Pseudomonas aeruginosa biofilm exopolysaccharides: assembly, function, and degradation

The biofilm matrix is a fortress; sheltering bacteria in a protective and nourishing barrier that allows for growth and adaptation to various surroundings. A variety of different components are found within the matrix including water, lipids, proteins, extracellular DNA, RNA, membrane vesicles, phages, and exopolysaccharides. As part of its biofilm matrix, Pseudomonas aeruginosa is genetically capable of producing three chemically distinct exopolysaccharides - alginate, Pel, and Psl - each of which has a distinct role in biofilm formation and immune evasion during infection. The polymers are produced by highly conserved mechanisms of secretion, involving many proteins that span both the inner and outer bacterial membranes. Experimentally determined structures, predictive modelling of proteins whose structures are yet to be solved, and structural homology comparisons give us insight into the molecular mechanisms of these secretion systems, from polymer synthesis to modification and export. Here, we review recent advances that enhance our understanding of P. aeruginosa multiprotein exopolysaccharide biosynthetic complexes, and how the glycoside hydrolases/lyases within these systems have been commandeered for antimicrobial applications. This comprehensive review highlights recent advances in the field of Pseudomonas aeruginosa biofilm exopolysaccharide biosynthesis and discusses the potential use of glycoside hydrolases for antibiofilm therapies.

Automated summary

The biofilm matrix provides a protective and nourishing barrier for bacteria, and consists of various components. Pseudomonas aeruginosa is genetically capable of producing three chemically distinct exopolysaccharides, each playing a different role in biofilm formation and immune evasion. Recent advances have enhanced our understanding of the molecular mechanisms behind these secretion systems and the potential use of enzymes in antimicrobial applications.