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XAS analysis of a nanostructured iron polysaccharide produced anaerobically by a strain of Klebsiella oxytoca

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Abstract

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 Fe2+ 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.

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References

  • Arčon I, Mozetič M, Kodre A (2005) XAS study of oxygen-plasma treated micronised iron-oxide pigments. Vacuum 80:178–183

    Article  Google Scholar 

  • Arčon I, Kolar J, Kodre A, Hanžel D, Strlič M (2007) XANES analysis of Fe valence in iron gall inks. X-Ray Spectrom 36:199–205

    Article  Google Scholar 

  • Baldi F, Minacci A, Pepi M, Scozzafava A (2001) Gel sequestration of heavy metals by Klebsiella oxytoca isolated from iron mat. FEMS Microbiol Ecol 36:169–174

    Article  PubMed  CAS  Google Scholar 

  • Baldi F, Marchetto D, Battistel D, Daniele S, Faleri C, De Castro C, Lanzetta R (2009) Iron-binding characterization and polysaccharide production by Klebsiella oxytoca strain isolated from mine acid drainage. J Appl Microbiol 107:1241–1250

    Article  PubMed  CAS  Google Scholar 

  • Baldi F, Marchetto D, Zanchettin D, Sartorato E, Paganelli S, Piccolo O (2010) A bio-generated Fe(III)-binding exopolysaccharide used as new catalyst for phenol hydroxylation. Green Chem 12:1405–1409

    Article  CAS  Google Scholar 

  • Coe EM, Bowen LH, Speer JA, Wang Z, Sayers DE, Bereman RD (1995) The recharacterization of a polysaccharide iron complex (Niferex). J Inorg Biochem 58:269–278

    Article  PubMed  CAS  Google Scholar 

  • Dominko R, Sirisopanaporn C, Masquelier C, Hanzel D, Arčon I, Gaberscek M (2010) On the origin of the electrochemical capacity of Li2Fe0.8Mn0.2SiO4. J Electrochem Soc 157:A1309–A1316

    Article  CAS  Google Scholar 

  • Küzma M, Dominko R, Hanzel D, Kodre A, Arčon I, Meden A, Gaberscek M (2009) Detailed in situ investigation of the electrochemical processes in Li2FeTiO4 cathodes. J Electrochem Soc 156:A809–A816

    Article  Google Scholar 

  • Leone S, De Castro C, Parrilli M, Baldi F, Lanzetta R (2007) Structure of the iron-binding exopolysaccharide produced anaerobically by the gram-negative bacterium Klebsiella oxytoca BAS-10. Eur J Org Chem 31:5183–5189

    Article  Google Scholar 

  • Ravel B, Newville M (2005) ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT. J Synchrotron Radiat 12:537–541

    Article  PubMed  CAS  Google Scholar 

  • Rehr JJ, Albers RC, Zabinsky SI (1992) High-order multiple-scattering calculations of x-ray-absorption fine structure. Phys Rev Lett 69:3397–3400

    Article  PubMed  CAS  Google Scholar 

  • Watt RK (2011) The many faces of the octahedral ferritin protein. Biometals 24:489–500

    Article  PubMed  CAS  Google Scholar 

  • Wong J, Lytle FW, Messmer RP, Maylotte DH (1984) K-edge absorption spectra of selected vanadium compounds. Phys Rev B 30:5596–5610

    Article  CAS  Google Scholar 

Download references

Acknowledgments

This research was supported by the Slovenian Research Agency (P1-0112). Access to synchrotron radiation facilities of ELETTRA (beamline XAFS) is acknowledged. Giuliana Aquilanti and Luca Olivi of ELETTRA are acknowledged for expert advice on beamline operation.

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Correspondence to Iztok Arčon.

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Arčon, I., Piccolo, O., Paganelli, S. et al. XAS analysis of a nanostructured iron polysaccharide produced anaerobically by a strain of Klebsiella oxytoca . Biometals 25, 875–881 (2012). https://doi.org/10.1007/s10534-012-9554-6

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  • DOI: https://doi.org/10.1007/s10534-012-9554-6

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