The biochemistry and genetics of microbial perchlorate reduction

Abstract

While regarded as a relatively new form of microbial metabolism, our understanding of the perchlorate reduction pathway has progressed dramatically in the last five years. Genetic analyses have offered the first glimpse into the enzyme encoding genes integral to perchlorate metabolism as well as putative regulation targets. This genomic analysis has also offered tools for detecting and monitoring dissimilatory perchlorate-reducing bacteria for bioremediative purposes. Mimicking the physiological diversity of these microorganisms, a surprising realm of genetic diversity has been discovered in the perchlorate reduction loci of dissimilatory perchloratereducing bacteria (DPRB). The perchlorate reduction pathway consists of two central enzymes: perchlorate reductase and chlorite dismutase (Fig. 1). The first enzymatic step of the pathway, perchlorate reduction to chlorite, is performed by perchlorate reductase. The toxic chlorite formed from this reduction is subsequently converted to chloride and oxygen by chlorite dismutase. Here we review the identification, analysis, and phylogenetic conservation of the genes encoding perchlorate reductase and chlorite dismutase based on the timeline of the respective discoveries, as well as their potential application in environmental biotechnology. © 2006 Springer Science+Business Media, Inc.