Ispitivanje antibakterijske aktivnosti odabranih probiotičkih bakterija i funkcionalnih starter kultura primjenom različitih mikrobioloških metoda

master's thesis

• Title (english): Testing the antimicrobial activity od selected probiotic bacteria and functional starter cultures by application of various microbiological methods
• Author: Silvija Šiftar
• Mentor: Blaženka Kos (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: 2014-11-06, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Tema ovoga rada je antimikrobno djelovanje funkcionalnih starter kultura Enterococcus faecium A7 i Lactobacillus fermentum A8, izoliranih iz hrvatskog tradicionalnog svježeg sira te komercijalnih probiotičkih bakterija, Lactobacillus reuteri RC-14 i Lactobacillus rhamnosus GR-1. Primjenom metode difuzije u agar je ispitano antibakterijsko djelovanje prema test-mikroorganizama Escherichia coli 3014 i Salmonella enterica serovar Typhimurium FP1. Sva četiri soja su jače inhibirala rast test-mikroorganizma Salmonella Typhimurium FP1 pri čemu je soj Lactobacillus reuteri RC-14 bio nešto uspješniji u inhibiciji oba test-mikoorganizma u odnosu na druge sojeve. Ispitana je i potencijalna bakteriocinska aktivnost autohtonih sojeva prema srodnim bakterijskim vrstama metodom s dvostrukim slojem agara. Bakterijski sojevi su inhibirali rast oba test-mikroorganizma te bakterija mliječne kiseline Lactobacillus rhamnosus GG, Enterococcus faecuim ATCC 9430 i Lactococcus lactis subsp. lactis LMG 9450. Turbidimetrijskom metodom je dodatno potvrđeno inhibicijsko djelovanje prema navedenim sojevima pri čemu je dokazano da je inhibicijski učinak supernatanata kultura toliko učinkovit da se može primijeniti i u razrijeđenom obliku, odnosno u matriksu gdje je potrebno antimikrobno djelovanje ispitivanog bakterijskog soja.

Abstract (english)

The subject of this work is antimicrobial activity of the functional starter cultures Enterococcus faecium A7 and Lactobacillus fermentum A8, isolated from Croatian traditional fresh cheese, and of commercial probiotic bacteria, Lactobacillus reuteri RC-14 and Lactobacillus rhamnosus GR-1. Antibacterial activity against test-microorganisms Escherichia coli 3014 and Salmonella enterica serovar Typhimurium FP1 has been tested using agar diffusion method. All four strains have strongly inhibited the growth of the test-microorganism Salmonella Typhimurium FP1 wherein the strain Lactobacillus reuteri RC-14 was slightly more effective in inhibiting both test-microorganism, as compared to other strains. Moreover, potential bacteriocinogenic activity of autochthonous strains against related bacterial species has been examined by agar-spot-test method. Bacterial strains inhibited the growth of both test-microorganisms and lactic acid bacteria Lactobacillus rhamnosus GG, Enterococcus faecuim ATCC 9430 and Lactococcus lactis subsp. lactis LMG 9450. Inhibitory activity against these strains has been further confirmed by using turbidimetric method, wherein the inhibitory effect of cultures supernatants was so effective that it could be applied in diluted form, or in the matrix, where appropriate antimicrobial activity of tested bacterial strain is needed.

• Keywords: antimikrobna aktivnost; bakteriocini; bakterije mliječne kiseline; probiotici; starter kulture
• Keywords (english): antimicrobial activity; bacteriocins; lactic acid bacteria; probiotics; starter cultures
• Language: croatian
• URN:NBN: urn:nbn:hr:159:237973
• 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: 2017-04-26 12:44:23