Master Degree / Yüksek Lisans Tezleri

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

Browse

Filters

2004 - 200942020 - 20231

Settings

Subject: search.filters.subject.Polygalacturonase

Search Results

Now showing 1 - 5 of 5
  • Master Thesis
    Crude Pectinolytic Enzymes Production in Fed-Batch Shake Flask Cultivation
    (01. Izmir Institute of Technology, 2023) Esen, Büşra Nur; Uzuner, Sibel; Uzuner, Sibel; Taşkent Sezgin, Hümeyra
    The use of waste in the production of enzymes, which is one of the products with high added value, is one of the right strategies to reduce the production cost of the product and sustainability movement. In this study, the production of polygalacturonase (PGase) and pectin lyase (PLase) enzymes from Bacillus subtilis ATCC 6633 in fed batch submerged fermentation, the conditions and composition of the fermentation medium and the effects of pretreatment methods (thermal, thermo-chemical, microwave assisted dilute acid (MW- DA)) on the conversion of fermentable sugar from black carrot pulp were investigated. The MW-DA was chosen the best with higher fermentable sugar content (FSC). The three different powers (300, 600, 850 W) and 3 different treatment time (30, 60, 90 s) were examined by Taguchi design. The highest FSC was found at 300 Watt for 30 seconds. MW-DA followed by ES produced the most fermentable sugar (0.493 g/g, 87.3% conversion). The amount of fermentable sugar was enhanced from 15.8% to 87.3% when MW-DA treatment is combined with enzymatic saccharification (ES). Yeast extract, whey and pea protein were examined as nitrogen sources. According to the enzyme activity results obtained, the fermentation medium was modified with pea protein. Certain concentrations (2.5%, 5%, 10%, 15%) were fed to the fermentation medium. The highest PGase activity was determined at the 15% feed concentration and 72th hours (164.34±2.26 U/L) whereas the highest PLase activity was obtained at 72th hours (188.22±1.72 U/L) at 5% feed concentration.
  • 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
    Investigation of the Effects of Dissolved Oxygen Concentration, Aeration and Agitation on the Morphology and Rheology in Submerged Fungal Fermentation
    (Izmir Institute of Technology, 2007) Öncü, Şelale; Ünlütürk, Sevcan
    The effects of pH, agitation speed, dissolved oxygen tension (DOT) and aeration, significant in common fungal fermentations, on the production of polygalacturonase (PG) enzyme and their relation to morphology and broth rheology were investigated in a batch bioreactor using Aspergillus sojae which has no available literature report on the pectinase production. All four factors were effective on the response parameters under study. An uncontrolled pH increased biomass and PG activity by 27% and 38%, respectively compared to controlled pH (pH 6). pH did not significantly affect the broth rheology but created an impact on the pellet morphology. Similarly, the maximum biomass obtained at 500 rpm and at 30h was 3.27 and 3.67 times more than at 200 and 350 rpm, respectively. The maximum enzyme productivity of 0.149 U ml-1 h-1 was obtained at 200 rpm. Non . Newtonian and pseudoplastic broth rheology was observed at 500 rpm agitation speed. Furthermore, a DOT range of 30-50% was essential for maximum biomass formation, whereas only 10% DOT was required for maximum PG synthesis. Non . Newtonian shear thickening behavior (n>1.0) was depicted at DOT levels of 10% and 30%, whereas, non-Newtonian shear thinning behavior (n<1.0) was dominant at 50% DOT. When 2.5 l/min aeration experiment was investigated detaily; it was determined that at about 21st hour, polygalacturonase production approaches its maximum (1.49 U) and pellets are smaller, high in number. At 48th hour; polygalacturonase production declines to zero, biomass reaches its maximum and pellets are big (average pellet size is 1.94±0.58 mm) and fluffy with compact centers. At the end of fermentation (96.hour), fermentation medium is close to Newtonian. The overall fermentation duration (50-70h) was considerably shorter as opposed to common fungal fermentations revealing the economic feasibility of this particular process. As a result this study not only introduced a new strain with a potential of producing a highly commercially significant enzyme but also provided certain parameters significant in the design and mathematical modelling of fungal bioprocesses.
  • Master Thesis
    Isolation and Molecular Characterization of Extracellular Lipase and Pectinase Producing Bacteria From Olive Oil Mills
    (Izmir Institute of Technology, 2004) Altan, Asena; Yenidünya, A.Fazil
    Lipases and pectinases are industrially important enzymes. These enzymes are produced by a variety of microorganisms. However there are few studies on the production of these enzymes by thermoacidophilic Bacillus species. The aim of this research was the isolation of extracellular lipase and pectinase producing thermoacidophilic Bacillus from olive oil mills and their identification by phenotypic tests, 16S-ITS rDNA RFLP and DNA sequencing. Eighty-six thermoacidophilic strains were isolated from olive, olive husk and soil contaminated with alpechin collected within different olive oil mills in Ayvalık. The strains were screened for the presence of 5 extracellular enzyme activities. These were lipase, pectinase, amylase, xylanase and cellulase. In total, 69 lipase (Tween 20 as subtrate), 32 pectinase and 68 amylase activities were detected. None of the isolates were able to produce xylanase or cellulase enzyme. All of the isolates were Gram(+) endospore forming rods, thus they were identified as Bacillus sp. Taq I was used for 16S-ITS rDNA based RFLP. The isolated strains were clustered into four groups by Taq I restriction profiles of 16S-ITS rDNA. One representative isolate among the members of each of the 16S-RFLP homology groups was chosen and used for 16S rRNA gene partial sequence analysis. Sequencing results were submitted to GenBank. So far the indicated accession numbers were obtained: AY601903 (isolate H 22 of G-3, 679 nucleotides), AY606276 (isolate S1 of G1, 330 nucleotides)
  • Master Thesis
    Production of Pectinase Enzyme From Aspergillus Sojae Batch and Fed-Batch Systems
    (Izmir Institute of Technology, 2008) Doğan, Nergiz; Tarı, Canan
    Commercial preparations of pectinases derived from fungi are well known to have high biotechnological value in the industry. For this purpose, polymethylgalacturonase (PMG) and polygalacturonase (PG) were produced with high productivities by Aspergillus sojae ATCC 20235 by using low cost carbon (Maltrin) and nitrogen (Corn Steep Liquor, CSL) sources. There is no literature report to best of our knowledge on the fed-batch production, purification and characterization of polygalacturonase using this microorganism.In this study batch fermentation was carried out in order to obtain the crude PG and to establish a baseline for the forth coming fed-batch experiments. The crude PG was partially purified using three-phase partitioning as an emerging bioseparation technique and characterized with respect to its biochemical and thermal properties. These studies showed that this enzyme holds a great potential to be a good candidate for various industrial applications. To optimize fed-batch fermentation conditions, response surface methodology (RSM) was performed using face-centered central composite design. As a result, maximum PG activity (20.61 U/ml) and maximum biomass (34.23 g/l) were obtained at high maltrin (150 g/l) and high CSL (10 g/l) concentrations when the repeated feeding was done at 48th and 72nd hours. Maximum PMG activity (16.76 U/ml) was also achieved at higher maltrin and higher CSL concentrations at a feeding time of 72nd hours. Fed-batch fermentation has been successfully used to increase PG (33.74%) and PMG (23.96%) activities from Aspergillus sojae. Finally, agar diffusion method was adapted as a rapid method for the selection of high pectinase producer in the strain improvement study.