Bio processing of textiles - Md. Rafsan Jany

Department of Textile Engineering
BIO-PROCESSING OF TEXTILES
(Bio-polishing & Enzyme washing)
A Dissertation submitted to the Department of Textile Engineering in partial fulfillment of
the credit requirement for achieving the Bachelor Degree in Textile Engineering by
Southeast University
By
2007200400024 Md. Rafsan Jany
Supervisor: Dr. Shah Mohammad Fatah-ur-Rahman
Associate Professor
September, 2011.

Department of Textile Engineering
A Dissertation submitted to the Department of Textile Engineering in partial
fulfillment of the credit requirement for achieving the Bachelor Degree in Textile
Engineering by Southeast University
By
2007200400024 Md. Rafsan Jany
Supervisor: Dr. Shah Mohammad Fatah-ur-Rahman
Associate Professor
September, 2011.

Table of Contents
Acknowledgement .............................................................. ……………………………………… 1-i
Abstract ........................................................................................................................................ 1-ii
Objectives ..................................................................................................................................... 1-iii
Limitation ..................................................................................................................................... 1-iii
Methodology................................................................................................................................. 1-iv
1 Introduction ........................................................................................................................... 1
2 Enzymes .................................................................................................................... ……… 2
3 The history of enzymes ......................................................................................................... . 3
3.1 The history of enzymes in Textile………………………………………………………... 4
4 Properties of the enzymes……………………………………………………………………... 5
5 General Characteristics of Enzymes……………………………………………………………. 6
6 Role of Bio-technology in Textile Processing………………………………………………….. 7
7 Role of Enzymes in Textile Processing………………………………………………………… 7
8 Mechanism of enzyme action…………………………………………………………………... 8
8.1 Model for Enzyme Action are Prepared Based on some Important Properties of Enzymes. 8
8.2 Model for Enzyme Action………………………………………………………………… 8
8.2.1 Lock and key model for enzyme action……………………………………………… 8
8.2.2 Induced fit model for enzyme action………………………………………………….. 9
8.3 How do enzymes work?........................................................................................................ 10
9 Factors affecting efficiency of enzymes………………………………………………………… 10
9.1 Temperature………………………………………………………………………………… 10
9.2 pH…………………………………………………………………………………………… 11
9.3 Concentration of Enzymes………………………………………………………………….. 11
9.4 Concentration of substrate………………………………………………………………….. 11
9.5 Concentration of products………………………………………………………………….. 12
9.6 Radiations…………………………………………………………………………………... 12
10 Classification of Enzymes…………………………………………………………………….. 12
11 Various enzyme used in textile processing……………………………………………………. 13
12 Enzymes for cellulosic textiles………………………………………………………………… 13
12.1 Amalyses……………………………………………………………………………………. 13
12.1.1 Thermo stable amylases……………………………………………………………….. 14
12.1.2 Conventional amylases………………………………………………………………… 14
12.1.3 Low temperature amylases…………………………………………………………….. 14
12.2 Cellulases…………………………………………………………………………………… 14
12.2.1 Acid Cellulases………………………………………………………………………… 14

12.2.2 Neutral Cellulases……………………………………………………………………… 15
12.2.3 Action of Cellulase…………………………………………………………………….. 15
12.3 Pectinases…………………………………………………………………………………… 15
12.4 Proteases……………………………………………………………………………………. 15
12.5 Peroxidases…………………………………………………………………………………. 15
12.6 Laccase……………………………………………………………………………………… 16
13 Trends in Bio-processing……………………………………………………………………… 16
13.1 Bio-catalysis………………………………………………………………………………… 16
13.2 Bio-singeing………………………………………………………………………………… 16
13.3 Bio-scouring………………………………………………………………………………… 16
13.3.1 Advantages of bio-scouring……………………………………………………………. 17
Differences between Conventional scouring & Bio-scouring…………………………………… 18
13.3.2 Integrated Bio- desizing and Bio-scouring…………………………………………….. 18
13.4 Bio-bleaching……………………………………………………………………………….. 19
13.5 Peroxide killers……………………………………………………………………………… 19
13.6 Enzymes effect on color…………………………………………………………………….. 21
13.7 Bio-carbonising……………………………………………………………………………… 21
13.8 Bio-polishing………………………………………………………………………………… 21
13.8.1 Bio-polishing of Knit fabric…………………………………………………………….. 22
13.8.2 Process Variables……………………………………………………………………….. 25
13.8.3 Results…………………………………………………………………………………... 25
13.8.4 Discussion………………………………………………………………………………. 30
13.8.5 Advantages of using enzymes for bio-polishing………………………………………… 31
13.8.6 Disadvantages of this finishing technique……………………………………………….. 31
13.8.7 Troubleshooting for bio-finishing……………………………………………………….. 31
13.9 Enzyme Wash (Denim)………………………………………………………………………. 32
13.9.1 Materials and methods…………………………………………………………………… 33
13.9.2 Results and discussions………………………………………………………………….. 35
13.9.3 Discussion……………………………………………………………………………….. 38
13.10 Textile Auxiliaries…………………………………………………………………………. 39
13.11 Enzymatic Decolorization…………………………………………………………………. 39
14 Enzyme Inactivation……………………………………………………………………………. 40
15 Why the industry owner should use Bio-technology in textile processing…………………….. 40
16 Conclusion……………………………………………………………………………………… 41

Acknowledgement
The department of Textile Engineering of Southeast University has given me the field to perform the project
with the ‘Bio-processing of Textiles’.
I am deeply indebted to my honorable supervising teacher specially Dr. Shah Mohammad Fatah-ur-
Rahman, Associate Professor and my entire course teacher of textile department as their rendered them
hand for all kind of help to me.
I would also like to thank Engr. Md. Faridul Hasan, Executive, Dyeing, Viyellatex Group Ltd. for helping
by giving me information about the project.
The encouragement as a continued source of inspiration provided by my parents is fully appreciated.
Finally I would like to acknowledge that I remain responsible for the inadequacies and errors, which
doubtlessly remain.
1-i

Abstract
Now a day’s the whole universe is concern about the hygiene and they are looking for eco-friendly
processes everywhere. Textile processing is responsible for polluting the environment at a large degree. Use
of Cellulase enzyme for denim washing is a standard eco-friendly technique to achieve desired appearance
and washing of denim and also the desired appearance of the knit fabric. Applications of enzymes to replace
harsh chemicals and other difficulties for the processing industries have been practiced for decades.
I have studied the bio-polishing effect of knit fabric & washing effect of denim fabric with Cellulase
enzyme under different condition.
1-ii

1-iii
Objectives
Bio-processing is becoming popular to enable companies to remain competitive and
profitable through the many benefits achieved by this concept.
The main objective of this project is to combine in a single volume the fundamental and
major applications of bio-processing which contributes eco friendly process, saving of cost,
saving of water uses, ensures the quality, so on by using bio-techniques.
 To know the effect of bio-polishing on knit fabric/garment.
 To know the effect of enzyme washing on denim fabric/garment.
 To find out the washing technique by which faded/old looks effect is created in the
garments.
Limitation
 It is based on knit fabric.
 All the experiment had done by cellulase enzyme.
 Focused on bio-polishing & enzyle wash only.

Methodology
Visited to different washing
Industries and knit dyeing
industries
Observed Different processes of
bio-polishing &enzyme washing
(cellulase enzyme)
Observed the effect of enzyme
on fabric and garments.
Group discussion done
Selected the suitable Process
and Recipe of Enzyme
application on Textile Processing
1-iv

Bio-processing of Textiles
1 Introduction
Bio-processing can simply be defined as the application of living organisms and
their components to industrial products and processes. It is not an industry in itself, but
an important technology that will have a large impact on many industrial sectors in
the future. Bio-processing is the application of biological organisms, systems or
processes to manufacturing industries. Bio-processing firms will rely mainly on
inexpensive substrates for biosynthesis, processes that will function at low temperatures,
and will consume little energy.
In Textile Processing the Enzymatic removal of starch sizes from woven fabrics has been in use
for most of this century and the fermentation vat is probably the oldest known
dyeing process. What has given Bio-processing a new impetus in the last few years
has been the very rapid developments in genetic manipulation techniques which introduces
the possibility of 'tailoring' organisms in order to optimize the production of established or
novel metabolites of commercial importance and of transferring genetic material from one
organism to another. Bio-processing also offers the potential for new industrial processes
that require less energy and are based on renewable raw materials.
Various applications which entail enzyme and colors broadly included fading of denim
and non-denim, bio- scouring, bio-polishing, silk degumming, carbonizing of wool,
peroxide removal, washing of reactive dyes, etc. incidentally enzymes were consumed to the
tune of about 70%in detergents than in textile industry.
1

