As the regulated quota system comes to an end in 2004 andthe free globalise market takes over, the priorities of textile manufacturersas well as consumer all over the globe are undergoing dramatic change. In thisglobal competition â€˜qualityâ€™ and â€˜eco - friendliness of process and productâ€˜plays key role. In this paper a brief introduction of research in variousfields of biotechnology to achieve the quality product through eco friendlyprocesses is given. Advances in the field of fibre production and modification,use of different enzymes in the textile processing, and waste management usingthe biotechnology is also discussed.
Textile industries are facing a challenging condition in the field ofquality and productivity, due to the globalization of the world market. Thehighly competitive atmosphere and as the ecological parameters becoming morestringent, it becomes the prime concern of the textile processor to beconscious about quality and ecology. Again the guidelines for the textileprocessing industries by the pollution control boards create concern over theenvironment-friendliness of the processes. This in turn makes it essential forinnovations and changes in the processes. As a result, the research anddevelopment strategies of the textile processors will be highly focused and thechallenges will force many changes in the textile industry. Biotechnology isone such field that is changing the conventional processing to eco friendlyprocessing of the textiles.
Biotechnology is the application of living organisms and their components toindustrial products and processes. In 1981, the European federation ofBiotechnology defined biotechnology as â€œintegrated use of Biochemistry,Microbiology, and chemical engineering in order to achieve the technologicalapplication of the capacities of microbes and cultured tissue cells. Definingthe scope of biotechnology is not easy because it overlaps with so manyindustries such as the chemical industry or food industry being the majors, butbiotechnology has found many applications in textile industry also, especiallytextile processing and effluent management. Consciousness and expectations forbetter quality fabric and awareness about environmental issues are twoimportant drivers for textile industry to adopt biotechnology in its variousareas.
2. BIOTECHNOLOGY IN TEXTILE PROCESSING
The major areas of application of biotechnology in textile industry are givenbelow:
Improvement of plant varieties used in the production of textile fibres and infibre properties
Â· Improvement of fibres derived from animals and health care of the animals
Â· Novel fibres from biopolymers and genetically modified microorganisms
Â· Replacement of harsh and energy demanding chemical treatments by enzymes intextile processing
Â· Environment friendly routes to textile auxiliaries such as dyestuffs
Â· Novel uses for enzymes in textile finishing
Â· Development of low energy enzyme based detergents
Â· New diagnostic tools for detection of adulteration and Quality Control oftextiles
Â· Waste managementÂÂ1, 2
3. Improvements in Natural fibres:
Biotechnology can play a crucial role in production of natural fibres withhighly improved and modified properties besides providing opportunities fordevelopment of absolutely new polymeric material. The natural fibres understudy are cotton, wool and silk.
Cotton continues to dominate the market of natural fibres. It has thegreatest technical and economic potential for transformation by technologicalmeans. Genetic engineering research on the cotton plant is currently directedby a two-pronged approach
Solving the major problems associated with the cultivation of cotton crop,namely the improved resistance to insects, diseases and herbicides, leading toimproved quality and higher yield.
The long â€“ term approach of developing cotton fibre with modified properties,such as improved strength, length, appearances, maturity and colour.
3.1.1 Transgenic cotton
Each year, thousands of research hours and hundreds of thousands of dollarsare spent to prevent cotton from caterpillars that love to eat cotton. Cottongrowers fight to produce a saleable product using pheromones (insects matinghormones) and monitoring. Use of excessive pesticides is posing serious threatsto the green image of cotton.
After years of research, a completely new kind of tool is available for cottongrowers to ward off the pink bollworm, one of the major cotton pests. About tenyears ago, Monsanto scientists obtained a toxin gene from the soil bacteriumcalled Bt (which is the nickname for Bacillus thuringiensis) and inserted it intocotton plants to create a caterpillar-resistant variety. The gene is DNA thatcarries the instructions for producing a toxic protein. The toxin killscaterpillars by paralyzing their guts when they eat it. Plants with the Bttoxin gene produce their own toxin and thus can kill caterpillars throughoutthe season without being sprayed with insecticide. Because the toxin is lethalto caterpillars but harmless to other organisms, it is safe for the public andthe environment.
Monsanto registered their Bt gene technology for transgenic cotton under thetrademark Bollgard and authorized selected seed companies to develop cottonvariety carrying the patented gene.
