Application of Bio technology in Textile Wet Processing

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Application of Bio technology in Textile Wet Processing

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  • 1. 1 Personal Details of Student Daffodil International University Faculty of Engineering Textile Engineering Department Family Name Md. Shahiduzzaman Given Name (s) Shuvo ID 111-23-2350 Email shahid23-2350 @diu.edu.bd Assignment Details Assignment Title Application of Bio-technology In Textile Wet Processing Course Code TE-408 Course Title Specialized Wet Processing Submitted To Asst. Professor Sumon Mazumder Submission Date Declaration: 1. This work is substantially my own. 2. The assessment has not been submitted previously for assessment in this or any other unit, or another institution 3. I have retained a duplicate copy of the assignment. Md. Shahiduzzaman Shuvo
  • 2. 2 1. Application Of Bio-technology In Textile Wet processing Introduction: The textile wet processing sector is the one of the biggest production sector of Asia which drain highest amount of hazardous effluent and directly involved to create ambient problem now it is became serious problem to major textile producing zones like Pakistan ,China, India ,Bangladesh. It also creates negative impact on textile market of those countries who doesnt take serious action against environmental issues like zero drainage eco-friendly products. Therefore, The researchers and scientists are working to solve economical, ecological, eco- friendly issues by troubleshooting converting the chemical treatments into biological treatments, recently successful working on biological treatments appeared in the field of wet processing specially in pretreatment sector and are in industrial practices biological evolution. [1] Application of living organism to the industries are called bio textile. Biotechnology in Textile Processing examines recent trends, techniques, and developments in the finishing and processing of natural fibers. Bio textiles are structures composed of textile fibers designed for use in specific biological environments where their performance depends on biocompatibility and bio stability with cells and biological fluids. Bio-Textile is the latest and updated technology for Textile Industry where the Enzymes are used in different process in order to achieve different goals. Living organism is used to carry out the enzymatic process. Bio textiles include implantable devices such as surgical sutures, hernia repair fabrics, arterial grafts, artificial skin and parts of artificial hearts. [2]
  • 3. 3 1.1 Importance of Bio-Technology in Textile 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 Fiber productions. It also influences the inner properties of fibers. The influence of enzymatic pre-treatment on color of bleached and dyed flax fibers 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 develop the total process of textile. Enzymatic scouring for better textile properties of knitted fabrics Designing wood fiber morphology and mechanical properties of fiberboards Enzymatic finishes of wool fabrics The effects of ultrasound on the performance of industrial enzymes used in cotton bio-preparation and bio-finishing applications [3] 2. What are Enzymes? Enzymes are the organic complex & soluble bio-catalysts, formed by living organisms that catalyze chemical reaction in biological process. Enzymes are quite specific in their action on a particular substance. A small quantity of enzyme is able to decompose a large quantity of substance it acts upon. Enzymes are usually named by the substances degraded in the reaction it catalyzes. They are naturally occurring high molecular weight proteins. Their molecular weight ranges from104 105. [3]
  • 4. 4 2.1 Properties of Enzyme I. Enzymes are living organism which is based on protein. II. Its main function is fermentation of starch. III. Soluble in water & insoluble in acid & alcohol. No risk of hydrocellulose formation during pilling. [4] An enzyme accelerates the rate of particular reaction by lowering the activation energy of reaction. IV. Enzymes operate under mild condition that means each enzyme have its optimum temperature & pressure. So this is easy to control V. Enzymes are biodegradable & environment friendly. 2.2 Factors affecting the efficiency of Enzymes: 1) Substrate concentration 2) pH value 3) Temperature 4) Time 5) Activator 6) Inhibitor [5] 2.3 Types of Enzyme According to the source Enzymes are Mainly 2 types: 1. Vegetable Enzyme 2. Animal Enzyme: Enzymes which we get from slaughterhouse wastes like pancreas, cattle blood lever. Example: Pancreatic (which form milky emulsion in water & capable of modifying starch, albumen, pectins & fats), Novofermasol, Degomma Working condition: Temperature-50C-55C, pH- 5.5-7.5 Vegetable Enzymes are two types:
  • 5. 5 I. Malt extract Enzyme: Malt extract is made from germinated barley or extraction of fresh barley cones. These are particularly used in desizing process. Trade name: Ferment D, Terhyd MD, Diastafor, Diastase, Maltostase. Working condition: Temperature- 55C-60C, pH- 6-7.5 II. Bacterial Enzyme: Enzymes which are commercially produced by growing cultures of certain microorganisms (i.e. fermented rice produce bacteria Extract grow enlarge prepared). Working condition: Temperature-70C-75C, pH- 6.5-7.5 Trade name: Rapidase, Biolase, Bactolase, Gelatase, Acry, Protease, Catalase. [6] 2.4 Role of Enzymes In textile Wet-Processing Enzymes are proteins formed by long linear chains of amino acids linked by peptide bonds. They are present in all living cells which carry out vital functions in the metabolic process, of growth & cellular reproduction, transforming & conserving energy. They are biological catalysts capable of notably accelerating the chemical reactions which occur in living organisms. They are produced by cells, but they arent viruses or bacteria & they cant reproduce autonomously; they are therefore alive even though not biologically active, in determined conditions of pH, temperature, liquor composition & so on. From the beginning of nineties till today, the biggest development of modern enzymology is made in the textile segment with the introduction of [7] (Enzymes used in Textile & their effects): Enzyme Effects 1) Amylose Amylase is used in desizing that hydrolyses & reduce the molecular weight of amylose & amylopectin molecules in starch, rendering it water soluble enough to be washed off the fabric.
