Mercury Pollution and Bioremediation-A Case Study on Biosorption by a Mercury-Resistant Marine Bacterium

Mercury (Hg), a naturally occurring element with a widespread use in industry, is the most toxic of the heavy metals. Worldwide, many areas are polluted with mercury, presenting a threat to people and the environment, and thus need to be mitigated using proper methods, including bioremediation. Most of the environmental bacteria continuously exposed to mercury present in terrestrial and aquatic environments adopt the heavy metal genotype to survive in the toxic environment. In mer operon-mediated mercury resistance, the cumulative actions of certain functional genes, along with regulator, promoter, and operator, etc. convert the toxic forms of mercury to the relatively less toxic elemental form of mercury. However, certain mercury-accumulating strains of bacteria have also been reported binding mercury in their extracellular polymeric substances along with the cysteine residues of constituent proteins to confer resistance towards this toxic metal. Ongoing research continues aiming at understanding the non- mer operon-mediated mercury resistance mechanism in potent bacterial isolates and their role in bioremediation of mercury in contaminated environmental conditions. © 2014 Elsevier Inc. All rights reserved.