Mössbauer study of the reduction of synthesized ferrihydrite by the alkaliphilic iron-reducing bacterium Fuchsiella ferrireducens

Samples of biogenic iron minerals obtained during the growth of the anaerobic alkaliphilic ironreducing bacterium Fuchsiella ferrireducens (strain Ζ-7101 Т ) in the presence of synthesized ferrihydrite used as electron acceptor are studied by 57 Fe Mössbauer spectroscopy. Two series of samples, differing by electron acceptor, are analyzed. Ethanol and acetate are used as electron donors in the first and second series, respectively. Mössbauer studies are performed at room temperature and at 82 K. Phases containing ferrous iron (siderite) form in both series, while a magnetically ordered phase (a mixture of hematite and maghemite particles) forms only in the series with ethanol.