Document Detail


XAS analysis of a nanostructured iron polysaccharide produced anaerobically by a strain of Klebsiella oxytoca.
MedLine Citation:
PMID:  22585084     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
A strain of Klebsiella oxytoca, isolated from acid pyrite-mine drainage, characteristically produces a ferric hydrogel, consisting of branched heptasaccharide repeating units exopolysaccharide (EPS), with metal content of 36 wt%. The high content of iron in the EPS matrix cannot be explained by a simple ferric ion bond to the sugar skeleton. The bio-generated Fe-EPS is investigated by X-ray absorption spectroscopy. Fe K-edge XANES analysis shows that iron is mostly in trivalent form, with a non-negligible amount of Fe(2+) in the structure. The Fe EXAFS results indicate that iron in the sample is in a mineralized form, prevalently in the form of nano-sized particles of iron oxides/hydroxides, most probably a mixture of different nano-crystalline forms. TEM shows that these nanoparticles are located in the interior of the EPS matrix, as in ferritin. The strain produces Fe-EPS to modulate Fe-ions uptake from the cytoplasm to avoid iron toxicity under anaerobic conditions. This microbial material is potentially applicable as iron regulator.
Authors:
Iztok Arčon; Oreste Piccolo; Stefano Paganelli; Franco Baldi
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-5-15
Journal Detail:
Title:  Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine     Volume:  -     ISSN:  1572-8773     ISO Abbreviation:  -     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-5-15     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9208478     Medline TA:  Biometals     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
University of Nova Gorica, Vipavska 13, 5000, Nova Gorica, Slovenia, iztok.arcon@ung.si.
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