Characterisation of residual lignins in pulps delignified by laccase/N-hydroxyacetanilide

Kristiina Poppius-Levlin, Tarja Tamminen, Anna Kalliola, T. Ohra-aho

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

11 Citations (Scopus)

Abstract

A pine kraft pulp and a two-stage oxygen-delignified pine kraft pulp were delignified with laccase in the presence of N-hydroxyacetanilide (NHA). Laccase/NHA was selective in its reactions with lignin: 30% delignification was obtained under the moderate reaction conditions employed, while the carbohydrates remained unattacked. Laccase/NHA did not react with neutral pulp carbohydrates or with uronic acids. Beside delignification, laccase/NHA caused chemical modification of fiber lignin, lowering the content of free phenolic hydroxyl groups and thus verifying their importance in delignification. Oxidation of the residual lignins was clearly observed as a decrease in methoxyl groups and a simultaneous increase in conjugated carbonyl groups, carboxyl and/or ester groups. Only 50-60% of the pulp residual lignin retained its aromatic structure. Pyrolysis-GC/MS gave important information, not only of the chemical structure of residual lignins, but also of the behavior of the mediator during delignification. Residuals of aniline and acetanilide, i.e. degradation products of NHA, were found among thepyrolysis products of residual lignins. However, only trace amounts of NHA-derived nitrogen-containing products were present in the lignins.
Original languageEnglish
Title of host publicationOxidative Delignification Chemistry
Subtitle of host publicationFundamentals and Catalysis
EditorsD.C. Argyropoulos
PublisherAmerican Chemical Society ACS
Chapter22
Pages358-372
ISBN (Electronic)978-0-8412-1853-6
ISBN (Print)978-0-8412-3738-4
DOIs
Publication statusPublished - 2001
MoE publication typeA4 Article in a conference publication
Event219th American Chemical Society ACS National Meeting - San Francisco, United States
Duration: 26 Mar 200031 Mar 2000

Publication series

SeriesACS Symposium Series
Volume785
ISSN0097-6156

Conference

Conference219th American Chemical Society ACS National Meeting
CountryUnited States
CitySan Francisco
Period26/03/0031/03/00

Fingerprint Dive into the research topics of 'Characterisation of residual lignins in pulps delignified by laccase/<i>N</i>-hydroxyacetanilide'. Together they form a unique fingerprint.

Cite this