Polysaccharides. Группа авторов

Polysaccharides - Группа авторов


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      Marine Polysaccharides: Properties and Applications

       Tonmoy Ghosh, Rabinder Singh, Asha Arumugam Nesamma and Pannaga Pavan Jutur*

       Omics of Algae Group and DBT-ICGEB Centre for Advanced Bioenergy Research, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India

       Abstract

      Polysaccharides arguably are the most diverse group of biopolymers on earth with critical roles in energy storage, cellular structure components and safekeeping of hereditary information. With the wide variety of structures, source organisms and years of evolutionary history in different habitats, these biomolecules encompass an array of derivatizations and conjugation with other biomolecules. This chapter would mainly focus on the major polysaccharides obtained from the marine environment, i.e. crustaceans, seaweeds, and microalgae. The polysaccharides will be discussed in context of their various properties and the applications for which they are or can be exploited in industries such as biomedical, pharmaceutical, agriculture, and food. This chapter summarizes the diversity of polysaccharides with the underlying basic principles and their versatile applications.

      Keywords: Alginate, cellulose, chitosan, crustaceans, marine polysaccharides, seaweed

      Polysaccharides are high-molecular polymers, also called glycans, made up of repeated units of monosaccharides and bound to unique glycoside bonds. They are omnipresent in the biological world, with roles as diverse as energy storage, building the cellular framework, to encoding genetic information through generations [6]. They can be water soluble or insoluble, and their structural diversity stems from different derivatization reactions taking place. On the basis of monomeric units, they can be divided in to 2 categories: homopolysaccharide (composed of same monomers), and heteropolysaccharide (composed of 2 or more different monomers). However, due to the diversity of the polysaccharide family, a more general classification is based on the intended functions:

       Storage polysaccharides (glycogen, starch)

       Structural polysaccharides (chitin, cellulose)

       Hereditary (DNA, RNA); conjugated with nitrogenous bases.

      Structurally, polysaccharides can be linear (cellulose, agar) or branched (amylopectins, arabinans) [7]. Marine polysaccharides are essentially derived from marine organisms, like algae, seaweeds, bacteria, corals, sponges, fungi, and crustaceans (organisms like shrimps, crabs, prawns, and lobsters). This chapter addresses the properties and major applications of polysaccharides from marine sources in biomedical, food, pharmaceutical and agrarian industries.

      Polysaccharides, being essential to all life forms, are found in a variety of organisms in different forms. Marine polysaccharides are mainly derived from crustaceans (shrimps, crabs), seaweeds, bacteria, and fungi. Table 3.1 lists the major polysaccharides along with the sources, monomers and type of linkages. In addition, the following sections will address these molecules in more detail.

      Polysaccharides are found in almost all living organisms, residing typically in a wide variety of habitats. The heterogeneity of polysaccharides and alternative methods of derivatization across time has given rise to several candidates with a broad spectrum of physicochemical properties. In this chapter of marine polysaccharides, we will concentrate on a few of candidate biopolymers.

      3.3.1 Cellulose

      Table 3.1 Types, sources, monomers, and linkages found in common polysaccharides.

Type Sources Monomers Linkage References
Cellulose Seaweed, bacteria Glucose β(1→4) [8, 10]
Chitosan Shrimps, crabs, fungi N-acetyl glucosamine, glucosamine β(1→4) [13]
Alginate Seaweed β-D-mannuronate, α-L-guluronate β(1→4) [208]
Carrageenan Seaweed Galactose, 3,6-anhydrogalactose, ester bound sulfate [208]
Agar Seaweed 3,6-anhydro-α-lgalactopyranose, β-dgalactopyranose [208]
Porphyran Seaweed β-D-galactose, α-Lgalactose, 3,6-anhydro- α-L-galactose [40]
Fucoidan Seaweed
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