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Comparative study of the effects induced by different laccase - based systems on sisal cellulose fibers / Elisabetta Aracri in Industrial & engineering chemistry research, Vol. 51 N° 10 (Mars 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 10 (Mars 2012) . - pp. 3895–3902 Titre : Comparative study of the effects induced by different laccase - based systems on sisal cellulose fibers Type de document : texte imprimé Auteurs : Elisabetta Aracri, Auteur ; Agustín G. Barneto, Auteur ; Teresa Vidal, Auteur Année de publication : 2012 Article en page(s) : pp. 3895–3902 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Sisal  cellulose  fibers Résumé : This paper reports a comparative study of the effects induced on sisal pulp fibers by three different laccase-based systems, namely, laccase–sinapyl aldehyde, laccase–ferulic acid, and laccase–TEMPO systems, applied to perform biobleaching, biografting, and cellulose oxidation, respectively. (The abbreviations SLD, FRC, and TEMPO are used to represent sinapyl aldehyde, ferulic acid, and the 2,2,6,6-tetramethylpiperidine-1-oxyl free radical.) A novel aspect of this study was the use of thermogravimetric analysis (TGA) to monitor surface changes in cellulosic microfibrils during the enzyme treatments and gain a greater understanding of the mechanisms of action of the laccase-based systems. The different modes of action of the studied laccase-based systems reflected in the different degradation profiles of pulps after treatment. TGA showed laccase to modify the thermal degradation path of the initial pulp, increasing the proportion of cellulose degrading at low temperature. The addition of SLD resulted in virtually no change of the thermal degradation path of the initial pulp, indicating that the laccase–SLD system basically exerted its action on the lignin component of fibers. In contrast to SLD, FRC was found to significantly increase the amount of the paracrystalline fraction of cellulose, probably as a consequence of its incorporation into fibers. The presence of TEMPO, especially under those conditions boosting the oxidative functionalization, was found to cause an intense degradation of cellulose and the formation of a substantial amount of amorphous cellulose degrading at low temperature. A novel aspect of the laccase–TEMPO system was identified in this work: its ability to reduce the hexenuronic acids (HexA) content content of pulp, under specific reaction conditions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2028206 [article] Comparative study of the effects induced by different laccase - based systems on sisal cellulose fibers [texte imprimé] / Elisabetta Aracri, Auteur ; Agustín G. Barneto, Auteur ; Teresa Vidal, Auteur . - 2012 . - pp. 3895–3902. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 10 (Mars 2012) . - pp. 3895–3902 Mots-clés : Sisal  cellulose  fibers Résumé : This paper reports a comparative study of the effects induced on sisal pulp fibers by three different laccase-based systems, namely, laccase–sinapyl aldehyde, laccase–ferulic acid, and laccase–TEMPO systems, applied to perform biobleaching, biografting, and cellulose oxidation, respectively. (The abbreviations SLD, FRC, and TEMPO are used to represent sinapyl aldehyde, ferulic acid, and the 2,2,6,6-tetramethylpiperidine-1-oxyl free radical.) A novel aspect of this study was the use of thermogravimetric analysis (TGA) to monitor surface changes in cellulosic microfibrils during the enzyme treatments and gain a greater understanding of the mechanisms of action of the laccase-based systems. The different modes of action of the studied laccase-based systems reflected in the different degradation profiles of pulps after treatment. TGA showed laccase to modify the thermal degradation path of the initial pulp, increasing the proportion of cellulose degrading at low temperature. The addition of SLD resulted in virtually no change of the thermal degradation path of the initial pulp, indicating that the laccase–SLD system basically exerted its action on the lignin component of fibers. In contrast to SLD, FRC was found to significantly increase the amount of the paracrystalline fraction of cellulose, probably as a consequence of its incorporation into fibers. The presence of TEMPO, especially under those conditions boosting the oxidative functionalization, was found to cause an intense degradation of cellulose and the formation of a substantial amount of amorphous cellulose degrading at low temperature. A novel aspect of the laccase–TEMPO system was identified in this work: its ability to reduce the hexenuronic acids (HexA) content content of pulp, under specific reaction conditions. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2028206