Funkcionalnost probiotičkih bakterija iz roda Lactobacillus

master's thesis

• Title (english): Functional properties of probiotic bacteria of Lactobacillus genus
• Author: Ivona Županić
• Mentor: Jasna Novak (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: 2014-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Pojedini bakterijski sojevi iz roda Lactobacillus zbog dokazanih korisnih učinaka na zdravlje domaćina primjenjuju se kao probiotici. U ovom radu selekcionirano je 11 različitih pročišćenih sojeva bakterija iz roda Lactobacillus iz probiotičkih pripravaka te je provedena njihova reidentifikacija i analiza funkcionalnih svojstava in vitro. Za međusobno razlikovanje probiotičkih sojeva korištena je RAPD metoda utemeljena na PCR reakciji provedenoj sa specifičnim početnicama za rod Lactobacillus. Da se radi o BMK iz roda Lactobacillus protvrdili su i rezultati analize konvencionalnim mikrobiološkim metodama, parametri proizvodnje mliječne kiseline i promjene pH vrijednosti, te fermentacijski profili šećera određeni pomoću API 50 CHL testa. Prema rezultatima E-testa, odabrani sojevi su osjetljivi na ispitivane antibiotike, osim na vankomicin, što ide u prilog njihovoj identifikaciji kao bakterija Lactobacillus roda. Kao bitno funkcionalno svojstvo, u ovom radu, pokazano je da odabrani sojevi uspješno preživljavaju simulirane uvjete gastrointestinalnog trakta (GIT). Preživljavanje nepovoljnih uvjeta u GIT u visokom broju živih stanica omogućuje i kolonizaciju, za što je preduvjet adhezija na intestinalne epitelne stanice. Stoga je ispitana autoagregacija probiotičkih sojeva i koagregacija s različitim bakterijskim sojevima, te adhezija bakterijskih stanica na proteine ekstracelularnog matriksa domaćina: fibronektin, kolagen i laminin. Prema preliminarnim rezultatima ispitivani bakterijski sojevi imaju mogućnost adhezije na intestinalne epitelne stanice in vivo. Potrebno je provesti daljna istraživanja, no prema rezultatima ovog rada, navedeni sojevi se mogu primjeniti kao probiotički sojevi.

Abstract (english)

Particular Lactobacillus strains are being used as probiotics due to their health-promoting properties. In this study 11 different Lactobacillus strains have been selected and isolated from probiotic products. Reidentification of these strains was performed and the analysis of their functional properties was conducted in vitro. In order to distingush among probiotic strains, RAPD profiling method was performed, based on the PCR reaction conducted with specific Lactobacillus primers. The results of conventional microbiological methods, production of lactic acid, pH and API 50 CHL test confirmed these strains are lactic acid bacteria (LAB) representatives. According to the results of E-test, selected strains are sensitive to all antibiotics tested, with exception of vancomycin, what contributes to their identification as Lactobacillus strains. Important functional feature, survival of selected strains in simulated gastrointestinal tract (GIT) conditions was shown successful. Survival in simulated GIT conditions could promote strain colonization, whereas preliminar criteria for colonization is adhesion to intestinal epithelial cells. Therefore, autoaggregation of probiotic bacterial strains and coaggregation with different bacterial strains, as well as the adhesion of bacterial cells to proteins of extracellular matrix: fibronectin, collagen and laminin were examined. Tested bacterial strains showed capacity of adhesion to intestinal epithelial cells in vivo. Finally, further researches need to be performed for detailed characterization, but according to the results of this study, selected strains can be used as probiotic strains.

• Keywords: funkcionalnost; Lactobacillus; probiotici
• Keywords (english): functionality; Lactobacillus; probiotics
• Language: croatian
• URN:NBN: urn:nbn:hr:159:526524
• Study programme: Title: Molecular Biotechnology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka molekularne biotehnologije (magistar/magistra inženjer/inženjerka molekularne biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-02 12:23:53