2 Enzymes
Enzyme is a Greek word ‘Enzymos’ meaning ‘in the cell’ or ‘from the cell’. They are the
protein substances made up of more than 250 amino acids. Enzymes are high molecular weight
protein secreted by living organisms capable of catalyzing the chemical reactions of biological
process. Based on the medium for their preparation, they are classified as bacterial,
pancreatic (blood, lever etc) malt (germinated barely) etc. their major functions are fails
on hydrolysis, oxidation, reduction coagulation and decomposition. Grouped under the
following groups:
 Oxidoreductases – Oxidation, reduction reaction.
 Transferases – Transfer of functional groups.
 Hydrolases – Hydrolysis reaction.
 Lyases – Addition to double bond or its reverse
 Isomerases – Isomerisation
 Ligases – Formation of bonds with ATP clevages.
 Hydrolases type of enzyme is mostly used in textiles.
Enzymes are preferred in textiles due to the following reasons:
 Accelerate the rate of the reaction.
 Specific in action.
 Low temperature operation.
 Safe and control is easy.
 Replace harsh chemicals.
 No pollution.
 Biologically degradable.
2

3 The history of enzymes
The history of modern enzyme technology really began in 1874 when the Danish chemist
Christian Hansen produced the first specimen of rennet by extracting dried calves' stomachs
with saline solution. Apparently this was the first enzyme preparation of relatively high purity
used for industrial purposes.
This significant event had been preceded by a lengthy evolution. Enzymes have been used by
man throughout the ages, either in the form of vegetables rich in enzymes, or in the form of
microorganisms used for a variety of purposes, for instance in brewing processes, in baking, and
in the production of alcohol. It is generally known that enzymes were already used in the
production of cheese since old times.
Even though the action of enzymes has been recognised and enzymes have been used throughout
history, it was quite recently that their importance were realised. Enzymatic processes,
particularly fermentation, were the focus of numerous studies in the 19th century and many
valuable discoveries in this field were made. A particularly important experiment was the
isolation of the enzyme complex from malt by Payen and Persoz in 1833. This extract, like malt
itself, converts gelatinised starch into sugars, primarily into maltose, and was termed 'diastase'.
Development progressed during the following decades, particularly in the field of fermentation
where the achievements by Schwann, Liebig, Pasteur and Kuhne were of the greatest
importance. The dispute between Liebig and Pasteur concerning the fermentation process caused
much heated debate. Liebig claimed that fermentation resulted from chemical process and that
yeast was a nonviable substance continuously in the process of breaking down. Pasteur, on the
other hand, argued that fermentation did not occur unless viable organisms were present.
The dispute was finally settled in 1897, after the death of both adversaries, when the Buchner
brothers demonstrated that cell free yeast extract could convert glucose into ethanol and carbon
dioxide just like viable yeast cells. In other words, the conversion was not ascribable to yeast
cells as such, but to their nonviable enzymes.
In 1876, William Kuhne proposed that the name 'enzyme' be used as the new term to denote
phenomena previously known as 'unorganised ferments', that is, ferments isolated from the
viable organisms in which they were formed. The word itself means 'in yeast' and is derived from
the Greek 'en' meaning 'in', and 'zyme' meaning 'yeast' or 'leaven'.
In 1894, Dr. Jokichi Takamine filed patent applications for Taka koji from Aspergillus oryzae.
This is the fungus used in making sake.
In the early 1900’s, John Beard experimented with juices extracted from animal pancreases and
the effects on cancer tumors.
In 1926, Dr. James B. Sumner determined that enzymes are proteins. From 1932 to 1942, Dr.
Francis Pottenger conducted experiments on the effects of cooked foods fed to cats. They were
compared to cats fed raw food only. The cats fed the cooked foods developed diseases such as
arthritis and diabetes. He concluded the raw foods contained some substance, which was
destroyed by cooking, and this substance had nutritional benefit.
3

In 1940, Dr. Edward Howell began investigating the connection of chronic degenerative disease
and severe enzyme deficiency. He wrote two books: Enzyme Nutrition and Food Enzymes for
Health and Longevity.
In the 1930’s and 1940’s, Dr. Max Gerson discovered the importance of organically grown
whole foods. He found raw fruits and vegetables were the healthiest and concluded that 80% of
all disease could be extinguished by eliminating canned, frozen and processed foods from the
diet.
In 1963, William Kelley D.D.S. rediscovered the connection between pancreatic enzymes and
cancer remission.
4
3.1 The history of enzymes in Textile
 Amylase Desizing(1952).
 Protease Wool (1984).
 Cellulase Bio-stoning (1987).
 Catalase Bleach cleanup (1993).
 Laccase Denim Bleaching (1996).
 Peroxidase Enzymatic Rinse (1999).
 Pectate Lyase Bio-scouring (2003).

4 Properties of the enzymes
Enzymes are proteins that catalyze or increase the rate of a chemical reaction. They show
following properties -
Specificity –
 Each enzyme can catalyze the change of either a specific substrate or a specific group of
5
substrate.
 The specificity for a substrate can easily be demonstrated.
Optimum Temperature –
 Enzymes generally function in a particular range of temperature which usually
corresponds to the body temperature of the organism.
 Each enzyme shows its peak activity at a specific temperature called the Optimum
temperature.
 Activity declines both above and below the optimum temperature.
 Low temperature preserves the enzyme in a temporarily inactive state.
 High temperature destroys enzyme activity, because proteins are denatured by heat.
 For this reason, only a few cells can tolerate temperatures above 45 degrees centigrade.
 Some heat resistant microorganisms living in hot springs at temperatures close to 100
degrees centigrade possess heat resistant enzymes.
Optimum pH –
 Each enzyme shows its highest activity at a specific pH. This pH is called Optimum pH.
 Activity declines both above and below the optimum pH.
 Most intracellular enzymes function best near neutral pH.

5 General Characteristics of Enzymes
 An enzyme lowers/ reduces the activation energy required to carry out the reaction.
 Enzymes themselves do not undergo any change, means they remain intact at the end of
6
reaction.
 Enzymes are highly specific for their substrates.
 Enzymes are present in very less amount in body and have specific life span.
 Activators are the molecules that enhance the enzyme activity.
 Inhibitors are the molecules that reduce the enzyme activity.
Activity of enzymes depends upon:
 Concentration of specific enzymes
 Concentration of its substrate
 pH of reaction
 Temperature of reaction
 Concentration of salts
 Presence of activator or inhibitor
 Time required to carry out the reaction
 Presence of proteolytic enzymes.

6 Role of Bio-technology in Textile Processing
The major areas of applications of biotechnology in textile industry are,
 Improvement of plant varieties used in production of textile fibres and in fibres and in
7
fibre properties.
 Improvement of fibres derived from animals and health care of animals
 Novel fibres from biopolymers and genetically modified microorganisms
 Replacement of harsh and energy demanding chemical treatments by Environment
friendly routes to textile auxiliaries such as dyestuffs
 Novel uses for enzymes in textile finishing
 Development of low energy enzyme based detergents
 New diagnostic tools for detection for adulteration and quality control of textiles
 Waste managements
7 Role of Enzymes in Textile Processing
Enzymes are large protein molecules made up of long chain amino acids which are produced by
living cells in plants, animals and microorganism such as bacteria of fungi. Enzymes are
secretions of living organisms, which catalyze biochemical reactions. Enzymes are biocatalysts
without which no life in plant or animal kingdom can be sustained. Today enzymes have become
an integral part of the textile processing. Though enzyme in desizing application was established
decades ago, only in recent years the application has widened with new products introduced.
With the increase in awareness and regulation about environment concerns, enzymes are the
obvious choice because enzymes are biodegradable and they work under mild conditions saving
the precious energy. Enzymes being biocatalysts and very specific are used in small amounts and
have a direct consequence of lesser packing material used, the transportation impact is lower. In
an overall consideration enzymes are the wonder products.
Salient features of enzyme application in textile process are
 Extremely specific nature of reactions involved, with practically no side effects.
 Low energy requirements, mild conditions of use, safe to handle, non- corrosive in their
applications.
 On account of lesser quantities of chemicals used in process as well as ease of
biodegradability of enzymes results in reduced loads on ETP plants.
 Enzymes under unfavorable conditions of pH or temperatures chemically remain in same
form but their physical configuration may get altered i.e. they get “denatured” and lose
their activity. For this reason live steam must never be injected in a bath containing
enzymes and any addition of chemicals to the enzymes bath must be done in pre-diluted
form.
 Compatibility with ionic surfactants is limited and must be checked before use. Nonionic
wetting agents with appropriate cloud points must be selected for high working efficiency
as well as for uniformity of end results.
 High sensitivity to pH, heavy metal contaminations and also to effective temperature
range. Intense cautions are required in use.

