APPLICATION OF ENZYMES IN TEXTILE INDUSTRY
Mr. Edward Menezes Director
Rossari Biotech201-A & B , Ackruti Corporate Park,
LBS Marg, Next to GE Gardens,Kanjurmarg (W)Mumbai 400 078.
Telephone nos + 91-22- 25777604/05Fax+91-22-25796982
E-mail: [email protected]
The word Biotechnology is a cross between the Greek words
'bios' (everything to do with life) and 'techniques'
(involving human knowledge and skills). Biotechnology can
simply be defined as the application of living organism and
their components to industrial products and processes.
Biotechnology offers the potential for new industrial
processes that require less energy and are based on renewable
raw materials. Biotechnology makes use of biological systems
to manufacture products and provide services. The biological
systems that have traditionally been used are organisms such
as yeasts, fungi or bacteria. Thus, bio-tech can simply be
defined as the application of scientific and engineering
principles to the processing of materials by biological agents
to provide industrial products and processes, and an important
technology that will have a large impact on many different
industrial sectors in the future. It finds extensive
application in textiles and allied fields. The application of
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biotechnology to textile processing mainly consists of
application of enzymes to textile materials.
It is important to note that biotechnology is not just
concerned with biology, but it is a truly interdisciplinary
subject involving the integration of natural and engineering
sciences. Applications of biotechnology in textile wet
processing opens up a new horizon towards environmentally
friendly technology. Basic and applied research on microbial
cellulases, hemicellulases and pectinases has not only
generated significant scientific knowledge but has also
revealed their enormous potential in biotechnology.
Biotechnology has already lead to the development of new
products, opened new markets, speeded up production of pure
products and helped to reduce the pollution load. It also
offers the textile industry the ability
to reduce costs, protect the environment, addresses health and
safety and improve quality and functionality but the current
awareness of biotechnology is less. Therefore, the
applications are yet limited. Experience has shown that
whenever a clear economic justification and market for a
particular product or process exists, progress has been rapid.
So, it can be predicted that in the long term, more and more
of the cumbersome and polluting chemical procedures employed
by the textile industry will be substituted or supported by
the biotechnological processes.
Major applications of biotechnology in the textile industry
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Improvement of plant varieties used in the production
of textile fibres and in fibre properties.
Improvement of fibres derived from animals and health
care of the animals.
Novel fibres from biopolymers and genetically modified
micro-organisms
Replacement of harsh and energy demanding chemical
treatments by enzymes in textile processing
Environment friendly routes to textile auxiliaries
manufacturing such as dyestuffs
Novel uses of enzymes in textile finishing
Development of enzyme based detergents
New diagnostic tools for detection of adulteration and
Quality Control of textiles
Waste management
Following are the areas where biotechnology expected toplay an increasingly important role in the textile industryworldwide.
1. Fibres and Biopolymers Nature has provided us with textile fibres such as
Cotton, Wool, and Silk but there is now the potential to
harness biotechnology and produce new or modified fibres as
well as improve the production yields of existing fibres.
Cotton is still the world's leading textile fibre with some 20
million tons grown every year by about 80 producing countries.
However, cotton has the unfortunate characteristic of being
vulnerable to many insects, and to maintain yields, these
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insects are managed with large amounts of pesticides. Cotton
is also prone to infestation by weeds, which thrive under the
intense irrigation conditions that cotton needs throughout its
growth cycle, and cotton has poor tolerance to any of the
herbicides in use today. It is not surprising, therefore, that
biotechnology companies have focused their short-term
objectives on genetically engineering insect, disease, and
herbicide resistance into the cotton plant. Longer term goals
include the modification of fibre quality and properties (e.g.
length and strength) leading to the development of high
performance cottons.
