20.500.12556/RUNG-3004-5ba07d23-9418-50e3-4a4b-24546cf64098
An extracellular polymeric substance quickly chelates mercury(II) with N-heterocyclic groups
A strain of Klebsiella oxytoca DSM 29614 is grown on sodium citrate in the presence of 50 mg l−1 of Hg as Hg(NO3)2. During growth, the strain produces an extracellular polymeric substance (EPS), constituted by a mixture of proteins and a specific exopolysaccharide. The protein components, derived from the outer membrane of cells, are co-extracted with the extracellular exopolysaccharide using ethanol. The extracted EPS contains 7.5% of Hg (total amount). This indicates that EPS is an excellent material for the biosorption of Hg2+, through chemical complexation with the EPS components. The binding capacity of these species towards Hg2+ is studied by cyclic voltammetry, and Hg L3-edge XANES and EXAFS spectroscopy. The results found indicate that Hg2+ is mainly bound to the nitrogen of the imidazole ring or other N-heterocycle compounds. The hydroxyl moities of sugars and/or the carboxyl groups of two glucuronic acids in the polysaccharide can also play an important role in sequestring Hg2+ ions. However, N-heterocyclic groups of proteins bind Hg2+ faster than hydroxyl and carboxyl groups of the polysaccharide.
Klebsiella oxytoca
Biosorption
Proteins
Polysaccharide
Cyclic voltammetry
EXAFS analysis
true
true
false
Angleški jezik
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Delo ni kategorizirano
2017-03-03 10:23:11
2017-03-03 12:18:07
2023-06-09 03:19:55
0000-00-00 00:00:00
2017
0
0
10
February 2017
2017
0000-00-00
PostprintKoncna
NiDoloceno
NiDoloceno
0000-00-00
0000-00-00
0000-00-00
4706811
10.1016/j.chemosphere.2017.02.093
URN:SI:UNG:REP:MUXZ5NMW
Univerza v Novi Gorici
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1
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