A biofilm is an association of microorganisms (e.g. algae, fungi, protozoa and bacteria) that adhere to each other and are encased by a matrix called an extracellular polymeric substance (EPS) or slime (“Biofilm”). The EPS is unique in that they have a network of open water channels and cell to cell interactions. This allows for intercellular communication, sharing of nutrients and exchange of genetic materials between cells in the biofilm (“Microbial Biofilms”). The relationship between microbial cells in the biofilm is very similar to that of a humans living in a city. They provide protection and share resources, all for the benefit of the many (Watnick and Kolter, 2000). The EPS in a biofilm provides protection from antibiotics, metal toxicity, salinity, UV exposure, etc. (“Microbial Biofilms”).
Biofilms adhere to both biotic (living) and abiotic (non-living) surfaces and also float in mats. Planktonic microbes scope out a surface or biofilm to join much the same way as we choose a city or neighborhood to live in. They become part of the community and share resources and communicate “rules” of being part of the community. If conditions change and it is no longer favorable for a microbe to be part of the community, it will detach from the biofilm and search out a new neighborhood (Watnick and Kolter, 2000).
Biofilms can play a positive role in breaking down organic matter and pollutants (including petroleum oil) and in nutrient cycling in the environment. However, they also have negative effects including corrosion of metals such as pipes and boat hulls and it is believed that biofilms are the cause of up to 80% of all microbial infections in humans (“Microbial Biofilms”). Common infections caused by biofilms include tooth decay, endocarditis, urinary tract infections, middle ear infections, sinusitis, just to name a few. They can be used for constructive reasons such as in sewage treatment plants and to remove oil spills from the marine environment (“Biofilm”).
Works Cited
"Biofilm." Wikipedia, The Free Encyclopedia, 18 Apr. 2013. Web. 5 June 2013.
“Microbial Biofilms.” Pacific Northwest National Laboratory, July 2010. Web. 5 June 2013.
Watnick, P. and Kolter, R. “Biofim, City of Microbes.” Journal of Bacteriology 182,10 (2000):2675-2679.
