Morphological and diffusional changes in L. lactis biofilms

Through their special way of life, biofilms have several advantages over organisms in planktonic growth. By being surface-attached and producing a mass of extracellular polymeric substances (EPS), microorganisms possess inherent self-immobilization, which decreases the expenditure of downstream processing in industrial applications. Furthermore, they are more resilient against environmental stress and toxic substances, such as antibiotics. An important factor here is diffusion, of substrate into the biofilm and metabolites through and out of the biofilm; however, these mechanisms are still poorly understood. By utilizing a specially developed diffusion model and CLSM FRAP microscopy, diffusion constants in the living, fully hydrated biofilm of L. lactis during development can be assessed. With it, heatmaps of diffusional constants and finally a diffusion profile encompassing a true 3D space of the living biofilm in growth can be generated. With those, possible hotspots and changes of diffusion inside the biofilm structure with regard to changing cultivation conditions and the substratum can be identified, thus furthering our understanding of diffusion in biofilms and how they react to their environment.

The project is funded by the DFG (UL 170/14-1) and the collaborative research center (SFB) 926 on “microscale morphology of component surfaces” (MICOS).