Mikrostrukturna, biokemijska i antimikrobna karakterizacija bakterijske celuloze uzgojene u čaju crvenog grma

undergraduate thesis

• Title (english): Microstructural, biochemical and antimicrobial characterization of bacterial cellulose obtained by rooibos tea fermentation
• Author: Ivana Hranić
• Mentor: Sunčica Beluhan (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Biochemical Engineering); (Laboratory for Biochemical Engineering, Industrial Microbiology and Malting and Brewing Technology); Zagreb
• Defense date and country: 2017-07-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Kombucha je tradicionalno osvježavajuće piće dobiveno fermentacijom zaslađenog čaja sa simbiotskim kulturama octenih bakterija i kvasaca. U ovom je radu proučavana proizvodnja organskih kiselina (octene i glukonske), etanola i bakterijske celuloze biotransformacijomkombuche u zaslađenom (60, 80 i 100 g/L) Rooibos čaju. Promjene pH vrijednosti su povezane sa simbiotskim metaboličkim aktivnostima kvasaca i bakterija octene kiseline, pri čemu se pH vrijednostsmanjivala s porastom proizvodnje octene kiseline. Analiziranjem uzoraka FT-IR spektroskopijom, XDR analizom i skenirajućom elektronskom mikroskopijom, određeno je da uzorak sadrži viši postotak amorfnih regije nego kristalnih regija, kao što je i očekivano. Debljina sloja i prinos bakterijske celuloze je rastao tijekom vremena fermentacije. Antimikrobna svojstva su opažena na testnim mikroorganizmima (Salmonellatyphimurium, Escherichiacoli iPseudomonassp.), dok Vibriocholerae nije bio inhibiran uzorcima kombuche. Rezultati ovog istraživanja upućuju na to da prinos celuloze ovisi o mnogo čimbenika koje trebaju optimizirati kako bi se postigao maksimalni prinos.

Abstract (english)

Kombuchais a traditional refreshing beverage obtained by the fermentation of sweetened tea with a powerful symbiosis of acetic bacteria and yeasts. In this work, the production of organic acids (acetic and gluconic), ethanol and bacterial cellulose by biotransformation of kombucha in Rooibos tea sweetened with sucrose (60, 80 and 100 g/L) was studied. Changes in pH were related to the symbiotic metabolic activities of yeasts and acetic acid bacteria, and it is decreased by the formation of organic acids. Analysing samples by FT-IR spectroscopy, XRD analysis and scanning electron microscopy, it was detected that the sample had higher percentage of amorphous regions, than crystalline regions, as it was expected. The thickness and yield of bacterial cellulose increased with fermentation time. Antimicrobial activities was observed in the fermented samples against the tested microorganisms (Salmonella typhimurium, Escherichia coli and Pseudomonas sp.), but Vibrio cholearaewas not inhibited by kombucha.Findings from this study suggest that the yield of cellulose depends on many factors that need to be optimized to achieve maximum yield.

• Keywords: kombucha; bakterijske celuloza; morfologija; fizikalna svojstva; antimikrobna svojstva
• Keywords (english): kombucha; bacterialcellulose; morphology; physicalproperties; antimicrobialproperties
• Language: croatian
• URN:NBN: urn:nbn:hr:159:298855
• 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: 2017-07-18 09:27:29