Biotehnološka proizvodnja probiotičkih bakterija: Enterococcus faecium L3 i Enterococcus faecium A7

master's thesis

• Title (english): Biotechnological production of probiotic bacteria: Enterococcus faecium L3 and Enterococcus faecium A7
• Author: Ivica Miše
• Mentor: Jasna Beganović (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: 2010-10, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Glavni zahtjev pri izboru probiotičkih sojeva je njihovo preživljavanje u gastrointestinalnom traktu, a za postizanje probiotičkog učinka pripravci moraju sadržavati žive mikrobne stanice u koncentracijama višim od 106 po gramu proizvoda. Zbog toga se istražuju različite metode koje mogu doprinijeti povećanju njihovog preživljavanja tijekom biotehnološke proizvodnje, čuvanja ili primjene probiotika u različitim proizvodima, te nakon oralne primjene u gastrointestinalnom traktu domaćina. Cilj ovog rada je bio ispitati preživljavanje probiotičkih bakterija Enterococcus faecium L3 i Enterococcus faecium A7 tijekom liofilizacije, uz dodatak različitih lioprotektora. Najveći broj živih probiotičkih stanica E. faecium L3 postignut je u liofiliziranom pripravku u kojima je kao lioprotektor dodana laktoza, a kod E. faecium A7 je najveći postotak postignut uz dodatak obranog mlijeka u prahu. Prisutnost čistih kultura E. faecium L3, odnosno E. faecium A7 u suhom aktivnom pripravku dobivenom liofilizacijom dokazana je RAPD metodom. Također je ispitana učinkovitost mikroinkapsulacije provedene, s različitim nosačima, te njezin utjecaj na funkcionalnost navedenih probiotičkih bakterija. Mikroinkapsulacija stanica probiotičkih bakterija, provedena s alginatom kao nosačem, je pokazala najbolji zaštitni učinak tijekom izlaganja probiotičkih stanica simuliranim gastrointestinalnim uvjetima. Probiotičke bakterije, E. faecium L3 i E. faecium A7, pokazale su i snažno antimikrobno djelovanje prema odabranim test mikroorganizmima (Staphylococcus aureus 3048, Staphylococcus aureus K-144, Escherichia coli 3014, Salmonella enterica serovar Typhimurium FP1, Bacillus subtilis ATCC 6633 i Bacillus cereus TM2) što im omogućuje kompetitivnu ekskluziju nepoželjnih mikroorganizama, kad dospiju u intestinalni trakt, gdje se očekuje njihova probiotička aktivnost.

Abstract (english)

The major criterion for the selection of probiotics is their survival during the transit through gastrointestinal tract and in order to express their health benefits, the probiotic preparations need to contain at least 106 viable cells per gram of the product. Therefore, several different methods have been investigated with the aim to improve the viability of probiotics during their biotechnological production, storage or application in different food products and after an oral application in the host gastrointestinal conditions. The objective of this study was to investigate the effects of different lyoprotectants on the survival of probiotic strains Enterococcus faecium L3 and Enterococcus faecium A7 during freeze-drying. The highest number of viable E. faecium L3 cells was reached in the freeze-dried product where lactose was used as lyoprotectants, and in the case of the E. faecium A7 cells, the highest percentage of survival was obtained with skim milk. The presence of pure culture E. faecium L3 or E. faecium A7 in freeze-dried preparations was confirmed by RAPD method. Efficiency of microencapsilation, performed in different carriers, and its impact on the functionality of the probiotic strains was also investigated. Microencapsulation in alginate has shown the greatest protective role during exposure of the microencapsulated probiotic strains was to the simulated gastrointestinal tract. Probiotic strains E. faecium L3 and E. faecium A7 have also shown a strong antimicrobial activity against selected test microorganisms (Staphylococcus aureus 3048, Staphylococcus aureus K-144, Escherichia coli 3014, Salmonella enterica serovar Typhimurium FP1, Bacillus subtilis ATCC 6633 and Bacillus cereus TM2) what is an important prerequisite for competitive exclusion of undesirable bacteria in intestinal tract, where their probiotic activity is expected.

• Keywords: probiotici; Enterococcus faecium; liofilizacija; mikroinkapsulacija; simulirani uvjeti gasteointestinalnog trakta
• Keywords (english): probiotics; Enterococcus faecium; freeze-drying; microencapsulation; simulated gastrointestinal tract
• Language: croatian
• URN:NBN: urn:nbn:hr:159:499381
• Study programme: Title: Biotechnology; specializations in: Biochemical-Microbiology; Course: Biochemical-Microbiology; Study programme type: university; Study level: graduate; Academic / professional title: diplomirani inženjer biotehnologije; smjer biokemijsko-mikrobiološki (diplomirani inženjer biotehnologije; smjer biokemijsko-mikrobiološki)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-08-28 09:24:15