More stable, long lasting and more active Bts are now being developed for thesuppression of loopers and other worms in cotton. Insect resistance is alsobeing developed using a â€˜wound- inducible promoterâ€˜ gene capable of deliveringa large but highly localized dose of toxin within 30-40s of an insect biting.
3.1.2 Coloured cotton
Developments of fibres containing desirable shades in deep and fast colourswould change the face of the entire processing industry. Coloured cottons arealso being produced not only by conventional genetic selection but also bydirect DNA engineering.
Although several naturally coloured cotton varieties have been obtained bytraditional breeding methods, no blue variety exists. As blue is in greatdemand in the textile industry, particularly for jeans production, syntheticfabric dyes are used. However, the ingredients of these synthetic dyes areoften hazardous and their wastes are polluting.
Additionally, they take time and energy to work into the cloth. Natural bluecotton does not have these disadvantages and, therefore has great marketpotential. The genetic engineers plan to insert into production of blue dye,until a cheaper synthetic method is discovered. By 2005, Monsanto hopes to havethis blue-coloured cotton commercially available.
3.1.3 Hybrid cotton
Another major breakthrough has been the ability to produce cotton containingnatural polyester, such as polyhydroxybutyrate (PHB), inside their hollow core,thereby creating a natural polyester/cotton fibre. About 1% polyester contenthas been achieved and it has led to 8-9% increase in the heat retention offabrics woven from these fibres. Other biopolymers, including proteins, mayalso be introduced into cotton core in a similar manner.
These customized fibres will be tailored to the need of the textile industry.New properties may include greater fibre strength, enhanced dyeability,improved dimensional stability, reduced tendency for shrinking and wrinklingand altered absorbency. Greater strength will allow higher spinning speeds andimproved strength after wrinkle-free treatments. Improved reactivity will allowmore efficient use of dyes. Thus reducing the amount of colour in effluents. Toreduce the waste generated during scouring and bleaching processes, it would beinteresting to have fibres with less of pectins, waxy materials and containingenzymes that can biodegrade environmental contaminants. These fibres would beplaced in filters through which contaminated water is passed.
4. NOVEL FIBRES:
The use of biotechnology has the potential of control and specificity inpolymer synthesis which is difficult, if not impossible, to achieve in chemicalsystems. New materials produced using advanced biologically â€“ based approachesrepresent the textiles of the future.
4.1 Protein Polymers:
Biological systems are able to synthesize protein chains in which molecularweight, stereochemistry, amino acid composition and sequence are geneticallydetermined at the DNA level. A current area of investigation is to understandthose features of protein polymers that confer high tensile strength, highmodulus and other advantageous properties. Once those features are understood,the tools of biotechnology will make possible entirely new paradigms for thesynthesis and production of engineered protein polymers. If they can be madeeconomically viable, these new approaches will help to reduce the dependence onpetroleum and furthermore will enable the production of materials that arebiodegradable. Use of transgenic plants for large-scale production of these andother synthetic proteins is being explored.
Efforts in biosynthesis have been directed towards the preparation of preciselydefined polymers of three kinds (1) natural proteins such as silks, elastins,collagens and marine bioadhesives, (2) modified versions of these biopolymers,such as simplified repetitive sequence of the native protein, and (3) syntheticproteins designed de novo that have no close natural analogues. Although suchsyntheses pose significant technical problems, these difficulties have all beensuccessfully overcome in recent years. Using this technology, a whole new classof synthetic proteins with advanced properties, known as bioengineeredmaterials, is being created.
4.1.1 Spider silk:
Spider dragline silk is a versatile engineering material that performs severaldemanding functions. The mechanical properties of dragline silk exceed those ofmany synthetic fibres. Dragline silk is at least five times as strong as steel,twice as elastic as nylon, waterproof and stretchable. Moreover, it exhibitsthe unusual behavior that the strain required to cause failure actuallyincreases with increasing deformation.
4.2 Other New Fibres Sources:
There are many more biopolymers, of particular interest in sanitary and woundhealing applications, which include bacterial cellulose and the polysaccharidessuch as chitin, alginate, dextran and hyaluronic acid. Some of these arediscussed below:
4.2.1 Chitins and Chitosans:
Chitins and chitosans both can form strong fibres. Chitin is found in theshells of crustaceans, such as crab, lobster, shrimps etc. Resemblingcellulose, the chitin consists of long linear polymeric molecules of beta-(1-4) linked glycans. The carbon atom at position 2, however, is aminated andacetylated. Fabrics woven from them are antimicrobial and serve as wounddressing products and as anti-fungal stockings. Chitosan also has promisingapplications in the field of fabric finishing, including dyeing and shrinkproofing of wool. It is also useful in filtering and recovering heavy andprecious metals and dyestuffs from the waste streams.
