PROCEDE DE MODIFICATION DE FIBRES POLYACRYLONITRILES CONTENANT VINYLACETATE EN TANT QUE COMONOMERE ET DE FIBRES POLYAMIDES AU MOYEN D'UNE ENZYME CUTINASE

METHOD FOR THE MODIFICATION OF POLYACRYLONITRILE FIBRES CONTAINING VINYL ACETATE AS A COMONOMER AND POLYAMIDE FIBRES, USING A CUTINASE ENZYME

Abrégé français

L'invention concerne un nouveau procédé enzymatique de modification de la surface de fibres synthétiques au moyen d'une enzyme cutinase (3.1.1.74). L'action enzymatique provoque l'hydrolyse des fibres polyacrylonitriles contenant vinylacétate en tant que comonomère, et de fibres polyamides, de manière à améliorer leurs caractéristiques hydrophiles et leurs propriétés de coloration.

Abrégé anglais

This invention relates a new enzymatic process for the modification of the
surface of synthetic fibres using a cutinase enzyme (3.1.1.74). The enzymatic
action causes the hydrolysis of the polyacrylonitrile fibres containing vinyl
acetate as a comonomer and polyamide fibres, improving their hydrophilic
characteristics and dyeing properties.

Revendications

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CLAIMS
1. Method for the treatment of
polyacrylonitrile fibre containing vinyl acetate as a
comonomer, characterised in that it comprises the contact
of the fibre with an enzyme solution in order to modify the
chemical surface of the fibre, increasing the number of
hydrophilic hydroxyl groups.
2. Method according to claim 1, characterised
in that it comprises the treatment of the polyacrylonitrile
fibre containing vinyl acetate as comonomer with an enzyme
with esterase action.
3. Method according to Claim 1, characterised
in that the enzyme contains the catalytic triad of serine-
histidine-aspartic acid.
4. Method according to claim 1, characterised in
that the enzyme esterase is a hydrolase that degrades
cutine.
5. Method according to claim 1, characterised by
the use of an amount of enzyme between 1 and 400 g of
protein per Kg of fibre.
6. Method for the treatment method of polyamide
fibre, characterised in that it comprises the contact of

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the fibre with an enzyme solution in order to modify the
chemical surface of the fibre, increasing the number of
hydrophilic amino groups.
7. Method according to claim 6, characterised in
that it comprises the treatment of the polyamide fibre with
an enzyme with esterase action.
8. Method according to claim 6, characterised in
that the enzyme contains the catalytic triad of serine-
histidine-aspartic acid.
9. Method according to claim 6, characterised in
that the enzyme esterase is a hydrolase that degrades
cutine.
10. Method according to claim 6, characterised by
the use of an amount of enzyme between 1 and 400 g of
protein per Kg of fibre.
11. Method according to claims 1 and 6,
characterised by the use of a treatment bath with a
retrievable and reusable enzyme.

Description

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DESCRIPTION
"METHOD FOR THE MODIFICATION OF POLYACRYLONITRILE FIBRES
CONTAINING VINYL ACETATE AS A COMONOMER AND POLYAMIDE
FIBRES, USING A CUTINASE ENZYME"
Field of the invention
The quality and the processing properties of
filaments in the extrusion line, fibres, yarns and textile
fabrics can be improved by modifying their surface. The
traditional processes used for their modification require
chemical agents with negative environmental effects. These
negative effects can be prevented by using new processing
techniques based on biotechnology.
Enzymatic processes can be used to modify the
surface of fabrics constituted by synthetic fibres.
Hydrolysis of polyacrylonitrile fibres containing vinyl
acetate as a comonomer and polyamide fibres results in the
formation of hydrophilic groups. The increase in these
groups at the surface of the fibres provides hydrophilic
characteristics, therefore improving the comfort
properties. This treatment also all ows these fibres to be
dyed with specific reactive dyes.

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Background of the invention
Cutinase 3.1.1.74 is an esterase which degrades
cutine, a structural polymeric component of plants composed.
of fatty acids (Carvalho et al., Biotech. Bioeng., 1999,
66, 17-34). This is an enzyme which is not very specific
and which hydrolyses soluble and non-soluble p-nitrophenyl
esters and triglycerides.
Several patents exist relating to the genetic
enhancement of Fusarium solani cutinases and their
application in the formulation of detergents for washing
machines and dishwashers. These products have shown better
lipolytiC action than other products previously used
(IN183592, EP1290150, AU1503800, AU5488090, US5512203,
W09414964, GB2296011, W08809367, EP0399681). In the textile
field, the use of cutinases to reduce baCkstaining during
stone-wash processes in cotton denim fabrics is also
described (CA2413838, US2002066144). Cutinase is also
described as being able to degrade aliphatic and aromatic
polyesters (US6255451).
Cutinase is an esterase which shares the
catalytic triad of serine-histidine-aspartic acid with
other esterases and amidases, meaning that the degradation
of amides besides ester groups is theoretically possible.
Recent research demonstrates that cutinase has activity in
more hydrophobic media due to the external amino acids in
the 3D structure (Vidinha et a1. (2003) "Effect of
immobilization support, water activity and enzyme

