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Chitosan–lignosulfonates sono-chemically prepared nanoparticles : characterisat...
Kim, Suyeon; Fernandes, Margarida M.; Matamá, Maria Teresa; Loureiro, A.; Gomes, Andreia; Paulo, Artur CavacoDue to their recognised properties of biocompatibility, biodegradability and sustainability, chitosan nanocarriers have been successfully used as new delivery systems. In this work, nanoparticles combining chitosan and lignosulfonates were developed for the first time for cosmetic and biomedical applications. The ability of lignosulfonates to act as a counter polyion for stabilisation of chitosan particles, gen...
Enzymatic colouration with laccase and peroxidases : recent progress
Jiajia Fu; Nyanhongo, Gibson S.; Guebitz, G. M.; Paulo, Artur Cavaco; Kim, SuyeonEnzymes have received significant attention as alternative catalysts to chemical auxiliaries in textile processing. For example, laccases and peroxidises are promising alternatives for bleaching and denim stone washing processes. Similarly, the ability to oxidise different phenolic substrates and dye precusors resulting in the formation of different coloured polymeric molecules is being exploited for developing...
Polyoxometalate/laccase-mediated oxidative polymerization of catechol for texti...
Kim, Suyeon; Silva, Carla Manuela; Evtuguin, D. V.; Gamelas, José A. F.; Paulo, Artur CavacoThe synergistic effect between polyoxometalates (POMs), namely K5[SiW11VVO40]·11H2O and H5[PMo10 VV2O40]·13H2O and laccase from ascomycete Myceliophthora thermophila has been employed for the first time in oxidative polymerization of catechol. Such a laccase-mediator system allowed the formation of a relatively high molecular weight polycatechol as confirmed by size exclusion chromatography and electrospray ion...
In situ laccase-assisted overdyeing of denim using flavonoids
Guimarães, Clara; Kim, Suyeon; Silva, Carla Manuela; Paulo, Artur CavacoA laccase-mediated system for denim overdyeing using phenolic compounds was developed. Laccase from ascomycete Myceliophthora thermophila was able to oxidize phenolic compounds such as catechol and catechin and mediate their attachment to denim surfaces. Laccase-generated polymers gave rise to new coloration states from dark brown to green–yellow and replaced dyes in the overdyeing process. Process parameters, ...
Antimicrobial and antioxidant linen via laccase-assisted grafting
Silva, Carla Manuela; Matamá, Maria Teresa; Padrão, Jorge; Kim, Suyeon; Prasetyo, E. N.; Kudanga, T.; Nyanhongo, Gibson S.; Guebitz, G. M.A laccase from Ascomycetemyceliophthora thermophila was used to assist the binding of chitosan and catechin onto a previous enzymatically oxidized linen surface. The process consists of the pre-treatment of the linen with laccase followed by the application of chitosan in a first step and catechin plus laccase in a second step. The results presented here support the conclusion that laccase is able to oxidize ph...
Characterisation of enzymatically oxidised lignosulfonates and their applicatio...
Kim, Suyeon; Silva, Carla Manuela; Zille, Andrea; López, C.; Evtuguin, D. V.; Paulo, Artur CavacoThe ‘double function’ of laccase, from the ascomycete Myceliophthora, to depolymerise/polymerise lignin was studied in this work. A lignosulfonate (LS) compound was oxidised by enzymatic action and several techniques were applied to measure the polymeric changes obtained. This study was focused on the attachment level of the oxidised LS at the flax surface. RESULTS: Modified solutions were studied in terms of ...
Biological coloration of flax fabrics with flavonoids using laccase from tramet...
Kim, Suyeon; López, C.; Guebitz, G. M.; Paulo, Artur CavacoBiological environmentally friendly concepts are emerging to replace chemical treatments of fabrics. In this work, a new process for the coloration of flax fabrics via enzymatic oxidation of natural flavonoids (morin, quercetin) has been developed. Laccase from Trametes hirsuta is able to react with flavonoids and polymerize them, resulting in a strongly colored polymeric solution which can be applied to the co...
Enzymatic polymerization on the surface of functionalized cellulose fibers
Kim, Suyeon; Zille, Andrea; Murkovic, M.; Guebitz, G. M.; Paulo, Artur CavacoEnzymatic coating of functionalized cellulose fibers with catechol was performed in the presence of Trametes hirsuta laccase. Cellulose functionalization was done by covalent fixation of aromatic amines onto the cellulose surface using a dyeing procedure with C.I. Reactive Black 5 (RB5) followed by reduction with sodium hydrosulfite. Cellulase enzymes were used on coated and control samples to obtain the analyt...
Laccases for enzymatic colouration of unbleached cotton
Kim, Suyeon; Moldes, Diego; Paulo, Artur CavacoThe concept presented in this paper is the utilisation of the natural flavonoids present in cotton as anchors to attach other phenolic compounds to the fiber surface. Laccase can catalyze the oxidation of flavonoids in solution producing quinones that can be further polymerised and grafted onto surface of the cotton providing yellow to brown colouration, depending on the external flavonoids used and on the reac...
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