Enzymatic delignification and hexenuronic acid removal in cellulosic papermaking pulp using a haloperoxidase

A novel approach for lignin and hexenuronic acid (HexA) removal from cellulosic pulp based on the combination of a vanadium haloperoxidase (Hap) and the tertiary amine 1,4-diazabicyclo[2.2.2]octane (DABCO) as a co-catalyst was tested on oxygen-delignified kraft pulp. It was found that the addition o...

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Bibliographic Details
Published in:Green chemistry : an international journal and green chemistry resource : GC 2018, Vol.2 (3), p.649-657
Main Authors: Waschulin, Valentin, Loureiro, Pedro E. G, Herold-Majumdar, Owik M, Felby, Claus, Lund, Henrik
Format: Article
Language:English
Subjects:
Acids
Bleaching
Brightening
Brightness
Buffers
Catalysis
Catalysts
Cellulose
Degree of polymerization
Dry matter
Green chemistry
Haloperoxidase
Hydrogen peroxide
Kraft pulp
Lignin
Papermaking
pH effects
Polymerization
Pulp
Reduction
Selectivity
Sodium chloride
Vanadium
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Summary:A novel approach for lignin and hexenuronic acid (HexA) removal from cellulosic pulp based on the combination of a vanadium haloperoxidase (Hap) and the tertiary amine 1,4-diazabicyclo[2.2.2]octane (DABCO) as a co-catalyst was tested on oxygen-delignified kraft pulp. It was found that the addition of DABCO, likely through the formation of a reactive quaternary chlorammonium cation, consistently led to an unprecedentedly high lignin removal, HexA reduction and brightness gain in a one-stage enzymatic treatment. Under buffered conditions at pH 4.5 and 60 °C at 10% dry matter, using NaCl as an electron donor and H 2 O 2 as an electron acceptor and DABCO as a co-catalyst, high selectivity was achieved, leading to a considerable brightness gain and more than 80% of HexA removal without observing a reduction in the average degree of polymerization of cellulose. The treatment also showed superior HexA removal and selectivity compared to a conventional treatment based on hot acid hydrolysis (A-stage) when applied in a standard bleaching sequence. It was found important to control the pH in the Hap + DABCO stage, as under non-buffered conditions, the performance was inferior when compared to that of a non-enzymatic HOCl treatment. Hydrogen peroxide was proposed to contribute to the brightening during the Hap + DABCO stage. A novel approach for lignin and hexenuronic acid removal from cellulosic pulp based on the combination of a vanadium haloperoxidase and a tertiary amine co-catalyst.
ISSN:1463-9262
1463-9270
DOI:10.1039/c7gc03418k