Page 110 - Advances in Textile Biotechnology

Enzymatic hydrolysis and modifi cation of core polymer fi bres 91

niques in surface modification of PET and PA is that the favourable bulk
properties are not affected because the enzymes are too big to penetrate
into the bulk phase of the material.
Despite all the developments reported in this area, a better understand-
ing of the interactions between enzyme and substrates is required. Factors
such as protein adsorption, enzyme concentration, and level of agitation,
mass transfer and the role of hydrophobins or binding modules will infl u-
ence significantly the efficiency of hydrolysis. New strategies in terms of

protein engineering and bioinformatics can provide new tools that will
advance biocatalysis to a more competitive technology.

4.5 Conclusion and future trends

Despite some success already achieved, the potential benefits of biotechno-

logical modification of synthetic fibres are far from being fully explored.

The actual enzymatic modifications, described in this chapter, lead to the
creation of hydrophilic groups at the surface of cheap materials like PET

and PA. The new functionalized fibres can have a totally new range of

applications such as filter media and smart, technical and high-performance
materials. New methodologies have been developed to generate carboxylic,
amino and hydroxyl groups over PET and PA. Immobilization of enzymes
and other products such as chitosan at the surface of enzymatically modifi ed
fibres can be the future trends on this area.

Already, new enzymes with improved activity towards synthetic polymers
(Araújo et al., 2007) or better temperature stability have been produced
(Liu et al., 2008). Future challenges are in the area of thermostable enzymes
from extremophiles, molecular modelling, protein engineering and geneti-
cally modified enzymes. Novel strategies will need to be developed

based on chemoenzymatic approaches to locally functionalize synthetic
materials. Future trends will not only depend on enzyme technology but
also on the technology to apply the enzyme to the material. Soft-lithogra-
phy and inkjet technology allows application of chemicals and enzymes

locally in a controlled way. This will enable specific surface modifi cation and
functionalization.

4.6 Acknowledgements

V. A. Nierstrasz acknowledges support of the European Commission,
Marie Curie Grant, FP7-PEOPLE-2007-2-1-IEF, Grant Agreement Number
PIEF-GA-2008-219665, BIOTIC, Biotechnical functionalization of (bio)
polymeric textile surfaces. Carla Silva acknowledges support of the
Fundação para a Ciência e a Tecnologia, Grant SFRH/BPD/46515/2008.

© Woodhead Publishing Limited, 2010