Production of oligosaccharides

In summary, different strategies for the combinatorial biosynthesis of oHgosaccharides have been established successfully. However, some systems are Hmited mostly to bacterial glycosyltransferases because of their better expression in E. coli. The yeast systems seem to be better suited for expression of mammahan glycosyltransferases however, it remains to be demonstrated if they can be also utilized as living factories for the production of oligosaccharides. 

Table 5.3 Production of oligosaccharides by metabolic engineered living E. coli cells (see Scheme 5.9 for product formulas).

Figure 2.17 Production of oligosaccharides during the hydrolysis of lactose by /5-galactosidase . lactose , monosaccharides O, glucose , oligosaccharides , galactose (modified from Mahoney, 1997).

Endo T, Koizumi S (2000) Large-scale production of oligosaccharides using engineered bacteria. Curr Opin Struct Biol 10 536—541... 

Taniguchi, H. 2005. Carbohydrate active-enzymes for the production of oligosaccharides. In Hou, Ching T. (Ed.), Flandbook of Industrial Biocatalysis (ch 20). London Taylor Francis. 

Takahashi, R., Mizumoto, K., Tajika, K., and Takano, R., Production of oligosaccharides from hemicellulose of woody biomass by enzymatic-hydrolysis. 1. A simple method for isolating beta-D-mannanase-producing microorganisms. Mokuzai Gakkaishi 1992, 38 (12), 1126-1135. 

This approach should notably favor the production of oligo- and polysaccharides, which is highly complex due to the requirements of regio- and stereoselectivity. Enzymes are the tools that are best suited to meet these requirements. A considerable number of industrial processes have been established for the production of oligosaccharides. They are, however, limited to few naturally occurring substrates and enzymes. That means that only products based on... 

Scheme 28 The production of oligosaccharides Gbs, Gb4, LNT-2, LNnT, and LSTd through successive reactions using recombinant bacterial glycosyltransferases.

Enzyme-catalyzed hydrolysis of polysaccharides containing uronic acids is well established, but, during the past few years, it has become evident that bacterial enzymes may degrade such materials by a process involving eliminations and the production of oligosaccharides containing nonreducing, terminal, 4,5-unsaturated, uronic acid residues. 

The identification of oligosaccharide products, which relies on chemical methods such as periodate and lead tetraacetate oxidation, partial acid hydrolysis before and after reduction, electrophoretic mobility in borate and molybdate buffers and chromatography, has been described by Bouveng and Lindberg (29). The alkaline degradation products of oligosaccharides are characteristic of the linkage present and a TLC technique for their separation and detection has recently been described (16). 

Using the way of 80% alcohol extraction and Sevage method could remove lipid-soluble and protein fraction in cells, to ensure isolated oligosacchides be the hydrolysate of semicellulose in primary cell walls of cultured cells from Panax genseng. During the course of acid hydrolysation, the factors influenced must be controlled strictly. The quantity of products of oligosaccharide could be affected on the condition of more high or too low of temperature. 

We have used two types of enzymes for the production of oligosaccharides glycosidases (E.C. sub-class 3.2) and glycosyltransferases (E.C. sub-class 2.4) (9, 10). In this chapter we discuss the relative advantages and disadvantages of using each class of enzyme as a catalyst for the synthesis of complex carbohydrates. 

Scheme 3. Large-scale production of oligosaccharides through coupling of...

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