Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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2006 - 200912010 - 20121

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Author: search.filters.author.Tarı, CananSubject: search.filters.subject.Fermentation

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  • Master Thesis
    Effect of the Morphology of Aspergillus Sojae on Pectinase Enzyme and the Optimization of Fermentation Conditions
    (Izmir Institute of Technology, 2006) Göğüş, Nihan; Tarı, Canan
    The control of the morphology of fungi needs great attention for the optimal potential production of the product. For this purpose Aspergillus sojae ATCC 20235, which has no available literature report on the pectinase production, is used as a model in the determination of the optimum regions for maximum polygalacturonase synthesis and biomass formation with desired pellet morphology by using low cost carbon and nitrogen sources. Firstly, a full factorial statistical design, with the factors of, two taxonomically different strains, seven types of seed culture formulations (slants) and two types of fermentation media were used to investigate the effect of these parameters on the polygalacturonase (PG) production. According to statistical analysis, factors of strain types and fermentation media and the interaction between them were found significant on the enzyme activity. Aspergillus sojae in a complex media, inoculated with a seed culture prepared from molasses resulted in maximum PG activity (0.2 U/ml). Then, a two step optimization procedure with four factors (concentrations of maltrin and corn steep liquor (CSL), agitation speed and inoculation ratio) was used to investigate the effect of these parameters on the PG activity, mycelia growth (biomass) and morphology (pellet size) of Aspergillus sojae. According to the results of response surface methodology (RSM), concentrations of maltrin, CSL and agitation speed were significant (p<0.05) on both PG synthesis and biomass formation. As a result, maximum PG activity (13.5 U/ml) was achievable at high maltrin (120 g/l), low CSL (0 g/l), high agitation speed (350 rpm) and high inoculation ratio (2x107 total spore). The diameter of pellets ranged between 0.05-0.63 cm. The second optimization step improved the PG activity by 74 % and the biomass by 40 %. Furthermore characterization of the enzyme with respect to its optimum pH and temperature and the effect of these on the stability were considered. Determination of the thermal inactivation constant with its inactivation energy and the substrate specificity constant were estimated.
  • Master Thesis
    Bioethanol Production From Fungal Sources Using Low-Cost Agro-Industrial Waste Products
    (Izmir Institute of Technology, 2012) Evcan, Ezgi; Tarı, Canan; Özen, Fatma Banu
    In recent years, the rapid increase in environmental problems, greenhouse gas emissions, fuel prices and the unlimited consumption of fuel stocks made people search for some alternative energy sources. Bioethanol is one of the most popular alternative sources with its many beneficial features. Considering the sugar content of fruit pomaces, which are the waste of fruit juice industry, are very convenient and cheap fermentation raw materials for production of bioethanol. The aim of this study was to create a renewable alternative for fossil fuel and to provide a viable solution to multiple environmental problems simultaneously creating a sink for waste utilization and optimize bioethanol production from apple pomace hydrolysate using Trichoderma harzianum, Aspergillus sojae and Saccharomyces cerevisiae by statistical methods. Here, screening and optimization steps were conducted in order to determine the significant factors and their optimum levels. Factors such as inoculation rate of A.sojae and T.harzianum and agitation speed were considered as factor variables, whereas the response variable was bioethanol production. According to the results of the screening process, inoculation rate of S.cerevisiae was fixed as 4% and aeration method as vented. In the optimization step, levels of the other factors were enlarged. The highest bioethanol production and yield on substrate were 8.748 g/l and 0.946, respectively. Higher concentrations of inoculation rates of T.harzianum and A.sojae (6%) and agitation speed of 200 rpm led to maximum bioethanol production. Furthermore, the results pointed out that using cocultures because of its synergistic interactions is an effective way for production of bioethanol.