Effect of cellulase family and structure on modification of wood fibres at high consistency

Jenni Rahikainen*, Sara Ceccherini, Matthieu Molinier, Ulla Holopainen-Mantila, Mehedi Reza, Saija Väisänen, Terhi Puranen, Kristiina Kruus, Tapani Vuorinen, Thaddeus Maloney, Anna Suurnäkki, Stina Grönqvist

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    28 Citations (Scopus)

    Abstract

    Enzymatic modification of bleached softwood kraft fibres for improved fibre reactivity was studied at high (20% w/w) and low (1% w/w) dry matter content. The role of enzyme family and structure in fibre modification was assessed using endoglucanases from three structurally different glycoside hydrolase (GH) families (5, 7 and 45) with and without a carbohydrate binding module (CBM). Based on the amount of dissolved sugars, enzyme action at high consistency was about sixfold higher compared to a fibre treatment at low consistency. The GH45 endoglucanase was found to be most specific in acting on pulp cellulose whereas the family 5 and 7 endoglucanases had activity also on pulp hemicelluloses. The GH45 endoglucanase was found to be most efficient in reducing molecular weight and viscosity of the pulp. In addition, treatment with the GH45 endoglucanase resulted in the highest micropore volume in fibres and thus an increase in cellulose accessibility. The increased accessibility could be seen as decreased dissolution time in cupriethylenediamine using recently developed analytical techniques: viscometric analysis and microscopic video analysis. At high consistency, CBM was not promoting enzyme action, although CBMs are known to be beneficial at low dry matter conditions. Graphical abstract: [Figure not available: see fulltext.].

    Original languageEnglish
    Pages (from-to)5085-5103
    Number of pages19
    JournalCellulose
    Volume26
    Issue number8
    Early online date13 Apr 2019
    DOIs
    Publication statusPublished - 30 May 2019
    MoE publication typeA1 Journal article-refereed

    Keywords

    • Dissolution
    • Endoglucanase
    • Enzyme
    • Fibre
    • Fibre reactivity
    • High consistency

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