8 Mechanism of enzyme action
Enzymes are complex biochemical catalysts, speeding up a particular reaction to produce an
ordered, stable reaction system in which the products of any reaction are made when they are
needed. A specific enzyme controls each reaction in a series of metabolic reactions. Enzymes
also control cell metabolism by regulating how and when reactions occur.
They are made up of globular proteins that have complex tertiary or quaternary structure.
Enzyme shape is maintained by hydrogen bonds and ionic forces and their function can be
affected by changes in temperature and pH.
8.1 Model for Enzyme Action are Prepared Based on some Important Properties of
8
Enzymes.
 Each enzyme is specific and catalyzes only one reaction at a time
 Enzymes combine with their substrates to form temporary enzyme-substrate complex.
 Enzymes are not altered or used up in the reactions they catalyze, so can be used again
and again.
 Enzyme catalyzed reactions are sensitive to temperature and pH.
 Enzyme catalyzed reactions can be slowed down or stopped by inhibitors.
 Enzymes lower the activation energy of a reaction thus making the reaction to occur very
rapidly with large turnover numbers.
8.2 Model for Enzyme Action
There are two models proposed for enzyme action. They are as follows:
8.2.1 Lock and key model for enzyme action
It was proposed by Emil Fischer. Lock and key model states that a substrate fits into the enzyme
in a similar way as a key fits into a specific lock. The active site is a particular shape (the lock)
into which only one substrate (the key) will fit. The substrate fits the active site because it is a
complementary shape and because the chemical charges attract each other (amino acids at active
site are charged). The enzyme and substrate combine for an instant to form an enzyme substrate
complex. The formation of this complex brings about the desired chemical reaction, converting
substrate into products.

Figure 1-Lock & key model of enzyme specificity
Figure 2-Active site of enzyme blocked by poison molecule
8.2.2 Induced fit model for enzyme action
It was proposed by Daniel Koshland. This model suggests that the active site in many enzymes
is not exactly the same shape as the substrate, but moulds itself around the substrate as the
enzyme substrate complex is formed. Before substrate binding the active site of the enzyme is
relaxed. When the substrate binds the active site is pulled into correct shape by molecular
interactions between the two molecules and enzyme- substrate complex forms. As the products
fall away from the active site, the molecule becomes relaxed again
Figure 3-Induced fit model
9

8.3 How do enzymes work?
Enzymes are thought to have an area with a very particular shape. When a molecule of the right
chemical for that enzyme comes along it will fit exactly into the shape. The area of particular
shape is called the active site of the enzyme, as that is where the reaction takes place. The
molecule that the enzyme works on is called the substrate. After the reaction has taken place
and the products of the reaction leave the active site leaving it ready for another molecule of the
chemical.
The active site of an enzyme has such a particular shape that only one kind of molecule will fit it,
rather like a particular key fitting a lock. This is why enzymes are specific in their action.
9 Factors affecting efficiency of enzymes
10
9.1 Temperature
 Enzymes work at particular temperature. Change in temperature alters their
efficiency. Most of enzymes work at 40-6000C.
 Above optimum temperature, heat alters the shape of enzyme molecule, changing
the shape of active site. This leads to reduction in their activity.

Figure 4-Working of enzyme

11
9.2 pH
 Some enzymes work best in alkaline medium, while some work best in acidic
medium for every enzyme there is optimum pH where its activity is highest.
9.3 Concentration of Enzymes
 Increase in concentration of enzymes increases the reaction rate.
9.4 Concentration of substrate
 Increase in concentration of substrate increases the reaction rate till certain point.

12
9.5 Concentration of products
 Accumulation of products decreases the enzyme activity.
9.6 Radiations
 Exposure to UV rays, X-rays reduces their reactivity.
10 Classification of Enzymes
 Oxido Reductases:
These enzymes catalyze oxidation-reduction reactions involving transfer of atom or electrons.
 Transferases:
These enzymes transfer C, N, P or S containing groups from one substrate to another.
 Hydrolases:
These enzymes catalyze cleavage reaction by hydrolysis.
 Lyases:
They non-hydraulically remove group from the substrate with formation of double bond or add
new groups across double bond to convert it into single bond.
 Isomerases:
These enzymes catalyze intermolecular rearrangements to form an isomer. (Isomer –Same
molecular formation but different structural formula)
 Ligases:
These split C-C, C-O, C-N, C-S or C-halogen bonds without hydrolysis or oxidation.

11 Various enzyme used in textile processing
Type Action
Amylases To decomposes starches in sizing preparation
Catalases Act on hydrogen-peroxide to decompose it into
12 Enzymes for cellulosic textiles
12.1 Amalyses
Amylases are hydrolase class of enzymes, which hydrolyses 1-4 α glucosidic linkage of amylase
and amylopectin of starch to convert them into soluble dextrins. Among the different classes of
commercially available amylases, some important industrial enzymes for textile and their sources
are given below.
Animal Enzymes
Enzyme Source
Catalase Liver
Lipase Pancreas
Protease Pancreas
Bacterial Enzyme
-amylase Bacillus
Protease Bacillus
Plant Enzyme
Protease Carica papaya
13
water & oxygen
Proteases When combines, act on proteins, pectins &
natural waxes to effect scouring
Laccases Decompose indigo molecules for wash-down
effect on denim
Cellulases
Break down cellulosic chain to remove
protruding fibres by degradation & wash-down
effect by surface etching on denim etc.

FUNGAL ENZYMES
α-amylase Aspergillus
Catalase Aspergillus
Cellulase
14
Trichoderma
Trameters
Hirsuta
Laccase Phlebia radiate
Lipase Rhizopus
Aspergillus
Pectinase Monilinia
Fructigena
Protease Aspergillus
The following types find major application in textiles.
12.1.1 Thermo stable amylases
Amylases which catalyse starch hydrolysis in the temperature range of 70-1100C and at pH 6.0-
6.8.
12.1.2 Conventional amylases
Amylases which catalyse starch hydrolysis in the temperature range of 50-700C and at pH 6.0-
6.8.
12.1.3 Low temperature amylases
Majority of fungal amylases which catalyze starch and hydrolysis in the temperature range of 30-
700C and at pH 6.0-6.8.
12.2 Cellulases
Cellulases are hydrolase class of enzymes which cleavage 1-4β glucosidic linkage of cellobiose
chain or cellulose. The commercially available cellulases are a mixture of enzymes viz.,
Endogluconases, Exogluconases and Cellobiases, Endogluconases are subclass of celluase
enzymes which randomly attack the cellulose enzymes and hyudrolyze the 1-4 β glucosidic
linkage of cellobiose chain. Exoglucanases of cello-biohydrolases are again subclass of cellulose
enzyme which hydrolyses 1-4 β glucosidic linkage of cellulose to release cellotiose from the
cellulose chain and Cellobiases are enzymes whichhydrolyse cellobiose into soluble glucose
units. All these three enzymes act synergistically on cellulose to hydrolse them. Among the
different classes of commercially available cellulases, following types find major application in
textiles.
12.2.1 Acid Cellulases
Acid cellulases are class of enzymes that act at pH 3.8-5.8 (-optimum 4.5-6) and in the
tempereature range of 30-600C. The low temperature range is of 30-600C and conventional acid
cellulases act in the temperature range of 45-600C.

Figure 5-Cellulase enzyme
15
12.2.2 Neutral Cellulases
Cellulase enzymes which actr at pH 6.0-7.0 and in the temperature range of 40-550C are termed
as neutral Cellulases.
12.2.3 Action of Cellulase
Enzymes are large molecular complex and can’t penetrate interior of the fabric. Hence enzyme
action takes place preferentially on the surface. Where cleavage of cellulose chain occurs,
Microfibrils which are loose fibres break off under the influence of bio-catalytic degradation and
results in better mechanism or modify the surface of the fabric.
Enzymes contain activity centre in three dimensional structure form namely fissures, holes,
pockets, cavities, hollows.
These enzymes first of all form an enzyme substance complex on the surface of the cellulose.
Bio-reaction then takes place in the above mentioned substrate mentioned enzyme substrate
complex.
Finally, the complex disintegrates with the release of the reaction products and the original
enzymes which are once again available.
12.3 Pectinases
Pectinases are a mixture of enzymes, which along with other such as cellulose, are widely used
in the fruit juice industry. Enzymes in this pectinase group include polygalacturonases, pectin
methyl esterase and pectin lyases. These pectinase enzymes act in defferent ways on the pecans,
which are found in the primary cell walls of cotton and jute. Pectins are large polysaccharide
molecules, made up of chains of galacturonic acid residues.
12.4 Proteases
Proteases are Hydlolase class of enzymes, classified based on the source from which it is
extracted, optimum temperature of activity. Proteases precisely act on peptide bonds formed by
specific amino acids to hydrolyze them. Commercial proteases are available, which can work in
different range of pH and temperature. Trypsin (pancreatic), Papain based and alkaline proteases
find industrial applications in textiles.
12.5 Peroxidases
Peroxidases or Catalases are Oxidoreductase class of enzymes. The perosidase enzyme catalyse
the decomposition of hydrogen peroxide in to water and molecular oxygen as illustrate.
2 H2O2→2 H2O + O2
Catalase is a heam-contaioning enzyme. Thus, in addition to the protein part of the molecule the
enzyme contains a non-protein part, which is a derivative of heam and includes the metal iron.

