Removal of cadmium by Halobacterium strain R1 MTCC 3265 from saline and non-saline econiches

Abstract

Haloarchaeon Halobacterium strain R1 MTCC 3265 is an attractive candidate for use in bioremediation due to its resistance to 4 mM cadmium (Cd) in nutrient rich medium NTYE (25 percent NaCl Tryptone Yeast extract) and up to 2 mM Cd in synthetic medium NGSM (20 percent NaCl glucose synthetic medium) containing 0.2 percent glucose as sole source of carbon. The cells accumulated a maximum of 18 ppm of Cd on the 5th day of growth. In line with its true haloarchaeal nature the cells of Halobacterium strain R1 lysed on suspension in distilled water or media containing low NaCl concentrations. As such this strain cannot be used for the removal of metal from non-saline environments. However to overcome this problem cells were immobilised in calcium alginate. The immobilized cells were viable and could efficiently remove up to 63 percent Cd from deionized water.