  • 6. 6 2) Cellulase Cellulase enzymes are used in cotton bio-polishing which selectively acts on the loose fibers protruding from the fabric or yarn surface. This enzyme can also be used in bio-stoning of jeans. 3) Pectinase Pectinase enzyme is used in bio-scouring of cotton to remove hydrophobic (oils, fats) & other non-cellulosic components (dusts, dirts). Retting of Flax and Hemp. 4) Catalase After bleaching with hydrogen peroxide (22), Catalase enzyme is used in the subsequent process which functions to catalyze the decomposition of hydrogen peroxide to water (2) & oxygen (2) 5) Protease Protease is used in the scouring of animal fibers, degumming of silk & modification of wool fiber properties. [8] 6) Laccase Laccase enzyme is used for oxidation of dyes such as Indigo [9] Peroxidases Used as an enzymatic rinse process after reactive dying, oxidative splitting of hydrolyzed reactive dyes on the fiber and in the liquor, providing better wet fastness, decolorized wastewater and potentially toxic decomposition compound. Ligninases Removal of burns and other plant compound from raw wool. Collagenases Removal of residual skin parts in wool. Esterases 1. In development polyester finish removal of oligomers. 2. In development polyacrylonitrile preparation for better coloration. 3. Polyester finish (removal of oligomers) 4. Reduction of hydrophobicity and electrostatic charges of polyester [10]
  • 7. 7 Amidase Finishing of Nylon Nitrilase Finishing of Polyacrylonitrile Xylanases Carbonizing of wool [11] 2.5 Enzymatic Desizing Enzymatic desizing is the classical desizing process of degrading starch size cotton fabrics using enzymes. Amylase are the enzymes that hydrolyze & reduce the molecular weight of amylose & amylopectin molecules in starch, rendering it water soluble enough to be washed off the fabric. [12] The modern agencies used desizing into three groups. The only amylase convert the starch mixture very rapidly soluble Dextrin & then more slowly convert this to reducing substances & sugar, such as maltose. Starch (Insoluble) Dextrin (Insoluble) Soluble Dextrin Maltose Alpha glucose (soluble) [13] 2.5.1 Action of Amylase Enzyme in Enzymatic Desizing Amylase enzymes are used in enzymatic desizing process that consists of two parts, amylase & amylase. amylase attacks the starch chain randomly so that the degree of polymerization of starch is rapidly reduced & be transferred into Glucose (6126) & Water (2). amylase successively removes the terminal Maltose unit so that the polymeric chain can be shortened gradually. [14]
  • 8. 8 Most of the companies offer 2-3 types of desizing enzymes that can be used for different temperature & pH ranges. At Matex, a universal kind of desizing enzyme, Metazyme BIO-DS has been developed which can be used at varied pH & temperature range. [15] 2.5.2 Advantages of Enzymatic Desizing: No risk of mildew formation on fabric in enzymatic desizing, which observed in rot steeping or acid desizing process. No risk of hydro-cellulose formation in fabric, which are seen in the acid desizing. There is no risk of shrinkage problem which can be observed in case of alkali desizing. Less time consuming process so higher production can be achieved. It is also a economic process Fiber damage is very less. Amylase enzyme used in desizing is bio-degradable 7 environment friendly. So, effluent load from this process is very less. [16] 2.6 Enzymatic Bio-Scouring: A Cost Effective and Eco-friendly Process for the Generation Next The bio-scouring of raw cotton as an alternative to alkaline scouring has been studied in depth over recent years. The basic idea is simply that of hydrolyzing those non-cellulosic components responsible for water repellency of cotton, using enzymes. This is done by using a specific degradation process in delicate pH & temperature conditions & then removing them with a successive hot rinse. The Pectinase destroys the structure of the cuticle, hydrolyzing the pectins & removing the links with wax & protein, as well as between these & the remaining fiber structure. The pectin links the wax to the cellulose of the primary wall, but it is not necessary to eliminate all the pectins for providing hydrophilic properties. Even when 30% of the residual pectins remains on the fabric, a wash at 80C-90C after a dwelling stage eliminates the solubilized waxes.
