Strukturna karakterizacija egzopolisaharida proizvedenih pomoću Lactobacillus fermentum D12

master's thesis

• Title (english): Structural characterization of exopolysaccharides produced BY Lactobacillus fermentum D12
• Author: Tina Vidulin
• 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: 2018-07-19, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Egzopolisaharide (EPOL-e), biopolimere široko rasprostranjene u prirodi, bakterije izlučuju u ekstracelularni matriks. Klasificiraju se u dvije glavne skupine: homoegzopolisaharidi (homo-EPOL-i), sastavljeni od jedne vrste monosaharida i heteroegzopolisaharidi (hetero-EPOL-i), sastavljeni od različitih vrsta monosaharida. Cilj ovog rada bio je sinteza EPOL-a pomoću bakterije mliječne kiseline Lactobacillus fermentum D12, ispitivanje utjecaja sastava podloge na sintezu EPOL-a te njihova strukturna analiza. Smjesa izoliranih egzopolisaharida uspješno je razdvojena u tri frakcije kromatografijom visoke djelotvornosti isključenjem na osnovi veličine čestica, a instrumentalne analize sastava i analize glikozidnih veza provedene su na samoj smjesi kao i na svim dobivenim frakcijama. Rezultati analiza pokazali su kako uzorak Lactobac 1 uglavnom sadrži α-glukan koji se sastoji od 1,4- vezane α-D-glukoze, gdje je 20% šećera acetilirano na C-3 položaju. Analiza sastava uzoraka Lactobac 2 i Lactobac 3 pokazala je da se polisaharidi prisutni u uzorcima sastoje od manoze, glukoze i galaktoze u različitim omjerima, dok je analiza glikozidnih veza ukazala na prisutnost nekoliko točaka grananja u strukturi polisaharida.

Abstract (english)

Exopolysaccharides (EPOLs), biopolymers widespread in nature, are extracted by bacteria in the extracellular matrix. They are classified into two main groups: homoexopolysaccharides (homo-EPOL), consisted of one type of monosaccharides, and heteroexopolysaccharides (hetero-EPOL) consisted of different types of monosaccharides. The main goal of this thesis was to synthesize EPOLs with lactic acid bacteria Lactobacillus fermentum D12, to investigate the effect of media composition on EPOLs synthesis and structural characterization of produced EPOLs. Mixture of isolated EPOLs was successfully separated in three fractions by high performance size exclusion chromatography and composition analysis together with linkage analysis was performed both on mixture and on obtained fractions. Results of the analysis showed that sample Lactobac 1 mainly contains an α-glucan consisted of 4-linked α-D-glucose, where 20 % of sugars bear an acetyl substituent on the C-3 position. Furthermore, composition analysis of samples Lactobac 2 and Lactobac 3 showed that present polysaccharides are consisted of mannose, glucose, galactose in different ratios, while glycoside linkage analysis indicates the presence of few branching points in EPOLs.

• Keywords: Lactobacillus fermentum; egzopolisaharidi
• Keywords (english): Lactobacillus fermentum; exopolysaccharides
• Language: croatian
• URN:NBN: urn:nbn:hr:159:039334
• 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: 2019-11-27 10:26:38