Encontrados 8 documentos, a visualizar página 1 de 1

Interacção de ultra-sons com sistemas enzimáticos para aplicações têxteis

Tese de doutoramento em Engenharia Têxtil ; Ultrasound is sound with a frequency greater than the upper limit of human hearing. The application of ultrasound to liquid media is characterized by the occurrence of cavitation phenomena that results from the formation, growth and collapse of gas bubbles, subjected to alternating cycles of rarefaction and compression of waves. Cavitation promotes a number of physic...

Combined ultrasound-laccase assisted bleaching of cotton

This study evaluates the potential of using ultrasound to enhance the bleaching efficiency of laccase enzyme on cotton fabrics. Ultrasound of low intensity (7 W) and relatively short reaction time (30 min) seems to act in a synergistic way with the enzyme in the oxidation/removal of the natural colouring matter of cotton. The increased bleaching effect could be attributed to improved diffusion of the enzyme fro...

Stability and decolourization ability of trametes villosa laccase in liquid ult...

We report in this study that the sonication of laccase from Trametes villosa and bovine serum albumin promotes the formation of protein aggregates with high molecular weight. The formation of aggregates leads to the deactivation of the enzyme, fact that was confirmed by the analysis of the enzyme stability (half-life time) upon ultrasound treatment. This inactivation was mainly caused by the radicals formed by ...

Staining of wool using the reaction products of ABTS oxidation by Laccase : syn...

The effects of ultrasound on 2,2′-Azinobis(3-ethylbenzothiazoline-6-sulfonate) enzymatic oxidation by laccase (Trametes villosa) has been studied by means of cyclic voltammetry. The reaction was allowed to proceed in the presence of a piece of wool and the coloration depth of the wool fabric was measured by means of K/S. It was observed that cyclic voltammetry is influenced the dyeing process and higher K/S val...

Laccase-catalyzed polymerization for coating and material modification

The enzymatic polymerization and material modification with laccases is a promising technology especially for the coating of the natural and synthetic materials at mild conditions of temperature and pH [1]. The “in situ” enzymatic coating of several natural materials as sisal, linum, cotton and wood were performed, in a batchwise process at different temperature and pH. Small colorless aromatic compounds such a...

Sono-enzymatic coloration of wool

Sono-enzymatic polymerization of catechol

"Abstracts of papers presented at the 232nd American Chemical Society National Meeting" ; The potential of laccase enzymes for polymerizing, crosslinking and functionalizing various compounds was studied extensively and increasing interest has been focused on the application of this enzyme as a new biocatalyst in organic synthesis.[1-6] Laccases (EC 1.10.3.2) are a class of multi-copper-containing oxidoreducta...

Laccases to improve the whiteness in a conventional bleaching of cotton

This study reports for the first time on the enhancement of the bleaching effect achieved on cotton using laccase enzyme. Laccases applied in short-time batchwise or pad-dry processes prior to conventional peroxide bleaching, improved the end fabric whiteness. The whiteness level reached in the combined enzymatic/peroxide process was comparable to the whiteness in two consecutive peroxide bleaches. Effect of 10...