Biofilms

• Biofilm


  • Often characterized by the presence of flagellae
  • Usually embedded in a "slimy" matrix
  • Unusually resistant to antibiotics
  • Often present a problem in water treatment plants
• Biofilms


  • Spatially and metabolically structured microbial communities embedded in a self-produced extracellular polymer matrix (EPS) and located at a phase interface
  • Aggregates of microorganisms - are adherent to each other and/or a surface
  • One of the most widely distributed and successful modes of life on Earth
  • 95 – 99% of microorganisms exist in biofilms
  • Pure culture studies – not suitable for microbial ecology studies and biogeochemical cycling
  • Differentiate between free-living individuals (planktonic) and fixed biofilm (sessile) cells
• Interphase boundaries


  • Liquid (aqueous) – solid surface
  • Liquid - air
  • Between 2 immiscible liquids
  • Solid surface - air
• Biofilms


  • Primarily at liquid-solid interphases
  • Drive biogeochemical cycling processes of most elements in water, soil, sediment and subsurface environments
• Biotechnological applications of biofilms

  Filtration of drinking water, the degradation of wastewater and solid waste, and biocatalysis in biotechnological processes, such as the production of bulk and fine chemicals, as well as biofuels
• All higher organisms, including humans - colonized by microorganisms that form biofilms
• Biofilms are associated with persistent infections in plants and animals, including humans, and with the contamination of medical devices and implants
• Biofilms are responsible for biofouling and contamination of process water, deterioration of the hygienic quality of drinking water and microbially influenced corrosion
• Beneficial biofilms


  • Affect turbidity, taste, and odor
  • Red (iron) and black (manganese) in water
  • Increased frictional resistance
  • Pipe corrosion
  • Failure to meet water quality criteria
• Biofilms are the default way that microorganisms prefer to grow
• We find both beneficial and harmful biofilms – in nature and in clinical context, respectively
• Microbial cells within biofilms exhibit altered phenotypes compared to their planktonic counterparts, including increased resistance to antimicrobials and host immune responses.