Margarita Calafell

• PhD
• Polytechnic University of Catalonia

Poly[(R)-3-hydroxybutyrate] (PHB) constitutes a biopolymer synthesized from renewable resources by various microorganisms. This work was focused on finding a new PHB-producing bacterium capable of growing in conventional media used for industrial biopolymer production, its taxonomical identification, and characterization of its biopolymer produced....

Postprint (published version)

The enzymatic degradation of bacterial poly[(R)-3-hydroxybutyrate] (PHB) was studied to obtain low-molecular-weight oligomers — between 5000 and 1000 Da, and to assess the possibility of a more controlled depolymerisation, by improving the polydispersity index (PDI) from an acid and alkaline hydrolysis on previous studies. We worked with three kind...

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 fourfo...

Poly-gamma-glutamic acid, or PGA, is a macromolecular compound obtained by biotechnological processes such as fermentation. It is a component of the cell wall of bacteria, especially of the genus Bacillus. It can be found as an eatable ferment (Natto) and it has been attributed several beneficial dietary properties. The PGA has been studied for use...

Durant aquest projecte s’ha recopilat i estructurat un material didàctic adequat perquè l’alumnat, en especial el que no hagi cursat assignatures de química abans del seu ingrés a la universitat, pugui aconseguir uns coneixements de química convenients per poder seguir eficaçment l’assignatura de Química I, corresponent a la fase selectiva de la ti...

Cultivation media for the production of both a cellulase containing and a cellulase-free polygalacturonase (PG) preparation by a highly productive strain of Sclerotium rolfsii (CBS 350.80) were developed. These enzyme preparations both contained a PG activity higher than 500 IUmL and were applied in a bioscouring sequence of knitted cotton at vario...

Bioscouring of cotton is normally carried out using pectinases having pectate lyase activity. The present study has examined the influence of pectate lyase and hydrolase on the surface of cotton fibre. Dye uptake by cotton scoured with polygalacturonase is found to be much lower than that scoured with pectate lyase, Pectate lyase gave better dye ex...

The effect of four different enzymatic bioscouring systems for cotton have been compared in regard to the dyeability of reactive, cationic and acid dyes. The residual pectin content was determined and the results assessed in terms of dyeability against control samples prepared in the absence of enzyme. The capacity of a bifunctional reactive dye to...

Cotton cellulose was dyed "in situ" with a polymeric dye generated by oxidative coupling of colourless 2,5-diaminobenzenesulfonic acid and 1-hydroxyphenol (catechol) with laccase. Up to 70% dye fixation was obtained increasing the concentration of catechol less soluble upon oxidation from 1 to 10 mmol, while 1 mmol of diamine was used. Dye fixation...

Textile industrial scouring processes are currently based on the use of chemical reagents that cause an important environmental impact. For some years, several research groups have focused on obtaining enzymes that can carry out the scouring task in an effective way, allowing at the same time a decrease of the industrial costs of water and energy a...

An analysis of variance has been applied to study the individual effects and the interaction between the process parameters, temperature, pH, and surfactant concentration, in the bioscouring of cotton fibers with an acid pectinase. This study indicates that increasing the temperature does not increase the total percentage of bioscouring but acceler...

This study attempted to introduce the bio-processes in the conventional scouring and bleaching preparation of cotton. The scouring with two types of pectinases, acting under acidic and alkaline conditions respectively, was as efficient as the chemical process in terms of obtained adequate water absorbency of the fabrics. The necessity of surfactant...

Peptide T is a non-natural octapeptide of sequence Ala-Ser-Thr-Thr-Thr-Asn-Tyr-Thr, taken from the sequence of the protein gp120 of HIV. The peptide has been shown to bind competitively to the CD4 receptors of the helper/inducer lymphocytes T. The peptide is presently used for the treatment of AIDS-associated dementia and has been proven useful for...

A study of an industrial process that reduces the raw materials, pollutants and energy in the scouring of the cotton fibre is presented. The application of a factorial design to a study of the significance of individual effects and the interaction between three parameters in the process are described. Temperature, pH control and use of surfactant....

The effect of accelerator content on the curing reaction of an epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) with methyl-tetrahydrophthalic anhydride was studied by DSC. The uncatalysed curing occurs at high temperature (between 190 and 310°C) with thermal degradation. The addition of accelerator which is a tertiary amine catalyst ag...

This work is aimed at studying the enzymatic hydrolysis of fats form milk serum and milk products and subsequent concentration and separation of volatil fatty acids (C4, C6 and C8) responsible for cheese flavour. The enzymes from fungi hydrolysed short chained fatty acids at a faster rate than the enzymes from pancreatic sources. The high concentra...