Biofilms are environmentally relevant lifestyles of microorganisms. Usually, biofilms are isolated from surfaces or interfaces, where cells grow together, differentiate, and produce a matrix. This matrix also protects the microorganisms from environmental insults, such as antimicrobials and several other stress conditions. In our everyday life, biofilm formation and associated costs and benefits are encountered regularly as a source of contamination in food processing, reducing heat transfer in cooling towers, increase drag on ships, foul reverse osmosis membranes, or corrode metal surfaces. Since biofilms resist antimicrobial treatment, they are difficult to control in industry or, medically relevant, the clinics. Moreover, biofilm formation is required for biocontrol properties in plant protection, e.g. with soil inhabiting plant growth promoting microbes. Due to the remarkable resistance features associated with biofilms, inhibition or promotion of biofilm development receives substantial attention in both health sciences and biotechnology.