Accumulation of some heavy metals by metal resistant avirulent Bacillus anthracis PS2010 isolated from Egypt

Abstract

The bacteria with a high growth rate were isolated from polluted industrial waste water. The bacteria Bacillus anthracis PS2010 have variable resistant to heavy metals such as Cd, Cu, Co, Zn and Pb. Out of which the minimal inhibitory concentrations were 0.6, 2.0, 0.8, 4.0 and 3.0 mM, respectively. The potent bacterium has optimal biosorption capacity raised according to the metal, incubation temperature, pH of the solution and contact time. Under optimal conditions, the bacterium was capable of taking up the heavy metals Cd, Cu, Co, Zn and Pb at 3.41, 2.03, 4.75, 5.22 and 6.44 mg/g dry weight. Transmission electron microscopy showed accumulation of Pb metal external to bacterial cells. The mechanism of heavy metal tolerance in Bacillus anthracis PS2010 is chromosomally encoded. Bacillus anthracis harbored no plasmid.