Exopolysaccharide productions from extremophiles: The chemical structures and their bioactivities

This chapter will discuss some remarkable examples of extremophilic bacteria, isolated from different ecosystems, which produce exopolysaccharides (EPSs). The chapter will also cover the properties of EPSs produced by extremophiles and their possible commercial applications ranging from pharmaceutical to food processing, detoxification and bioremediation. This chapter will also cover the techniques that are used to purify, analyse and structurally characterise the bacterial EPSs; the state of the art in the field of bacterial EPSs research, with mention to the main examples of well-studied and commercially exploited EPSs; an overview of the main EPSs' producing extremophiles that have been isolated from both aquatic and terrestrial environments; the description of the main biosynthetic routes leading to the EPSs production in archaeal and bacterial extremophiles, with reference to the enzymes involved and to the genetic manipulations for biosynthesis's tailoring; the analysis of the most interesting biological properties of extremophiles' EPSs (that can act as anti-inflammatory, immunomodulating and antiviral agents) and of their biotechnological applications in drug delivery systems; and the compendium of the most used techniques to perform the purification, the analysis of chemical composition, the identification of glycoside linkage position and substitution pattern, the determination of the molecular-weight distribution and the structural analysis of EPSs.