Peroxidases effectively degrade the hydrogen peroxide at varied pH between 3 to 9 and in the
temperature range 30 -800C.
12.6 Laccase
Laccases are Oxidoreductase class of enzymes, belonging to bluoxidase- copper
metalloenzymes. Lassases are generally active at pH 3-5 and in the optimal temperature range of
30-500C. They oxidize using molecular oxygen as electron acceptor from the substrate. Their
special property of oxidation of indigo pigments is made use of in textile industries.
16
13 Trends in Bio-processing
13.1 Bio-catalysis
Owing to the specific nature, enzymes have become an important class of bio-chemicals in
textile processing. Being bio-catalysts, enzymes were not consumed in the reaction. They were
also used in the processing from a standing bath. Illustrating a schematic diagram for working of
an enzyme, he indicated the active and secondary sites and how the enzyme was larger than the
substrate as it attached itself to cellulose forming a complex in which the concentration of the
reactants increased thousands times due to which the reaction proceeded. The substrate was
broken into degradation products making the enzyme available to attach itself again to another
substrate and the cycle was repeated and thereby the enzyme became a biocatalyst.
13.2 Bio-singeing
This mode of finishing has been specifically developed to achieve clearer pile on terry towel
goods. A treatment with an enzyme, which is a powerful cellulase composition, gives clearer
look to the pile, improves absorbency and softness.
Earlier, desizing was carried out by steeping the fabric with mineral acid, which affected the
cellulose as well as the colour. Use of enzymes here led to reaction with the starch only and thus
they assumed considerable significance. Explaining the action of enzymes, the food consumed
by human body was digested due to secretion of the enzyme. At the enzyme-substrate complex
level, the concentration of the reactants became large and accelerated the reaction while reducing
the activation energy barrier. Thus, the reaction which took place at higher temperature and
severe conditions could be carried out at relatively lower temperatures and milder conditions.
13.3 Bio-scouring
Bio scouring did not involve any colour, yet after scouring the fabric was dyed with colours.
Cotton could be treated with bio-scouring enzyme although the techno-economical parameters
were not conductive. But, it had a bright future due to rigorous effluent treatment since disposal
of both caustic soda and soda ash was causing environmental concern. The enzymes helped

removal of waxes, pectins, sizes and other impurities on the surface of the fabric. Combination of
pectinase and lipase gave best results, but cost of the latter was a deterrent.
Advantages of bio-scouring were lower BOD, COD, TDS, and the alkaline media of water,
extent of cotton weight loss, which was a boon to the knitting industry, lower alteration of cotton
morphology i.e. less damage since it was specific to pectin and waxes and not cellulose besides
increased softness. The lone disadvantage was that the cotton motes were not removed, which
warranted peroxide bleaching.
Traditionally, cotton scouring has required the use of harsh alkaline chemicals (caustic), extreme
temperatures water. Expenses include not only the cost of the caustic and energy, but also the
cost of treating wastewater to caustic and by-products.
Today, textile producers have a new, effective alternative to chemical scouring with the advent
of the Cottonas novel enzyme not only cleans better than chemical scouring. But also greatly
reduces the need for extensive and energy consumption. The Cottonase T enzyme is a
versatile, economically viable and environmentally friendly chemical scouring in cotton
preparation. Noncellulosic impurities, such as fats, waxes, proteins, pectins, natural and
water-soluble compounds, are found to a large extent in the primary wall and to a lesser
extent in the secondary 3) and strongly limit the water absorbency and whiteness of the
cotton fiber. Quantity and composition varies v present serious problems as they are
basically undyeable.
The bio scouring process is built on –
 Protease
 Pectinase
 Lipase enzymes act on proteins & natural waxes to effect scouring of cotton.
13.3.1 Advantages of bio scouring
 Milder conditions of processing, low consumption of utilities, yet excellent absorbency in
17
goods.
 No oxy-cellulose formation and less strength loss because of absence of heavy alkali in
bath.
 Uniform removal of waxes results in better levelness in dyeing.
 Highly suitable for scouring of blends containing fibres like silk, wool, viscose,
modal, lyocell, lycra etc.
 Low TDS in discharge.
 Fabric is softer and fluffier than conventional scouring. Ideal for terry towel/ knitted
goods.

Differences between Conventional scouring & Bio-scouring
Conventional scouring Bio-scouring
18
Process carried at high temperature and
pressure for 4-6 hours
Process carried at ambient temperature and
pressure
Process is energy intensive Low energy process
Residual alkali in effluent is high Residual alkali in effluent is negligible
Water consumption in the process is high Water consumption in the process is low
Fabric quality attributes:
Parameter Conventional scouring Bio-scouring
Fabric weight loss (%) 13 12
Water absorbency(seconds) Instantaneous 3
Whiteness index 70 67
Fluidity 2.2
6.8*
2.3
2.9*
Color strength(K/S) 10 11
Strength retention (%) 77.4 82.5
*Scoured & bleached.
Source- Central Institute for Research on Cotton Technology, India.
13.3.2 Integrated Bio- desizing and Bio-scouring
The integrated Bio-desizing and Bio-scouring system uses an empirically developed enzyme
formulation, based on amylase, pectinase, protease and lipase that act synergistically, resulting in
desizing and scouring of cotton goods, under mild conditions.

19
Material Enzyme based
speciality
Wetting
agent Remarks
Yarn Ecoscour Unopol AW Excellent absorbency
in 55-60 minutes
Knits Ecoscour Unozin SD
Specific wetting agent
for Mineral oil
contaminants.
Desized
woven Ecoscour Unozin SD Applicable by pad or
Exhaust methods.
Grey woven Ecoscour DS Unozin SD
Single stage desizing
and scouring by pad or
exhaust
13.4 Bio-bleaching
It was applicable for all kinds of colours and a single enzyme could be used in the textile
industry. Bio-bleaching had been adapted for denim. Indigo specific lipases were used to bleach
indigo. Earlier denim was bleached with chlorine to get lighter denim or wash down effect.
Lipase combination was used successfully and if this could be extended to other colours, this
would become an important enzyme in future. The advantages were environment friendly
application, non AOX generation and cellulose was not affected. A bio-bleaching or lipase
treatment on denim gave an authentic wash resulting in an excellent look, which was better than
a neutral wash and a grey cast, which was used in bleaching.
Amylase and lipase were used for desizing and cellulase for aberration. Lactase was introduced
for bleaching of indigo.
13.5 Peroxide killers
It ensured shade quality particularly with reactive dyes, reduced the complexity of treatment after
peroxide bleaching and conserved water. In case of reactive dyeing, after bleaching it was vital
that the peroxide residues must be cleared out of the system and as such there were no fool proof
ways of such clearance, which entailed several rinsing operations or reduction treatments.
Empirically, it was difficult to know how much quantity of reducing agent was required to react
with the peroxide left in the bath. In the event either of them happened to be excess, it might
affect the dyeing. Therefore, after bleaching, the bath should be neutralized with peroxide killers
like peroxidase or catalase followed dyeing with reactive dyes. They did not affect reactive dyes
and only react with the peroxide. These catalysts were fastest acting type as 1 molecule of
catalyst destroyed 5 million molecules of peroxide or 700 times its own weight of peroxide.
Catalase for Bleach Clean-up – Saving water and energy
Fabrics are often bleached with hydrogen peroxide prior to dyeing and finishing. Residual
hydrogen peroxide must be removed to obtain the most efficient dyeing. Repeated water washes

or chemical reducing agents have traditionally been used, and now it is common practice to
apply catalase enzymes which decompose hydrogen peroxide to oxygen and water. Significant
process savings are possible because the treatment is fast, mild, and dyeing can be carried out in
the same liquor and equipment as the catalase treatment.
Time Water Steam Power Catalase Acid Total
20
Efficiency of H2O2 removal
Conventional process Enzymatic process
Process Residual
peroxide, ppm Process Residual
peroxide, ppm
After bleaching 100 After bleaching 100
After the 1st hot rinse 60 Catalase, 5 min 10
After the 2nd hot rinse 10 Catalase, 10 min 2
After the 1st cold rinse 2 Catalase, 15 min 0.5
Before dyeing 0.5 Catalase, 20 min 0
Cost saving:
*(1000 kg of fabric, liquid ratio 10:1.Cost indication is based on China market)
Source- Novozymes,China.
cost, $
Conventional
process
230
min
50
tons 9 m3 92
KWH
Cost, $ 18.8 135 9.2 163
Enzymatic
100
20
44
Process
min
tons 3 m3 KWH 0.7 kg 5 kg
Cost, $ 7.5 45 4.4 7 3.8 67.7
Savings, $ 95.3