In animal breeding and health care, biotechnology is
expected to have a large impact on animal fibre production
over the next few years. A whole range of new technologies are
now available including in vitro fertilisation and embryo
transfer, diagnostics, genetically engineered vaccines and
therapeutic drugs. Australia’s National Research Organisation
working on genetic modification of sheep to resist attack from
blowfly larvae by engineering a sheep that secretes an insect
repellent from its hair follicles and 'biological wool
shearing'. The latter technique relies on an artificial
epidermal growth factor which when injected into sheep
interrupts hair growth. A month later, breaks appear in the
wool fibre and the fleece can be pulled off whole in half the
time it takes to shear a sheep. There is also considerable
research being carried out in several countries with the aim
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of producing finer and therefore more valuable wool from
sheep.
Novel fibre-forming biopolymers are now being
manufactured using large-scale fermentation equipment. For
example, the bacterial storage compound polyhydroxybutyrate
(PHB) has been developed by Zeneca Bioproducts under the trade
name 'Biopol'. This high molecular weight linear polyester has
good thermoplastic properties (melting point 180°C) and can be
melt spun into fibres. Biocompatibility and biodegradability
makes PHB fibres ideally suited for surgical use; the body’s
enzymes slowly degrade sutures made from PHB. Zeneca is
currently using Biopol in conventional plastics applications
such as shampoo bottles.
Other biopolymers currently of particular interest in
wound-healing applications include the polysaccharides chitin,
alginate, dextran and hyaluronic acid. Chitin and its
derivative chitosan are important components of fungal cell
walls although these polymers are, at present manufactured
from seafood (shellfish) wastes. Patents by the Japanese
company Unitika cite the use of fibres made out of chitin in
wound dressings.
Dextran, is manufactured by the fermentation of sucrose
by Leuconostoc mesenteroides or related species of bacteria is
also being developed as a fibrous non-woven for speciality
end-uses such as wound dressings. Additional biopolymers, not
previously available on a large scale are now coming onto the
market thanks to biotechnology. One such example is hyaluronic
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acid a polydisaccharide of D-glucuronic acid and N-acetyl
glucosamine found in the connective tissue matrices of
vertebrates and is also present in the capsules of some
bacteria.
Two different biotechnological routes for the production
of cellulose are under investigation in various laboratories
throughout the world. Cellulose is produced as an
extracellular polysaccharide by a number of different bacteria
in the form of ribbon-like microfibrils. These can be used to
produce moulded materials of relatively high strength. Sony,
the Japanese electronics company has patented a way of making
hi-fi loudspeaker cones and diaphragms from bacterial
cellulose. An alternative route to cellulose, still at a very
early stage of development, concerns the in vitro cultivation
of plant cells. It has already been demonstrated that cotton
fibres can be produced in vitro by culturing cells of various
strains of Gossypium. The potential advantages of this route
include a more uniform product displaying particularly
desirable properties. Plant tissue culture can provide a
steady, all year supply of products without climatic or
geographic limitations free of contamination from pests.
Another group of biopolymers of particular interest to
biotechnologists are proteins because of the scope for
utilising the new genetic manipulation techniques. Thus genes
for animal and plant proteins (e.g. collagen, various silks)
can now be transferred into suitable microbial hosts and the
proteins produced by fermentation. The US army is keen to
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develop spider silk as a high performance fibre for use in
products such as bulletproof vests.
2. Enzymes Today, enzymes have become an integral part of the
textile processing. Though the use of enzymes in desizing was
established decades ago, only in recent years the applications
have widened with the introduction of new products. With the
increased awareness and regulation about the environment
concerns, the enzymes are the obvious choice. This is because
the enzymes are biodegradable, work under mild conditions and
save the precious energy. Enzymes, being biocatalyst and very
specific, are used in small quantities and have a direct
consequence of lesser packing material and lower
transportation impact. In an overall consideration, the
enzymes are the wonder products.
The preparation of certain textile fibres such as flax
and hemp by dew retting involves the action of pectolytic
enzymes from various microorganisms, which degrade pectin in
the middle lamella of these plant fibres. One enzyme that is
already being applied in textile processing for the removal of
hydrogen peroxide prior to dyeing is catalase.
