Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Production of B-Galactosidase Using Lactic Acid Bacteria and Optimisation of Fermentation Parametters(Izmir Institute of Technology, 2007) Üstok, Fatma Işık; Tarı, Canan; Tari, Canan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyFood grade thermostable B -galactosidase preparations are always in demand for a number of industrial applications. Thermostable -galactosidases from LAB having a neutral pH-optimum can be safely used to reduce the lactose content of milk for the lactose intolerant people. In this study, -galactosidase was produced with high productivities by novel Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains isolated from traditional Turkish yogurt samples in Toros mountain region. A full factorial statistical design was used separately for Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains in screening experiments. Among the strains, Lactobacillus delbrueckii subsp. bulgaricus 77 and Streptococcus thermophilus 95/2 were found to have high potential for B-galactosidase and lactic acid production, therefore these were used in the further optimisation studies.The efficiency of different cell disruption methods was investigated on the extraction of -galactosidase. Among these, lysozyme enzyme treatment was determined as the most effective method. Optimisation studies were carried out using response surface methodology to optimize fermentation conditions for pure strains as well as for mixed ones. Therefore, symbiotic relationship between St 95/2 and Lb 77 were investigated as well. Symbiotic relationship provided 39% and 6.1 % more -galactosidase activity and 44 % and 9.73 % more lactic acid production when compared to the optimisation results of pure strains Lb 77 and St 95/2, respectively.Overall, characterization studies showed that enzymes obtained from these strains can be considered as food grade and thermostable since they are obtained from thermophile, food originated novel LAB of local microflora.Master Thesis Transformation of Aspergillus Sojae With Vitreoscilla Hemoglobin Gene(Izmir Institute of Technology, 2010) Bardakçı, Betül; Tarı, Canan; Tari, Canan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyAspergillus sojae known as koji mold is a non-aflatoxigenic fungus, designated with a GRAS status by FDA. This study considers the transformation of A. sojae with Vitreoscilla hemoglobin gene. Vitreoscilla hemoglobin is the bacterial hemoglobin, which enhances the oxygen transfer under microaerophilic conditions. Since industrial fungal fermentation with the high demand for oxygen are accounted to face oxygen limitations during the production of value added products like enzymes, antibiotics and organic acids; oxygen supply becomes an enormous problem to be solved by the manufacturers. To overcome this problem, an alternative solution using the vgb gene of Vitreoscilla and recombinant DNA technology and taking the A. sojae organism as model organism was proposed. The product of interest in this study was the exopolygalacturonase enzyme known to have wide applications in food, pharmaceutical, textile and paper industries. Here vgb gene was tried to be introduced to A .sojae via both protoplasting and electroporation methods. For transformation process vgb gene was cloned initially into plasmid ANIp4. For the selection of transformed A. sojae cells, uridine auxotrophic mutants were tried to be selected after UV mutagenesis. However, using a procedure based on selection of uridine supported growth did not result in A. sojae pyrG mutants. The success of transformation was initially observed by means of PCR analysis and agarose gel electrophoresis, later this was try to be confirmed by sequence analysis and agarose gel electrophoresis. However, due to the contamination problems accounted in the procedures the transformation with both methods could not be assured.Master Thesis Chemical Composition Analysis of Agroindustrial Waste and Their Potential Usage in Bio-Ethanol Production(Izmir Institute of Technology, 2011) Üçüncü, Can; Tarı, Canan; Tari, Canan; 03.08. Department of Food Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyBetween the year 2000 and 2008 the amount of fruits and vegetables used in fruit juice industry were 4918400 tons in Turkey. Thus, % 15-30 of a fruit is pomace, high amount of pomace appears as waste in fruit juice industry every year. Some of these pomaces could be candidates as potential fermentation media for bioethanol production. The aim of this study was in first step the optimization of the hydrolysis conditions using statistical methods and then the selection of the best hydrolysate for bioethanol production using the fungus Tricoderma harzianum. In the optimization study the factors were temperature, time, solid liquid ratio and acid percentage whereas the responses were furfural, hydroxymethylfurfural, glucose, xylose, galactose, arabinose and total reducing sugar yield. According to the results of the screening process, the hydrolysis step was carried out at a temperature and time of 126 ï‚°C, 40 min for apricot pomace and 110 ï‚°C, 40 min for peach and apple pomace. In the optimisation step and levels of the other factors were enlarged. The highest reducing sugar yield during optimization was 31% for apple, 49.16% for apricot and 52.44% for peach pomace. These results indicated that these pomaces hold certain potential for bioethanol production. Three different incubators (CO2, static and non-static) were used for the fermentation process. Tricoderma harzianum grown aerobically in two different media (YPM and YNB) inoculated in apple hydrolysates was used in each incubator for bioethanol production. The highest ethanol production was 1.67g/L in non-static incubator with the culture grown in YNB media.