13.6 Enzymes effect on color
Hydrolases and oxireductases constituted important class of enzymes which dealt with colour in
textile application. Speaking about how the enzymes affected these applications one said that
when looked at fading, especially of denim, one came across the three classes of cellulase viz.
acid, neutral and engineering. The affect of cellulase on denim and the wash down effect was
attributed to the yarn, which was ring dyed i.e. yarn dyed with indigo was present only on the
outer ring of the denim. Due to affect of enzyme and physical aberration of cellulose, the
exposed areas became white as well as indigo dyed. If it was non denim, it was ring dyed non
denim containing vat, sulphur or pigments. This kind of effect on denim was called salt and
pepper effect. The more contrast, better was the denim wash. Some of the denims had blue or
greyer cast because they were woven with one up or two down and one of the yarn was coloured
while the other wasn’t. thus, the effect was created with the combination of the hydrolysis of 1-4
glucose linkage in cellulose and the abrasion e.g. turbulence of friction of metal to metal or fiber
to fiber led to denim appearance.
Combination of enzyme, sand blasting and bleach evolved a fashion recently. Sand blasting was
enzyme treatments which subject the denim fabric to sand at high pressure with consequent
exposure of white area while blowing off surface colour followed by a treatment of the fabric
again with enzyme, leading to a salt and pepper effect and bleached to reduce the colour value.
Furthermore, after sand blasting, treatment with enzyme followed by over dyeing of the abraded
areas produced typical effects on denim.
13.7 Bio-carbonising
Polyester / cellulosic blends after dyeing and/ or printing are occasionally treated with strong
solution of sulphuric acid to dissolve cellulosic component. The resultant goods are soft and have
a peculiar fluffy feel. This process is risky due to highly corrosive acid that is also difficult to
treat in an ET plant.
The process developed at UNO, has none of the above drawbacks. It offers a safe and eco-friendly
to the obnoxious practice of using sulphuric acid. The goods are treated with cellulose
enzyme based formulation to achieve dissolution of cellulosic fibers.
13.8 Bio-polishing
Bio-finishing also called bio-polishing, is a finishing process applied to cellulose textiles that
produces permanent effects by the use of enzymes. Bio-finishing removes protruding fibres and
slubs from fabrics, significantly reduces pilling, softens fabric hand and provides a smooth fabric
appearance, especially for knitwear and as a pretreatment for printing. Second rate articles can
obtain the high value eye appeal of first rate ones. In denim processing, bio-finishing can reduce
or eliminate abrasive stones and the aggressive chlorine chemistry, achieving the desired “worn”
looks. Bio-finishing is not only useful for cotton but also for regenerated cellulose fabrics,
especially for lyocell and microfiber articles. By incorporating enzymes into detergents to
21

remove protruding surface fibres, improved colour retention is achieved after multiple
launderings. The disadvantages of bio-polishing are the formation of fibre dust, which has to be
removed thoroughly, the reproducibility of the effect (which is dependent upon many
parameters) and in the worst case, loss of tear strength.
Enzymes are high molecular weight proteins produced by living organisms to catalyse the
chemical reactions essential for the organism’s survival. They have complex three-dimensional
structures composed of long chains of amino acids with molecular weights ranging from 10,000
to about 150,000 and occasionally to more than 10, 00,000. These naturally occurring molecules
provide a high degree of catalytic specificity unmatched by man-made catalysts. The enzyme
and substrate form a ‘lock and key’ complex that requires the enzyme to have a specific
molecular alignment in order to act as a catalyst. The lock and key theory of Emil Fischer was
broadened by Koshland Jr to the induced-fit theory of the enzyme-substrate-complex. Chemical
reactions catalysed by enzymes can typically be carried out, as is most usual in nature, under
mild aqueous conditions without the need for high temperatures, extreme pH values or chemical
solvents.
Knitted goods treated with enzymes are free from surface hairiness and neps with much
improved handle and flexibility. The fabric surface becomes smoother and more lustrous. There
is also a lower tendency to further pilling possibly due to the fact that there are less protruding
fibre ends from the yarns after the enzyme application.
13.8.1 Bio-polishing of Knit fabric
Stage-1: One bath Scouring and Peroxide bleaching
Recipe:
Anti-foaming 0.07gm/l
Rucozen WBX (Detergent) 0.5gm/l
Stabilizer SOF 0.5gm/l
Primasol jet (Anti-creasing) 1.5gm/l
Securon 540 (Sequestering) 1gm/l
Caustic 2gm/l
H2O2 2.5gm/l
pH 10-11
Temperature 1050C
Time 50min
22
Stage-2: Bio-polishing
Recipe:
BP Nano 0.9gm/l
Acetic acid 1gm/l
T-100 (Peroxide killer) 0.08gm/l
Securon 540 0.25gm/l
pH 4.5-5
Temperature 550C-600C
Time 40-60min

Process Flow Chart
Fresh water and
fabric Load at 450C
Temperature raise to
600C
Detergent & Peroxide
Stabilizer (Inject)
Run for 5 min
Inject Caustic and run
5min
Raise temperature to
700C
H2O2 inject and run 5
min
1050C
Run for 30 min
Lower the
temperature to 800C
Bath drain
BP Nano & Acetic
acid
Securon 540 &
Peroxide killer inject
550C
Run for 60 min
Rinsing and unload
the fabric.
23

24
Well scoured and
bleached sample
Dye addition
Salt addition ( 2
instalment )
Soda ash addition
( 2 instalment )
Dyeing
Hot wash
Hot wash
Soaping ( at boil )
Hot wash
Cold wash
Bio-polishing
Cold wash
Drying
Well scoured &
bleached sample
Bio-polishing
Cold Wash
Drying
Dye addition
Salt addition
Addition of Soda
ash
Hot wash
Hot wash
Soaping
Hot wash
Cold wash
Drying
Process sequence
Dyeing followed by bio-polishing Bio-polishing before dyeing

25
13.8.2 Process Variables
 Concentration
 Temperature
 pH
 Time
 M : L Ratio
 Mechanical Agitation
To achieve optimum bio-polishing, the process variables have been varied as mentioned below.
 Concentration of enzyme: 0.5%, 1%, 2%, 2.5%, 3% & 4%.
 Temperature: 400C, 45 0C, 500C, 550C & 600C.
 pH: 3-4, 4-5 & 5-6.
 M: L: 1:5, 1:10, 1:15 & 1:20.
 Mechanical Agitation: Vigorous Stirring, Medium Stirring & Without Stirring.
13.8.3 Results
13.8.3.1 Factors affecting bio-polishing
Bio-polishing is affected by many factors. Major ones are Enzyme, Type of Fabric and Process
Variables.
The predominant process variables which control the bio-polishing are Temperature, pH,
Duration of treatment, Material to liquor ratio, Enzyme concentration and Mechanical agitation.
To find the effect of above mentioned factors we have carried out the bio-polishing by following
ways.
1) Keeping M: L ratio, pH and temperature constant and varying the concentration of enzyme.
2) Keeping temperature and pH constant and varying the material to liquor ratio.
3) Keeping M : L ratio constant and varying the temperature.
4) Keeping temp. and M : L Ratio constant and varying the pH of solution.
5) Keeping all these parameters constant and varying the duration of treatment
13.8.3.1.1 Effect of Concentration
Concentration of enzyme is a major factor which affects the performance of the bio-polishing of
the knitted fabric.
There are different types of enzymes available in the market. Each enzyme has an optimum
concentration, pH and temperature range.

