BIOFILM DISPERSAL · Microbial persuasion: cross-species triggering of biofilm dispersal as a competitive strategy in marine Bacilli

The predominant mode of growth of bacteria in the natural environment is in biofilms. Although biofilm formation can be advantageous for bacteria, it has also some disadvantages, such as limited migration to an environment with fewer competitors or more nutrients. It is therefore not surprising that bacteria are not only form biofilms, but also are able to actively escape from the biofilm, a process called dispersal. Furthermore, in a competition between species, the production of signalling molecules that can actively induce the biofilm dispersal pathway of the competitors has evolved. In preliminary work, we observed that mature biofilms of a marine Micrococcus luteus strain and Escherichia coli could be dispersed by metabolites from a growing biofilm culture of a marine Bacillus licheniformis isolate. These results suggest that the dispersal of the M. luteus and E. coli biofilm may be an inducible, physiologically mediated process. This proposal aims to identify the compounds produced by the marine B. licheniformis EI-34-6, which brings about dispersal of the M. luteus and E. coli biofilms, and genes required for biosynthesis of these BDCs. Furthermore, we want to study the biofilm dispersal process on a single cell level using confocal scanning laser microscopy.