Preizkus molekularnih lepil za nadzorovano agregacijo celic kvasovke Saccharomyces cerevisiae

Jovanovski, Maša (author), Osojnik Črnivec, Ilja Gasan (mentor), Jamnik, Polona (comentor)

Mikrokapsulacija mikrobnih celic je privlačna tehnika za mnogo aplikacij, saj lahko s takšno nadzorovano agregacijo zaščitimo celice pred inhibitorji iz okolja, povečamo produktivnost procesa, olajšamo ponovno uporabo celic ali zagotovimo zaščito in sproščanje celic v zaželenih pogojih. V magistrski nalogi smo preučili metodo koacervacije polisaharidov za sočasno agregacijo celic kvasovk Saccharomyces cerevisiae. Kot glavni nosilni polimer smo izbrali hitozan, v kombinaciji s hitozanom pa smo testirali tudi dodatne komponente: (i) ciklodekstrine (CD) – α, β, γ, in/ali (ii) alginat v različnih koncentracijah. Opazovali smo oblikovanje velikosti agregatov skozi čas ter odstotek celic, ki so se ujele v agregate oziroma, ki so ostale proste. Dognali smo, da različni testirani CD niso bistveno vplivali na agregacijo in velikost delcev, medtem ko smo z različnimi koncentracijami alginata opazno vplivali na pridobljene agregate. V vseh vzorcih so nastali agregati velikosti med 50 in 100 μm, z izjemo vzorca, ki je vseboval hitozan (1 mg/mL) in alginat (1 mg/mL), kjer so nastali agregati večji od 1 mm. Največji odstotek celic (60,7 %) smo ujeli v agregate s hitozanom (1 mg/mL) in alginatom (0,5 mg/mL), najmanj (25,4 %) pa v vzorcu s hitozanom (1 mg/mL) in alginatom (0,25 mg/mL). Izmed CD se je pri uspešnosti vezave celic v agregate najbolje (56,8 %) odrezal γ-CD, vrednosti v prisotnosti α-CD (40,8 %) in β-CD (43,6 %) pa so bile nekoliko manjše. V nalogi smo spremljali tudi viabilnost v agregate ujetih celic, kjer smo po 24 urah v vzorcih določili odstotek viabilnih celic med 77,5 % in 92,9 %. Razvita metoda za nadzorovano agregacijo S. cerevisiae je enostavna, hitra in hkrati ne zahteva dragih namenskih naprav ali tehnično zahtevne izvedbe ter je kot taka primerna tudi za izvedbo v aseptičnih pogojih.

• Language: Slovenian
• Keywords: mikrokapsulacija, kvasovke, Saccharomyces cerevisiae, hitozan, ciklodekstrini, alginat
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Publisher: [M. Jovanovski]
• Year: 2023
• PID: 20.500.12556/RUL-151045
• UDC: 544.77:579.6:582.282.23:615.014.6
• COBISS.SI-ID: 166180355
• Publication date in RUL: 28.09.2023

JOVANOVSKI, Maša, 2023, Preizkus molekularnih lepil za nadzorovano agregacijo celic kvasovke Saccharomyces cerevisiae [online]. Master’s thesis. M. Jovanovski. [Accessed 18 May 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=151045

Secondary language

• Language: English
• Title: Testing molecular glues for controlled aggregation of Saccharomyces cerevisiae yeast cells

Abstract

Microencapsulation of microbial cells is an attractive method for many applications. Controlled aggregation can protect cells from environmental inhibitors, increase the productivity of the process, facilitate the reuse of cells, or ensure the protection and release of cells under desired conditions. In this master's thesis, we studied the polysaccharide coacervation method for simultaneous aggregation of Saccharomyces cerevisiae yeast cells. We chose chitosan as the main carrier polymer, and in combination with chitosan we also tested additional components: (i) cyclodextrins (CD) – α, β, γ, and/or (ii) alginate in different concentrations. We observed the formation of aggregate size over time and the percentage of cells that were entrapped in aggregates or that remained free. We concluded that the different tested CDs did not significantly affect the aggregation and particle size, while different concentrations of alginate significantly affected the obtained aggregates. Aggregates between 50 and 100 μm in size were formed in all samples, with the exception of the sample containing chitosan (1 mg/mL) and alginate (1 mg/mL), where aggregates larger than 1 mm were formed. The highest percentage of cells (60.7%) was captured in aggregates with chitosan (1 mg/mL) and alginate (0.5 mg/mL), and the lowest (25.4 %) in the sample with chitosan (1 mg/mL) and alginate (0.25 mg/mL). Among the CDs, γ-CD performed best (56.8%) in the success of binding cells into aggregates, while the values in the presence of α-CD (40.8%) and β-CD (43.6%) were slightly lower. In the thesis, we also monitored the viability of cells entrapped in aggregates. After 24 hours the percentage of viable cells was between 77.5% and 92.9% for all samples. The developed method for the controlled aggregation of S. cerevisiae is simple, fast and, at the same time, does not require expensive machines or technically demanding implementation, and as such is also suitable for implementation in aseptic conditions.

• Keywords: microencapsulation, yeasts, Saccharomyces cerevisiae, chitosan, cyclodextrins, alginate