Specifična svojstva Enterococcus faecium sojeva iz mikrobioma fermentirane hrane

undergraduate thesis

• Title (english): Specific properties of Enterococcus faecium strains from the microbiome of fermented foods
• Author: Ana Jakopić
• 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: 2022-07-18, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Mikrobiota fermentirane hrane, kao značajni dio bakterijske populacije, sadrži bakterije mliječne kiseline (BMK) iz roda Enterococcus koji se istražuju kao starter kulture. Prilikom selekcije funkcionalnih starter kultura iz roda Enterococcus izazov je razlikovati komensalne od oportunističkih sojeva. Upravo, cilj ovog rada je procijeniti sigurnost primjene Enteroccocus faecium sojeva za daljnja istraživanja primjene kao funkcionalnih starter kultura. Ustanovljeno je da analizirani E. faecium sojevi ne sintetiziraju enzim želatinazu i citolizin, te je ispitano svojstvo E. faecium sojeva da formiraju biofilm na abiotičkoj površini. Sposobnost formiranja biofilma na polistiren se razlikuje s obzirom na soj i ovisi o koncentraciji dostupnih nutrijenata. Analizirani E. faecium sojevi se mogu prirediti kao osušeni aktivni pripravci budući da su pokazali visok stupanj preživljavanja sušenja liofilizacijom. Sojevi E. faecium A7 i ZG 3-16 sadrže gen za enterocin A. E. faecium ZG 5-20 i ZG 7-10 sadrže i gen za enterocin B koji ima sinergističko djelovanje s enterocinom A, što proširuje spektar antimikrobnog djelovanja i potencijal primjene kao biokonzervansa. Iz rezultata proizlazi da se analizirani E. faecium sojevi mogu odabrati za daljnja istraživanja primijene kao funkcionalne starter kulture.

Abstract (english)

The microbiome of fermented foods is characterised by the high abundance of lactic acid bacteria (LAB) from the Enterococcus genus. During the screening of the Enterococcus as functional starter cultures, the challenge is to distinguish commensal from opportunistic strains. The aim of this work is to assess the safety of the use of Enterococcus strains from food microbiome for further research on their use as functional starter cultures. The analyzed strains of Enterococcus faecium do not synthesize gelatinase and cytolysin. The ability of E. faecium strains to form biofilm was also determined. The ability to form a biofilm varied depending on the tested strain and available nutrients. E. faecium strains can be prepared as freeze-dried preparations since they survived the lyophilisation at high bacterial counts. E. faecium A7 and ZG 3-16 strains contain the gene for enterocin A. E. faecium ZG 5-20 and ZG 7-10, in addition to entA also contains also entB which has a synergistic effect with enetrocin A which expands the spectrum of antimicrobial action and their importance as bioconservans. The obtained results suggest that the analysed E. faecium strains can be selected for further research on their application as functional starter cultures.

• Keywords: Enterococcus faecium; starter kulture; mikrobiota hrane; sigurnost primjene; biofilm
• Keywords (english): Enterococcus faecium; starter cultures; food microbiome; safety; biofilm
• Language: croatian
• URN:NBN: urn:nbn:hr:159:922268
• 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: Open access
• Created on: 2022-10-21 11:22:26