3710

3510

كارشناسي ارشد

مهندسي شيمي

اصفهان : دانشگاه صنعتي اصفهان، دانشكده مهندسي شيمي

1386

دوازده، 65، [II] ص: مصور، جدول، نمودار

ص. ع. به فارسي و انگليسي

محمد جعفر طاهرزاده، كيخسرو كريمي

17/7/86

كيقباد شمس، مهدي كديور

1396/02/25

كتابنامه

مهندسي شيمي

مهندسي شيمي

ID3510

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

AbstractChitosan a polymer of glucosamine is industrially produced by chemical deacetylation ofchitin from shellfish Cell wall of zygomycetes is an alternative source for production ofchitosan In fungal cell wall chitosan is produced by enzymatic deacetylation of chitin The chitosan is a polycationic polymer and therefore antimicrobial activity is one of themost important characteristics of this polymer In this study we used a new method forchitosan extraction which is via hot dilute sulfuric acid treatment It is a new method forextraction of chitosan from cell wall material of fungi developed by biotechnologyresearch group at University of Bor s in Sweden and this work was accomplished incollaboration with them Sulfuric acid extraction method was used to determine chitosanyield in cell wall of three different strains Rhizopus oryzae Mucor indicuss Rhizonucorpucillus obtained from culture collection of university of Goteborg Sweden The ability offungi for production of chitosan was examined at different growth phases The resultsindicated that within less than 24 h the pH of the culture media of all fungi decreased frominitial value 5 5 to less than 3 Without any control of the pH maximum extractablechitosan from one Kg of dry biomass R oryzae was about 52 4 g M indicus 36 5 g and R pusillus 27 8 g within 6 days Phosphates and N acetyl glucosamine were the othercompounds measured in this study Results showed that R pusillus was the most activefungus for production of chitin and was able to produce 136 4 g chitin per kg dry biomassand its phosphate content was less than 10 of biomass for each three strains Since R oryzae had the highest chitosan yield the effect of pH and salt concentration were alsostudied on the chitosan yield from cell wall of this microorganism The results showed thatat pH 6 5 chitosan and phosphate yields are 3 5 and 2 9 times higher than the samecondition at pH 3 5 respectively Furthermore if the salt concentration was less than 10g l with increasing the salt concentration chitosan yield from cell wall decreased whereaschitosan yield increased if the salt concentration was above this value Antimicrobialproperties of fungal chitosan extracted form R oryzae was studied against three typicalhuman pathogenic microorganisms Escherichia coli Klebsiella pneumoniae andStaphylococcus aureus The minimum bactericidal concentration MBC of the fungalchitosan was 300 500 and 700 ppm for S aureus E coli and K prenumoniae respectively The antimicrobial activity of fungal chitosan was lower than that ofcrustacean shells chitosan which had MBC of less than 100 ppm for the above mentionedbacteria Furthermore similar to crustacean shells chitosan fungal chitosan exhibitedbetter inhibitory effects against gram positive compared to gram negative bacteria

محمد جعفر طاهرزاده، كيخسرو كريمي

كيقباد شمس، مهدي كديور