  • 9. 9 2.6.1 Advantages of Bio-Scouring over Traditional scouring: 1. Saving of water & energy. 2. Lower environmental impact & easier to treat wastewater. 3. Better compatibility with other processes, machinery & materials. 4. Lesser attacks on the fiber structure, loss of weight & resistance. [17] 5. Quality perspective: To get the adequate absorbency for further subsequent processes. To get the minimum degree of whiteness for medium to dark shades and maximum degree of whiteness for light and white shades. The AATCC recommended absorbency standard for drop test is in the range of (1- 5) sec. So the absorbency of bio scoured fabric is quite satisfactory. Treatment Absorbency (time) Scourzyme L ( 0.4%) 3 sec. Scourzyme L ( 0.5%) 2 sec. Scourzyme L ( 0.6%) 1 sec. Caustic scouring 1 sec. 6. Economic perspective: Bio scouring process is very much economical and cost effective comparing to traditional scouring. By considering the following parameters for cost analysis it is found that this process reduces 10-20% of total annual cost which adds a significant amount of profit to the companys annual turnover. Less chemical cost Energy saving Time saving Less water consumption Less weight loss of fabric Less dye loss Less effluent treatment cost
  • 10. 10 Less chemical cost: Cost of Traditional Scouring Chemicals %, g/l Rate Qty/100 kg fabric Cost/100 kg fabric Softening agent 0.5 140.46 0.4 56.18 Sequestering agent 0.3 207 0.24 49.68 Nonionic Surfactants 1.0 235 0.80 188.00 Dispersants 0.5 112 0.4 44.80 Caustic Soda 3.0 38 2.4 91.20 Stabilizer 0.3 107 0.24 25.68 Hydrogen Peroxide 2.5 42.88 2.0 85.76 Jet 0.1 235 0.08 18.80 Acetic Acid 1.0 60.5 0.8 48.40 Total Cost 608.50 Cost/kg 6.09 Courtesy: Sinha Knitting Ltd. (Dyeing Division)
  • 11. 11 Cost of Bio-Scouring Chemicals %, g/l Rate Qty/100 kg fabric Cost/100 kg fabric Softening agent 0.5 140.44 0.4 56.17 Soda Ash 0.4 27.67 0.32 8.85 Nonionic Surfactants 0.3 235 0.24 56.4 Scouring enzyme 0.8 258 0.64 165.12 Jet 0.7 235 0.56 131.6 Dispersants 0.5 112 0.40 44.8 Total Cost 462.94 Cost/kg 4.63 Courtesy: Sinha Knitting Ltd. (Dyeing Division) Energy saving: Time saving:
  • 12. 12 Less Water Consumption: Less weight loss of fabric: Duration Fabric reqd in traditional scouring (kg) Fabric reqd in bio scouring (kg) Fabric save (kg) Cost save ($) Per shift 4000 3920 80 400 Per day 12000 11760 240 1200 Per month 360000 352800 7200 36000 Annual 4320000 4233600 86400 432000 Courtesy: Northern Corporation
  • 13. 13 Less Effluent Cost: Norms of discharged Water After traditional scouring After bio scouring Reduction (%) Total Cost Reduction (%) pH 9.78 7.16 26.78 BOD 215 58 73.12 COD 283 179 36.74 31.55 TDS 1361 1317 3.23 TSS 13 12 13.3 DO 6.21 3.94 36.14 Courtesy: Northern Corporation 7. Environmental Perspective: The norms of discharged water after dyeing with traditional scouring and bio scouring can be furnished by the following way. It is an approximate data of Northern Corporation. Norms of discharged Water After traditional scouring After bio scouring Reduction (%) pH 9.78 7.16 26.78 BOD 215 58 73.12 COD 283 [18] 8. Better & more uniform affinity for dyes. 9. In the case of woven fabrics, the possibility to combine the desizing & bio-scouring steps in just one.
