Chitin & Chitosan

Eco-friendly products of our time and renewable resources for processes and biologic  processes used for these resources are attracting more and more attention, Particularly wastes of plant and food products in relation to this process add nutritional value substances to regional ecosystems. The most conventional way for reducing such a load
value is to ideally evaluate such wastes with high nutritional value. Purpose of this study is to obtain chemical substances and their derivatives in different properties by using wastes of shellfish (shrimp, crab, lobster mussels etc.) in chemical and biological processes. Our objectives with this study in long run is to convert renewable resources into different chemical substances and their derivatives used especially in medical medicine having different functions by using chemical/biological methods. The most prominent potential byproduct is chitin production of a biopolymer [polysaccharide). For this reason, primarily chitin production is targeted based on wastes of solid seafood in this project. Gradual rise of chitin and chitin derivatives is caused by their obtainment from byproducts or wastes unlike petroleum derivatives, being a renewable resource, being not toxic and allergic, being anti-microbial and also biodegradable. Chitin, chitosan and its derivatives will respond both wide range of application area and will make this use permanent; implementing new production process will be of great help in regional and national platforms. For this end, in this study, chitosan and connected chitosan and derivatives will be obtained by using seafood wastes and byproducts consumed primarily in Aegean region. It will be attempted to create derivatives having a broader functional property by modifying the chitosan obtained by microbial (enzymatic) and/or chemical methods. A vast majority of chitosan produced in industrial sense is used for removing heavy metals from potable water and contaminated potable water, pesticides and paints. Other areas in which chitosan is widely used in commercial aspect are as follows: Preservative in foodstufl antibacterial agent in textile industry, additives in medical and pharmaceutical applications, antibacterial, anti-cholesterol, additives in cosmetic industry, biotechnological studies and animal nutrition and coagulant. Primary objective of the study is to obtain chitin or chitosan in industrial scale with low cost by evaluating shellfish seafood wastes and in particular, to expand its use in Turkey.

Shellfish solid wastes not treated in water products processing plants pose a vast potential for production of some value-added materials. solid waste in 3.5 million tons values each year are abandoned on an earth surface by processing industry and such volume gradually increased brings forth a problem of disposal of these wastes. (Ktrubagaran, 2005). When processing plants residues are spilled into the sea without being treated, they pose critical predicaments such as pollution, contamination and adversely affect our environmental health. (Qalkr and Krhng, 2004). Treatment of these wastes is of utmost importance in terms of seafood industry and public health.

The following figures are provided for shellfish water products hunted in Turkey according to 2003 data of Statistics Institute of Statistics. Mussel: 8100 tonnes, shrimp:6000 tons, cockle (sand mussel): 79700 tonnes, sea snail: 5500 tons According to the same report , 815 tonnes of mussels have been grown. (statistical Yearbook of Turkey 2004). No data relating to quantity and evaluation of wastes has been present in the report. Although shellfish seafood wastes are not treated in Turkey, various industrial products are obtained from these residues in different countries and these products are utilized in different sectors. Thus, in this study, treatment of such solid residues having particular potential in Turkey constitutes primary objective of the study. Out of these residues are used in the sense of treatment of productions o primarily chitin ( Li-Qunwu et al., 2002; Tsae et al., 2002; Aberg et al., 2004; Beaney et al., 2005) and protein hydrolysate (faswal 1990) and pigment extraction [Chen and Meyers 1983).

Chitin and chitosan to be produced in this study are natural polymer substance available in plenty amount in nature and made up of residues of glucosamine and Nacetylglucosamine with high molecule weight, easily biodegradable and toxic. After cellulose, it is the most abundant polymer in the world.

Chitin production process is conventionally made up of use of acids for demineralization and also bases for deproteinization. However, these processes may cause polymer to be its hydrolysis, undesirable and unexpected physical properties and contamination. (Simpson et al L994) For this reason, biological processes using microorganisms for demineralization and deproteinization have been recommended alternative for these
chemical processes with costly and non-eco friendly nature. (Hall and De Silva 7992; Shirai et al. t997; Rao and Stevens L997; Rao et al., 2000; fung et al 2005). Demineralization of lactic residues have been investigated in the presence of organic acids or various salts of a carbon source in an environment with lactic acid bacteria. (Hall
and De Silva 1992; Shirai et al. 1-998; Rao et al., 2002). Processes wherein result of treatment with microorganism producing protease producing deproteinization operation and also both two processes, namely, deproteinization process have been carried out in the same environment.

flung et al 2005). Through this biological approach, rich liquid fraction in terms of protein, mineral and asthaxanth and chitin fraction as solid are obtained. Liquid portion can be used for human or animal consumption as protein-mineral additive. However, current studies could not go beyond laboratory scale due to being costly and chemical
methods have been used for production of industrial chitin and are still used.