There has been a dramatic increase in the use of enzymes
in detergents. Washing powders are referred to as ‘biological’
because they contain enzymes. Enzymes are now available that
can degrade a wide range of stains and their use allows milder
washing conditions at lower temperatures which both saves
energy and protects the fabric. Recently it was discovered
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that cellulase enzymes could replace the pumice stones used by
industry to produce 'stone-washed' denim garments. The stones
can damage the clothes, particularly the hems and waistbands,
and most manufacturers are now using the enzyme treatment.
Another novel application for cellulase enzymes is in
biopolishing, the removal of fuzz from the surface of
cellulosic fibres, which eliminates pilling making the fabrics
smoother and cleaner looking. A similar process using protease
enzymes has been developed for wool.
Enzyme Application Remarks
Amylase
Desizing of
woven cotton
and man-made
fabrics
Improving speed, economics and
consistency of the process, use of
thermostable enzyme, characterisation of
the process, are the developments in the
amylase applications.
Lipase DesizingTo remove triglyceride-based size
lubricants from fabrics.
Xylanas
e
Scouring and
bleaching
Pectins, waxes, colour, residual seed
coatings can be removed. These
substances, inhibit the natural
absorbency of the fibre and prevents
dyeing, printing or other finishing of
cotton yarns and fabrics. Earlier
scouring was done by caustic soda,
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removes desirable natural lubricants and
other materials, and causes serious
effluent disposal problem.
Catalas
e
To break down
residual
hydrogen
peroxide.
Reactive dyes are especially sensitive
to peroxides and currently require
extended rinsing and/or use of chemical
scavengers.
Pectina
seRetting of
flax
Rapid and controlled process is possible
with use of enzyme preparation and no
bacterial or fungal contamination occurs
like that in dew and water retting. Also
pre-treatment of flax with SO2 brings
about sufficient breakdown of woody
straw to speed-up enzyme action and
prevent bacterial and fungal
contamination.
Cellula
ses and
pectina
ses
Carbonization
Conventionally, vegetable matter in wool
is degraded by treatment with strong
acid and then subjected to mechanical
crushing. This can, in principle, be
replaced by selective enzyme degradation
of the impurities. Cellula
seBiostoning Uniform and quality finishing of fabric.
(100% use by Denim garment processors).
Earlier pumice stone was used to get
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characteristic abraded, faded
appearance.
Laccase Denim
finishing
This enzyme decolorises the indigo
dyestuff and enhances the apparent
abrasion effect with little or no impact
on cellulosic fibre strength.
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Cellula
se Biopolishing
To remove fine surface fuzz (protruding
fine fibres), surface pills (balls of
entangled fibres) and fibrils from
cotton and viscose fabrics. Treatment
gives cleaner, softer, smoother look and
feel.
Proteas
eWool
finishing
This is aimed at increased comfort
(reduced prickle, greater softness) as
well as improved surface appearance and
pilling performance.
Proteas
edegumming of
silk
To produce sand-washed effects on silk
garments. Treatment of silk-cellulosic
blends is claimed to produce some unique
effects. Proteases are also used to wash
down printing screens after use in order
to remove the proteinaceous gums, which
are used for thickening of printing
pastes.
Enzymes used in detergents
Enzyme Action
Protease Remove stains caused by proteins such as blood,grass, egg and human sweat
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Amylase Remove starch-based stains such as those made bypotatoes, pasta, rice and custard
Lipase Break down fats, oils and greases removing stainsbased on salad oils, butter, fat-based sauces andsoups, and certain cosmetics such as lipstick
Cellulase Brighten and soften the fabric, and releaseparticles of dirt trapped in the fibres
A. BIO-POLISHING:Commercial cellulases are mixtures of endoglucanses,
cellobio-hydrolases and Cellobiases. Endoglucanases attack
cellulose randomly and hydrolyze internal glycosidic bonds
whereas cellobiohydrolases remove terminal cellobiose residues
from both cellulase chain ends. Cellobiases hydrolyse small
cellobiose to glucose. This principle has allowed cellulase to
be used to modify the surface and properties of cellulosic
fibers and fabrics in order to an enzymatic removal of the
fuzz.
