Effects of salt concentration on the intracellular cadmium content and the cadmium uptake by a highly cadmium-tolerant, moderately halophilic Pseudomonas sp
1993
Kobayashi, T. (Kagoshima Univ. (Japan). Faculty of Agriculture) | Tokunaga, H. | Seki, K. | Onishi, H.
The intracellular cadmium (Cd) content was measured with early stationary phase cells of a highly Cd-tolerant moderately halophilic bacterium Pseudomonas sp. No.40 cultivated in 1 M and 3 M NaCl medium containing 0 to 2500 mug of CdCl2/ml. It was found that the Cd contents were greatly affected by the NaCl concentration of the medium. When the bacterium was cultivated in the 1, 2, 3, and 4 M NaCl medium containing 1500mug of CdCl1/ml, the intracellular Cd content was 25.0, 4.1, 3.1, and 2.0 mg Cd per g of dry cells, respectively. The intracellular Cd content decreased with increases of NaCl concentration of the medium. The fact seems to reflect Cd-tolerance of the bacterium towards the growth in the medium of different NaCl concentration. It is worthwhile to note that the bacterium showed the highest Cd-tolerance (in 3 M NaCl) and the lowest Cd content among the bacteria so far known. The bacterial cells grown in the 1 M NaNO3 and 1 M Na2SO4 medium accumulated 1.8 - 1.3 times as much Cd(2+) as those in the 1 M NaCl medium in the presence of 50-200mug of CdCl1/ml. It would also explain the difference in the Cd toxicity in the medium of NaNO3, Na2SO4, or NaCl
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