Cusola, O.; Valls, C.; Vidal, T.; Tzanov, T.; Roncero, M.B. ACS applied materials and interfaces Vol. 7, num. 25, p. 13834-13841 DOI: 10.1021/acsami.5b01904 Data de publicació: 2015-06-09 Article en revista
In this work, we studied the influence of the alkyl chain length in enzymatically-oxidized gallates on the development of hydrophobicity on paper-based materials, and further correlated the obtained effect to the redox mechanism of the enzymatic treatment. Laccase (Lac) enzyme was used to oxidize various members of the gallate homologous series in the presence or not of lignosulfonates (SL) to produce several functionalization solutions (FS), which were subsequently applied to cellulosic substrates. The hydrophobicity of the substrates was then assessed by means of water drop test (WDT) and contact angle (WCA) measurements. Hydrophobicity peaked reaching WDT and WCA values around 5000 seconds and 130o respectively, and then decreased with increasing length of the hydrocarbon chain of gallate. Cyclic voltrammetry (CV) was used to study the effect of SL on the redox reactions of several gallates. The intensity of the anodic peak in their voltammograms decreased increasing the chain length of the gallate. The electrochemical behaviour of lauryl gallate (LG) differed from that of other gallates. The fact that the voltammetric curves for SL and LG intersected at a potential of 478 mV indicates an enhancing effect of SL on LG oxidation at high potentials (above 478 mV)
The covalent grafting of alkyl gallates on wool through a laccase catalysed reaction in 80/20 (v/v, %)aqueous–ethanol mixture provided in a one-step process a multifunctional textile material with antioxidant, antibacterial and water repellent properties. Gallic acid and its alkyl esters ethyl, propyl, octyl and
dodecyl gallate have been enzymatically grafted on wool fibres in order to study the effect of alkyl chain length on wool functional modification. The capacity of laccase to oxidise these phenolic compounds in an aqueous–organic medium has been verified by electrochemical techniques. The increase of CH2, CH3 groups in the FTIR spectra, together with the XPS analysis of the enzymatically modified fabrics confirmed
the covalent grafting of ester gallates on wool. The result obtained in this work for antibacterial, water repellent as well as antioxidant properties show that the length of the alkyl chain of gallates molecule
play an important role on wool functionalisation.
Electronic version of an article published as "Enzyme and microbial technology", 08 Desembre 2009, p. 1-5
Wool fibres have been modified with nordihydroguaiaretic acid (NDGA) to improve their performance at use. This water insoluble bi-functional phenolic compound has been grafted on wool through a laccase enzyme catalyzed reaction in an aqueous-ethanol mixture. The capacity of laccase to oxidise NDGA in this aqueous-organic medium has been studied electrochemicaly. The increase of CH2, CH3 and aromatic groups signal in the DRIFT spectra, together with SEM images of the enzymatically-modified fabrics confirmed the covalent grafting of NDGA on wool. This one step enzymatic process for grafting of NDGA improved the physical and mechanical properties of wool fabrics such as shrink resistance, crease recovery and tensile strength. Furthermore, the NDGA imparted to the textile material strong antioxidant activity and UV-protection.
'Hospital-acquired (nosocomial) infections are a major financial issue in the European healthcare system. The financial impact of these infections counteract medical advances and expensive medical treatments by increasing the length of hospital stay by at least 8 days on average per affected patient, hence adding more than 10 millions patient days in hospitals in Europe per year. The statistics on patient safety in the EU show alarming tendencies : - 1 in 10 patients are affected by hospital-acquired infections - 3 million deaths are caused by hospital-acquired infections An active infection control program of patients and personnel and hygiene measures, have proven to significantly reduce both the number of infections and hospitalisation costs . The SONO project directly addresses the above problems by developing a pilot line for the production of medical antibacterial textiles. The pilot line will be based on the scale-up of a sonochemical process developed and patented at BIU laboratories. The pilot line will use a sonochemical technique to produce and deposit inorganic, antimicrobial nanoparticles on medical textiles, e.g. hospital sheets, medical coats and bandages. Sonicators are used industrially for heavy and light duty cleaning, for water disinfection and for sewage treatment. It is also used in the food industry for emulsification and drying. The proposed concept based on one step sonochemical process to produce nanoparticles and impregnate them as antibacterial factors on textile is novel and does not exist on an industrial scale. The concept has already been proven (and patented ) on a lab scale where sonochemistry was applied to impregnate nanoparticles in a single-step process. It was demonstrated that due to the special properties of the sonochemical method the antibacterial nanoparticles are adsorbed permanently on the fibres even after 70 “laundry cycles”. The sonochemical impregnation process is a one-step procedure in which the nanopa'
A bioprocess for machine washable wool, combining the advantages of both protease and transglutaminase in a simultaneous enzymatic treatment has been developed. This process reduced the felting tendency of woven wool fabrics by 9% at the expense of only 2% weight and tensile strength loss. In contrast to previously described protease-based processes for shrink resistant wool, the anti-felting properties achieved in the simultaneous enzymatic treatment produced insignificant fibre damage, confirmed also by scanning electron images of the fabrics.
Calafell, M.; Diaz, C.; Hadzhiyska, H.; Gibert, J.; Daga, J.; Tzanov, T. Biocatalysis and biotransformation Vol. 25, num. 2-4, p. 336-340 DOI: 10.1080/10242420701379874 Data de publicació: 2007-03 Article en revista
Cotton fabrics were dyed with dyes generated in situ by laccase-catalyzed oxidative coupling of the colorless 2,5-diaminobenzenesulfonic acid (2,5-DABSA) and 1-hydroxyphenol (catechol). The enzymatic oxidation of the dye intermediates led to cross-coupling reaction products when the reaction was conducted with an excess of catechol. At least fourfold excess of catechol was necessary to achieve satisfactory dye fixation on cotton. Formation of the same colored product using either an equimolar ratio of the reagents or tenfold excess of catechol was observed. Most probably, homo-molecular reactions predominate over the cross-coupling at equimolar ratio of the precursors, while with an excess of catechol, the cross-coupling occurs in higher yield. The reaction was followed using UV-Vis spectroscopy, HPLC, FTIR and MALDI-TOF MS. A reaction pathway for laccase-induced cross-coupling of catechol and 2,5-DABSA yielding a major colored product was proposed.
Tzanov, T.; Calafell, M.; Gübitz, G. M,.; Cavaco-Paulo, A. Enzyme and microbial technology Vol. 29, num. 6-7, p. 357-362 DOI: 10.1016/S0141-0229(01)00388-X Data de publicació: 2001-09 Article en revista