Ispitivanje potencijalnog probiotičkog djelovanja bakterijskih sojeva Enterococcus faecium A7 i Lactobacillus fermentum A8

master's thesis

• Title (english): Investigation of potentional probiotic properties of bacterial strains Enterococcus faecium A7 and Lactobacillus fermentum A8
• Author: Đurđica Kujundžić
• Mentor: Jagoda Šušković (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: 2009-11, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Cilj ovog rada bio je ispitati potencijalno probiotičko djelovanje bakterijskih sojeva Enterococcus faecium A7 i Lactobacillus fermentum A8, izoliranih iz tradicionalnog svježeg sira. Ispitani bakterijski sojevi pokazuju dobru podnošljivost prema visokoj koncentraciji vodikovih iona (pH = 2,0) i djelovanju pepsina u simuliranom sekretu želuca. Neosjetljivi su prema djelovanju enzima gušterače i pokazuju otpornost prema djelovanju žučnih soli (3,0 mg/ml). Soj Enterococcus faecium A7 je osjetljiv na sve ispitane antibiotike, dok je Lactobacillus fermentum A8 rezistentan na vankomicin. Oba ispitana bakterijska soja pokazuju visok postotak autoagreagacije te mogućnost koagregacije s drugim bakterijama mliječne kiseline dok je soj Lactobacillus fermentum A8 koagregirao i s ispitanim test-mikroorganizmima. Bakterijski sojevi su preživjeli proces liofilizacije u visokom broju (cca 109 CFU/ml), a broj živih stanica liofiliziranih bakterijskih kultura ostao je nepromijenjen tijekom tri mjeseca čuvanja. Oba ispitana bakterijska soja pokazuju antimikrobno djelovanje prema test–mikroorganizmima soj Lactobacillus fermentum A8 pokazuje i dodatno, bakteriocinsko djelovanje prema srodnim bakterijskim vrstama.

Abstract (english)

The aim of this study was to investigate the potential probiotic properties of bacterial strains Enterococcus faecium A7 and Lactobacillus fermentum A8, isolated from traditional cottage cheese. Investigated bacterial strains have shown good tolerance to high concentration of hydrogen ions (pH = 2.0) and pepsin action in simulated stomach secrete. They were insensitive against the action of pancreatic enzymes and have shown resistance against the activity of bile acids (3.0 mg/ml). All tested antibiotics are inhibitory against Enterococcus faecium A7 strain, while Lactobacillus fermentum A8 strain have shown resistance to vancomycine. Both bacterial strains have shown good autoaggregation and coaggregation ability with different lactic acid bacteria, while Lactobacillus fermentum A8 strain have also shown ability to coaggregate with test-microorganisms. Tested bacterial strains have survived the freeze-drying process successfully (~109 CFU/ml) and the number of live cells stayed immutable during the three mounts of preservation. Both investigated bacterial strains have shown antimicrobial activity against different test-microorganisms and Lactobacillus fermentum A8 strain have shown additional bacteriocinogenic activity against similar bacterial species.

• Keywords: probiotici; simulirani uvjeti gastrointestinalnog trakta; agregacija; liofilizacija; antibakterijsko djelovanje
• Keywords (english): probiotic; simulated conditions of gastrointestinal tract; aggregation; lyophylization; antimicrobial properties
• Language: croatian
• URN:NBN: urn:nbn:hr:159:905751
• Study programme: Title: Biotechnology; specializations in: Biochemical Engineering; Course: Biochemical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo (diplomirani inženjer biotehnologije; smjer biokemijsko inženjerstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-09-01 08:49:06