  • 14. 14 10. In the case of knitted fabrics, combining bio-scouring with bio-polishing using Cellulase, with a Jet or Overflow machine. [19] 11. Possibility of scouring of cotton even when blended with more delicate fibers. 12. It lowers yarn coefficient of friction. 13. It improves emerising and brushing properties. 14. It increases yarn elongation for improved weaving efficiencies. [20] 2.7 Enzymatic Bio-Finishing The uses of Cellulase in textiles permits the development of a new range of finishing & fashion effect industrial processes for fabrics & garments, with an absolutely environment-friendly approach. Bio-polishing or Bio-finishing with Cellulase is carried out both on pieces as well as made up & it can be carried out before dyeing or after dyeing also to give a sort of stone-wash effect. Matzyme BIO-F is a Cellulase enzyme that eliminates the dead/immature cotton whereas Matzyme DS is effective in de-pilling as well as surface hair removal. [21] 2.7.1 Bio-Polishing / Bio-Finishing Technique permit: Neutral bio-finishing agents comprise enzymes designed for bio-finishing under neutral conditions with excellent surface defibrillation. These enzymes impart a unique handle to the substrate. Further, the enzymes can produce high-quality denim garments under neutral process conditions helping protect the environment. [22] Acidic bio-finishing agents comprise enzymes engineered for bio-finishing under acidic conditions with excellent surface defibrillation. These enzymes impart a unique handle to the substrate by resulting in a clean look. They also help in disposition of other finishing agents uniformly across knitted fabrics. [23] Elimination of dead or immature cotton, of neps and surface hairiness. Natural" softening with an improvement of hand and drapability. Permanent prevention of reiterated fibrillation and pilling.
  • 15. 15 Increase in hydrophilic properties, particularly in the case of terry fabrics. Better cleanliness and brightness, as well as uniformity of dye. Better overall quality of the material. The possibility of creating finishing to suit new and original fashion effects. Use of an entirely environmentally friendly process. [24] 2.8 ENZYMATIC BIO-WASHING/BIO-STONING/BIO-FADING 2.8.1Stone-wash: This is done to achieve stone-wash effect to denims. Cellulase enzymes are natural proteins which are used in denim garment processing to get stone wash look on to the denim garments without using stones or by reducing the use of pumice stone. There are many limitations and drawbacks associated with stone washing process, which can be overcome by using new enzyme based washing technology. Cellulase attacks primarily on the surface of the cellulose fiber, leaving the interior of the fiber as it is, by removing the indigo present in the surface layer of fiber. Matzyme BIO-W is one such type of Cellulase enzyme that give excellent stone-wash effects. [25] 2.8.1.1 Some Examples 2.8.1.1.1 Acid Stone-Wash Enzymes The popularity of denim garments increased as new garment wet processes changed denim's look and feel from the hard, dark blue garments used as work wear into soft and smooth fashion items with an abraded look. Surprisingly, this look earlier achieved by using pumice stones. Nowadays, also can be attained using cellulase enzymes. Cellulases loosen the surface fibers of the denim garment so that mechanical action in a washing machine breaks the surface to remove the indigo dye, revealing the white core of the ring-dyed yarns. The most denim garments are "stonewashed" using Cellulases, either alone or in combination with a reduced amount of stones.
