Why Cellulase Important in Stone Washing | WorldOfChemicals

Why Cellulase Important in Stone Washing!

Category : General Chemicals
Published by : Data Research Analyst, Worldofchemicals.com

Jeans is typically comprised of denim or dungaree cloth. Often the term jeans generally refers to a particular style of pants, called blue jeans, which were invented by Jacob W. Davis in partnership with Levi Strauss & Co. in the year of 1871. It was originally designed for cowboys and miners, later jeans became popular in the 1950s among teenagers, especially members of the greaser subculture.

Jeans were a most prevalent fashion item in the 1960s Hippie subculture and they continued to be popular in the 1970s and 1980s youth subcultures of punk rock and heavy metal. Historic brands of jeans include Levi's, Lee, and Wrangler.

In the 2010s, jeans came in various fits, including skinny, tapered, slim, straight, boot cut, cigarette bottom, narrow bottom, bell bottom, low waist, anti-fit, and flare.

Traditionally, jeans were dyed to a blue color using natural indigo dye. Most denim is now dyed using synthetic indigo.

 

Stonewashing process is one of the textile manufacturing processes used to give a newly manufactured cloth garment a worn-in or worn-out appearance. The stonewashing process can benefit in various methods like to increase the softness and flexibility of stiff and rigid fabrics such as canvas and denim jeans.

The process typically uses large sized stones to roughen up the jeans fabric being processed. Then the garments are placed in large-sized equipment called horizontal industrial clothes washer which is also filled with large stones. As the wash cylinder start rotating, the cloth fibers are repeatedly pounded and beaten as the tumbling stones ride up the paddles inside the drum and fall back down onto the fabric.

Stonewashed jeans are jeans that have been treated to produce a trendy faded, worn appearance. This is usually accomplished either by washing the jeans with a pumice stone in a rotating drum, or also by using chemicals to create the appearance without the use of a rotating drum.

The reduction of pumice stone usage and the growing disposal of its chemically-tainted residue triggered a search for novel methods made to rethink about these process and thereby notably the use of alternative abrading materials or machines and the use of cellulase enzymes is came to picture. Stonewashed jeans were a popular 1970s fashion trend before commercial acid wash denim was introduced in the 1980s.

In the 2000s, stonewashed jeans were heavily distressed, with premade holes, frayed edges and extensive fading caused by sandblasting. This substantially reduces the quality of the products and the life of the equipment and increases production costs.

On the other hand, Acid washing jeans avoided some of these problems but came with added dangers, expenses, and pollution. Environmental regulations have put profound pressure on the textiles industry to generate less pollution. But the actual process involves treating the wastewater and disposing of the sludge represents a growing portion of the production costs for a pair of jeans.

You may be thinking what to do now?

What’s the fate of our jeans now?

No need to worry!

There is a method called ‘biostoning’ which basically relies on the action of enzymes to selectively modify the fabric surface. Enzymes have been used in the textiles industry since the turn of the century to remove starchy and waxy residues from raw materials and to give the fabric a uniform finish. The important enzyme which is using in this process is ‘cellulase’.

Cellulase

Cellulases are hydrolytic enzymes that catalyze the breakdown of cellulose to smaller oligosaccharides and finally to glucose molecules. Cellulase activity involves a multicomponent enzyme system combining at least three types of cellulase working synergistically.

There are a number of cellulases available, each pertain their own special properties. These can be used either alone or in combination in order to attain a specific look. Heikinhemo et al. (2000) demonstrated that Trichoderma reesei endoglucanase II was very effective in removing color from denim, producing a good stonewashing effect with the lowest hydrolysis level.

Later Miettinen-Oinonen & Suominen (2002) developed new genetically engineered T. reesei bacterial strains which are able to produce elevated amounts of endoglucanase activity. Cellulase preparations derived by the new T. reesei over-production strains proved to be more efficient for stonewashing than those produced by the parental strain.


Cellulases are the most successful enzymes used in textile wet processing, especially finishing of cellulose-based textiles, with the goal of improved appearance. Traditional stonewashing of jeans involves amylase-mediated removal of starch coating (desizing process) and treatment (abrasion) of jeans with the pumice stone in large washing machines. Cellulases have been successfully used for the biostoning of jeans and biopolishing of cotton and other cellulosic fabrics.

During the biostoning process, cellulases act on the cotton fabric and break off the small fiber ends on the yarn surface, thereby loosening the dye, which is easily removed by mechanical abrasion in the wash cycle. The advantages in the replacement of pumice stones by a cellulose-based treatment include less damage to fibers, increased productivity of the machines, and less work-intensive and environment benign.

There are certain disadvantages of cellulase treatment. It could leave marks of backstaining like blue threads becoming more blue or white threads becoming blue. To get rid of such unwanted re-coloration of threads, the jeans are rigorously washed adding surfactants to it. This process could result in color-fading of jeans and there is added usage of water for the washing. Thus wastage of water and the certain amount of backstaining could be experienced.


Reference

1] © From, Application of enzymes for textile fibres processing, Rita Arau’jo, Margarida Casal, & Artur Cavaco-Paulo.

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