Potential of anaerobic bacteria in bioremediation of metal-contaminated marine and estuarine environment

Metal contamination is increasing mainly due to the anthropogenic activities, and a major part of metals are finally deposited into the estuarine and marine environments. The stress of metal contamination enhanced the resistance mechanism of microorganisms in such environments and they can degrade the metals under specific conditions. This capability of microorganisms, especially bacteria, can be utilized for the bioremediation of metals. The present chapter discusses the fundamentals of bioremediation and role of bacteria especially anaerobic bacteria in the bioremediation of metals. The study identified and characterized a mercury-resistant anaerobic bacterium Paraclostridium bifermentans strain B1 from Cochin estuary. The isolated strain has the capability to remove (81%) and absorb (0.6 µg g−1) mercury in the form of HgCl2. P. bifermentans has the capacity to tolerate mercury. Furthermore, more attention shall be given to this mercury-resistant bacterial strain with a focus on bioremediation of mercury because compared with physical and chemical remedial measures, bioremediation is examined as the attainable remedial technology.