Page 109 - Advances in Textile Biotechnology

90 Advances in textile biotechnology

fabrics. X-ray diffraction can also be used to study the polymer changes in
terms of crystallinity after enzymatic action (Silva et al., 2007a). The protein
adsorption is an important factor to take into consideration during enzy-
matic treatment. Several washes and controls with inhibited enzymes are
some of the techniques applied to eliminate the positive control attained
when high amount of protein is used.

4.3 Applications

The enhancement of the hydrophilicity of synthetic polymers such as
poly(ethylene terephthalate) and polyamide is a key requirement for many
applications ranging from electronics to functional and technical textiles.
The performance of PET can be improved by surface hydrolysis using
cutinases, the enzyme affects the surface properties not the favourable bulk

properties, especially when local modifications are required allowing spe-
cifi c functionalization. The functionalization of PET using fl uorescent mol-
ecules after cutinase treatment was recently demonstrated by Donelli et al.
(2009). Almansa et al. (2008b) increased the bonding strength of enzymati-

cally modified PET with polyvinyl chloride (PVC).
Polyamide performance can be improved by enzymatic hydrolysis result-
ing in an amine-enriched surface that can play an important role in proc-
esses such as the removal of heavy metal ions from aqueous solutions,
removal of dyes from wastewater, biofouling prevention, covalent immobi-
lization of proteins or coupling of flame retardants (Jia et al., 2006; Karimi

and Amirshahi, 2000). The immobilization of a laccase from Trametes hirsuta

onto an enzymatically modified nylon surface was reported by Silva et al.
(2007b). The immobilization would protect laccase from denaturation by
organic solvents and extend its half-life, at the same time allowing the
enzyme to be reused in several reaction cycles (Brandi et al., 2006;
D’Annibale et al., 2000; Durán et al., 2002).

4.4 Advantages and limitations

The strong focus on the search for new sustainable processes, makes bio-
catalysis with enzymes a valuable alternative to traditional chemical meth-
odologies, with advantages such as higher enantioselectivity, mild reaction
conditions and lower energy and equipment requirements. Enzymes have
proved to be environmentally friendly tools for hydrolysis of synthetic
polymers, with a pronounced effect at the surface of the polymer, without
compromising the favourable bulk properties of the polymer such as
strength and crystallinity. The strength of enzymatic surface modifi cation of
PET and PA is to increase hydrophilicity locally, allowing specifi c function-
alization and an important advantage of enzymes over conventional tech-

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