METAL-BINDING CHARACTERISTICS OF THE GAMMA-GLUTAMYL CAPSULAR POLYMER OF BACILLUS-LICHENIFORMIS ATCC-9945
METAL-BINDING CHARACTERISTICS OF THE GAMMA-GLUTAMYL CAPSULAR POLYMER OF BACILLUS-LICHENIFORMIS ATCC-9945
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DOI：
10.1128/aem.56.12.3671-3677.1990
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发表时间：
1990-12-01
影响因子：
4.4
通讯作者：
BEVERIDGE, TJ
中科院分区：
文献类型：
--
作者：
MCLEAN, RJC;BEAUCHEMIN, D;BEVERIDGE, TJ
The metal-binding affinity of the anionic poly-.gamma.-.DELTA.-glutamyl capsule of Bacillus licheniformis was investigated by using Na+, Mg2+, Al3+, Ca2+, Cr3+, Mn2+, Fe3+, Ni2+. Purified capsule was suspended in various concentrations of the chloride salts of of the various metals, and after dialysis the bound metals were analyzed either by graphite furnace atomic absorption spectroscopy or by inductively coupled plasma-mass spectrometry. Exposure of purified capsule to excess concentrations of Na+ revealed it to contain 8.2 .mu.mol of anionic sites per mg on the basis of Na binding. This was confirmed by titration of the capsule with HCl and NaOH. Other metal ions were then added in ionic concentrations equivalent to 25, 50, 75, 100, 200, and 400% of the available anionic sites. The binding characteristics varied with the metal being investigated. Addition of Cu2+, Al3+, Cr3+, or Fe3+ induced flocculation. These metal ions showed the greatest affinity for B. licheniformis capsule in competitive-binding experiments. Flocculation was not seen with the addition of other metal ions. With the exception of Ni2+ and Fe3+ all capsule-metal-binding sites readily saturated. Ni2+ had low affinity for the polymer, and its binding was increased at high metal concentrations. Fe3+ binding resulted in the development of rust-colored ferrihydrite which itself could bind additional metal. Metal-binding characteristics of B. licheniformis capsule appear to be influenced by the chemical and physical properties of both the cpsule and the metal ions.