Protein constitutes 30-40 %o of Crustacea shellfish residues, 50 0/o calcium carbonate, 30- 30 o/o chitin. (f ohson and Peniston 1982). Undoubtedly, these rates vary according to the species and seasons. Consequently, chitin can be successfully obtained with a method of a particular preparation based on the source used. Furthermore, physicochemical properties of chitin and chitosan will vary according to the species and prepaiation method. (Cho et al 1998). That chitin and chitosan possess different physicochemical properties may affect their functions. Several studies have revealed that chitin, chitosan and their some derivatives are fairly different according to the used species of dye, water and oil binding capacities. (Muzarelli,1997; No et al7996). Thus, function of chitin and chitosan products must be conducted and used with a great care.

The purpose of this study is primarily to obtain chitin chitosan from shellfish sea wastes in regional and then national platform and then their functional derivatives of them. Another prominent aim is to spread use of chitin and its derivatives in Turkey used commonly in a wide range of sectors in the world. On this occasion, solid wastes that can be component of both pollution will be treated and the products with high added value will be obtained with the production of chitin and its derivatives having a fairly common area ofuse.

As a result, processing solid residues of seafood will be treated and will be converted into the products that will provide gains in economic scale. In this sense, there is no readily study intended for this purpose in Turkey. Therefore, this project will give priority to the studies of treatment of solid wastes of both seafood and damage likely to be posed onto environment and human health by these residues will be precluded.

Moreover, such a study will bring forth to the agenda a possible cooperation in Turkey surrounded by seas on three sides and with from neighbouring countries. Residue collection network of solid seafood products will be established in such countries; their Turkey-based processing and converting them into the products with high added value
will undoubtedly substantially enhance both environmental and economical aspects of the study.
The Project Coordinator has previously a completed project from TUBiTAK i.001 program on this issue. Therefore, given the results obtained therein, production o chitin and its derivatives in higher quality and production economy of this study to be carried out in advance of commercial product will be fundamental deliverable of this product.

Sea fishing contributes more than half of total fisheries in the world and processing and using of them in a rate more than 70 o/o. After all, significant amounts of processing wastes occur in each year and they are fins, head, skin and internal organs. In addition to this, wastes of sea shellfish and shellfish sea animals obtained from sea food processing plants deposit in large quantities. Based on the recent estimates, approximately ZS o/o of sea fisheries in the world, namely, 20 million tons of fisheries waste come into the picture. For this reason, exposing sea food wastes to biotransformation using bioprocess industry poses substantial potential. Chitin and chitosan occupy a prominent seat among these bioactive compounds. (simpson et al., I994). Out of sea shellfish, approximately 3.5 million tons values each year are abandoned on an earth surface by processing industry and such volume gradually increased brings forth the necessity of disposal of these wastes’ (Krrubagaran, 2005). When processing plants wastes are spilled into the sea without being treated, they pose critical predicaments such as pollution, contamination
and adversely affect our environmental health. (Salkr and Krhng, 2004). Treatment of these wastes is of utmost importance in terms of seafood industry and public health.

Byproducts of fishery products are essentially fish oil production, fish mea! fertilizer, animal feed and fish silage. However, recycling of many of the foregoing does not constitute an economic value. The recent studies have shown that bioactive compounds may be obtained from marine crustaceans of shellfish sea animals and fish muscle proteins, collagen and gelatine, fish oil, fish bone, internal organs and sea shellfish. These bioactive compounds can be stated as peptides, oligosaccharides, fatty acids, enzymes, water-soluble minerals and biopolymers as very various compounds from simple to complex to be used in biotechnological and pharmaceutical applications. Furthermore, some of these bioactive compounds have nutraceutical potential and human health supporting benefits. That investigation and presence of valuable bioactive compounds in today’s seafood industry is of an influential issue within byproducts of sea product processing industry. (Kim and Mendis, 2006; Rinaudo, 2005).

