Recovery of chitin and chitosan from shrimp waste by chemical and microbial methods (original) (raw)
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Production of chitin and chitosan from shrimp shell wastes
Journal of the Bangladesh Agricultural University, 2017
A method was developed for commercial scale production of chitin and chitosan in Bangladesh from marine shrimp, P. monodon and freshwater prawn, M. rosenbergii shell and appendages. Chitin is a macro-molecular linear polymer of anhydro N-acetyl glucosamine (N-Acetyl, 2-Amino 2-Deoxy D-Glucose) and chitosan is deacetylated chitin. For production of chitin, fresh shells of P. monodon having initial bacterial load of >10 5 CFU/g sample and peroxide values of >10 mmol free iodine liberated /kg of oil were washed with dilute sulfuric acid. Adhered proteins were removed by washing with low strength alkaline solution and then rinsed with water. Crude chitin thus prepared was treated with concentrated hydrochloric acid and purified chitin was obtained after treating with low strength alkali solution. Water soluble chitosan was prepared by performing a deacetylation process using 50% NaOH (w/w) at 100 o C for 4-5 hours and then washed, dried and ground. For purification of chitin and chitosan, a series of experiments were conducted to optimize the level of NaOH concentration and time and temperature schedule of demineralization and deproteinization/deacetylation. A high temperature-short time schedule obtained best quality chitin and chitosan. Both subjective and objective methods were used for the testing of quality and purity of chitin and chitosan. Comparative studies between the quality of products from different components of the shell and from different shrimp/prawn species showed that both chitin and chitosan obtained from M. rosenbergii shell were better compared to those of P. monodon in terms of extractability, deacetylation, and color. Shells obtained better product compared to shrimp appendages. The study suggests that chitin and chitosan can be produced in existing shrimp/prawn processing plants of the country with the simple renovation.
Biological method of chitin extraction from crustacean shells is an advanced and new technique which involves extraction of long chain carbohydrate polymer chitin by using lactic acid bacteria and it produces a good quality end product. This eco-friendly and low cost technique requires 24-48 hours old Lactobacillus inoculums for fermentation. The 10% culture inoculums is added with crustacean shells along with same quantity of carbon sources for 180 hrs incubation followed by filtering and the obtained solid cake i.e. chitin is dried in hot air oven. The additional advantage of this technique is production of liquid fraction which is rich in protein and can be used for human and animal feed. However, this method is still limited in laboratory condition as because demineralization and deproteinization have not yet reached up to the desired yields as compared to chemical method.
Comparison of the Quality of Chitin and Chitosan from Shrimp, Crab and Squilla Waste
Current World Environment
Chitin and Chitosan obtained from the crustaceans are having more biological value such as physiological compatibility, non-toxicity, bio digestibility, adsorption and chelating capacity. These biological values of chitosan depend on the quality parameters which are directly related to the source of the raw material. In this study, three commercially available crustacean shell waste such as shrimp, crab and squilla were used for the extraction of chitin and chitosan. The chemical treatment of demineralization, deproteinization and deacetylation were used for the production of chitosan. The viscosity quality parameter of the shrimp chitosan (5300cPs) was better than the crab and squilla chitosan. It is due the high solubility (97.65%) of the shrimp chitosan in 1% acetic acid. The degree of deacetylation of the shrimp chitosan (81.24%) directly relates the solubility of the chitosan. The chitosan with these quality parameters considered to be the excellent biological value. The yield ...