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  • Effectiveness of novel xylanases belonging to different GH families on lignin and hexenuronic acids removal from specialty sisal fibres

     Valenzuela Mayorga, Susana Valeria; Valls Vidal, Cristina; Roncero Vivero, Maria Blanca; Vidal Llucia, Teresa; Díaz Lucea, Pilar; Pastor Blasco, Francisco Ignacio Javier
    Journal of chemical technology & biotechnology
    Date of publication: 2014-03-01
    Journal article

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    BACKGROUNDThe effectiveness of xylanases on lignin removal from pulps differs widely depending on the enzyme family, the type of pulp and the bleaching sequence among other factors. Xylanases can also reduce the presence of undesirable hexenuronic acids in the papermaking fibers. The performance of non-commercial xylanases belonging to families GH10, GH30, GH30-CBM35 and GH11, and of the multicomponent xylanase from Paenibacillus barcinonensis for lignin and hexenuronic acids removal from sisal (Agave sisalana) has been evaluated.; RESULTSSisal pulps were bleached by an XP sequence, where X denotes the enzyme treatment and P a hydrogen peroxide extraction stage. Kappa number, brightness, viscosity and hexenuronic acid content of samples were determined. Sugars released from sisal pulps, other non-wood fibres and also eucalyptus fibres, by the treatment with xylanases were also analysed. The best results were obtained with the GH10 xylanase and with crude supernatants of P. barcinonensis, which produced a lignin removal of 23% and a reduction of 25% in the hexenuronic acid content of sisal pulps without a significant loss of viscosity.; CONCLUSIONThe release of sugars in the effluents from the X stage applied to sisal correlated with the effectiveness of the xylanases tested. The xylan content of wood and non-wood fibres, the type of xylan and its accessibility also had an influence on the xylanase activity on pulps. (c) 2013 Society of Chemical Industry

  • Enzymatic strategies to improve removal of hexenuronic acids and lignin from cellulosic fibers

     Valls Vidal, Cristina; Vidal Llucia, Teresa; Roncero Vivero, Maria Blanca
    Holzforschung
    Date of publication: 2014
    Journal article

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    Different enzymatic strategies were applied to improve lignin and hexenuronic acid (HexA) removal. Three laccases (L) with different redox potentials were applied in combination with 1-hydroxybenzotriazole or methyl syringate to softwood sulfite and hardwood kraft fibers. The enzymes with a high-redox potential from Pycnoporus cinnabarinus and Trametes villosa were found to be the most efficient. The bleaching efficiency was not significantly influenced by the presence or absence of HexA in the different types of lignocellulosic fibers. Subsequently, the lignin or HexA removal in the presence of different mediators was evaluated in eucalyptus fibers with the T. villosa laccase (TvL). Natural mediators removed only lignin, whereas the combinations of TvL with synthetic mediators removed both HexA and lignin. The mediator violuric acid (VA) was the most efficient as judged by the properties of fiber and effluent. A xylanase pretreatment stage was found to boost the access of the LVA system to HexA without affecting lignin in the pulp

  • Nuevas perspectivas sobre la evaluación del cayente de los tejidos de calada

     Carrera Gallissa, Enric
    Defense's date: 2014-03-28
    Universitat Politècnica de Catalunya
    Theses

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    Se hace una revisión bibliográfica de los diferentes indicadores de cayente propuestos por los investigadores textiles desde 1950 hasta 2013, identificando un total de 36 distintos, de los cuales se explica detalladamente tanto su principio geométrico como su forma cálculo, unificando el lenguaje de los diferentes parámetros del cayente. Se ponen a punto dos técnicas de evaluación del cayente: a) digitalización del drapómetro Cusick, y b) simplificación del ensayo del anillo.Se han calculado los 36 indicadores de cayente descritos para una muestra de 37 tejidos de calada comerciales de un amplio espectro de composiciones, gramajes y ligamentos mediante un drapómetro tipo Cusick digitalizado. Se han realizado un análisis de las correlaciones existentes entre los indicadores calculados y se han identificado como relevantes 7 indicadores. A continuación se ha realizado un análisis factorial de componentes principales observándose la existencia de 3 factores comunes, el primero explica la intensidad del cayente, el segundo la severidad y el tercero explica la simetría y la variabilidad de su forma. Paralelamente se ha realizado un análisis clúster para visualizar estos resultados. Finalmente se describe y valida experimentalmente un criterio para diferenciar la forma del cayente de tejidos con el mismo índice de cayente (DR%) mediante la aplicación secuencial de 4 indicadores. Se han analizado asimismo 7 indicadores de cayente y 4 parámetros del ensayo del anillo-UPC de 15 tejidos comerciales de pañería de diferentes composiciones, gramajes y ligamentos mediante correlaciones canónicas, encontrando la ecuación de regresión que relaciona el DR% con el parámetro ¿h¿ del ensayo del anillo, concluyendo que el método de ensayo del anillo puede ser utilizado a nivel industrial como herramienta para el control rutinario del cayente en los procesos de acabado de tejidos de pañeríaTambién se han analizado 42 tejidos de calada comerciales de diversas composiciones, ligamentos y gramajes, mediante el equipo FAST y una modificación del ensayo del anillo. Se concluye que la formabilidad, la rigidez a la flexión, la fuerza máxima de extracción y el tiempo necesario para alcanzar este punto son los parámetros que más contribuyen a la correlación entre el sistema FAST y el ensayo del anillo. Se han obtenido las ecuaciones de regresión entre los principales parámetros FAST y los principales parámetros del ensayo del anillo, según correlaciones canónicas. Mediante la modificación del ensayo del anillo propuesto en esta tesis puede determinarse de una forma rápida sencilla y económica, la formabilidad, propiedad que hasta ahora sólo podía obtenerse mediante el equipo FAST.Se analizan, también, 37 tejidos de calada comerciales de diversas composiciones, ligamentos y gramajes, mediante el sistema Kawabata (KES-F) y anillo-UPC. Se concluye que los parámetros KES-F: LT, WT, EMT B, 2HB son los que más contribuyen a la correlación entre el sistema KES-F y el ensayo anillo-UPC. Se han obtenido las ecuaciones de regresión entre los principales parámetros KES-F y los principales parámetros del ensayo anillo-UPC, según correlaciones canónicas. Para finalizar se ha sometido un tejido de calada de PES 100% a un proceso de acabado ¿silk-like¿ en una planta piloto mediante un plan experimental de dos factores (concentración de sosa cáustica y tiempo de vaporizado) a tres niveles cada uno, con el fin de analizar la influencia de las variables del proceso en el cayente y mano de los tejidos, así como la relación entre la pérdida de peso y las propiedades del tejido acabado.Se constata la existencia de una relación estadísticamente significativa entre la pérdida de peso del tejido y las variables de proceso estudiadas. El tiempo de vaporizado no afecta a ninguno de los indicadores de cayente seleccionados, si bien, en algunos, interactúa significativamente con la concentración de sosa cáustica, la cual afecta a tres de los cinco indicadores estudiados.

  • Application of surface enzyme treatments using laccase and a hydrophobic compound to paper-based media

     Cusola Aumedes, Oriol; Valls Vidal, Cristina; Vidal Llucia, Teresa; Roncero Vivero, Maria Blanca
    Bioresource technology
    Date of publication: 2013-01-11
    Journal article

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    A new approach for the hydrophobization of finished cellulosic substrates based on a previously reported enzymatic technique is proposed. Commercial finished paper was hydrophobized by using laccase from Trametes villosa in combination with lauryl gallate (LG) as hydrophobic compound. The efficiency of the method was increased by the use of a lignosulfonate as a natural dispersant to improve the surface distribution of LG on the paper, raise its hydrophobicity and help preserve the enzyme activity. No similar threefold effect from a single compound for the improvement of enzymatic treatments was previously reported. The influence of processing conditions including the LG dose, treatment time and temperature was also examined, resulting in further increased hydrophobicity. Efficient fiber bonding and chemical functionalization were confirmed by thorough washing and Soxhlet extraction of the paper. As shown here for the first time, enzyme treatments have the potential to improve the surface hydrophobicity of paper-based media.