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ionization state on cutinase activity and
enantioselectivity in organic media", Biotechn. Bioeng.,
accepted).
The chemical agents of fibre modification
described in general do not restrict their action to the
fibre surface, rather they also penetrate inside and
degrade the fibres with deterioration of their properties.
One of the treatments that was normally carried out to
improve touch and increase the hydrophilicity of synthetic
fibres was alkaline treatment with high concentrations of
caustic soda. These treatments were damaging, not only to
the physical performance of the fibres but also to the
environment where the residues of this product were
deposited (US20030119172).
Several chemical methods have been used in order
to improve the structure of polyamide fibre. The
modification of this fibre, according to the method
described in the patent GB1072070, is carried out by
acylation of the peptidic groups as well as of the terminal
amino groups of the polyamide for greater polyamide
reactivity. Another method already described in the patent
US5599698 specifies the treatment of polyacrylonitrile
fibre Containing vinyl acetate as a comonomer with a nitryl
hydratase enzyme, in order to modify its hydrophilicity and
consequently its comfort properties, also allowing the
polyacrylonitrile fibres containing vinyl acetate as a
comonomer to be dyed with acid dyes.

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Detailed Description of the Invention
This invention describes the use of cutinase to
modify the surface of synthetic polyacrylonitrile fibres
containing vinyl acetate as a comonomer and polyamide
fibres. Superficial hydrolysis of the ester and amide
groups of the polyacrylonitrile fibres containing vinyl
acetate as a comonomer and polyamide fibres, respectively,
causes the formation of hydroxyl groups in the
polyacrylonitrile fibres containing vinyl acetate as a
comonomer and carboxylic and amino groups in the polyamide
fibres. The increase in these groups at the surface of the
fibres gives the fabric hydrophilic characteristics,
therefore improving the comfort properties. This treatment
also allows the polyacrylonitrile fibre containing vinyl
acetate as a comonomer to be dyed with reactive dyes (used
for cotton) and the polyamide fibre to be dyed with
reactive dyes (used for wool). To date, no method for the
modification of the vinyl acetate comonomer of acrylic or
polyamide has been described in scientific literature or
patents.
A first embodiment of the invention consists of a
method for the treatment of polyacrylonitrile fibre
containing vinyl acetate as a comonomer, which comprises
the contact of the fibre with an enzyme solution in order
to modify the chemical surface of the fibre, increasing the
number of hydrophilic hydroxyl groups.

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A second embodiment of the invention consists of
a method for the treatment of polyamide fibre, which
comprises the contact of the fibre with an enzyme solution
in order to modify the chemical surface of the fibre,
increasing the number of hydrophilic amino groups.
The treatment of the polyacrylonitrile fibre
containing vinyl acetate as a comonomer or the polyamide
fibre is preferably carried out using an enzyme with
esterase action.
The enzyme preferably Contains the catalytic
triad of serine-histidine-aspartic acid.
The abovementioned enzyme esterase is preferably
a hydrolase that degrades cutine.
The amount of enzyme used is normally between 1
and 400 g of protein per kg of fibre.
In both of the embodiments described above, a
treatment bath with a retrievable and reusable enzyme is
used.
Examples
The method consists of the chemical modification
of the surface of polyacrylonitrile fibres containing vinyl
acetate as a comonomer (constituted by about 93%

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acrylonitrile and 7% vinyl acetate) and polyamide fibres
through the action of a Cutinase solution obtained from the
heterologous expression of Fusarium solani p.isi cutinase,
by the Escherichia coli DHB4 transformed strain.
The treatment was carried out in a ROTAWASH
machine that simulates dyeings and other textile
treatments. Each container had between 1 and 2U (~.mol/min
as pNPP - paranitrophenolpalmitate) of cutinase activity.
Example 1:
Enzymatic modification of~lyacrylonitrile fibre
containing vinyl acetate as a comonomer
Samples of 0.7 g of polyacrylonitrile fabric
containing vinyl acetate as a Comonomer were washed with
water containing 1 g/L of Lutensol and dried at 50°C. The
samples were then placed in a container with 1 U of
cutinase, in a bath ratio of 1:35 (p/v). The treatment was
carried out at pH 7.5 and at 30°C, for a period of 700
hours. The samples were removed from the solution, washed
with water containing 2 g/L of Na2C03 and dried at room
temperature.
Hydrolysis was confirmed by the formation of
acetic acid arid the dyeing of the treated samples. No
acetic acid was detected in the treatment baths. The
samples were dyed with 2% reactive dye Remazol Brilliant

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Blue, using a bath ratio of 1:50 (p/v), at 70°C. In the
samples treated for 700 hours with the enzymatic solution
of cutinase, the value of K/S (spectral coefficient)
increased by an average of 30% in relation to the non
treated sample.
Example 2:
Enzymatic modification of polyamide fibre
Similar treatments were carried out to polyamide
fabric using the following parameters: fabric samples of
1 g were washed with water containing 1 g/L of Lutensol and
dried at 40°C. They were then placed in a specific
container in the ROTAWASH machine with 2 U of cutinase, in
a bath ratio of 1:200 (p/v). The treatment was carried out
at pH 8.5 at 30°C, for a period of 97 hours. The samples
were removed from the solution, washed with water
containing 2 g/L of Na2C03 and dried at 40°C. The
hydrolysis that occurred in the samples treated with the
enzymatic solution was verified through dyeing with a
reactive dye. The samples treated for 97 hours were dyed
with 2% reactive dye (Lanasol Red 66), obtained from CIBA,
using a bath ratio of 1:100, at 60 °C. In the samples
treated, the value of K/S (spectral coefficient) increased
in relation to the non-treated sample by 11.670 (60°C).