Wound dressing based on calcium alginate fibres are marketed by Courtauldsunder the trade name â€˜Sorbsanâ€™. Present supplies of this polysaccharide rely onits extraction from certain species of bacteria. Dextran, which is manufacturedby the fermentation of sucrose by Leuconostoc mesenteroides or related speciesof bacteria, is also being developed as a fibrous nonwoven for specialty enduses such as wound dressings. Additional biopolymers, not previously availableon a large scale, are now coming into the market, thanks to biotechnology.
4.2.2 Bacterial cellulose:
Cellulose produced for industrial purposes is usually obtained from plantssources or it can be produced by bacterial action. Acetobacter xylinium is oneof the most important bacteria for cellulose production as sufficient amountscan be produced which makes it industrially viable. Cellulose produced byAcetobacter, which has the ability to synthesize cellulose from a wide varietyof substrates, is chemically pure and free of lignin and hemicellulose.Cellulose is produced as an extra cellular polysaccharide in the form of ribbonlike polymerization, high tensile strength and tear resistance and highhydrophilicity that distinguishes it from other forms of cellulose. Thisbacterial cellulose is being used by Sony Corporation of Japan in acousticdiaphragms for audio speakers. They are also being used in the production ofactivated carbon fibre sheets for absorption of toxic gas and as thickeners forniche cosmetic applications. In medical field, because of the hydrophilic andmechanical properties of bacterial cellulose, it is used temporarily as skinsubstitute and in wound healing bandages.
4.2.3 Corn fibre:
An entirely new type of synthetic fibre derived from a plant is Lactron. Thisenvironment â€“ friendly corn fibre was jointly developed by Kanebo Spinning andKanebo Gohsen of Japan. Lactron, the polylactic acid fibre is produced from thelactic acid obtained through the fermentation of corn starch. Strengthstretchability and other properties of Lactron are comparable to those ofpetrochemical fibres such as nylon and polyester. As the material is compatiblewith human body, it is being used for sanitary and household applications. Inaddition to clothing the company is also promoting its non-clothingapplications, e.g. construction, agricultural, papermaking, auto seat coversand household use.
The energy required for production of corn fibre is low and the fibre isbiodegradable. Moreover, no hazardous gases are created when it is incineratedand the required calories for combustion are only one-third or half of thoserequired by polyethylene or polypropylene. It safely decomposes into carbondioxide, hydrogen and oxygen when disposed of in soil. Lactron is beingmarketed in various forms such as woven cloth, thread and non-woven cloth.
4.2.4 Polyester fibres:
It has been known since 1926 that certain polyesters are synthesized andintra-cellulose deposited in granules by many micro-organism. Some of thesematerials have been formed into fibres. Polyhydroxybutyrate (PHB) is an energystorage material produced by a variety of bacteria in response to environmentalstress. It is being commercially produced from Alcaligenes eutrophus by ZenecaBioproducts and sold under the trade name Biopol.
As PHB is biodegradable, there is considerable interest in using it forpackaging purposes to reduce the environmental impact of human garbage. Thus itis already finding commercial application in specialty packaging uses. Becauseof its immunological compatibility with human tissue, PHB also has utility inantibiotics, drugs delivery, medical suture and bone replacement applications.
The development of biocidal fabrics was based on the idea of activatingtextiles with reactive chemicals to impart desirable properties. The latestresearch however is aimed at producing fabrics containing geneticallyengineered bacteria and cell strains to manufacture the chemicals within thetextiles thereby making the chemical stores within the fabrics theself-replenishing materials.
A collaborative project is on between the textile science research team atUniversity of Massachusetts, Dartmouth and the bio-engineers at Harvard medicalto carry out research leading to the production of a class of fabrics withspecial properties called biofabrics. Biofabrics will contain micro-fabricatedbio-environments and biologically activated fibres. These fabrics will havegenetically engineered bacteria and cells incorporated into them that willenable them to generate and replenish chemical coatings and chemically activecomponents.
Niche applications for bio-active fabrics exist in the medical and defenseindustries, e.g. drug producing bandages or protective clothing with highlysensitive cellular sensors, but biofabrics may form the basis of a whole new lineof commercial products as well e.g. fabrics that literally eat odours withgenetically engineered bacteria, self â€“ cleaning fabrics, and fabrics thatcontinually regenerate water and dust repellents.
