Methods of Chitin Production a Short Review

Such characteristics, diverse applications in
areas such as agriculture, food, environmental, and as two areas
with greater focus: pharmaceutical and health [3,4]. Its structure
consists of N-acetyl-d-glucosamine units with β- (1,4) bonds, having
as main characteristic the insolubility in water and some organic
acids [5]. Chitin belongs to the group of structural polysaccharides,
together with cellulose, the second polymer being more abundant
in the biosphere [6-9]. Due to its structural nature, a product
release system was not found in any of the arthropod exoskeleton,
in the structures of molluscs [10], in the cell wall of fungi [11,12],
protozoa and bacteria, egg shells of nematodes [13,14], the shrimp
fishery residue being the most widely used source [15].Throughout
the decades of research and handling of this polymer, many methods
of extraction have been developed, being the chemical method most
found in the literature, being also used in the means of production
of industrial chitin.
The USA, Japan, India, Canada, China, South Korea, Russia
and Norway generally use the reject of crustacean fishing for
production. The use of strong acids and bases in the chitin
extraction process generates critical points to the process, such as:
high cost of the materials involved, generation of chemical effluent
and final product with low levels of purity [16,17]. Biological
processes become more attractive because they have an affordable
cost of production, do not generate high risk effluent (such as the
chemical process) and high-quality final product [18,19]. All the
processes found in the literature are an objective: to obtain chitin
by separating the proteins and minerals from the raw material used
[20]. Chitin, besides having great biotechnological value, generates
by-products (such as chitosan) that also have added value and even
more relevant properties. In this paper we discuss the already
known processes of obtaining chitin known and registered in the
literature of 2010 up to the present moment: Chemical, enzymatic
and biological processes relating the different methods of obtaining
and with the objective to identify the particularities of each process
regarding the industrial viability and economically balancing them
so that the reader concludes the best process for their research,
also the possibility of executing quality improvements in these
processes.
We will also discuss the polymorphic structures of α- and
β-chitin and the different methods of obtaining each, since different
processes are required in each of them due to their structures,
properties and reactivity. The main objective of this review is to be
able to relate the different processes of obtaining chitin with the
most suitable applications for the method, based on such relation in
aspects such as degree of purity and economic applicability.