The biggest advantage of chitin and chitosan is that they are renewable resources and eco-friendly natural biopolymers. With these properties in recent years it has found uses in many different sectors (synowiecki et al., 2003; Shahidi and Abuzaytoun, 2005).

Chitin and chitosan with its derivatives, glucosamine and N-acetyl glucosamine have found various fields of applications such as artificial skin and wound healing dresses, drug transport systems, cosmetic, nutritional and diet products, enzyme immobilization, heavy metal removal, removal of textile dyes, paper production, agronomic practices, ophthalmology and photography (shahidi and Abuzaytoun, 2005; Rinaudo, 2006).

Chitosan is a naturally occurring polycationic homopolymer and is obtained by Ndeacetylation of chitin. (Tsaih and Chen, 2003; Tsigos et al., 2000). These unique polymers have very diverse functions thanks to their versatile biological activities, biocompatibilities and low toxicity. Thanks to these functions, they have caused an emergence of a new class among physiological materials. (Mourya and Inamdar, 2008).

Chitin is a homopolymer consisting of p-[1- ) linked N-acetyl-D-glucosamine. Easily obtained, abundant in nature and naturally renewable, this polymer is in the second place after cellulose. Natural resources where chitin is present have spread over a wide area. It is usually present in exoskeleton of most vertebrates, some types of algae, insect cuticle and in cell wall of several fungi. (Tsigos et al., 2000; Galed et al., 2005).

Chitosan is a cationic biopolymer comprising randomly dispersed presence of high molecular weight consisting of alkaline N-deacetylation (by deacetylation and generally A-units in chains GICNAC lB$-\-2-acetemido-2-deoxy -p- D-glucopyranosel and D-units GIC [F(1-4)-2-amino-2deoxy-B-D glucopyranose].(fiang and Qiary 2006; Galed et a1.,2005). Even if their molecular structure looks fairly same, their physical and chemical characteristics are very different. Structure of chitin and chitosan is shown in Figure 1 and Figure 2. (Mourya and Inamdar, 2008). Name of chitosan describes a copolymer family containing acetyl units inside in very different fractions than a fully defined compound. ( Tsigos et al., 2000).

chitin-chitosan

Chitin is generally produced from shellfish (crab, shrimp and crayfish) because the whole chitin present in outer skeleton remains as a waste after segregation of meats from food industry. (Galed et a1.,2005).

Chitosan is almost sole cationic polysaccharide in the nature. Addition of various functional groups with chemical modification ensures control of hydrophobic, cationic and anionic properties. (Mourya and Inamdar, Z00g).

Chitin and chitosan are produced with a thermochemical process from crab and shrimp shells’ Since protein, minerals and pigments are present in the structure of shrimp and crab shells, this process is divided into sub-branches for producing pure chitin. These are demineralization (caCo3) and the deproteinizationprocesses. (Tsigos et al., 2000), Acidis used for removal of minerals in chitin extraction with chemical method and base is
used for removal of proteins. (No et al., 1989). % Components of sea shellfish are shown in Table 1.

table1Chitosan is a product obtained by N-deacetylation of chitin and is obtained by deacetylation process; this process is performed by using hot alkali solution. While chitosan deacetylation degree ranges from 40 o/o to 98 % of its molecular weight varies between 5×104 Da and 2×106 Da. (Mourya and Inamdar, 2008). N-deacetylation process is carried out as chemically homogeneous or heterogeneous state. (Tsigos et al. , 2000).

Degrees of depolymerization and deacetylation are substantial parameters changing molecular weight of chitosan. These parameters limit or expand use of chitosan in different applications. (Mourya and Inamd, 2008). All properties of chitosan depend on degree of deacetylation, degree of depolymerization and dispersion during deacetylation of recurring units (Lamarque et al., Z00T).

Until recently, chitosan production was based on thermochemical process procedure conducted under harsh environment conditions. As a result of environmentally unsafe and uncontrolled reaction, the product was not produced as uniform and standard,And it was emerging as having different properties in heterogeneous range. In other words, the products so obtained were polymer communities in physical mixture state having non-specific properties and in high polydispersed structure with randomly deacetylated and different depolymerization (Tsigos et al. , 2000). Therefore, use of chitin deacetylas in chitosan production and development of enzymatic process have
ensured removal of the conditions posing disadvantage in chemical production. However, this method is seen as a fairly costly method in our current conditions.