Abstract:
Chitasan is a polysaccharide derived from the deacetylation of chitin. Chitin canmostly be found in the exoskeleton of crustaceans such as crab or shrimp shells and in cell wallsof certain h g i . Chitosan and its derivatives are valuable for various applications, such as inmedical, anticoagulant, antiviral, antitumor and food enhancer.Aspergilltcs niger is a fungus generally used in critic acid production. Large amount ofA. niger cells is discarded after the fermentation process. However, the major component ofchitin in cell walls of A. niger can be deacetylated to chitosan. In this work, the deacetylation ofcbitin from A. niger was studied and the derived chitosan was characterized for percentage ofdeketylation (%DD), intrinsic viscosity and molecular weight. The result was found that thedeacetylation of chitin in fungal cell walls by boiling in NaOH 40% conc. at temperature95k2 OC for 24 hours a d the dissolution of chitosan from the deacetylated solution by aceticacid 2% were tlre optimal conditions. Chitosan was extracted from A.niger produced 0.585 gll or9.6% dry cell weight. Chitosan was extracted from microorganism's industrial produced 1.12%dry waste,Investigation of the infrared spectrum of fungal chitosan was isolated from A.nigerand microorganism's industrial give important function group similar to chitosan from shell atpeak of N-H at 1550 om-', peak of C-0 at 1650 cmW'anpde ak of CH, at 2900 cm-'Physical properties of chitosan from A, niger were characterized. The molecularweight was in the range of 40000 - 50000 Dalton, the intrinsic viscosity was around 0.88 - 1.04dVg and percentage DD was approximate 98-99%. Physical properties of chitosan fromindustrial microbial waste were characterized. The percentages DD approximate 94%. Theintrinsic viscosity could not measured. The color of extracted chitosan was brown.