Invisible protective shields of microorganisms

Biofilms are everywhere, whether on our teeth, in sewage systems, or on medical implants. They are complex communities of microorganisms that attach themselves to surfaces and are surrounded by a protective layer of mucus. These structures are highly organized and have amazing protective mechanisms.

What exactly is a biofilm?

A biofilm is a collection of microorganisms, mainly bacteria, embedded in a self-produced matrix of extracellular polymeric substances (EPS). This matrix consists mainly of polysaccharides, proteins, lipids, and DNA. It serves both to hold the microbial community together and to protect it.
Biofilms can form on both biological and non-living surfaces. Examples include tooth surfaces, contact lenses, water pipes, food packaging, and water tanks.

How does a biofilm form?

The formation of a biofilm proceeds in several phases and results in a cycle.

1. Adhesion:
Individual microorganisms attach themselves to a suitable surface via specialized proteins or structures such as pili.
2. Colonization:
The cells begin to divide and communicate via quorum sensing molecules to coordinate their behavior.
3. Matrix formation:
The microorganisms produce the EPS matrix, which stabilizes and protects the biofilm.
4. Maturation:
Complex three-dimensional structures develop. These have channels for nutrient transport, which are comparable to primitive tissue.
5. Detachment:
Parts of the biofilm or individual cells detach to colonize new locations.

What protective functions does the biofilm offer?

The EPS matrix is much more than just “slime.” It acts as a protective shield against external influences.

Bacteria in biofilm are often up to 1000 times more resistant to antibiotics than free-floating (planktonic) cells. Reasons for this include the limited penetration of active substances, altered metabolic states of the bacteria, and genetic adaptations.

• Protection from the immune system:
  Immune cells find it much more difficult to recognize and fight biofilm structures.
• Resistance to environmental stress:
  Biofilms offer protection against UV radiation, pH fluctuations, disinfectants, and dehydration.
• Communication and cooperation:
  Through quorum sensing, microorganisms in the biofilm can develop joint defense strategies.

Why are biofilms a problem?

Biofilms often form in industrial and domestic water pipes, where they adhere to the inner walls of the pipes. These biofilms are not only problematic from a hygienic point of view but also have technical and economic consequences.

On the one hand, they promote the growth of pathogens such as Legionella pneumophila or Pseudomonas aeruginosa, which can detach from the biofilm and spread through the water. At the same time, corrosion, pipe blockages, and increased energy consumption can occur as the flow is impeded. In addition, biofilms are difficult to remove because they are extremely resistant to certain disinfectants and many cleaning methods.



An often underestimated factor is water temperature: many microorganisms grow particularly well in the range of 20–50 °C, which is common in many hot water systems. Legionella bacteria in particular find optimal conditions here. In principle, temperatures above 60 °C kill germs, but the protective matrix of the biofilm can partially shield them from the heat. As a result, bacteria survive inside.

Summer heat as an additional risk

The problem can be exacerbated in summer. Standing water in rarely used pipes (e.g., schools, hotels, vacation homes) quickly heats up to critical temperatures in the pipes. These “warm zones” in the pipe system promote biofilm formation, especially if the water does not circulate for long periods of time. Legionella and other pathogenic germs can multiply rapidly in these warm, stagnant areas and be inhaled as aerosols the next time the water is used.

Conclusion: Biofilms – useful helpers with two faces

Not all biofilms are undesirable. In many natural and technical ecosystems, biofilms fulfill important tasks:


• Breakdown of organic pollutants in sewage treatment plants
• Promoting soil fertility and supporting plant growth
• Stabilizing the human intestinal flora

At the same time, however, certain biofilms can cause infections, material damage, or hygiene risks.

Hygienic safety ensured by Hydroliq WATER DISINFECTION Plus

Hydroliq Water Disinfection Plus offers an effective and sustainable solution for disinfecting drinking water and water pipes – without leaving any residues. It is easy to use, odorless, and can be easily integrated into existing systems. Our solution eliminates 99.99% of all germs, including Legionella. Continuous use breaks down biofilm and prevents recontamination. Hydroliq is approved for drinking water disinfection, certified (BAG, SVGW), and does not require any hazard symbols.




We would be happy to provide you with individual advice and ensure safe, germ-free water for you in the long term!

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