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Title:OKSIDOREDUKTAZNI ENCIMI KOT ALTERNATIVA KLASIČNI REDUKCIJI V PROCESIH BARVANJA Z INDIGOIDNIMI BARVILI
Authors:ID Božič, Mojca (Author)
ID Guebitz, Georg (Mentor) More about this mentor... New window
ID Kokol, Vanja (Comentor)
Files:.pdf DR_Bozic_Mojca_2010.pdf (2,64 MB)
MD5: D569835E4126F426CEF7EE5D2A4C166A
PID: 20.500.12556/dkum/5e8fe6d0-7eb4-4a78-b5d5-d8c0f5973fcb
 
Language:Slovenian
Work type:Dissertation
Organization:FS - Faculty of Mechanical Engineering
Abstract:Konvencionalni postopek barvanja z indigoidnimi redukcijskimi barvili vključuje kemično redukcijo barvil v leuko vodotopno obliko, ki poteka v visoko alkalnem mediju (pH 11-14) ob prisotnosti močnih reducentov (večinoma natrijev ditionit, Na2S2O4). Pri tem se tvorijo velike količine toksičnih kemikalij v odpadnih barvalnih kopelih. Zamenjava kemične redukcije z encimsko bi bila z ekološkega in ekonomskega vidika zelo atraktivna zaradi nižjih uporabljenih temperatur med procesom, odsotnosti dodatnih kemikalij in možnosti znižanja stroškov naknadnih obdelav kopeli. Bacillus subtilis je bil izbran za pridobivanje encimov (NADH reduktaz), sposobnih redukcije indigoidnih barvil, s postopki čiščenja kot so percipitacija proteinov, ultrafiltracija/centrifugacija in kromatografija. NADH reduktaze so bile zmožne reducirati Acid Blue 74 in Natural Orange 6 v prisotnosti stehiometrično porabljenega kofaktorja NADH, medtem ko je pri Vat Blue 1 bila potrebna še prisotnost mediatorja 1,8-dihidroksiantrakinona. Vpliv mediatorja na encimsko redukcijo indiga in prisotnost različnih tekstilnih materialov je bil določen z ciklično voltametrijo. Leuko indigo anodični vrh je padal z nižanjem pH in v naslednjem redu uporabljenih materialov: bombaž, poliamid 6 in poliamid 6,6. Določene so bile barvne vrednosti, obstojnosti (na pranje, svetlobo in znoj) in mehanske obstojnosti (natezna trdnost in raztezek); in primerjane s kemično barvanimi materiali. Barvne vrednosti so bile odvisne od pH, časa, temperature barvanja in tipa tekstilnega materiala. Poliamida sta v primerjavi z bombažem dosegla boljše obarvanje. Barvne obstojnosti encimsko barvanih vzorcev so bile primerljive oziroma boljše kot kemično barvani vzorci. Modifikacijo, povzročeno z encimskim barvanjem, smo zasledovali s FTIR-ATR in refleksijsko spektroskopijo. Iz rezultatov je bilo razvidno, da je bil mediator popolnoma odstranjen iz vlaken po pranju in da ni prišlo do poškodb vlaken med encimsko obdelavo. Uspešna je bila ponovna uporaba encimske redukcijske kopeli pri pH 9 in pH 11, kjer so bila dobljena dobra oziroma odlična obarvanja tekstilnih vzorcev. Nazadnje je bila uspešno izvedena še encimska (NADH reduktaze) redukcija Acid Blue 74 v leuko obliko z uporabo regeneriranega NADH, pridobljenega z reakcijo dehidrogenaze iz Candida boidinii v isti kopeli.
Keywords:tekstilna vlakna, barvanje, redukcijska barvila, indigo, redukcija, oksidoreduktaze, biotehnologija
Place of publishing:[Maribor
Publisher:M. Božič]
Year of publishing:2010
PID:20.500.12556/DKUM-13731 New window
UDC:577.152.1:677.027.423.3(043.3)
COBISS.SI-ID:250918400 New window
NUK URN:URN:SI:UM:DK:QFGL2BQQ
Publication date in DKUM:06.05.2010
Views:4364
Downloads:393
Metadata:XML DC-XML DC-RDF
Categories:KTFMB - FS
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Secondary language

Language:English
Title:OXIDOREDUCTASE ENZYMES AS ALTERNATIVE TO CONVENTIONAL REDUCTION IN DYEING PROCESSES WITH INDIGOID DYES
Abstract:Conventional indigoid vat dyeing involves chemical reduction of dyes into their soluble leuco form in a high alkaline medium (pH 11 - 14) using powerful reducing agents (mostly sodium dithionite, Na2S2O4), generating considerable amounts of toxic chemicals in effluents. The replacement of the existing chemical reduction processes with enzymatic technologies could be ecological and economical attractive because of mild temperatures of processing, absence of by-products and possible reduction in the cost of treating the effluent. Bacillus subtilis was chosen for the production of indigoid dyes reducing enzymes, i.e. NADH reductases being purified by protein precipitation with ultrafiltration/centrifugation and chromatography steps. NADH reductase was shown to be able reduce Acid Blue 74 and Natural Orange 6 in the presence of the stoichiometrically consumed cofactor NADH, meanwhile Vat Blue 1 required also the presence of mediator 1,8-dihydroxyanthraquinone. The effect of the mediator on the enzymatic indigo reduction was studied by means of cyclic voltammetry, and in the presence of different textile materials, resulting to decreasing leuco indigo anodic peak in the order cotton, polyamide 6 and polyamide 6,6 and pH decrease. Colour values, fastness (to washing, light and perspiration) and mechanical (tensile strength and elongation) properties were evaluated and compared to chemically dyed fabrics. The results indicated that the dyeing properties were pH, time, temperature and fabrics type depended, resulting to the greater color depth for polyamides. The fastness properties of enzymatically dyed fabrics were comparable or even better than those obtained with chemically dyed fabrics. FTIR-ATR and reflection spectroscopy, employed to examine the modification of the fibre imparted by mediated enzymatic indigo dyeing, suggested completely removing of the mediator from the fibres after washing and no damages in fibers due to enzymatic treatment. The reuse of an enzyme-mediated reduction bath used in dyeing was assessed showing that the levelness of the obtained colour shade of the fabrics was either excellent or good at dyeings carried out at pH 9 and 11, respectively. In addition, the reduction of Acid Blue 74 to its leuco form by NADH reductase was confirmed using regenerated NADH by the oxidation of formic acid with formate dehydrogenase from Candida boidinii in the same solution.
Keywords:textile fibres, dyeing, vat dyes, indigo, reduction, oxidoreductase, biotechnology


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