In vitro evaluacija otpornosti probiotičkih sojeva na uvjete gastrointestinalnog trakta

undergraduate thesis

• Title (english): In vitro evaluation of the tolerance of the probiotic strains on the conditions of the gastrointestinal tract
• Author: Ana Filipović
• 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: 2015-06-16, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Cilj ovog rada je ispitati otpornost probiotičkih sojeva iz roda Lactobacillus i Bifidobacterium, izoliranih iz liofiliziranih probiotičkih pripravaka, na in vitro uvjete gastrointestinalnog trakta (GIT). Ispitano je preživljavanje bakterijskih sojeva u simuliranom želučanom soku i simuliranom soku tankog crijeva, a zatim tolerancija na 0.3% i 0.6% žučni soli, te in vitro adhezija na glikoprotein mucin, što može doprinjeti iskazivanju funkcionalnih učinaka u domaćinu. Smrtnost probiotičkih sojeva tijekom 6 sati izlaganja bakterijskih stanica simuliranim uvjetima GIT je bila u rasponu vrijednosti od 0.94-3.16 logCFU/ml, što ukazuje na uspješno preživljavanje ispitivanih sojeva u simuliranim uvjetima GIT. Prema rezultatima, ispitane probiotičke bakterije, s obzirom na soj, su različito otporne na testirane koncentracije žučnih soli. Nakon uzgoja u MRS tekućoj podlozi, pokazalo se da pojedini sojevi, primjerice Lactobacillus reuteri DSM 17938, iskazuju mogućnost vezanja na mucin. Na temelju provedenih eksperimenata može se zaključiti da ispitane probiotičke bakterije uspješno preživljavaju nepovoljne uvjete GIT-a domaćina, što je jedan od glavnih kriterija za izbor probiotika u svrhu prirodnog uspostavljanja i održavanja ravnoteže crijevne mikrobiote.

Abstract (english)

The purpose of this research is to examine the tolerance of probiotics strains from Lactobacillus and Bifidobacterium genus, isolated from commercial freeze dried probiotic preparations, to in vitro conditions of the gastrointestinal tract (GIT). We observed the survival of bacterial strains in simulated gastric and simulated small intestine juice. In addition, we examined their tolerance to 0.3% and 0.6% bile salts and in vitro adhesion to glycoprotein mucin, the characteristics which can contribute to expression of functional effects in a host. The mortality of probiotic strains during six hours of exposure of the bacterial cells to simulated conditions of the GIT was in the range 0.94-3.16 logCFU/ml, which indicates successful survival of tested strains in simulated conditions of the GIT. According to results, the examined probiotic bacteria tolerated tested bile salt concentrations. After cultivation on MRS broth medium, it was found that certain strains, e.g. Lactobacillus reuteri DSM 17938 show a possibility of adhesion to mucin. Based on conducted research, we can conclude that tested probiotic bacteria successfully survive in inimical conditions in the GIT of a host, which is one of the main criteria for selection of probiotics with a purpose of building and maintaining natural balance of intestinal microbiota.

• Keywords: Bifidobacterium; Lactobacillus; probiotici; uvjeti gastrointestinalnog trakta
• Keywords (english): Bifidobacterium; Lactobacillus; probiotics; gastrointestinal tract conditions
• Language: croatian
• URN:NBN: urn:nbn:hr:159:475242
• Study programme: Title: Biotechnology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka biotehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-03 10:30:37