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Document Type:Latin Dissertation
Language of Document:English
Record Number:52568
Doc. No:TL22522
Call number:‭NR13051‬
Main Entry:Nesreen Samir Mahmoud
Title & Author:Novel biotechnological approach for the production of chitin and de -icing agentsNesreen Samir Mahmoud
College:Dalhousie University (Canada)
Date:2005
Degree:Ph.D.
student score:2005
Page No:473
Abstract:This study proposed the use of two potent pollutant waste materials (cheese whey and shrimp shells) for the production of three value-added products: salts of organic acids (useful as de-icing agents), chitin (for use in the medical, biomedical and pharmaceutical industries) and protein liquor (useful as protein supplement in animal feed). The study was carried out in four phases. In the first phase, the applicability of on-line sterilization of cheese whey using ultraviolet radiation (UV) was investigated. It was found that despite the high turbidity of the cheese whey, UV radiation can be used for cheese whey sterilization if the proper flow thickness and residence time are used. A residence time of 0.8 h was required to completely destruct a microbial population of 5.95 x 106 cells/mL using tubular UV reactors of 6 mm gap size. Fouling was found to be a major limitation in tubular UV reactors when used for extended period of time as a result of lamp heat generation. Adsorption and direct ion exchange were the most likely fouling mechanisms. In the second phase, the applicability of tetrazolium salt triphenyltetrazolium chloride (TTC) for biomass quantification was investigated. For dehydrogenase activity measurements, the pH of the samples and the incubation temperature should not be higher than 9 and 60°C in order to ensure that the TTC reduction is caused only by the biochemical reaction. The presence of copper in the medium caused a reduction in the red color intensity due to the formation of formazan copper complex. The optimum TTC-test conditions for biomass quantification of Aspergillus niger in liquid growth medium were TTC concentration of 20 g/L, a pH of 9, a temperature of 55°C, and incubation time of 3 h and anaerobic conditions. The age of A. niger cells affected the TF yield. Shrimp shells contributed to the reduction of the TTC and therefore TTC-test can be used for A. niger quantification during solid-state fermentation of shrimp shells with some limitations. In the third phase, a biotechnological approach was used for the deproteinization of shrimp shells using the fungus Aspergillus niger in solid-state fermentation. A. niger was able to produce proteases in the presence of shrimp shells and galactose as a carbon source, thus causing the deproteinization of the shrimp shells. In the forth phase, the applicability of using lactic and acetic acids for the demineralization of microbially deproteinized shells was investigated. (Abstract shortened by UMI.)
Subject:Applied sciences; Biological sciences; Biotechnological; Chitin; Deicing; Agriculture; Agricultural engineering; Food science; 0539:Agricultural engineering; 0473:Agriculture; 0359:Food science
Added Entry:Dalhousie University (Canada)