Fluorescence spectroscopy and molecular weight distribution of extracellular polymers from full-scale activated sludge biomass

M. Esparza-Soto, Paul Westerhoff

Research output: Contribution to journalArticle

41 Scopus citations


Two fractions of extracellular polymer substances (EPSs), soluble and readily extractable (RE), were characterized in terms of their molecular weight distributions (MWD) and 3-D excitation-emission-matrix (EEM) fluorescence spectroscopy signatures. The EPS fractions were different: the soluble EPSs were composed mainly of high molecular weight compounds, while the RE EPSs were composed of small molecular weight compounds. Contrary to previous thought, EPS may not be considered only as macromolecular because most organic matter present in both fractions had low molecular weight. Three different fluorophore peaks were identified in the EEM fluorescence spectra. Two peaks were attributed to protein-like fluorophores, and the third to a humic-like fluorophore. Fluorescence signatures were different from other previously published signatures for marine and riverine environments. EEM spectroscopy proved to be a suitable method that may be used to characterise and trace organic matter of bacterial origin in wastewater treatment operations.

Original languageEnglish (US)
Pages (from-to)87-95
Number of pages9
JournalWater Science and Technology
Issue number6
StatePublished - May 28 2001



  • EEMs
  • EPS
  • Extracellular polymeric substances
  • Fluorescence spectroscopy
  • Humic substances
  • Molecular weight distribution

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology

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