Refining of Pine radiata and eucalyptus kraft pulps assisted with commercial laccase mediator systems

Authors*: Michael Lecourt1
Adrien Soranzo1
Michel Petit-Conil2

SUMMARY
In the manufacture of papers, an important step is the refining of the
pulp to develop the strength properties. Today, to decrease the operating
costs, one way is to apply enzymes on the pulp before refining.
The objective of our work was to introduce laccase treatment to reduce
the electrical energy consumption and to enhance the pulp properties.
On a eucalyptus bleached kraft pulp, laccase associated to syringaldehyde
or a new mediator affected the refining behaviour. Lower
bulk values were measured for the biotreated pulps, fibres were
more flexible and more amenable to compaction during the sheet
formation. The tensile strength was improved with the new mediator
and laccase treatments. Besides, some impact on the fibre intrinsic
strength was observed. The laccase associated to the new mediator
allowed to enhance both breaking length and tear index.
On a Pine radiata unbleached kraft pulp, the laccase, alone or
associated to the new mediator, facilitated the refining. Breaking
length was enhanced at a given energy consumption. The fibres
were more amenable to the mechanical action and fibre fibrillation
and cutting requested less energy. This was confirmed by the higher
macrofibrillation index observed on the refined biotreated pulps.

Authors’ references:
1. InTechFibres – FCBA, BP 254, 38044 Grenoble, France; Phone: 04 76 76 10 10, Fax : 04 76 76 10 15
2. InTechFibres – CTP, BP 254, 38044 Grenoble, France
Autor correspondente / Corresponding author: Michael Lecourt – E-mail: michael.lecourt@fcba.fr

O PAPEL vol. 72, num. 8, pp. 57 - 61 AUG 2011