Surface Modification of Cellulose Acetate with Cutinase and ...

1. Introduction
Enzymatic Hydolysis of Wool with a Genetically Modified Subtilisin E
The morphology of wool is highly complex, not only in the fibre stem but also on the
surface as well. It is in fact the surface morphology that plays an important role in the
wool processing. Unwanted effects such as shrinkage, felting and barrier of diffusion
are most probably due to the presence of wool scales on the fibre surface (Negri et al.,
1993).
Wool surface treatment with proteolytic enzymes seems to be a promissing alternative
to the traditional pollutant Chlorine/Hercosett process. However, enzymatic reaction
needs to be controlled, either by chemical or genetic modification, to avoid diffusion of
enzyme into wool cortex and consequent fibre damage (Silva et al., 2004; Silva et al.,
2005).
In contrast to chemical modification, the size and entire sequence of aminoacids of a
recombinant high molecular weight protein can be precisely controlled bythe DNA
coding sequence. In previous work developed by our group different cloning strategies
were used to increase subtilisin E molecular weight. Although the recombinant enzymes
were expressed, the soluble and active form of proteins was not achieved (Araújo et al.,
2008).
In this work we have used a protein based polymer to solubilize subtilisin E. A protein
polymer is a polypeptide chain composed of amino acids sequences, commonly found
in nature, which are arranged within a block or a set of blocks which are repeated in
tandem, producing a high molecular weight repetitive protein (Urry, 2006). This type of
polymers has been used for the solubilization and purification of hard proteins (Banki et
al., 2005, Trabbic-Carlson et al., 2004). Since this is a high molecular weight polymer
this may also function as an interesting possibility to functionalize subtilisin E for wool
finishing applications.
The present work compares the behaviour of two proteases, the commercial subtilisin,
Esperase, with low molecular weight, and a chimeric hight molecular weight subtilisin-
GAG220, in the diffusion and hydrolytic attack to wool fibres.
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