    A new approach for the hydrophobization of finished cellulosic substrates based on a previously reported enzymatic technique is proposed. Commercial finished paper was hydrophobized by using laccase from Trametes villosa in combination with lauryl gallate (LG) as hydrophobic compound. The efficiency of the method was increased by the use of a lignosulfonate as a natural dispersant to improve the surface distribution of LG on the paper, raise its hydrophobicity and help preserve the enzyme activity. No similar threefold effect from a single compound for the improvement of enzymatic treatments was previously reported. The influence of processing conditions including the LG dose, treatment time and temperature was also examined, resulting in further increased hydrophobicity. Efficient fiber bonding and chemical functionalization were confirmed by thorough washing and Soxhlet extraction of the paper. As shown here for the first time, enzyme treatments have the potential to improve the surface hydrophobicity of paper-based media

  • An enzyme-catalysed bleaching treatment to meet dissolving pulp characteristics for cellulose derivatives applications

     Quintana Vilajuana, Elisabet; Valls Vidal, Cristina; Vidal Llucia, Teresa; Roncero Vivero, Maria Blanca
    Bioresource technology
    Date of publication: 2013-11
    Journal article

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    Bleached cellulose with good end-properties (~90% ISO brightness and 62% cellulose preservation) was obtained by using a totally chlorine-free biobleaching process (TCF). Unbleached sulphite cellulose was treated with Trametes villosa laccase in combination with violuric acid. This enzymatic stage (L) was followed by a chelating stage (Q) and then by a hydrogen peroxide stage reinforced with pressurized oxygen (Po), resulting to an overall LQPo sequence. The use of violuric acid was dictated by the results of a preliminary study, where the bleaching efficiency of various natural (syringaldehyde and p-coumaric acid) and synthetic mediators (violuric acid and 1-hydroxybenzotriazole) were assessed. The outstanding results obtained with laccase-violuric acid system fulfil most of the characteristics of commercial dissolving pulp, totally acceptable for viscose manufacturing or CMC derivatives, with the added advantage that the enzymatic treatment saved 2. h of reaction time and about 70% of hydrogen peroxide consumption, relative to a conventional sequence (Po)

    Bleached cellulose with good end-properties (_90% ISO brightness and 62% cellulose preservation) was obtained by using a totally chlorine-free biobleaching process (TCF). Unbleached sulphite cellulose was treated with Trametes villosa laccase in combination with violuric acid. This enzymatic stage (L) was followed by a chelating stage (Q) and then by a hydrogen peroxide stage reinforced with pressurized oxygen (Po), resulting to an overall LQPo sequence. The use of violuric acid was dictated by the results of a preliminary study, where the bleaching efficiency of various natural (syringaldehyde and p-coumaric acid) and synthetic mediators (violuric acid and 1-hydroxybenzotriazole) were assessed. The outstanding results obtained with laccase-violuric acid system fulfil most of the characteristics of commercial dissolving pulp, totally acceptable for viscose manufacturing or CMC derivatives, with the added advantage that the enzymatic treatment saved 2 h of reaction time and about 70% of hydrogen peroxide consumption, relative to a conventional sequence (Po)

  • A new biobleaching sequence for kenaf pulp: influence of the chemical nature of the mediator and thermogravimetric analysis of the pulp

     Andreu Terren, Maria Gloria; Barneto, A. G.; Vidal Llucia, Teresa
    Bioresource technology
    Date of publication: 2013-02
    Journal article

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    This paper evaluates five phenolic compounds as mediators for kenaf pulp biobleaching by laccase. The results have been compared with the treatment using a non-phenolic mediator, 1-hydroxybenzotriole and laccase alone. The influence of the nature of the chemical mediators used on various pulp properties is discussed. In addition to oxidizing lignin, the phenolic radicals formed in the process take part in condensation and grafting reactions in enzymatic stage. After biobleaching sequence (LP), syringaldehyde was shown to be the best phenolic mediator, allowing a delignification of 43% and 72% ISO brightness. These results were similar to the use of laccase alone due to the role as mediators of syringyl units resulting from oxidative lignin degradation. As a novelty, the study was supplemented with thermogravimetric analysis, with emphasis on the crystallinity degree of the cellulose surface and the aim of elucidating the action mechanisms of laccase-mediator systems on fiber.

  • Laccase-mediated coupling of nonpolar chains for the hydrophobization of lignocellulose

     Garcia Ubasart, Jordi; Vidal Llucia, Teresa; Torres Lopez, Antonio Luis; Rojas, Orlando J.
    Biomacromolecules
    Date of publication: 2013-04-09
    Journal article

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    We investigate the use of laccase enzymes to couple short nonpolar chains containing aromatic groups onto flax fibers and nanofibrillated cellulose (NFC) with different lignin contents. Trametes villosa, Pycnoporus cinnabarinus, and Myceliophthora thermophila were used to facilitate surface coupling and to produce materials with different levels of hydrophobicity. Heat treatment of fiber webs after lacccase-mediated coupling markedly increased the resistance to water absorption. The highest hydrophobization levels of flax fibers was achieved by coupling dodecyl 3,4,5-trihydroxybenzoate (HB-C12), which yielded water contact angles (WCAs) of 80-96 degrees and water absorption times (drop tests) of ca. 73 min. The results from apparent aromatic content and FTIR analyses confirmed the laccase-mediated coupling of HB-C12 onto the cellulose fibers. Ultrathin films of NFC were also used as substrates for enzyme-mediated hydrophobization with HB-C12. In these cases, WCAs in the range of 87-104 degrees were achieved, depending on the conditions. Quartz crystal microgravimetry (QCM) was used to study the dynamics and the extent of the coupling process onto cellulose. The results help to better understand the mechanisms involved in laccase-mediated hydrophobization and provide a proof of a biotechnological platform for the development of value-added fiber products.

    We investigate the use of laccase enzymes to couple short nonpolar chains containing aromatic groups onto flax fibers and nanofibrillated cellulose (NFC) with different lignin contents. Trametes villosa, Pycnoporus cinnabarinus, and Myceliophthora thermophila were used to facilitate surface coupling and to produce materials with different levels of hydrophobicity. Heat treatment of fiber webs after lacccase-mediated coupling markedly increased the resistance to water absorption. The highest hydrophobization levels of flax fibers was achieved by coupling dodecyl 3,4,5-trihydroxybenzoate (HB-C12), which yielded water contact angles (WCAs) of 80−96 degrees and water absorption times (drop tests) of ca. 73 min. The results from apparent aromatic content and FTIR analyses confirmed the laccase-mediated coupling of HB-C12 onto the cellulose fibers. Ultrathin films of NFC were also used as substrates for enzyme-mediated hydrophobization with HBC12. In these cases, WCAs in the range of 87−104 degrees were achieved, depending on the conditions. Quartz crystal microgravimetry (QCM) was used to study the dynamics and the extent of the coupling process onto cellulose. The results help to better understand the mechanisms involved in laccase-mediated hydrophobization and provide a proof of a biotechnological platform for the development of value-added fiber products

  • High cellulose-content alkaline pulps obtained by enzyme-assisted hemicelluloses removal

     Beltramino Heffes, Facundo; Valls Vidal, Cristina; Vidal Llucia, Teresa; Roncero Vivero, Maria Blanca
    International Symposium on Wood, Fiber and Pulping Chemistry
    Presentation's date: 2013
    Presentation of work at congresses

