Surface Modification of Cellulose Acetate with Cutinase and ...

Chapter 1
the yarn. The cellulase molecule binds to an exposed fibril on the surface of the yarn
and hydrolyses it in a process know as 'Bio-Stonewashing', leaving the interior part of
the cotton fibre intact. When the cellulases partly hydrolyse the surface of the fibre, the
indigo is partly removed and light areas are created. There are a number of cellulases
available, each with its own special properties. These can be used either alone or in
combination in order to obtain a specific look. Heikinhemo and collaborators
demonstrated that Trichoderma reesei endoglucanase II was very effective removing
color from denim, producing a good stonewashing effect with the lowest hydrolysis
level (Heikinheimo et al., 2000). Later Miettinen-Oinonen and collaborators developed
new genetically engineered T. reesei strains able to produce elevated amounts of
endoglucanase activity. Production of endoglucanase I and II was increased fourfold
above that of the host strain, without any production of cellobiohydrolases. Cellulase
preparations derived by the new T. reesei overproduction strains proved to be more
efficient for stonewashing process than the ones produced by parental strain (Miettinen-
Oinonen and Suominen, 2002). Application research in this area is mainly focused on
preventing or enhancing backstaining depending on the style required. Backstaining is
defined as the redeposition of released indigo onto the garments. Cavaco-Paulo and
collaborators were the first group studying in detail the nature of indigo-cellulase-
cellulose interactions (Cavaco-Paulo et al., 1998). These authors attribute the effect of
backstaining to the high affinity between indigo and cellulase and proved that the strong
ability of cellulase enzymes to bind to cotton cellulose is the major cause of
backstaining (Cavaco-Paulo et al., 1998). Later, the affinity of cellulases from different
fungal origins for insoluble indigo dye in the absence of cellulose was compared. The
authors reported that acid cellulases from T. reesei have higher affinity for indigo than
neutral cellulases of Humicola insolens (Campos et al., 2000). The same group studied
the interactions of cotton with CBD peptides from family I and family II and they
provided new highlights for tailoring cellulases when they found that truncated
cellulases without CBDs caused less backstaining than entire enzymes (Cavaco-Paulo et
al., 1999; Andreaus et al., 2000). These authors had previously studied the effect of
temperature on the cellulose binding ability of cellulases from T. reesei and the
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