effect of proteolytic enzymes on dye yield of silk

EFFECT OF PROTEOLYTIC ENZYMES ON DYE YIELD OF SILK

PROJECT SUPERVISOR- UNDERTAKEN BY- Dr. J.N. CHAKRABORTY AJEET KUMAR – 10110001

KETAN KUNDAL- 09110004 REWA- 10110040

SHUJA HUSSAIN- 10110052

Area of work

Silk is conventionally dyed with metal complex dyes for brighter

shade and excellent colour fastness. However dye strength of

dyeings (K/S) remain out of satisfaction because of bigger size of

dye molecules. In this work attempts were made to promote dye

strength of silk by using proteolytic enzymes.

Problems of conventional dyeing

• During conventional dyeing maximum dye uptake is only up to 60% – 70%.

• Used dye is drained out, which causes various difficulties during waste treatment.

• Problem of emission of effluents in environment.

Objective

• To increase the dye yield of silk by using proteolytic enzymes.

Literature survey

• Silk is a natural fibre that is mainly composed of proteins and amino acids.

• Silk exhibits wide acceptability for all types of dyestuffs and hence a broad spectrum of colours are available for dyeing of silk fabrics.

• Silk has good affinity towards dye molecules due to its ability to form large no of hydrogen and electrostatic bonds.

• Premetallised dyes show great affinity towards protein fibres like silk.

• Enzymes are biological catalyst that catalyze a reaction and are highly selective in nature.

• For silk the enzymes that are used are proteolytic enzymes like pepsin , trypsin, papain (natural enzymes) and protease (synthetically manufactured).

Plan of work

• Dyeing of silk conventionally• Dyeing of silk with different proteolytic enzymes

PapainTrypsinPepsinProtease

• Studying the effects of different enzymes for different parameters

• Comparison of conventional dyeing and enzymatic dyeing

Experimental plan

• Fabric used-silk (degummed)• Dyes- 1:2 Metal complex dye• Chemicals used

Acetic acid, Non ionic detergent, Sodium carbonate• Enzymes used – Proteolytic enzymes

Natural - Papain, Trypsin, Pepsin, Synthetic - Protease

• Instrument used Water bath , Open bath dyeing machine, Computer

Colour Matching, Universal Testing Machine, Shirley stiffness tester

Methodology

• Conventional dyeing - Optimization of Temperature - 40 ˚C to 90 ˚C

Time - 1hr, 1.5 hrs, 2 hrs pH – 2 to 6.5

• Enzymatic dyeing - Optimization of Temperature - 30 ˚C to 90 ˚C

Time - 1hr, 1.5 hrs, 2 hrs pH – 2 to 6.5 Concentration – 0.1% to 1.0%

Conventional Dyeing

Heating of water bath up to required

temperature

Introductionof dye

Introduction of pre wet

sample

Dyeing for required time

periodWashing and

SoapingDrying

Enzymatic Dyeing

Heating of water bath up to required

temperature

Pre treatment of fabric with

enzyme for 10 mins

Dyeing of sample for

required timeWashing and

soapingDrying

Introduction of dye

Testing

• Reflectance value• Tensile strength• Stiffness test• Fastness

Wash fastnessRubbing fastnessLight fastness

• Crease recovery test

Results and Discussions

• Conventional dyeing

Surface colour strength (K/S)vs

Temperature of dyeing

0 40 50 60 70 80 900

0.5

1

1.5

2

2.5

3

3.5

4

4.5

red blue

orange scarlet

green

Temperature (° C)

K/S

Surface colour strength (K/S)vs

Time of dyeing

0 1 1.5 20

0.51

1.52

2.53

3.54

4.55

Scarlet OrangeRed GreenBlue

Time (°C)K

/S

Surface colour strength (K/S)vspH

2 2.5 3 3.5 4 4.5 5 5.5 6 6.50

1

2

3

4

5

6

7

8

orange bluegreen redscarlet

pH

K/S

• Enzymatic dyeing

Surface colour strength (K/S) vs

Temperature for natural enzymes for Red

0 40 50 60 70 80 900

0.5

1

1.5

2

2.5

3

3.5

4

4.5

redblueorangescarletgreen

Temperature (° C)

K/S


Temperature for natural enzymes for Blue

0 30 50 700

0.5

1

1.5

2

pepsin trypsin

papain conventional

Temperature (°C)

