Usporedba probiotičkih svojstava Enterococcus i Lactococcus vrsta bakterija mliječne kiseline

master's thesis

• Title (english): Probiotic propertis comparison of Enterococcus and Lactococcus species of lactic acid bacteria
• Author: Kristina Kanižaj
• 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: 2012-07-16, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Asimilacija kolesterola i prebiotičkih supstrata fukcionalna su svojstva probiotičkih sojeva koja dodatno mogu doprinijeti njihovim poželjnim učincima na zdravlje domaćina. Odabrani sojevi Lactococcus i Enterococcus vrsta zadovoljili su opće kriterije za izbor probiotičkih sojeva. Kako bi se isključila mogućnost širenja antibiotičke rezistencije, ispitivana je osjetljivost odabranih sojeva bakterija mliječne kiseline (BMK) na 5 antibiotika. Ispitivanjem je pokazano da je soj Enterococcus faecium ZG1-54 osjetljiv na svih šest ispitivanih antibiotika, dok su sojevi Lactococcus lactis BGAL1-1 i Lactococcus lactis subsp. lactis BGLE1-6 pokazali rezistenciju na eritromicin, a soj Lactococcus lactis ZG5-9 na tetraciklin i vankomicin. U svrhu postizanja pojačanog, sinbiotičkog učinka, ispitivana je asimilacija prebiotičkih supstrata (manitola, laktuloze, raftiloze i inulina) s odabranim probiotičkim sojevima BGAL1-1, BGLE1-6, ZG1-54 i ZG5-9. Njihov rast, promjena pH i sinteza mliječne kiseline najveći su prilikom uzgoja u hranjivim podlogama s manitolom i laktulozom kao prebiotičkim supstratima. Za određivanje bazičnih i kiselih svojstava mikrobnih stanica korištena je metoda mikrobne adhezije u 3 otapala. Velik postotak adhezije stanica BGAL1-1 na heksan upućuje na njihovu hidrofobnost, a rezultati ispitivanja mikrobne adhezije na kloroform pokazuju afinitet ispitivanih BMK za to kiselo otapalo, što upućuje na njihova elektrondonorska svojstva. Izabrani probiotički sojevi ne pokazuju antagonizam jedni prema drugima te mogu rasti kao združena kultura u istoj hranjivoj podlozi. Odabrani sojevi imaju sposobnost asimilacije kolesterola, što bi moglo biti još jedno poželjno svojstvo probiotičkih bakterija.

Abstract (english)

Assimilation of cholesterol and prebiotic substrates are functionally properties of prebiotics strains that can further contribute to their desirable effects on the health of the host. Selected strains of Lactococcus and Enterococcus species satisfied the general criteria for the selection of probiotics strains. In order to exclude the possibility of spread of antibiotic resistance, we examined the sensitivity of lactic acid bacteria (LAB) to 5 antibiotics. The investigation shown that the strain Enterococcus faecium ZG1-54 was sensitive to all six tested antibiotics, while strains Lactococcus lactis BGAL1-1 and Lactococcus lactis subsp. lactis BGLE1-6 showed resistance to erythromycin and a strain Lactococcus lactis ZG5-9 to tetracycline and vancomycin. In order to achieve stronger synbiotic effect, we have studied the assimilation of prebiotic substrates (mannitol, lactulose, inulin and raftiloze) with selected probiotic strains BGAL1-1, BGLE1-6, ZG1-54 and ZG5-9. Growth of selected strains, the changes of pH and synthesis of lactic acid were the highest during cultivation in nutrient media with mannitol and lactulose as a prebiotic substrates. For the determination of basic and acidic properties of microbial cells has been used method of microbial adhesion in 3 solvents. A large percentage adhesion of cell BGAL1-1 to hexane indicate to their hydrophobicity and the results of microbial adhesion to chloroform show an affinity of the investigated BMK to acidic solvent. It refers to their electron-donor properties. Selected probiotic strains did not show antagonism towards each other and can grow as paired in the same culture medium. Selected strains have the ability to assimilate cholosterol, which could be another desirable characteristic of probiotic bacteria.

• Keywords: bakterije mliječne kiseline; Lactococcus; Enterococcus; prebiotički supstrati; kolesterol; stresni uvjeti
• Keywords (english): lactic acid bacteria; Lactococcus; Enterococcus; prebiotic supstrates; cholesterol; stress conditions
• Language: croatian
• URN:NBN: urn:nbn:hr:159:316737
• 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: 2017-05-09 11:10:51