E van Hullebusch et al 2009 J. Phys.: Conf. Ser. 190 012184 doi:10.1088/1742-6596/190/1/012184
E van Hullebusch1, S Rossano1, F Farges2,3, M Lenz4, J Labanowski5, P Lagarde6, A-M Flank6 and P Lens7,8
Show affiliationsSulfur is an essential biological element, yet its biochemistry in anaerobic biofilm is poorly understood because there are few tools for studying this element in biological systems. X-ray absorption spectroscopy provides a unique approach to determining the chemical speciation of sulfur in intact biological samples. When treating sulfate containing wastewaters in full scale up-flow anaerobic sludge bed bioreactors, microbial activity forms biofilms, consisting of a complex mixture of cells and associated extracellular substances as well as undefined inorganic precipitates. In addition to the anaerobic sludges, a large variety of model compounds of S (esp. sulfides) were investigated to find consistencies in the XANES that were used to model each "valence state" of S. The results confirmed that attributing a specific valence to most sulfides is impossible as we measured a continuum of edge shifts from sulfur "-2" to "-1", depending on the electronic structure of S in the probed sulfides. In the sludges, various sulfur hot spots were probed for speciation, despite photo-reduction was sometimes a problem. First, we index the main features of complex K-edge XANES spectra for S2--type units and sulfate units. Organic sulfur compounds were also shown to contribute significantly to the sulfur species present in some anaerobic granular sludge.
87.80.-y Biophysical techniques (research methods)
87.64.-t Spectroscopic and microscopic techniques in biophysics and medical physics
Issue 1 (2009)
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