Biomedical Application of Carbohydrates from Marine Microbes
Polysaccharides are natural macromolecules composed of osidic monomers and are present in all organisms such as microorganisms, plants, and animals, where they are accessible in the form of glycogen, starch, and cellulose. However, when a polysaccharide contains only one kind of monosaccharide molecule, it is known as a homopolysaccharide, whereas those containing more than one kind of monosaccharide are called heteropolysaccharides. Some monosaccharide derivatives found in polysaccharides include the amino sugars (d-glucosamine and d-galactosamine) as well as their derivatives (N-acetylneuraminic acid and N-acetylmuramic acid), and simple sugar acids (glucuronic and iduronic acids). Polysaccharides have unique characters. Especially, marine microbial polysaccharides synthesized and secreted into the external environment or are synthesized extracellularly by cellwall-anchored enzymes may be referred to as EPSs. The natural biocompatibility and apparent nontoxic nature of some of these microbial exopolysaccharides have prompted their uses in numerous medical applications, such as scaffolds or matrices in tissue engineering, wound dressing, and drug delivery, thus making them further attractive compared to polysaccharides obtained from plants and microalgae (Sutherland, 1998; Otero and Vincenzini, 2003; Rehm, 2010). Some biopolymers get gradually degraded in vivo, making them suitable for use in tissue replacement and controlled drug release (Rehm, 2010). However, the greatest potential of microbial EPSs is their use in pharmaceuticals and biomedicine, wherein traditional polymers fail to comply with the required degree of purity or lack some specic functional properties. Despite the great diversity of molecular structures already described for microbial EPSs, only a few have been industrially developed (Filomena et al., 2011).