Bio Tech Textiles – Future Trend

Biotechnology defined as the application of living organisms and their components to industrial products and processes is not an industry in itself, but an important technology that will have a large impact on many different industrial sectors in the future. 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. Biotechnology a new impetus in the last few years has been the very rapid developments in genetic manipulation techniques (genetic engineering) 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 (genes) from one organism to another.

Biotechnology also offers the potential for new industrial processes that require less energy and are based on renewable raw materials. It is important to note that biotechnology is not just concerned with biology, but it is a truly interdisciplinary subject involving the integration of natural and engineering sciences. Biotechnology is like an enormous factory which not only provides other industries with innovative ideas, but also supplies the appropriate know-how. Now familiar with the application of modern biotechnology in medicine and agriculture: so-called red and green biotechnology. There is less general awareness of the white variety: the use of biotechnology for industrial applications. Cheese production, golden rice, the manufacture of insulin and interferon, biosensors, enzymes in detergents - these are all examples of biotechnology in action, a sector that is constantly growing and expanding into other industrial sectors, a true driving force of interdisciplinary applications. The current trend deals with the potential of biotechnology in the textile industry.

1. Introduction

Textile production involved the exclusive use of natural fibers: cotton, hemp, flax, etc. The invention of synthetic fibers in the 20th century broadened the application range of textile materials enormously. Great improvements have been made in technical textiles since the 1980s which now account for approximately 40 percent of the entire textile production. Therefore, their huge innovation potential makes them the driving force in the growing textile industry. Invention of Modern Fabrics specific interdisciplinary partnerships between the most diverse scientific fields enables the industry to combine several functionalities in one material. The new fabrics may be breathable, temperature-regulating, lightweight, shock-proof, water and dirt repellent and a lot more.

It is, in particular, this multifunctionality which broadens the application of these modern fabrics, which, apart from being used as clothing, can be used in car manufacture, space technology, agriculture or biomedical technology. Innovative materials are also found in the field of medicine and many applications are possible, ranging from tissue engineering to wound dressings and implants. In the field of biomedical technology, biologists and engineers cooperate closely and develop biomaterials and implants as well as methods enabling the regeneration of tissue, for example three-dimensional, shapeable fleeces in which the patients own cartilage cells can be grown.

New opportunities for modern textiles have also opened up in the treatment of wounds. In view of the growing number of elderly people and diabetics in modern society, the treatment of problematic wounds is a major application area of such textiles. Innovative medical textiles will no doubt play an important role in the treatment of wounds and skin in future. The integration of therapeutic substances turns textiles into innovative medical products.

Improvement of plant varieties used in the production of textile fibres and in fibre properties.
Improvement of fibres derived from animals and health care of the animals.
Novel fibres from biopolymers and genetically modified micro-organisms
Replacement of harsh and energy demanding chemical treatments by enzymes in textile processing
Environmentally 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 of adulteration and Quality Control of textiles
Waste management

2. Fibres and Biopolymers

Nature has provided us with textile fibres such as cotton, wool and silk but there is now the potential to harness biotechnology and produce new or modified fibres as well as improving the production yields of existing fibres. Cotton has the unfortunate characteristic of being vulnerable to many insects, and to maintain yields, these insects are managed with large amounts of pesticides. Cotton is also prone to infestation by weeds which thrive under the intense irrigation conditions that cotton needs throughout its growth cycle and cotton has poor tolerance to any of the herbicides in use today. It is not surprising, therefore, that biotechnology companies have focused their short term objectives on genetically engineering insect, disease and herbicide resistance into the cotton plant.

Longer term goals include the modification of fibre quality and properties (e.g. length and strength) leading to the development of high performance cottons. There is already a small market for naturally colored cottons but the colour range that has been developed using classical selection techniques is limited. The development of transgenic intensely coloured cottons (e.g. blues and vivid reds) could one day replace the need for bleaches and dyes.

