Identification and characterization of a novel acidotolerant Fe(III)-reducing bacterium from a 3,000-year-old acidic rock drainage site

Acidic, ochre-precipitating springs at Mam Tor, East Midlands, UK, are analogous to sites impacted by acid mine drainage over prolonged periods of time, and were studied for the presence of Fe(III)-reducing bacteria. From enrichment cultures inoculated with Mam Tor sediment, a facultative anaerobe capable of reducing Fe(III) at pH values as low as three was isolated. 16S rRNA gene analysis showed that this bacterium is a close relative of Serratia species and not previously shown to respire using Fe(III) as an electron acceptor. Direct cell counts of the isolate grown with Fe(III)-NTA coupled with protein assays suggest that this bacterium is able to conserve energy for growth through Fe(III) reduction.