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    Several procedures have been studied in order to carry out the necessary modifications to ¿upgrade¿ paper-grade pulps to dissolving grade including various chemical and biotechnological procedures. Among the last ones, enzymes, and particularly xylanases have a special interest due to their specificity characteristics. In the present work, xylanases are applied on a bleached alkaline pulp (lignin content close to 1%) in order to eliminate xylans. To achieve the highest purity grade, it is desirable to remove as much hemicelluloses as possible. Xylanases are applied on a TCF bleached nonwood NaOH-AQ pulp from Sisal (Agave Sisalana) at different conditions (xylanase dose, reaction time and procedure). The aim of this research is to find the best conditions for this application and establish an enzymatic procedure for obtaining pulps with low xylans content from bleached alkaline pulps. And as a consequence, obtain high cellulose-content fibers with longer durability and improved characteristics

  • Functionalization of cellulosic substrates using a product derived from an enzymatic reaction

     Cusola Aumedes, Oriol; Valls Vidal, Cristina; Vidal Llucia, Teresa; Roncero Vivero, Maria Blanca
    International Symposium on Wood, Fiber and Pulping Chemistry
    Presentation's date: 2013
    Presentation of work at congresses

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    The present work describes a new method for the surface functionalization of cellulosic sheets, overcoming the limitations of the traditional treatments, which are usually performed using fibrous suspensions. The method consists in obtaining a product (post-enzymatic) derived from an enzymatic reaction using Laccase and a compound showing a specific property. The obtained product, which has aqueous consistency, is then applied to the surface of a finished paper sheet (or cellulosic substrate) by means of impregnation, spray, size-press, or other available surface deposition technique used in the industry. The functionalization is produced by means of physicochemical interaction between the product and the substrate. In the present research, the methodology is developed to achieve the hydrophobization of finished paper sheets using Lauryl Gallate (LG) as hydrophobic compound, and a laccase derived from Trametes Villosa, reaching absorption times of up to 4000 s and CA values around 130° as assessed by the water drop test (WDT) and contact angle measurements (CA) respectively.

  • Enzymatically treated sulphite pulp to give dissolving-pulp characteristics

     Quintana Vilajuana, Elisabet; Valls Vidal, Cristina; Vidal Llucia, Teresa; Roncero Vivero, Maria Blanca
    International Symposium on Wood, Fiber and Pulping Chemistry
    Presentation's date: 2013
    Presentation of work at congresses

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    Bleached cellulose with good end-properties (~90% ISO brightness, < 0.5 kappa number and substantially preserved cellulose integrity) was obtained by using a totally chlorine-free (TCF) biobleaching sequence. The initial pulp was subjected to an overall LQPo sequence. Unbleached sulphite cellulose was treated with Trametes villosa laccase (L) in combination with violuric acid (VA). This enzymatic stage was followed by a chelating stage (Q) and then by a hydrogen peroxide stage reinforced with pressurized oxygen (Po). The use of violuric acid was dictated by the results of a preliminary study, where the bleaching efficiency of various natural (syringaldehyde and pcoumaric acid) and synthetic mediators (violuric acid and 1-hydroxybenzotriazole) were assessed. The outstanding results obtained with laccase-violuric acid system fulfil the characteristics of commercial dissolving-grade pulp with the added advantage that the enzymatic treatment saved 2h of reaction time and about 70% of hydrogen peroxide consumption, relative to a conventional hydrogen peroxide sequence (Po)

  • Laccase from Pycnoporus cinnabarinus and phenolic compounds: can the efficiency of an enzyme mediator for delignifying kenaf pulp be predicted?

     Andreu Terren, Maria Gloria; Vidal Llucia, Teresa
    Bioresource technology
    Date of publication: 2013-03
    Journal article

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    In this work, kenaf pulp was delignified by using laccase in combination with various redox mediators and the efficiency of the different laccase-mediator systems assessed in terms of the changes in pulp properties after bleaching. The oxidative ability of the individual mediators used (acetosyringone, syringaldehyde, p-coumaric acid, vanillin and actovanillone) and the laccase-mediator systems was determined by monitoring the oxidation-reduction potential (ORP) during process. The results confirmed the production of phenoxy radicals of variable reactivity and stressed the significant role of lignin structure in the enzymatic process. Although changes in ORP were correlated with the oxidative ability of the mediators, pulp properties as determined after the bleaching stage were also influenced by condensation and grafting reactions. As shown here, ORP measurements provide a first estimation of the delignification efficiency of a laccase-mediator system

    In this work, kenaf pulp was delignified by using laccase in combination with various redox mediators and the efficiency of the different laccase–mediator systems assessed in terms of the changes in pulp properties after bleaching. The oxidative ability of the individual mediators used (acetosyringone, syringaldehyde, p-coumaric acid, vanillin and actovanillone) and the laccase–mediator systems was determined by monitoring the oxidation–reduction potential (ORP) during process. The results confirmed the production of phenoxy radicals of variable reactivity and stressed the significant role of lignin structure in the enzymatic process. Although changes in ORP were correlated with the oxidative ability of the mediators, pulp properties as determined after the bleaching stage were also influenced by condensation and grafting reactions. As shown here, ORP measurements provide a first estimation of the delignification efficiency of a laccase–mediator system.

  • Use of cyclic voltammetry as an effective tool for selecting efficient enhancers for oxidative bioprocesses: Importance of pH

     Aracri, Elisabetta; Tzanov, Tzanko; Vidal Llucia, Teresa
    Industrial & engineering chemistry research
    Date of publication: 2013-01-04
    Journal article

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    Seven natural phenols and two synthetic compounds were evaluated by means of cyclic voltammetry as enhancers for the oxidation of the lignin model compound veratryl alcohol (VAl) and a sulfonated lignin (SL). Their electrochemical behaviors and catalytic efficiencies (CEs) against both substrates were assessed as a function of pH. A general increase in CE of the phenols was for the first time observed in the oxidation of VAl at pH 7 and 8. Methyl syringate (MS), syringic acid (SRC), and syringaldehyde (SRD) exhibited the highest CEs against VAl among the studied phenolic compounds despite the reduced stabilities of their phenoxy radicals. This was a result of favorable stability−reactivity balances, which were apparently influenced by both the chemical structures of the enhancers and the experimental conditions. Violuric acid (VAc) proved the most efficient compound in oxidizing lignin, followed by SRD and MS, which showed regeneration in the interval of pHs studied

  • Blanqueig enzimàtic de pasta de kenaf emprant sistemes lacasa-mediador  Open access

     Andreu Terren, Maria Gloria
    Defense's date: 2013-04-15
    Department of Textile and Paper Engineering, Universitat Politècnica de Catalunya
    Theses

