Bacteria do not live alone, but rather join together with other microorganisms to form a slimy coating – a so-called biofilm. A typical everyday example of a biofilm is tooth plaque. Here, a wide variety of bacteria come together to feed off leftover particles of food. However, biofilm structures can also be found in ground water, in soil and sediments, as well as on rocks.
The research group "Chemical Microbiology" focuses on characterizing these biofilms. The group analyzes not only microbial communities in the environment, some of which live in extreme habitats such as super salty lakes that at the same time may be very acid or alkaline, but also biofilms on pacemakers and tooth implants.
DNA is prepared from the different biofilms. Specific segments are copied, the products separated and ultimately sequenced. With the help of a data bank it is usually possible to conduct a taxonomic identification of the bacteria in the biofilm community.
However, we don't just want to find out who is living with whom, but also why the bacteria are interacting and what tasks each one is performing for the community. In pursuit of these questions we use substrates that, besides having normal carbon, are enriched with the stable carbon isotope C13. The bacteria use the marked substrate, extracting the isotope in many individual steps from the substrate, and insert it into new compounds; for example, fatty acids. Using a mass spectrometer, it can be determined in which molecular compound the isotope is. In this way, individual enzymatic steps can be precisely observed. The work group's expertise in this field is widely recognized.
