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Chitin, chitosan and bacterial cellulose for textiles 289

possibility of improving agricultural practices are signifi cantly limited. Thus,

by the middle of the 21st century, natural fibre production will be close to
exhaustion.

Besides the problem of limited natural sources, fibre production must be
environmentally clean. It is obvious that cellulose and other polysaccha-
rides, being from natural origin, are sustainable and healthy products, but
some of the processes required for their isolation and modifi cation present
serious pollution problems.
Over the past few years, a number of researchers have been involved in
investigating the exploitation of non-traditional sources of cellulose and in
designing biotechnological processes to produce this biopolymer. The pro-
duction of cellulose by micro-organisms is considered to be one of the most
promising ways to meet the environmental requirements. Apart from plants,
certain bacteria, algae (Koyama et al., 1997), and fungi (Morita et al., 2003)
also produce cellulose with an identical chemical composition to the cel-
lulose of plant origin.
In addition to cellulose, other polysaccharides such as chitin and chitosan
have also become widely used over the past few years, especially in the
chemical–pharmaceutical industry and in medicine. Chitin is the second
most abundant polysaccharide found on earth after cellulose and is the
main component in the shells of crustaceans, such as shrimp, crab, and
lobster and it is also found in exoskeletons of molluscs and insects and in
the cell walls of some fungi (Muzzarelli, 1994). The chitosan, usually pro-
duced commercially by alkaline deacetylation of chitin, is also found in
some fungi. Recent high interest in large-scale chitin and chitosan produc-
tion results from the need to process vast quantities of crab and shrimp
shell wastes from seafood companies. The recycling of these wastes is the
main commercial and sustainable way for large-scale chitin production.
The main objective of this chapter is to overview recent progress in pro-
duction and application of chitin, chitosan and bacterial cellulose fi bres.

12.2 Types of new fibres: chitin, chitosan and
bacterial cellulose

The natural polysaccharides chitin, chitosan and bacterial cellulose, although
sharing a similar structure, exhibit different properties that make them
useful for a large variety of applications.

12.2.1 Chitin structure and properties

Chitin, a polysaccharide (aminopolyglucan) composed of β(1–4)-linked
N-acetyl-d-glucosamine residues (Fig. 12.1a), occurs in exoskeletons, in the

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