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    La present tesi s’emmarca dins d’una de les línies del Grup de Recerca Paperer i Gràfic (CIPAGRAF), del Departament d’Enginyeria Tèxtil i Paperera de l’Escola Tècnica Superior d’Enginyeries Industrial i Aeronàutica de Terrassa, encaminada a l’aplicacióde la Biotecnologia per desenvolupar nous sistemes enzimàtics per al blanqueig depastes i modificació de fibres cel·lulòsiques. La implantació d’etapes enzimàtiques en les seqüències de blanqueig de pasta de paper a nivell industrial continua essent, avui en dia, un dels principals reptes en el camp de la investigació paperera. La reducció de l’impacte ambiental, l’optimització de costos, així com el desenvolupament de productes paperers amb propietats noves i millorades, justifiquen l’estudi de noves seqüències enzimàtiques basades en l’aplicació de sistemes lacasa-mediador. La utilització d’una matèria prima renovable, el kenaf, està en sintonia amb el creixent interès de l’ús de fibres no fusteres per a l’obtenció de nous productes lignocel·lulòsics d’alt valor afegit. Així doncs, aquesta tesi es fonamenta en l’ús d’enzims per a blanquejar pasta de kenaf. Les seqüències de blanqueig enzimàtic estudiades consten de diferents tractaments amb el sistema lacasa-mediador (Etapa L). Les lacases utilitzades en aquesta etapa provenen dels fongs Pycnoporus cinnabarinus i Trametes villosa, les quals s’apliquen amb diferents mediadors naturals (compostos fenòlics derivats de la lignina) i amb un mediador sintètic. L’etapa enzimàtica es completa amb diferents etapes de blanqueig químic (quelant, peròxid d’hidrogen i peròxid d’hidrogen pressuritzat). Al final de les seqüències s’obtenen, en funció del mediador utilitzat en l’etapa enzimàtica, fibres de kenaf amb un alt contingut de cel·lulosa i altes blancors. En aquest sentit, en el transcurs de l’experimentació s’ha constatat la importància de la naturalesa química del mediador, ja que els diferents radicals fenoxi formats en l’etapa enzimàtica determinen la capacitat oxidativa del sistema lacasa-mediador. Per altra banda, els resultats obtinguts remarquen el paper de la composició química de la lignina de kenaf en el procés enzimàtic. La capacitat oxidativa de la lacasa augmenta en presència de pasta de kenaf i la quantitat d’àcids hexenurònics presents en la mateixa limita el grau de blancor assolit en els diferents tractaments, encara que el resultat final es semblant o superior a una pasta TCF convencional. L’aplicació de xilanases després de l’etapa enzimàtica lacasa-mediador es mostra efectiva en l’eliminació d’aquests àcids, essent una possible via de millora als tractaments proposats en la present tesi.

    The present thesis has been performed in the research group CIPAGRAF (Grup de Recerca Paperer i Gràfic) of the Departament d'Enginyeria Tèxtil i Paperera at the Escola Tècnica Superior d'Enginyeries Industrial i Aeronàutica de Terrassa. One of the research topics of the group is the application of enzymes in pulp biobleaching processes and in the modification of cellulosic fibers. The implementation of enzymatic stages in paper pulp bleaching sequences is, at present, one of the main challenges of the research in the paper industry. The application of laccase-mediator systems can lead to a reduction of environmental impact and to cost optimization, as well as to the development of paper-derived products with novel and improved properties. The use of a renewable raw material -kenaf- is in accordance with the growing interest in the utilization of non-wood fibers for the production of new high-added value lignocellulosic products. Consequently, the present thesis is based on the use of enzymes for kenaf pulp bleaching. The enzymatic bleaching sequences studied involve different treatments with the laccase-mediator system (Stage L). The two fungal enzymes used in this stage- Pycnoporus cinnabarinus and Trametes villosa laccases-have been assisted by different natural mediators (lignin-derived phenolic compounds) and a synthetic one. The enzymatic stage has been completed with different chemical bleaching stages (chelating, hydrogen peroxide and pressurized hydrogen peroxide). At the end of the sequences, kenaf fibers with high cellulose levels and brightness were obtained. The significance of the chemical nature of the mediator has been emphasized because the different phenoxy radicals formed in the enzymatic stage determine the oxidative capacity of the laccase-mediator system. In addition, the results obtained also show the role of the chemical composition of kenaf lignin in the enzymatic process. The laccase oxidative capacity increases in the presence of kenaf pulp, and the amount of hexenuronic acids present limits the degree of brightness. Nevertheless, for the enzymatic treatments, the final results are similar to or better than for a conventional chlorine-free treatment. The application of xilanases after the laccase-mediator stage has been shown to be efficient in hexenuronic acids removal, opening possible new improvements to the treatments reported in this work.

  • Biomodification of cellulose flax fibers by a new cellulase

     Garcia Ubasart, Jordi; Torres Lopez, Antonio Luis; Vila, Carlos; Pastor, Francisco J.; Vidal Llucia, Teresa
    Industrial crops and products
    Date of publication: 2013-01
    Journal article

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    The potential of the new cellulase Cel9B from Paenibacillus barcinonensis for the modification of cellulose flax fibers was for the first time assessed in this work. Cel9B treatments were found to enhance the development of properties during the refining of fibers, the precise effects depending on the enzyme dose used. Scanning electron micrographs showed the treatments to alter flax fiber surface and cause defibrillation, peeling and fiber wall removal. Zero-span tensile strength was determined to elucidate the changes in intrinsic resistance of cellulose fibers and solubilization of carbohydrates evaluated by HPLC. Low Cel9B doses resulted in improved tensile strength in handsheets and can thus be used to save energy in the refining process. Also, on equal tear resistance, handsheets had a higher tensile index. High doses of Cel9B raised the collapsibility and bonding potential of cellulose flax fibers and produced heavier handsheets. Cel9B also improved air permeance at low refining intensities. The results obtained in this work are useful in understanding the effects brought by cellulase Cel9B on flax fibers and provide a proof of a biotechnological platform for the development of added-value fiber products

    The potential of the new cellulase Cel9B from Paenibacillus barcinonensis for the modification of cellulose flax fibers was for the first time assessed in this work. Cel9B treatments were found to enhance the development of properties during the refining of fibers, the precise effects depending on the enzyme dose used. Scanning electron micrographs showed the treatments to alter flax fiber surface and cause defibrillation, peeling and fiber wall removal. Zero-span tensile strength was determined to elucidate the changes in intrinsic resistance of cellulose fibers and solubilization of carbohydrates evaluated by HPLC. Low Cel9B doses resulted in improved tensile strength in handsheets and can thus be used to save energy in the refining process. Also, on equal tear resistance, handsheets had a higher tensile index. High doses of Cel9B raised the collapsibility and bonding potential of cellulose flax fibers and produced heavier handsheets. Cel9B also improved air permeance at low refining intensities. The results obtained in this work are useful in understanding the effects brought by cellulase Cel9B on flax fibers and provide a proof of a biotechnological platform for the development of added-value fiber products

  • Paper functionalization by means of enzymatic surface treatments using hydrophobic compounds and lignosulfonates

     Cusola Aumedes, Oriol; Garcia Ubasart, Jordi; Valls Vidal, Cristina; Vidal Llucia, Teresa; Roncero Vivero, Maria Blanca
    European Workshop on Lignocellulosics and Pulp
    Presentation's date: 2012-08-30
    Presentation of work at congresses

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    In the present work an innovative method for achieving enzymatic surface functionalization on finished paper sheets is presented. A commercial filter paper was surface sized with laccase derived from Trametes Villosa, Lauryl Gallate (LG) as hydrophobic compound, and soluble lignin. Moreover, this study shows the positive influence of sulfonated lignin (SL) acting as a dispersant improving the surface distribution of the LG along the paper sheet. The hydrophobic behavior of obtained sheets is comparable to the commercial ones. Hydrophobicity was measured by the water absorption test, and the variation in the contact angle through time was monitorized by a contact angle goniometer. Hydrophobized paper absorption was compared with Teflon® in order to determine the evaporated and absorbed water amounts from the paper surface. The treatment time, was also studied

    Postprint (author’s final draft)

  • Nanofibrillated cellulose as reinforcement for high performance cement mortar composites

     Ardanuy Raso, Monica; Claramunt Blanes, Josep; Pares Sabates, Ferran; Aracri, Elisabetta; Vidal Llucia, Teresa
    European Conference on Composite Materials
    Presentation's date: 2012-06-25
    Presentation of work at congresses

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  • Effect of residual lignin and heteropolysaccharides in nanofibrillar cellulose and nanopaper from wood fibers

     Ferrer Carrera, Ana; Quintana Vilajuana, Elisabet; Filpponen, Ilari; Solala, Iina; Vidal Llucia, Teresa; Rodríguez Pascual, Alejandro; Laine, Janne; Rojas, Orlando J.
    Cellulose
    Date of publication: 2012-12
    Journal article