Biopolishing can be carried out any time during wet
processing, but it is most conveniently performed after
bleaching. The advantage of carrying out biopolishing at this
stage is that the fabric is clean, hydrophilic and more
accessible to the cellulases. If biopolishing is performed
after dyeing then there may be a risk of colour shade change,
any dyestuff may reduce the performance of enzyme so that a
higher concentration of enzyme would require.
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Recipe of Biopolishing Process:
Genecel HEBPL conc Liquid 0.3-0.8 %Time : 45-90 minutes.Temperature : 50 2 ºCpH : 4.5-5.5 (for acid stable cellulose)
ADVANTAGES OF ENZYMATIC BIO-POLISHING TREATMENT:
Enzymatic removal of the fuzz (bio-polishing) is
permanent and it not only keeps the fabric in good condition
after repeated washing but also enhances feel, colour,
drapeability, etc. and consequently the products fetch better
prices.
For bio-polishing of the cotton fabric, cellulase enzymes
are used which causes: (i) Prevention of the pills formation
(ii) Increased smoothness and softness (iii) Increased luster
and superior colour brightness (iv) Improved handle and
drapeability, and (v) Improved durable softness.
B. ENZYMATIC DESIZING:Alternative eco-friendly desizing agents are available in
the market in the form of enzymes. Complete removal of starch-
containing size without fiber damage is best obtained by using
enzymatic desizing agents. Formerly amylase derived from
pancreas or malt was used in desizing. Today liquid bacterial
amylase preparations dominate.
The enzymatic desizing process can be divided into three
stages:
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Impregnation: Enzyme solution is absorbed by the fabric. This
stage involves thorough wetting of fabric with enzyme
solution. During this stage, gelatinization of the size
(starch) is to the highest possible extent.
Incubation: The size is broken down by the enzyme. Long
incubation time allows a low enzyme concentration.
After-wash: The breakdown products from the size are
removed from the fabric. The desizing process is not finished
until the size breakdown products have been removed from the
fabric. This is best obtained by a subsequent detergent wash
(with NaOH) at the highest possible temperature.
ENZYMATIC DESIZING WITH AMYLASE:
The most popular method of removing starch from garments
is using amylase enzyme. Amylase breaks down the long starch
molecular chains into smaller fragments through
STARCH (insoluble) DEXTRIN (polysaccharides) MALTOSE
(disaccharides) GLUCOSE (monosaccharides - soluble) into
water-soluble or alkali soluble sugars. The degraded starches
are more soluble in alkali than in water. Hence an alkaline
wash after amylase based desizing is usually done.
Recipe for desizing with amylase:
Rexsize MHT 60 Powder 1.0-2.0 %Common salt 1.0-5.0 gms/lit
Kleenox PSF Liquid 0.5-1.0 gms/lit pH: 6.5-8.0 Temp. 60-65C
Time 30-90 mins
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It is important to follow the desizing with hot water
rinses. The cold-water rinse may re-solidify the unresolved
starch by enzymatic treatment and to redeposit it onto the
fabric surface.
C. ENZYMATIC SCOURING Scouring of textile material with enzymes is known as
Bio-Scouring. Bio-scouring is an enzymatic process, which can
be applied on any form cotton such as fiber, woven or knitted
fabrics and cotton blends. This process can be carried out on
various equipments such as jiggers, jets, pad batch, and pad-
steam range. The bio-scoured material can be used for
bleaching and dyeing. Suitable available enzymes for scouring
include protease, pectinase, hemicellulase and lipase. In
particular, pectinase can be used for scouring in the presence
of cellulase and lipase. The pretreatment with water is done
since wax and lipid compounds melt at temperature less than
100oC, exposure to water at 100oC should cause these compounds
to melt so as to disperse them into the pre-treatment water or
redistribute them over the fiber surface.
