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Enzymatic modifi cation of polyacrylonitrile and cellulose acetate fi bres 103

and Brenner 2001). Nitrile-degrading activity is found in three of the 21
plant families and in a limited number of fungal genera, whereas it is rela-
tively frequent in bacteria (Banerjee et al., 2002).
There is a group of nitrile-metabolizing enzymes that can convert the
nitrile groups into carboxylic or amide groups, depending on the type of
enzyme system. Figure 5.3 illustrates the possible chemical transformations
that may occur when treating copolymers of acrylonitrile with the various

R

N N N N N N n

O
H 2
2 H 2 O
Nitrilase Nitrile hydratase

NH 3

R R
HO O H 2 N O
N N N N n

H O
2
Amidase

NH 3

R R
HO O HO O
N N N N n

5.3 Possible chemical transformations on polyacrylonitrile surface
catalysed by nitrile-metabolizing enzymes.

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