Probiotička aktivnost bakterija mliječne kiseline izoliranih tijekom spontane fermentacije kupusa

master's thesis

• Title (english): Probiotic activity of lactic acid bacteria isolated during spontaneous fermentation of cabbage
• Author: Marina Bujan
• Mentor: Blaženka Kos (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for Antibiotic, Enzyme, Probiotic and Starter Cultures Technology); Zagreb
• Defense date and country: 2010-11-29, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Tijekom spontane fermentacije kupusa izolirano je 16 gram-pozitivnih, katalazanegativnih i nesporogenih bakterijskih sojeva. Izolirani sojevi bakterija mliječne kiseline bojanjem po Gramu definirani su kao 15 gram-pozitivnih štapića i jedan gram-pozitivni kok. SDS-PAGE elektroforeza ukupnih staničnih proteina te RAPD metoda s početnicom za bakterije mliječne kiseline su pokazale da se radi o 7 različitih sojeva bakterija mliječne kiseline. Fenotipskom identifikacijom API testom, tri su soja identificirana kao Lactobacillus plantarum, jedan kao Leuconosotoc mesenteroides te jedan kao Lactobacillus brevis. Ispitivanjem rasta odabranih bakterijskih sojeva pri različitim koncentracijama natrijevog klorida ustanovljeno je da svi rastu u prisutnosti 4-6% natrijevog klorida što je važno tehnološko svojstvo potencijalnih starter kultura za proizvodnju kiselog kupusa. Istraživanja u okviru probiotičkog koncepta su pokazala da odabrani bakterijski izolati u visokom postotku preživljavaju simulirane uvjete gastrointestinalnog trakta. Ove potencijalno probiotičke kulture pokazale su snažno antimikrobno i bakteriocinsko djelovanje te mogućnost autoagregacije i koagregacije sa srodnim bakterijskim vrstama ili potencijalno patogenim test-mikroorganizmima. Bakterijski sojevi su osjetljivi na većinu ispitanih antibiotika, dok su svi rezistentni na streptomicin i vankomicin. Također su preživjeli proces liofilizacije u visokom broju (postotak preživljavanja iznad 90%), što je značajno s tehnološkog aspekta proizvodnje probiotičkih i starter kultura za industrijsku primjenu.

Abstract (english)

During spontaneous fermentation of cabbage 16 gram-positive, catalase-negative and non-sporogenic bacterial strains were isolated. Isolated lactic acid bacteria strains have been defined as 15 gram-positive bacilli and one as gram-positive coccus by Gram staining. SDSPAGE electrophoresis of total cell protein and RAPD method with primers for the lactic acid bacteria have shown that there are 7 different lactic acid bacteria strains. Their phenotypic identification, performed by API test, has proven that three of them were identified as Lactobacillus plantarum, while one as Leuconosotoc mesenteroides and the last one as Lactobacillus brevis. Examination of growth of selected bacterial strains at different concentrations of sodium chloride have shown that all bacterial strains grow in the presence of 4- 6% sodium chloride, which is an important technological feature of potential starter cultures for the production of sauerkraut. Research in the probiotic concept has shown that selected bacterial isolates survived simulated gastrointestinal conditions in a high percentage. These potentially probiotic bacteria have demonstrated a strong antimicrobial and bacteriocinogenic activity and the possibility of autoaggregation and coaggregation with related bacterial species or potentially pathogenic test-microorganisms. Bacterial strains were sensitive to most antibiotics tested, whereas all of them were resistant to streptomycin and vancomycin. Tested bacterial strains have also survived the freeze-drying process successfully (the percent of survival above 90%), which is very important from a technological point of probiotic and starter cultures production for industrial applications.

• Keywords: bakterije mliječne kiseline; kupus; starter kluture; probiotici; antimikrobno djelovanje; liofilizacija
• Keywords (english): lactic acid bacteria; cabbage; starter culture; probiotics; antimicrobial activity; freeze-drying
• Language: croatian
• URN:NBN: urn:nbn:hr:159:328239
• Study programme: Title: Food Safety Management; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka upravljanja sigurnošću hrane (magistar/magistra inženjer/inženjerka upravljanja sigurnošću hrane)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-08-29 11:37:54