  • 16. 16 The Cellulases resulted in increased washing capacity for the power laundries, and reduced damage to garments as well as to washing machines, in addition to diminish environmental effects from pumice stone mining and disposal of used pumice. Acidic bio-fading agents comprise enzymes designed for bio-fading of denims under acidic conditions, which creates better contrast and an excellent bio-polishing effect. These agents also create a unique salt-and-pepper effect by using acidic bio-fading enzymes instead of harsh chemicals such as caustic. Advantages : 1) It offers versatility in process parameters 2) It gives high color contrast finish 3) It improves wash look and creates new looks 4) It reduces indigo back-staining 5) Optimal strength retention of fabrics/garments 6) It is compatible with most other processing aids, including nonionic wetting agents and dispersants, lubricants, pumice stones, and diatomaceous earth. 7) High degree of reproducibility and reliability 8) It is versatile which provides surface polishing, and softening with low enzyme dosages on a variety of cellulosic fabrics and garments. 9) It is very cost effective, easy in handling and works in an eco-friendly way [26] 2.8.1.1.2 Neutral Stone-Wash Enzymes The popularity of denim garments increased as new garment wet processes changed denim's look and feel from the hard, dark blue garments used as work wear into soft and smooth fashion items with an abraded look. Surprisingly, this look earlier achieved by using pumice stones. Nowadays, also can be attained using cellulase enzymes. Cellulases loosen the surface fibers of the denim garment so that mechanical action in a washing machine breaks the surface to remove the indigo dye, revealing the white core of the ring-dyed yarns. The most denim garments are "stonewashed" using Cellulases, either alone or in combination with a reduced amount of stones.
  • 17. 17 The Cellulases resulted in increased washing capacity for the power laundries, and reduced damage to garments as well as to washing machines, in addition to diminish environmental effects from pumice stone mining and disposal of used pumice. Neutral bio-fading agents comprise enzymes designed for bio-fading of denims under neutral conditions, which creates better contrast and an excellent bio-polishing effect. These enzymes impart a unique handle to the substrate. When used in combination with enzymatic desizing agents prior to the fading process, these enzymes usually deliver enhanced results [27] 2.8.2 Cellulase-wash This is done to achieve a wash down appearance on denim garments. This enzymes are selective only to the cellulose and will not degrade starch. Under certain conditions, their ability to react with cellulose will result in surface fiber removal (weight loss). This will give garments a washed appearance and soft hand. Matzyme BIO-G is especially designed for this Cellulase washing of denim garments with low back-staining that offers improved lustre. [28] 2.8.2.1 Some Examples 2.8.2.1.1 Acid Bio-Wash Enzymes The small fibers or fibrils protruding from the fabric render a fuzzy surface and the gradual entanglement of fibrils results in the formation of pills when a garment is worn and washed. Removal of surface fibrils improves fabric quality, keeping the garment in good form for a longer time. The use of Cellulases, combined with the synergistic action of the processing machines, is effective in removing the fibrils, leading to permanent improvement of fabric quality, including cleaner and smoother surface, softer hand and improved fabric drape. This treatment, called bio-polishing, is widely used today in garment processing and in batch processing of woven and knitted fabrics.
  • 18. 18 Advantages 1. It is versatile which provides surface polishing, and softening with low enzyme dosages on a variety of cellulosic fabrics and garments 2. It improves wash look and creates new looks 3. Low degree of indigo back-staining 4. Optimal strength retention of fabrics/garments 5. It works well in both high and low mechanical actions processing, which means good results are obtained in garment as well as in fabric bio-finishing 6. It is compatible with most other processing aids, including nonionic wetting agents and dispersants, lubricants, pumice stones, and diatomaceous earth 7. High degree of reproducibility and reliability 8. Maximized retention of fabric strength 9. It is very cost effective, easy in handling and works in an eco-friendly way 10. It gives high color contrast finish [29] 2.8.2.1.2 Neutral Bio-Wash Enzymes The small fibers or fibrils protruding from the fabric render a fuzzy surface and the gradual entanglement of fibrils results in the formation of pills when a garment is worn and washed. Removal of surface fibrils improves fabric quality, keeping the garment in good form for a longer time. The use of Cellulases, combined with the synergistic action of the processing machines, is effective in removing the fibrils, leading to permanent improvement of fabric quality, including cleaner and smoother surface, softer hand and improved fabric drape. This treatment, called bio-polishing, is widely used today in garment processing and in batch processing of woven and knitted fabrics. [30] 2.8.4 Advantages of enzyme washing i. Soft handle and attractive clean appearance is obtained. ii. No severe damage to the surface of yarn. iii. Simple process handling and minimum effluent problem. iv. Better feel to touch and increased gloss or luster. v. Prevents tendency of pilling after relatively short period of wear.
