hausmannite) by Spore Coats of a Marine Bacillus sp

Isolated spore coats of a marine Bacillus species were incubated in 25 mM MnCl2 at pH 7.5. Manganese precipitates, formed on the coat surfaces, were analyzed by transmission electron microscopy, electron diffraction, and energy-dispersive X-ray spectroscopy. Initially, an amorphous manganese oxide was observed on the coats which recrystallized to hausmannite after prolonged incubation in the MnCl2 solution. The spore coats catalyze the oxidation of Mn(II) and have no structural influence on the final mineral phase precipitated.