摘要：The eastern wetlands of Kolkata have been reservoirs of some of the most unique metal tolerant bacteriathat have inexplicable bioremediation potentialities in immobilizing radionuclides and toxic metals, in thedegradation of oil, as a bioleaching agent, and in chelating zinc in living systems. Four bacterial strains wereisolated from mixed sewage and designated as L4(1), L4(2), L4(3) and L4(4). Gram staining was performedto determine the Gram nature and morphology of the strains. All were found to be Gram negative cocco-bacilli in character. The IMViC biochemical tests were performed for the characterization of the strains.Further, the L4(4) strain was found to grow on Eosin Methylene Blue agar medium, thereby indicating it to beof coliform origin. Different concentrations of zinc solutions i.e., 100ppm, 500ppm and 1000 ppm wereprepared in which each of the four strains were inoculated, and incubated at 37°C for 4 days. The bacterialgrowth was measured spectrophotometrically at 610nm. Atomic absorption spectroscopy analysis wasperformed to determine the uptake of zinc from the medium. Maximum uptake at 1000 ppm concentration ofzinc was observed by strain L4(4) [954.7 mg/L] and least by strain L4(1) [896mg/L]. At 500ppm concentrationof zinc, maximum uptake was observed by the strain L4(3) [464.7mg/L], and minimum by the strain L4(4)[442.7mg/L]. L4(4) was identified to be Escherichia coli. L4(3) having maximum uptake at 500ppmconcentration was identified with the help of 16S rDNA analysis and was found to be Pseudomonaspseudoalcaligenes. This organism on one hand acts as a potential source of zinc to fishes thereby acting asa probiotic. We project this organism for future treatment of marine oil spills, and it can be considered as onestop remedy for different kinds of marine pollution.
