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Title:Sestava in viskoelastične lastnosti zunajceličnih polisaharidov pri izbranih sevih ocetnokislinskih bakterij
Authors:ID Jančič, Nina (Author)
ID Trček, Janja (Mentor) More about this mentor... New window
ID Škraban, Jure (Comentor)
Files:.pdf MAG_Jancic_Nina_2019.pdf (1,46 MB)
MD5: FE4AB72D78B803499331DD139E3C814F
PID: 20.500.12556/dkum/be2e4224-2d39-4366-9da3-a960ef44a518
 
Language:Slovenian
Work type:Master's thesis/paper
Typology:2.09 - Master's Thesis
Organization:FNM - Faculty of Natural Sciences and Mathematics
Abstract:V magistrski nalogi smo pri 23 izbranih sevih ocetnokislinskih bakterij iz rodov Komagataeibacter, Acetobacter, Asaia, Gluconobacter in Swaminathania preučevali sposobnost za tvorbo zunajceličnih polisaharidov ter nadalje analizirali njihovo monosaharidno sestavo. Seve smo pridobili iz zbirke mikroorganizmov Fakultete za naravoslovje in matematiko Univerze v Mariboru. Sposobnost za tvorbo zunajceličnih polisaharidov smo ocenili iz potencialno nastalega biofilma. Med 23 sevi smo tako identificirali 18 sevov s sposobnostjo za tvorbo biofilma pri uporabljenih pogojih namnoževanja. Nato smo s pomnoževanjem specifičnih odsekov genov za sintezo celuloze, acetana in levana v reakciji PCR analizirali prisotnost genov za sintezo najpogosteje opisanih zunajceličnih polisaharidov pri ocetnokislinskih bakterijah. Pri 18 sevih smo identificirali prisotnost gena za sintezo celuloze, devet sevov pa je imelo tudi gene za tvorbo levana in/ali acetana. Acetan je heteropolisaharid, sestavljen iz glukoze, manoze, ramnoze in glukuronske kisline, v njegovo sintezo pa je vključenih veliko število genov. Prisotnost oz. odsotnost določenih genov tako lahko povzroči sintezo različnih acetanov, zaradi česar imajo sevi z geni za izražanje acetanov največji potencial za sintezo novih zunajceličnih polisaharidov. Iz 10 sevov smo uspešno izolirali in očistili vodotopne zunajcelične polisaharide ter jih s postopkom hidrolize razgradili na monosaharide. Identiteto monosaharidov smo določili s tankoplastno kromatografijo ob uporabi sladkornih standardov. Na podlagi vseh teh rezultatov smo izbrali tri seve, za katere domnevamo, da so dobri kandidati za tvorbo novih acetanu podobnih polisaharidov. Analiza njihovih reoloških lastnosti je odkrila razlike v njihovih viskoelastičnih lastnostih. Za natančen opis fizikalnih in kemijskih lastnosti teh polisaharidov so potrebne nadaljnje analize.
Keywords:Ocetnokislinske bakterije, biofilm, zunajcelični polisaharidi.
Place of publishing:Maribor
Publisher:[N. Jančič]
Year of publishing:2019
PID:20.500.12556/DKUM-73418 New window
UDC:579.26:577.15:615.28(043.2)
COBISS.SI-ID:24589832 New window
NUK URN:URN:SI:UM:DK:IHGXKGEF
Publication date in DKUM:11.06.2019
Views:2436
Downloads:146
Metadata:XML DC-XML DC-RDF
Categories:FNM
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Licences

License:CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:11.04.2019

Secondary language

Language:English
Title:Composition and viscoelastic properties of extracellular polysaccharides in selected strains of acetic acid bacteria
Abstract:The objective of this master thesis was to screen among 23 selected strains of acetic acid bacteria from the genera Komagataeibacter, Acetobacter, Asaia, Gluconobacter and Swaminathania for their ability to form extracellular polysaccharides, and further on to analyse their monosaccharide composition. We acquired the strains from the collection of microorganisms from the Faculty of Natural Sciences and Mathematics of the University of Maribor. The ability to form extracellular polysaccharides was evaluated from the formation of biofilm. Among the 23 strains, we identified 18 strains with the ability to form a biofilm under the applied growth conditions. Subsequently, the PCR amplification of specific genes for the synthesis of cellulose, acetane and levane enabled us to analyse the presence of genes for the synthesis of most commonly described extracellular polysaccharides among acetic acid bacteria. Among the 18 strains, the presence of gene for cellulose synthesis was determined, and nine strains additionally contained genes for the synthesis of levan and/or acetan. Acetan is a heteropolysaccharide composed of glucose, mannose, rhamnose, and glucuronic acid. In its synthesis a large number of genes are involved. Presence or absence of certain genes can thus lead to a synthesis of various acetans, which makes the strains with genes for acetan production most promising candidates for the synthesis of new extracellular polysaccharides. From 10 strains, water soluble extracellular polysaccharides were successfully isolated and purified, followed by hydrolysis to monosaccharides. The identity of monosaccharides was determined by thin-layer chromatography using sugar standards. Based on all these results, we have selected three strains, for which we assume that they are good candidates for the formation of new acetan-like polysaccharides. Analysis of their rheological properties revealed differences in their viscoelastic properties. Further analysis has to be performed with the aim to analyse their detailed physical and chemical properties.
Keywords:Acetic acid bacteria, biofilm, extracellular polysaccharides.


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