Incidence of Multiple Heavy Metal Resistance in a Bacillus Species

A new strain of Bacillus capable of growing upto pH 11 was isolated from a local pond polluted with detergents. This strain elicited unimpaired growth in media supplemented with heavy metals such as As, Cu, Cd, Hg, Ni and Zn. A MIC value of 200, 3, 1.60, 2.25, 7.50 and 3.70 mM was noticed for As, Cu, Cd, Hg, Ni and Zn respectively. Analysis of total DNA revealed the presence of a plasmid of 26 kb. This plasmid was lost by acriflavine treatment to the cultures. Such cured strains were found sensitive to heavy metals. Our findings suggest that incidence of heavy metal resistance is widely distributed and resistant strains could be isolated from heavy metal unpolluted sites.