For such an approach to be successful, technologies will have to be developedto micro-fabricate devices able to sustain cellular or bacterial life forextended periods, exhibit tolerance to extremes of temperature, humidity andexposure to washing agents, as well as tolerance to physical stress on the fabricssuch as tension, crumpling and pressure2.
6. ENZYMES IN TEXTILE FINISHING:
Textile finishing sector requires different chemicals, which are harmful to theenvironment. Sometimes they may affect the textile material if not usedproperly. So instead of using such chemicals we can use the enzymes. Thefinishing of denim garments has been revolutionized by application of enzymes.Enzymes are very specific in action when they are used under the requiredconditions. The processes in which enzymes can be used are desizing, scouring,bleaching, biowashing, degumming etc.
Fig : Enzymes in Textile processing
Amylase, pectinase, and glucose oxidase are enzymes used for desizing,scouring, and bleaching respectively in enzymatic preparation processes. Desizedsamples show completely size removal using amylase enzyme. Samples scoured withpectinase are immediately and uniformly wet. Amount of pectin and othersubstances left on scoured samples from both conventional and enzymaticprocesses were measured along with sample strength and whiteness index. Samplesbleached with glucose oxidase obtain whiteness index 15-20 degree improvementwith low strength loss. Conventional preparation of cotton requires highamounts of alkaline chemicals and consequently, huge quantities of rinse waterare generated. An alternative to this process is to use a combination ofsuitable enzyme systems. Amyloglucosidases, Pectinases, and glucose oxidaseshave been selected that are compatible concerning their active pH and temperaturerange. A process has been developed that allows the combination of two or allthree preparation steps with minimal amounts of treatment baths and rinsewater. Whiteness, absorbency, dyeability and tensile properties of the treatedfabrics have been evaluated.
The use of biocatalyst in the textile industry is already state of the art inthe cotton sector. Research and development in this sector is primarilyconcentrating on:
- Optimizing and making routine the use of technical enzymes in processes thatare already established in the textile industry today.
- Replacing established conventional processes with the aid of new types ofenzymes, particularly from extremophile micro-organisms, under stringentconditions (temperature of surfactant or organic components etc)
- Preparing enzyme-compatible dyestuff formulations, textile auxiliary agentsand chemical mixtures.
- Producing new or improved textile product properties by enzymatic treatment.
- Providing biotechnological dyes and textile auxiliary agents, which aresuitable for industrial use, and can possibly be synthesized in-situ (i.e.on-line for the application process).
6.1 Extremophile Micro-Organisms:
Numerous micro-organisms have learnt to live in very different and difficultenvironmental conditions, e.g. in high temperatures, in acid and alkalineconditions and in the presence of salt concentrations. These extremophilemicro-organisms live in the most inhospitable and unspoilt environments onearth. Where other micro-organisms do not exist, they are to be found in thedeepest oceans under pressures of more than 100 bar, in hot volcanic sources atover 100 C in cold regions at temperatures around freezing point, in salt lakes(up to 30% salt concentration) and also in surroundings with extreme pH values(pH <2,> 9). The cell components (enzymes, membranes) of extremophile areoptimally adapted to extreme environmental conditions, and have characteristics(stability, specificity and activity), which make them interesting forbiotechnological application.
At the Hamburg-Harburg (D) University of Technology, a comprehensive screeningprogrammed for isolating exremophile micro-organisms (like starch, proteins,and hemicellulose for example) has been implemented which is able to produceenzymes for breaking down biopolymers, alkanes, polyaromatic carbohydrates(PAK) plus fats and oils. Within the framework of these studies, a range ofbiotechnologically relevant enzymes like amylases, xylanases, proteases,lipases and DNA polymerases for example have been enriched and characterized.
6.2. Conversion Of Natural Polymers By Extremozymes:
Starch is one of the most important biopolymers on this earth. Themacromolecule built up from glucose units, plays an outstanding role in thefood industry under the collective concept â€œmodified starchâ€ this is found inmany foods. Amylases and branching enzymes for example are used for modifyingstarch. With the aid of thermostable starch-modifying enzymes, starch finishingcan be carried out more purposefully and efficiently, since for example thespace-time yield at high temperatures is significantly better due to improvedstarch solubility. Thermo-alkali-stable enzymes (active at pH >8 and 600C)are used in washing and harness rinsing agents in order to remove tenacious starchaccumulations with simultaneous reduction in detergent quantity.
