Glossary
The English version of our glossary is currently under construction and will be regularly updated.
Extracellular polymeric substances (EPSs)
EPSs are produced by various species of bacteria and cover the cell as a capsule. The capsule performs a wide range of functions, not all of which are fully understood.
Extracellular polymeric substances (EPSs) can consist of various types of molecule, like polysaccharides, proteins, lipids, nucleic acids and other components. They are actively secreted by cells and cling to their surface as a sticky substance or aggregate to form dense matrix.
EPSs perform a range of functions in the ecosystems where they are found. They contribute e.g. to the cohesion of cells and organisms, and to the formation of structures like biofilms. Biofilms are microbial communities composed of numerous bacteria and other microorganisms, which are held together by EPSs. EPSs can also help to trap and store nutrients and water, which is vital to the survival and growth of microorganisms and plants alike. EPSs can also help to fend off threats, providing a barrier to keep out antimicrobial compounds, predators and parasites.
Further, EPSs are used in environmental biotechnology – as biological adhesives, they can be used to treat wastewater or soils contaminated with heavy metals. Through aggregation and by forming biofilms, EPSs can boost the efficiency of environmental biological processes.