Stone+Washing+Jeans+and+Cellulase+(Jenny+Suh)

Jeans, Jeans, Everywhere!
The average American owns **twelve** pairs of jeans. **200 million pairs** of jeans are sold per year in Europe alone. Jeans now make up a global industry worth **$700 billion**. But not many people seem to know that **biology** plays a critical role in the jean industry. Regardless of color, style, or brand, it is likely that your jeans were subjected to “stone-washing” to give it a smoother, softer feel. In the early 1980s, this was done by rotating the denim in a drum together with stones, which acted like sandpaper and abraded the jeans. However, as it was difficult to control the amount of abrasion the fabric was subjected to, and acid-washing jeans caused environmental problems, a new method of “stoning” jeans was needed to keep our jeans smooth and comfortable. This is where biology came to the rescue: a technique known as “biostoning” with the **[|enzyme cellulase]** was introduced to Europe in 1989 and later adopted by the US.

Enzymes: A Brief Overview

 * [|Enzymes]** are proteins that speed up chemical reactions without being changed themselves. Enzymes bind to **[|substrates]** (reactants that enzymes work on) to either catabolize or anabolize it. As proteins, enzymes have certain common properties:


 * Enzymes have a precise 3D shape. This gives their **active sites** (area of an enzyme that substrates bind to) specificity and allows each enzyme to only bind to and catalyze one specific substrate.
 * Enzymes are inactivated by high temperatures. They work best at “optimum” temperatures at around 40 degrees Celcius and are damaged by temperatures above that and become denatured, the shape of their active sites no longer corresponding to its substrate.
 * Enzymes are also affected by pH, working best at a pH of about 7 and becoming denatured at very alkaline or acid conditions.

//cycle of an enzyme effect of temperature on enzyme activity//

The Enzyme Cellulase
Cellulase, with an “-ase” ending name common with most catalysts, is the main enzyme used in to “biostone” jeans. The enzyme is produced chiefly by fungi, bacteria, and protozoans. Cellulase speeds up the break-down of [|cellulose], which is present in jeans as the main component of cotton and other natural plant fibers.

Cellulase and Cellulose
As cellulose is a material present in all jeans, the addition of the enzyme cellulase results in an immediate break down of the fibres in the denim. More specifically, the surface cellulose bind to the active sites of cellulase enzymes, breaking molecular bonds and releasing indigo dye particles from the surface of the jeans. At the end of the reaction, only the dye has encapsulated, leaving the jeans intact and now “faded”.

//an indigo dye molecule//

Why is Cellulase Important, Anyway?
Cellulase is the major industrial enzyme used to soften and fade jeans. Meanwhile, the demand for stone-washed jeans has increased due to their wearability and attractive appearance. (//Gap// reports that more than 50% of their jeans now sold in stores are put through “biowashing”). Out of all the techniques employed in the jean industry, “biowashing” with cellulase enzymes is the most preferred due to its environment-friendliness (unlike using pumice stones or acid, enzymes can be recycled and do not pose a threat to employee health) and effectiveness (as cellulase, an enzyme is affected by different temperature and pH and this in turn can be used to control the different levels of stonewashing.)

Cellulase: Other Applications
Not only is cellulase used for its catalytic properties in the jean industry, but it is also employed in a variety of other industries. They include:
 * The breaking-down of cellulose in commercial processing of coffee beans
 * The hydrolysis of natural fibres in waste processing
 * Fermentation of biomass into biofuels (mostly experimental at the moment)

Did You Know..? Interesting Facts about Jeans

 * Levi Strauss, the founder of Levi Strauss & Co, the first major jeans company, was born Leob Strauss and later changed his name. Can you imagine slipping into a pair of [[image:zipper.jpg width="84" height="90" align="right"]]“Leob 501’s”?
 * Even though most of today’s jeans are made of denim, they are named after “jean cloth” a completely different material that was made up of entirely cotton in the eighteen century.
 * Most jeans’ zippers say “YKK” on them, after “Yoshida Kogyo Kabushikikaisha”, a Japanese zipper company founded in 1934 by Tadao Yoshida.



So next time you put on a pair of jeans, just remember: Even though the label //says// //stone// washed, stones aren't really used at all in the process of making them look faded. Instead, when you see the words "stone washed," think of those industrious little enzymes that helped make jeans nicer and more comfortable to wear.

__Works Cited:__ http://www.europabio.org/documents/JEANS.pdf http://www.schoolscience.co.uk/content/5/chemistry/catalysis/catsch8pg8.html http://www.novozymes.com/en/MainStructure/PressAndPublications/Biotimes/Articles/2004/2.+June/Fitting+enzymes+for+tight-fitting+jeans.htm http://134.68.135.1/jitt/sampler/biology/bio_archive/goodfor15.html http://www.answers.com/cellulase http://www.googobits.com/articles/p7-2448-good-jeans-how-to-find-em-and-the-story-behind-em.html