Jun Ichi Kadokawa
In this presentation, precision synthesis of polysaccharide based functional polymeric materials by enzymatic approach is reported. The enzymatic approach has been identified as a useful tool to precisely synthesize functional polysaccharides, which have been interestingly much attention as new biomedical and tissue engineering materials. Phosphorylase is one of the enzymes that are practically used as the catalyst for synthesis of polysaccharides with well-defined structure. Phosphorylase catalyzed enzymatic polymerization is progressed by using and ltooligosaccharide as monomer and primer, respectively, to produce amylose. As the polymerization is initiated from the primer, it can be conducted using primers covalently immobilized to other polymeric materials (immobilized primers), giving rise to amylose-grafted polymeric materials. By means of the property of the spontaneously formation of double helix from amyloses, the phosphorylase-catalyzed enzymatic polymerization using the immobilized primers produces network structures composed of the double helix cross-linking points . In most cases, furthermore, the enzymatic polymerization solutions turns into hydrogels. For example, the phosphorylase-catalyzed enzymatic polymerization using maltooligosaccharide-grafted chitin nanofibers produced amylose-grafted chitin nanofiber hydrogels. Moreover, microstructures, which were hierarchically constructed by lyophilization of the hydrogels, were changed from network to porous morphologies depending on the molecular weights of amylose graft chains.
The nearness of elevated levels of NSPs in grain items will decrease the dietary benefit of the grain, a factor that is of essentialness in the creature feed industry. A significant element of NSPs is their capacity to tie water, which permits them to go about as hydrocolloids and lopsidedly impact the rheology of watery frameworks. In preparing, the NSPs of wheat can upgrade water maintenance and surface of bread and cakes. Sanitized NSPs can be utilized as crude materials for the food-added substance industry, which is a significant client of polysaccharide surface modifiers, stabilizers, and gelling specialists. Presently, conventional grains are not significant wellsprings of mechanical polysaccharide hydrocolloids yet appeal on customary supplies makes this a serious territory for improvement. In any case, one of the significant advantages of NSPs is that on utilization they add to the dietary fiber substance of the food.
The NSPs together structure the significant piece of the dietary fiber of grain crops. Dietary fiber is the portion of an expended food which isn't debased in the gut. As human stomach related proteins can just cut α-(1–4) glucan bonds, polysaccharides other than starch are a piece of the dietary fiber. Dietary fiber can be both solvent or insoluble. There are fewer different polymers present in plant tissues, for example, lignin, which likewise structure some portion of the dietary fiber. Notwithstanding, the most straightforward accessible proportion of the amount of NSP in grains is the degree of dietary fiber present ( Table 1 ) and frequently this is the main figure accessible for some, minor grain crops that have not been investigated in detail for polysaccharide arrangement.
Polysaccharides made out of numerous atoms of one sugar or one sugar subordinate are called homopolysaccharides (homoglycans). Homopolysaccharides made out of glucose incorporate glycogen and starch—the capacity sugars of creatures and plants, individually—just as cellulose, the significant basic part of most plants. Arrangements of dextran, a glucose homopolysaccharide found in sludges emitted by specific microorganisms, are utilized alternative for blood plasma in rewarding stun. Different homopolysaccharides incorporate pentosans (made out of arabinose or xylose) from woods, nuts, and other plant items; and fructans (levans) made out of fructose, for example, inulin from roots and tubers of the Jerusalem artichoke and dahlia. Mannose homopolysaccharides happen in ivory nuts, orchid tubers, pine trees, growths, and microscopic organisms. Gelatins, found in products of the soil and utilized monetarily as gelling operators, comprise of a subsidiary of galacturonic corrosive (itself a subordinate of the sugar galactose). The rehashing unit of chitin, a segment of the external skeleton of arthropods is N-acetyl-D-glucosamine, a compound got from glucose; shells of arthropods, for example, crabs and lobsters contain around 20 percent chitin. It is additionally found in specific structures of annelids, mollusks, and other invertebrate gatherings (e.g., jellyfishes, bryozoans, nematodes, and acanthocephalans). The cell dividers of most growths likewise are chitin. Chitin in nature is connected to protein.
Polysaccharides comprising of atoms of more than one sugar or sugar subordinate are called heteropolysaccharides (heteroglycans). Most contain just two distinct units and are related with proteins (glycoproteins—e.g., gamma globulin from blood plasma, corrosive mucopolysaccharides) or lipids (glycolipids—e.g., gangliosides in the focal sensory system). Corrosive mucopolysaccharides are generally conveyed in creature tissues. The essential unit is an alleged blended disaccharide comprising of glucuronic corrosive connected to N-acetyl-D-glucosamine. The most inexhaustible mucopolysaccharide, hyaluronic corrosive from connective tissue, is additionally the significant part of joint liquid (synovia) and happens in the delicate connective tissue (Wharton's jam) of the umbilical rope of warm blooded creatures. Glucuronic corrosive connected to N-acetyl-D-galactosamine is the rehashing unit of chondroitin sulfate, a heteropolysaccharide found in ligament. Heparin, a heteropolysaccharide identified with the corrosive mucopolysaccharides, has anticoagulant properties and is available in connective and different tissues.
Jun Ichi Kadokawa received his PhD Degree in 1992. He then joined Yamagata University as a research associate. From 1996 to 1997, he worked as a Visiting Scientist at the Max-Planck-Institute for Polymer Research in Germany. In 1999, he became an associate professor at Yamagata University and moved to Tohoku University in 2002. He was appointed as a Professor of Kagoshima University in 2004. His research interests focuses on polysaccharide materials. He received the Award for encouragement of research in polymer science (1997) and the cellulose society of Japan award (2009). He has published more than 200 papers in academic journals.