6.3. Cyclising Enzymes:
So-called cylodextrins can be produced from starch with the aid of cyclisingenzymes (cyclodextringlycosyltransferase, CGTase) from the recently isolatedthermoalkaliphile bacterium Anaerobranca gottschalkii. Hydrophobic activesubstances or volatile aromas can be encapsulated in these cyclodextrins.Cyclodextrins were isolated by Villiers as early as 1891. In those days,cyclodextrins were regarded as curiosities of no technical value.
The properties of cyclodextrins have been altered by chemical change(derivatives). The target of much research work is to fix a reactivecyclodextrin derivative on cellulosic or protein fibres by forming a newchemical bond on the fibre. The molecules have a hollow space, which issuitable for absorbing diverse substances like perfume for example. Manyapplication possibilities and effects arise out of this complexing like forexample:
-Increased water solubility
-Change of rheological characteristics
-Stabilization against UV radiation, thermal disintegration, oxidation andhydrolysis
-Reduction of unpleasant smells
-Absorption of microbe-eliminating products
6.4. Cellulose From Extremophile Micro-Organisms:
Cellulose is also a biopolymer built up of glucose units. It forms theframework of higher plants and is an important resource in the textileindustry. The use of cellulases in detergents leads to colour revival (colourdetergent) and the improved removal of vegetable soiling. Cellulases are alsosuccessfully used in â€˜biostoningâ€™. In contrast to conventional cellulases,which are obtained from mesophilic fungi as a rule, cellulose-hydrolyzingenzymes from extremophile micro-organisms have the advantage of being capableof use even at high temperatures and pH values.
6.5 Xylanolytic enzymes:
Xylanolytic enzymes form another group. Xylan is heterogeneous molecule (basiccomponent: xylose sugar), which makes up the largest proportion of thepolymeric vegetable cell wall component hemicellulose. Xylanophilemicro-organisms have enormous biotechnological potential. Thermobile xylanasesare already being produced on an industrial scale today, and are used as fodderand food additives. In past years, interest in xylanases was concentrated particularlyon enzymatic paper bleaching. Current studies have shown that the enzymatictreatment of paper is an ecologically and economically sound alternative to thehitherto employed chlorine-based bleaching process.
Enzymes which can for example destroy the coloured attendant substances ofcotton are of interest to the textiles industry. The quantity of caustic sodaand salt required in peroxide bleaching could be reduced by this type ofenzymatic bleaching.
Reuse of the bleaching liquor after hydrogen peroxide bleaching is alreadypossible today by using the enzyme â€˜catalaseâ€™ after bleaching. This enzymedestroys excess hydrogen peroxide, making use of the bleaching liquor for otherfinishing stages possible.
Windel Textil GmbH & Co. (D) already uses the so-called â€˜Bleach-Cleanupâ€™process, in which bleaching agent residues are removed from textiles, resultingin a reduction of energy, time and water-intensive washing operations at hightemperatures.
Research projects at the German Wool Research Institute (DWI) in Aachen (D) aredevoted to the use of enzymes in wool processing, including the removal ofvegetable residues from the wool, increasing the degree of whiteness, improvinghandle, improving dyeability by increasing intensity of colour and for felt-freefinishing.
Already interesting in practice is the felt-free finishing of wool. An enzymenot previously employed in the textile industry modifies the scale-like surfaceof wool fibres preventing felting. The enzyme â€˜Lanazymâ€™ has hitherto been usedonly in discontinuous batch processing.3
7. DECOLOURISATION OF DYES BY USING BIOTECHNOLOGY:
The synthetic dyes are designed in such a way that they become resistant tomicrobial degradation under the aerobic conditions. Also the water solubilityand the high molecular weight inhibit the permeation through biological cellmembranes. Anaerobic processes convert the organic contaminants principallyinto methane and carbon dioxide, usually occupy less space, treat wastescontaining up to 30 000 mg/l of COD, have lower running costs and produce lesssludge4. Azo dyes are susceptible to anaerobic biodegradation but reduction ofazo compounds can result in odour problems. Biological systems, such asbiofilters and bioscrubbers, are now available for the removal of odour andother volatile compounds. The dyes can be removed by biosorption on applepomace and wheat straw5. The experimental results showed that 1 gm of applepomace and 1 gm of wheat straw, with a particle size of 600Âµm, were suitableadsorbents for the removal of dyes from effluents. Apple pomace had a greatercapacity to adsorb the reactive dyes taken for the study compared to wheatstraw.
