Karakterizacija proteolitičke aktivnosti sojeva bakterija mliječne kiseline izoliranih iz majčinog mlijeka

undergraduate thesis

• Title (english): Characterization of proteolytic activity of lactic acid bacteria strains isolated from human breast milk
• Author: Dina El Khalifa
• Mentor: Katarina Butorac (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: 2023-07-14, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Bakterije mliječne kiseline (BMK) su skupina biotehnološko važnih mikroorganizama koji imaju sposobnost fermentacije šećera i proizvodnje proteolitičkih enzima. Proteolitički sustav Lactobacillus i Enterococcus sojeva omogućava hidrolizu kazeina prisutnog u fermentiranim mliječnim proizvodima do bioaktivnih peptida čime opskrbljuju stanicu aminokiselinama esencijalnim za rast te pridonose razvoju organoleptičkih svojstava mliječnih proizvoda. Cilj ovog rada bio je istražiti kazeinolitičko djelovanje BMK izoliranih iz majčinog mlijeka te odabrati soj s najboljom proteolitičkom aktivnošću. Analizom fenotipa hidrolize kazeina ustanovljeno je da sojevi L. plantarum MB18 i E. faecium AF16, prilikom inkubacije u obranom mlijeku, iskazuju značajno kazeinolitičko djelovanje. Ansonovom metodom, koja je provedena u svrhu kvantificiranja aktivnosti proteinaza, i analizom proteinskog profila razgradnje kazeina utvrđeno je da soj L. plantarum MB18 posjeduje najučinkovitije proteolitičko djelovanje, koji se može koristiti kao potencijalna starter kultura u svrhu proizvodnje funkcionalnih fermentiranih proizvoda.

Abstract (english)

Lactic acid bacteria (LAB) are a group of biotechnologically important microorganisms that have the ability to ferment sugars and produce proteolytic enzymes. The proteolytic system of Lactobacillus and Enterococcus strains enables the hydrolysis of casein in fermented dairy product into bioactive peptides, providing the cell with amino acids essential for growth and contributing to the development of the organoleptic properties of dairy products. The aim of this study was to investigate the caseinolytic activity of LAB, isolated from human breast milk, and to select a strain with the highest proteolytic activity. Phenotypic analysis of casein hydrolysis revealed that L. plantarum MB18 and E. faecium AF16 strains exhibited significant caseinolytic activity during incubation in skim milk. Using the Anson method performed to quantify protease activity and analysing the protein degradation profile of casein, it was found that L. plantarum MB18 possessed the most efficient proteolytic activity, making it a potential starter culture for the production of functional fermented products.

• Keywords: bakterije mliječne kiseline; proteinaze; Lactobacillus; kazein
• Keywords (english): lactic acid bacteria; proteases; Lactobacillus; casein
• Language: croatian
• URN:NBN: urn:nbn:hr:159:840889
• 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: 2024-05-06 09:05:24