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    Unbleached (UN), oxygen-delignified and fully-bleached (FB) birch fibers with a residual lignin content of ca. 3, 2 and\1 %, respectively, were used to produce nanofibrillated cellulose (NFC) and nanopaper by using an overpressure device. The tensile index, elongation and elastic modulus of nanopaper were compared and the effect of residual cellwall components accessed. Under similar manufacturing conditions, UN NFC produced nanopaper with a density of 0.99 g/cm3, higher than that from FB NFC (0.7 g/cm3). This translated in much lower air permeability in the case of UN nanopaper (1 and 11 mL/min for UN and FB samples, respectively). Fundamentally, these observations are ascribed to the finer fibrils produced during microfluidization of UN fibers compared to those from lower yield counterparts(AFMroughness of 8 and 17 nm and surface areas of 124 and 98 m2/g for NFC from UN and FBfibers, respectively).As a result, values of stress at break and energy absorption of nanopaper from high yield fibers are distinctively higher than those from fully bleached NFC. Interactions of water with the surface and bulk materialwere affected by the chemical composition and structure of the nanofibrils. While UN nanopaper presented higher water contact angles their sorption capacity (and rate of water absorption) was much higher than thosemeasured for nanopaper from FB NFC. These and other observations provided in this contribution are proposed to be related to the mechanoradical scavenging capacity of lignin in high shear microfluidization and the presence of residual heteropolysaccharides.

    Unbleached (UN), oxygen-delignified and fully-bleached (FB) birch fibers with a residual lignin content of ca. 3, 2 and\1 %, respectively, were used to produce nanofibrillated cellulose (NFC) and nanopaper by using an overpressure device. The tensile index, elongation and elastic modulus of nanopaper were compared and the effect of residual cellwall components accessed. Under similar manufacturing conditions, UN NFC produced nanopaper with a density of 0.99 g/cm3, higher than that from FB NFC (0.7 g/cm3). This translated in much lower air permeability in the case of UN nanopaper (1 and 11 mL/min for UN and FB samples, respectively). Fundamentally, these observations are ascribed to the finer fibrils produced during microfluidization of UN fibers compared to those from lower yield counterparts(AFMroughness of 8 and 17 nm and surface areas of 124 and 98 m2/g for NFC from UN and FBfibers, respectively).As a result, values of stress at break and energy absorption of nanopaper from high yield fibers are distinctively higher than those from fully bleached NFC. Interactions of water with the surface and bulk materialwere affected by the chemical composition and structure of the nanofibrils. While UN nanopaper presented higher water contact angles their sorption capacity (and rate of water absorption) was much higher than thosemeasured for nanopaper from FB NFC. These and other observations provided in this contribution are proposed to be related to the mechanoradical scavenging capacity of lignin in high shear microfluidization and the presence of residual heteropolysaccharides

  • Enzymatic grafting of natural phenols to flax fibres: development of antimicrobial properties

     Fillat Latorre, Amanda; Gallardo Román, Óscar; Vidal Llucia, Teresa; Pastor Blasco, F.I. Javier; Díaz Lucea, Pilar; Roncero Vivero, Maria Blanca
    Carbohydrate polymers
    Date of publication: 2012-01-04
    Journal article

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    Unbleached flax fibres for paper production were treated with laccase from Pycnoporus cinnabarinus and low molecular weight phenols (syringaldehyde – SA, acetosyringone – AS and p-coumaric acid – PCA) to evaluate the potential of this treatment to biomodify high cellulose content fibres. After the enzymatic treatment with the phenols, an increase in kappa number was found, probably due to a covalent binding of the phenoxy radicals on fibres. Grafting was more evident in pulps treated with PCA (an increase of 4 kappa number points with respect to the laccase control was achieved). Paper handsheets from treated pulps showed antimicrobial activity against the bacteria tested: Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae. An important reduction on microbial count was obtained after incubation of liquid cultures of the bacteria with grafted handsheets. AS and PCA grafted fibres showed a high antibacterial activity on K. pneumoniae, getting a nearly total growth inhibition. AS fibres also caused a high reduction in bacterial population of P. aeruginosa (97% reduction). Optical properties of handsheets from treated pulps were also determined, showing a brightness decrease and increase in coloration, evaluated by CIE L*a*b* system, caused by the laccase induced grafting of the phenols. The results suggest that these low molecular weight phenols, covalently bound to the flax fibres by the laccase treatment, can act as antimicrobial agents and produce handsheets with antimicrobial activity

  • Enhancing the effectiveness of a laccase¿TEMPO treatment has a biorefining effect on sisal cellulose fibres

     Aracri, Elisabetta; Vidal Llucia, Teresa
    Cellulose
    Date of publication: 2012-03-09
    Journal article

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  • A new procedure for the hydrophobization of cellulose fibre using laccase and a hydrophobic phenolic compound

     Garcia Ubasart, Jordi; Colom Pastor, Josep Francesc; Vila, Carlos; Gomez Hernandez, Núria; Roncero Vivero, Maria Blanca; Vidal Llucia, Teresa
    Bioresource technology
    Date of publication: 2012-05
    Journal article

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    A new biotechnological procedure using laccase in combination with a hydrophobic phenolic compound (lauryl gallate) for the hydrophobization of cellulose fibres and internal sizing of paper was developed. Cellulose fibres from hardwood kraft pulp were incubated with laccase (Lac), in combination with lauryl gallate (LG). The Lac-LG treatment resulted in the internal sizing of paper, and also in significantly reduced water penetration in the handsheets and wettability of the paper surface. Paper was found not to be effectively rendered hydrophobic by LG alone. SEM images of the fibre network revealed the presence of the sizing agent: a product of the reaction between laccase and lauryl gallate. Binding of lauryl gallate to cellulose fibres was suggested by the increase in kappa number of the pulp and further confirmed by IR spectroscopy

  • Paper strength improvement by oxidative modification of sisal cellulose fibres with laccase-TEMPO system: Influence of the process variables

     Aracri, Elisabetta; Valls Vidal, Cristina; Vidal Llucia, Teresa
    Carbohydrate polymers
    Date of publication: 2012-01-04
    Journal article

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  • Investigating the structure-effect relationship of various natural phenols used as laccase mediators in the biobleaching of kenaf and sisal pulps

     Barneto, A. G.; Aracri, Elisabetta; Andreu Terren, Maria Gloria; Vidal Llucia, Teresa
    Bioresource technology
    Date of publication: 2012-03
    Journal article

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  • Access to the full text
    Nanofibrillated cellulose (NFC) as a potential reinforcement for high performance cement mortar composites  Open access

     Ardanuy Raso, Monica; Claramunt Blanes, Josep; Arevalo Peces, Raquel; Pares Sabates, Ferran; Aracri, Elisabetta; Vidal Llucia, Teresa
    Bioresources
    Date of publication: 2012-07-09
    Journal article

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    In this work, nanofibrillated cellulose (NFC) has been evaluated as a potential reinforcement for cement mortar composites. Two types of vegetable fibres with different composition and properties (cellulose content and microfibrillar angle), sisal, and cotton linters pulps, were initially characterized in order to assess their reinforcement capability. Sisal pulp was found to be most suitable as reinforcement for their brittle cementitious matrix. Nanofibrillated cellulose was produced by the application of a high intensity refining process of the sisal pulp. It was found that 6 hours of refining time was required to obtain the desired nanofibrillation of the fibers. Cement mortar composites reinforced with both the sisal fibers and the nanofibrillated cellulose were prepared, and the mechanical properties were determined under flexural test. The cement mortar composites reinforced with the nanofibrillated cellulose exhibited enhanced flexural properties, but lower values of fracture energy, than the ones reinforced with the conventional sisal fibres.

