The mature biofilm produced
by FBR 4 was resistant to DNase treatment, suggesting that the matrix
contains other structural components and/or that eDNA was not
accessible to the DNase. Fluorescent microscopy of the FBR 4 biofilm revealed
that the biofilm was not disturbed after the DNase treatment,
but the matrix could be stained with propidium iodide suggesting that
eDNA was present in the biofilm. For strains FBR 1, FBR 2 and FBR 6 the
CV staining was belowdetection limit, but also here DNase and Proteinase
K treatments reduced the number of biofilm associated cells, with the latter
treatment showing the largest effect.