K/S


Temperature for natural enzymes for Orange

0 30 50 70 900

0.5

1

1.5

2

2.5

pepsin trypsin

papain conventioanl

Temperature (°C)

K/S


Temperature for natural enzymes for Green

0 30 50 700

0.2

0.4

0.6

0.8

1

1.2

1.4

pepsin trypsin

papain conventional

Temperature(°C)

K/S


Temperature for natural enzymes for Scarlet

0 30 50 700

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

pepsin trypsinpapain conventional

Temperature(C˚)

K/S


Concentration for Papain

0

0.5

1

1.5

2

Concentration

K/S

Surface colour strength(k/s) vs

Temperature for protease enzyme

0 30 50 70 900

0.5

1

1.5

2

2.5

3

3.5


Temperature(˚C)

K/S


Time for protease enzyme

0 1 1.5 20

1

2

3

4

5

6

Sacrlet OrangeRed Green

Time(hr)

K/S


pH for protease enzyme

2 2.5 3 3.5 4 4.5 5 5.5 6 6.50

0.5

1

1.5

2

2.5

3

3.5

4


pH

K/S


Concentration for protease enzyme

0 0.1 0.2 0.3 0.4 0.5

0.600000000000001

0.700000000000001 0.8 0.9 10

0.5

1

1.5

2

2.5

3

3.5

4

Scarlet Orange RedGreen Blue

pH

K/S

Comparison of Surface colour strength(k/s)

The dye yield of protease enzyme significantly higher than conventional dyeing.

Scarlet Orange Red Green Blue0

1

2

3

4

5

6

Conventional Protease

Shades

K/S

Tensile strength of dyed fabric for different enzymes

Tensile strength of undyed sample- 201.1 N

Dyeing with enzymes lead to decrease in tensile strength of the fabric. The decrease in strength for the enzymes with respect to conventional dyeing are as follows-

Pepsin-11% Trypsin-3%Papain-2% Protease-4%

Stiffness

Dyeing with enzymes decreases the stiffness of fabric as compared to conventional dyeing. The flexural rigidity of protease dyed sample is lesser than conventionally dyed samples.

Crease recovery

Dyeing with enzymes leads to better crease recovery of fabric.

Fastness

Wash fastness- Conventional dyeing : 3 - 4 Enzymatic dyeing : 4 – 5

Rubbing fastness- Conventional dyeing : wet – 5, dry - 5 Enzymatic dyeing : wet – 5, dry - 5

Light fastness - Conventional dyeing : 5 - 6 Enzymatic dyeing : 5 – 6

Conclusion

• Optimum parameters for conventional dyeing of silk are-Time- 1.5 hours,Temperature-90˚C,pH- 5.5

• Optimum parameters for enzymatic dyeing of silk are- Pepsin, trypsin, and papain-

Time- 1.5 hours,Temperature-70˚ C,pH- 5.5Protease-

Time- 1.5 hours,Temperature-90˚ C,pH- 4.0• The results obtained by use of pepsin, trypsin and papain does

not show very significant improvement over conventional dyeing.

• The results obtained by use of protease shows significant improvement over conventional dyeing.

• Dyeing with enzymes lead to decrease in tensile strength of the fabric. The decrease in strength for the enzymes with respect to conventional dyeing are as follows-

Pepsin-11%,Trypsin-3%,Papain-2%,Protease-4%• Dyeing with protease enzyme leads to increase in washing

fastness.• Dyeing with protease enzyme leads to increase in softness of

fabric and also an increase in crease recovery.

References

• Reddy R M, Innovative and multidirectional applications of natural fibre: silk-a review, Academic journal of entomology, 2009,71-75

• Turbiani F R B, Tomadon J, Seixas F L, Gimenes M L, Properties and structure of sericin films- effect of cross linking degree, Department of chemical engineering, State university of Maringa.

• Gowda K N N, Padaki N V, Sudhakar R, Subramani R, Eco friendly preparatory process for silk: degumming by protease enzyme, Man -made textiles in India, Jan 2007, 28-31

• Krishnaveni V, Study on effect of proteolytic enzyme degumming on dyeing of silk, Colourage, August 2010,61-68

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effect of proteolytic enzymes on dye yield of silk

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