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dc.contributor.advisorTari, Cananen
dc.contributor.authorÜstok, Fatma Işıken
dc.date.accessioned2014-07-22T13:52:31Z
dc.date.available2014-07-22T13:52:31Z
dc.date.issued2007en
dc.identifier.urihttp://hdl.handle.net/11147/3859
dc.descriptionThesis (Master)--Izmir Institute of Technology, Biotechnology, Izmir, 2007en
dc.descriptionIncludes bibliographical references (leaves: 90-97)en
dc.descriptionText in English; Abstract: Turkish and Englishen
dc.descriptionxiii, 120 leavesen
dc.description.abstractFood 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.en
dc.language.isoeng
dc.publisherIzmir Institute of Technologyen
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subject.lccTP248.L3 U88 2007en
dc.subject.lcshLactic acid bacteriaen
dc.subject.lcshLactose intoleranceen
dc.subject.lcshLactobacillusen
dc.subject.lcshBeta-galactosidaseen
dc.subject.lcshFermentationen
dc.titleProduction of B-galactosidase using lactic acid bacteria and optimisation of fermentation paramettersen
dc.typemasterThesisen
dc.contributor.departmentIzmir Institute of Technology. Biotechnology and Bioengineeringen
dc.relation.publicationcategoryTezen_US


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