20.500.12556/DKUM-94252 Sinteza in karakterizacija magnetne bakterijske nanoceluloze diplomsko delo Synthesis and characterization of magnetic bacterial nanocellulose Bakterijska nanoceluloza (BNC) je naravni polimer, ki zaradi svojih edinstvenih lastnosti predstavlja obetavni izhodiščni material za številne nove razvojne pristope v inovativnih raziskavah na različnih področjih. Vendar pa čista BNC nima nekaterih lastnosti, zlasti magnetnih, ki pa jih je mogoče doseči z vgradnjo različnih vrst magnetnih nanodelcev (MNPs). Magistrsko delo obravnava sintezo magnetne bakterijske nanoceluloze v obliki kroglic (K-MBNC), ki predstavlja perspektiven material za uporabo v različnih biomedicinskih in tehnoloških aplikacijah. K-MBNC smo sintetizirali z dvema pristopoma; z in situ metodo, pri kateri smo MNPs sintetizirali neposredno v že pripravljene kroglice bakterijske nanonceluloze (K-BNC), in z metodo sinteze med fermentacijo, kjer smo MNPs dodali v gojitveni medij med postopkom sinteze K-BNC. Najprej smo proučevali parametre dinamične produkcije K-BNC z bakterijo Komagataeibacter xylinus. Nato je sledila študija produkcije KMBNC z različnima metodama. Pri obeh metodah sinteze K-MBNC smo spremljali vpliv sinteznih parametrov na magnetne, morfološke in fizikalno-kemijske lastnosti produktov. Rezultati kažejo, da hitrost stresanja in čas fermentacije vplivata na velikost, maso in število K-BNC. Višja hitrost stresanja zmanjša premer in poveča število nastalih K-BNC, daljši čas fermentacije pa poveča njihovo maso in velikost. Največjo maso K-MBNC, pridobljenih z metodo sinteze med fermentacijo, smo dosegli, ko je fermentacija potekala pri 26 °C, pH = 6 in s hitrostjo stresanja 140 rpm ter z dodatkom 0,5 g MNPs v medij. Koncentracija inokuluma je bila 1-5 × 106 CFU/mL. S SEM/EDS analizo smo potrdili uspešno vključitev MNPs v nanocelulozno matriko, pri čemer je in situ sintetiziran vzorec kazal bolj homogeno razporeditev in višji masni delež Fe. FTIR spektri vzorcev K-MBNC so vsebovali značilne vrhove za celulozo in Fe–O skupine, kar pravtako potrjuje uspešno sintezo magnetnega nanokompozita. TGA/DSC analiza je pokazala izboljšano termično stabilnost K-MBNC vzorcev v primerjavi s K-BNC. Meritve magnetnih lastnosti so pokazale, da K-MBNC sintetizirane in situ z manjšim premerom in uporabljenim razmerjem Fe3⁺ : Fe2⁺ = 2 : 1 kažejo boljšo magnetno odzivnost. Najboljše magnetne lastnosti K-MBNC, sintetiziranih z metodo sinteze med fermentacijo, izkazujejo kroglice sintetizirane s hitrostjo stresanja 140 rpm ter ob dodatku 0,5 g MNPs v medij. Sintetizirane K-MBNC, neglede na postopek sinteze, niso kazale protibakterijskega delovanja. Uspešno smo tudi prenesli sintezo K-MBNC med fermentacijo iz laboratorijskega merila v bioreaktorski sistem. Bacterial nanocellulose (BNC) is a natural polymer that, due to its unique properties, represents a promising starting material for numerous novel developmental approaches in innovative research across various fields. However, pure BNC lacks certain properties, particularly magnetic ones, which can be achieved by incorporating different types of magnetic nanoparticles (MNPs). This master’s thesis examines the synthesis of magnetic bacterial nanocellulose in bead form (K-MBNC), a promising material for use in various biomedical and technological applications. K-MBNC was synthesized using two approaches: an in situ method, in which MNPs were synthesized directly within pre-formed bacterial nanocellulose beads (K-BNC), and an agitated fermentation-synthesis method, in which MNPs were added to the culture medium during the synthesis of K-BNC. First, we studied the parameters of dynamic K-BNC production using the bacterium Komagataeibacter xylinus. This was followed by a study of K-MBNC production using the two different methods. For both synthesis approaches, the influence of synthesis parameters on the magnetic, morphological, and physicochemical properties of the products was examined. The results show that shaking speed and fermentation time influence the size, mass, and number of K-BNC. Higher shaking speed reduces bead diameter and increases bead number, whereas longer fermentation time increases bead mass and size. The highest mass of K-MBNC obtained via the agitated fermentation-synthesis method was achieved under fermentation at 26 °C, pH = 6, shaking speed of 140 rpm, and the addition of 0,5 g of MNPs to the medium. The inoculum concentration was 1–5 × 10⁶ CFU/mL. SEM/EDS analysis confirmed the successful incorporation of MNPs into the nanocellulose matrix, with the in situ synthesized sample showing a more homogeneous distribution and higher Fe content. FTIR spectra of K-MBNC samples exhibited characteristic peaks for cellulose and Fe–O groups, further confirming successful magnetic nanocomposite synthesis. TGA/DSC analysis demonstrated improved thermal stability of K-MBNC samples compared to K-BNC. Magnetic property measurements revealed that in situ synthesized K-MBNC with smaller bead diameter and an Fe3+ : Fe2+ ratio of 2 : 1 exhibited better magnetic responsiveness. The best magnetic properties of K-MBNC obtained via the agitated fermentation-synthesis method were observed in beads synthesized at a shaking speed of 140 rpm with the addition of 0,5 g of MNPs to the medium. Regardless of the synthesis method, the produced K-MBNC showed no antibacterial activity. Additionally, the agitated fermentation-synthesis method for K-MBNC was successfully scaled up from laboratory scale to a bioreactor system. bakterijska nanoceluloza Komagataeibacter xylinus magnetni nanokompoziti magnetni nanodelci bacterial nanocellulose Komagataeibacter xylinus magnetic nanocomposites magnetic nanoparticles true true false [K. Gajšt] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2025-08-11 13:03:18 2025-08-22 12:45:22 2025-09-08 08:03:37 0000-00-00 00:00:00 2025 0 Maribor 0 Maribor 1 spletni vir (1 datoteka PDF (X, 49 str.)) 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 620.3:661.728.7(043.2) 247865859 MAG_Gajst_Kaja_2025.pdf MAG_Gajst_Kaja_2025.pdf 1 524FC2CF75C099BBDFA4FC610CB3F611 9bbf692d11bc99aea3ea16b1d1675d429485a42490047260f497ff81f0e671b9 cba1ca1a-7f2f-11f0-a8d1-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=195925 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0