Surface Modification of Cellulose Acetate with Cutinase and ...

General Introduction: Application of Enzymes for Textile Fibres Processing
After weaving, the applied sizing agent and the natural non-cellulosic materials present
in the cotton must be removed in order to prepare the fabric for dyeing and finishing.
Before the discovery of amylases, this process (desizing) used to be carried out by
treating the fabric with chemicals such as acids, alkali or oxidising agents at high
temperatures. The chemical treatment was not totally effective in removing the starch
(which leads to imperfections in dyeing) and also resulted in a degradation of the cotton
fiber conducting to destruction of the natural, soft feel of the cotton.
Nowadays amylases are currently commercialized (MAPS, India) and preferred for
desizing due to their high efficiency and specific action. Amylases bring about complete
removal of the size without any harmful effects on the fabric (Etters and Annis, 1998;
Cegarra, 1996). The starch is randomly cleaved into water soluble dextrins that can be
then removed by washing. The utilization of harsh chemicals in the textile desizing was
substituted by amylases resulting in a lower discharge of waste chemicals to the
environment and improved the safety of working conditions for textile workers.
5. Pectinases
Pectin and other peptic substances are complex polysaccharides present in plant cell
wall as a part of middle lamella. Pectinolytic enzymes or pectinases are a complex
group of enzymes involved in the degradation of pectic substances. They are primarily
produced in nature by saprophytes and plant pathogens (bacteria and fungi) for
degradation of plant cell walls (Lang and Dörenberg, 2000; Bateman, 1966). There are
three major classes of pectin degrading enzymes: pectin esterases (PEs),
polygalacturonases (PGs) and polygalacturonate lyases (PGLs).
Pectin esterases are mainly produced in plants such as banana, citrus fruits and tomato
and also by bacteria and fungi (Hasunuma et al., 2003). Pectin esterase catalyzes
deesterification of the methyl group of pectin, forming pectic acid. The enzyme acts
preferentially on a methyl ester group of galacturonate unit next to a non-esterifed
galacturonate unit. The molecular weight of most microbial and plant PEs varies
between 30 – 50 kDa (Hadj-Taieb et al., 2002; Christensen et al., 2002). The optimum
pH for activity varies between 4.0 and 7.0. The exception is PE from Erwinia whose
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