Influence of antimicrobial treatment on biodegradation of cellulose textile substrates

doctoral dissertation

Darja Jaušovec (Avtor), Bojana Vončina (Mentor), Richard S. Blackburn (Komentor), Alenka Majcen Le Marechal (Komentor)

Povzetek

V doktorski disertaciji je bil proučen vpliv protimikrobnega sredstva 3-(trimetoksisilil)-propildimetiloktadecil amonijevega klorida (TMPAC) na biorazgradljivost dveh celuloznih substratov. V prvem delu naloge je bila preiskana biorazgradljivost TMPAC obdelane bombažne tkanine v primerjavi z neobdelano ob uporabi vrstične elektronske mikroskopije, FT-IR ATR spektroskopije, diferenčne dinamične kalorimetrije in z določanjem izgube mase. Iz rezultatov je bilo razvidno, da protimikrobno sredstvo TMPAC zmanjšuje stopnjo razgradnje bombažne tkanine, kar je bilo dokazano predvsem z morfološkimi in kemijskimi spremembami med procesom razgradnje. Kemijske spremembe so bile raziskane s pomočjo FT-IR ATR spektroskopije in dokazane zlasti s prisotnostjo amidnih in karboksilnih funkcionalnih skupin. Amidne funkcionalne skupine so nastale kot posledica prisotnosti proteinov nastalih z mikrobno rastjo, medtem, ko so karboksilne funkcionalne skupine nastale kot posledica oksidativne razgradnje celuloze. Dejstvo, da protimikrobno sredstvo TMPAC znižuje stopnjo razgradnje bombažne tkanine je bilo pojasnjeno z močno hidrofobnim značajem TMPAC obdelane površine, kar smo dokazali z večjim stičnim kotom TMPAC obdelanega bombaža v primerjavi z neobdelanim. V drugem delu naloge je bila proučena encimska razgradnja modelnega celuloznega filma obdelanega s protimikrobnim sredstvom TMPAC, v primerjavi z neobdelanim filmom ob uporabi mikroskopije na atomsko silo in elipsometrije. Uporabljene celulaze so bile pridobljene iz gliv Trichoderma viride in Aspergillus niger. Po dodatku encimov k modelnemu celuloznemu filmu, je po začetni adsorpciji encimov na substrat sledila nadaljnja razgradnja celuloze. Encimska razgradnja celuloze je bila dokazana s konstantno izgubo v masi filma ter z ne-monotonim obnašanjem v debelini filma, ki dokazuje, da encimi ne razgrajujejo samo površine filma ampak tudi penetrirajo v film. Učinkovitost uporabljenih celulaz je bila različna in veliko višja stopnja razgradnje je bila opažena pri uporabi celulaze Trichoderma viride. Stopnja razgradnje se je ob uporabi te celulaze očitno znižala, ko je bil celulozni film predhodno obdelan s protimikrobnim sredstvom TMPAC, medtem, ko pa protimikrobno sredstvo ni imelo pomembnega učinka na razgradnjo ob prisotnosti celulaze Aspergillus niger. Dokazano je bilo, da v odvisnosti od tipa celulaze, protimikrobno sredstvo TMPAC zavira encimsko učinkovitost na fazni meji trdno-tekoče. TMPAC povzroča hidrofobnost modelnega celuloznega filma in s tem zavira adsorpcijo encimov na površino substrata.

Ključne besede

cellulose;biodegradation;antimicrobial agent;model cellulose film;enzymatic degradation;ellipsometry;

Podatki

Jezik:	Angleški jezik
Leto izida:	2010
Izvor:	[Maribor
Tipologija:	2.08 - Doktorska disertacija
Organizacija:	UM FS - Fakulteta za strojništvo
Založnik:	D. Jaušovec]
UDK:	677.4.016/.017:537.3(043.3)
COBISS:	253105664
Št. ogledov:	2785
Št. prenosov:	203
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Slovenski jezik
Sekundarni naslov:	Vpliv protimikrobne obdelave na biorazgradljivost celuloznih tekstilnih substratov
Sekundarni povzetek:	The influence of the antimicrobial agent 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (TMPAC) on the biodegradation of two cellulose substrates was studied. Firstly, the biodegradation of TMPAC treated cotton fabric in comparison with untreated cotton fabric was investigated using Scanning Electron Microscopy (SEM), weight loss measurements, Fourier Transform Infrared Attenuated Total Reflectance (FT-IR ATR) spectroscopy and Differential Scanning Calorimetry (DSC). It was observed that the antimicrobial agent TMPAC decreases the degradation rate of the cotton fabric which was proven mostly by the morphological and chemical changes throughout the biodegradation process. The chemical changes were investigated by using FT-IR ATR spectroscopy and proven by the presence of amide groups as well as by the presence of carboxylic functional groups. Amide groups were produced as consequence of the proteins produced by microbial growth; meanwhile the carboxylic groups were produced as consequence of oxidative degradation of cellulose. The fact that the antimicrobial agent TMPAC decreases the degradation rate of cotton fabric is explained by the strong hydrophobic character of the TMPAC treated surface which was proven by the higher contact angle for TMPAC treated cotton in comparison with untreated cotton fabrics. Secondly, the enzymatic degradation of model cellulose film treated with antimicrobial agent (TMPAC) in comparison with pure cellulose film was investigated by Atomic Force Microscopy (AFM) and by in situ-null ellipsometry. The cellulases used were extracted from Trichoderma viride and Aspergillus niger. After enzyme addition to the previously equilibrated cellulose film, the initial enzyme adsorption on the substrate was followed by the cellulose film degradation. The enzymatic degradation of cellulose was proven by a constant loss of the film mass and a non-monotonous behaviour of the film thickness which suggest that the enzymes degrade not only the top of the surface but also penetrate into the cellulose film. The activities of the two enzymes were different, a much higher degradation rate being observed for the Trichoderma viride cellulase. The degradation rate with this cellulase decreased significantly when the cellulose film was treated with the antimicrobial agent TMPAC, meanwhile the antimicrobial agent did not affect the cellulose degradation significantly in the presence of Aspergillus niger cellulase. Hence, it was demonstrated for the first time that, depending on the cellulase type, the antimicrobial agent can inhibit enzymatic activity at the solid-liquid interface. TMPAC causes hydrophobicity of the model cellulose film and thus inhibits the adsorption of the enzymes on the surface.
Sekundarne ključne besede:	celuloza;biorazgradljivost;protimikrobna sredstva;modelni celulozni film;encimska razgradnja;elipsometrija;
URN:	URN:SI:UM:
Vrsta dela (COBISS):	Doktorska disertacija
Komentar na gradivo:	Univ. Maribor, Fak. za strojništvo
Strani:	XI, 120 f.
Ključne besede (UDK):	applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;various industries;trades and crafts;razne industrije;obrti in rokodelstva;textile industry;tekstilna industrija;man-made fibres;umetna vlakna;mathematics;natural sciences;naravoslovne vede;matematika;physics;fizika;electricity;magnetism;electromagnetism;elektrika;magnetizem;elektromagnetizem;current electricity;electric current;electrokinetics;
ID:	995380