  • Laccase for biobleaching of eucalypt kraft pulp by means of a modified industrial bleaching sequence

     Moldes, Diego; Vidal Llucia, Teresa
    Biotechnology progress
    Date of publication: 2012-09
    Journal article

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    Biobleaching of kraft pulp is a possible application of laccase, but it has not been described in detail for complete industrial bleaching sequences yet. Therefore, in this work, the biobleaching of Eucalyptus globulus kraft pulp was performed using a modified industrial totally chlorine-free sequence. The modification consisted in the substitution of an enzymatic delignification stage, based on the application of laccase from Trametes villosa, for the first alkaline extraction one. The enzymatic stage was performed with several synthetic and natural mediators, namely 1-hydroxybenzotriazole (HBT), violuric acid (VA), methyl syringate, and syringaldehyde. Several pulp properties were analyzed after each stage of the bleaching process¿kappa number, ISO brightness, viscosity, and optical properties of CIEL*a*b* system. The new biobleaching sequence improved the pulp properties, in comparison to the conventional bleaching sequence, if HBT or VA was used as mediators. VA was selected as the best mediator of those tested and the effect of its concentration in the enzymatic stage was subsequently studied. Reducing the initial concentration by 30%, the same pulp quality was obtained, but if the reduction attained 60%, an important decrease in pulp integrity was detected. The modified bleaching sequence could improve the bleached pulp properties (kappa number 10%, ISO brightness 1%, and viscosity 5%) in comparison to the mill sequence

    Biobleaching of kraft pulp is a possible application of laccase, but it has not been described in detail for complete industrial bleaching sequences yet. Therefore, in this work, the biobleaching of Eucalyptus globulus kraft pulp was performed using a modified industrial totally chlorine-free sequence. The modification consisted in the substitution of an enzymatic delignification stage, based on the application of laccase from Trametes villosa, for the first alkaline extraction one. The enzymatic stage was performed with several synthetic and natural mediators, namely 1-hydroxybenzotriazole (HBT), violuric acid (VA), methyl syringate, and syringaldehyde. Several pulp properties were analyzed after each stage of the bleaching process—kappa number, ISO brightness, viscosity, and optical properties of CIEL*a*b* system. The new biobleaching sequence improved the pulp properties, in comparison to the conventional bleaching sequence, if HBT or VA was used as mediators. VA was selected as the best mediator of those tested and the effect of its concentration in the enzymatic stage was subsequently studied. Reducing the initial concentration by 30%, the same pulp quality was obtained, but if the reduction attained 60%, an important decrease in pulp integrity was detected. The modified bleaching sequence could improve the bleached pulp properties (kappa number 10%, ISO brightness 1%, and viscosity 5%) in comparison to the mill sequence

  • Multifuncional biopolymer-bases materials for modulatig the activites of chromic wound enzymes  Open access

     Francesko, Antonio
    Defense's date: 2012-11-29
    Department of Chemical Engineering, Universitat Politècnica de Catalunya
    Theses

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    This thesis focuses on the development of active multifunctional dressing materials and nanoparticle formulations with suitable exploitation characteristics for chronic wounds treatment. Chronic wounds a growing clinical challenge in the aging and/or reduced mobility population include pressure, venous, arterial and diabetic neuropathic ulcers. Due to the nonhealing character of these ulcers their management requires an intensive medical intervention at huge healthcare costs. The prolonged inflammation and elevated concentrations of oxidative and proteolytic enzymes in all chronic wounds, imposes the need for novel functional dressing materials to actively modulate the wound environment at molecular level and stimulate the healing process. Based on an extensive analysis of the current state-of-the-art in chronic wound healing, the proper dressings should combine both antimicrobial and enzyme inhibitory functions coupled to optimal hydrophilicity. Such integrated approach would allow for the suppression of the persistent inflammation and stimulation of the synthesis of the dermal tissue components. Biopolymers with intrinsic antimicrobial and wound repair properties appear as appropriate matrix materials to be further upgraded with bioactive molecules (therapeutics) that couple high reactivity with the ability to address specific targets in the biochemical environment of chronic wounds. Therapeutic devices can be designed in different forms depending on the particular clinical application, i.e. wound type and its characteristics. During the thesis realisation biopolymer-based platforms were generated in various designs and functionalised with active agents for controlled inhibition of major chronic wound enzymes. The capacity of all developed materials to inhibit proteolytic (e.g. collagenase) and oxidative (e.g. myeloperoxidase) enzymes involved in chronic inflammation was evaluated in vitro. In the first approach sponge-like biopolymer matrices were produced via freeze-drying technique and controlled chemical cross-linking. These matrices were further impregnated with natural polyphenolic compounds. Modulation of the deleterious wound enzyme activities was achieved upon release of active agent from the platform. The exploitation characteristics of the sponges, i.e. mechanical properties, biostability, biocompatibility, extent and duration of wound enzymes inhibition, were tuned by: the biopolymer composition, concentration of the cross-linking agent, and the proper selection of the bioactive phenolic compounds. The second approach aimed at the permanent functionalisation of the biopolymeric platforms with thiol-bearing compounds. In this case the active agent is expected to act from the platform, without being released into the wound. The obtained thiolated biopolymers were further processed into functional nanomaterials of different design: *Nanoscale films/coatings were built using a layer-by-layer approach for alternate deposition of oppositely charged polyelectrolytes. Naturally occurring glycosaminoglycans were used as counterions to cationic thiolated conjugates. *Nanoparticle formulations were obtained from thiolated conjugates in a one-step sonochemical process. In both cases the biopolymer thiolation degree was identified as a key factor for the successful fabrication of the multilayered coatings and nanoparticles, as well as to achieve control of the thickness/size of the functional nanomaterials. In addition, tuneable inhibition/adsorption of the deleterious enzymes coupled to fibroblast attachment/proliferation was observed by ruling the biopolymer modification degree.

  • Application of laccase-based systems for biobleaching and functionalization of sisal fibres  Open access

     Aracri, Elisabetta
    Defense's date: 2012-01-27
    Department of Textile and Paper Engineering, Universitat Politècnica de Catalunya
    Theses

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    This research project originated from interest in assessing the potential of enzyme technology (particularly laccase-based systems) for the biomodification of sisal specialty fibres by using environmentally friendly processes. This doctoral work focused on two different research lines, namely: biobleaching and enzymatic functionalization of sisal pulp fibres. The study was started by assessing the use of natural, potentially cost-effective phenolic compounds as substitutes for expensive, potentially toxic laccase mediators. The tendency of natural phenols to either promote delignification or couple onto pulp was examined with a view to assessing their potential for either bleaching or functionalizing sisal fibres. In the biobleaching study, totally chlorine free (TCF) sequences were implemented in order to compare the efficiency of a selected natural mediator and a well-known synthetic mediator, both in the presence and absence of a xylanase pre-treatment. The effluents resulting from each stage in the sequence were analysed with a view to assessing the environmental impact of the laccase treatments ¿a scarcely explored aspect of biobleaching sequences. The xylanase stage proved highly efficient in reducing the HexA content of sisal fibres and in boosting the bleaching effect of the laccase treatments. The proposed TCF sequences provided high-cellulose sisal pulp with brightness above 80% ISO and a reduced HexA content; also, they exhibited improved performance and a reduced impact on effluent properties relative to the use of the synthetic mediator. Two different approaches to fibre functionalization were explored, namely: lignin modification (biografting) and cellulose modification (laccase¿TEMPO oxidation). Biografting of phenolic compounds was for the first time studied in sisal pulp. Covalent binding of the originally assayed phenolic compounds to sisal fibres during the laccase treatment was exposed by a novel analytical approach based on pyrolysis-GC/MS. The phenolic compound showing the highest tendency to couple to fibres was selected to investigate biografting under different reaction conditions and to evaluate the extent of phenol coupling via various pulp properties. Biografting efficiency was enhanced by refining the fibres prior to the enzyme treatment, which provided improved strength-related properties in the resulting paper. The use of the laccase-TEMPO system to oxidatively modify cellulose and improve strength-related properties in sisal pulp was for the first time evaluated as an environmentally friendly alternative to existing halide-based systems. The first part of this study revealed that the laccase¿TEMPO system considerably improved wet strength in sisal pulp by effect of the formation of a substantial amount of aldehyde groups in cellulose chains that facilitated inter-fibre bonding through hemiacetal linkages. The influence of process variables on various properties of the oxidized fibres and resulting paper was assessed by using a three-variable statistical plan. The conditions maximizing functionalization and the improvement in paper strength properties were used to design treatments of increased efficiency that exposed the potential of laccase¿TEMPO oxidation for biorefining pulp fibres. Analytical methods including pyrolysis-GC/MS, polyelectrolyte titration, conductimetric titration, carbohydrate determination by HPLC, fibre morphology analysis by SEM and thermogravimetry were used to both characterize the raw material and gain a better understanding of the reaction mechanisms behind the different laccase-based treatments. Some of the analyses were performed by collaborating research groups at IRNAS (Seville, Spain) and the Department of Chemical Engineering of the University of Huelva (Spain). Also, part of this doctoral work was conducted at the Institute of Paper Science and Technology of the Georgia Institute of Technology (Atlanta, USA).

