title: NMR and MALDI-TOF MS based characterization of exopolysaccharides in anaerobic microbial aggregates from full-scale reactors.
abstract: Anaerobic granular sludge is composed of multispecies microbial aggregates embedded in a matrix of extracellular polymeric substances (EPS). Here we characterized the chemical fingerprint of the polysaccharide fraction of EPS in anaerobic granules obtained from full-scale reactors treating different types of wastewater. Nuclear magnetic resonance (NMR) signals of the polysaccharide region from the granules were very complex, likely as a result of the diverse microbial population in the granules. Using nonmetric multidimensional scaling (NMDS), the (1)H NMR signals of reference polysaccharides (gellan, xanthan, alginate) and those of the anaerobic granules revealed that there were similarities between the polysaccharides extracted from granules and the reference polysaccharide alginate. Further analysis of the exopolysaccharides from anaerobic granules, and reference polysaccharides using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) revealed that exopolysaccharides from two of the anaerobic granular sludges studied exhibited spectra similar to that of alginate. The presence of sequences related to the synthesis of alginate was confirmed in the metagenomes of the granules. Collectively these results suggest that alginate-like exopolysaccharides are constituents of the EPS matrix in anaerobic granular sludge treating different industrial wastewater. This finding expands the engineered environments where alginate has been found as EPS constituent of microbial aggregates.
authors.affiliation: King Abdullah University of Science and Technology, Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Center. Thuwal 23955-6900, Saudi Arabia.|UNESCO-IHE, Westvest 7, 2611 AX Delft, the Netherlands.
authors.forename: Graciela
authors.initials: G
authors.lastname: Gonzalez-Gil
authors.affiliation: King Abdullah University of Science and Technology, Biosciences Core Laboratory, Thuwal, Saudi Arabia.
authors.forename: Ludivine
authors.initials: L
authors.lastname: Thomas
authors.affiliation: King Abdullah University of Science and Technology, Advanced Nanofabrication Imaging and Characterization, Thuwal, Saudi Arabia.
authors.forename: Abdul-Hamid
authors.initials: AH
authors.lastname: Emwas
authors.affiliation: UNESCO-IHE, Westvest 7, 2611 AX Delft, the Netherlands.
authors.forename: Piet N L
authors.initials: PN
authors.lastname: Lens
authors.affiliation: King Abdullah University of Science and Technology, Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Center. Thuwal 23955-6900, Saudi Arabia.
authors.forename: Pascal E
authors.initials: PE
authors.lastname: Saikaly
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D005110:Extracellular Space; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011134:Polysaccharides / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D012722:Sewage / Q000382:microbiology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods
chemical_list: D011134:Polysaccharides; D012722:Sewage