The main function of the slime layer in bacteria is:
The slime layer is a diffuse, loosely attached glycocalyx composed largely of acidic heteropolysaccharides, proteins, and extracellular DNA that extends irregularly beyond the cell wall, differing from a well-defined capsule that remains tightly coupled to wall synthesis machinery. Because it is loosely associated, it can be easily washed away in laboratory preparations but in nature accumulates around cells to mediate surface phenomena. Its principal ecological role lies in initial attachment and development of sessile communities. By providing bridging polymers rich in hydroxyl and carboxyl
Ref: Costerton et al., Ann Rev Microbiol 1995, Biofilms; Alberts et al., Molecular Biology Cell, Chapter 24: Biofilms.