  • Comparative Study of the Effects Induced by Different Laccase-Based Systems on Sisal Cellulose Fibers

     Aracri, Elisabetta; Barneto, A. G.; Vidal Llucia, Teresa
    Industrial & engineering chemistry research
    Date of publication: 2012-03-14
    Journal article

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  • Elucidating the effects of laccase-modifying compounds treatments on bast and core fibers in flax pulp

     Fillat Latorre, Amanda; Roncero Vivero, Maria Blanca; Vidal Llucia, Teresa
    Biotechnology and bioengineering
    Date of publication: 2012-01
    Journal article

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  • Preparación enzimática acuosa aislada y su uso para la funcionalización de la superficie del papel o soportes celulósicos

     Cusola Aumedes, Oriol; Roncero Vivero, Maria Blanca; Valls Vidal, Cristina; Vidal Llucia, Teresa
    Date of request: 2012-06-04
    Invention patent

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    Preparación enzimática acuosa aislada y uso para la funcionalización de la superficie del papel o soportes celulósicos.

    En un primer aspecto, la presente invención se refiere a una preparación enzimática acuosa aislada obtenida a partir de la reacción de por lo menos una enzima oxidorreductasa, preferiblemente una lacasa, y por lo menos un producto natural o sintético, preferiblemente un compuesto natural, cuyo producto natural o sintético comprende en su estructura por lo menos un grupo fenol o alcohol, que opcionalmente tiene una o más cadenas hidrofóbicas, o por lo menos un grupo esterol.

    En un segundo aspecto, la presente invención se refiere a la utilización de dicha preparación enzimática acuosa aislada en la funcionalización de la superficie del papel o soportes celulósicos.

  • Effect of the laccase mediator system on the fibre properties of TCF bleached kraft pulp

     Cadena Chamorro, Edith Marleny; Cusola Aumedes, Oriol; Vidal Llucia, Teresa; Torres Lopez, Antonio Luis
    International Colloquium on Eucalyptus Pulp
    Presentation's date: 2011-05-11
    Presentation of work at congresses

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  • A new approach to the internal sizing of paper via biotechnological processes

     Garcia Ubasart, Jordi; Roncero Vivero, Maria Blanca; Vidal Llucia, Teresa
    International Colloquium on Eucalyptus Pulp
    Presentation's date: 2011-05-10
    Presentation of work at congresses

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    This work deals with the study of a new biotechnological procedure, employing laccase in combination with hydrophobic compounds, for the biomodification of fibres and the internal sizing of paper. Cellulose fibres from eucalyptus kraft pulp, unbleached and TCF bleached, were incubated with laccase, in combination with a series of hydrophobes. Laccase treatments of cellulose fibres with lauryl gallate conferred the lowest level of water penetration in handsheets. It was observed that the hydrophobization of paper was not possible using the hidrophobe alone. The coupling of lauryl gallate onto cellulose fibres was firstly denoted by kappa number analysis, and further demonstrated by IR spectroscopy. The internal sizing of paper proved to be effective regardless the lignin content of eucalyptus fibres

  • Study of the effects on bast and core flax fibres of laccase + mediator/phenol treatments

     Fillat Latorre, Amanda; Roncero Vivero, Maria Blanca; Vidal Llucia, Teresa
    Italian Meeting on Lignocellulosic Chemistry
    Presentation's date: 2011-09-05
    Presentation of work at congresses

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  • Laccase-TEMPO oxidation of sisal pulp for improving paper strength properties: influence of the operating conditions

     Aracri, Elisabetta; Valls Vidal, Cristina; Vidal Llucia, Teresa
    Science and technology of biomassess: advances and challenges
    Presentation's date: 2011-09-08
    Presentation of work at congresses

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    The oxidation of a low lignin content sisal pulp by laccase-TEMPO system has been investigated and evaluated as potential approach for improving the paper strength properties. TEMPO mediated oxidation was found to cause the formation of aldehyde and carboxyl groups in proportions dependent on the particular reaction conditons. The treatment was performed in acetate buffer pH 5 at room temperature and the influence of process variables (viz laccase dose, TEMPO dose and reaction time)on the properties of the pulp and the resulting handsheets was assessed by using a three-variable sequential statistical plan. The increase of aldehyde groups was found to be closely aligned with enhanced wet strength which was ascribed to the formation of inter-fibre convalent bonding through hemiacetal linkages

  • Performance of new and commercial xylanases for ECF and TCF bleaching of eucalyptus kraft pulp

     Valls Vidal, Cristina; Gallardo Román, Óscar; Vidal Llucia, Teresa; Pastor Blasco, F.I. Javier; Díaz Lucea, Pilar; Roncero Vivero, Maria Blanca
    Wood science and technology
    Date of publication: 2011-08
    Journal article

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    Since xylanases can differ widely in their bleaching efficiency, the performance of one new and two commercial xylanases was evaluated in an eucalyptus kraft pulp following XD (X: xylanase; D: chlorine dioxide) and XP (P: hydrogen peroxide) sequences. The new xylanase did not show a significant bleach boosting effect but increased the hexenuronic acid (HexA) removal by 10% after the D stage. The two commercial xylanases behaved in a different way, being one of them (XC) the most effective in increasing delignification (9%) and brightness (3%ISO). Its effectiveness was related to its greater action on releasing the xylan polymer, thus producing also a strong decrease in the HexA contents during the enzymatic stage (15%). All xylanases produced morphological changes in the fibre surfaces, but only with XC cracks and holes that improved the diffusion of reactives were observed. Finally, the best bleaching results were obtained with the XD sequence and therefore, a complete bleaching sequence XDEopD1 (Eop: alkaline extraction with oxygen and peroxide) was carried out with the best enzyme

  • Enzymatic treatments of pulp using laccase and hydrophobic compounds

     Garcia Ubasart, Jordi; Esteban, Alberto; Vila Babarro, Carlos; Roncero Vivero, Maria Blanca; Vidal Llucia, Teresa
    Bioresource technology
    Date of publication: 2011-02
    Journal article

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    The aim of this work was to develop an innovative method for the internal sizing of paper by use of laccase and hydrophobic compounds. Nine different products containing hydrophobic moieties were tested in combination with laccase derived from Trametes villosa on Eucalyptus globulus kraft pulp in order to assess their internal sizing capability. The strongest internal sizing effect was obtained with lauryl gallate (LG). Heat treatment of the handsheets was found to increase the resistance to water absorption of internally sized samples significantly. Tests were conducted under variable operating conditions, including enzyme and reactant doses and treatment time. In addition to altering the water absorption rate, internal sizing with the laccase–LG treatments was found to affect the mechanical and optical properties of the handsheets. As shown in this work, treatments based on laccase and a hydrophobic compound (particularly lauryl gallate), can provide a new, effective biotechnological method for the internal sizing of paper.