Biotechnology is expected to have a very large impact on animal fibre production. A whole range of new technologies are now available including in vitro fertilization and embryo transfer, diagnostics, genetically engineered vaccines and therapeutic drugs. Genetic modification of sheep to resist attack from blowfly larvae by engineering a sheep that secretes an insect repellent from its hair follicles and 'biological wool shearing'. The latter technique relies on an artificial epidermal growth factor which when injected into sheep interrupts hair growth. A month later, breaks appear in the wool fibre and the fleece can be pulled off whole in half the time it takes to shear a sheep. There is also considerable research being carried out in several countries with the aim of producing finer and therefore more valuable wool's from sheep.

2.1. Novel Fibres

Novel fibre-forming biopolymers are now being manufactured using large-scale fermentation equipment. For example, the bacterial storage compound polyhydroxybutyrate (PHB) has been developed by Zeneca Bioproducts (formerly ICI Agricultural Division) and is produced under the trade name 'Biopol'. This high molecular weight linear polyester has good thermoplastic properties (melting point 180'C) and can be melt spun into fibres. Biocompatibility and biodegradability makes PHB fibres ideally suited for surgical use; sutures made from PHB are slowly degraded by the body's enzymes.

Zeneca is currently using Biopol in conventional plastics applications such as shampoo bottles. The price of the polymer is still considered too high for many fibre applications and ultimately Biopol might be produced by plants. Zeneca seeds are experimenting with a genetically engineered variety of rape which can synthesis Biopol. Synthetic fibres made from renewable sources of biomass are environmentally sustainable, and are becoming increasingly economically sustainable. Biodegradable synthetic polymers include novel fibres such as polyglycolic acid and polylactic acid, which are made from natural starting materials. Not all novel fibres are synthetic; they may also be naturally derived.

Some natural biological fibres come from basic materials found in nature, including:

Chitin  a type of sugar polymer found in crustaceans

Collagen  a type of protein found in animal connective tissue

Alginate  a type of sugar polymer found in certain bacteria
A prime example of a synthetic biomass fibre is Polylactic Acid
(PLA), which is made by fermenting cornstarch or glucose into lactic acid, and then chemically transforming it into a polymer fibre. With properties similar to other synthetic fibres, PLA based materials are durable with a silky feel, and may be blended with wool or cotton.

Figure .2. Schematic diagrams of the model describing the process of lead adsorption on cellulose/chitin beads:

2.2. Polylactic Acid (PLA)

PLA has potential applications in several areas, including the following:

Textiles  clothing, fashions, and upholstery

Agriculture  plant mats, tree nets, soil erosion control products

Sanitation  household wipes, diaper products

Medicine  disposable garments, medical textiles

PLA minimizes environmental waste, as it may be fully biodegraded by microorganisms under appropriate conditions into carbon dioxide and water. Unlike the non-renewable petroleum resources used to make traditional synthetic fibres, the supply of renewable corn biomass needed to make PLA is expected to surpass demand in the anticipated future. Biodegradable synthetic fibres and natural biological fibres may be used to make textiles for medical applications.

Other biopolymers currently in wound-healing applications include the polysaccharides chitin, alginate, dextrin and hyaluronic acid. Chitin and its derivative chitosan are important components of fungal cell walls although these polymers are, at present manufactured from sea food (shellfish) wastes. The use of intact fungal filaments as a direct source of chitin or chitosan fibre to produce inexpensive wound dressings and other novel materials. Tests carried out at the Welsh School of Pharmacy indicate that these products have wound healing acceleration properties. Wound dressings based on calcium alginate fibres have already been developed by Courtaulds and are marketed under the trade name 'Sorbsan'.

