Surface Modification of Cellulose Acetate with Cutinase and ...

General Introduction: Application of Enzymes for Textile Fibres Processing
1983). Therefore, before cotton yarn or fabric can be dyed, it needs to be pretreated to
remove materials that inhibit dye binding. This step, named scouring, contributes to the
wettability improvement of fabric that can be then bleached and dyed successfully.
Highly alkaline chemicals such as sodium hydroxide were normally used for scouring.
These chemicals not only remove the impurities but also attack the cellulose, leading to
a reduction in strength and loss of fabric weight. Furthermore, the resulting wastewater
has a high COD (chemical oxygen demand), BOD (biological oxygen demand) and salt
content (Buschle-Diller et al., 1998). On the other hand, the enzymatic scouring,
bioscouring, leaves the cellulose structure almost intact, so it prevents cellulose weight
and strength loss. Bioscouring has a number of potential advantages over traditional
scouring. Bioscouring is performed at neutral pH which reduces total water
consumption, the treated yarn/fabrics retain their strength properties, the weight loss is
reduced or limited compared to processing in traditional ways and increases cotton
fibres softness. Several types of enzymes, including pectinases (Li and Hardin, 1997;
Karapinar and Sariisik, 2004; Tzanov et al., 2001; Choe et al., 2004; Ibrahim et al.,
2004), cellulases (Li and Hardin, 1997; Karapinar and Sariisik, 2004), proteases
(Karapinar and Sariisik, 2004), and lipases/cutinases, alone or combined, (Deganil et
al., 2002; Sangwatanaroj and Choonukulpong, 2003; Buchert et al., 2000; Hartzell and
Hsieh, 1998) have been studied for cotton bioscouring, pectinases seems to be the most
effective for that purpose.
Besides all the research done to develop an efficient bioscouring process, there is no
broad commercial application yet on industrial scale. There is still a demand for a
pectinase with higher activity and stability at hight temperatures and alkaline
conditions. A new bio-scouring pectate lyase from Bacillus pumilus BK2 was reported
by Klug-Santner and collaborators with optimum activity at pH 8.5 and around 70 ºC
(Klug-Santner et al., 2006). The new isolated pectate lyase was assessed for bioscouring
of cotton fabric. Removal of up to 80% of pectin was proven by means of
ruthenium red dyeing and HPAEC. Liquid porosimetry was used to evaluate the
increasing hydrophilicity of fabrics based on changes of the structural contact angle
(Bernard and Tyomkin, 1994). Using this methodology the authors found that, upon
enzyme treatment, hydrophilicity of the fabrics was dramatically enhanced (Klug-
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