Recipe for exhaust method for bio scouring
Scourenz CBE New Powder 2.0 – 4.0 %H2O2 (50%) 3.0 %pH 10-11 Time 45 mins
Followed by hot wash and then cold wash.
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One bath enzymatic desizing / scouring / bleaching is
feasible when sufficient amyloglucosidase for glucose
production is present. Whiteness indices of the enzymatically
bleached goods are close to those fabrics bleached
conventionally with hydrogen peroxide. With lower costs and
less rinse water usage, the process presents an economically
interesting alternative for the textile preparation
industries.
D. PEROXIDE KILLERSAfter bleaching if the residual peroxide on the fabric is
not neutralised then it results in fabric tendering and
results in patchy dyeing. Conventional reducing agents used
for peroxide neutralisation are non-eco-friendly as they
increases the TDS of the effluent. Catalases on the other
hand catalyse the breakdown of hydrogen peroxide. Each
molecule of catalase being capable of processing around five
million molecules of hydrogen peroxide per second. Apart from
their specificity, high catalytic power and eco-friendliness
they does not interfere in dyeing and hence dyeing can be
continued in the same bath. Ultrox EPN 50 Liquid effectively
neutralises residual peroxide and hence avoids problems in
further processing
PEROXIDE NEUTRALISATION IN BATCH PROCESS
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At the end of peroxide bleaching, drain Rinse cold
Set the fresh bath at 45 – 55C and pH 6.0 – 7.0 with the Ultrox
EPN 50 Liquid 0.7–1.5 gms/lit Run the bath for 10-15 mins
Drain Adjust pH for required dye class and begin
dyeing in same bath
E. WOOL PROCESSINGTraditionally softening of coarser wool was carried out
using various chemicals such as silicones, dichloro
isocyanuric acid, tristearin and so on. now a days the
problem associated with the fuzz can be eliminated by removing
the fuzz using enzymatic treatment.
Enzymatic Softening of Wool
Load the material Add water Raise temperature
to 60ºC Adjust pH to 8.5 – 9.0
Add Zywet VPQ Liquid 0.5-1.0 gms/lit
Greasenz BSW Liquid 2.5 – 7.5 gms/lit
Run the machine for required time i.e. between 45 – 90 mins
Drain Rinse
Finish with
Zylon PLI Liquid 3 % o.w.f
At pH 5.0 – 5.5 and temp 50º C for 20 mins.
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It was observed the enzymatic treatment results in the
removal of the protruding fibers, which present on the surface
and gave a fuzzy appearance. During the enzymatic treatment,
the scales present on the surface were chemically modified and
due to this, a silky sheen is imparted to the surface of wool.
Thus, there ability to reflect light from their surface
increases, which improves luster of the wool after enzymatic
treatment. It results in the dissolution of the surface
fibers, which are stiff and coarser. Thus, smooth surface was
obtained after the enzymatic treatment and extra softness was
imparted. Since the enzyme dissolve the protruding surface
fibers completely the softening effect achieved is permanent.
F. DEGUMMING OF SILKThe raw silk thread consist about 70-80% fibroin and 20-
28 % of sericin. Sericin is chemically a non-filamentous
protein.
Set the bath with the following
Sodium Carbonate To adjust pH 8.5
Kleenon LXI Paste 2.0 – 3.0 gms/lit
Treat at 70C for 15 - 20 mins cool the bath to 600C
Add Silkenz DGM Liquid
5 – 10 gms/lit Run for 30 – 45 mins Drain two
hot washes at 900C for 15 mins each cold wash
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In silk sericin and fibroin both are proteins but due to
specificity of Silkenz DGM Liquid it only degrades sericin
without damaging fibroin, which is not possible otherwise with
conventional soda treatment. Hence, it improves degumming
efficiency, imparts soft feel and ensures maximum weight
reduction without affecting the fibre strength and hairiness.
