Surface Modification of Cellulose Acetate with Cutinase and ...
Surface Modification of Cellulose Acetate with Cutinase and ...
Surface Modification of Cellulose Acetate with Cutinase and ...
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Subchapter 2.5<br />
Abstract<br />
The surface <strong>of</strong> commercial cellulose diacetate <strong>and</strong> triacetate fabrics was modified <strong>with</strong> a<br />
cutinase (EC 3.1.1.74). The enzymatic hydrolysis <strong>of</strong> acetyl groups on the fibre surface<br />
was evaluated by the release <strong>of</strong> acetic acid <strong>and</strong> by the specific chemical staining <strong>of</strong> the<br />
fabrics <strong>with</strong> the cotton reactive dye Remazol Brilliant Blue R. The fabric treatment,<br />
during 8 hours at 30 ºC <strong>and</strong> pH 8, led to an acetyl esterase activity <strong>of</strong> 0.17 nkat <strong>and</strong> 0.12<br />
nkat on cellulose diacetate <strong>and</strong> triacetate, respectively. The colour levels for samples<br />
treated <strong>with</strong> cutinase for 24 hours increased 25% for cellulose diacetate <strong>and</strong> 317% for<br />
cellulose triacetate, comparing to the control samples. Cross-sections <strong>of</strong> both fibres<br />
were analysed by fluorescence microscopy <strong>and</strong> confirmed the superficial action <strong>of</strong><br />
cutinase. Crystallinity <strong>of</strong> both fibres was slightly decreased as a result <strong>of</strong> the enzymatic<br />
treatment. For further improvement <strong>of</strong> cutinase catalysis, fusion cutinases at the Cterminal<br />
ends were produced <strong>with</strong> either the carbohydrate-binding module <strong>of</strong><br />
Cellobiohydrolase I, from the fungi Trichoderma reesei, or the carbohydrate-binding<br />
module <strong>of</strong> Endoglucanase C, from the bacteria Cellulomonas fimi. The knew<br />
recombinant cutinase fused to the fungal CBM was better than the bacterial one in<br />
improving the colour levels <strong>of</strong> treated fabrics, in particular for cellulose diacetate.<br />
In this work, evidences are provided showing that cutinase is a good c<strong>and</strong>idate for<br />
superficial regeneration <strong>of</strong> cellulose hydrophilicity <strong>and</strong> reactivity on highly substituted<br />
cellulose acetates, although further studies will be necessary to better characterize the<br />
nature <strong>of</strong> the fibre transformations induced by the modular cutinases.<br />
Nomenclature:<br />
C.I. - Colour Index<br />
CBH I - Cellobiohydrolase I <strong>of</strong> Trichoderma reesei<br />
CDA - <strong>Cellulose</strong> diacetate<br />
CenA - Endoglucanase A <strong>of</strong> Cellulomonas fimi<br />
CenC - Endoglucanase C <strong>of</strong> Cellulomonas fimi<br />
CTA - <strong>Cellulose</strong> triacetate<br />
DS - degree <strong>of</strong> substitution<br />
K/S - Kubelka-Munk relationship: K - adsorption coefficient, S - scattering coefficient<br />
o.w.f. - <strong>of</strong> weight <strong>of</strong> fabric<br />
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