In our study, we have used Cellusoft-SO, which is an acid stable cellulase. By varying the
concentration of cellulase and keeping the other parameters, such as pH, temperature, time and
material to liquor ratio constant, we have observed that the best bio-polishing can be obtained at
the following conditions :
M: L 1:8
pH 4.5-5
Temperature 55-600C
Time 40-60min
To observe the effects of conc. of Enzyme on bio-polishing, we have treated knitted fabric with
various concentrations of Cellusoft-SO. 0.5%, 1%, 1.5%, 2%, 2.5%, 3% and 3.5%. Results
obtained are depicted in Table 1.
Effects of concentration of enzyme on bio-polishing
Source- Textile & Engineering Institute, Ichalkaranji.
From this table, it can be concluded that as the concentration of cellulase increases from 0.5% to
2.0%, weight loss increases significantly. Optimum percentage weight loss is obtained at 3%
conc. Increase in conc. of enzyme causes an increase in strength loss. Fabric thickness is
reduced with increase in conc. of enzyme.
Hence 3% conc. of enzyme is the optimum dose.
13.8.3.1.2 Effects of Temperature
Temperature affects the performance of cellulase. Each enzyme has an optimum temperature
range where enzyme activity is maximum. Hence it is essential to determine the optimal
temperature. Increase in temperature decreases the enzyme activity rapidly and the enzyme
action comes to almost zero and the enzymes are permanently deactivated at 700C. Low
temperature shows reduction in reaction speed but does not deactivate the enzyme. It is therefore
possible to use a lower temperature by a longer cycle. The activity of Cellusoft-SO at 400C is
only 50%. It is also observed that every 100C rise in temperature doubles the activity of enzyme,
as long as it is not deactivated.
26
Properties
Result
Concentration of Enzyme
0.5% 1% 1.5% 2% 2.5% 3% 3.5%
Weight loss (%) 0.36 0.77 0.88 1.46 2.09 2.12 2.07
Abrasion (mm) 0.04 0.06 0.07 0.08 0.08 0.09 0.09
Wash fastness 4-5 4-5 4-5 4-5 4-5 4-5 4-5
Pilling rating 3 3 4 4 4 4 4

To observe the effects of temp. on bio-polishing, we have treated knitted fabric with the
following recipe. Results obtained are depicted in Table 2.
M: L 1:8
pH 4.5-5
Concentration 3%
Time 40-60min
Properties
Effects of Temperature of enzyme on bio-polishing
The optimum result is obtained at 550C temperature.
13.8.3.1.3 Effects of pH
pH is also a critical factor affecting the efficiency of bio-polishing. A particular type of cellulase
is most effective and can be operated at a certain specific pH range.
To observe the effects of pH on bio-polishing, we have treated knitted fabric with 3% Cellusoft-
SO at various pH viz. 3-4, 4-5, 5-6, 6-7 & 7-8. Results obtained are depicted in Table 3.
Effects of pH of enzyme on bio-polishing
We have observed that the activity of enzyme is maximum at pH 5 – 5.5. But optimum bio-polishing
27
effect is obtained at pH 4-5.
Result
Temperature
400C 450C 500C 550C
Weight loss (%) 0.75 1.03 1.45 2.56
Abrasion (mm) 0.04 0.06 0.07 0.08
Wash fastness 4-5 4-5 4-5 4-5
Pilling rating 3 4 4 4
Properties
Result
pH
3-4 4-5 5-6 6-7 7-8
Weight loss (%) 0.47 1.21 1.1 0.93 0.86
Abrasion (mm) 0.03 0.08 0.06 0.05 0.04
Wash fastness 3 3 4 3 3
Pilling rating 3 4 4 4 4

13.8.3.1.4 Effects of M: L Ratio
M: L Ratio has a substantial effect on bio-polishing. As the liquor ratio increases the bath conc.
of cellulase decreases, and the fabric weight loss decreases. The dilution affects substantially
enzymatic activity.
To observe the effects of M: L ratio on bio-polishing, we have treated knitted fabric with 3% BP
Nano at various M: L ratios viz. 1:5, 1:10, 1:15 & 1:20.
Recipe:
Concentration 3%
pH 4-5
Temperature 550C
Time 50min
Results obtained are depicted in Table 4. From this table, it is found that as the liquor ratio
increases the pilling rating of treatment sample decreases. At the low M: L Ratio, the fabric
show very low pilling and at higher M: L Ratio, pilling tendency of fabric is more. Thus, pilling
rating goes on increasing with increases in liquor ratio.
Properties
Effects of M: L Ratio of enzyme on bio-polishing
The best result is obtained at 1: 10 M : L Ratio.
13.8.3.1.5 Effects of duration
To observe the effects of duration of enzyme treatment on bio-polishing, we have treated knitted
fabric with 3% Cellusoft-SO for various durations viz. 30 min., 40 min., 50 min. & 60 min.
28
Concentration 3%
pH 4-5
Temperature 550C
M:L 1:10
Result
M: L Ratio
1:5 1:10 1:15 1:20
Weight loss (%) 1.06 1.12 0.62 0.51
Abrasion (mm) 0.03 0.04 0.06 0.06
Wash fastness 4-5 4-5 4 4

29
Results obtained are depicted in Table 5.
Effects of duration of enzyme on bio-polishing
Properties
The best result is obtained at 50 min treatment time.
13.8.3.1.6 Effects of Enzyme treatment on Dyeing property
To observe the effects of enzyme treatment on dyeing property, bio-polishing of cotton knitted
fabric has been carried out before dyeing as well as after dyeing.
Concentration 3%
pH 4-5
Temperature 550C
M:L 1:10
Time 50min
The results obtained are tabulated in Table 6.
Effects of Enzyme treatment on dyeing property (3% shade)
Source- Textile & Engineering Institute, Ichalkaranji
Result
Time(min)
30 40 50 60
Weight loss (%) 0.72 1.01 1.42 2.48
Abrasion (mm) 0.04 0.06 0.07 0.07
Wash fastness 4-5 4-5 4-5 4-5
Properties
Results
Enzymes treatment after dyeing Enzyme treatment before dyeing
Concentration of Enzyme
1% 2% 3% 1% 2% 3%
Weight loss (%) 0.77 1.23 1.89 0.79 1.25 1.93
Abrasion (mm) 0.04 0.07 0.08 0.05 0.06 0.09
Wash fastness 4 4-5 4-5 2-3 3 3-4
Pilling rating 3 4 4 3 4 4
K/S Values 9.6 8.9 8.1 9.9 9.9 9.9

From the above table, it is seen that the properties of pre-dyed enzyme treated sample have been
compared with the properties of pre-enzyme treated dyed sample.
Dyeing with reactive dyes after enzyme treatment results in somewhat deeper shade. It is due to
the surface modification of the knitted fabric before dyeing. This fabric shows poor wash
fastness and rubbing fastness than the pre-dyed enzyme treated sample. The pre-enzyme
treatment does not make any difference in softness and surface modification as compare to pre-dyed
30
enzyme treated sample
The best result is obtained at 50 min treatment time.
13.8.3.1.7 One bath Bio-polishing and dyeing
Enzymatic cellulose degradation is also possible during reactive dyeing. Here the dyeing process
as well as bio-polishing will be affected. Number of washes, time, cost and energy can be saved
by this one bath method. However, it should be noted that there is some reduction in color yield
of reactive dyeing. This is because reactive dyeing is carried out in acidic pH during bio-polishing.
But precaution is taken during addition of soda-ash as reactive dyes require alkaline
condition for its fixation. The fabric is made neutral before adding soda-ash. It is found that
neutral stable enzymes are more suitable in this type of one bath treatment.
Recipe:
Conventional Method One Bath Method
Conc. of Enzyme: 3% Conc. of Enzyme: 3%
M: L Ratio: 1:10 M: L Ratio: 1:10
Temp. : 55 Temp. : 55
Time: 50 mins. Time: 2.5 – 3 hrs.
pH: 4-5
13.8.4 Discussion
 The best result is obtained at 3% concentration of enzyme.
 1:10 M: L ratio gives the best result.
 At pH range of 4-5, enzyme shows maximum activity.
 At 550C temperature, enzyme activity is maximum.
 Mechanical agitation supports enzyme activity.
 Depth of shade increases when enzyme treatment is given before dyeing and the depth
decreases when enzyme treatment is given after dyeing.
 Pilling tendency decreases with application of enzyme.
 One bath application saves energy, time & cost. But the bio-polishing effect is not as
good as the two bath method.
 Wash fastness of the enzyme treated sample before dyeing is very poor.
 Wash fastness of the enzyme treated sample after dyeing is good.
 Wash fastness of one bath enzyme treated sample is moderate.

