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Gewählte Publikation:

Huber, D; Ortner, A; Daxbacher, A; Nyanhongo, GS; Bauer, W; Guebitz, GM.
(2016): Influence of Oxygen and Mediators on Laccase-Catalyzed Polymerization of Lignosulfonate
ACS SUSTAIN CHEM ENG. 2016; 4(10): 5303-5310. FullText FullText_BOKU

Abstract:
Industrial utilization of lignin is of high interest since it represents around 30% of all nonfossil-based carbon sources worldwide. For various applications of lignosulfonates such as for dispersants or adhesives a larger molecular weight is essential. Here, we investigated laccase-catalyzed polymerization of lignosulfonate directly from the pulp and paper industry in the presence and absence of natural and synthetic mediators with and without oxygen supply. For example, laccase-mediated polymerization in the presence of a 2.5 mM TEMPO as mediator with a 10 cm(3) min(-1) oxygen flow rate led to a 12-fold increase of the molecular weight, while without TEMPO a 13-fold increase was achieved. In contrast, without an external oxygen supply, only a 7-fold increase in molecular weight was achieved compared to a 4-fold increase for the TEMPO-laccase system. Fluorescence intensity, phenol content, and size exclusion chromatography measurements indicate that generally in the presence of high concentrations of mediators, such as TEMPO, vanillin, HBT, and 2,6-dimethoxyphenol, oxidation of other structural units in lignosulfonates may counteract desired polymerization reactions. In summary, for laccase-catalyzed polymerization of lignosulfonates, an external oxygen supply was found to be much more beneficial than the presence of laccase mediators.
Autor/innen der BOKU Wien:
Daxbacher Andreas
Gübitz Georg
Huber Daniela
Nyanhongo Gibson Stephen
Ortner Andreas
BOKU Gendermonitor:


Find related publications in this database (Keywords)
Lignosulfonate
Laccase
Oxidation
Polymerization
Natural and synthetic mediators
Continuous oxygen supply


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