Utjecaj visoke temperature i proteinaze K na antibakterijsku aktivnost Lactobacillus sojeva

master's thesis

• Title (english): Effects of high temperature and proteinase K on antibacterial activity of Lactobacillus strains
• Author: Lucija Vučko
• Mentor: Blaženka Kos (mentor)
• Committee member: Jagoda Šušković (predsjednik povjerenstva)
• 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: 2020-07-01, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Cilj diplomskog rada bio je ispitati utjecaj visoke temperature i proteinaze K na antibakterijsku aktivnost, kao i ekspresiju S-proteina autohtonih sojeva Lactobacillus plantarum SF9C i Lactobacillus brevis SF9B. Na temelju provedenih metoda za određivanje antimikrobne aktivnosti, oba ispitivana Lactobacillus soja pokazala su srednje do jako antibakterijsko djelovanje prema odabranim testmikroorganizmima, potencijalnim onečišćivačima hrane. Međutim, dobiveni rezultati nakon izlaganja supernatanta kulture soja Lb. plantarum SF9C visokoj temperaturi i enzimu proteinaza K pokazuju kako djelovanjem visoke temperature i proteinaze K dolazi do smanjenja antibakterijske aktivnosti prema ispitivanim test-mikroorganizmima, što je uzrokovano inaktivacijom proizvedenog bakteriocina plantaricina. Nadalje, potvrđena je ekspresija S-proteina kod soja Lb. brevis SF9B te odsutnost Sproteina kod soja Lb. plantarum SF9C. Na temelju dobivenih rezultata može se zaključiti kako bi svojstvo proizvodnje bakteriocina soja Lb. plantarum SF9C i S-proteina soja Lb. brevis SF9B moglo omogućiti njihovu potencijalnu združenu primjenu kao probiotičkih sojeva s pojačanim probiotičkim učinkom njihovih specifičnih biomolekula.

Abstract (english)

The aim of the master thesis was to examine the effects of high temperature and proteinase K on the antibacterial activity as well as the S-layer protein expression of the Lactobacillus plantarum SF9C and Lactobacillus brevis SF9B strains. Based on the conducted methods for the determination of antimicrobial activity, both tested Lactobacillus strains showed moderate to strong antibacterial activity against selected test-microorganisms, potential food contaminants. However, the results obtained after exposure of the culture supernatant of strain Lb. plantarum SF9C to high temperature and the enzyme proteinase K showed that it caused a decrease in its antibacterial activity against the testmicroorganisms, which was caused by an inactivation of the produced bacteriocin plantaricin. Furthermore, S-protein expression was confirmed in Lb. brevis SF9B strain, as well as the absence in Lb. plantarum SF9C strain. Based on the obtained results, it can be concluded that the ability of bacteriocin production of strain Lb. plantarum SF9C and the S-layer protein expression of strain Lb. brevis SF9B could enable their potential combined use as probiotic strains with enhanced probiotic effect of their specific biomolecules.

• Keywords: antimikrobno djelovanje; bakterije mliječne kiseline; bakteriocini; S-proteini
• Keywords (english): antimicrobial activity; lactic acid bacteria; bacteriocins; S-layer proteins
• Language: croatian
• URN:NBN: urn:nbn:hr:159:133095
• 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: Open access
• Created on: 2020-07-03 09:18:24