Funkcionalna karakterizacija izolata bakterija mliječne kiseline za primjenu u inhibiciji Helicobacter pylori

undergraduate thesis

• Title (english): Functional characterization of lactic acid bacteria isolates for use in Helicobacter pylori inhibition
• Author: Helena Lalić
• Mentor: Deni Kostelac (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for General Microbiology and Food Microbiology); Zagreb
• Defense date and country: 2022-07-18, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Primjena probiotika u smanjenju tegoba uzrokovanih patogenom bakterijom Helicobacter pylori jedna je od istaknutijih potencijalnih alternativa antibiotičkoj terapiji. U ovom radu provedena je izolacija bakterija mliječne kiseline iz autohtonog ovčjeg sira te probiotička karakterizacija s ciljem pronalaska bakterijskih sojeva s potencijalom u inhibiciji H. pylori. Izolirano je deset sojeva te je određena antimikrobna aktivnost supernatanta kulture na rast H. pylori. Četiri izolata koja su pokazala stupanj inhibicije viši od 50 % dodatno su istraženi te su pokazali visok stupanj preživljenja u simuliranim uvjetima želuca. Izolati s najvećom sposobnosti autoagregacije biokemijski su identificirani kao Latilactobacillus curvatus DK1, Lacticaseibacillus paracasei DK5 i Latilactobacillus curvatus DK7. Daljnjim ispitivanjem antimikrobnog potencijala utvrđeno je kako sojevi Latilactobacillus curvatus DK1 i Lacticaseibacillus paracasei DK5 pokazuju značajan stupanj inhibicije H. pylori i nakon neutralizacije i termičke obrade supernatanta kulture što ukazuje na višestruke mehanizme ispoljavanja antimikrobne aktivnosti i izražen probiotički potencijal.

Abstract (english)

The use of probiotics to alleviate symptoms caused by the pathogenic bacterium Helicobacter pylori is one of the most prominent possible alternatives to antibiotic therapy. In this work, isolation of lactic acid bacteria from autochthonous sheep cheese and probiotic characterization were performed with the aim of finding bacterial strains that have the potential to inhibit H. pylori. Ten strains were isolated and the antimicrobial activity of the culture supernatant on H. pylori growth was determined. Four isolates that exhibited a degree of inhibition greater than 50% were further investigated and showed a high degree of survival under simulated gastric conditions. The isolates with higher autoaggregation ability were biochemically identified as Latilactobacillus curvatus DK1, Lacticaseibacillus paracasei DK5, and Latilactobacillus curvatus DK7. Further investigation of antimicrobial potential revealed that Latilactobacillus curvatus DK1 and Lacticaseibacillus paracasei DK5 strains exhibited a significant degree of inhibition of H. pylori even after neutralization and heat treatment of the culture supernatant, indicating multiple mechanisms of antimicrobial activity and distinct probiotic potential.

• Keywords: probiotici; Helicobacter; antimikrobna aktivnost; Latilactobacillus; Lacticaseibacillus
• Keywords (english): probiotics; Helicobacter; antimicrobial activity; Latilactobacillus; Lacticaseibacillus
• Language: croatian
• URN:NBN: urn:nbn:hr:159:162299
• Study programme: Title: Food Technology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka prehrambene tehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka prehrambene tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-10-20 09:48:50