Sources, Biosynthesis, Properties, Structures and Applications of Halophilic Exopolysaccharides

Saline and hypersaline environments such as natural saline seas, lakes, coastal lagoons, marine salterns, deserts, saline soils, etc. are considered extreme habitats for microbial life. They harbor halophiles as well as halotolerant microorganisms growing in the absence of salt and in the same time tolerant to relatively high salt concentrations. Halophilic microorganisms suggest many advantages for biotechnological exploration like relatively short time course of fermentations, lack of pathogenicity and the production of stable biomolecules, such as exopolysaccharides (EPS), under the extreme conditions of the most industrial processes. The aim of this chapter is to present a summary of the status of the research about the structures and the biosynthesis of exopolysaccharides by halophilic microorganisms, including medium-released and biofilm embedded polysaccharides. Moreover, relationships between the structure and the function of the exopolysaccharides and their possible biotechnological and industrial applications, are discussed.