In this paper the oxidation of milled wood lignin (MWL), catalysed by three enzymes, i.e. laccase, tyrosinase and horseradish peroxidase (HRP) was studied. The oxidation was followed by measuring the consumption of O-2 during laccase and tyrosinase treatment and of H2O2 during HRP treatment. Both laccase and HRP were found to oxidise lignin effectively, whereas the effect of tyrosinase was negligible. The changes in MWL molecular-weight distributions caused in the reactions were analysed by gel permeation chromatography. Both laccase and HRP treatments were found to polymerise MWL. Peroxidase treatment was found to decrease the amount of phenolic hydroxyls in MWL, whereas no such effect could be detected in the laccase-treated sample. Both laccase and HRP treatments were, however, found to increase the amount of conjugated structures in MWL. The formation of phenoxy radicals during the treatments was studied by electron paramagnetic resonance spectroscopy. Phenoxy radicals were detected in both laccase and HRP-treated samples. The amount of the formed phenoxy radicals was found to be essentially constant during the detected time (i.e. 20-120 min after the addition of enzyme)

Gronqvist, S., Viikari, L., Niku Paavola, M., Orlandi, M., Canevali, C., Buchert, J. (2005). Oxidation of milled wood lignin with laccase, tyrosinase and horseradish peroxidase. APPLIED MICROBIOLOGY AND BIOTECHNOLOGY, 67(4), 489-494 [10.1007/s00253-004-1800-6].

Oxidation of milled wood lignin with laccase, tyrosinase and horseradish peroxidase

ORLANDI, MARCO EMILIO;CANEVALI, CARMEN;
2005

Abstract

In this paper the oxidation of milled wood lignin (MWL), catalysed by three enzymes, i.e. laccase, tyrosinase and horseradish peroxidase (HRP) was studied. The oxidation was followed by measuring the consumption of O-2 during laccase and tyrosinase treatment and of H2O2 during HRP treatment. Both laccase and HRP were found to oxidise lignin effectively, whereas the effect of tyrosinase was negligible. The changes in MWL molecular-weight distributions caused in the reactions were analysed by gel permeation chromatography. Both laccase and HRP treatments were found to polymerise MWL. Peroxidase treatment was found to decrease the amount of phenolic hydroxyls in MWL, whereas no such effect could be detected in the laccase-treated sample. Both laccase and HRP treatments were, however, found to increase the amount of conjugated structures in MWL. The formation of phenoxy radicals during the treatments was studied by electron paramagnetic resonance spectroscopy. Phenoxy radicals were detected in both laccase and HRP-treated samples. The amount of the formed phenoxy radicals was found to be essentially constant during the detected time (i.e. 20-120 min after the addition of enzyme)
Articolo in rivista - Articolo scientifico
Model Compounds; Phanerochaete-Chrysosporium; Catalyzed Oxidation; Fibers; Reactivity; Oxidases;Pulp
English
2005
67
4
489
494
open
Gronqvist, S., Viikari, L., Niku Paavola, M., Orlandi, M., Canevali, C., Buchert, J. (2005). Oxidation of milled wood lignin with laccase, tyrosinase and horseradish peroxidase. APPLIED MICROBIOLOGY AND BIOTECHNOLOGY, 67(4), 489-494 [10.1007/s00253-004-1800-6].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/2352
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