Transformation of carbon tetrachloride by biogenic Fe(II)

The dissimilatory Fe(III)-reducing bacterium Shewanella alga, strain BrY reduced structural Fe(III) in layered silicates and Fe(III) in a variety of synthetic and natural crystalline Fe(III)-oxides. Reduction of Fe(III) in each compound supported growth of bacteria and provided Fe(II) that either remained bound in the clay lattice of the layered silicates or was adsorbed to the surfaces of the crystalline oxides. Bound and sorbed Fe(II) chemically degraded carbon tetrachloride under anoxic conditions, whereas soluble Fe(II) did not. Similar results were obtained using Hanford subsurface or Columbia River sediments that contained microbially-reduced Fe(II). Microbial reduction of Fe(III) to reactive Fe(II) provides potential for in situ degradation of carbon tetrachloride under anoxic conditions.