Production of Chitin and Chitosan

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. 

Conversion of chitin into chitosan involves the deacetylation process, which is a harsh treatment usually performed with concentrated sodium hydroxide solution. Chitin flakes are treated in suspension with aqueous 40-50% caustic solution at 80-120°C with constant stirring for 4-6 h and this treatment is repeated once or more than once for obtaining high-amino-content product. To avoid depolymerization due to oxidation, sodium borohydrate is added. Excess alkali is drained off and the mixture is washed with water several times until it is free from alkali. Most of the alkali is then used either in deproteinization or in deacetylation. Excess water is removed in screw press and the wet chitosan cake is either sun dries or in drier at 60°C. Chitosan thus obtained is in the form of flakes and can be pulverized to powder. The flowchart for the manufacture of chitosan from the starting material (crustacean shells) is shown in Fig. 19.5. 

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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... 

Therefore, this article reviews the recent development of the production process of chitin and chitosan from insects, terrestrial crustaceans, and mushrooms. Moreover, the possibility for the large-scale production of chitin and chitosan from these sources are discussed. 

Moreover, Crestini et al. (1996) reported that the yields of chitosan, viz., 120mg/L of fermentation medium under liquid fermentation conditions, and 6.18g/kg of fermentation medium under solid-state fermentation conditions are produced from the mushrotxn, L. edodes. Based on this data, it can be conad-ered that the cultivation of mushroom on solid support, which is the natural growing method of mushroom, might be the best cultivation method for the production of chitin and chitosan from mushrooms. The yield of extracted chitin and chitosan depends on mushroom species, harvesting time, and chitin and chitosan extraction processes and conditions (POchanavanich and Suntomsuk 2002, Yai and Man 2007a). 

Based on the present knowledge on this topic, the mycelium of basidiomycetes can be considered an alternative source for the production of chitin and chitosan that might be useful for some specific practical applications. Mushroom chitosans have a degree of deacetylation of 70%-90% that depends on mushroom species and treatment conditions, and average molecular weight about 1-2 x 10 Da (Crestini et al. 1996, Pochanavanich and Suntomsuk 2002, Yen and Mau 2007a, Mario et al. 2008). 

Several excellent reviews and research papers for the production of chitin and chitosan have appeared in various journals, international symposia, and conferences on chitin and chitosan. Most of the published papers emphasized the production of chitin and chitosan from aquatic crustaceans and from... 

This work was supported by the Contract Development at Project to develop innovative seeds from Japan Scientific Technology Agency. The authors thank Prof. George A. F. Roberts for his valuable discussions on production of chitin and chitosan from insect and mushroom. The authors are also thankful to Dr. Kyaw Nyein Aye for the personal interview on his experience on industrial scale production of chitin and chitosan from shrimp shells. 

Nwe, N. and W. F. Stevens. 2008. Production of chitin and chitosan and their applications in the medical and biological sector. In Recent Research in Biomedical Aspects of Chitin and Chitosan, ed. H. Tamura, pp. 161-176. Research Signpost, Trivandrum, Kerala, India. 

Varlamov, V. P., Nemtsev, S. V., Zueva, O. Y, Khismatullin, M. R., Khismatullin, R. G., and A. I. Albulov. 2002. Production of chitin and chitosan from bees. Paper presented at the 5th Asia Pacific Chitin and Chitosan Symposium, Bangkok, Thailand. 

Blum, S., Horlacher, P., Trius, A., Wagemans, P., Weitkemper, N., and Albiez, W. 2000. Methods for obtaining natural substances by means of extraction and methods for the production of chitin and chitosan. Patent no. WO/2000/024490. 

Gagn, N. 1993. Production of chitin and chitosan from crustacean waste and their use as a food processing aid. 

Stamford, T. C. M., Stamford, T. L. M., Stamford, N. P., Neto, B. B., and G. M. Campos-Takaki. 2007. Growth of Cunninghamella elegans UCP 542 and production of chitin and chitosan using yam hean medium. Electronic Journal of Biotechnology 1 61-68. 

Sini, T. K., Santhosh, S., and P. T. Mathew. 2007. Study on the production of chitin and chitosan from shrimp shell by using Bacillus subtilis fermentation. Carbohydr. Res. 342 2423 29. 

Written by 40 international contributors who arc leading experts in the field of natural biomaterials, this book provides an overview of the sources and production of chitin and chitosan derivatives. It also covers their... 

Fig. 2 Flow chart of the revised process for the production of chitin and chitosan [27]...

Keeping in mind the importance of chitosan, as well as its economic value as an industrial product, we must pay attention to its key physical parameter, i.e., turbidity. Depending on source, a marked difference is observed in aqueous solutions of chitosan and its derivatives in terms of their turbidity [33]. Turbid aqueous solutions of chitosan and chitosan-derived products greatly lose their commercial value. Such chitosan cannot be used as a commercial product and in some cases may have to be discarded. Therefore, the selection of source plays a pivotal role in the production of chitin and chitosan. Shepherd et al. [20] reported the production of chitosan from New Zealand Arrow squid Notodarus sloani) pens as well as the evaluation of the functional properties of this squid chitosan compared with chitosan extracted from crustacean sources. Squid pen chitin and chitosan were visibly cleaner than chitin and chitosan obtained from crab and crayfish. In addition, due to the lower mineral content of squid pen as compared to cmstacean shells, the demineralization process can be skipped to extract chitin, which also makes the production cheaper. As shown in Table 4, the squid pen chitosan is similar in... 

Toan NV (2009) Production of chitin and chitosan frtnn partially autolyzed shrimp shell. Open Biomater J 1 21-24... 

Stevens WF (2001) Production of chitin and chitosan refinement and sustainability of chemical and biological processing. In Uragami et al (eds) Chitin and chitosan chitin and chitosan in life science. Kodansha Scientific, Tokyo, pp 293-300... 

Joensen O, Villadsen A (1994) Ecological sustainable production of chitin and chitosan. In Kamicki ZS, Brzeski MM, Bykowski PJ, Wojtasz-Pajak A (eds) Chitin world. Wirtschaftsverlag, Bremerhaven, pp 38 7... 

A. Gopalakannan, J.G. India, S.A. Shanmugam, G. Sugumar, Application of proteolytic enzyme, papain for the production of chitin and chitosan from shrimp waste, J. Mar. Biol. Assoc. Ind., 42,167-172,2000. 

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