Biofilms are widely spread and appear on natural materials as well as industrial surfaces, pipes (Figure 1), production facilities and medical equipment and products due to the fact that most bacteria prefer a surface-associated existence. Microbial biofilms (Figure 2) develop when the microorganisms have become irreversibly attached to the surface which takes place after the initial adhesion step when extra-cellular polymers which favor adhesion are produced (Figure 3). The biofilm itself has a structure which is perfused with liquid. In environments which are low on nutrients, substrates are concentrated by polymeric substances. The polymeric matrix also protects the microorganisms which are organized in the biofilm against inactivating environmental conditions. Therefore elimination of biofilms is extremely difficult and removing them is very expensive.