Oxidative biotransformation of biotite and glauconite by alkaliphilic anaerobes: The effect of Fe oxidation on the weathering of phyllosilicates

摘要: Abstract Two alkaliphilic anaerobic bacteria, namely, the dissimilatory iron-reducer Geoalkalibacter ferrihydriticus and fermentative hydrolytic Clostridium alkalicellulosi, along with their co-cultures, are studied to examine ability release Si Fe from two main Fe-containing phyllosilicates in Earth's crust: biotite glauсonite. The formation of magnetically ordered phase(s) within 200 days incubation was only observed presence G. whether a mono- or co-culture but not abiotic controls pure culture C. alkalicellulosi. these organisms could represent simple trophic chain which alkalicellulosi decomposed microcrystalline cellulose produce organic acids ethanol, while ferrihydriticus, as we expected, utilized products reduces Fe(III) phyllosilicate lattices. Unexpectedly, did utilize instead produced an additional 3 mM acetate during growth phyllosilicates. An analysis Mossbauer spectra glauconite that were weathered revealed phases formed by Fe2+ oxidation rather than Fe3+ reduction. possible explanation this phenomenon be carbonate electron acceptor. Thermodynamic calculations show possibility such reaction. Thus, microorganisms respiratory metabolism play active role bioweathering under alkaline conditions. bacterial ferrous iron donor is supposed have played significant ancient environments, serving one causes banded formations.