Microbial exopolysaccharides: Resources and bioactive properties

Polysaccharides are present in all life forms and display multifarious biochemical structures. They are important natural products, present in microorganisms, animals and plants and exhibit various biological functions. Microbial exopolysaccharides (EPSs) are synthesized by both eukaryotes and prokaryotes and they mostly provide cell adhesion and protection against negative environmental conditions. In comparison to other natural sources, microbial EPSs usually have considerably shorter production times and their extraction is quite simple. These polysaccharides present a wide variety of structures and physicochemical properties, allowing the possibility to apply them in areas ranging from use as rheology modifiers of food systems to therapeutic agents. Microbial EPSs have various applications in cosmetic, food, and textile industries and they have been used widely in diverse fields of the food industry to enhance the quality of the product. Moreover, they have an important role in health through antimicrobial, antioxidant, anticancer, and cholesterol-lowering effects, antiviral activities and prebiotic properties. This review focuses on bioactive characteristics, applications and resources of exopolysaccharides produced by microorganisms.