Microbial transformation of metals in relation to the biogeochemical cycle

Microbial transformations and interactions with metals are reviewed in relation to the biogeochemical cycle. Different strategies have been developed by microorganisms to cope with essential and toxic metals. The molecular mechanisms of metal resistance and metal transport are well known from the results of recombinant DNA analysis, sequencing and identification of the protein components involved in regulatory and membrane functions. Other mechanisms of metal interactions have only been studied at physiological level. The bioaccumulation of metals is discussed especially biological mineralization, in which bacteria are the nucleation sites for authigenic mineral formation in the environment. The environmental importance of the opposite process, namely mineral ore oxidation due to the biological leaching of metals from the ore reserve pool is also discussed. -Author