  • 19. 19 vi. Can be applied on cellulose and its blend. vii. Due to mild condition of treatment process is less corrosive. viii. More reproducible effect can be obtained. ix. It allows more loading of the garment into machines. x. Environmental friendly treatment. xi. Less damage to seam edges and badges. xii. Wear and tear of equipment is minimum due to absence of stone. xiii. Use of softener can be avoided or minimized. xiv. Easy handling of floor and severs as messy sludge of stones does not interfere. xv. Due to absence of stone, labor operation of stone removal is not required. xvi. Homogenous abrasion of the garments. [31] 2.9 ENZYMATIC PEROXIDE KILLING Matzyme VHK is a catalase enzyme derived from the submerged fermentation of a genetically modified strain of Aspergillus niger. It has been proven to be highly effective in catalyzing the decomposition of hydrogen peroxide into oxygen and water. 222 = 2 + 22 (Presence Of VHK) In textile wet-processing, this is often the most preferable method of hydrogen peroxide removal after bleaching step as the enzyme and the breakdown products are totally inert to reactive dyestuffs. In treating natural fibres composed of proteins, like silk and wool, protease can be used. On wool, with some protease base enzymatic preparations, interesting effects can be achieved which have some commercial importance, such as: 1) Softening and modification of hand characteristics. 2) Anti-pilling and surface cleaning. 3) Better drapability. 4) "Aged" look for garments of clothing. 5) Improved comfort.
  • 20. 20 In the case of anti-pilling treatment for wool woven and knitted fabrics, a protease has been launched on the market which can be used solely on pre-chlorinated wool. Unfortunately, treatments using only protease do not confer anti-felting properties on wool. 2.9.1 Table. 1 shows the possible uses of protease enzymes in wool Table :1 1) Limit the typical tendency of wool to shrink and felt 2) Solve dimensional stability problems 3) Provide machine wash characteristics for the fabric 4) Eliminate the negative properties emerging in fabric care processes (e.g. hygroscopic expansion) 5) Enhance the fabric coloring 6) Prevent the pilling effect after some finishing processes 7) Eliminate motes (in alternative to the conventional carbonizing methods) 8) Bio-scouring and Bleaching of wool 9) Possibility of enhancing the original fineness and softness characteristics of wool 10) Enhance the evenness of wool fabric fibers subjected to pre-dyeing treatments 11) Obtain stone-wash effects on yarn dyed fabrics, but above all on piece-dyed wool fabrics [32] 2.10 ENZYMATIC DEGUMMING Enzymatic degumming of silk using protease permits the Sericin to become hydrolyzed and at the same time other protein residues deposited by the silkworm. Through this enzymatic treatment, special effects are sought for softening and for the hand (e.g. peach-skin, draping, suede-like effects etc.) demanded by fashion or the market. It should, however, be noted that, while protease on silk can certainly give interesting and commercially valid results, they are still difficult treatments to carry out correctly in order to avoid irreversible damage. Recently a new oxido-reducing (Laccase) enzyme was also proposed for breaking the irreversible oxidative breaking of indigo which gives denim garments a
  • 21. 21 "cleaned" effect on back-staining (using low quantities) or bleaching (using higher quantities). Enzymology is however finding increasingly large space in the practice of preparing and finishing of textiles. [32] 2.11 Latest Development: Enzymatic Printing Process 2.11.1 New Method of Discharge Printing on Cotton Fabrics Using Enzymes Discharge printing is a method where the pattern is produced by the chemical destruction of the original dye in the printed areas. The discharging agents used can be oxidizing or reducing agents, acids, alkalis and various salts. But, most important methods of discharging are based Sulphoxylates formaldehyde & Thiourea dioxide. Recently, the environmental and industrial safety conditions increased the potential for use of enzymes in textile processing to ensure eco-friendly production. In Discharge printing, Sulphoxylate Formaldehyde (NaHS02.CH2O.2H20) is one of the powerful discharging agent used commercially, however, it is considerably toxic and evolves formaldehyde known as a human carcinogenic associated with nasal sinus cancer and nasopharyngeal cancer. In this part I have discussed about replacement of this hazardous chemical with eco- friendly enzymes in textile discharge printing. Enzymatic discharging printing carried out with Phenol oxidizing enzyme such as Peroxidase with hydrogen peroxide by selectively discharged reactive dyes from the cotton fabric at selected areas creating a printed surface. Textile discharging printing is the most versatile and important of the methods used for introducing design to textile fabrics. Considered analytically it is a process of bringing together a design idea, one or more colorants, and a textile fabric, using a technique for applying the colorants with some precision. Biotechnology has dramatically increased the scope for application of enzyme systems in all areas of textile processing. Enzymes can be tailored to implement specific reactions, such as decomposition, oxidation and synthesis, for a variety of
