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Background
• Biofilm: community of microorganisms
attached to a surface
• Biofouling: the process by which unwanted
material accumulates on a surface
Extracellular Polymeric Substance
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Composition of EPS synthesized varies from microbe to microbe
Functional role in microbial survival i.e. adhesion, protection
Critical for the structure and survival of the biofilm
Determines the micro-habitat of the cells within the biofilm
Influenced by the surrounding environment
Flemming, 2011
Extracellular Polymeric Substance
• EPS of microbial origin are a complex mixture of biopolymers comprising
polysaccharides, proteins, nucleic acids, uronic acids, humic substances,
lipids…
• Bacterial secretions
• Shedding of cell surface materials
• Cell lysates
• Adsorption of organic constituents from
the environment
result in EPS formation in a wide variety of
free-living bacteria as well as microbial
aggregates like biofilms, bioflocs and
biogranules.
Pal & Paul, 2008
Biofilm formation
Vogeleer et al., 2014
• EPS has a role in all parts of biofilm formation
– Aids in the adhesion to surfaces
– Formation of complexes
– Dissolution of the biofilm
Limoli et al, 2015
Transparent exopolymer particles
• Sub group of extracellular polymeric
substance
• Organic microgels of various sizes
• Present in marine and fresh water
• Colonised by microorganisms
• Naturally produced by phytoplankton and
bacteria.
TEP stained with alcian blue
Bar-zeev et al, 2012
Bar-zeev et al, 2012
Role of EPS & TEP in biofouling
Bar-Zeev et al., 2015
References
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Bar-Zeev, E., Berman-Frank, I., Girshevitzb, O., Berman, T., 2012, Revised paradigm
of aquatic biofilm formation facilitated by microgel transparent exopolymer
particles, PNAS, 109: 9119 – 9124.
Bar-Zeev, E., Passow, U., Castrillon, S. R-V., Elimelech, M., 2015, Transparent
Exopolymer Particles: From Aquatic Environments and Engineered Systems to
Membrane Biofouling, Envir. Sci. & Tech., 49: 691 – 707.
Flemming, H. C. 2011. The perfect slime, Colloids and Surfaces B: Biointerfaces, 86:
251 – 259.
Limoli, D.H., Jones, C. J., Wozniak, D. J., 2015, Bacterial extracellular
polysaccharides in biofilm formation and function, Microbiol. Spectrum, 1 – 19.
Pal, A., Paul, A.K., 2008, Microbial extracellular polymeric substances: central
elements in heavy metal bioremediation, Indian J. Microbiol., 48:49–64.
Vogeleer, P., Tremblay, Y. D. N., Mafu, A. A. Jacques, M., Harel, J., 2014,
Life on the outside: role of biofilms in environmental persistence of Shiga-toxin
producing Escherichia coli, Frontiers in microbiol., 5: 1 – 12.