Enzymatic Polymerizations of Polysaccharides

Oligo- and polysaccharides are important macromolecules in living systems, showing their multifunctional characteristics in the construction of cell walls, energy storage, cell recognition and their immune response. 

Polysaccharides are an abundant source of raw materials that are interesting due to the biodegradable, biocompatible and renewable character. Saccharides are expected to play an increasingly bigger role as raw material in the future and to replace petrol-based materials. Already, polysaccharides find their way into many disparate fields of industry a short overview is given in Table 9.1. 

Conventional chemical synthetic approaches are, in many cases, inadequate to provide substantial quantities of saccharides. The difficulties arise from realizing complete regio- and stereo-control of the glycosylating process. At present, no such methods are available because, in chemical synthesis, most of the difficulties arise from the laborious regio- and stereochemical control. Most synthetic approaches are therefore based on the modification or degradation of naturally occurring polysaccharides resulting in less than perfect products. 

Saccharide synthesis in vivo is a very complex process that is not regulated by universally conserved codes, and has not been automated in vitro yet. Ultimately, in order to provide useful quantities of materials a combination of chemical and enzymatic techniques is necessary. 

1) In memoriam Beate Pfannemiiller her work inspired much of the research reviewed in this chapter. 

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Enzymatic Polymerizations of Polysaccharides Table 9.1 Polysaccharide processing industries. 

Some excellent reviews have appeared extensively covering the enzymatic polymerization of polysaccharides using glycoside hydrolases [233-245]. Two examples of this field are highlighted below for more details please refer to these reviews. 

Abstract Transferases are enzymes that catalyze reactions in which a group is transferred from one compound to another. This makes these enzymes ideal catalysts for polymerization reactions. In nature, transferases are responsible for the synthesis of many important natural macromolecules. In synthetic polymer chemistry, various transferases are used to synthesize polymers in vitro. This chapter reviews some of these approaches, such as the enzymatic polymerization of polyesters, polysaccharides, and polyisoprene. 

Polysaccharides are among the most important biopolymers as are proteins and nucleic acids in natin-e. They are regarded as three important families of natural biomacromolecules. As to the enzymatic polymerization for polysaccharides, hydrolases and transferases are reported to catalyze their synthetic reactions. 

We reviewed the development of amylose-grafted polymeric materials by the chemoenzymatic method the combination of chemical reaction to link the maltooligosaccharide as a primer to polymer backbones or polymerizable groups with the phosphorylase-catalyzed enzymatic polymerization of G-l-P to produce amylose chain. The present works are based on the viewpoint that polysaccharides can form promising new... 

Enzymes are generally classified into six groups. Table 1 shows typical polymers produced with catalysis by respective enzymes. The target macromolecules for the enzymatic polymerization have been polysaccharides, poly(amino acid)s, polyesters, polycarbonates, phenolic polymers, poly(aniline)s, vinyl polymers, etc. In the standpoint of potential industrial applications, this chapter deals with recent topics on enzymatic synthesis of polyesters and phenolic polymers by using enzymes as catalyst. 

Plants and animals synthesize a number of polymers (e.g., polysaccharides, proteins, nucleic acids) by reactions that almost always require a catalyst. The catalysts present in living systems are usually proteins and are called enzymes. Reactions catalyzed by enzymes are called enzymatic reactions, polymerizations catalyzed by enzymes are enzymatic polymerizations. Humans benefit from naturally occurring polymers in many ways. Our plant and animal foodstuffs consist of these polymers as well as nonpolymeric materials (e.g., sugar, vitamins, minerals). We use the polysaccharide cellulose (wood) to build homes and other structures and to produce paper. 

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