Exopolysaccharides of the Biofilm Matrix: A Complex Biophysical World

Microbial biofilm development is observed on virtually all submerged surfaces in natural and industrial environments. Biofilms are also observed at interfaces as pellicles, or in the bulk of aquatic environments as flocs or granules [1, 2]. A biofilm is a complex structure made of aggregates of microbial cells within a matrix of extracellular polymeric substances (EPS) (Figure 1). The matrix structure constitutes the elastic part of the biofilm. Interstitial voids and channels separating the microcolonies contain a liquid phase, mainly constituted by water. This liquid phase is the viscous part of the biofilm. The EPS matrix provides the biofilm with mechanical stability through these viscoelastic properties [3].