Chitin was originally discovered as a component of mushrooms, and potential commercial sources are the mycelia and spores of fungi such as Chytridiomycetes, Bacillus, and Ascomycetes. The mycelia of some Penicillium species may contain up to 20% chitin. Aspergillus niger is also an important source of chitin.
Chitin is sometimes similar to collagen in chordates. It forms the tough, fibrous exoskeletons of insects, crustaceans, and other arthropods,1 and is present in at least one species of algae in addition to being present in some fungi. 2,3 It is estimated that the biosphere synthesizes more than 100 billion tons of chitin per year.
However, current sources of chitin are the shells or skeletal walls of invertebrates, especially shrimp, crabs and lobsters. The name chitin is derived from the Greek word meaning coat or envelope. Chitin is the most abundant organic component of arthropod, annelid, and mollusc skeletal material, providing skeletal support and body armor.
what is chitin
Modern freezing and canning operations of lobster, crab and shrimp result in the generation of large amounts of crustacean waste. These wastes mainly consist of shells and heads, which can be processed into chitin. The US processed about 200,000 tonnes of shrimp, 35,000 tonnes of lobster and 90,000 tonnes of crab. Some of the catch is shipped live, others are partially cleaned at sea, but most are processed in land-based facilities. Other abundant sources of shells are available in processing centers in many parts of the world.
The current world chitin market is estimated at 1,000 to 2,000 tons. Japan is by far the largest user, with production estimated at 1.5 million pounds (6.8 × 105 kg) per year. Europe probably used 500,000 pounds, while the United States seems to use about 150,000 to 200,000 pounds (70–90 103 kg), but this estimate may be too high. Chitin was quoted in the range of $3.50 to $4.50 per pound, and chitosan was quoted in the range of $6.50 to $100 per pound.
The hard shells of crustaceans contain 15-20% chitin and up to 75% calcium carbonate, as well as skeletal proteins. Soft-shelled crustaceans such as shrimp contain 15-30% chitin and 13-40% calcium carbonate, as well as skeletal protein. The calcium carbonate content in lobster shells is lower than that of hard shell crabs, but higher than that of shrimp shells.
Chitin is found in the exoskeleton of most insects, and can be as high as 60% in specific parts, such as flexible parts. The average content of chitin in the cuticle of many different species has been reported to be 33%. The stratum corneum consists of alternating layers of protein and chitin, impregnated with calcium carbonate and pigments, interspersed with polyphenols.