13.8.5 Advantages of using enzymes for bio-polishing
 Hairiness fluffs and pills are removed.
 Material sticking (the burr effect) is prevented.
 Improved handle
 Achievement of surface smoothness and a clear structural appearance.
 Improved luster.
 Material texture relaxation
 Increased flexibility and therefore a soft handle even with over end products and
31
mercerized fabric.
 Improved sew ability.
 Fast to washing, low pilling tendency, no napping in use, or during care operation.
 Stone wash effect without pumice stone and dyestuff destroying chemicals.
 Poor quality, uneven, napped, knoppy material surface (i.e.) typical second quality goods
are converted into elegant, lustrous, soft, top quality with a fine, high quality surface
appearance.
13.8.6 Disadvantages of this finishing technique
 Loss in weight
 Loss in strength
Cellulases have been used on a large scale for years in medicine analysis, food chemistry and
other industries.
13.8.7 Troubleshooting for bio-finishing
As mechanical agitations important to effect the bio-finishing, only selected processes and
machines can be used, for example tubular fabric preferably cut to open width and treated in
open width washers. In the rope form the loosened fibre particles are filtered out by the fabric
and cannot easily be removed. The pad-batch process, jig or package dyeing machines are not
effective in bio-finishing.
Not all cellulase enzymes give identical results, even with similar fabrics in similar equipment.
Cellulases derived from Trichoderma typically are the most aggressive in their action, whereas
mono-component endo-glucanases often require the most mechanical action to achieve the
desired effects. Slow deactivation of the cellulases during transport and storage can adversely
affect the reproducibility of the resulting effects. If cotton is not washed carefully before bio-finishing,
secondary fibre compounds as residual biocides can deactivate the cellulases. The
same is true for natural or synthetic tannic acids, and resist or fastness improving agents for wool
or nylon in cellulose fibre blends.
Deactivation of cellulases after the desired effects have been achieved is very important. If the
enzyme is not completely removed from the fabric, or is not effectively deactivated, the

hydrolysis reaction will continue, although at a slower rate. As very large molecules, cellulases
cannot diffuse into the crystalline parts of the cellulose fibres. They react on the fibre surface, so
fibre damage takes time. But eventually enough hydrolysis will have taken place to weaken the
affected fabrics or garments, leading to customer complaints and returns.
Undesirable deactivation may be caused by high temperature and time, for example, caused by
transport and storage and also by enzyme poisons such as certain surfactants (especially cationic
ones), formaldehyde-containing products or heavy metal ions. An activation effect on cellulases
was reported by Nicolai and co-workers. Alkaline pretreatment, low concentrations of selected
non-ionic surfactants, polycarboxylic acids and polyvinyl pyrrolidone can enhance the bio-finishing
of celluloses. The use of pH buffers during the hydrolysis reaction is strongly
recommended, especially when abrading denim fabrics. Cellulase enzymes have very narrow pH
ranges of effectiveness and denim fabrics can have significant quantities of residual alkali from
the indigo dyeing process. Buffers are required to maintain the appropriate reaction conditions
for maximum enzyme effectiveness.
Because the effect of processing auxiliaries on cellulase catalysis is difficult to predict, it is
important to evaluate any changes in processing formulas carefully by conducting small scale
trials before making significant changes in production procedures.
Removal of protruding fibers from garment surface using cellulase enzymes is called bio-polishing.
These enzymes are proteins and capable of hydrolyzing cellulose (cotton). In bio-polishing
they act upon the short fibers protruding from fabric surface and make the fibers weak
which are easily removed during washing. This process imparts soft and smooth feel and
reduces fuzz or pilling tendency. This process is applicable to garments made of cotton and its
blends.
Two kinds of cellulases are commercially available, acid cellulases which have activity in acidic
medium in pH range of 4.5 – 5.5 and neutral cellulases which have activity in pH range of 5.5-
8.0. Both these types are active in the range of 450C to 600C.
13.9 Enzyme Wash (Denim)
Industrial washing is one of the most important applied finishing methods on fabric or apparel.
Different washing methods can be applied in case of denim fabrics finishing. To achieve special
outlook as well as to change the fashion, responsible washing methods are stone wash, sand
wash and bleach wash. Denim produced from the fabric with twill weave including warp yarns
dyed with indigo color and undyed or white weft yarns
In recent years, there is an interest in using fully biodegradable enzymes which are
environmentally friendly and nontoxic in the modern textile finishing process. A number of
mechanical and chemical operations can be replaced by enzymatic treatment, which has been
applied to improve fabric quality and comfort.
In the textile industry enzymes are applied mainly to get a cleaner fabric surface with less fuzz,
to reduce tendency to pill formation, to smooth the surface combining with traditional softeners.
32

To improve fabric handle and other valuable properties, softeners are widely used in finishing
operations.
For buying a textile, nice and appealing handle is very often considered most important criterion.
Fabric handle can be influenced by using softener which is analyzed in the research work.
Recently some papers have been published to analyze the change of textile's color after applying
in different finishing methods as clients when choosing an item from shop always pay attention
to its color.
Fabric specification (ends/inch, picks/inch, surface density, warp & weft linear density), fabric
tensile strength, fabric stiffness, seam strength, etc must be treated as important characteristics as
those determine wear durability and longevity. However, the effects of enzyme wash on the
changes of above mentioned characteristics are clearly evaluated in this paper. The aim of this
paper is to determine the effects of enzyme wash on denim apparel characteristics.
33
13.9.1 Materials and methods
The investigation has been carried out with currently popular and fashionable regular denim
garments. Basic characteristics of selected unwashed denim garments are mentioned below-
13.9.1.1 Materials selection
Denim fabric composition: 100% cotton Indigo dye.
Weave: twill 3/1 weave
Ends/inch: 50-51
Picks/inch: 41-42
Surface density (gm/m2): 352-353
Warp linear density (Ne): 6-7
Weft linear density (Ne): 11-12
The denim garments have been processed by various types of enzyme washing and finally
softening method as mentioned below.

13.9.1.1.1 Method of desizing
Denim trousers has been subjected to Enzymatic desizing process for removal of size materials
which were added in the sizing process to reduce ends breakage rate during weaving the fabric.
Here desizing was carried out by using following suitable recipe while maintaining proper time
and temperature.
Table1: Recipe of desizing
Process parameter Amount
Soda ash 400gm
Caustic soda 400gm
Temperature 700C
Time 15min
After desizing the apparel was washed off for two times
13.9.1.1.2 Method of enzymatic wash
By desizing size materials were completely removed from the denim trousers, and after that it
was washed by cellulase enzyme with typical industrial recipe as mentioned below:
Table 2:Recipe of enzyme wash
SL enzyme 400gm
Acetic acid 200gm
Anti back staining agent 200gm
Temperature 400C
Time 12min
During enzymatic treatment removed indigo dye can be re- deposited on the white or undyed
weft yarn of denim fabric which is known as back staining process and it can diminish the
outlooks of the trousers. So anti back staining agent was used here to resist back staining. After
washing with enzyme, the trousers were washed off for two times.
13.9.1.1.3 Method of softening
After sand blasting and enzyme wash, silicon softener was used to make the denim fabric soft
and improve handle property, as explained below in table 3.
Table3: Recipe of fabric softening
Softener(Cationic) 200gm
Wash 2 times
Temperature Room temp.
Time 5min
After softening the apparel was washed off for two times.
34

13.9.1.1.4 Method of changes evaluation
Change of Fabric handle property:
Fabric handle property was checked properly before and after enzyme washing by feeling or
touch.
Change of Fabric Specification:
By counting glass ends/inch and picks/inch were calculated from denim fabric of the trousers.
GSM cutter was used to calculate the surface density (gram/square meter) of denim fabric by
ISO 7211. To determine the warp and weft linear density (count) from denim trousers, Beesleys
direct reading balance was used by following ISO
7211/4:1984.
Change of fabric Strength:
Tensile strength of denim fabric was calculated by the help of fabric strength tester. EN ISO
13935 – 2; 1999Grab method was used for Tensile Strength measurement.
Change of fabric Stiffness:
Stiffness of denim fabric was measured by fabric stiffness tester.
Change of Seam Strength:
Seam strength of trouser was measured by seam strength tester. Methods: ISO 13935-2: 19999E
ASTM D 1683: 2007
Figure 7- Raw Sample Figure 6-After wash Sample
35
13.9.2 Results and discussions
13.9.2.1 Changes of Fabric Handle after washing
Enzyme washes Portions of denim garments:
Before wash: Harsh feeling and rough surface.
After wash: More soft and smooth surface.

13.9.2.2 Changes of fabric specification after washing
Table 4: Effects of enzymatic wash on fabric specifications
36
Item No. of
Observation Before wash After wash Difference % of
Difference
Average % of
Change
EPI
1 41 44 +3 +7.32
+6.88
2 40 43 +3 +7.50
3 39 42 +3 +7.69
4 42 44 +2 +4.76
5 42 45 +3 +7.14
PPI
1 38 42 +4 +10.53
+7.33
2 39 41 +2 +5.13
3 40 42 +2 +5
4 38 41 +3 +7.89
5 37 40 +3 +8.11
Warp count
(Ne)
1 7 10 +3 +42.86
+34.52
2 8 10 +2 +25
3 7 9 +2 +28.57
4 7 10 +3 +42.86
5 6 8 +2 +33.34
Weft count
(Ne)
1 9 10 +1 +11.12
+13.39
2 8 9 +1 +12.50
3 9 11 +2 +22.23
4 10 11 +1 +10
5 9 10 +1 +11.12
Surface
density
(gm/m2)
1 337 335 -2 -0.59
-0.825
2 336 333 -3 -0.89
3 338 335 -3 -0.88
4 337 334 -3 -0.89
5 339 336 -3 -0.88
As seen from the table above, for five (5) observations, it is clear that during enzyme wash the
value of fabric surface density finally decreased though ends/inch (EPI) and picks/inch (PPI)
increased.

