Abstract:
The ob.lcctives of this work were to investigate the optimum conditions for extractionchitosan from fu~lgi cultivated by molasses i.e., (1) concentration and composition of molassesfor cultivating fungi, (2) the optimum harvesting time for biomass, (3) the optimum conditionsfor dcprotinization by NaOH, (4) thc optimun conditions to extract chitosan by acetic acid and( 5 ) the physical properties of chitosan extracted from Rhizopus microsporus NRRL 3671,Rhizopzls oryzac lJPCC 3356, M u m sp. TISTR 3298.Fungal strains of Rhizopus ~nicrosporus NRRL 3671, Rhizopus oryzae UPCC 3356 andMucur sp. TISTR 3298 demonstrated rich growth in thc molasses at the concentration of200 ppm. The yield of biomass of the fungi ci~ltured by molasses and by PDB after 4 days and 7days was not sigri~ficantly different. However the degree of deacetylation of the fungi harvestedafter 4 days was higher than thosc harvested after 7 days. The highest level of chitosanproduction was 45.9 mg chitosan/ g dry ccll weight extracted from Rhizopus oryza UPCC 3356cultured in molasses by IN NaOH at 121 OC for 60 minutes followed with 2 percent acetic acid60 OC reflux for 8 hours. The physical properties of chitosan from Rhizupus oryzae UPCC 3356cultivated by molasses were characterized. The degree of deacetylation was approximate83-87 percent and ash content was 2-3 percent.Infrared spectrum of chitosan extracted from Rhizopus microsporus NRRL 3671,Rhizopus oryzile UPCC 3356 and Mucur sp. TISTR 3298 illustrated peaks of functional groupsof N-H at 1560 cm-1and peak of C=O at 1030 cm'-1 which are identical to those of chitosansamples.Therefore we can conclude that the extract was chitosan