Characterization of extracellular polymeric substances in the biofilms of typical bacteria by the sulfur K-edge XANES spectroscopy
Huirong Lin , Chengsong Ye , Lu Lv , Clark Renjun Zheng , Shenghua Zhang , Lei Zheng , Yidong Zhao , Xin Yu
DOI:10.1016/j.jes.2014.05.045
Received September 04, 2013,Revised January 13, 2014, Accepted , Available online August 28, 2014
Volume 26,2014,Pages 1763-1768
A combined approach of physicochemical extraction and sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy was applied to characterize the extracellular polymeric substances (EPS) of typical bacterial biofilms in this study. Physicochemical analysis showed variation of the contents of DNA, polysaccharide and protein in different fractions of EPS in different mediums. The sulfur K-edge XANES analysis yielded a variety of spectra. Spectral fitting of the XANES spectra utilizing a large set of model compounds showed that there was more reduced sulfur in both LB-EPS (loosely bound EPS) and TB-EPS (tightly bound EPS) of all the biofilms in LBmediumthan in R2Amedium. More oxidized sulfur was identified in LB-EPS than that in TB-EPS, suggesting different niches and physiological heterogeneity in the biofilms. Our results suggested that the sulfur K-edgeXANES can be a useful tool to analyze the sulfur speciation in EPS of biofilms.
