Exopolymers
Synonyms
Keywords
Biofilm, cells, cyanobacteria, polymers
Definition
Exopolymers are polymers that are deposited outside the (microbial) cell. These polymers are predominantly composed of carbohydrates, but many contain various other components such as proteins, DNA, and glycolipids. Some exopolymers consist of neutral sugars such as glucose, while others are acidic in nature and contain a variety of charged groups such as the uronic acids, carboxy groups, sulfated sugars, or pyruvate groups. The molecular structure and composition of exopolymers is therefore highly diverse and complex. Exopolymers form the matrix of biofilms in which the microorganisms are embedded, but also serve a plethora of other functions.
Overview
Exopolymers are by definition polymers that are deposited outside the cell wall. These include sheaths or investments in which the cell, but often also aggregates or...
References and Further Reading
- Braissant O, Decho AW, Przekop KM, Gallagher KL, Glunk C, Dupraz C, Visscher PT (2009) Characteristics and turnover of exopolymeric substances in a hypersaline microbial mat. FEMS Microbiol Ecol 67:293–307CrossRefGoogle Scholar
- Branda SS, Vik Å, Friedman L, Kolter R (2005) Biofilms: the matrix revisited. Trends Microbiol 13:20–26CrossRefGoogle Scholar
- Decho AW (1990) Microbial exopolymer secretions in ocean environments: their role(s) in food webs and marine processes. Oceanogr Mar Biol 28:73–153Google Scholar
- Hoagland KD, Rosowski JR, Gretz MR, Roemer SC (1993) Diatom extracellular polymeric substances – function, fine structure, chemistry, and physiology. J Phycol 29:537–566CrossRefGoogle Scholar
- Hoiczyk E, Hansel A (2000) Cyanobacterial cell walls: news from an unusual prokaryotic envelope. J Bacteriol 182:1191–1199CrossRefGoogle Scholar
- Pereira S, Zille A, Micheletti E, Moradas-Ferreira P, De Philippis R, Tamagnini P (2009) Complexity of cyanobacterial exopolysaccharides: composition, structures, inducing factors and putative genes involved in their biosynthesis and assembly. FEMS Microbiol Rev 33:917–941CrossRefGoogle Scholar
- Stal LJ (2003) Microphytobenthos, their extracellular polymeric substances, and the morphogenesis of intertidal sediments. Geomicrobiol J 20:463–478CrossRefGoogle Scholar
- Sutherland IW (2001) Biofilm exopolysaccharides: a strong and sticky framework. Microbiology 147:3–9Google Scholar