Institute of Functional Interfaces

Natural and model biofilms on surfaces

Biofilmbild Homepage SchwartzKIT/IFG

Bacteria are perfectly adapted to their constantly changing environment and possess an enormous genetic potential that leads to a variety of stress reactions. These molecular reactions and adaptation processes guarantee the survival of the bacteria in the respective habitat and, in the case of pathogenic bacteria, also in the host organism. This ability to survive even under non-optimal conditions plays an important role in the medical field, in the food industry and in technical processes, which has only been realised in recent years. As a result, new elimination methods for pathogenic/resistant microorganisms are being developed and tested for use in technical processes. Stress reactions of bacteria are specifically investigated. They serve to repair the cell damage caused or to counteract damaging agents. Taxonomic and functionally relevant genes and their transcripts involved in such processes are quantitatively detected and used for the biological evaluation of the processes. 


Biofilms are bacterial cell assemblies of microorganisms on surfaces of natural systems and materials and are therefore ubiquitously present in the environment. As biological filters, they can be part of large-scale treatment processes. They remove dissolved, biodegradable substances from the environment, transform or mineralize them and form locally immobilized biomass. However, biofilms also represent a reservoir of germs, from which contamination with hygienically relevant bacteria can possibly arise.

For population analysis, molecular biological methods provide information about the composition of the biofilms, as well as their spatial and temporal variability. Target molecules in these techniques include regions in the genome (e.g. rDNA), which are present in all organisms regardless of their physiological status. With the help of molecular biological analysis methods, developmental stages of the biofilms can be identified by the expression of specific genes in the bacteria involved. Even bacteria that can no longer be cultivated, but are still alive and capable of reproduction, can be detected.

The influence of natural materials or modified surfaces on biofilms is investigated in different research approaches. In cooperation with various working groups from the BioInterface program and other KIT working groups, the modification of surfaces and their influence on biofilm growth is investigated.



Natural biofilms after staining with the DNA-binding fluorochrome Syto9 (left; A. Rieder, IFG) and ESEM image (right; F. Friedrich, IFG)