Present supplies of this polysaccharide rely on its extraction from brown seaweed's. However, a polymer of similar structure can also be produced by fermentation from certain species of bacteria. Dextran, which is manufactured by the fermentation of sucrose by Leuconostoc mesenteroides or related species of bacteria, is also being developed as a fibrous non-woven for speciality end-uses such as wound dressings. Additional biopolymers, not previously available on a large scale are now coming onto the market thanks to biotechnology. One such example is hyaluronic acid a polydisaccharide of D-glucuronic acid and N-acetyl glucosamine found in the connective tissue matrices of vertebrates and is also present in the capsules of some bacteria.

The original method of production by extraction from rooster combs was very inefficient requiring 5kg of rooster combs to provide 4g of hyaluronic acid. Fermentech, a British biotechnology company, is now producing hyaluronic acid by fermentation. The same amount of high quality purified hyaluronic acid can be obtained from 4 litres of fermentation broth as opposed to 5kg of rooster combs.

Two different biotechnological routes for the production of cellulose are under investigation in various laboratories throughout the world. Cellulose is produced as an extra cellular polysaccharide by a number of different bacteria in the form of ribbon-like micro fibrils. These can be used to produce moulded materials of relatively high strength. An alternative route to cellulose, still at a very early stage of development, concerns the in vitro cultivation of plant cells. It has already been demonstrated that cotton fibres can be produced in vitro by culturing cells of various strains of Gossypium.

The potential advantages of this route include a more uniform product displaying particularly desirable properties. Plant tissue culture can provide a steady, all year supply of products without climatic or geographic limitations free of contamination from pests. Another group of biopolymers of particular interest to biotechnologists are proteins because of the scope for utilizing the new genetic manipulation techniques. Thus genes for animal and plant proteins (e.g. collagen, various silks) can now be transferred into suitable microbial hosts and the proteins produced by fermentation. The US army is keen to develop spider silk as a high performance fibre for use in products such as bullet proof vests.

3. Enzymes

The mediation of chemical reactions by catalytic proteins (enzymes) is a central feature of living systems. Living cells make enzymes although the enzymes themselves are not alive and we can encourage living cells to make more enzymes than they would normally make or to make a slightly different type of enzyme (protein engineering) with improved characteristics of specificity, stability and performance in industrial processes. These enzymes usually operate under mild conditions of pH and temperature. Many enzymes exhibit great specificity and stereo selectivity.

With the notable exception of starch-size removal by amylases, scant attention has been given to the application of enzymes in textile processing. The preparation of certain textile fibres such as flax and hemp by dew-retting involves the action of pectolytic enzymes from various micro-organisms which degrade pectin in the middle lamella of these plant fibres. The use of isolated enzymes to remove fats and waxes, pectin's, seed-coat material and coloured impurities from loom state cotton and cotton/polyester fabrics, leading to a novel, low energy fabric-preparation process to replace scouring and bleaching.

Using existing commercial enzyme preparations due to the recalcitrant nature of some of the components and the process was found to be too slow and therefore uneconomic for current applications. One enzyme that is already being applied in textile processing for the removal of hydrogen peroxide prior to dyeing is catalase. The use of microbial enzymes can be expected to expand into many other areas of the textile industry replacing existing chemical or mechanical processes in the not too distant future. In contrast to textile processing there has been a dramatic increase in the use of enzymes in detergents since their introduction in the 1960's. Washing powders are referred to as biological because they contain enzymes.

Enzymes are now available that can degrade a wide range of stains and their use allows milder washing conditions at lower temperatures which both saves energy and protects the fabric. Recently it was discovered that cellulase enzymes could replace the pumice stones used by industry to produce 'stone-washed' denim garments. The stones can damage the clothes, particularly the hems and waistbands, and most manufacturers are now using the enzyme treatment. Another novel application for cellulase enzymes is in biopolishing, the removal of fuzz from the surface of cellulosic fibres which eliminates pilling making the fabrics smoother and cleaner-looking. A similar process using protease enzymes has been developed for wool.