7.1 Decolourization Of The Dye House Effluent Using Enzymes:
The use of lignin degrading white-rot fungi has attracted increasingscientific attention as these organisms are able to degrade a wide range ofrecalcitrant organic compounds such as polycyclic aromatic hydrocarbons,chlorophenol, and various azo, heterocyclic and polymeric dyes. The majorenzymes associated with the lignin degradation are laccase, lignin peroxidase,and manganese peroxidase. The laccases are the multicopper enzymes, whichcatalyze the oxidation of phenolic and non-phenolic compounds.
However, the substrate of the laccases can be extended by using mediators suchas 2, 2â€™-azoinobis-(3-ethylthiazoline-6-sulfonate), 1-hydroxybenzotriazole. Thefollowing fungi have been used for laccase production and for thedecolourization of synthetic dyes, Trametes Modesta, Trametes Versicolour,Trametes Hirsuta, and Sclerotium Rolfsii 6 From the results obtained it wasclear that Trametes Modesta laccase showed the highest potential to transformthe textile dyes into colourless products. The rate of the laccase catalyzeddecolourization of the dyes increases with the increase in temperature up tocertain degree above which the dye decolourization decreases or does not takeplace at all. The optimum pH for laccase catalyzed decolourization depends onthe type of the dye used. Dyes with different structures were decolourized atdifferent rates. From these results it can be concluded that the structure ofthe dye as well as the enzymes play major role in the decolourization of dyesand it is evident that the laccase of Trametes Modesta, may be used fordecolourization of textile dyestuffs, effluent treatments, and bioremediationor as a bleaching agent.
Another study carried out by E. Abadulla et al, has shown that the enzymesPleurotus ostreatus, Schizophyllum Commune, Sclerodium Rolfsii, TrametesVillosa, and Myceliophtora Thermiphilia efficiently decolourized a variety ofstructurally different dyes. This study also shows that the rate of reactiondepends on the structure of the dye and the enzyme7.
Activated sludge systems can also be used to treat the dyehouse effluents. Butthe main difficulty with activated sludge systems is the lack of true contacttime between the bacteria of the system and the suspended and dissolved wastepresent. Immobilized microbe bioreactors (IMBRs) address the need of increasedmicrobial/waste contact, without concomitant production of excessive biosolids,through the use of a solid but porous matrix to which a tailored microbialconsortium of organisms has been attached. This allowed greater number oforganisms to be available for waste degradation without the need of a suspendedpopulation and greater increased contact between the organisms and the waste inquestion8.
The advent of biotechnological applications in textile processing widens thealready existing wide horizons to produce aesthetically colourful magnanimousand ecologically friendly textiles, ringing in a new era of synergeticapplication of life sciences. As of today the huge textile industry is open towelcome the immense possibility of the various biotechnological applicationslimited by the limitations of being eco friendly and not harming either thefood web or the life cycle of any other living creature. Such awareness isgradually metamorphosing a tool that could be intelligently used to meet the demandof our fashion trends.
Enzymes, bacteria and insects could be biologically modified into a fashionpromoter if engineered with great caution. A major breakthrough in the textileindustry is eagerly awaited through these biotechnological applications.
Biotechnology, Edited by H. J. Rehm and G. Reed
Biotechnology application in textiles industry, Deepti Gupta, Indian Journal ofFibres & Textile Research Vol.26, March-June 2001.
Biotechnology: process and products, Andrea Bohringer, Jurg Rupp, InternationalTextile Bulletin, June 2002.
The Biotechnology Approach to Colour Removal from Textile Effluent, by NicolaWillmott et al. J of Soc. Of Dyers and Col., 1998, 114, 38-41.
Removal of dyes from a synthetic textile dye effluent by Biosorption, by T.Robinson, et al, Water Research, 36, 2002, 2824-2830.
Decolourization of textile dyes by laccases, by G. S. Nyanhongo, et al, WaterResearch, 36, 2002, 1449-1456.
Enzymatic decolourization of Textile Dyeing Effluents, by E. Abadulla et al,Textile Res. J. 70 (5), 2000, 409-414
Improving Bio-treatment For Textile Waste Decolourization, by Caroline A.Metosh et al, American Dyestuff Reporter, July/August19