20 documents found, page 1 of 2
Effect of surfactants on enzymatic hydrolysis of PET
Fu, Jiajia; Feng, Jundan; Han, Ruijuan; Lu, Yuzheng; Cavaco-Paulo, Artur; Li, RongEnzyme is difficult to adsorb on the surface of high-crystallinity poly(ethylene terephthalate) fibers (PETcrystallinity of 48.56 %) due to the high hydrophobicity of PET fibers. Surfactants can effectively reduce the PET/water interface tension and improve the adsorption of enzyme on PET fibers, increasing the degradation of PET fibers promoted by enzyme. In this paper, different nonionic surfactants (Triton X...
Cellulose dissolved in ionic liquids for modification of the shape of keratin f...
Liu, Yuwei; Jing, Su; Carvalho, Diana; Fu, Jiajia; Martins, Madalena; Cavaco-Paulo, ArturThe methylimidazolium chloride ionic liquid (IL) was successfully used for the dissolution of cotton cellulose. IL and IL-cellulose were investigated by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy analyses. The obtained IL-cellulose was applied to wool and hair keratin fiber surfaces, forming a fine coating layer. From FT-IR and XRD analyses, the results suggested the reduction o...
Can laccase-assisted processing conditions influence the structure of the react...
Su, Jing; Fu, Jiajia; Silva, Carla; Cavaco-Paulo, ArturLaccase is a promiscuous enzyme that catalyzes the polymerization of a wide range of phenolic substrates. Diverse poly(catechol) products can be obtained depending on the reactor employed and modifications of the laccase enzyme. The generation of these different reaction products may be attributed to changes in the geometry of the enzyme active site induced by different environmental conditions.
Strategies for the synthesis of fluorinated polyesters
Zhao, Xiaoman; Noro, Jennifer Martins; Fu, Jiajia; Silva, Carla; Cavaco-Paulo, ArturIn this work we synthetized three fluorinated polyesters from dimethyl tetrafluorosuccinate (DMTFS), dimethyl hexafluoroglutarate (DMHFG), and dimethyl octafluoroadipate (DMOFA) and ethylene glycol. The influence of parameters like monomer's size, temperature, vacuum, ultrasound and catalyst, on the polyesters synthesis was evaluated. The conversion rates were assessed considering 1H NMR data and the results di...
Antimicrobial coating of textiles by laccase in situ polymerization of catechol...
Jing Su; Jennifer Noro; Silva, Sónia Carina; Fu, Jiajia; Qiang Wang; Ribeiro, Artur; Silva, Carla; Cavaco-Paulo, ArturTextile fabrics made up of cotton, wool, and polyethylene terephthalate (PET) were coated with poly(catechol) and poly(p-phenylenediamine) through the in situ enzymatic polymerization of catechol and p-phenylenediamine, assisted by laccase under high-pressure homogenization. All coated fabrics showed antimicrobial activity against both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) s...
Coloured and low conductive fabrics by in situ laccase-catalysed polymerization
Su, Jing; Noro, Jennifer Martins; Fu, Jiajia; Wang, Qiang; Silva, Carla Manuela Pereira Marinho; Cavaco-Paulo, ArturColoured and conductive fabrics were obtained through in situ laccase polymerization of catechol and p-phenylenediamine under high-pressure homogenization. Both monomers, catechol and p-phenylenediamine, were polymerized by different laccase forms, namely native, PEGylated and Epoxy-PEGylated. All the catalysts were placed inside a textile fabric bag which served simultaneously as enzyme support and as substrat...
Conductive cotton by in situ laccase-polymerization of aniline
Su, Jing; Shim, Euijin; Noro, Jennifer Martins; Fu, Jiajia; Wang, Qiang; Kim, Hye Rim; Silva, Carla Manuela Pereira Marinho; Cavaco-Paulo, ArturConductive cotton fabrics were obtained via in situ aniline polymerization by laccase from Myceliophthora thermophila under mild reaction conditions without the addition of strong proton acids. The reactions were conducted using two types of reactors, namely a water bath (WB) and an ultrasonic bath (US), and the role of a mediator, 1-hydroxybenzotriazol (HBT), on the laccase-assisted polymerization of aniline w...
Exploring PEGylated and immobilized laccases for catechol polymerization
Jing Su; Noro, Jennifer Martins; Fu, Jiajia; Wang, Qiang; Silva, Carla; Cavaco-Paulo, ArturLaccases have been reported for their ability to eliminate hazardous phenolic compounds by oxidative polymerization. The exploitation of the oxidative behavior of different laccase forms, namely free/native, free/PEGylated, immobilized/native and immobilized/PEGylated, was assessed in this study. We found that PEGylated and immobilized laccase forms have differentiated catalytic behavior revealing distinct conv...
Enzymatic polymerization of catechol under high-pressure homogenization for the...
Su, Jing; Noro, Jennifer Martins; Fu, Jiajia; Wang, Qiang; Silva, Carla; Cavaco-Paulo, ArturLaccase from Myceliophthora thermophila was used to catalyze the polymerization of catechol under high-pressure homogenization for the green coloration of textile substrates. The oxidation reactions were conducted using different forms of laccase, namely native laccase, PEGylated laccase and PEGylated laccase immobilized onto an epoxy resin. The three enzyme forms were deposited inside a polyester fabric bag du...
Practical insights on enzyme stabilization
Silva, Carla; Sá, M.; Jing Su; Fu, Jiajia; Cavaco-Paulo, ArturEnzymes are efficient catalysts designed by nature to work in physiological environments of living systems. The best operational conditions to access and convert substrates at the industrial level are different from nature and normally extreme. Strategies to isolate enzymes from extremophiles can redefine new operational conditions, however not always solving all industrial requirements. The stability of enzyme...