More futuristic applications for enzymes are in the field of biotransformation. A biotransformation is defined as the biocatalytic transformation of one chemical to another. In practice, either intact cells, an extract from such cells or an isolated enzyme may be used as the catalyst system of a specific reaction. Although the concentration of individual enzymes in cells is typically less than 1 per cent this can now be increased using gene amplification techniques. It is not expected that the current production of bulk chemicals by oil-based processes will be replaced by biotransformation, at least in the foreseeable future. However, there are areas where biotechnology can be expected to compete with chemical synthesis. The requirement for optical activity of chemicals such as polymer precursors is likely to grow and here the biotransformation route has a particular edge over traditional chemical methods.

3.1. Cellulases and cellulose

Cellulases have had the most impact on textile processing in recent years. Current commercial applications include "biostoning", "biopolishing" and as laundering "brightners" of cotton fabrics. There is a fine balance between producing the desired effect and causing excessive damage to the fibres leading to an unacceptable loss in strength. The use of mono-component endoglucanase or endoglucanase-enriched cellulase complexes together with a high level of mechanical agitation can achieve the desired performance with only a limited loss of tensile strength. Most of this work had been done using woven cotton fabrics. Steaming increased the accessibility of the yarns to the enzymes. The resulting decrease in hairiness and tendency towards pilling was mainly attributed to endoglucanase activity.

4. Enzyme Biotechnology in Textiles

Through biotechnology, enzymes are used to treat and modify fibres during textile manufacturing, processing, and in caring for the product afterwards. Some applications include:

4.1. De-sizing of cotton

Untreated cotton threads can break easily when being woven into fabrics. To prevent this breakage, they are coated with a jelly-like substance through a process called sizing. However, after the threads have been woven into fabrics, the agents needed to further finish the material cannot adhere to the jelly-coated fabrics. Thus, the protective sizing agents must be removed by a process called de-sizing. Amylase enzymes are widely used in de-sizing, as they do not weaken or affect cotton fibres, nor do they harm the environment.

4.2. Retting of flax

Flax plants are an important source of textile fibres. Useful flax fibres are separated from the plant's tough stems through a process called retting. Traditional retting methods consume large quantities of water and energy. Bacteria, which may be bred or genetically engineered to contain necessary enzymes, can be used to make this a more energy efficient process.

4.3. Breakdown of hydrogen peroxide

When cotton is bleached, a chemical called hydrogen peroxide, which can react with other dyes, remains on the fabric. Catalase enzymes specifically break down hydrogen peroxide and may be used to remove this reactive chemical before further dyeing.

4.4. Biostoning and Biopolishing

Instead of using abrasive tools like pumice stones to create a stonewashed effect or to remove surface fuzz, cellulase enzymes may be used to effectively stonewash and polish fabrics without abrasively damaging the fibres.

4.5. Detergents

An enzyme allows detergents to effectively clean clothes and remove stains. They can remove certain stains, such as those made by grass and sweat, more effectively than enzyme-free detergents. Without enzymes, a lot of energy would be required to create the high temperatures and vigorous shaking needed to clean clothes effectively. Enzymes used in laundry detergents must be inexpensive, stable, and safe to use. Currently, only protease and amylase enzymes are incorporated into detergents. Lipase enzymes break down too easily in washing machines to be very useful in detergents. However, their stability is being studied and further developed through methods such as genetic screening and modification.

4.6. Textile Auxiliaries

Textile auxiliaries such as dyes could be produced by fermentation or from plants in the future, before the invention of synthetic dyes in the nineteenth century many of the colours used to dye textiles came from plants e.g. indigo and madder. Many micro-organisms 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 of 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.

Micro-organisms would therefore seem to offer great potential for the direct production of novel textile dyes or dye intermediates by controlled fermentation techniques replacing chemical synthesis which has inherent waste disposal problems (e.g. toxic heavy metal compounds). Another biotechnological route for producing pigments for use in the food, cosmetics or 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 a 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 percent of the dry weight of the roots. In tissue culture, pigment yields of about 15 percent of the dry weight of the root cells have been achieved.

