Heavy metal particle resistance in Thiobacillus intermedius 13-1 isolated from corroded concrete

Abstract

The effect of exposure to heavy metal particles on the growth and survival of bacterial cells was investigated. Thiobacillus intermedius 13-1, Escherichia coli JM109, and Agrobacterium radiobacter IFO12665b1 were cultured on LB solid medium or in 5 ml of liquid medium containing 0.03 or 0.1 g respectively of the heavy metals, aluminum, cadmium, iron, lead, molybdenum, nickel, and zinc. Cadmium, nickel and zinc strongly inhibited cell growth in the three strains. In contrast, the bacterial cells were not inhibited by aluminum, iron, or lead in the solid or liquid medium. When these bacteria were exposed to heavy metals by vigorous shaking for 10 min, lead and molybdenum, but not nickel and zinc, were markedly toxic to the bacterial cells. Different reaction were thus observed under low-level, long-term and high-level, short-term exposure conditions. T. intermedius showed more resistance to zinc and nickel, and was more sensitive to molybdenum exposure, than E. coli and A. radiobacter.