Sorption of Heavy Metals (Pb, Cd, Co, and Zn) by Bacteria of the Genus Bacillus: An Investigation of the Ability and Consequences of Bioaccumulation

The concentrations of heavy metal salts (Pb, Cd, Co, and Zn), which have an inhibitory effect on the growth of Bacillus bacteria, were determined using the method of successive dilutions. The dynamics of changes in the pH of the nutrient medium during bacterial cultivation with metal salts were analyzed. Bacterial growth phases were identified before and after exposure to minimally suppressive concentrations of these heavy metals. Atomic adsorption analysis was used to measure the amount of Zn, Co, Cd, and Pb accumulated by the bacteria from the medium. Both the supernatant and the biomass were analyzed at the onset of the stationary phase of microorganism growth. The effect of these elements on the morphology of bacteria was investigated using atomic force microscopy, and FTIR spectroscopy revealed differences in the shape of metals accumulated by bacteria.