physicochemical and functional properties of crawfish chitosan as ...

degree of deacetylation, and molecular weight, but significantly higher viscosity value than those
of commercial chitosan.
2.6 Applications of Chitosan
The poor solubility of chitin is the major limiting factor in its utilization. Chitosan is
considered as a potential polysaccharide because of its free amino groups that contribute
polycationic, chelating, and dispersion forming properties along with ready solubility in dilute
acetic acid. Chitosan possesses exceptional chemical and biological qualities that can be used in
a wide variety of industrial and medical applications. Some of these are listed below (Table 1)
(Knorr, 1984; Muzzarelli, 1977).
2.6.1 In the Wastewater Treatment
The prime commercial applications for chitosan currently is in industrial wastewater
treatment since chitosan carries a partial positive charge and binds to metal ions, thus makes the
metal ions removal from waste streams or contamination sites easier (Asano, 1978). In terms of
utilization, crawfish chitosan as a coagulant for recovery of organic compounds in wastewater
was demonstrated to be equivalent, or superior to, the commercial chitosans from shrimp and
crab waste shell and synthetic polyelectrolytes in turbidity reduction (No and Meyers, 1992).
Table 1. Applications of Chitosan
Wastewater Removal of metal ions, flocculant/coagulant, protein, dye, amino acids
Treatment
Food Industry Removal of dye, suspended solids, preservative, color stabilization, food
stabilizer, thickener and gelling agent, animal feed additive, etc.
Medical Wound and bone healing, blood cholesterol control, skin burn, contact
lens, surgical sutures, dental plaque inhibition, clotting agent, etc.
Agriculture Seed coating, fertilizer, controlled agrochemical release
Cosmetics Moisturizer, face, hand, and body creams, bath lotion, etc.
Biotechnology Enzyme immobilization, protein separation, cell recovery,
chromatography
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