Effect of Acid Cellulase at Different Concentration and Parameters on Wet Processing of Knitted Fabric Part-2

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THE CHEMISTRY OF ENZYMES:
Enzymes are naturally-occuring proteins capable of catalysing specific chemical reactions and being catalysts, facilitate the reaction without being consumed. After catalysing the chemical reaction, therefore the enzyme is released and is able to catalyse another reaction-and so on.Enzymes have a protein like structure with primary, secondary, tertiary and quaternary structures and are susceptible to denaturing (degradation due to temperature, ionising radiation, light, acids, alkalies and biological effect factors). The textile and clothing sector is now a major user of enzymes during manufacturing and after-care. Table-1 summerises some of the already important established enzymes. Cellulases are widely used in textile application. Cellulases are high molecular colloidal protein catalysts in metabolic form and are commonly produced by soil-dwelling fungi and bacteria.
Industrial cellulases are complexes of a number of cellulases, cellobiase and related enzymes in non-uniform composition, with molecular weight ranging from 10,000 to 4,00,000. Cellulases comprise a multicomponent enzyme system, including endoglucalases (EGs) that hydrolyse cellulose chains randomly, cellobiohydrolases (CBHS) that split cellobiose from cellulose ends, and cellobiases that hydrolyse cellobiose to glucose. EG or EG-rich preparations are best for aging and defibrillation of fibre surfaces, while complete cellulase systems are best for cleaning and depilling effects. In general, there are two major commercial classifications ofcellulase enzymes based on optimum ranges _9 'acid cellulases' exhibit the most activity within the pH range 4.5- 5.5, at a temperature of 45-55~ ; while 'neutral cellulases' ', are more effective in the 5.5-8.0 pH range at 50-60~ Currently, acid cellulases and neutral cellulases are more commonly used. With alkaline cellulases, there is a possibility of applying the enzymes in combination with reactive dyes from a dye bath.

MECHANISM OF ENZYME ACTION ON COTTON TEXTILES

Enzyme' s effect mechanism, i.e. enzyme catalysis, operates first of all to form an enzyme substrate complex. Direct physical contact of enzyme and substrate is required to obtain the complex. The current proposed mechanism of cellulase action is illustrated in Fig. 1.
However, the mechanism of enzymatic hydrolysis of cellulosic materials is complicated and not yet fully understood. Enzymes contain true activity centre in the form of three dimensional structures like fissures, holes, pockets, cavities or hollows. Endoglucanases or endocellulases hydrolyse cellulose polymers randomly along the chains, preferably attacking non-crystalline region. Cellobiohydrolases or exo-cellulases, attack the polymer chain ends and produce cellobiose. Coupled with the binding domains associated with the enzyme, exo-cellulases may assist in degradation of cellulose by disrupting the local crystalline cellulose structure, which makes the region more susceptible to subsequent hydrolysis by endo-cellulases. Fig-2 shows the reducing and non-reducing end groups by the action of cellulase on 1,4-[3-glycoside bond lase on 1,4-[3-glycoside bond of the cellulose molecule. [3-glucosidases hydrolysc small chain oligomers, such as cellobiose into glucose. 

The three types ofcellulasc component act synergistically in degrading cellulose to glucose. Synergism of di fferent components in the cellulase complex and inhibition mechanisms further complicate the reaction. Enzyme diffusion plays a much more decisive role inthe heterogeneous system of soluble enzyme and solid substrate. The kinetics of reaction therefore depend on the diffusion of enzyme to and into the solid phase of the substrate and the diffusion of the reaction products out of the solid phase into the liquor. For cotton, the restriction of the enzyme to the fibre surface is easily achieved because cellulose is a highly crystalline material and possesses only small amorphous areas, making the diffusion of enzymes into the interior of the fibre nearly impossible. Thus, by regulating enzyme dosage and choosing the right type of enzyme, the catalytic action of the enzyme can be confined to the surface of cotton and to the amorphous regions, leaving the fibres, as a whole, intact. 
OBJECT:
  1. To know the effect of acid enzyme (low & high conc.) on knitted fabric.
  2. To know the effect on wash fastness properties of fabric due to use acid enzyme.
  3. To know the effect on rubbing fastness properties of fabric due to use acid enzyme.
  4. To know the effect on perspiration fastness properties of fabric due to use acid enzyme.
  5. To know the whiteness (Reflectance) properties of both treated & untreated fabric by using data color.
MATERIAL & METHOD:

1. Material specification:
  • Fabric type : single jersey
  • GSM : 160
  • Sample wt : 10gm
2. About acid cellulase :
  • Brand name : Lerzyme 2000
  • Country : china
Processing method:

1. Enzyme treatment recipe: Acid cellulase (Bio-polish enzyme )
  • Lerzyme 2000 : High conc.- 0.1-0.4%, Low conc.- 0.4-0.8%
  • PH : 5
  • M:L = 1:10
  • Temp : 50-60ºC
  • Time : 1hr
2. Dyeing recipe: Scouring & Bleaching
  • NaOH = 5gm/l
  • H2O2 = 5gm/l
  • Wetting agent = 2gm/l
  • Sequestering agent = 2gm/l
  • Stabilizer = 2gm/l
  • M:L = 1:15
  • Temp. = 105°C
  • Time = 50min
  • Sample = 5gm
  • Dyes = according to shade
DYEING SEQUENCE:

M/C load

Detergent & other chemical

70ºC X 10ʹ

DRAIN

NORMAL WACH
↓5-10ʹ
WATER FULL

SCOURING CHEMICAL(INJECT)

CAUSTIC(DOSING) 50-60ºC

H2O2 @ 70ºC

98ºC 50ʹ

DRAIN

RINSE

ACID

PH CHECK

ENZYME
↓55ºC X 1hr
SAMLPE CHECK

70ºC X 5ʹ

DRAIN

RINSE

LEVELLING & OTHER CHEMICAL

SALT DOSING

COLOR (DOSING)
↓10ʹ
SODA DOSING

STEAM (60ºCX 60ʹ)

COOLING

SAMPLE CHECK

DRAIN

RINSE

NORMAL HOT 70ºCX10ʹ

ACID

DRAIN

ACID SAMPLE CHECK

DRAIN

RINSE

SOFTENER
↓ 10ʹ
FINAL SAMPLE CHECK

UNLOAD


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