  • 22. 22 purposes. There is a growing recognition that enzymes can be used in many remediation processes to target specific purpose in textile industry. In this direction, recent biotechnological advances have allowed the production of cheaper and more readily available enzymes through better isolation and purification procedures. 2.11.2 Application of Enzymes in Discharging Printing The cotton samples shall printed with an enzyme printing paste using hand screen printing technique as required recipe. The printed cotton samples shall allow drying at ambient condition then it can leave in an oven for different Intervals of time and at different temperatures. Finally washing was carried out. 2.11.3 Disadvantages of Conventional Discharged printing method Formaldehyde content in conventional discharged printed fabric had observed beyond acceptable limit of OKO-Tex 100 standard (Skin contact: 75 ppm) (J. Gokul and P. Michael, 2006). By the way using Horseradish Peroxidase enzyme, formaldehyde liberation can be fully eliminated from discharge printed fabric. Tensile strength result of conventional printed fabric reveals slight increases in strength loss compare with Bio- discharge printed fabric. Abrasion resistance result also low in conventional printed fabric. Formaldehyde content in conventional discharged printed fabric is beyond acceptable limit. Fastness & absorbency results of fabric are same in both printed method (Karthi, et.al 2009). 2.11.4 Advantages of Enzymatic Discharge printing Elimination of formaldehyde Energy Saving Reduction of strength loss Environmental friendly
  • 23. 23 Bio-technology & enzyme application is inevitable tool in modern industry where environmental aspect plays critical role to sustain in the competitive market. Innovative method of using Horseradish Peroxidase & H202 formulation in discharge printing of textiles can carry out successfully with replacement of toxic discharging agent. Formaldehyde liberation can be fully avoided in this kind of Bio-discharge printing. [33] 2.12 DECOLORIZATION OF TEXTILE WASTE WATER Enzymes such as Laccase and manganese peroxidases can cleave aromatic rings. These have potential for destroying dyes though individual enzymes capable of breaking down one type of dye molecular structure may be blocked from attacking another dye structure. [34] 2.13 Effect of enzymatic finish on physical properties of naturally colored Cotton Enzymatic treatment increased the yarn count and cloth count of the naturally color linted cotton khadi fabric compared to control. There was decrease in thickness of the test samples on enzyme treatment. Decrease in cloth bending length and crease recovery was noticed in enzyme treated fabric samples. Color linted cotton khadi samples attained dimensional stability after enzyme treatment. Enzyme treated test sample showed decrease in tear strength. There existed a negative relation slip between cloth count and tear strength. Resistance to abrasion decreased on enzyme treatment in terms of percent increase in loss of thickness and mass/unit area.
  • 24. 24 Cloth thickness is directly proportional to abrasion resistance. Enzyme treated samples showed better drapability compared to control and naturally color linted fabric samples with enzymatic finish showed excellent resistance to pilling. [35] 2.14 Vision for industrial or white biotechnology in 2025(10) An increasing number of chemicals and materials will be produced using biotechnology in a more efficient and sustainable way. Biotechnology allows for an increasing eco-efficient use of renewable resources as raw materials for the industry. Biomass derived energy, based on biotechnology is expected to cover an increasing amount of our energy consumption. Green Biotechnology could make a substantial contribution to the efficient production of biomass raw materials. The action plan necessary to achieve this vision includes: 1) The development of a strategic research agenda and road map. 2) The removal of technical, economic, regulatory and implementation barriers. [36]
  • 25. 25 3. Conclusion Textile processing is a growing industry that traditionally has used a lot of water, energy and harsh chemicals. Starting from pesticides for cotton growing to high amounts of wash waters that result in waste streams causing high environmental burdens. As textile fibers are polymers, the majority being of natural origin, it is reasonable to expect there would be a lot of opportunities for the application of white biotechnology to textile processing. Enzymes natures catalysts are the logical tools for development of new biotechnology-based solutions for textile wet processing. Developments in genetic and protein engineering have led to improvements in the stability, economy, specificity and overall application potential of industrial enzymes. When all the benefits of using enzymes are taken into consideration, its not surprising that the number of commercial applications for enzymes is increasing every year. [37]
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