Egzopolisaharidi kao funkcionalne biomolekule probiotičkih bakterija

undergraduate thesis

• Title (english): Exopolysaccharides as functional biomolecules of the probiotic bacteria
• Author: Darija Begić
• 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: 2020-09-15, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Bakterije mliječne kiseline (BMK) sintetiziraju spektar polisaharida koji se odlikuju raznolikošću u strukturi, sastavu gradivnih podjedinica i mehanizmom biosinteze. Zbog svojih fizikalno-kemijskih svojstava ovi polimeri se industrijski primjenjuju za poboljšanje teksture i senzorskih svojstava fermentiranih proizvoda. No osim doprinosa tehnološkim aspektima, egzopolisharidi BMK imaju funkciju zaštitnog sloja koji određuje i karakteristike površine bakterijske stanice, a značajni su za preživljavanje probiotičkih sojeva prilikom prolaska kroz gastrointestinalni trakt (GIT) domaćina. Pretpostavlja se da ove površinske biomolekule posreduju prilikom interakcija bakterijske stanice s mikrookolišem, a istražuje se potencijalna biološka uloga u imunomodulaciji, antioksidativnom, antimikrobnom, čak antitumorskom djelovanju probiotičkih bakterija. Zbog specifične kemijske strukture ne razgrađuju se u GIT, te u kolonu domaćina mogu biti izvor supstrata za korisne bakterijske vrste iz roda Bifidobacterium gdje selektivno potiču njihov rast i tako posreduju u modulaciji sastava intestinalne mikrobiote. U kolonu mogu biti izvor ugljika i za druge predstavnike intestinalne mikrobiote koji ih fermentiraju do kratkolančanih masnih kiselina (engl. short-chain fatty acids; SCFA) poput butirata, propionata i acetata koje su značajne u snabdjevanju energije stanica intestinalnog epitela, modulaciji metaboličkih puteva, inhibiciji intestinalnih patogena i imunomodulaciji.

Abstract (english)

Lactic acid bacteria (LAB) synthesize a spectrum of polysaccharides characterized by diversity in structure, the composition of repeating units and mechanism of biosynthesis. Due to their physical-chemical properties, these polymers have an industrial application to improve the texture and sensory properties of fermented products. In addition to contributing to technological aspects, LAB exopolysaccharides have the function of a protective layer that determines the characteristics of the bacterial cell surface and promote the survival of probiotic strains in the gastrointestinal tract (GIT) of the host. These surface biomolecules mediate bacterial cell-microenvironment interactions. Their potential roles in immune response, antioxidant, antimicrobial, and even antitumor activities of probiotic bacteria are investigated. Due to their specific chemical structure, exopolysaccharides are not digested in the upper GIT, and in the colon can be a source of substrates for beneficial Bifidobacterium strains and also can be utilized by other specific beneficial members of the gut microbiota with the influence on intestinal microbiota composition. In colon some representatives of the intestinal microbiota ferment them to short-chain fatty acids (SCFA) such as butyrate, propionate and acetate, which are important in supplying energy to intestinal epithelial cells, modulating metabolic pathways, inhibition of intestinal pathogens and immune response.

• Keywords: bakterije mliječne kiseline; funkcionalne biomolekule; egzopolisaharidi; probiotici
• Keywords (english): exopolysaccharides; functional biomolecules; lactic acid bacteria; probiotic
• Language: croatian
• URN:NBN: urn:nbn:hr:159:532347
• 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: 2020-10-22 12:50:29