Uses of Chitin and Chitosan

Various patents have been issued which describe uses for chitin and its derivatives, but, despite the advantages claimed for these materials, they have been little used by industry because of the difficulties encountered in obtaining the raw material. 

Footnote and reference numbers are given in parentheses fw pages on which an author s work is cited by this number only, without motion of his name. Numbers in italic type indicate the pages on which refer-ences for the tables starting on p. 160 are listed. 

Acetate, condensation of, 236 Acetic acid, (ethylenedinitrilo)tetra-, 256 

Adenine, 9-(a-D-ribofuranosyl)-, 115 Adenosine, 115 5-phosphate, 204 5-pyrophosphate, 204 5-triphosphoric acid, 204, 231 —, 2-deoxy-, 228, 229 5-triphosphste, 231 —, iV -hydroxy-, 5-phosphate, 232 Adenylyl peptides, 204 Aerobacter aerogenes, 314, 315 Agrobacterium tumefaciens, 327 Alanine, (3,4-dihydroxyphenyl)-, 269 —, phenyl-, 236, 237, 264, 265, 268 Alditols, acid dissociation constants of, 32, 

Aldonic acids, mechanism of formation of, from aldoses, 51 Aldoses, oxidation of, 50 pKo values of, 32 /3-D-, rates of oxidation of, 50 

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Muzzarelli RA et al (1999) Biochemistry, histology and clinical uses of chitins and chitosans in wound healing. EXS 87 251-264... 

Chitin is also used as excipient and drug carrier under film, gel or powder forms for applications involving mucoadhesivity [84], A recent review describes the use of chitin and chitosan as biomaterials in different biomedical applications [85], Different applications of chitin and that of few chitin derivatives are described in a recent book devoted to chitosan [86]. 

Kumar M. A review of chitin and chitosan applications. React Funct Polym 2000 46( 1) 1. Miyazaki S, Ishii K, Nadai T. The use of chitin and chitosan as drug carriers. Chem Phaim Bull 1981 29(10) 3067. 

Muzzarelh, R. A. A., Mattioh-Belmonte, M., Pugnaloni, A., and Biagini, G. 1999. Biochemistry, histology and clinical uses of chitins and chitosans in wound heahng. In Chitin and Chitinases, eds. P. Jolles and R. A. A. Muzzarelh, pp. 285-293. Basel, Switzerland Birkhauser Verlag. 

Nowadays the food-processing industry is confronted with new statutory requirements to assure the safety of the consumers. In the beverage industry, the use of chitin and chitosan from fungal origin seems to be an alternative of choice as they are natural, biocompatible, and nonaUergen. 

Hirano S, Hirochi K, Hayashi K, Mikami T, Tachibana H. Cosmetic and pharmaceutical uses of chitin and chitosan. In Gebelein CG, Cheng TC, Yang VC, eds. Cosmetic and Pharmaceutical Apphcations of Polymers. New York Plenum Press, 1991 95-104. Ananthapadmanabhan KP. Surfactant solutions adsorption and aggregation properties. In Goddard ED, Ananthapadmanabhan KP, eds. Interactions of Surfactants with Polymers and Proteins. Boca Rat. FL CRC Press, 1993 5-58. 

A worldwide industry has developed aroimd the production and uses of chitin and chitosan. Shrimp and crab shell wastes pose local waste disposal problems... 

Cosmetic uses of chitin and chitosan, and derivatives are comparatively new, but are growing in importance. These include the use of chitin derivatives in various hair and skin care formulations. Chitin derivatives also are being used for artificial skin replacements (wound dressings).15,16... 

The interdependence of methyl jasmonate with chitin- and chitosan-derived elicitors was studied using plant cell suspension cultures of Taxus canadensis. Induction of the biosynthesis of paditaxel and other taxanes was enhanced when methyl jasmonate and elicitors were added 8 days after culture transfer compared to treatments in which only methyl jasmonate or only elicitor was added. The optimal elicitor concentration using AT-acetylchitohexaose was 0.450 pM, but only in the presence of methyl jasmonate. Little, if any, induction of taxane formation occurred with the oligosaccharide alone. The optimal methyl jasmonate concentration was 200 pM using colloidal chitin or oligosaccharides of chitin and chitosan as elicitors. 

Enzymatic hydrolysis is a useful method for the preparation of monomers from chitin and chitosan because the yield of monomers is greater by enzymatic hydrolysis than by acid hydrolysis. The enzyme chitin deacetylase hydrolyzes the acetamido group in the N-acetylglucosamine units of chitin and chitosan, thus generating glucosamine imits and acetic acid (Fig. 2.5). 

In the area of renewable materials, bulk oxypropylation of chitin and chitosan has been performed. Chitin and chitosan are abundant natural polymers obtained from shellfish, such as crab shell or shrimp shell. This solvent free reaction yields viscous polyols. Unfortunately, propylene oxide homopolymer is formed as a by-product but is easily separated. It should be noted that care was taken to minimize the risk involved in the use of toxic, flammable propylene oxide (the reagent in this process). 

Circular dichroism and viscometric methods have been used successfully to determine the degree of acetylation and the MW of chitin and chitosan, respectively (Zhang and Neau, 2001). The DD has no effect on the acidbinding properties of chitosan (Scheruhn et al., 1999). Chitosans have a relatively high DD and strongly enhance fibroblast proliferation, whereas chitosans with lower levels of deacetylation show less activity. The MW and polymer chain length were of little importance (Howling et al., 2001). 

New applications of chitin and its oligomers led to more than 50 patents in the 1930s and the early 1940s. However, commercialization of these products was hindered by inadequate manufacturing services and competition from synthetic polymers (Averbach, 1981). However, after the 1970s, industrial use of chitin and its oligomers increased (Kaye, 1985). Furthermore, improvement in research and small-scale production of chitin and chitosan... 

An interesting application of derivative sp>ectrophotometiy was described by Wu and Zivanovic [46], They proposed the use of the first derivative spectra for determination of the degree of acetylation of chitin and chitosan. They employed the evaluated procedure for commercial samples. 

Chitin, the precursor of chitosan, is a nitrogen containing polysaccharide and is second most abundant biopolymer after cellulose. It is widely distributed in the shells of crustaceans such as crabs, shrimps, lobsters, prawns, squilla, etc., as well as in the exoskeleton of marine zoo-plankton, including coral, jellyfish, and squid pens. About 20-40% chitin is present the exoskeleton of these animals. It is also present in smaller quantities in insects such as butter flies ladybugs, and the cell walls of yeast, mushrooms, and other fungi [Fig. 19.4]. However, since the crustacean shells [crabs, shrimps, lobsters, etc.] are waste products of food industry, these are commercially employed for the production of chitin and chitosan [1, 4, 18], It is believed that at least 10 gigaton of chitin is synthesized and degraded and it is also estimated that over 150,000 tons of chitin is available for commercial use annually. 

It is necessary to prepare several tests, grouped in preliminary, conhrmatory and other tests, for characterization of chitin and chitosan used for manufacturing of medical devices [80]. European Pharmacopoeia as well as requirements of ISO... 

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