Before revision:  The anomalous diffusion of particles in the biofilm is described by a fractional subdiffusion-absorption equation  .
After revision:  The idea of this model is: We deduce details of the diffusion process in a medium in which direct experimental study is difficult, based on probing diffusion in external regions. Since a biofilm has a gel-like consistency, we suppose that subdiffusion of particles in the biofilm is described by a fractional subdiffusion-absorption equation .