CHITIN & CHITOSAN (TECHNICAL & MEDICAL GRADE)

Chitin is a white, hard, inelastic, nitrogenous, polysaccharide found in the outer skeleton of insects, crabs, shrimps and lobsters and in the internal structures of invertebrates. It is the second most abundant organic compound next to cellulose. It is a macro molecular linear polymer of_ (1-4) N acetyl D glucosamine and is insoluble in water and many organic solvents. Chitin itself has only a few applications; it acts more as a precursor of Chitosan, its most familiar derivative.

Chitosan is deacetylated chitin, and is polymer of _(1-4) acetyl – D glucosamine. It has multifarious uses in the cosmetic, pharmaceutical and medical industries. It is even considered as a wonder drug of the twenty-first century due to its versatile utility.

Chitin is a chemical compound belong to glucosamine polysaccharide group categories. It contains about 7% nitrogen, and is structurally similar to cellulose.

It is the principal constituent of the shells of prawn fish, shrimps, crabs, lobsters, beetles and other sea fishes. It is also found in some fungi, algal, and yeasts.

Fish is a valuable and easily accessible source of food, rich in proteins. India has abundant marine and inland fish resources. It has a coast-line c. 4,667 km. long and a continental shelf 2,59,000 sq. km. or more in area, offering considerable scope for the establishment of fisheries. The Bay of Bengal and the Arabian Sea abound in fishing grounds; gulfs and bays all along the coast and a large number of islands with their mangrove swamps and coral reefs, are rich sources of marine fish.

Tidal estuarine waters in the mouths of large and perennial rivers, large brackish water lakes, backwaters, lagoons and swamps scattered along the entire coast-line, afford lucrative estuarine fisheries. Vast stretches of fresh water consisting of rivers, streams, lakes, reservoirs, tanks, ponds and paddy fields offer scope for inland fisheries. The principal rivers of India, including their main tributaries, have a total length of c. 27,360 km. and the length of canals and irrigation channels is c. 1,12,650 km. When added to other freshwater resources, the total surface would run to several million acres of which not more than a million acres are under fish culture. Most of these freshwater resources, though culturable, are at present lying fallow.

In order to study the distribution and bionomics of marine fishes inhabiting Indian waters and to assess the topographic conditions for the establishment of fisheries, the Indian coast has been divided into the following 12 bio-geographical zones:

Zone 1: West Bengal and Orissa
Zone 2: Andhra coast (south of Gopalpur to north of Visakhapatnam)
Zone 3: Andhra coast (Visakhapatanam to Masulipatham)
Zone 4: Andhra coast (south of Masulipatnam to north of Pulicat lake)
Zone 5: Coromandel coast (Pulicat lake to Cuddalore)
Zone 6: Coromandel coast (south of Cuddalore to Devipatnam)
Zone 7: Palk Bay and Gulf of Manaar (south of Devipatnam to north of Cape Comorin)

Zone 8: Kerala and South Malabar (Cape Comorin to Ponnani River)
Zone 9: Malabar and South Kanara (north of Ponnani River to Mangalore)
Zone 10: Konkan coast (north of Mangalore to south of Ratnagiri)
Zone 11: Mumbai and Gujarat coast (Ratnagiri to Broach)
Zone 12: Kathiawar coast

Fishing in Indian seas is generally contained to a narrow coastal belt, 11-16 km. in width and the richer offshore and deep sea waters are practically unexploited. This is largely due to the inadequacy of fishing craft and gear in use. Over 49% of the total fish landings are sun-dried, salted or pickled for future consumption, but the curing processes are by and large unscientific and the product is inferior. A good part of the landings in different parts of the country gets spoiled owing to lack of adequate transport and preservation facilities and is used as manure or otherwise disposed.

Chitin is a polysaccharide that is widely spread among marine and terrestrial invertebrates and lower forms of the plant Kingdom. Chitin is a promizing natural raw material for industrial use. It is biodegradable and non-toxic. Its biological production is about 2,00,000 tons/Annum all over the World.

Chitosan is a deacetylated derivative of chitin. It is polysaccharide found in nature with an amino group, contained in the shells of Crustacea such as crab, shrimp etc. Chitosan is a white to light red solid powder, insoluble in water, soluble in organic acid, but indigestible by human digestive enzymes. Therefore, it is used as one of the so called dietary fibers.

Chitin is one of the three most abundant polysaccharides in nature, in addition to cellulose and starch. It ranks second to cellulose as the most plentiful organic compound on earth. Chitin and its derivatives have many properties that make them attractive for a wide variety of applications, from food, nutrition and cosmetics to biomedicine, agriculture and the environment.

Their antibacterial, anti-fungal and anti viral properties make them particularly useful for biomedical applications, such as wound dressings, surgical sufures and as aids in cataract surgery and periodontal disease treatment.

Chitin/Chitosan is the most important additive and product from marine bio sources beside Calcium, Astaxanthin, Glucosamine. The middle extraction value of chitosan is 5%. It is strongly depend on process and knowhow which kind of extraction grade the production will reach.

Chitosan/ka?t?sæn/is a linear polysaccharide composed of randomly distributed ß-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It is made by treating shrimp and other crustacean shells with the alkali sodium hydroxide.

Chitosan has a number of commercial and possible biomedical uses. It can be used in agriculture as a seed treatment and biopesticide, helping plants to fight off fungal infections. In winemaking it can be used as a fining agent, also helping to prevent spoilage. In industry, it can be used in a self-healing polyurethane paint coating. In medicine, it may be useful in bandages to reduce bleeding and as an antibacterial agent; it can also be used to help deliver drugs through the skin.

More controversially, chitosan has been asserted to have use in limiting fat absorption, which would make it useful for dieting, but there is evidence against this.

Other uses of chitosan that have been researched include use as a soluble dietary fiber.

Chitosan is produced commercially by deacetylation of chitin, which is the structural element in the exoskeleton of crustaceans (such as crabs and shrimp) and cell walls of fungi. The degree of deacetylation (%DD) can be determined by NMR spectroscopy, and the %DD in commercial chitosans ranges from 60 to 100%. On average, the molecular weight of commercially produced chitosan is between 3800 and 20,000 Daltons. A common method for the synthesis of chitosan is the deacetylation of chitin using sodium hydroxide in excess as a reagent and water as a solvent. This reaction pathway, when allowed to go to completion (complete deacetylation) yields up to 98% product.

The amino group in chitosan has a pKa value of ~6.5, which leads to a protonation in acidic to neutral solution with a charge density dependent on pH and the %DA-value. This makes chitosan water-soluble and a bioadhesive which readily binds to negatively charged surfaces such as mucosal membranes. Chitosan enhances the transport of polar drugs across epithelial surfaces, and is biocompatible and biodegradable. It is not approved by FDA for drug delivery though. Purified quantities of chitosans are available for biomedical applications.

Chitosan and its derivatives, such as trimethylchitosan (where the amino group has been trimethylated), have been used in nonviral gene delivery. Trimethylchitosan, or quaternised chitosan, has been shown to transfect breast cancer cells, with increased degree of trimethylation increasing the cytotoxicity; at approximately 50% trimethylation, the derivative is the most efficient at gene delivery. Oligomeric derivatives (3-6 kDa) are relatively nontoxic and have good gene delivery properties.