G. POLYESTER PROCESSINGEnzymes in improving absorbency and wetting of polyester
fabrics:
The major draw back of alkaline hydrolysis includes
damage to fabric properties such as strength and caustic
discharge. Enzymes are protein molecules capable of catalyzing
specific chemical reaction of organic material. Hydrolyses are
capable of hydrolysing fatty acid or carboxylic ester, and in
principle, can hydrolyze the ester linkage in polyester.
Nowadays, a polyesterase enzyme with the polyester
article starting material under condition and for the time
suitable for the polyesterase to produce surface modification
and it disclosed a method for increasing the hydrophilicity of
a polyester to improve fabric characteristics such as stain
resistance, wettability, or a dyeability.
3. Textile Auxiliaries
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Textile auxiliaries such as dyes could be produced by
fermentation or from plants in the future. Many micro-
organisms produce pigments during their growth which are
substantive as indicated by the permanent staining that is
often associated with mildew growth on textiles and plastics.
Several of these microbial pigments have been shown to be
benzoquinone, naphthoquinone, anthraquinone, perinaphthenone
and benzofluoranthenequinone derivatives, resembling in some
instances the important group of vat dyes. Microorganisms
would therefore seem to offer great potential for the direct
production of novel textile dyes or dye intermediates by
controlled fermentation techniques replacing chemical
synthesis, which has inherent waste disposal problems e.g.
toxic heavy metal compounds.
Another biotechnological route for producing pigments
for use in the food, cosmetics, or textile industries is from
plant cell culture. One of the major success stories of plant
biotechnology so far has been the commercial production since
1983 in Japan of the red pigment shikonin, which has been
incorporated into a new range of cosmetics. Shikonin was
extracted from the roots of five year old plants of the
species Lithosperum erythrorhiz where it makes up about 1 to 2
percent of the dry weight of the roots. In tissue culture,
pigment yields of about 15 percent of the dry weight of the
root cells have been achieved.
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4. New Analytical Tools Research in biotechnology has already resulted in new
analytical methods for the textile industry. Work on molecular
biology has led to the development of species-specific DNA
probes for animal fibres. These probes can be used to detect
adulteration of high value speciality fibres such as cashmere
by much cheaper fibres e.g. wool and yak hair. Rapid methods
have been developed to assist in the early detection of
biodeterioration of textile and other materials. Studies show
that the presence of viable micro-organisms on textiles can be
assessed using the enzyme luciferase isolated from the firefly
(Photinus pyralis) which releases light (bioluminescence) in
combination with adenosine triphosphate produced by the micro-
organisms.
5. Waste Management
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Biotechnology can be used in new production processes
that are themselves less polluting than the traditional
processes and microbes or their enzymes are already being used
to degrade toxic wastes. Waste treatment is probably the
biggest industrial application of biotechnology. Specific
problems pertaining to the textile industry include colour
removal from dyehouse effluent, toxic heavy metal compounds
and pentachlorophenol used overseas as a rot-proofing
treatment of cotton fabrics. Currently much research is being
carried out to resolve these problems and biotechnology would
appear to offer the most effective solutions.
ConclusionToday, due to increasing awareness of environmental
concern, and important legislation on eco-toxicological
consideration issues such as health and safety during storage,
application and use, and safe disposal of chemical into
landfill and water or release in air during chemical
processing of textile is gaining importance.
So nowadays, with the increasingly important requirement
for textile manufacturers to reduce pollution in textile
production, the use of bio-enzymes in the chemical processing
of fibres and textiles is rapidly gaining wider recognition
because of their non-toxic and eco-friendly characteristics.
It is thus expected that in future, many of the
biotechnological processes would help in solving the
environmental problems posed by the textile industry.
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