How bacteria manage to breathe on rust

Abstract

Subsurface Microbes![Figure][1] The detoxifying bug Shewanella oneidensis (green) growing on crystals of hematite (brown). PHOTO: EMSL/FLICKR In the absence of oxygen, anaerobic bacteria turn to other chemical compounds during respiration. This can be helpful in detoxifying heavy-metal pollution. Flynn et al. (see the Perspective by Friedrich and Finster) found that alkaline conditions prevent a detoxifying bug— Shewanella oneidensis —from using enzymes to reduce rust-like minerals. Instead, the bacteria reduce elemental sulfur compounds, generating hydrogen sulfide that reduces the iron indirectly. This interplay between anoxic biogeochemical cycles may explain why some anaerobic bacteria contain the genetic machinery necessary to reduce multiple compounds besides oxygen. Science , this issue p. [1039][2]; see also p. [974][3] [1]: pending:yes [2]: /lookup/doi/10.1126/science.1252066 [3]: /lookup/doi/10.1126/science.1255442