Kompetitivna ekskluzija patogena sojem producentom egzopolisaharida Limosilactobacillus fermentum MC1

master's thesis

• Title (english): Competitive exclusion of pathogens by the exopolysaccharide-producing Limosilactobacillus fermentum MC1 strain
• Author: Petra Knez
• Mentor: Andreja Leboš Pavunc (mentor)
• Committee member: Jasna Novak (predsjednik povjerenstva)
• Committee member: Ksenija Durgo (član povjerenstva)
• Committee member: Marina Cvjetko Bubalo (član povjerenstva)
• 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: 2023-07-06, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Cilj ovog rada bio je ispitati kompetitivnu ekskluziju test-mikroorganizma Escherichia coli 3014 probiotičkim sojem Limosilactobacillus fermentum MC1, producentom egzoplisaharida (EPS), korištenjem Caco-2 stanične linije u in vitro uvjetima. Također je ispitan utjecaj različitih koncentracija sintetitziranih EPS-a na kompetitivnu ekskluziju. Proučavan je i utjecaj mikroinkapsulacije soja MC1 u alginatu, uz dodatak fruktooligosaharida ili galaktooligosaharida, na preživljavanje stanica soja MC1 u procesu liofilizacije, izlaganja simuliranim uvjetima gastrointestinalnog trakta te skladištenja. Rezultati su pokazali da EPS kojeg sintetizira L. fermentum MC1 smanjuje adhezivna svojstva E. coli, s time da veća koncentracija podrazumijeva i snažnije djelovanje. Najveća antiadhezivna svojstva pokazao je uzorak koji je sadržavao 1 mg mL-1 EPS-a. Mikroinkapsulacija u natrijevom alginatu pokazala se kao dobra tehnika za zaštitu MC1 soja. Dodatak oligosaharida soju MC1 osigurava bolje preživljavanje liofilizacije te simuliranih uvjeta gastrointestinalnog trakta i tijekom skladištenja, s tim da su se galaktooligosaharidi u gotovo svim segmentima istraživanja pokazali kao bolji izbor prebiotika nego fruktooligosaharidi.

Abstract (english)

The aim of this work was to examine the competitive exclusion of the test microorganism Escherichia coli 3014 by the probiotic strain Limosilactobacillus fermentum MC1, an exopolysaccharide (EPS) producer, using the Caco-2 cell line in vitro. The influence of different concentrations of synthesized EPSs on competitive exclusion was also examined. The effect of microencapsulation of MC1 strain in alginate, with the addition of fructooligosaccharides or galactooligosaccharides, on the survival of MC1 cells during the lyophilization process, simulated gastrointestinal tract (GIT) conditions and storage was also studied. The results showed that EPSs synthesized by L. fermentum MC1 reduce the adhesive properties of E. coli, with a higher concentration implying a stronger effect. The sample containing 1 mg mL-1 EPS showed the highest anti-adhesive properties. Microencapsulation in sodium alginate proved to be a good technique for the protection of the MC1 strain. The addition of oligosaccharides to MC1strain ensures better survival of lyophilization and simulated GIT conditions and storage, with the fact that galactooligosaccharides proved to be a better choice of prebiotics than fructooligosaccharides in almost all segments of the research.

• Keywords: probiotičke bakterije; egzopolisaharidi; adhezijska svojstva; mikroinkapsulacija; oligosaharidi
• Keywords (english): probiotic bacteria; exopolysaccharides; adhesion properties; microencapsulation; oligosaccharides
• Language: croatian
• URN:NBN: urn:nbn:hr:159:785892
• 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: Open access
• Created on: 2024-04-29 11:15:50