5. Waste Management

Biotechnology can be used in new production processes that are themselves less polluting than the traditional processes and microbes or their enzymes are already being used to degrade toxic wastes. Waste treatment is probably the biggest industrial application of biotechnology. Specific problems pertaining to the textile industry include colour removal from dye house effluent, toxic heavy metal compounds and pentachlorophenol used overseas as a rot-proofing treatment of cotton fabrics but washed out during subsequent processing in the developed countries.

6. Innovative textiles by biotechnology

The textile industry explores new fields

Specific interdisciplinary partnerships between the most diverse scientific fields enable the industry to combine several functionalities in one material. The new fabrics may be breathable, temperature-regulating, lightweight, shock-proof, water and dirt repellent .This multifunctional which broadens the application of these modern fabrics, which, apart from being used as clothing, can be used in car manufacture, space technology, agriculture or biomedical technology.

6.1. Textiles in medicine

Innovative materials are also found in the field of medicine and many applications are possible, ranging from tissue engineering to wound dressings and implants. In the field of biomedical technology, biologists and engineers cooperate closely and develop biomaterials and implants as well as methods enabling the regeneration of tissue, for example resorbable, three-dimensional, shapeable fleeces in which the patients own cartilage cells can be grown. New opportunities for modern textiles have also opened up in the treatment of wounds. In view of the growing number of elderly people and diabetics in modern society, the treatment of problematic wounds is a major application area of such textiles. In Germany alone, there are approximately 2 million patients every year suffering from severe and chronic wounds. Innovative medical textiles will important role in the treatment of wounds and skin in future. The integration of therapeutic substances turns textiles into innovative medical products.

6.2. Intelligent technical textiles

An intelligent technical textile is another interdisciplinary example of innovative textiles used in the field of health and safety. These are textiles with integrated Microsystems used in clinical applications for measuring and monitoring of vital parameters such as blood pressure, pulse or breathing.

6.3. Virtual design of new textiles

In the past, the development of new textile structures for innovative areas of application was based on real experiments involving all kinds of different fibre shapes and mixtures. Nowadays, the properties of the material can be determined in advance using computers. Specific properties can be tested in order to develop the best product possible. Microstructure simulation technology enabling the properties of highly-complex materials and the design of new textiles for application in medicine and hygiene.

6.4. Nano Finishing

Nature has come up with surfaces to which dirt is unable to attach thanks to complex micro- and nanostructures. The self-cleaning effect of such extraordinary hydrophobic micro- and nanostructured plant surfaces was discovered and clarified by W. Barthlott at the University of Heidelberg in 1975. 'the lotus effect' of plants to textile surfaces, the lotus effect is huge not only for outdoor clothing and marquees, but also in medicine Another innovative material is polylactide (PLA), which can be found in biodegradable catering dishes or packaging and which has become a popular material among clothing manufacturers. Polylactides are a natural product, made from plant carbons. In contrast to nylon and polyester fibres made from non-renewable petrol, PLA uses carbon that is absorbed by maize plants during photosynthesis from the air.

The progress now being made in biotechnology and the current level of investment by governments and individual companies has enormous commercial implications for many sectors of industry in the years ahead. Biotechnology has already developed new products, opened up new markets, speeded up production and helped to clean up the environment. The textile industry was identified as a key sector where opportunities available from adapting biotechnology are high but current awareness of biotechnology is low.

The potential applications of conventionally produced textile materials in biotechnological processes. For example, downstream processing after fermentation accounts for at least 70% of production costs in biotechnology and there is the need for improved filtration and separation techniques. Hollow fibres and membranes which separate molecules according to size are finding increased application in this area.

6.5. Nature of white biotechnology

The various industrial applications of biotechnology have a number of things in common, both in terms of improved output and reduced environmental footprint. They can deliver some or all of the following benefits: