Extremophiles: A Versatile Source of Exopolysaccharide

Exopolysaccharides (EPSs) of microbial origin are ubiquitous in nature, have unique properties and can be isolated overall from many bacteria living in extreme conditions either from fresh water, marine environments and soil ecosystems. EPSs make up a substantial component of the extracellular matrix surrounding most microbial cells living in extreme environments such as Arctic and Antarctic ecosystems, saline lakes, geothermal springs, or deep-sea hydrothermal vents. Extremophiles have developed various adaptations, enabling them to compensate for the deleterious effects of such extreme conditions as high temperatures, salt, low pH, or high radiation levels. These biopolymers represent an ecological strategy to resist the extreme conditions: due to their protective nature, EPSs, surrounding the cells, represent a defence mechanism against extreme values of temperature and salinity and they are essential in retention of nutrients of water. Without any doubt, EPSs are rapidly emerging as new and industrially important biomaterials, essentially thanks to their unique and complex chemical structures and properties, with commercial applications in various fields, from agriculture to medicine, microbial enhanced oil recovery and wastewater treatment, passing through the food and pharmaceutical fields, as well as packaging, textile and cosmetics use. Moreover, their high degree of biocompatibility, biodegradability and both environmental and human compatibility, make them viable alternatives to petroleum-based polymers. Recent studies on polysaccharide produced extremophiles, isolated from hypersaline environments, deep-sea hydrothermal vents, and volcanic and hydrothermal areas, will be reported including chemical structures, fermentation technology, biotechnological and biomedical applications.