Page 300 - Advances in Textile Biotechnology

Enzymatic functionalization of cellulosic fi bres for textiles 281

degraded (Lönnberg et al., 2006). This suggests that the XG, which can be
readily digested by endo-glucanases (endo-cellulases) (Gilbert et al., 2008;
Pauly et al., 1999b), acts as a selectively cleavable linker that can facilitate

recycling of grafted fibres in biocomposite materials. Indeed, existing tech-
nology involving the use of cellulases in paper and textile de-inking could
potentially be adapted for such an application (Soni et al., 2008; Zeyer
et al., 1994a; 1994b).

11.5 Conclusion and future trends
The use of XG as a molecular anchor to functionalize cellulose surfaces
holds considerable promise for the development of new materials. Building
upon a solid platform of knowledge of XG chemistry and enzymology,
biomimetic adaptation of the unique XG–cellulose interaction is opening
new possibilities for cellulosic substrates inherently derived from natural
sources. The ability of XG conjugates to bind to all types of cellulose, from

high-purity sources such as Whatman No. 1 filters (98% cotton cellulose,
mainly I α allomorph), cotton powder, bacterial and regenerated cellulose

to complex industrial wood pulp fibres, highlights the broad potential of the
system (Berry et al., 2001; Bodin et al., 2007a; Brumer et al., 2004; Zhou
et al., 2006a). Moreover, there is currently an unprecedented focus on the

use of cellulosic biofibres in diverse applications, from the nanoscale to the
macroscale, as a consequence of their unique strength-to-density ratio, bio-
degradability, and renewability (Dufresne, 2008; John and Thomas, 2008;
Mohanty et al., 2000; Pandey et al., 2005; Samir et al., 2005).
Continued development of biological and chemical methods to control
cellulose surface chemistry will be implicit in achieving the maximum per-
formance of cellulosic materials in individual applications. Simultaneous
with stepwise improvements in traditional commodities such as paper,
packaging, and textiles, revolutionary smaller-volume, higher value-added
products will be demonstrators of emerging technologies. In particular, the
use of cellulosic fibres in nanocomposites, biomedical applications, and

functional textiles has tremendous scope. Chemo-enzymatically modifi ed
XGs are thus a useful addition to the available toolkit necessary to realize
this potential. The application of these molecules to bast fibres, or in com-

bination with other types of enzymatic treatments (Mikolasch and Schauer,
2009), represent currently untapped areas that may bear fruit.

11.6 Sources of further information and advice

In the first instance, the reader is referred to the numerous articles and

reviews cited in the text, which have been selected as a starting point for
further exploration of the literature (the author regrets any omissions

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