Shellfish chitin waste

Cosio IG, Fisher RA, Carroad PA. Bioconversion of shellfish chitin waste waste pretreatment, enzyme production, process design and economic analysis. J Food Sci 1982 47 901-905. 

Bioconversion of Shellfish Chitin Waste. In the quest of finding ways to utilize tne nutrients m shellfish processing waste, another avenue has been discovered. A process has been developed which bioconverts shellfish chitin to yeast single-cell protein (96-98). The product of this process is a protein-rich material wRTcfT can be used as an animal and aquaculture feed supplement. Since chitin s chemical structure is nearly similar to cellulose, the concept of this process was inspired from the bioconversion... 

Carroad P.A., Tom R.A., 1978. Bioconversion of shellfish chitin wastes Process conception and selection of microorganisms. J. Food Sci. 43 1158-1161. 

Chang, W.T., Chen, Y.C., and Jao, C.L. 2007. Antifungal activity and enhancement of plant growth by Bacillus cereus grown on shellfish chitin wastes. Bioresour. Technol., 98 1224—1230. 

Chitin, a polysaccharide similar to cellulose, is Earth s second most abrmdant polysaccharide (after cellulose). It is present in the cell walls of fungi and is the fundamental substance in the exoskeletons of crustaceans, insects, and spiders. The structure of chitin is identical to that of cellulose, except for the replacement of the OH group on the C-2 carbon of each of the glucose units with an -NHCOCH3 group. The principal source of chitin is shellfish waste. Commercial uses of chitin waste include the making of edible plastic food wrap and cleaning up of industrial wastewater. 

One approach to extracting valuable compounds from shellfish processing waste is through the use of marine microorganisms in a procedure referred to as solid state (substrate) fermentation, or SSF. SSF may prove to be an economically advantageous tool for the production of certain compounds from marine waste. For example, the marine fungus Beauveria bassiana can be used to produce chitinase from chitinous prawn waste. Without the fungus, this conversion step normally accounts for 12% of the... 

Currently, commercial chitin and chitosan are extracted from industrial shellfish processing wastes (shrimp, crab, lobster). The seasonal character of those raw materials and the variability of the composition of the organisms make the process of chitin extraction rather expensive with low reprodudbillty. Moreover, they are subjected to environmental variations that impact on the products supply and quality [14,40,116]. Chitin is extracted from crustacean shells by the use of strong adds and/or bases that can cause deacetylation and depolymerization of chitin [119]. Alternative methods include the use of enzymes or proteolytic microorganisms (e.g.. Pseudomonas malto-philia, Bacillus subtilis. Streptococcus faecium, Aspergillus oryzae) that hydrolyze shellfish proteins and leave the associated chitin intact [119]. 

Hattis, D. Murrayt A. E. Industrial Prospects for Chitin and Protein from Shellfish Waste MIT Sea Grant Report No. MIT-SG-ZV-J, 1977 pp 9y. 

A minor source of carbohydrates that should be mentioned, nevertheless, is chitin, a polymer of N-acetyl-D-glucosamine (see Fig. 8.2 c) that resembles cellulose in its structure and general behavior. Chitin is extracted at a 150 kt a-1 scale from shellfish waste [18], which is a tiny fraction of the amount that grows and decays every year. 

Subasinghe, S. 1999. Chitin for shellfish waste—health benefits overshadowing industrial uses. Infofish Int. 3, 58-65. 

Chitin is a homopolymer of AT-acetyl-D-glucosamine residues and is a major structural component in the exoskeletons of crustaceans, mollusks, arthropods, and the cell walls of numerous fungi and algae. Owing to its widespread presence in both terrestrial and aquatic organisms, chitin is second only to cellulose as the most abundant biopolymer on the Earth (Shahidi and Abuzaytoun, 2005). On a dry weight basis, shrimp, crab, lobster, prawn, and crayfish have been reported to contain between 14% and 35% chitin, while deproteinized dry shell waste of Antarctic krill contains approximately 40% crude chitin (Haard et al, 1994). Crustaceans are the primary sources of chitin used in industry. Chitin can be extracted from shellfish and crustacean waste by mixing with a dilute add to induce demineralization, followed by a deproteini-zation step in a hot alkaline solution (Synowiecki and Al-Khateeb, 2003). 

The isolation of chitin from shellfish waste consists of three steps deproteinization (DP), demineralization (DM), and decolorization (DC) whereby the order of the first two steps is generally considered irrelevant if protein or pigment recovery is not an objective (Shahidi and Synowiecki 1991). Chitin is further deacetylated (DA) to make chitosan or other products for a wide array of applications. Both chemical and enzymatic non-continuous batch methods are widely used on an industrial scale for the production of chitin, chitosan, and COS. 

Several procedures for the preparation of chitin and chitosan from different shellfish wastes have been developed over the years, some of which form the basis of the chemical processes used for the industrial production of chitin and derivatives (Femandez-Kim 2004). A representation of current industrial chitin processes are sununarized in Figure 2.3. Industrial techniques for chitin and chitosan extraction from different shell waste streams normally rely on harsh chemical processes due to covalent associations with other shell constituents. These methods generate large quantities of hazardous chemical wastes and partial DA of chitin and hydrolysis of the polymer may occur, leading to inconsistent physiological properties in the end products (Andrade et al. 2003, Kim and Mendis 2006). 

While most processes for the production of chitin (and derivatives) from shellfish wastes entail a batch production using chemical, enzymatic, or fermentative methods, some research on novel techniques has been performed. 

Hayes, M., Carney, B., Slater, J., and Briick, W. 2008. Mining marine shellfish wastes for bioactive molecules Chitin and chitosan—Part A Extraction methods. Biotechnol J. 3 871-877. 

Johnson, E.L. and Peniston, Q.P 1982. Utilization of shellfish waste for chitin and chitosan production. In Chemistry Biochemistry of Marine Food products, eds. G.J. Martin, C.E. Hebard, and W.R. Ward, pp. 514—522. Westport, CT AVI Publishing Co. 

Revah-Moiseev, S. and Carroad, A. 1981. Conversion of the enzymatic hydroxylate of shellfish waste chitin to single-cell protein. Biotechnology and Bioengineering 23 1067-1078. 

Chitosan is deacetylated chitin that is swollen with water and dissolves in a water acetic acid mixture. This polymer is produced commercially from the base-catalyzed deacelylatlon of shellfish waste by Protan (Drammen, Norway). Chitin and chitosan exhibit good mechanical properties as well as low permeabilities ... 

In the past, a small quantity of shell waste was utilized for animal feed or chitin isolation [19]. Thus, the processing of shellfish was a major concern for environmental pollution. Nowadays, this problem has been overcome to a certain extent... 

---