What exactly are Biofilms?
And why are they so problematic in our water systems.
You may not be familiar with the term “Biofilm,” but you will most certainly have come across Biofilms before.
The slippery slime on the rocks by a river, the “gunk” that clogs your drains and the plaque that forms on your teeth causing tooth decay – these are Biofilms. In water systems, biofilms are found on the inside of the water pipes, industrial cooling towers, heat exchangers, plumbing systems, etc.
Because of the biofilms’ complex architecture, stabilized by its attached mechanisms and ability to adapt to the environmental conditions, they are very difficult to re-move
“The reason that biofilm formation is a great cause of concern is that, within a biofilm, bacteria are more resistant to antibiotics and other major disinfectants that you could use to control them,” said A.C. Matin, a professor of microbiology and immunology at Stanford University.
Where can they be found and how are they formed?
Biofilm forms when bacteria adhere to surfaces in moist environments by excreting a slimy, glue-like substance.
They have been found growing on minerals and metals, underwater, underground and above the ground. They can grow on many different surfaces including plant tissues, animal tissues and on implanted medical devices such as catheters and pacemakers.
Wherever you find a combination of moisture, nutrients and a surface, you are likely to find biofilm.
Biofilms can adapt perfectly to the environmental conditions, making the disinfection process a difficult task.
A biofilm develops in five phases:
- Attachment to the surface – Reversible attachment
- Formation of the monolayer – This will produce an extracellular matrix or “slime” for protection causing irreversible attachment
- Aggregation – Microbial cells join the first attached microorganisms
- Maturation – Micro-organisms begin to multiply, with which the biofilm grows in a three-dimensional manner. Water channels form through and around biofilms, these channels serve, among other things, to get nutrients from the outside and eliminate metabolic waste products
- Detachment – Microbial cells detach from the initial biofilm and initiate the formation of another matrix on a new surface.