World Journal of Microbiology and Biotechnology

, Volume 11, Issue 5, pp 481–485 | Cite as

Electron microscopic examination of the extracellular polymeric substances in anaerobic granular biofilms

  • F. A. MacLeod
  • S. R. Guiot
  • J. W. Costerton


Scanning electron microscopy revealed that collapsed extracellular polymeric substances (EPS) surrounded bacteria present in granular sludge. Treatment of granular sludge with whole-cell antiserum and staining with polycationic ferritin demonstrated that bacteria were enveloped by extensive EPS. Antibody stabilization permitted a visualization of the EPS which more closely resembled its natural hydrated state. The EPS was seen to completely fill the intercellular spaces in the microcolonies. Both pure and mixed microcolonies were observed to be enclosed by EPS. The presence of these large amounts of EPS indicates that this extracellular layer is important in maintaining the structural integrity of granular sludge.

Key words

Anaerobic granule electron microscopy extracellular polymeric substances 


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Copyright information

© Rapid Science Publishers 1995

Authors and Affiliations

  • F. A. MacLeod
    • 1
  • S. R. Guiot
    • 2
  • J. W. Costerton
    • 3
  1. 1.Centre for Mineral and Energy TechnologyNatural Resources CanadaOttawaCanada
  2. 2.Biotechnology Research InstituteNational Research CouncilMontréalCanada
  3. 3.Centre for Biofilm EngineeringMontana State UniversityBozemanUSA

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