13.9.2.3 Changes of Fabric strength after washing
Table 5: Effects of enzymatic wash on fabric strength
37
No. of
Observation
Before
wash(gm)
After
wash(gm) Difference(gm) % of
Difference
Average % of
Change
1 460 300 -160 -34.78
-33.68
2 455 305 -150 -32.96
3 465 315 -150 -32.25
4 470 310 -160 -34.04
5 465 305 -160 -34.40
From the table as above, for five (5) observations, it is clear that after enzyme wash the Seam
strength of denim fabric strength has been decreased from the values obtained before washing.
13.9.2.4 Changes of Seam strength after washing
Table 6: Effects of enzymatic wash on seam strength
No. of
Observation
Before
wash(gm)
After
wash(gm) Difference(gm) % of
Difference
Average % of
Change
1 85 67 -18 -21.17
-22.334
2 83 65 -18 -21.68
3 87 66 -21 -24.13
4 86 67 -19 -22.09
5 84 65 -19 -22.61
From the table as above, for five (5) observations, it is clear that after enzyme wash the Seam
strength of denim fabric strength has been decreased from the values obtained before washing.
13.9.2.5

13.9.2.6 Changes of Stiffness after washing
Table 7: Effects of enzymatic wash on fabric Stiffness
38
Direction
Side
No. of
Observation
Before
wash(gm)
After
wash(gm)
Difference(
gm)
% of
Difference
Warp
Face
1 4.45 2.8 -1.65 -37.08
2 4.55 2.9 -1.65 -36.25
Back
1 3.75 2.6 -1.15 -30.67
2 3.80 2.5 -1.30 -34.21
Weft
Face
1 2.40 2.3 -0.1 -4.17
2 2.35 2.2 -0.15 -6.38
Back
1 2.30 2.5 -0.2 -8.69
2 2.30 2.4 -0.1 -4.35
From the table for two (2) observations along the warp and weft directions for both face and
back side of denim fabric, it is clear that after enzymatic desizing process, size materials were
removed from the fabric and for softening, the stiffness of denim fabric has been decreased
which indicating the increase of fabric softness.
13.9.3 Discussion
Denim trousers were chosen as apparel and after washing, changes on characteristics of denim
trousers has been observed.
It is concluded that after enzyme wash the denim fabric changed from harsh to softer. Due to
abrasion damage ends/inch and picks/inch of denim fabric has been decreased and as a result
surface density of fabric increased. Again tensile strength of fabric and seam strength of trousers
has been decreased due to enzyme washing.
Stiffness of denim fabric has been decreased after washing which results in the increase of denim
fabric softness. To hold the qualities of sewn apparel it is very necessary to observe the effects of
enzyme wash on denim apparels.

13.10 Textile Auxiliaries
Textile auxiliaries such as dyes could be produced by fermentation or from plants in the future
(before invention of synthetic dyes in the nineteenth century many of the colors used to dye
textiles came from plants e.g. woad, indigi and madder). Many microorganisms 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. It is not unusual for some species
to produce up to 30% of their dry weight as pigment. Several fo 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 of dye intermediates by controlled fermentation techniques replacing chemical
syntheses, which have inherent waste disposal problems (e.g. toxic heavy metal compounds).
The production and evaluation of microbial pigments as textile colorants is currently being
investigated.
Another biotechnological route for producing pigments for use in the food, cosmetics of 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 new range of cosmetics. Traditionally, shikonin was extracted from
the roots of five year old plants of the species Lithosperum erythrorhiz where it makes up about
1 to 2 per cent of the dry weight of the root,. Din tissue culture, pigment, yields of about 15 per
cent of the dry weight of the roof cells has been achieved.
13.11 Enzymatic Decolorization
In textile dyeing as well as other industrial applications, large amounts of dyestuffs are used. As
a characteristic of the textile processing industry, a wide range of structurally diverse dyes can be
used in a single factory, and therefore effluents from the industry are extremely variable in
composition. This underlines the need for a largely unspecific process for treating textile waste
water. It is known that 90% of reactive dyes entering activated sludge sewage treatment plants
will through unchanged and be discharged in to rivers.
High COD and BOD, suspended solids and intense colour due to the extensive use of dyes
characterize wastewater from textile industry, especially process houses. This type of water must
be treated before discharging it into the environment. The water must be decolorized; harmful
chemicals must be converted into harmless chemicals.
Biological treatments have been used to reduce the COD of textile effluents. Physical and
chemical treatments are effective for color removal but use more energy and chemicals than
biological processes. They also concentrate the pollution into solid or liquid side streams that
require additional treatments or disposal, on the contrary biological processes completely
mineralize pollutants and are cheaper. Instead of using the chemical treatments, various
biological methods can be used to treat the water from the textile industry. These methods
include, Biosorption, use of Enzymes, Aerobic and anaerobic treatments etc. Only
biotechnological solutions can offer complete destruction of the dyestuff, with a co-reduction in
39

BOD and COD. In addition, the biotechnological approach makes efficient use of the limited
development space available in many traditional dye house sites.
14 Enzyme Inactivation
To prevent any damage of the fabric after the finishing operation it is very essential that the
reaction be terminated at the end of treatment by enzyme inactivation. If the enzyme is not
inactivated entirely then at the end of the reaction fibres get damaged and even extreme cases
total destruction of the material may result. The enzyme inactivation is therefore of great
importance from the technical point of view.
There are two distinct process of termination of enzyme:
1) Hot treatment at 800C for 20 min.
2) By raising the pH to 11–12.
15 Why the industry owner should use Bio-technology in textile
40
processing
 The importance of using bio-technology in Textile is worth-mentioning. Let us know
some of them-
 Enzymatic process enhances the variety of plants used in Textile Fibre productions. It
also influences the inner properties of fibres.
 It is very useful during waste managing.
 Prevents the adulteration.
 Bio-technology helps the quality control.
 Enhance the low energy type detergents.
 Using enzymes in finishing department.
 Used instead of harmful dyestuffs and chemical treatments.
 Tend to use micro-organism and bio-polymer in Textile which develops the total process
of textile.
 Bio-Stonewashing has opened up new possibilities in denim finishing by increasing the
variety of finishes available. For example, it is now possible to fade denim to a greater
degree without running the risk of damaging the garment. Productivity can also be
increased because laundry machines contain fewer stones or no stones and more
garments.
Hopefully, the uses of Bio-Textile are increasing day by day.

16 Conclusion
It can be seen from what has been discussed that the field of the
biotechnology remains one of the most promising for textile industry to seek out
high quality, high added value finishes. Collaboration with biotechnology field
to make the research product for the textile industry into the commercial
reality in the textile finishing plant will be needed to decrease the lead time
environment problem and minimize the profitability innovation and novelty in
the enzyme will be necessary to stimulate the more discerning the consumer
market and to develop specialty and niche market for textile fabric industry.
Bio-processing with its pervasive field of application surely going to conquer
the world of textiles and will make it to rich the pinnacle of its performance.
There are few to enunciate, however many such potentials are yet to explore.
Bio-processing in textiles provides to be a boon to the ever changing
conditions of the ecology as well as economy.
41

42
Reference
1. “Bio- Processing Of Textiles” by Abhishek Jadhav & Javed Sheikh.
2. “Chemistry & Technology of Fabric Preparation & Finishing” by Dr. Charles Tomasino.
3. “Applying Enzyme Technology for Sustainable Growth” by Guifang Wu, Han Kuilderd &
Sonja Salmon (Novozymes).
4. “Bio Polishing of Knit Goods” by Prof. S.K. Laga, Prof. Dr. A.I. Wasif & Mr. Karan Shah
(Textile & Engineering Institute, Ichalkaranji).
5. “CIRCOT’s Eco-friendly Process for Scouring of Cotton Textile: Bio-scouring” –Annual
article of Central Institute for Research on Cotton Technology, Mumbai.
6. “Bio-vision in Textile Wet Processing Industry- Technological Challenges” by C.
Vigneswaran, N. Anbumani and M. Ananthasubramanian. Journal of Textile &
Apperal, Technology & Management; Volume 7, Issue 1, spring 2011.
7. “Effects of industrial enzyme wash on denim apparel characteristics” by M. M.
Rahman, Daffodil International University. www.ptj.com.pk ; January 2011.

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