FIG. 3.

Estimation of metal content in P. putida KT2440 and HMR020 strains. Cultures of P. putida KT2440 and HMR020 strains were grown in LB until the exponential phase and then supplemented with 0.5 mM Cd²⁺, Zn²⁺, Ni²⁺, or Co²⁺. Cells were harvested after 12 h, and the pellet was suspended in Millipore water. Cellular metal was extracted by acid digestion procedure. The concentrations of Cd²⁺, Zn²⁺, Ni²⁺, and Co²⁺ were measured by atomic absorption spectroscopy.