  • Use of thermogravimetric analysis to monitor the effects of natural laccase mediators on flax pulp

     Vila, Carlos; Barneto, A. G.; Fillat Latorre, Amanda; Vidal Llucia, Teresa; Ariza, J.
    Bioresource technology
    Date of publication: 2011-06
    Journal article

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  • Studying the effects of laccase-catalysed grafting of ferulic acid on sisal pulp fibers

     Aracri, Elisabetta; Roncero Vivero, Maria Blanca; Vidal Llucia, Teresa
    Bioresource technology
    Date of publication: 2011-05-26
    Journal article

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  • Flax fibre modification using enzyme systems to obtain high-value cellulose products  Open access  awarded activity

     Fillat Latorre, Amanda
    Defense's date: 2011-07-15
    Department of Textile and Paper Engineering, Universitat Politècnica de Catalunya
    Theses

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    The aim of this thesis is to modify flax pulp fibres (Linum usitatissimum) by more friendly environmental processes. Pulp and paper research is focussing through enzyme systems investigation for developing green chemistry technologies due to existing environmental concerns and to legal restrictions. Moreover, it exists also an increasing strategic interest in using flax fibres to obtain high-quality specialty papers. That is why we study the application of biotechnology as an efficient alternative to traditional industrial processes based on the use of chemical agents. This work is framed by two of the main research topics of the Paper and Graphic Specialty Laboratory in the Textile and Paper Engineering Department of the Universitat Politècnica de Catalunya. One research line is based on pulp bleaching and is focused basically on the study of enzymatic systems as biobleaching agents; the other research topic that has been recently introduced in our investigation group is the use of enzymes as functionalisation agents by promoting the grafting of several compounds. Laccase is the main enzyme used in this thesis; it is an oxidoreductase that can assist reactions in an eco-friendly way since laccase uses air and produces water as the only by-product. Moreover, laccase can work under mill conditions and has wide application potential. The first part of this thesis involved the use of enzymes to bleach flax pulp. The aim was to explore the potential of various natural mediators (lignin-derived compounds) for delignifying flax fibres in order to identify the most efficient and ecofriendly choice among them. Afterwards, we assessed the use of various enzyme delignification stages in an industrial bleaching sequence. The ensuing totally chlorine free (TCF) sequence comprised various laccase-mediator system treatments (L stage) followed by a by a chelating stage (Q stage) and a subsequent bleaching step with hydrogen peroxide (Po stage). A xylanase pretreatment was additionally carried out. Laccases used came from the fungi Pycnoporus cinnabarinus and Myceliophthora thermophila; the performance of several natural mediators was compared with the obtained with the application of various synthetic mediators. In addition, the lack of studies on the properties of effluents from the treatment of non-wood pulp with laccase and natural mediators led A-1 A-2 us to examine effluent properties upon biotreatments and after different bleaching stages. The results obtained warrant upscaling any of the biobleaching sequences for flax pulp as they provide sustainable flax fibre with a high cellulose content and brightness above 80% ISO. The use of xylanase pretreatment was found to efficiently remove HexA and enhance delignification by laccase.

  • Aplicació de nous sistemes enzimàtics per al refinatge i la modificiació de fibres cel.lulòsiques

     Garcia Ubasart, Jordi
    Defense's date: 2011-07-22
    Department of Textile and Paper Engineering, Universitat Politècnica de Catalunya
    Theses

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  • Biotechnical and biomimetic approaches for coating of textile surfaces and enhancement of cleaning formulations

     Díaz Blanco, Carlos
    Defense's date: 2011-12-19
    Department of Chemical Engineering, Universitat Politècnica de Catalunya
    Theses

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  • Utilització de fibres vegetals per a l'elaboració de morters de ciment d'altes prestacions (SHCC)

     Claramunt Blanes, Josep
    Defense's date: 2011-12-21
    Department of Construction Engineering, Universitat Politècnica de Catalunya
    Theses

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  • NUEVOS PROCESOS OBTENCION PRODUCTOS CELULOSICOS ALTO VALOR AÑADIDO

     Torres Lopez, Antonio Luis; Fillat Latorre, Amanda; Garcia Ubasart, Jordi; Cusola Aumedes, Oriol; Vidal Llucia, Teresa
    Participation in a competitive project

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  • Effects of laccase-natural mediator systems on kenaf pulp

     Andreu Terren, Maria Gloria; Vidal Llucia, Teresa
    Bioresource technology
    Date of publication: 2011-05
    Journal article

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  • Enzymatic treatments of pulp using laccase and hydrophobic compounds

     Garcia Ubasart, Jordi; Esteban Barbero, Alberto; Vila Babarro, Carlos; Roncero Vivero, Maria Blanca; Vidal Llucia, Teresa; Colom Pastor, Josep Francesc
    Paper technology and industry
    Date of publication: 2011-09-01
    Journal article

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  • Reutilization of effluents from laccase-mediator treatments of kraft pulp for biobleaching

     Moldes, Diego; Vidal Llucia, Teresa
    Bioresource technology
    Date of publication: 2011-02
    Journal article

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  • On hexenuronic acid (HexA) removal and mediator coupling to pulp fiber in the laccase/mediator treatment

     Cadena Chamorro, Edith Marleny; Du, Xueyu; Gellerstedt, Göran; Li, Jiebing; Fillat Latorre, Amanda; Garcia Ubasart, Jordi; Vidal Llucia, Teresa; Colom Pastor, Josep Francesc
    Bioresource technology
    Date of publication: 2011-02
    Journal article

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  • New possibilities of kraft pulp biobleaching with laccase and sulfonated mediators

     Moldes, Diego; Vidal Llucia, Teresa
    Process biochemistry
    Date of publication: 2011-03
    Journal article

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  • Assessing the use of xylanase and laccases in biobleaching stages of a TCF sequence for flax pulp

     Fillat Latorre, Amanda; Roncero Vivero, Maria Blanca; Vidal Llucia, Teresa
    Journal of chemical technology & biotechnology
    Date of publication: 2011-12
    Journal article

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  • Xylanase- and laccase-aided hexenuronic acids and lignin removal from specialty sisal fibres

     Aracri, Elisabetta; Vidal Llucia, Teresa
    Carbohydrate polymers
    Date of publication: 2011
    Journal article

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    This work was conceived to investigate for the first time the effectiveness of the combined use of xylanase and laccase for the removal of hexenuronic acids (HexA) and lignin from sisal pulp fibres. To this end, xylanase (X) and laccase (L) treatments were used in an XLQPo sequence (where Q denotes a chelating stage and Po an oxygen-reinforced peroxide multi-step treatment) that was applied to pulp in order to obtain sisal fibres with a high cellulose content. The results of the XLQPo sequence were compared with those of an LQPo sequence. The L stage of both sequences was performed in the presence of either the natural compound sinapyl aldehyde (SLD) or the synthetic compound violuric acid (VA), employed as mediators, in order to compare their efficiency in aiding pulp bleaching and HexA removal. Changes in HexA content and the contributions of lignin and HexA to kappa number during each sequence were examined. The xylanase treatment was found to remove 47% of lignin, 15% of xylan and 27% of HexA from the initial pulp, whereas the laccase–VA system removed 28% of HexA and exhibited higher efficiency than the laccase–SLD system in reducing kappa number and increasing brightness. In any case, when the X treatment was applied, the sequence including laccase–SLD treatment resulted in the strongest delignification effect. The effluents from each stage of the bleaching sequences were analysed for COD, colour and toxicity, which peaked after the L stage and were significantly higher with SLD than with VA

  • Wet strength development in sisal cellulose fibers by effect of a laccase¿TEMPO treatment

     Aracri, Elisabetta; Vidal Llucia, Teresa; Ragauskas, Arthur J.
    Carbohydrate polymers
    Date of publication: 2011-04
    Journal article

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