ABSTRACT
Polysaccharides of both plant and animal origin display a wide range of biological functions. The diversity of the marine resource, which is closely linked to that of marine ecosystems, represents a vast field of investigation for biotechnology. Research underway for several years on very particular or atypical marine ecosystems has enabled the discovery of new animal and microbial species. Marine macroresources are currently widely exploited to produce hydrocolloids with gelling or thickening properties, such as alginates, agars, and carrageenans. However, the exploitation of macroresources is affected by problems of physical access to certain habitats; seasonal variations; as well as climatic, ecological, or political hazards. Microorganisms, such as fungi, microalgae, cyanobacteria, and bacteria, have many advantages over macroresources: they can be produced under fully controlled culture conditions compatible with current safety standards (traceability, containment). Marine species, especially microorganisms, offer the richest source of polysaccharides. Besides the capsular polysaccharides, the exopolysaccharides found in the extracellular medium are particularly attractive as a new source of high-added-value bioengineered molecules. This chapter discusses the great structural diversity of marine microbial exopolysaccharides and their biological properties in relation to their biochemical compositions for future development in the pharmaceuticals sector.
