Abstract

The redox cycling of metals by microorganisms has attracted recent interest as these transformations can play crucial roles in the cycling of both inorganic and organic species in a range of environments and, if harnessed, may offer the basis of a wide range of innovative biotechnological processes. These include the bioremediation of metal contaminated land and water, the oxidation of xenobiotics under anaerobic conditions, metal recovery in combination with the formation of novel biocatalysts, and even the generation of electricity from sediments. Under certain conditions, however, microbial redox cycling can also mobilise toxic metals with potentially calamitous effects on human health. Rapid advances over the last decade have resulted in a detailed understanding of some of these transformations at a molecular level, with added impetus expected from the imminent availability of complete genome sequences for key subsurface bacteria, in combination with genomic and proteomic tools.