Microorganisms and Metal Pollutants

Metals cannot be degraded through any physical, chemical or biological means, including microorganisms. However, microorganisms can alter the bioavailability of metals and their potential toxicity by changing the valence state of specific metals through oxidation or reduction. The goal of this chapter is to demonstrate how the presence of metals influences both the degree and type of microbial metal resistance mechanisms that are expressed, and how microbial resistance, in turn, can influence the fate of metals in the environment. First, metals and their interaction with the physicochemical components of the environment are discussed. Subsequently, we focus on specific metal-microbe interactions including: mechanisms of metal resistance; positive and negative effects of metal-microbe interactions; and applications of microorganisms in metal mining and remediation of metal-contaminated sites.