magistrsko delo
Nina Jančič (Author), Janja Trček (Mentor), Jure Škraban (Co-mentor)

Abstract

V magistrskem delu smo pri 23 izbranih sevih ocetnokislinskih bakterij iz rodov Komagataeibacter, Acetobacter, Asaia, Gluconobacter in Swaminathania preučevali sposobnost za tvorbo zunajceličnih polisaharidov in nato 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 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

magistrska dela;ocetnokislinske bakterije;biofilm;zunajcelični polisaharidi;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FNM - Faculty of Natural Sciences and Mathematics
Publisher: [N. Jančič]
UDC: 579.26:577.15:615.28(043.2)
COBISS: 24589832 Link will open in a new window
Views: 1203
Downloads: 83
Average score: 0 (0 votes)
Metadata: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Other data

Secondary language: English
Secondary title: Composition and viscoelastic properties of extracellular polysaccharides in selected strains of acetic acid bacteria
Secondary 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.
Secondary keywords: master theses;acetic acid bacteria;biofilm;extracellular polysaccharides;
URN: URN:SI:UM:
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za naravoslovje in matematiko, Oddelek za biologijo
Pages: VIII, 54 f.
ID: 11108374