Thousands of years back if you wanted to buy clothes to cover yourself it wouldn't have been possible. Most likely you would have had to make the cloth yourself by cutting hemp, make the stem soft by retting and extract the fibers from it and use those fibers to weave a cloth all by yourself. This was certainly biotechnology at work, but of course it wasn't called as such in those days.

Even otherwise nature provides us with a classic example of an all natural fabric fiber namely silk which is a natural protein fiber from the cocoons of the larvae of the mulberry silkworm Bombyx mori. Therefore, there had always been a correlation between textile fibers and biotechnology.

Biotech methods to make textile fibers

In modern times, basically there are two different biotech methods of making new kind of textile fibers. One method is to use suitably engineered genes to make monomeric protein molecules. The next step is to isolate the protein monomers and draw them into fibers.

The other method is to modify fibers by expressing other proteins internally by trangenesis. Using this method, cotton fiber with increased strength and colored cottons with the deep blue tinge and vivid red color as used for making denims have been successfully created. Research is also underway to make a special blend of natural polyester-cotton by inducing polyhydroxybutyrate (natural polyester) to grow within the cotton fiber.

Before we go any further, it is essential to have an understanding of what constitutes a textile product?

A textile is made up of fibers (giant molecules called polymers). Polymers in turn are several molecules hooked up to form long chains and the repeating units in this chain are called monomers. So these monomers join to form polymers due to addition or condensation reactions, as for example nylon which is a condensation polymer.

How biotechnology helps in textile manufacturing processes

Today biotechnology has facilitated the use of process enzymes in almost all stages of textile processing, starting from pre-treating, fiber preparation, fabric preparation to the finishing stage.

Preparing the fiber

For instance consider linen which is a cellulose fiber made from the flax plant. Conventionally they are separated from the stems by retting and now enzymes are used to aid this retting process and this gives even quality linen fibers

Similarly the removal of vegetable matter from wool (carbonization process) that is conventionally carried out using strong acid and mechanical crushing can now be done using enzymatic degradation processes

Preparing the fabric

Amylase enzymes have been consistently used for desizing processes but now more temperature stable enzymes have been developed that is related to different fabric types and sizes. Pre-bleach of cotton that has to be dyed a pale or medium shade is done using catalase enzymes to breakdown residual hydrogen peroxide

Currently these enzymes used in textile wet processing as part of fabric preparation work under benign conditions at low temperature and obviate the need for organic solvents. Examples are amylase to hydrolyze starch for desizing; cellulose to hydrolyze cellulose as in wool carbonization; protease to hydrolyze proteins; catalase to hydrolyze hydrogen peroxide; and laccase to decolorize indigo as in bio-bleaching of indigo in denim.


Textile Finishing


In conventional stone washing a tumbling machine with abrasive pumice stones removes dyestuff particles from the fabric surface. Now cellulase enzymes can work through cotton fibres and the results are better than in conventional stone washing besides being much softer on the cloth.

Sometimes the dictates of fashion requires that a particular fabric must have a worn out look although it is a new fabric. This fashion requirement can be had by stonewashing in a tumbled bath with abrasive stones or using enzymes such as cellulase in combination with pumice stones as for example in the case of denims.

Protease enzymes such as made by Novo are used for wool finishing treatments as they give the fabric softness and better surface appearance and on silk garments for giving that sand washed effect. After printing on textiles, protease enzymes are used to remove the gums that are present in the printing substances.


New Fibers

Biotechnology helps produce new textile fibre materials as well. For example 'Biopol' is PHB produced by bacterial fermentation of a sugar feed stock. Other fibers such as Polylactates and polycaprolactones have potential for use in textiles, especially in medical use. Sometimes it is the combination of biotechnology and nanotechnology that has resulted in the creation of new fibers as for example the fiber resulting from the bonding of PVA polymer with carbon nanotubes.

Now by genetically engineering a goat embryo with spider DNA, goats can be made to produce milk containing spider silk. Spider silk is made of a polymerized protein fibroine and it has tremendous tensile strength. These fibers retrieved from the goat milk are reportedly even stronger than Kevlar (a brand of strong synthetic fiber) and so could be used to make bullet proof vests.


Biotechnology based dyestuff

Before synthetic dyes came on the scene, colors for dyeing textiles came from plants and lichens. But synthetic dyes are associated with very difficult effluent disposal problems. Therefore biotech oriented dyestuff is increasingly being researched for use in the making of textiles. Certain micro fungi pigments are anthroquinone derivatives resembling vat dyes.

Certain fungal strains similar to Phoma herbarum are known to produce magenta pigment and there is research evidence to prove that microorganisms could be used to color textiles. Similarly bacterial forms of indigo pigments could find future in textiles.

Conclusion

One of the benefits in using enzymes in textile industry is that it has helped reduce the quantum of water required for different processes.

But some of the difficult problems in textile industry, such as the disposal of effluents that contain dyestuff need to be resolved, so in future enzymes could be doing the job of degrading dyestuff as part of effluent treatment process. As you can see, biotechnology finds wide application in textiles and this trend is likely to further consolidate in future. This is hardly surprising because the origin of textiles itself can be traced to biotech processes thousands of years ago

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