20.500.12556/RUL-126353 Kapsulacija kvasovk vrste Saccharomyces cerevisiae v polisaharidne nosilce Encapsulation of Saccharomyces cerevisiae yeasts into polysaccharide carriers Kvasovke Saccharomyces cerevisiae so med alkoholno fermentacijo izpostavljene hitremu spreminjanju fermentacijskega okolja. Visoka temperatura, visoka koncentracija substratov in produktov, pomankanje hranil in kisika jim predstavlja stres, pred katerim je kvasovke potrebno zaščititi. Mikrokapsulacija je tehnika, ki pridobiva vedno večjo vlogo v živilstvu in biotehnologiji. Raziskave so pokazale, da lahko z mikrokapsulacijo kvasovke zaščitimo pred stresnimi dejavniki v fermentacijskem okolju. V magistrski nalogi smo s kapsulatorjem BÜCHI 395–Pro pripravili mikrokroglice iz alginata, hitozana in pektina. Za kapsulacijo smo uporabili kulturo kvasovk S. cerevisiae ZIM 2155 iz Zbirke industrijskih mikroorganizmov Biotehniške fakultete. Spremljali smo potek alkoholne fermentacije s kapsulirnimi kvasovkami v gojiščih z veliko koncentracijo glukoze in pri visoki temperaturi fermentacije. Sproščanje kvasovk iz mikrokroglic smo spremljali z merjenjem vrednosti OD pri 650 nm, količino nastalega etanola in porabe glukoze smo analizirali z metodo HPLC. Ugotovili smo, da je kapsulacija uspešno zaščitila kvasovke pred veliko koncentracijo pridobljenega etanola v gojišču, saj so imele kapsulirane kvasovke boljši izkoristek. Kaspulacija je delno uspešno zaščitila kvasovke pred temperaturo fermentacije, 37 in 42 °C. Kapsulirane kvasovke so imele v gojišču pri 8 % glukoze in 37 °C ter v gojišču pri 24 % glukoze pri 37 in 42 °C boljši izkoristek od prostih kvasovk. Vseeno so dosegle nižjo koncentracijo etanola kot pri temperaturi 24 °C. Kapsulacija je vplivala na spremenjeno dinamiko porabe glukoze in nastajanja etanola. Izmed treh uporabljenih polisaharidov, se je za najbolj učinkovitega izkazal alginat. Pri uporabi mikrokroglic (240 ± 27 µm) iz alginata so kvasovke dosegle najboljše izkoristke in proizvedle največje koncentracije etanola (do 13,1 vol. % nastalega etanola). During alcoholic fermentation yeasts of Saccharomyces cerevisiae are exposed to rapid changes in the fermentative environment. High temperature, high concentration of substrates and products, lack of nutrients and oxygen are stress factors from which yeasts require protection. Microencapsulation is a technique that is gaining an increasing role in food industry and biotechnology. Research has shown that microencapsulation can protect yeasts from stress factors in the fermentative environment. In this master's thesis, we prepared microcapsules from alginate, chitosan, and pectin with a BÜCHI 395–Pro Encapsulator. Yeast strain S. cerevisiae ZIM 2155 from the Collection of Industrial Microorganisms of the Biotechnical Faculty was used for encapsulation. The course of alcoholic fermentation with encapsulated yeasts was monitored in media with high glucose concentration at high temperature. Yeast cell release from the microbeads was monitored by measuring the OD values at 650 nm, the amount of ethanol produced, and glucose consumption were analyzed by HPLC method. We found that encapsulation successfully protected yeasts from the high concentration of glucose and ethanol in the medium, as the encapsulated yeasts achieved better yields. Encapsulation only partially successfully protected the yeasts from the fermentation temperature of 37 and 42 °C. The encapsulated yeasts achieved better yields than free at 8 % glucose and 37 °C, and at 24 % glucose at 37 and 42 °C, but still produced lower ethanol concentration than at 24 °C. Encapsulation affected the kinetics of glucose consumption and ethanol production. Of the three polysaccharides used, alginate microbeads proved to be the most effective. When using alginate microbeads (240 ± 27 µm), the yeasts achieved the best yields and produced the highest concentrations of ethanol (up to 13,1 vol. %. of the resulting ethanol). kvasovke Saccharomyces cerevisiae mikrokapsulacija alkoholna fermentacija stresni dejavniki zaščita visoke temperature glukoza etanol izkoristek polisaharidni nosilci alginat hitozan pektin yeasts Saccharomyces cerevisiae microencapsulation alcoholic fermentation stressors protection high temperatures glucose ethanol yield polysaccharide carriers alginate chitosan pectin true false false [K. Maček] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2021-04-18 07:15:26 2021-04-18 07:15:35 2022-09-05 03:54:52 0000-00-00 00:00:00 2021 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 579.6:582.282.23:615.014.6 191131 60197379 12763.pdf 12763.pdf 1 B97C2CE868A25141708809945C7C23E1 ea1a4ad1ab911ac1a8dc0548114af670ae5d3c433f7d7fa21163f4e164643671 e43cbc6e-a1bb-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=142269 Biotehniška fakulteta 0 0 0