ABSTRACT
Marine environment is the most dynamic among the existing environmental conditions. The increase in mercury pollution in the Bay of Bengal, Odisha, India, has substantially increased the number of mercury-resistant marine bacterial (MRMB) population as observed in the study sites. Representative 25 isolates with distinguished colony morphology, 5 from each study sites, were characterized for their phenotypic and genotypic characteristics. The minimum inhibitory concentration (MIC) of the isolates was found to be in the range of 12.5–50 ppm. All the isolates were not only found to tolerate higher amounts of mercury but also showed resistance to other toxic metals such as Cd, Zn, Pb, As, and many antibiotics. Phenotypic mercury resistance in isolated MRMB revealed the mechanism of the resistance phenomenon. 36% and 28% of the screened isolates were found to resist mercury by mer operon–mediated volatilization and mercury biosorption mechanisms, respectively. However, in many isolates, the mercury-resistant genetic determinant could not be identified, and the novel search of which may provide many advantageous approaches to deal with the globally rising mercury pollution through bioremediation. In addition to that, volatilization of mercury by the isolates was found to be more effective than biosorption in terms of mercury removal by the isolates.
